Fracture Mandible, 1E (2012)

FRACTURE MANDIBLE

FRACTURE MANDIBLE Rajesh R Yadav MS (ENT) DORL FCPS Assistant Professor Rajawadi Hospital Formerly Registrar Shri Harilal Bhagwati Hospital Mumbai, Maharashtra, India

Akancha R Yadav BDS Dental Consultant Mumbai, Maharashtra, India

Prakash V Dhond MS (ENT) DORL Honorary ENT Consultant Shri Harilal Bhagwati Hospital Mumbai, Maharashtra, India Foreword

Chris De Souza

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Dedicated to

Dinesh Yadav In memory of my brother Dinesh Yadav, who is still there with me and in me. His sweet memory always keeps him alive. I miss him in every step of my life. Rajesh R Yadav

Foreword I am pleased and honored to write the foreword of this book on the Fracture Mandible. My initial reaction was one of amazement when I saw how well the book was written. When I finished reading it, I did feel that it was so well written that it was definitely worth publishing and that all of us should possess a copy of it and learn from it. It is lucid, well organized and extremely well illustrated. It is also an unusual book dealing with a problem that so far was in the realm of facial plastic surgery. The book is full of authors’ passion in dealing with this problem and this passion is full of enthusiasm and deep insight. I have long felt that otolaryngologists need to expand their expertise and deal with facial plastic surgery in an in-depth way. As victims of high velocity trauma find their way to emergency rooms all over globe we will definitely find that this book become extremely relevant. I look forward to seeing this book go into several editions and I wish to see its scope and purpose expand. I have no doubt that these talented enthusiastic surgeons and authors with their passion and vision accomplish all of this. Chris de Souza MS DORL DNB FACS Honorary ENT and Skull Base Surgeon Tata Memorial Hospital, Mumbai, Maharashtra, India Consultant Otolaryngologist and Head Neck Surgeon Lilavati Hospital and Holy Family Hospital Mumbai, Maharashtra, India

Preface In the modern era of rapid life, vehicular accidents and violence are a common occurrence. Fractures of the mandible are gaining attention due to the upward trend of accidents of two wheelers and other motor vehicles. Before making an attempt of reducing the fracture, it is of utmost importance to learn not only the relevant anatomy but also the development, the dentition, the mechanisms of mandibular injuries and the different muscle forces acting on different fragments of mandible. Although management of mandibular fractures is routinely included in the realm of plastic and reconstructive surgery or maxillofacial surgery, it may not be possible to avail of such expertise all at times and in every region of even a city like Mumbai, let alone managing such cases in more peripheral hospitals. When faced with such situations, we ventured to learn the art of same and, after managing more than two hundred cases of fracture mandible, we thought of putting our experience on a paper so that others can benefit from our work. We do not claim that this is the best way, but we hope it can be of great help to our friends working at different levels especially those with smaller, private setups where, we will be happy to fill in the gaps in the required expertise. We present here, to you, an overview of different methods of fixation, anesthesia, anatomy and overall treatment. With our own experience, we felt that even ENT Surgeons can deal with fractures of the mandible confidently. The purpose of this book is to motivate more and more ENT Surgeons to do so. We have avoided some of the techniques that are not often used now to fix the mandible (e.g. external fixation techniques, nonrigid fixation techniques, etc.) in order to stay abreast with the current trends in management. We are grateful to our teachers, paramedical staff and patients who had shown confidence in us. We request the readers to point out any shortcomings in our present effort to share our experience as it is a learning process and learning never stops.

Rajesh R Yadav Akancha R Yadav Prakash V Dhond

Acknowledgments First and foremost, I would like to thank god for giving me the opportunity and skill to do this work. I am thankful to my parents for always showering their blessings on us. I am most grateful for the continued motivation and contribution bestowed upon me by my co-editor that includes my mentor Dr Prakash V Dhond and Dr Akancha R Yadav. The greater part of my experience comes from Shri Harilal Bhagwati Municipal General Hospital, Mumbai, Maharashtra, India, which for me is more than a temple. Here I had the good fortune of also having the expert guidance of Dr Lalit Seth. My sincerest thanks go out to my patients who have put their faith in my endeavors. I would like to thank the administrators, particularly Dr Mahendra Wadiwala, Dr Dinesh Shetty, Dr Bhatt, Anesthetist, Dr Bhavana Wadiwala and others, who trusted me and allowed me to manage such cases here. I am thankful to my brother Sunil Yadav who helped me in writing this book. I am grateful to Dr Ajay Haryani (Plastic Surgeon) from whom I learnt the procedure. I am grateful to Dr Deepak More and Dr Girish Surlikar, my buddies, my friends, and everything who I trust will be always there for me in need. Rajesh R Yadav

Contents 1. Dentition.................................................................................. 1 2. Fracture Healing and Biomechanics of Mandible ................ 6 3. Anatomy of Mandible........................................................... 12 4. Classification of Mandible Fractures .................................. 18 5. History and Clinical Examination........................................ 28 6. Radiology .............................................................................. 38 7. Preliminary Treatment .......................................................... 39 8. General Treatment of Fracture Mandible ............................ 42 9. Anesthesia for Fracture Mandible ....................................... 63 10. Specific Treatment of Fracture Mandible ........................... 74 11. Surgical Approaches ............................................................ 83 12. Fracture of Mandible in Children ....................................... 98 13. Postoperative Care ............................................................. 100 14. Complications ..................................................................... 104

Index ......................................................................................................... 111

Dentition / 1

1

Dentition

By 5 to 6 months of age the deciduous (temporary) teeth begins to erupt. The lower central incisors are first teeth to erupt, the child has a total of 20 teeth, 10 in upper and 10 in lower dental arch by the age of 20 to 24 months. Deciduous teeth consists of incisors, the cuspid teeth, the deciduous molars. The first permanent molar erupt behind the second deciduous molar by the age of 6 years, at the age of 6 years permanent incisors erupt, at the age of 9 years the permanent lateral incisors have erupted. At the age of 10 to 11 years the deciduous molar teeth are replaced by the permanent premolar teeth. At the age of 12 to 13 years the second permanent molar teeth and permanent canine teeth have erupted. All permanent teeth have erupted by the age of 14 years. When all the permanent teeth have erupted, the adult has 32 permanent teeth, 8 in each quadrant. Human primary or deciduous teeth eruption sequence Maxillary Central incisor 7½ months Lateral incisor 9 months Cuspid 18 months First molar 14 months Second molar 24 months Mandibular Central incisor Lateral incisor Cuspid First molar Second molar

6 months 7 months 16 months 12 months 20 months

Human permanent teeth eruption sequence Maxillary Central incisor 7–8 years Lateral incisor 8–9 years Cuspid 11–12 years

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First premolar Second premolar First molar Second molar

10–11 years 10–12 years 6–7 years 12–13 years

Mandibular Central incisor Lateral incisor Cuspid First premolar Second premolar First molar Second molar

6–7 years 7–9 years 9–0 years 10–12 years 11–12 years 6–7 years 11–13 years

Fig. 1.1: Diagram illustrates various dental and oral terminologies

The Angle’s classification of malocclusion describes the skeletal relationship between the teeth of maxilla and the mandible. The first step in identifying abnormal occlusal patterns is to count the teeth, identifying those that are missing and those that are present. Missing teeth in the partially dentulous patients can produce changes in dental relationships. The relationships between the central incisors of the mandible and the maxilla (the midline

Dentition / 3

relationship to the jaws) and the relationships of the cuspid and the first molar teeth on each side serve as a principle guides to the establishment of proper occlusion. By the study of models, the wear-facet pre-existing occlusion can often easily be recognized. Where the teeth have habitually come together are indicated by wear-facets. A patient who had a class III oclussion relationship (skeletal malocclusion) before injury would be impossible to treat by attempting to force a teeth into a neutral occlusal relationship. A class I (neutral) occlusion is one of which the mesial buccal cusp of the upper first molar occludes with the mesial buccal groove of the mandibular first molar. The protruding or jetting type of jaw is known as class III malocclusion (mesial occlusion), and the retrusive or undeveloped jaw is termed class II malocclusion (distocclusion). Other abnormalities of occlusal relationship in the lateral direction, referred to as crossbite. Openbite or absence of occlusal contact in any area should be noted. This may occur laterally, anteriorly or anterolaterally and may be unilateral or bilateral. In the injured patient in whom teeth or segment of bone are missing, it may be difficult to determine what the normal occlusal relationship should be.

Fig. 1.2: The occlusal relationships between the first molar and cuspid teeth are indicated

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Normally patient is helpful in advising the physician about the pre-exisiting occlusal pattern and can comment on whether the teeth are coming together properly. The perception of the patients is one of the most sensitive indicators of proper allignment after jaw fracture treatment.

Fig. 1.3: Dental terminology

In head injury patients, when cooperation is not possible study models become more important. Information may also be obtained from the patients family, from old photographs that demonstrates the dentition or from dentist or orthodontists who may have treated the patient previously or perhaps have taken radiographs or have models. In older patients wear-facets on the teeth give clues to pre-existing relationships. A patient in neutro-occlusion, for instance, often shows more wear surfaces on the outer (labial) edges of the lower anterior and on the under (lingual) surfaces of the maxillary anterior teeth. The wear-facets shows that the teeth previously occluded in a normal relationship. The patient with a severe retruded jaw usually has no wearfacets on the incisor edges of the lower anterior teeth. The patient who has a protuding lower jaw may have worn surfaces on the outer anterior edge of the maxillary teeth. Dental consultation may be helpful when the apparent occlusion does not fit a precise, pre-existing pattern. It is important TO RESTORE THE OCCLUSION IN FRACTURE OF THE JAWS TO THE PREEXISTING DENTAL RELATIONSHIPS. Alternatively (and less desirably) the occlusion should be brought into a range where it can easily be corrected with orthodontic manipulation. It is necessary that the

Dentition / 5

teeth brought into the best possible occlusal relationship so that adequate chewing surface and joint function occur after the reduction, fixation, and consolidation of jaw fractures. SUMMARY

 Try to restore occlusion in fracture mandible to pre-existing dental relationship.  Three types of occlusion Class I: Normal occlusion Class II: Disto-occlusion Class III: Mesio-occlusion  Try to have knowledge of occlusion of pre-existing dental relationship before operating fracture mandible.  Normal occlusion (pre-existing occlusion) is desired final result of the treatment of fracture mandible.

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2

Fracture Healing and Biomechanics of Mandible

Two types of bone found in the body—cortical and trabecular. Cortical bone is dense and compact. It forms the outer layer of the bone. Trabecular bone makes up the inner layer of the bone and has a spongy, honeycomb-like structure. Throughout life, bone is constantly renewed through a two-part process called remodeling. This process consists of resorption and formation. During resorption, special cells called osteoclasts break down and remove old bone tissue. During bone formation, new bone tissue is laid down to replace the old. Several hormones including calcitonin, parathyroid hormone, vitamin D, estrogen (in women), and testosterone (in men), among others, regulate osteoclast and osteoblast function. In the process of fracture healing, several phases of recovery facilitate the proliferation and protection of the areas surrounding fractures and dislocations. The length of the process depends on the extent of the injury. The process of the entire regeneration of the bone can depend on the angle or dislocation of fracture. While the bone formation usually spans the entire duration of the healing process. While immobilization and surgery may facilitate healing, a fracture ultimately heals through physiological processes. The healing process is mainly determined by the periosteum (the connective tissue membrane covering the bone). The periosteum is one source of precursor cells which develop into chondroblasts and osteoblasts that are essential to the healing of bone. The bone marrow (when present), endosteum, small blood vessels, and fibroblasts are  other  sources  of  precursor  cells.

Phases of Fracture Healing There are three major phases of fracture healing, two of which can be further sub-divided to make a total of five phases; 1. Reactive phase i. Fracture and inflammatory phase ii. Granulation tissue formation

Fracture Healing and Biomechanics of Mandible / 7

2.  Reparative phase iii. Cartilage callus formation iv. Lamellar bone deposition 3.  Remodeling phase v. Remodeling to original bone contour

Reactive After fracture,  the  first  change  seen  by  light  and  electron  microscopy  is  the presence of blood cells within the tissues which are adjacent to the injury site. Soon after fracture, the blood vessels constrict, stopping any further bleeding. Within  a  few  hours  after  fracture,  the  extravascular  blood  cells form a blood clot, known as a hematoma. All of the cells within the blood clot degenerate and die. Some of the cells outside of the blood clot, but adjacent to the injury site, also degenerate and die. Within this same area, the fibroblasts survive  and  replicate.  They  form  a  loose  aggregate  of  cells, interspersed with small blood vessels, known as granulation tissue.

Reparative Days after fracture, the cells of the periosteum replicate and transform. The periosteal cells proximal to the fracture gap develop into chondroblasts which form hyaline cartilage. The periosteal cells distal to the fracture gap develop into osteoblasts which form woven bone. The fibroblasts within the granulation tissue develop into chondroblasts which also form hyaline cartilage. These two new tissues grow in size until they unite with their counterparts from

Fig. 2.1: Healing of fracture (stage 1)

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other parts of the fracture. These processes culminate in a new mass of heterogenous tissue which is known as the fracture callus. Eventually, the fracture gap is bridged by the hyaline cartilage and woven bone, restoring some of its original strength. The next phase is the replacement of the hyaline cartilage and woven bone with lamellar bone. The replacement process is known as endochondral ossification with  respect  to  the  hyaline  cartilage  and bony substitution with respect to the woven bone. Substitution of the woven bone with lamellar bone precedes the substitution of the hyaline cartilage with lamellar bone. The lamellar bone begins forming soon after the collagen matrix of either tissue becomes mineralized. At this point, the mineralized matrix is penetrated by channels, each containing a microvessel and numerous osteoblasts. The osteoblasts form new lamellar bone upon the recently exposed surface of the mineralized matrix. This new lamellar bone is in the form of trabecular bone. Eventually, all of the woven bone and cartilage of the original fracture callus is replaced by trabecular bone, restoring most of the bone’s original strength.

Fig. 2.2: Healing of fracture (stage 2)

Fig. 2.3: Healing of fracture (stage 3)

Remodeling The remodeling process substitutes the trabecular bone with compact bone. The trabecular bone is first resorbed by osteoclasts, creating a shallow resorption pit known as a “Howship’s lacuna”. Then osteoblasts deposit compact bone within the resorption pit. Eventually, the fracture callus is remodelled into a new shape which closely duplicates the bone’s original

Fracture Healing and Biomechanics of Mandible / 9

shape and strength. The remodeling phase takes 3 to 5 years depending on factors such as age or general condition. Healing of fracture bone is divided into two types: a. Primary bone healing (Direct bone healing) • Gap healing • Contact healing b. Secondary bone healing (Indirect bone healing)—when semirigid fixation, nonrigid fixation is done or patient fracture site is not surgically treated.

Primary Bone Healing It occurs when rigidity and anatomic reduction exists. It also takes place in cancellous bone without rigid stabilization if no gross mobility is present. Osteogenic cells and capillaries proliferate in the medullary bone on both sides of fracture, forming new bone along the fracture site. Primary bone healing is of two types:

Gap Healing When small gaps occur between bone segments, within a few days after fracture, gap healing begins at these points. Blood vessels from periosteum, endosteum or haversian canals invade the gaps, bringing mesenchymal osteoblastic precursors. Bone is deposited directly on the surfaces of the fractured segments without resorption and without intermediate cartilage formation.  Gap < 0.3 mm—lamellar bone forms directly  Gap between 0.3 to 1 mm—woven bone forms first followed by lamellar bone. Formation of lamellar bone occurs over a period of six weeks. Lamellar bundles are oriented at right angles to the longitudinal axis of remaining bone.

Contact Healing It occurs through the formation of a bone metabolizing unit (BMU) a bone remodelling unit (BRU) or a bone repair unit (BRU) which are all synonyms for the newly forming (or regenerating) osteon. Advancing group of osteoclasts followed by vessels and cells differentiated into osteoblasts and form new bone. Osteoclasts begin to cut away cores on either sides of fracture, progressing towards the fracture side, through necrotizing bone and into opposing bone

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ends  proceding  at  a  rate  of  50  to  80  µm/day.  The  result  in  bone  provides  a pathway for vessels in growth and osteoblastic proliferation with formation of new bone. Osteon forms at a rate of 1 to 2 µm/day. Complete reconstruction of cortex takes place within six months. Gap healing begins almost immediately in areas where a space of up to 1 mm exist between fracture ends. Gaps are filled by appositional bone formation remodeling then restores the architecture. In areas of contact healing consolidation is achieved through a haversian remodeling alone. Osteoclasts produce pathways between fracture fragments, which are then bridged by newly formed regenerating osteons.

Factors Affecting Bone Healing Local      

Soft tissue trauma Adequate reduction Early fixation Infection Loss of tissue Restoration of function

General   

Age—younger patients healing is faster Nutrition Medically compromised patient—diabetes melitis, HIV

Biomechanics of Mandible This biomechanics of the mandible is a complex topic, there are various forces which are applied on the mandible, e.g. biting force or muscle force. The masticatory function of mandible is governed by influence of jaw opening muscle inserted on the lingual aspect of the anterior part and the jaw closing muscle on the posterior part of the mandible. The anatomical form of mandibular body and the influence of muscular pull create characteristic stress within the bone. This forces applied on a mandible causes varying zones of tension and compression force. Normally, on the superior portion of the mandible, tension zone is applied and its maximum at the angle of mandible. On the inferior border of mandible compression force is applied. A torsional force also exists between the canines which increase its strength in midline. Osteosynthesis

Fracture Healing and Biomechanics of Mandible / 11

Fig. 2.4: Biomechanics of mandible

plates are applied in such a way to combat this compression and tension force. Additional osteosynthesis plate is applied at midline to combat the torsional force. SUMMARY

 Three phases of bone healing 1.  Reactive phase i. Fracture and inflammatory phase ii. Granulation tissue formation 2.  Reparative phase iii. Cartilage Callus formation iv. Lamellar bone deposition 3.  Remodeling phase v. Remodeling to original bone contour.  Primary aim of treatment of fracture mandible is to heal fracture mandible by direct method (primary intension), i.e. gap healing or by contact healing.  Proper reduction and maintenance of blood supply fasten bone healing.  Compression force are at lower border of mandible.  Tension force are at upper border of mandible.  Torsional force are at between canines and is maximum at midline.

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3

Anatomy of Mandible

The mandible is a movable, predominantly U-shaped bone consisting of horizontal and vertical segments, the horizontal segment consists of the body on each side and the symphysis area centrally. The vertical segments consist of the angles and the rami, which articulate with the skull through the condyles and the temporomandibular joints. The mandible is attached to other facial bones by a complex system of muscles and ligaments. The mandible articulates with the maxilla through the occlusion of the teeth. Though the prominence, position and anatomic configuration of the mandible are such that it is one of the most frequently injured facial bones.

Fig. 3.1: Impact of trauma to various site

Trauma to maxillary area (B) absorbed direct trauma transmitting to skull thus decrease impact to skull (cushion effect). Trauma to mandible (C) are transmitted directly to the base of the skull through the temporomandibular articulation. This in turn means that relatively minor mandibular fractures may be associated with a surprising degree of head injury.

Anatomy of Mandible / 13

The mandible is a strong bone but has several areas of weakness that are prone to fracture. The body of the mandible is composed principally of dense cortical bone with a small substantial spongiosa through which blood vessels, lymphatic vessels and nerves pass.

Areas of Weakness Presence of Teeth Body of the mandible has two components that is alveolar component which carries the teeth and basal bones. The presence of teeth make the bony structure weak, resulting alveolar fracture can occur independent of the basal bone. Teeth which have long roots or that are embedded in the bone also weaken the structure, external root of canine is the longest amongst all mandibular teeth, presence of impacted or unerupted third molar also make the structure weak.

Neck of the Condyle A thin neck of the mandibular condyle is an area of anatomical weakness and get easily fractured in response to any direct or indirect trauma to the mandible. Therefore, the mandibular condyle acts as a shock absorber in preventing the intracranial injuries.

Symphysis of the Mandible It is an area of fusion of two halfs of the mandible. The complete bony union takes place at the end of the first year of life but this line of fusion remains relatively weak point in the structure.

Angle of the Mandible The trajectories of the mandible change their direction where the body and ramus meet. The angle of mandible is anatomically as well as physiologically weak structure. It is further weakened by the presence of an impacted tooth. The attachment of the muscles on the mandible anterior to the angle pull it downwards and backwards whereas the muscles attached posterior to the angle pull upwards and forwards. This is a significant observation in reference to the displacement of the fractured fragments.

Presence of Foramina Weaken the structure but this point is contested by many workers as presence of foramina add to the compactness of the bone. The fracture of the

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mandible in the-tooth bearing area normally compound into the oral cavity, and tooth in the line of fracture poses danger of being a source of infection.

Mandibular Muscles The various muscles attached to the mandible can be grouped as: 1. Muscles of facial expression 2. Muscles of mastication 3. Accessory muscles of mastication.

Muscles of Facial Expression The muscle of facial expression have their origin from the bone and insertion into the skin. These muscles play no role in the displacement of the fractured mandible because to displace the bone muscle should have attachment on fixed ends, i.e. a bone only.

Muscles of Mastication Masseter, medial pterygoid, temporalis and external pterygoid are strong muscles that help in closing and opening movements of the jaw. These muscles play a major role in the fracture displacement especially of the angle and condyle region. These muscles have strong tendonous attachment at the site of origin and insertion. The masseter and medial pterygoid muscles that form the sling of the mandible displace the ramal fragment upward. They are aided in their action

Fig. 3.2A: Muscle attachment from lateral side

Anatomy of Mandible / 15

Fig. 3.2B: Muscle attachment from medial side

Fig. 3.2C: Muscle attachment (horizontal view)

by temporalis muscle as well. This fragment is usually displaced medially because of the larger functional directional pull of the medical pterygoid muscle. The medial pterygoid is more medially placed in comparison to the masseter muscle that runs a rather vertical course. The lateral pterygoid muscle that is attached to the neck of the condyle and meniscus runs an anteromedial course up to the pterygoid plate and scaphoid fossa thereby displacing the fractured condyle medially.

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Accessory Muscles of Mastication Muscles like mylohyoid, geniohyoid and digastrics have their origin from the bone as well as insertion into another bone. These are also strong muscles that pull the body of the mandible downward and medially. Symphysis is pulled downward and backward by suprahyoid group of muscles. Displacement of symphysis is also important because it leads to fall of tongue and respiratory distress on account of the attachment of the tongue to the mandible through genioglossus muscle.

Vascular Supply of Mandible An effective blood supply is very much important factor in healing of a fractured mandible bone. A mandible receives an endosteal supply via the inferior dental artery and vein and these vessels are important in young patients. Occasionally, a fracture of the body of the mandible will cause a complete rupture of the inferior dental artery. Whereas this vessel usually goes into spasm with spontaneous arrest of hemorrhage, this is not always the case and prolific bleeding can occur which is difficult to control. In this rare emergencies, the mandible fracture needs to be reduced immediately by manipulation and the bone ends held in rough alignment by a wire ligature around adjacent teeth. The other and more important blood supply to the mandible derives from the periosteum. The periosteal supply becomes increasingly important with ageing as the inferior dental artery slowly diminishes in size and eventually disappears. This fact has considerable significance for the healing of fractures in the elderly. Open reduction of fractures in this age group involves elevation of periosteum from the bones and further deprivation of blood supply to the fracture side with resultant delayed or non-union.

Other Important Structure Nerves The inferior dental nerve is frequently damaged in fractures of the body and angle of the mandible producing anesthesia or paresthesia within the distribution of the mental nerve on the side of the injury. There are numerous reported cases where the facial nerve has been damaged by direct trauma over the mandibular ramus. Occassionaly, the mandibular division of the facial nerve is damaged in isolation in association with a fracture of the body or angle.

Anatomy of Mandible / 17

Blood Vessels Apart from hemorrhage from the inferior dental vessels which has been mentioned, injury to major blood vessels is unusual in association with mandibular fractures. A large sublingual hematoma may result from rupture of dorsal lingual veins medial to an angle fracture. The facial vessels are vulnerable to direct trauma where they cross the lower border of the mandible anterior to the angle.

Temporomandibular Joint Traumatic arthritis can occur without a fracture of the condyle, from indirect transmitted violence. A synovial effusion occurs with widing of the joint space on radiographs. Such a joint is extremely painful and mandibular movement very restricted. When an intracapsular fracture of the condylar head occur there may be direct involvement of the temporomandibular joint with hemorthrosis. If this occurs in a young child it can lead to fibrous or bony ankylosis of the temporomandibular articulation and destruction of the growth potential of the condyle. Not infrequently a fractured condylar head is driven backwards with sufficient force to tear, the adjacent external auditory meatus and cause bleeding from the external ear. Such bleeding must be carefully distinguished from the middle ear bleeding which signifies a fracture of the base of the skull. Very rarely, the glenoid fossa is fractured as the mandibular condyle is driven against this thin part of the temporal bone but usually a fracture of the condylar neck prevents the other more serious injury occurring. SUMMARY

 Trivial trauma can cause major injuries so all trauma should be taken seriously.  Area of weakness are: – Presence of third molar (impacted) – Neck of condyle – Symphysis of mandible – Presence of foramina – Angle of mandible.

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4

Classification of Mandibular Fractures

Etiology of Fractures Vehicular accidents and assaults are the primary causes of mandibular facial fractures throughout the world. The other chief causes for these fractures are Work related falls, sporting injuries and industrial trauma.  Vehicular accidents  Assaults  Work related causes  Falls  Sporting accidents  Miscellaneous causes Thus the causes for maxillofacial fractures can be classified into: a. Intrinsic causes b. Extrinsic causes

Intrinsic Causes (Pathological Fractures) Fractures that occur due to intrinsic weakness of the bone and not due to force of impact. Pathological fractures occur because of underlying bony or systemic disease that causes one, many, or all bones of the skeletal system to be abnormal and thus more susceptible to fracture. Pathological fractures may occur from any type of trauma.  Bending force  Torsional force  Compressive force or shearing force Often the only force necessary to cause fracture is the persons weight, especially in the mandible it may be chewing force, thus spontaneous fracture occurs without overt trauma. Pathological fracture may occur through any of the following types of bony pathology.  Neoplasia  Bony cysts

Classification of Mandibular Fractures / 19

Osteoporotic bone  Osteoradionecrosis  Caused by secondary nutritional hyperparathyroidism  Localized bone infection (osteomylelitis)  Osteoporotic bone due to disuse following prolong external fixation or removal of a rigid internal device. Unfortunately, fracture may occur even as a sequela of improper implant placement due to the tensile forces acting on the bone during mandibular function. 

Extrinsic Causes      

Direct violence (fracture at the side of impact) Indirect violence (fracture caused due to transmission of impact) Bending forces Torsional forces Compression forces Shearing forces

Factors affecting displacement of the fracture:  Muscular pull on the fractured segment  Force of the impact  Site and direction of the fracture line  Muscular tear—damage of muscle attachment might lead to the displacement of certain fracture (coronoid)  Presence of teeth in the posterior segment—presence of posterior teeth may prevent displacement due to contact with the occlusal surface of the maxillary teeth.

Frequency of the Fracture In general, incident of fractures of the mandibular body, condyle and angle are relatively similar, while fractures of the ramus and coronoid process are rare. The literature may suggest that following mean frequency percentages based on location. Condyle - 29% Angle - 26% Body - 25% Symphysis - 15% Ramus - 4% Coronoid process - 1%

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Fig. 4.1: Various site of fracture

The mandible is involved in 70% of patients with facial fractures. The number of mandible fractures per patient ranges from 1.5 to 1.8. Mandible fracture patterns of a suburban trauma centre found that violent crimes such as assault and gunshot wounds accounted for a majority of the fractures (50%), while motor vehicle accidents were less likely (29%). The fractures of mandible area are classified based on the following criteria: a. Anatomical locations b. Site of injury c. Condition of the bone fragments at the fracture site d. According to the direction of the fracture and favourability for treatment e. According to severity of fracture f. Presence or absence of teeth in the jaws g. Clinical and radiological findings 1. A. B. C. D. E. F. G. H.

Classification based on anatomical location of the fractures Fracture of the symphysis Fracture of the canine region Fracture of the body of the mandible Fracture of the angle of the mandible Fracture of the ramus Fracture of the condyle Fracture of the coronoid process Fracture of the dentoalveolar

Classification of Mandibular Fractures / 21

2. Classification based on site of injury a. Direct fracture If the fracture occurs at the site of impact, it is labelled as direct fracture.

Fig. 4.2: Classification according to site of injury

b. Indirect fracture An indirect fracture is the one that occurs away from the site of injury. A trauma on side of the mandible can cause a direct fracture at the canine region on the same side and an indirect fracture of the angle of the mandible or neck of the condyle on contralateral side. 3. Classification based on the condition of the bone fragments at the site of the fracture This classification denotes the condition of the bone fragments at the fracture site and hints at the severity of trauma and damage to the soft tissues.

a. Simple fracture When there is break in continuity of the bone without any break in mucosa or skin membrane thereby the fracture fragments are not exposed to the external environment such a fracture is said to be simple fracture.

Fig. 4.3: Simple fracture

22 / Fracture Mandible

b. Compound fracture When the fractured ends of the bone are associated with the break in continuity of skin or mucous membrane thereby communicating with the external environment through the wound then it is called as compound fracture. As a rule, Fig. 4.4: Compound fracture fractures involving the tooth bearing area are always compound fractures because they communicate with the oral environment through gingival sulcus and periodontal ligament.

c. Comminuted fracture When the bone is splintered into more than two fragments, it is called as comminuted fracture. These are high impact injuries on account of major trauma.

Fig. 4.5: Comminuted fracture

d. Greenstick fracture The bone in children is soft elastic and there occurs an incomplete type of fractures at times. These appear as a crack in the bone in which only one cortex of the bone is fractured whereas other cortex is bent only as in the case of a green stick of a tree.

Fig. 4.6: Greenstick fracture

4. Classification according to the direction of fracture line and favorability for treatment This classification is basically restricted to the fractures of the angle of the mandible. The line of fracture is considered to determine the type of fixation required. A fractured line is considered favorable if the muscular pull resists the displacement of the fracture and in case the muscular pull distracts the fractured fragment away from the line of fracture favouring displacement, it is

Classification of Mandibular Fractures / 23

labelled as unfavorable fracture. Fractures of the angle of the mandible are influenced by the pull of the medial pterygoid, masseter and temporalis muscles that tend to displace the ramus in an upward and medial direction. However, the displacement of the fractured fragment is also influenced by the direction of the force, magnitude of the impact, site of fracture, presence or absence of teeth on each side of the fractured line. These fractures can be classified as follows: a. Horizontally favorable fractures When viewed from the side of the fracture line runs from the lower border of the mandible extending upward and backward to meet the upper border. The upward displacement of the posterior fragment is prevented by the anterior fragment. Fig. 4.7: Horizontally favorable fractures

b. Horizontally unfavorable fractures When the fracture line runs from the lower border of the mandible in an upward and forward direction to meet the alveolar crest, the upward movement of the posterior fragment is called as horizontally unfavorable fractures.

Fig. 4.8: Horizontally unfavorable fractures

c. Vertically favorable fractures When a fracture is viewed from above or occlusal surface, the fracture line that runs from buccal plate obliquely backwards toward the lingual plate, it will resist the medial displacement of the posterior segment. Such a fracture is called as vertically favorable fracture. Fig. 4.9: Vertically favorable fractures

24 / Fracture Mandible

d. Vertically unfavorable fracture When a fracture line viewed from above, extends from the buccal cortical plate coming forward to join the lingual cortical plate, it is labelled as vertically unfavorable fracture because the posterior segment can easily get displaced medially without any hindrance. Fig. 4.10: Vertically unfavorable fractures

5. Classification according to presence or absence of teeth Teeth may have important role to play in the management of the fracture since occlusion is considered to be a guide in reduction. When a teeth are not present, alternative method of treatment to simple wiring procedures are compelled to be considered. a. Class I – When teeth are present on both sides of the fracture line. b. Class II – When teeth are present only on one side of the fracture line. c. Class III – When both the fragments on each side of the fracture line are edentulous.

Fig. 4.11: Classification according to presence or absence of teeth

6. AO classification of mandibular fractures This classification is based on clinical and radiological findings and describes mandibular fractures along with soft tissue involvement. It has five components depending on the types of fractures and other associated findings: F Number of fractures L Localization (site) O Occlusion S Soft tissue involvement A Associated fractures

Classification of Mandibular Fractures / 25

These components are described further as under: Categories of fractures (F) F0 Incomplete fractures F1 Single fractures F2 Multiple fractures F3 Comminuted fractures F4 Fracture with bone defect Categories of localization (L) L1 Precanine L2 Canine L3 Postcanine L4 Angular L5 Supra-angular L6 Processus anticularis L7 Processus muscularis L8 Alveolar process Categories of occlusion (O) O0 No malocclusion O1 Malocclusion O2 Edentulous mandible Categories of soft tissue involvement (S) S0 Closed S1 Open intraorally S2 Open extraorally S3 Open intra-extraorally S4 Soft tissue defect Categories of associated fractures (A) A0 None A2 Fracture and/ or loss of tooth A3 Nasal bone A4 Zygoma A5 Le Fort I A6 Le Fort II A7 Le Fort III Grades of severity (I-V) Grade I and Grade II: These are closed fractures.

26 / Fracture Mandible

Grade III and Grade IV: These are open fractures Grade V: This includes open fracture with a bone defect and fractures due to gunshot.

Fracture Displacement The pull of the muscles are described above and the direction of the line of the fracture along with the intensity of the force hitting, the jaw are responsible for the displacement of the mandibular fragments are described as under.

Fracture Condyle There is no dislocation of the condyle if only a crack in a neck appears without any tear in the capsule of the joint and periosteum of the bone but if there is a fracture causing tear, anterior or medial dislocation of the condyle due to the attachment of lateral pterygoid muscle will take place.

Fracture Angle of the Mandible As explained earlier the unfavorable lines of the fracture from the treatment point of view in the angle region favor superior and medial displacement of the posterior segment. If the lines are favorable both horizontally and vertically, there are minimal chances of displacement.

Fracture of Body of the Mandible Both the elevators and depressor muscles play a role in displacement. The mylohyoid muscles displaces the fragments medially and inferiorly. If the fracture line is favorable, no displacement is seen unless there is some extreme degree of violence. In unfavorable line of fracture both in horizontal and vertical direction, i.e. if the fracture line is running from the lingual to buccal table in an anterior direction and from lower to upper border again in an anterior direction, the larger fragment of bone bearing the dental arch will be displaced inferiorly and medially.

Fracture in the Canine Region Bone is weakened in this region due to the long root of the canine hence, fracture is more common in this region. The role of causing displacement is played by depressor group of muscles of the jaw. Bilateral fractures cause a lot of displacement depending upon the line of the fracture.

Classification of Mandibular Fractures / 27

If the fracture lines are running towards each other, i.e. converging lines from labial to lingual table of the mandible as well as from superior to inferior border, no displacement is expected. However, if the lines are unfavorable ie. If the fracture lines are running divergently from labial to lingual table of the mandible as well as superior to inferior border, the central fractured fragment is pulled downward and backward by the mylohyoid, geniohyoid, digastrics and genioglossus muscles. It is further complicated by the collapse of the fragment on the lateral side, medially towards each other making a closed reduction very difficult.

Fracture of Symphysis A vertical midline fracture normally exhibits no displacement but if the fracture line runs an oblique course, the balance of the muscles is disturbed causing displacement of the fragments backwards and downwards.

Fracture of Ramus of the Mandible The sling of the mandible formed by the masseter and medial pterygoid muscle forms a thick protective case around the ramus and gives it a splinting action. Generally talking, there is no dislocation of the fractured fragments of the ramus but in injuries like gunshot wounds, there may be shattering of bone.

Fracture of Coronoid Process Fractures of the coronoid process of the mandible are not commonly seen. In cases there is a fracture with a tear in the periosteum, the tendonous attachment of the temporalis muscle will pull the fractured coronoid process upwards. SUMMARY

 Vehicular accidents and assault are main cause of fractures.  Condyle and angle are the most common site of the angle  Any break in mucosa or a skin with fracture mandible is compound fracture.  Favorable fractures are those fractures in which because of muscle pull fractured fragments are brought together.  Unfavorable fractures are those fractures in which because of muscle pull fractured fragments are pulled away from each other.

28 / Fracture Mandible

5

History and Clinical Examination

History History is very much informative in case of fracture mandible.  A detailed history of patient should be taken  Any pre-existing disease should be enquired like: a. Systemic disease like diabetes and hypertension b. Psyschiatric illness c. Alcoholic withdrawal symptom d. Epilepsy e. Other endocrine, collagen diseases In such patient like psyschiatric, alcoholic withdrawn, epilespsy, intermaxillary fixation should be avoided.  History regarding etiology of fracture should be elicited. In cases of high velocity (RTA) suspect other fracture also in a body  Elicit regarding shape and size of the object causing injury, blow from a broad, blunt object can cause several fractures while smaller well defined object may cause single comminuted fractures. Since, impact of force is concentrated in small area  Try to elicit the direction of impact. Anterior blow on a chin can cause parasymphysis or bilateral condyle fracture. The examination of a patient with the fracture of the mandible takes place in three stages: 1. Instant and rapid assessment 2. General clinical examination of the patient 3. Local examination of the mandibular fracture

Instant and Rapid Assessment Vehicular accident or assault patient who has a fracture mandible may sustain injury on another part of the body which may constitute actual threat to a life. This should be given a first priority than the facial trauma. It is always necessary to make a rapid assessment and start the resuscitation of patient first and then a detailed examination to be done.

History and Clinical Examination / 29

General Examination Fractures of the mandible are, of course, caused by trauma of varying degrees of severity and is reasonable to consider the possibility that this degree of trauma may also have caused injury elsewhere in the body. This is especially true if the patient has been involved in a accident such as road traffic accident or a fall from a considerable height. However, a simple blow on the lower jaw as a result of a fight or during the course of some game may result in force being transmitted to the cranium which results in serious injury or even death of the patient. It is unusual for a patient with a mandibular fracture to be shocked and if this condition is present some more serious injury should be suspected.

Local Examination of the Mandibular Fracture Preparation for Examination Before any detailed examination of the mandible, the face must be gently cleaned with swabs to remove blood clot, road dirt, etc. inorder that an accurate evaluation of any soft tissue injury can be made. The mouth similarly should be examined for loose or broken teeth or dentures, and any congealed blood removed with swabs held in nontoothed forces. During this gentle cleaning of face, the cranium and cervical spine are carefully inspected and then palpated for signs of injury. Finally, the mandibular fracture is examined in detail.

Extraoral Examination Inspection a. Swelling Many of the physical signs of a fractured bone result from the extravasation of blood from the damaged bone ends. This results in very rapid early swelling from the accumulation of blood within the tissues and later increase in the swelling resulting from increased capillary permibiality and oedema. Swelling and ecchymosis indicate the site of any mandibular fracture. b. Deformity There may be obvious deformity in the bony contour of the mandible. c. Gait of patient If considerable displacement has occurred the patient is unable to close the anterior teeth together and the mouth hangs open. A conscious patient may seek to support the lower jaw with his hand.

30 / Fracture Mandible

Palpation Palpation should begin bilaterally in the condylar region and then continue downwards and along the lower border of the mandible. If there is more displacement it may be possible to palpate deformity or elicty bony crepitus. Fractures of the body of the mandible are associated with injury to the inferior dental nerve in which case there will be reduced or absent sensation on one or both side of the lower lip.

Intraoral Examination 

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It is impossible to assist intraoral damage if the parts are obscured by blood. The buccal and lingual sulci are examined for ecchymosis. Submucosal extravasation of blood is often indicative of underlying fracture, particularly on the lingual side (Coleman’s sign). Ecchymosis in the buccal sulcus is not necessarily the result of the fracture as there is considerable soft tissue overlying the bone in this area and extensive brusing may follow a blow over the lower jaw insufficient to cause a fracture. However, on the lingual side the mucosa of the floor of the mouth overlies periosteum of the mandible which, if breached following a fracture, will invariably be the cause of any leakage of blood into the lingual submucuosa. The occlusal plane of the teeth is next examined, or if the patient is edentulous, the alveolar ridge. It is important to examine all the individual teeth and to note any luxation or subluxation along with missing crowns, bridges and/or fillings. Individually fractured teeth must be assessed for involvement of the dentine or pulp. Possible fracture sites are gently tested for mobility by placing a finger and thumb on each side and using pressure to elicit unnatural mobility. If the patient can cooperate, he is asked to carry out a full range of mandibular movements and any pain or limitation of movement recorded. Occasionally, this detailed examination fails to confirm. A mandibular fracture which is thought to be present from the history and presence of hematoma. In such cases, the flat of both hands should be placed over the two angle of the mandible and gentle pressure exerted. This maneuver will always elicit pain when even a crack fracture is present.

History and Clinical Examination / 31

Sign and Symptoms of Mandibular Fractures Fracture of the mandible can be divided according to their anatomical location into eight main types, these are: 1. Dentoalveolar 2. Condylar 3. Coronoid 4. Ramus 5. Angle 6. Body (molar and premolar areas) 7. Symphysis and parasymphysis 8. Multiple and comminuted fractures.

Dentoalveolar Fractures Dentoalveolar injuries are defined as those in which avulsion, subluxation or the fracture of the teeth occurs in association with the fractures of the alveolus.  They may occur alone or in combination with some other type of mandibular fractures.  Fracture of the crown of individual teeth may occur as a direct result of trauma or by forcible impaction against the opposing dentition.  Meticulous dental examination is essential and any missing fragments of crown or missing fillings noted. These may be invaded within the soft tissues or more rarely swallowed or inhaled.  Fractures of the roots of the teeth may be present which are difficult to diagnose clinically. Exclusively mobile teeth which do not appear to be subluxed are suspect and should be earmarked for later periapical radiographs.  Individual teeth may be missing and/or recent extraction wound suggest that the tooth concerned has been knocked out.  Occasionally, molar and premolar teeth appear superficially normal but close inspection reveals either a vertical split or a horizontal fracture just below the gingival margin resulting from indirect trauma against the opposing dentition or violent impact by a small hard object such as missile.  Fracture of the alveolus may be present with or without associated injury to the teeth.

32 / Fracture Mandible

Condylar Fractures These are the most common overall fractures of the mandible and are once most commonly missed on clinical examination. Condylar fracture may be unilateral or bilateral, and they may either involve the joint compartment as intracapsular fractures or the condylar neck when they are regarded as extracapsular. The extarcapsular fracture may exist with or without dislocation of the condylar head, and the upper fragment may either remain angulated on the lower portion of the ramus or be displaced medially or laterally.

Unilateral Condylar Fractures 

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There is often swelling over the temporomandibular joint area and there may be hemorrhage from the ear on that side. Bleeding from the ear results from laceration of the anterior wall of the external auditory meatus, caused by a violent movement of the condylar head against the skin in this region. It is important to distinguish bleeding originating in the external auditory canal from the more serious hemorrhage. The haematoma surrounding a fractured condyle may track downwards and backwards below the external auditor canal. This give rise to ecchymosis of the skin just below the mastoid process on the same side. This particular physical sign also occur with fractures of the base of the skull when it is known as “ battle’s sign.” In the recently injured patient there is invariably tenderness over the condylar area. When post-traumatic edema is present it is difficult to palpate the condylar head. The mandible deviates on opening towards the side of the fracture, and there is usually painful limitations of protusion and lateral excursion to the opposite side.

Bilateral Condylar Fractures 

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As with the unilateral fracture overall mandibular movement is usually more restricted extraorally then is the case with a unilateral fracture. As with the unilateral fracture derangement of the occlusion will be found only if the condyle is displaced on one or the other side causing shortening of the ramus. If both fractures have resulted in displacement of the condyles from the glenoid fossa or overriding of the fractured bone ends, an anterior openbite is found to be present.

History and Clinical Examination / 33 

In all cases of bilateral fracture there is a pain and limitation of opening and restricted protusion and lateral excursions.

Fracture of the Coronoid Process  

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This is a rare fracture. The fracture can be caused by direct trauma to the ramus but is rarely in isolation in the circumstances. If the tip of the coronoid process is detached, the fragment is pulled upward towards the infratemporal fossa by the temporalis muscle. This is difficult fracture to diagnose clinically. There may be tenderness over the anterior part of the ramus and hematoma. Painful limitation of movement, especially protrusion of the mandible may be found.

Fracture of the Ramus The fractures of the ramus are not common and there are two main types.

Single Fracture This is in effect a low condylar fracture with both the coronoid and condylar process on the upper fragment.

Comminuted Fracture Such a fracture always result from direct violence to the side of the face.  Swelling and ecchymosis is usually noted both extra and intraorally.  There is tenderness over the ramus and movements produced pain over the same area.  Severe trismus is usually present.  Inability to close and open mouth.

Fracture of the Angle  

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There is usually swelling at the angle externally . There may be obvious deformity. Within a mouth a step deformity behind the last molar tooth may be visible which is more apparent if no teeth are present in the molar region. Anterior open bite in bilateral angle fracture. Ipsilateral open bite in unilateral angle fracture. Retrognathic or flattened appearance of lateral aspect. Inability to close jaw causing premature dental contact.

34 / Fracture Mandible

Fracture of the Body (Molar and Premolar Regions) The physical signs and symptoms are similar to those of fractures of the angle as far as swelling and bone tenderness are concerned.  Inability to open or close mouth.  Ecchymosis, swelling, bone tenderness are similar to fracture of angle.  Dentate mandible even slight displacement of the fracture causes derangement of the occlusion.  Premature contact occurs on the distal fragment because of displacing action of the muscles attached to the ramus.  When there is a gross displacement, the inferior dental artery may be torn and this can give rise to severe intraoral hemorrhage.  Crepitation on palpation.  Flattened appearance of lateral aspect of face.

Fracture of the Symphysis and Parasymphysis 

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These fractures are commonly associated with fractures of one or both condyles. Ecchymosis on floor of mouth. The thickness of the anterior mandible between the canine regions often ensures that these fractures are fine cracks which are little displaced and may be missed if the occlusion is undisturbed locally. The presence of bone tenderness and a small lingual hematoma may be only physical signs. The fracture line is often oblique which allows overriding of the fragments with lingual inversion of the occlusion on each side. As such fractures are always the result of direct violence there is frequently associated soft tissue injury of the chin and lower lip. Posterior crossbite in symphysis fracture. Posterior open bite or unilateral open bite in parasymphysis fracture. Chances of paresthesia of lower lip as injury of mental nerve after emergence from foramina. Chances of airway compression in case of bilateral parasymphysis fracture with loss of tongue and loss of consciousness.

Multiple and Comminuted Fractures The physical signs of the multiple and comminuted fractures depend on the site and number of fractures. Multiple and comminuted fractures result from extreme direct violence and are usually associated with more severe soft tissue injury. In general comminuted fractures of the ramus, angle and molar regions are not

History and Clinical Examination / 35

associated with gross displacement of the fragments. However, comminution of the symphysis allows the lateral segments to collapse and presents a much more serious problem of management. SUMMARY

 See the patient as whole a. Resuscitate the patient first. b. Mandible treatment can wait.  Detailed examination can give rough idea of site of fracture.  Swelling and ecchymosis suggest underlying fracture mandible.  Deviation from normal occlusion, open bite, crossbite suggest fracture mandible.  Deformity, inability to close and open mouth suggestive of fracture mandible.  Look for inferior alveolar nerve or mental nerve paresthesia.

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6 A of a. b. c. d. e.

Radiology

precise radiological diagnosis is very much important for treatment plan fracture mandible. It depicts: A exact relationship of teeth in fracture line A type of fracture, simple or communited Number of fractures Area of fractures Degree of displacements.

Radiographs of mandible is divided into: a. Essential view It is available in all departments of radiology and can be done easily on all patients. b. Desirable view The equipments for the same view are not available in routine radiology department. The equipments are of specialized nature and cannot be done on severely injured patients.

Essential Radiographs a. Left and right oblique lateral view of mandible This view are used to demonstrate fracture of mandible ramus, body of mandible and symphysis region. b. Posteroanterior This view demonstrates fracture of body and angle with the type of displacements. An undisplaced fracture of condyle head is difficult to see in this view as it is obscured by superimposition of mastoid process. c. Reverse Towne’s projection This projection is used to demonstrate fracture of condyle region. As this avoid superimposition of mastoid bone. d. Intraoral 1. Periapical films are required to demonstrate a relationship of teeth to the line of fractures and any damage to the teeth itself.

Radiology / 37

2. Occlusal films can help us to evaluate the relationship of tooth root to the fracture.

Desirable Radiographs Panoramic Films Panoramic films are useful in defining location and displacement of mandible fracture. It has a accuracy rate of 92% for diagnosis of fracture. This films give a best single overall view of mandible and are specially valuable for demonstrating fracture in condyle region. The combination of posterioranterior view and a pantomogram obviates the need for further radiographs. The sites in which mandible fractures are most commonly under diagnose on this view are condylar angle and symphysis area especially if there is some blurring by the patients movement or hardware.

Advantages   

Simplicity of technique Good details Can visualize mandible and maxilla with root of teeth in one radiograph.

Disadvantages   

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Impractical for severely traumatic patients Cannot be done in all hospital set ups TMJ area, symphysis, dental and alveolar process region areas of which fine details cannot be appreciated Difficult to appreciate buccal and lingual bone displacement.

Computed Tomographic Scan Indications 1. 2. 3. 4. 5.

In cases of multiple facial injuries Cases of communated fractures Cases of missile injuries Cases of infected, malunion, nonunion fracture mandible In cases of vertical split fractures

The accuracy rate of ct scan is around 92%. This offers a very little advantage as a diagnostic tool in lower third of a face and are not justified for isolated mandibular fractures on either clinical or economic ground. It demonstrates detail of TM joint injury.

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Three-dimensional CT Scan It can be obtained to compare symmetry and volume of two side of bone of face. SUMMARY

 Posteroanterior view and a pantogram is all what needed in a simple case of fracture mandible.  Reverse townes view can be used for condyle fractures.  CT Scan indicated in complicated comminuted infected fracture mandible and associated with facial injuries.

Preliminary Treatment / 39

7

Preliminary Treatment

Most of the fractures of the mandible encountered are associated with fracture in other part of body or other injuries in body. It is not common for such patients to suffer from shock and evidence of acute circulatory collapse in itself is indicative of damage to other important structures. Trauma to the mandible does, however, frequently cause concussions from transmitted violence to the base of the skull.

Airway Maintenance Relatively minor injuries which cause intraoral bleeding and fracture of teeth or dentures can lead to airway obstruction in an unconscious or semi-conscious patient. The essential first aid required consists of careful examination of the mouth and the removal of all fragments of teeth, broken fillings and dentures. If suction is available blood clots and the saliva should be evacuated and the patient positioned so that further bleeding and secretions can escape from the oral cavity. If the symphysis region is fractured and particularly if it is comminuted there is some danger of the tongue falling back and obstructing the airway in a patient who has lost voluntary control of the intrinsic musculature. Occasionally a suture passed through the dorsum of the tongue may assist in controlling its position. The most satisfactory posture for an unconscious patient is lying on his side in the position used routinely during recovery from a general anesthetic. This position should be opted for transportation of a patient to an accident unit or another treatment center.

Blood Loss Serious blood loss is not common in mandibular fractures. Considerable blood loss can however occur, when there are extensive associated soft tissue lacerations, obvious bleeding points such as the facial vessel should be secured with artery forceps and a temporary dressing applied. Occasionally brisk and persistent hemorrhage originates from a grossly displaced fracture of

40 / Fracture Mandible

the body of the mandible. This can only be controlled by manual reduction of the fracture and temporary partial immobilization by means of a suture or wire ligature passed around teeth on each side of the fracture line.

Soft Tissue Lacerations It is desirable to close a soft-tissue wound within 24 hours of injury, as it is often possible to gain access and to stabilize bone fragments through overlying wounds, it is therefore advantageous, where possible, to combine soft tissue repair with definitive treatment of the fracture. If this is not possible because of the patient’s general condition the soft tissue must be dealt with separately under local analgesia as soon as possible after injury. Before closing wounds they must be cleaned to remove foreign material and so avoid subsequent unsightly tattooing of the scar. Wounds should be gently scrubbed if necessary with a mild antiseptic cleanser such as 1% cetavlon.

Support of the Bone Fragments In most of the cases temporary splinting of the fragments is unnecessary and such devices as the barrel bandage, webbing head cap with chin support, and Elastoplast chin strap are not only superfluous but may in some instances may cause the patient additional discomfort. If this type of first aid is applied it is salutary to observe how often the patient experiences relief when it is removed. Usually if any urgent immobilization of the fragment is required it is best to carry out a definitive standard fixation technique such as an arch bar and not to waste time with an ineffective temporary fixation.

Pain Control The majority of the patients with mandibular fractures do not appear to suffer much a pain, perhaps owing to the frequently associated neuropraxia of the inferior dental nerve. Some mobile fractures of the body of the mandible are, however, extremely uncomfortable and a potent cause of restlessness in a cerebrally irritated patient. This situation is one of the rare indications for giving priority to the immobilization of the mandible in the presence of other serious injury. It should be remembered that use of the powerful analgesics such as morphine is contraindicated as they depress the cough reflex and respiratory

Preliminary Treatment / 41

center and also mask pain which can be diagnostically important (e.g. from a ruptured spleen).

Control of Infection All fractures of body of mandible involving teeth are compound fractures as they are potential source of infection. Immediately injection augmentin should be given every 12 hourly for first 2 to 3 days. There are also chances of anaerobic infection. So injection metronidazole or oral metronidazole should be administered. SUMMARY

 Treat the life-threatening condition first.  Treatment of fracture mandible can wait.

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8

General Treatment of Fracture Mandible

Principal of fracture treatment of the mandible do not differ from fracture elsewhere in the body.

Principles a. Fracture reduction and fixation to restore anatomical relationships; b. Fracture fixation providing absolute or relative stability as the “personality” of the fracture, the patient, and the injury requires; c. Preservation of the blood supply to soft tissues and bone by gentle reduction techniques and careful handling; d. Early and safe mobilization and rehabilitation of the injured part and the patient.

Reduction Reduction of fracture means restoration of functional alignment of the bone fragment. In the dentate mandible reduction must be anatomically precise when teeth are involved and previously in a good occlusion. Less precise reduction may be accepted if part of the body of mandible is edentulous or there are no opposing teeth. The presence of teeth provides an accurate guide in most cases by which the fracture segment can be aligned. The teeth are used to access the reduction, check alignment of the fragment and assist immobilization. However the occlusion is used as a index for accurate reduction it is important to recognise any preexisting occlusion abnormality like anterior or lateral open bite were facets on individual teeth can provide valuable clues to previous contact areas. The teeth may on occasion be brought into contact during reduction and yet be occluding incorrectly owing to lingual inclination of fractured segment. Close reduction can be achieved in a case of mild displaced fracture. While widely displaced, multiple or extensive comminuted fractures will require a open reduction.

General Treatment of Fracture Mandible / 43

Immobilization Following accurate reduction of fragment, the fracture side need to be immobilized to allow the bone healing to occur. The period of the immobilization depends upon the sites of fractures, the presence of teeth, age of a patient and absence and presence of a patient.

Period of Mobilization A simple guide for a period of immobilization for fracture of mandible of a tooth bearing area are as follows Normally a 3 weeks of immobilization is required in a case of young adult with fracture of angle receiving early treatment in which teeth are removed from the fracture line. If a. Tooth retained in fracture line—add 1 week b. Fracture at the symphysis—add 1 week c. Age 40 years and over—add 1 or 2 week d. Children’s and adolescents—subtract 1 week

Fig. 8.1: Type of fixation

Thus if there is a fracture in a symphysis in a 40-year-old patient with tooth in a fracture line is retained then a 6 week immobilization is required (basic 3 weeks + 1 week for unfavourable site + 1 week for the age + 1 week for the teeth retained in a line of fracture). This rule is for guidance only. However, the fracture segments need to be tested clinically before this immobilization is removed or released.

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Intermaxillary Fixation Arch Bars Arch bars are preferred:  For temporary fragment stabilization in emergency cases before definitive treatment  As a tension band in combination with rigid internal fixation  For long-term fixation in conservative treatment  For fixation of avulsed teeth and alveolar crest fractures

General Considerations There are important points to consider before starting. The occlusion must be checked. In the case of jaw malformations, such as a deep bite deformity, it may be impossible to use arch bars. One pitfall when using arch bars is the risk of contamination of bloodborne infection from patients. Passing the wires to secure the arch bar can result in a puncture or tear in the surgeon’s glove and the possibility of disease transmission to the surgeon.

Fig. 8.2: Another way of arch bar application

General Treatment of Fracture Mandible / 45

A

B

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D E

Fig. 8.3: Fitting an arch bar. A— Selection of appropriate length and contouring of Erich arch bar. B— Arch bar to be placed on a teeth for a proper measurement. Extra length of the arch bar need to be trimmed and the posterior edge of the bar need to be bend to prevent soft tissue injury. C and D— Wire is passed above and below the arch bar and tightened so as not to obstruct the lug. It is important to make sure that this wires have been tightly applied by checking whether any vertical movement of arch bar is possible. The wire used are of normally of 26 gauge. E— Intermaxillary fixation can be established by either wires or by elastic

46 / Fracture Mandible

Wiring Techniques Gilmer Method This is the simplest way to establish intermaxillary fixation by gilmer method. This technique is simple and effective but has a disadvantage that mouth cannot be opened for inspection of the fracture side without removal of wire fixation. The method consists of passing wire ligatures around neck of available teeth and twisting them in a clockwise direction until the wire is tightened around its tooth. After adequate Fig. 8.4: Gilmers method of fixation number of wire has been placed in upper and lower teeth are brought into the occlusion and the wire are twisted one upper to one lower wire. A stainless steel 24 gauge or 26 gauge wire are usually applied.

Eyelet Method This method of fixation has the advantage that jaws may be open for inspection by removal of only the intermaxillary ligatures. This method consists of twisting a 20 cm length of 24 gauge or 26 gauge wire around a instrument to establish a loop. Both end of the wire are passed through the interproximal space from the Fig. 8.5: Eyelet method of fixation outer surface. One end of the wire is passed around the anterior tooth the other around the posterior tooth. One end of the wire may pass through the loop. The eyelet should project in upper jaw above and in lower jaw below the horizontal twist to prevent ends from impinging on each other. After establishment of sufficient number of eyelets the teeth are brought into occlusion and ligature are passed in loop fashion between one upper and one lower eyelet. The interjaw wires are twisted tightly to provide intermaxillary fixation.

General Treatment of Fracture Mandible / 47

Intermaxillary Fixation Screw Technique Intermaxillary fixation screws has been introduced as labour saving device. Intermaxillary fixation screws provide a rapid method of immobilization of teeth in a good dentician in uncomplicated fracture types. The number and position of this screws to be inserted is based on fracture types, the location of fracture and the surgeon preference. Screw must be position superior to the maxillary tooth roots and inferior to the mandible tooth root.

Fig. 8.6: Intermaxillary fixation screw technique

Disadvantages are minimal and a focused point of force application to maintain good intermaxillary fixation. The focus point of force applied may result in malocclusion by leaving the posterior dentician in an open bite.

Acrylic Splints These are useful in maintenance of intermaxillary fixation and in establishing the continuity of maxillary and mandibular dental arches in particular segment of missing teeth can be compensated with suitable design splint. These are useful in maintenance of intermaxillary fixation and in establishing the continuity of maxillary and mandibular dental arches in particular segment of missing teeth can be compensated with suitable design splint. Appliance of this types are effective but requires detailed dental knowledge and skeletal models of splint construction. The splints are fabricated by specially educated physician with dental training, dental professional or dental laboratory.

Bonded Modified Orthodontic Brackets This method is used in patient with minimal displaced fractures patient with good oral hygiene. This require a help of orthodontic brackets which are applied on a teeth then applying intermaxillary elastic bends. The orthodontic brackets are prepared in maxofacial laboratory. This technique requires complete elimination of moisture, this is not applicable in cases where there is intraoral bleeding.

48 / Fracture Mandible

Nonrigid Osteosynthesis      

Transosseous wiring Circumferential wiring External pin fixation Bone clamps Trans fixation with kirschner wires (K wires) These fixation been non rigids require intermaxillary fixation.

Semirigid Osteosynthesis   

Mandibular plate Dynamic compression plate Lag screw plate

Rigid Osteosynthesis   

Reconstruction plate Locking plate Three-dimensional sturd

Miniplates Mini plates are available in various shapes and lengths but can only be used with non-locking screws. For mandible 2.5 mm or 2 mm plate are usually used. They are most commonly used for fracture mandible.

Dynamic Compression Plates Screws are need to be inserted bicortically when using plates.

Indications Simple fractures mandible with excellent bony buttressing, are preffered for dynamic plate compression plate.

Contraindications Compression plating is contraindicated when there is not good bony buttressing at the fracture site, as is seen in atrophic edentulous mandible fractures, defect fractures, comminuted fractures, and other complex mandibular fractures.

General Treatment of Fracture Mandible / 49

It is also contraindicated in:  Simple fractures with an extreme oblique pattern (sagittal fractures)  Fracture mandible with no good bony buttress  Atropic mandibular fracture  Edentulous fracture mandible  Defect fractures  Communited fractures  Other complex fractures

Compression Plating Principle As the eccentrically placed compression screws are tightened, the head moves down the ramp and the bone is compressed together. Diagrams showing two eccentrically screw inserted but not fully tightened screws.

Fig. 8.7: The left screw is fully tightened and thereby narrowing the gap

Fig. 8.8: Tightening the right screw finally compresses the fracture toward each other these compression screws are bicortical in nature

50 / Fracture Mandible

Compression Plating Technique The compression plate is adapted by slightly over bending and eccentric hole is drilled on either side of the fracture.

Fig. 8.9: Dynamic compression plate

Overbending The plate must be overbend slightly to close the lingual cortex. As compression screws are tightened, the slightly overbent plate closes the lingual gap. If the plate is not slightly overbent, the buccal cortex will be well aligned but a gap remains at the lingual cortex

Eccentric Drilling for Compression

Fig. 8.10: Gap at lingual cortex if plate not overbend

There are two drill guides used with compression plating. The yellow drill guide is used for eccentric hole placement. The green drill guide is used for neutral hole placement. To drill eccentrically, the arrow on the yellow end of the drill guide must point towards the fracture. The number close to the arrow shows the maximal possible amount of bone movement upon screw insertion. To place an eccentric hole, the proper gold drill guide must be used and the arrow must point toward the fracture. Once both the eccentrically placed screws are tightened, the fracture is compressed. There is no need to compress the fracture additionally so the remaining screws are placed in a neutral position. The appropriate green drill guide is used to place the neutral screws Screws used for the compression plate are bicortical in nature.

General Treatment of Fracture Mandible / 51

Option for Off-Angle Drilling There are times when off-angle drilling is necessary to avoid anatomic structures such as tooth roots. Although the hole does not have to be drilled at 90° to the bone it should not enter the fracture, and it should not be angled in such a way that it interferes with the adjacent screws.

Fig. 8.11: Off-Angle drilling

Lag Screws and Technique Principles This technique, advocated by niederdellmann et al is not commonly practice because it is difficult to excecute and it is easy to achieve in adequate fixation.

Fig. 8.12: Lag screw principle

Lag Screw Versus Lag Technique Lag screws and the lag technique compress the fracture fragments together. There are two methods by which to achieve this. True lag screws (as illustrated here) have threads only on the terminal end of the screw. Therefore, when inserted across a fracture, the threads of the tip of the screw engage the far cortex and the head of the screw engages the near cortex, causing compression of the fracture fragments upon tightening. True lag screws are not available. Instead, a lag technique is used. The lag technique involves overdrilling the near cortex to the size of the external diameter of the screw. When the screw is inserted, it glides through this overdrilled hole and the threads only engage the far cortex. As the screw is tightened the head of the screw engages the near cortex and the fracture fragments are compressed together. If the near cortex is not overdrilled, the threads of the screw will engage both near and far cortices preventing compression of the fracture fragments.

Indication In parasymphysis/symphayis oblique fracture.

52 / Fracture Mandible

Contraindication—Comminuted Fractures Because lag screw technique compresses the fracture fragments together, the use of this technique is contraindicated in comminuted fractures.

Lag Technique The first step is to determine that the drill is aligned perpendicular to the bevel of the fracture. The near cortex is perforated using a drill that is the same diameter as the external diameter of the screw. The gliding hole is taken to the fracture site or slightly beyond. Fig. 8.13: Drill the near cortex to the external diameter of screw For example, when using a plating system 2.4, the external diameter of the screw is 2.4 mm. The drill used to drill the near cortex is therefore 2.4 mm. It may be difficult for the surgeon to determine when the fracture site has been reached with the gliding hole. It may be advantageous to drill past the fracture site rather than stay short of the fracture site. If the gliding hole is short of the fracture, Fig. 8.14 compression of this fracture will not be obtained with lag screw technique. When drilling obliquely to the surface of the bone, the point of the drill can easily slide along the bone. It is helpful to first orient the drill perpendicular to the near cortex to create an initial hole before reorienting the drill perpendicular to the bevel of the fracture. A special drill guide is used to Fig. 8.15 drill through the far cortex. This drill Figs 8.14 and 8.15: Drill the far cortex to guide has an extension on its tip that the inner diameter of the screw using is the same diameter as the external “centering” drill guide

General Treatment of Fracture Mandible / 53

diameter of the screw. The drill guide snugly fits into the hole previously drilled through the near cortex. It is imperative that the fracture fragments be properly reduced prior to drilling through the far cortex.. The drill guide centers the drill that will be used to drill the far cortex with the hole through the near Fig. 8.16: Special drill guide used to drill cortex. This drill has the diameter for far cortex that is similar to the inner diameter of the screw. For instance, when using a 2.4 mm screw, a 1.8 mm drill is used to drill the far cortex. When drilling, it is difficult to irrigate the tip of the drill. Therefore, it is imperative that the drill be repeatedly withdrawn so that the irrigant effectively cools the tip of the drill and washes away bony debris.

Determine the Screw Length A depth gauge is used to determine the screw length. It is important to assure that the tip of the screw completely engages the far cortex. Because self-tapping screws have a point on their tips, it is important that the tip of the screw completely exits the far cortex so that the screw Fig. 8.17: Determine screw length threads engage completely. Therefore, it is always better to select a screw that is slightly longer than the measurement recorded with the depth gauge.

Screw Insertion The proper length screw is inserted and tightened. One should observe the near cortex as the screw is tightened to assure that cracking or crazing does not occur from overtightening.

Fig. 8.18: Screw insertion

54 / Fracture Mandible

Countersink Near Cortex A countersinking tool is used to create a platform in the near cortex, these countersinking should be done by hand instrumentation. Use of power instruments can easily penetrate the outer cortex. The hole created by the countersinking tool provides a platform into which the undersurface of the head of the screw will intimately contact when the screw is tightened. Failure to perform proper countersinking causes an Fig. 8.19: Improper countersinking eccentric force which can displace the fracture fragments upon tightening the screws. The medullary bone offers no resistance to the head of the screw. Therefore, it is imperative that countersinking does not remove all of the cortical bone around the circumference of the head of the screw. Otherwise, as Fig. 8.20: Head entering the medullary space the screw is tightened its head will enter the medullary space and provide no compression of the fracture fragments Properly applied lag screw resulting in interfragmentary compression.

Locking Plates Locking plates are available in a variety of plate thicknesses (referred to as profile). All locking plates can hold either locking head screws or standard (nonlocking) screws. Locking plates available are:  Small profile locking plate  Medium profile locking plate  Large profile locking plate  Extra-large profile locking plate They are also available in multiple shapes to meet a variety of clinical applications.

General Treatment of Fracture Mandible / 55

The threaded head of the 2.0 mm locking head screws is conical. It is therefore possible to insert locking head screws at small angles. A threaded drill guide is not necessary.

Locking Reconstruction Plates

Fig. 8.21: Locking reconstruction plate

There is only one thickness of the locking reconstruction plate. However, there are multiple plate configurations to meet a variety of clinical applications. The threaded head of the 2.4 mm locking head screws is cylindrical. Therefore, a threaded drill guide is mandatory to assure the correct perpendicular insertion of 2.4 mm locking head screws. Angulation is not possible. Reconstruction plates are used for load bearing osteosynthesis of mandibular fractures

Locking Versus Nonlocking Plates—Advantages to a Locking Plate/Screw System There are several advantages to a locking plate/screw system: Locking plate and screw systems have advantages over the conventional screw systems. Conventional plate/screw systems require precise adaptation of the plate to the underlying bone. Without this intimate contact, tightening of the screws will draw the bone segments toward the plate, resulting in alterations in the position of the osseous segments and the occlusal relationship. Locking plate/screw systems offer certain advantages over other plates in this regard. The most significant advantage may be that it becomes unnecessary for the plate to intimately contact the underlying bone in all areas. As the screws are tightened, they “lock” to the plate, thus stabilizing the segments without the need to compress the bone to the plate. This makes it impossible for the screw insertion to alter the reduction.

56 / Fracture Mandible

Another potential advantage in locking plate/screw systems is that they do not disrupt the underlying cortical bone perfusion as much as conventional plates, which compress the undersurface of the plate to the cortical bone. A third advantage to the use of locking plate/screw systems is that the screws are unlikely to loosen from the plate. This means that even if a screw is inserted into a fracture gap, loosening of the screw will not occur. Similarly, if a bone graft is screwed to the plate, a locking screw will not loosen during the phase of graft incorporation and healing. The possible advantage to this property of a locking plate/screw system is a decreased incidence of inflammatory complications from loosening of the hardware. It is known that loose hardware propagates an inflammatory response and promotes infection. For the hardware or a locking plate/screw system to loosen, loosening of a screw from the plate or loosening of all of the screws from their bony insertions would have to occur. Locking plate/screw systems have been shown to provide more stable fixation than conventional nonlocking plate/screw systems. Locking plates

Unlocking plates

Rigid fixation

Semi rigid fixation

Does not require precise adaptation

Requires precise adaptation

Do not disturb the underlying bone perfusion

It do disturb the underlying bone perfusion

Decrease incident of complication like loosening of screw and infection

Increase incident of complication like loosening of srews and infection

More stable fixation

Less stable fixation

Screw insertion does not affect the reduction of the segment

Screw insertion does affect the reduction of the segment

Locking Head Screws The locking plate has a corresponding threaded plate hole.

Fig. 8.22: Threaded plate hole and threaded screw head

General Treatment of Fracture Mandible / 57

During insertion the locking head screw engages and locks into the threaded plate hole.

Fig. 8.23: Screw should be perpendicular to the plate

Conventional Screws If necessary the threaded plate hole also accepts nonlocking screws, which permit greater angulation.

Biomechanics Conventional Screws With the conventional technique, the tightening of the screws presses the plate against the bone. This pressure generates friction, which contributes significantly to primary stability. Loading forces are transmitted from the bone to the plate, across the fracture and back into the bone. Friction between plate and bone is necessary for stability using conventional screws.

Fig. 8.24: Friction between bone and plate

Fig. 8.25: Loading force transmitted from bone-to-plate and then plate-to-bone

Locking Head Screws However, with the locking head screws engaged in the plate, the plate is not pressed onto the bone. This reduces interference to the blood supply to the bone underlying the plate.

Fig. 8.26: No pressure on bone-locking system

58 / Fracture Mandible

Loading forces are transmitted directly from the bone to the screws, then onto the plate, across the fracture and again through the screws into the bone. Friction between plate and bone is not necessary for stability. The plate and screws provide adequate rigidity and do not depend on the underlying bone (load bearing osteosynthesis) when using a locking reconstruction plate 2.4. On each side of the fracture, the Fig. 8.27: Loading force transmitting directly from bone-to-screw then to plate and then screws are locked into the plate as screw-to-bone well as into the bone. The result is a rigid frame construct with high mechanical stability (internal external fixator).

Primary Loss of Reduction Conventional Plate System When using conventional plates and screws it is essential to contour the plate precisely to the bone surface. When using conventional plate and screws the plate must be precisely adapted to the bone, otherwise the tightening of the screws will lead to a primary loss of reduction in (Fig. 8.28) the plate is not well adapted to the outer cortex in lower diagram (Fig. 8.29) shows that when the screws are inserted, the bone will be pulled to the plate, causing malreduction of the fracture.

Fig. 8.28: Precise adaptation of plate

Fig. 8.29: Imperfect adaptation leads to malreduction of fracture

Locking Plate System When using a locking plate/screw system, the plate does not have to be precisely adapted to the bone. When tightening a locking head screw, the screw will not cause a primary loss of reduction as it tightens into the threaded plate hole and will not draw the bone fragments to the plate.

General Treatment of Fracture Mandible / 59

Secondary Loss of Reduction Conventional Plate System In conventional plate systems, screw loosening may lead to loss of reduction.

Locking Plate System In a locking system, screw loosening rarely occurs because the screw head is locked to the plate.

Universal Fracture Plate 2.4 They are designed to be used with bicortical screws. Universal fracture plates offer more biomechanical stability than DCP 2.4 plates

Load-Baring Osteosynthesis (stabilization by splinting) The plate bears the forces of function at the fracture site. This is accomplished with a locking reconstruction plate. Clinical uses are the management of atrophic edentulous fractures, comminuted fractures, defect fractures, and other complex mandibular fractures.

Load-Sharing Osteosynthesis

Fig. 8.30: Load-bearing osteosynthesis

Fig. 8.31: Lag screw load-sharing osteosynthesis

60 / Fracture Mandible

General Consideration Stability at the fracture site is created by the frictional resistance between the bone ends and the hardware used for fixation. This requires adequate bony buttressing at the fracture site. Examples of loadsharing osteosynthesis include lag screw fixation technique and compression plating. Load-sharing osteosynthesis cannot be used with defect fractures or comminuted fractures, due to the lack of bony buttressing at the fracture site. Another form of load-sharing osteosynthesis is the miniplate fixation technique popularized by Champy. This is also known as functionally adequate fixation or semirigid fixation.

Fig. 8.32: Minihole plate load sharing osteosynthesis

Ideal Lines of Osteosynthesis Champy popularized the treatment of Fig. 8.33: Champy’s line mandible fractures with miniplate fixation along the ideal lines of osteosynthesis. This is a form of load-sharing osteosynthesis to be applied in simple fracture patterns having an acceptable amount of bone stock.

Different Levels of Force Distribution In the load-bearing situation the plate assumes all the forces, in the loadsharing situation there are different levels of force distribution between the plate(s) and the bone.

Load-Bearing In load-bearing fixation the plate assumes 100% of the functional loads. This is an example of load-bearing osteosynthesis for the treatment of a defect fracture in the angular region. The osteosynthesis assumes all the masticatory loads while the bone graft matures and consolidates in a protected environment.

Fig. 8.34: Load-bearing osteosynthesis

General Treatment of Fracture Mandible / 61

Intermediate Load-Sharing Situation Intermediate load-sharing situation where the osteosynthesis and the bone share the functional loads almost equally. This is an example of load-sharing osteosynthesis for the treatment of a simple angular fracture. The two miniplates share the loads with the bone in an anatomical region where the bone stock and force distribution are not ideal.

Fig. 8.35: Intermediate load-sharing osteosynthesis

Ideal Load-Sharing Situation Ideal load-sharing situation where the bone assumes most of the functional loads. In this example, a simple mandibular body fracture was considered suitable for a single miniplate osteosynthesis in the neutral zone because of the good bone stock and optimal force distribution.

SUMMARY

 Aim of treatment of fracture mandible is to reduce the fracture segment and fix it so that normal anatomical relationship can be maintained.  Atmost precaution to be taken to preserve the blood supply of the bone and the soft tissue by careful handling and reduction technique.  Attempt should be made for early and safe mobilization and rehabilitation of the patient.  There are many methods of closed reduction but arch bar application is more commonly used.  Period of immobilization 3–4 weeks for young adult with angle fracture + 1 week if teeth is in a fracture line + 1 week for fracture of parasymphysis + 1 or 2 week for age 40 years and above – 1 week for childrens and adolsent  Dynamic compression plates and lag screws are not commonly used in fracture mandible.  Reconstruction plate, miniplate are most commonly used.  Rigid osteosynthesis are: – Reconstruction plate – Locking plates – Three-dimensional sturd.

62 / Fracture Mandible

 Semirigid osteosynthesis are: – Mandibular plate – Dynamic compression plate – Lag screw plate  Nonrigid osteosynthesis are: – Transosseous wiring – Circumferential wiring – External pin fixation – Bone clamps – Transfixation with K wire  Load sharing osteosynthesis are: – Lag screw – Dynamic compression plate – Miniplates  Load-bearing osteosynthesis are: – Reconstruction plate – Locking plates  Locking plates are better than unlocking plates.

Anesthesia for Fracture Mandible / 63

9

Anesthesia for Fracture Mandible

All closed reduction of fracture mandible can be done under local anesthesia. While open reduction is preferably done under general anesthesia. Young cooperative patient with simple, undisplaced fracture open reduction can be tried under local anesthesia. We prefer to apply arch bar under local anesthesia and in case of open reduction patient is then further given general anesthesia. Application of arch bar is better done in local anesthesia. As this require cooperation of the patient in terms of mouth opening and moving the tongue in an appropriate direction, thus this prevents excess retraction and a pressure on a tongue which is required if IMF is done in general anesthesia. Thus this cause decrease edema of tongue and cheek.

General Anesthesia The anesthesia is same as all routine procedures but few special precautions need to be taken. Procedure - Reduction and fixation of fracture mandible Time - 2 to 3 hours depending upon the severity Postoperative pain - ++ Position - Supine with head up tilt with head ring, in case of extraoral approach a shoulder should be kept Blood loss - Variable Intubation technique - Nasal tube (blind or guided) and IPPV Fibreoptic intubation may be required.

Preoperative   

 

It is same as all routine anesthesia Careful assessment for associate injury should be done Make a meticulous assessment of airway, there may be several trismus and soft tissue swelling Explain the patient about postoperative events like mouth closure in a brief Assess nostril patency

64 / Fracture Mandible 





Check for evidence of basal skull fracture and CSF leak, which make nasal intubation contraindicated In a case of severe trismus and where postoperative edema may be anticipated, tracheostomy should be considered Submantle intubation should be considered in a case of pan facial trauma

Perioperative 





 

 



Trismus make intubation look potentially difficult preoperatively as the mouth opening is markedly limited due to the muscle spasm, hematoma, pain, but this tend to relax following induction Nose should be packed with 4% lignocaine with adrenaline or otrivin nasal drop should be used Bilateral mandible fractures can cause increase anterior jaw displacement after induction but airway maintenance by face mask may not always be easy due to increase jaw movement, swelling A rapid sequence induction with suxa-methonium is appropriate A marked swelling may make intubation difficult and awake fibreoptic intubation may be required Gas induction is often difficult due to pain while applying the face mask Make sure that the patient when comes out from anesthesia should not be sedated and should be completely awake from the anesthesia If throat pack is placed around the tube should be removed before the application of wires.

Postoperative   



Observe the patient for sometime in a recovery before sending it to the ward Start humidified oxygen Always keep a wire cutter and a suction machine beside the patients bed (to cut the wires in a case of emergency) Shift the patient with nasopharyngeal airway to the ward.

Local Anesthesia Two percent lignocaine with adrenaline is used for local anesthesia. In case of hypertension and other contraindication a plain lignocaine can be used. In case long duration of anesthesia is required long acting local anesthesia (bupivacaine, ropivacaine, and tetracaine can be used). But 2% lignocaine with adrenalin gives enough duration of anesthesia for arch bar application, so long acting is not usually required.

Anesthesia for Fracture Mandible / 65

Dosage The permission level of plain lignocaine is 4 mg/kg body weight and for 2% lignocaine with adrenalin is 7 mg/kg body weight and for bupivacaine is 2 mg/ kg body weight.

Area of Infiltration For upper jaw anesthesia we need: 1. Posterosuperior alveolar nerve block 2. Middle superior alveolar nerve block 3. Anterosuperior alveolar nerve block (infraorbital nerve) 4. Greater palatine nerve block 5. Incisive foramen nerve block

A: Area anaesthetized by posterosuperior alveolar nerve block

B: Area where local anesthesia is deposited C: Area from where anesthesia is for superior alveolar nerve block injected Fig. 9.1

66 / Fracture Mandible

Posterosuperior Alveolar Nerve Block   

    

26 number short needle is used Orient the bevel of the needle towards bone Partially open the patients mouth, pulling the mandible to the side of injection Retract the patients cheek with your finger Insert the needle into a height of mucobuccal fold over second molar Advance the needle slowly in upward, inward and backward direction Slowly advance to the soft tissue No resistance is filled, if resistance is felt withdraw the needle slightly and change the direction and re-advance again.

Goal Goal is to deposit local anesthesia close to the PSA nerve located posterior superior and medial to the maxillary tuberosity.

Middle Superior Alveolar Nerve Block  



26 number short needle used Area of insertion, height of muccobuccal fold above the second premolar buccal fold Aspirate and if no blood then deposit 0.9–1 ml solution.

Anterosuperior Alveolar Nerve Block (Infraorbital Nerve Block) 

Nerve anesthetized 1. Anterosuperior alveolar 2. Middle superior alveolar 3. Infraorbital nerve

Technique   

Target area—infraorbital foramen (below the infraorbital notch) Landmark—muccobuccal fold, infraorbital notch, infraorbital foramen Area of insertion—height of muccobuccal fold directly over first premolar.

Procedure  

Feel for infraorbital notch Move your fingers downward from the notch applying gentle pressure to the tissue

Anesthesia for Fracture Mandible / 67

A: Area where local anesthesia is deposited for middle superior alveolar nerve block

B: Area from where anesthesia is injected

C: Area anaesthetized by middle superior alveolar nerve block Fig. 9.2





  



The bone immediately inferior to the notch is convex, this represents the lower border of orbit and a roof of infraorbital foramen As your finger continous inferiorly a concavity is felt, this is infraorbital foramen Maintain your finger on the foramen or mark the skin at the site Retract the lips, pull the tissue in muccobuccal fold Insert the needle into the height of muccobuccal fold over the first premolar with the bevel facing bone Reach to your required site

68 / Fracture Mandible

A: Area which is anaesthetized by infraorbital nerve block

B: Area where local anesthesia is injected for infraorbital block

C: Area where local ansethesia is deposited

Fig. 9.3  

Aspirate and if no blood slowly deposit 1 ml in a target area One can feel that solution is deposited beneath the fingers if needle is in a right plane.

Greater Palatine Nerve Block 



Target area—greater palatine nerve as it passes anteriorly between the soft tissue and bone of the heart palate Landmark—a greater palatine foramen and junction of maxillary alveolar process and palatine bone

Anesthesia for Fracture Mandible / 69

A: Area where greater palatine foramen is located

B: Area which is blocked by greater palatine block Fig. 9.4



Part of insertion—advance the syring from the opposite side of the mouth at the right angle to the target area.

Procedure 





Feel for depression of greater palatine foramen with the help of cotton swab and a finger The foramen is located distal to second molar but it may be either anterior or posterior to its usual position Inject in the foramen area around few drops.

70 / Fracture Mandible

Lower Jaw Infiltration 1. Inferior alveolar nerve block 2. Buccal nerve 3. Mental nerve

Inferior Alveolar Nerve Block   

Landmark—coronoid notch (greater concavity of anterior border of ramus) Ptrygomandibular raphe Occlusion plane of mandibular posterior teeth

A: Area anesthetized by infra-alveolar nerve block

B: Area from which anesthesia is given

C: Area where infra-alveolar nerve is located

Fig. 9.5

Anesthesia for Fracture Mandible / 71

Procedure  

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

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A finger tip is kept in a coronoid notch An imaginary line extended posterior from the finger tip in a coronoid notch to the deepest part of the pterygomandibular raphe This imaginary line should be parallel with the occlusal plane of the mandibular molar teeth The needle inserted anteroposterior distance from the coronoid notch back to the deepest part of the pterygomandibular raphe The finger on the coronoid notch is used to pull the tissue laterally, stretching them over the injection side making them taut and for better visibility and to be less traumatic.

Buccal Nerve Block 

Landmark

— External oblique ridge — Muccobuccal fold

A: Area anesthetized by buccal nerve block

B: Area where local anesthesia is deposited Fig. 9.6

72 / Fracture Mandible

Procedure 



A 25 gauge 1 inch long needle is inserted either in retromolar triangle area or buccalmuccosa just distal to mandibular third molar area 0.5 ml of local anesthesia is injected

Mental Nerve Block 

Landmark

— Mandibular premolars — Muccobuccal fold

A: Location of mental foramen

B: Area in which local anesthesia is injected for mental nerve block

C: Area anesthetized by mental nerve block Fig. 9.7

Anesthesia for Fracture Mandible / 73

Procedure 

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A 24 gauge needle with 1 inch length is inserted in muccolabial fold in between two premolar directing downward and anteriorly after retracting the cheek It contacts the bone at the level of apex at the second premolar anterior to it After aspiration, 0.5 ml is slowly injected. SUMMARY

 Do intermaxillary fixation under local if patient is co-operative.  All fracture mandible which require open reduction better to operative in general anaesthesia.

74 / Fracture Mandible

10

Specific Treatment of Fracture Mandible

Although many methods of osteosynthesis has been described but most practised, easy, reliable method of osteosynthesis is miniplate osteosynthesis. Dynamic compression plate osteosynthesis and lag screw osteosynthesis is not widely practised. Nonrigid fixation is seldomly done.

Closed Reduction Intermaxillary fixation application with arch bar:  Simple technique  Indicate for simple undisplaced fracture.

Miniplate Osteosynthesis Advantages a. b. c. d. e.

Not bulky and thick like dynamic compression plate Not perfect adaptation required Insertion of screw are easier Gives good stability to the fracture line Available in titanium as well as stainless steel material.

Champy’s Lines of Osteosynthesis Champy’s and co-worker after careful considering the biomechanics of mandible have described Osteosynthesis line for placing the miniplate in the mandible. A line drawn at the base of the alveolar process corresponds to the line of tension and a miniplate and a screw can be fixed along this line. In parasymphysis region another line is drawn to neutralize the tension force.

Fig. 10.1: Champy’s line

Specific Treatment of Fracture Mandible / 75 

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Behind the mental foramen only one plate should be applied, immediately below the dental root and above the inferior alveolar nerve. Between the two canines and in front of mental foramen another plate near the lower border of mandible is applied in addition to the upper plate.

Fig. 10.2: Minihole plate

Technique This miniplates are around 0.9 mm thick and 6 mm wide. The difference between holes are standardized. The screws available are from 5 to 15 mm in length. The diameter of the screws is 2 mm. Screw of 6 or 8 mm in length are usually used in mandible. The screws are self-tapping.

Fig. 10.3: Screw driver and screw   



   

The plate is bended first so that they can be adapted to bone. 1.5 mm drillbit is used to create a hole almost perpendicular to the plate. Eccentric drilling or repeated insertion of drill produce unfavorable hole thus diminishing the grip of the screw. During drilling continues liquid cooling is necessary to avoid thermal necrosis. A giveway indicates penetration of drill in a cortical bone. Then screw is inserted near the fracture side and gradually tightened. This same procedure is carried out for insertion of screw in all the plates. The inferior alveolar nerve region is considered as the neutral zone of the mandible. Avoid plate and screw fixation in this area that would damage the nerve.

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Basic treatment of any simple fracture mandible is application of load sharing osteosynthesis plates (mini plate most commonly used along the Champy’s line). a. Symphysis fracture and parasymphysis fracture Various options are: A. Symphysis fracture B. Parsymphysis fracture C. Mini plate + dynamic plate osteosynthesis (load-sharing osteosynthesis) D. Two miniplate osteosynthesis (most preferred and practised load-sharing osteosynthesis) E. Lag screw osteosynthesis (load-sharing osteosynthesis).

B A

D C

E Fig. 10.4

Specific Treatment of Fracture Mandible / 77

b. Fracture of angle and ramus  A single monocotical miniplates applied on the external oblique line is enough for simple angle fracture  Fracture between canine and angle (body) can be stabilized by superior border plating along the champy line.

Fig. 10.5: Fracture at angle, plate at external oblique ridge

Basic treatment of any complex fractures (comminuted fractures, infected fractures, loss of bone fractures) is application of larger plates (load-bearing osteosynthesis). A. Complex symphysis and parasymphysis fracture

Fig. 10.6A: Comminuted fracture of parasymphysis

Fig. 10.6B: Reconstruction plate (loadbearing osteosynthesis) at the inferior border to neutralize the tension and the compression force + a arch bar (Torsional bend) is used to neutralize the rotational force

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Fig. 10.6C: Basal triangle fracture of parasymphysis area

Fig. 10.6D: Reconstruction plate (loadbearing osteosynthesis) at a inferior border + miniplate (load-sharing osteosynthesis) at the superior border

Fig. 10.7A: A triangular base fracture at the angle of mandible

Fig . 10.7B: Miniplate (load-sharing osteosynthesis) at the external oblique line + reconstruction plate (load-bearing osteosynthesis) at the inferior border

Fig. 10.7C: Comminuted fracture of angle and body

Fig. 10.7D: Reconstruction plate (loadbearing osteosynthesis) at the inferior border + miniplate (load-sharing osteosynthesis) at external oblique line and at the body

Specific Treatment of Fracture Mandible / 79

Mandibular Condyle Fracture Classification of condyle fractures a. Fracture of head of condyle—simple or comminuted fracture b. Fracture of neck of condyle—simple or incomplete fracture without any displacement and complete fracture of neck of condyle with displacement c. Subcondylar fracture—low and high d. Malunited fracture. The management of mandibular condyle fracture is very much important especially in children because this can laed to disturbance of mandibular growth pattern or even ankylosis of temporomandibular joint. This is the most overlooked and least diagnosed side of fracture.

Treatment The aim of treatment of condylar fracture is to reestablish the anatomical relationship for providing good function and growth on long term basis. a. Fracture of head of condyle The intracapsular fracture of head of a condyle is rare and should be treated conservatively by intermaxillary fixation for a period of 2 to 4 weeks followed by restoration of function. Severe comminuted fractures of the condyle are treated by condylectomy especially in unilateral cases. In case of children, costochondral grafts should be given to replace the lost condyle. Subcondylar fractures These are the fractures below the neck of the condyle. These fractures are classified as:  High condylar fracture  Low condylar fractures

Fig. 10.8

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Fig. 10.9

These can be treated either by conservative approach or surgically depending upon the amount of displacement. Conservative approach is advocated in condylar fractures without any displacement, condylar fracture with little displacement and slight overriding in young children or subcondylar fracture, which are slightly displaced.

Fracture of Neck of Condyle Undisplaced fracture should be treated conservatively, however, grossly displaced fracture open reduction may be required.

Specific Treatment of Fracture Mandible / 81

Open Reduction In grossly displaced condyle fracture where reduction cannot be achieved by conventional method there is a fear of future dearrangement or ankylosis, an open reduction is indicated. The indications are:  Cases of condyle fracture with vertical overriding  Cases in which normal occlusion by manipulation or traction cannot be achieved  Cases of gross displacement especially bilateral condyle fracture  Cases in which condyle fracture interfere with jaw movement  Cases in which condyle are partially fused in a wrong position The condyle is surgically approached by preauricular approach or by submandibular, retromandibular approach. The fracture is reduced and is fixed by either by interosseous wiring or by monocotical miniplates.

Fracture of Coronoid Process This account for 1% of fracture, most of the coronoid fractures do not require any treatment. Cases in which coronoid hinders with opening of mouth, treatment is advised. This coronoid fragment is fixed by interosseous wiring or by mini plate. If reduction is not possible and function is impaired then coronoid process is removed.

Mistakes Common mistakes observed in treatment of rigid fixation:  Poor reduction of fractures  Interposition of tissue between the fracture line  Poor alignment of fractured segment  Insufficient screw placement  Poor plate bending  Poor or lose application of intermaxillary fixation.

Tips 

 

Soft tissue in between the fracture line should be removed as proper allignment cannot be attended. Nonhealing can occur if soft tissue is placed between fractured fragment. Use of drill sleeve provide protection to soft tissue. Drill bit used should be 0.5 mm less than screw size. For example, if 2 mm screw or plate is used 1.5 mm drill bit is used to make hole.

82 / Fracture Mandible 

  

Due to drilling heat is generated, this heat can cause bone necrosis and early screw loosening so cooling by putting saline over the drill bit. Avoid damage to mental nerve, tooth root, inferior alveolar canal. Proper bending of a plate should be done. A space of about 5 mm should be kept between two plates. SUMMARY

 In case of simple, undisplaced fracture and no expertise available or condition of patient does not allow general anesthesia; close reduction of fracture mandible most preferably by arch bar method (IMF) is suitable.  In cases of parasymphysis and symphysis fracture in addition to lower border miniplate application a superior border miniplate is also applied to combat torsional force.  A miniplate with two hole on either side of fracture mandible is ideally fixed.  Champy’s line of osteosynthesis give idea of sight of application of plates in various areas.  In simple undisplaced fracture load sharing plate (mini plate) to be used.  In grossly displaced, infected, loss of segment fracture mandible reconstruction plate should be ideally used.  All cases of undisplaced condyle fracture can be treated by closed reduction.  Open reduction in a condyle fracture is indicated in cases where by manipulation or traction the fracture segment is not reduced or cannot be brought into normal occlusion.

Surgical Approaches / 83

11

Surgical Approaches

Surgical Approaches 1. Extraoral 2. Intraoral 3. The use of existing lacerations

Extraoral Approach Submental Approach The submental approach is used to treat fractures of the anterior mandibular body and symphysis. These fractures can usually be approached and treated intraorally. However, depending on the difficulty or severity of the fracture, and/or the presence of a laceration suitable, an extraoral approach via the submental route may be indicated. Advantages  Lingual surface of the mandible can be easily inspected to assure optimum reduction of fracture in this segment.  There is no major neurovascular structure in this area.  Scar is not that visible

Fig. 11.1: Variations in incision: (A) Following curvature of anterior mandible, (B) Hidden in submental skin crease

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Dissection  Carry the incision through the skin and subcutaneous tissues to the platysma muscle.  The platysma muscle must be divided.  There may be a natural separation of the muscle in the midline region. Additionally the platysma muscle can become very thin in this region.  Dissection is carried out to the inferior border of the mandible. The periosteum is incised sharply and the flap is elevated to expose the anterior surface of the symphysis. Wound closure  The wound is closed in layers to realign the anatomic structures and to eliminate dead space.  The periosteum and platysma muscle should be closed in different layers.  Option: bilateral extension Submental extension The submental incision can be extended laterally to encompass both the right and left mandible by degloving the entire lateral surface of the mandible in the same way as in the submandibular approach. This may be necessary in complex fractures such as comminuted, atrophic, and severe bilateral fractures. To approach complex mandibular fractures the surgeon essentially combines a right and left submandibular incision with a submental one. The inferior border of the mandible is marked along with the planned skin incision.

Submandibular Approach In 1934–risdon describe this technique.

Fig. 11.2: Various submandibular incisions

Surgical Approaches / 85

Principles This approach is selected for fractures of the mandibular body and angle regions unsuitable for intraoral treatment. This applies to more difficult fracture patterns such as comminuted, atrophic, and defect fractures in order to allow optimal manipulation of the fragments, good control of the lingual cortex and inferior border, and the application of the selected hardware. Variations The incision can either be parallel to the inferior border of the mandible atleast 2 cm below the angle of the mandible (A) or be placed in an existing skin crease (B) for maximum cosmetic benefit. If using skin creases for the incision, the orientation of the scalpel blade is parallel to the skin creases. Subplatysma flap elevated. Neurovascular structures The main neural structure is the marginal mandibular branch of the facial nerve (CN VII). The facial artery and vein are also encountered during this dissection. They are commonly located 1 cm below the angle of the mandible. This neurovascular structure are identified by Holder Martins method in which facial vessels are identified and they are retracted so that they are safe in the flap. The dissection is carried out through the deep cervical fascia. The muscle, periosteum and other soft tissues are retracted superiorly to expose the body, angle and the ramus of the mandible. Then the fracture line is identified.

Retromandibular Approaches In 1967, Hinds and Girrotti first described this approach. Skin incision Incision is made 3 cm above the submandibular incision The incision is carried curving behind the angle of mandible Use of normal saline for infilteration is employed for maintenance of the plane and in a cases where nerve stimulator has to be used.

Fig. 11.3: Retromandibular approach

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Use of 2% lignocaine with adrenalin can be used for vasoconstrictor effect. Use of 2% local anesthetic may impair the function of the marginal mandibular nerve and prevent the use of a nerve stimulator during the surgical procedure. Subplatysma flap elevated Superior subplatysmal dissection would expose the underlying marginal mandibular branch of the facial nerve (CN VII). By ligating and dividing the facial artery and vein and then retracting the vessels superiorly, the marginal mandibular branch of the facial nerve remains included in the superior flap and is thus protected. Divide the pterygomasseteric sling and incise the periosteum at the inferior border to expose the fracture site. This expose the body and angle region. For wound closure, the pterygomasseteric sling is closed. The wound is closed in layers to realign the anatomic structures and eliminate dead space. The platysma muscle is closed. A drain may be used if necessary. Principles The retromandibular approaches expose the entire ramus from behind posterior border. They therefore may be useful for procedures involving area on or near the condylar process/head, or the ramus itself. There are two varieties of retromandibular approach used to access posterior mandible. They differ in the placement of the incision and anatomic dissection to the mandible. The transparotid approach has the advantage of close proximity of skin incision to the area of interest. The retroparotid approach has advantage of not dissecting through the parotid gland. The facelift (rhytidectomy) approach can be considered as an alternative to retromandibular approaches. The main anatomic structures in this approach are the main trunk and branches of the facial nerve (CN VII) and the retromandibular vein. Transparotid approach: Skin incision A vertical incision through skin and sub-

the the the the the the

Fig. 11.4: Tranparotid approach skin incision

Surgical Approaches / 87

cutaneous tissue is made, extending from just below the ear lobe towards the mandibular angle. It should parallel the posterior border of the mandible. Dissection The subcutaneous tissue is undermined, exposing the superficial musculoaponeurotic system (SMAS). A vertical incision is made through the SMAS into the parotid gland. Blunt dissection of the parotid gland Bluntly dissect the parotid gland parallel to the direction of the facial nerve branches and towards the posterior border of the mandible. The dissection should be anterior to the retromandibular vein. Branches of the facial nerve may be found during the dissection. A nerve stimulator may be helpful to identify them. They should be mobilized and protected. Once the posterior border of the mandible has been reached, an incision is made through the pterygomasseteric sling. Subperiosteal dissection of the mandibular ramus A periosteal elevator is used to strip the masseter muscle from the ramus. Further dissection superiorly along the posterior border exposes the condylar process. Transparotid approach: Wound closure The wound is reapproximated in layers for anatomic realignment and avoidance of dead space. The parotid gland capsule must be closed tightly to prevent salivary fistula. The SMAS is resuspended. Alternative: Retroparotid approach Principles A frequently used alternative to the retromandibular transparotid approach described above is one in which the parotid gland is lifted rather than dissected through. This requires the incision to be placed more posteriorly which means that exposure of the mandible is more limited. Rather than approaching the mandible from directly over the ramus, it is approached more posteriorly.

Fig. 11.5: Retroparotid approach

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Skin incision An oblique incision through skin and subcutaneous tissue is made, extending from the mastoid process to a point just below the angle of the mandible. Dissection The subcutaneous tissue is undermined, exposing the superficial musculoaponeurotic system (SMAS). An oblique incision is made through the SMAS. The posterior aspect of the parotid gland is identified and dissection continues behind the gland. The gland is lifted off the masseter muscle and retracted anteriorly. Once the posterior border of the mandible has been reached, an incision is made through the pterygomasseteric sling. Subperiosteal dissection of the mandibular ramus A periosteal elevator is used to strip the masseter muscle from the ramus. Further dissection superiorly along the posterior border exposes the condylar process. Wound closure The wound is reapproximated in layers for anatomic realignment and avoidance of dead space. The SMAS is resuspended. A suction drain may be placed.

Preauricular Approach Principles The preauricular approach can be used to access and treat fractures in the mandibular condylar head and neck region. Many surgeons perform temporal mandibular joint (TMJ) surgery and routinely use this incision to access the superior portion of the mandibular condylar process. Neurovascular structures Branches of the facial nerve may be involved in this incision and dissection. The superficial temporal artery and vein are commonly encountered in this surgical approach. The vessels should be conserved if possible. Facelift incision Skin incision Make the incision in a preauricular skin crease. Dissection Locating temporalis fascia.

Surgical Approaches / 89

Carry the incision through the skin and subcutaneous tissues to the depth of the temporalis fascia. The temporalis fascia is a glistening white tissue layer that is best appreciated in the superior portion of the incision. The superficial temporal vessels may be retracted anteriorly with the skin flap (sectioning some posterior and superior branches) or left in place (sectioning frontal branches). Fig. 11.6: Facelift incision The zygomatic arch can easily be palpated at this point of the dissection. The lateral pole of the mandibular condyle can also be palpated. This can be facilitated by having a surgical assistant manipulate the jaw. Incising temporalis fascia Make an oblique incision parallel to the frontal branch of the facial nerve, through the superficial layer of the temporalis fascia above the zygomatic arch. Dissection of the joint capsule Insert the periosteal elevator beneath the superficial layer of the temporalis fascia and strip the periosteum off the lateral zygomatic arch. Dissection will be carried inferiorly to expose the capsule of the TMJ. The frontal branch of the facial nerve is protected within the superficial layer of the deep temporalis fascia. Dissection can be carried inferiorly in a subperiosteal plane to reach the neck of the mandibularcondyle. A disadvantage of this approach is that the surgeon can reach only a limited portion of the condylar neck region. Wound closure If the TMJ capsule has been incised to access the condylar head it must be closed as the first step. The temporalis fascia is closed as the next step. Skin and subcutaneous sutures are placed. A pressure dressing may be placed over this wound according to surgeon’s preference.

90 / Fracture Mandible

The various modification of preauricular incision. a. Rowe modification  Preauricular with temporal extension.  An incision is angled from the point of the attachment of helix upwards and forward at 45 degree lying within the hair bearing area over the temporal region.  This incision allows an extensive flap to be raised and avoid traction injury to upper branches of facial nerve.  Reverse sigmoid shaped incision gives the most satisfactory result by helping to disguise the final scars. b. Blair and ivy  Preauricular incision with an inverted hockey stick incision over the zygomatic arch.  Gives easy access and better stability and facilitated exposure of arch along with the condylar arc. c. Alkayat-Bramley preauricular incision  Alkayat-Bramley preauricular incision along with a (question marked shape) curved temporal extension is advocated mainly for TMJ ankylosis as it gives a wide area of exposure and also facilitates elevation of temporal flap for reconstructive purpose. d. Endaural approach  This approach gives good scar but poor access.  So rarely used. 1. Intraoral approach  Symphysis and body.  Condylar process and ramus In practise intraoral approach is more commonly used. Advantages  Intraoral approach is more rapid than extraoral approach  Avoid external scar  More visualization for horizontal mandible anteriorly Disadvantages  Only labial cortex is visualized  Thus there is a chances of significant gap remaining in the lingual cortex

Surgical Approaches / 91

Intraoral Approach to the Symphysis and Body Vestibular Incisions The intraoral approach is the usual access for simple fractures of the body, symphysis, and angular regions. The approach can be extended posteriorly (dashed line) for better access to the body, angle and ramus regions. In complex fractures including Fig. 11.7: Intraoral incison for comminuted, edentulous, and avulsive symphysis and body fracture fractures requiring the placement of loadbearing reconstruction plates, a extraoral approach may provide better access. Oral contamination is not a contraindication for an intraoral incision.

Mucosal Incision Unless contraindicated, infiltrate the area with a local anesthetic containing a vasoconstrictor. Make an incision through the mucosa in the vestibule. Between the canines the incision is made 10–15 mm away from the attached gingiva in a curvilinear fashion. Posterior to the canine the incision is only 5 mm away from the attached gingiva, staying superior to the mental nerve.

Neurovascular Structures The mental nerve is a branch of the fifth cranial nerve (trigeminal nerve). This nerve provides sensation to the anterior mandibular vestibule, lip and chin. When the incision is extended posterior to the canine teeth, the mental nerve can be damaged. Keep the incision superior to the mental nerve in the body region. Particularly in the extended intraoral approach, care must be taken to protect the mental nerve in the anterior body region.

Surgical Flap Dissection Dissect a mucosal flap that retracts or is lifted (as shown) to expose the surface of the mentalis muscle. The branches of the mental nerve are located just underneath the mucosal flap and must be respected.

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Mentalis muscle dissection The mentalis muscle is incised near the alveolar bone ridge thus creating a stepwise approach which protects the mental nerve. Later, during wound closure the mentalis muscle should be properly reattached.

Fracture Site Exposure Elevate a mucoperiosteal flap to expose the fracture. Extension of Approach Lateral/posterior vestibular incision. The approach can be extended laterally and posteriorly to provide access to the body, angle and ramus regions of the mandible. Right-angled retractors are helpful in this approach.

Wound Closure After thoroughly irrigating the wound and checking for hemostasis the incision is closed. Anteriorly, the mentalis muscle is reapproximated to prevent drooping of the chin tissues. The mucosa is closed with interrupted or running resorbable sutures. An elastic pressure dressing on the chin region helps support the soft tissues and prevent hematoma formation

Intraoral Approach to the Angle

Fig. 11.8: Mucosal incision for angle fracture

Principles Vestibular incisions The intraoral approach is used for the majority of simple angle fractures. Depending on whether or not a third molar is to be extracted, there are two

Surgical Approaches / 93

surgical approaches. Where there is no third molar present, or where one is present but is to be left in place, a purely vestibular incision approximately 5 mm away from the attached gingiva is made (A). When an erupted third molar is to be removed, the incision must incorporate the attached gingiva around the buccal side of the tooth (B, combination of vestibular and envelope incisions). Oral contamination is not a contraindication for an intraoral incision. Restricted access and contamination In complex fractures including comminuted, edentulous, and avulsive fractures that will require the placement of load-bearing reconstruction plates, a transfacial/extraoral approach can provide better access to treat the injury. Tips  Avoid injury to the sensory buccal nerve  Reattach the buccinators muscle to its original position as far as possible Sensory buccal nerve The sensory buccal nerve crosses the upper anterior rim of the mandibular ascending ramus in the region of the coronoid notch. It is usually below the mucosa running above the temporalis muscle fibers. When the posterior vestibular incision is carried sharply along the bony rim, the buccal nerve is at risk of transsection, followed by numbness in the buccal mucosal region. Therefore, to protect the nerve, the posterior dissection is to be extended bluntly as soon as the lower coronoid notch is reached. The photograph shows the sensory buccal nerve. Buccinator muscle The lateral mucogingival vestibular incision transsects the lower attachment of the buccinator muscle. Stripping the mucoperiosteal flap laterally dislocates the lower border of the muscle. To reattach the muscle, the sutures for wound closure in the lateral vestibular should not only be superficial. The suture should catch all layers (mucosa and muscle) as a safeguard for muscle reattachment. Vestibular incision Unless contraindicated, infiltrate the area with a local anesthetic containing a vasoconstrictor. Make an incision through the mucosa in the vestibule approximately 5 mm away from the attached gingiva (in the mucogingival junction), extending up the external oblique ridge. The fracture must be reduced adequately before fixation is applied. The fixation can be either by transbuccal or right-angled instrumentation.

94 / Fracture Mandible

Combination with the transbuccal technique The transbuccal trocar may also assist the surgeon in positioning posterior and inferior screws, sometimes avoiding the need for an extraoral approach. Wound closure of the vestibular incision After thoroughly irrigating the wound and checking for hemostasis the surgeon can close the incision. An elastic pressure dressing covering the angle region helps support the soft tissues and prevent hematoma formation. Wound closure using envelope flap The envelope portion of the flap is undermined with scissors to facilitate tension-free advancement over extraction site. Generally, resorbable sutures are used for this closure. The flap is advanced and closed over the extraction site.

Intraoral Approach to the Condylar Process and Ramus Principles The vestibular incision can be used for standard fracture fixation techniques or in conjunction with endoscopically assisted surgical techniques. The ramus and condyle region can be exposed via an intraoral approach by extending the standard vestibular incision in a superior direction up the Fig. 11.9: Mucosal incision for condyle ascending ramus. The incision can and ramus fracture be altered depending on the area of the ramus/condylar process that needs exposure and treatment. Oral contamination is not a contraindication for an intraoral incision. In complex fractures including comminuted and avulsive fractures that require the placement of load-bearing reconstruction plates, a transfacial/ extraoral approach can provide better access to treat the injury. Tips  Avoid injury to the sensory buccal nerve  Reattach the buccinators muscle to its original position as far as possible

Surgical Approaches / 95

Sensory Buccal Nerve The sensory buccal nerve crosses the upper anterior rim of the mandibular ascending ramus in the region of the coronoid notch. It is usually below the mucosa running above the temporalis muscle fibers. When the posterior vestibular incision is carried sharply along the bony rim, the buccal nerve is at risk of transsection resulting in numbness in the buccal mucosal region. Therefore, to protect the nerve, the posterior incision is to be extended bluntly as soon as the lower coronoid notch is reached.

Buccinator Muscle The lateral mucogingival vestibular incision transsects the lower attachment of the buccinator muscle. Stripping the mucoperiosteal flap laterally dislocates the lower border of the muscle. To reattach the muscle, the sutures for wound closure in the lateral vestibular should not only be superficial. The suture should catch all layers (mucosa and muscle) as a safeguard for muscle reattachment. Reminder: The buccinator muscle belongs to the mimic muscle system and has a unique functional structure allowing for a movement comparable to a peristaltic motion. The deep fibers run in parallel bundles from the modiolus to the pterygomandibular raphe at the level of the occlusal plane (intercalar region) and account for the buccinator mechanism building up a ridge towards the occlusal plane. Its detachment can result in an impaired bolus transport out of the buccal space which is troublesome for the patient. The buccinator is innervated by the motor buccal branch of the facial nerve.

Incision Unless contraindicated, infiltrate the area with a local anesthetic containing a vasoconstrictor. Make an incision through the mucosa in the vestibule approximately 5 mm away from the attached gingiva (in the mucogingival junction), extending up the external oblique ridge.

Exposure of Fracture The lateral surface of the ramus and condylar process is exposed in a subperiosteal plane to visualize the fracture. Right-angled retractors and fiberoptic lighting would facilitate this procedure. The fracture must be reduced adequately before fixation is applied. The fixation can be done either by transbuccal or right-angled instrumentation.

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The surgeon has the option of treating the fracture through the intraoral approach under direct vision or may opt for endoscopic assistance. The incision is very similar to the standard incision used to approach the ramus and condyle unit. Surgeon preference for a smaller incision is acceptable. A specific instrumentation is recommended in order to facilitate the endoscopically assisted condylar fracture treatment. Create the optical cavity for the endoscope by elevating the periosteum of the ascending ramus towards the condylar region. Stop the dissection once you have reached the fracture line. Dissection beyond the fracture line will be completed after introduction of the endoscope.

Insertion of the Optical Retractor After assembly of the optical retractor to its handle, insert and place it around the posterior border of the ramus.

Insertion of the Endoscope Insert the endoscope through the optical retractor up to the fracture line.

Dissect over the Condylar Fragment Using the periosteal elevator dissect under endoscopic visualization over the condylar fragment. Care should be taken near the inferior border of the capsule so as not to violate the joint space. If the condylar fracture fragment is initially medially displaced, the surgeon must bring the fragment into a lateral position in order to complete the dissection for the osteosynthesis. This may be a highly demanding procedure.

Fig. 11.10

Wound closure Closure of the intraoral incision After thoroughly irrigating the wound and checking for hemostasis the incision is closed using interrupted or running resorbable sutures.

Surgical Approaches / 97

Surgical dressing An elastic pressure dressing covering the ramus/condylar process region helps support the soft tissues and prevent hematoma formation.

The Use of Existing Lacerations Frequently, patients with facial fractures also have lacerations. Very often, these existing soft-tissue injuries can be used to directly access the facial bones for management of the fractures. The surgeon may elect to extend the laceration to provide adequate access to the fractured area, following the relaxed natural skin creases. Bacterial contamination is not a contraindication for the use of existing lacerations for surgical approach. Wound closure Wound closure for this incision is primary closure of the laceration. Proper cleansing, debridement, and hemostasis should be accomplished prior to closure. The laceration is closed in layers with resorbable interrupted sutures, realigning the anatomic structures and eliminating dead space:  Periosteum  Mimic muscles  Platysma/SMAS  Subcutaneous tissues  Damaged facial and trigeminal nerve branches injured Stensen’s duct are repaired as meticulously as possible. A drain may be used if necessary. SUMMARY

 Vestibular incision is best for simple fracture(symphysis, angle, body) – Preserve mental nerve – Close wound in two layers muscle and mucosa  Extraoral incision for – Complex, difficult, grossly displaced fracture – Preserve the facial nerve – Close the wound in layers – Try to give good scar  Mandibular condyle repair can be done endoscopically.

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12

Fracture of Mandible in Children

Fracture of mandible is not very common in children this is because the bones are resilient at this age and considerable forces are required to cause a fracture. In children the line of demarcation between medulla and cortex is not well defined as in adult. There are more chances of green-stick fractures occurring in children. There is greater risk of damage to the developing teeth than the later years. The treatment of mandible fracture in children before puberty are of conservative management. This is because of rapid healing of bones and adaptive potential of bone and its contain dentition. Some special factors need to be considered during the management of fractured mandible in children.

Hindrance in Growth Potential Children have tooth germs and unerupted permanent teeths. If these are disturbed the normal growth of mandible is disturbed. Development of alveolus will be affeceted in those areas. This damage in a growth potential will be more severe in case of infection in a fracture side. The growth in sub condylar regions can be seriously compromised if there is high condylar fracture leading to restriction of function as a result of fibrous or bony ankylosis of the temporomandiular joint.

Fixation in the Deciduous and Mixed Dentition Period In case of severe displaced fracture which requires immobilization of mandible. Some modification of technique are required because of presence of uninterrupted and partially erupted teeth of permanent dentition and deciduous teeth variable mobility.

Fixation Independent of Teeth a. In very young with unerupted or very few deciduous teeth gunning type splint of lower jaw can be used which can be constructed by trough lined with black gutta percha and retained by two circumferential wires.

Fracture of Mandible in Children / 99

b. When some occlusions are present with caries and loose deciduous tooth in mandible can be suspended on each side with circumferential wires on each side linked to circumzygomatic wires from above. c. A simple elasticated bandage chin support can be given in case of minimally displaced fractures where jaw movements are not that painful.

Fixation Utilizing the Teeth Patient with erupted deciduous and permanent teeth:  Simple arch bar and eyelet wiring can be done. This arch bar is to be fixed to the teeth with more thinner, flexible, soft Stainless steel of 0.35 mm diameter.  Light arch bar of german silver can be used for irregular dentition as they are more easily adaptable. This should be attached to the tooth by similar 0.35 mm diameter wire.  Orthodontic brackets can be bonded directly on a tooth in case of simple fracture.

Unerupted Tooth Patient below age of 9–10 years the body of mandible is conjusted with developing teeths so its unsafe to apply transosseous wires or to insert bone pains or plate in them. In cases of gross displacement of fractures the lower border should be wired with caution. The bones pins and plates are contraindicated.

Follow-up The healing in children is very rapid. Some fractures are stable within a week and get firmly united in three weeks time. Fracture did not need to be reduced perfectly. Imperfection in reduction can be accepted rather than refracturing the mandible with possible damage to the developing teeth. In case of above circumstances continuing growth and eruption of teeth will compensate for the imperfect alignment of fragment. A prolonged follow-up is required in order to be sure that there is no longterm effect on both mandibular growth and normal development of permanent dentition. Close cooperation with paedodontist, orthodontist and dentist is of vital importance. SUMMARY

 Growth of the bones are rapid.  Interference with growth potential should be kept in mind.  Conservative management to be done for fracture mandible in children.  Perfect reduction not required.  Prolonged follow-up is required.

100 / Fracture Mandible

13

Postoperative Care

The postoperative care is also very important as the intraoperative care. With the advent of this direct osteosynthesis technique postoperative care has simpler and safer. The postoperative care is divided into three phases: 1. Immediate postoperative phase—this is the phase when is recovering from the general anesthesia. 2. Intermediate phase—this is a phase before the clinical bony unions has been established. 3. The late postoperative phase—this includes removal of fixation biterehabilitation, physiotherapy and long-term observation of dentition.

Immediate Postoperative Phase This is a phase in which we are highly dependent on intensive care unit staff. In case of absence of such facilities an experienced nurse should remain with the patient till the recovery is complete. An intermaxillary fixation is carried out instruments like cutters, screw drivers and scissor should be easily available near the bed side so that in a case of emergency this fixation can be removed immediately. Patient should be return from the theatre with nasopharyngeal airway in position and this should be left in situ until the patient recovers unconsciousness. In case of patient being unconscious or a patient sedated postoperatively or associated extensive soft tissue injury to the oropharynx. A tongue suture should be taken which should pass transversely across the dorsum of the tongue as an additional safeguard. A suction machine should be kept beside patient to suck any saliva or oozing blood from the mouth. In case of vomiting with patients consciousness down there may be chances of aspiration. In such cases immediately the intermaxillary fixation should be removed and accordingly patient need to be intubated.

Postoperative Care / 101

Intermediate Postoperative Phase General Supervision Once a patient gains consciousness tongue suture if taken should be removed. Patients occlusion need to be checked as early as possible. Any unacceptable reduction need to be corrected in an early stage. Intermaxillary fixation should be inspected for its loosening of wire or removal of wire. A postoperative edema should be kept in a mind and should be informed to the patient and the relatives about it before the operation. Any increase in a swelling with sign of infection require immediate attention.

Prevention of Infection Cases of fractures of tooth bearing areas injection augmentin + injection mertrogyl should be given for 5 days. If healing goes well antibiotic can be discontinued after 5 days. Simple closed fractures of condyle neck do not require any prophylactic antibiotic.

Oral Hygiene This play an important role in the prevention of infection in a fracture line. Hot normal saline mouth washes are given after every meal for conscious patients in a case of immobilization by any of wiring techniques. Patient is asked to do a toothbrush in a visual manner. The size of the tooth brush should be of a smaller size. Betadin gargle or 0.2% chlorhexidine gluconate mouth wash significantly reduce the bacterial count and improves a plaque control in patient with intermaxillary fixation. Patient who does not cooperate, mouth must be cleaned by a nursing staff after every meal using normal saline solution with the help of hugginson and syringe. Care must be taken not to direct the stream of fluid down the side of nay compounded fractures, so introducing infection. Caps splints can be cleaned with 1–4% sodium bicarbonate solution. Rubber band if soiled with food should be changed. The lip should be kept lubricated with petroleum jelly to prevent drying and sticking of the lips. If the lips are excoriated and sore 1% hydrocotisone ointment can be applied.

Feeding The problem of providing a patient suffering from maxofacial injury with adequate nutrition varies according to whether the patient is conscious and cooperative or is uncooperative.

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Conscious Cooperative Patient Depending upon a size of the gap between the fixation of the patients can have a semi solid or a liquid diet. A diet of 2000–2500 calories is adequate for most patients nutritional requirement. Liquid or a semi solid diet should be given in consultation with dietitian. Milk and milk products are encouraged for regular daily consumptions. Diet should be supplemented with vitamins iron preparation and high calorie protein preparation such as complain. Use of flavouring agents should be used and liking of patients should be considered to maintain the patients interest in a diet. A big diameter straw can be used for sucking liquids.

Unconscious and Uncooperative Patient Patients fluid and electrolyte should be maintained. A help of a physician, surgeon, and dietitian is required to maintain the nutrition and metabolism of patients. Rhyles tube should be inserted to feed the patient and if Rhyles tube feeding is not adequate parental fluid therapy should be started with consultation of the physician.

Late Postoperative Care Removal of Fixation The intermaxillary fixation in terms of wire technique can be removed after the period of immobilization of the specific area fracture. Wire ligatures and eyelets should be unwound a few turn to loosen them and the wire cuts in such a way that there are no residual obstruction in smooth withdrawal of the wire. Nevertheless the process is uncomfortable for the patient. After removal, the mouth should be cleaned with antiseptic solutions, antibiotic is given for 3–5 days as a prophylaxis to the infection with betadin or 1% chlorhexidine solution for a mouth wash. In a cases of rigid osteosynthesis as it produce stable union not much care is required. Patient should be kept on a soft diet for first two weeks and carefully monitored for any wound infection. There is no need to remove this fixation unless there is an infection or an exposure in the mouth or extrusion from the skin.

Adjustment of Occlusion Little adjustment of occlusion is required if wiring technique is employed as the cusps are placed in a correct position under a direct vision at the time of immobilization. In case of caps splint, however, accurate the splint may be

Postoperative Care / 103

a slight adjustment of occlusion is always required. Slight dearrangement of occlusion can often be overcome by allowing the patient to masticate normally as there is sufficient elasticity in recently healed fracture to allow occlusion to correct itself. Patient with fracture of edentulous mandible can seldom wear their original lower dentures and a new one is required when a fracture is healing.

Mobilization of Temporomandibular Joint After removal of wires there may be a slight pain in the temporomandibular joint in initial period. Patient need to be encouraged for the movement of temporomandibular joint. Patient is asked to open and close mouth frequently to break the muscles spasm initially, after that there should be no difficulty in moving their temporomandibular joint. SUMMARY

 Patients nutrition should be maintained.  Oral hygiene should be taken special care.  In compound fractures infection should be prevented.  Wire cutters, suction machine should be kept at the bed side.  A dental reference to be done after removal of wires done for the wiring technique.  Implants need not require to be removed unless and until it is exposed, infected or extruded.

104 / Fracture Mandible

14

Complications

Serious complication arising as a result of fracture mandible are rare as fractures are treated competently nowadays. Minor complication are commoner than the major one. The complications are divided into early complication and late complication.

Early Complication Hemorrhage There can be hemorrhage in a soft tissue which may require drainage if its localized. Some symphysis and parasymphysis fractures can be accompanied with tear in a soft tissue which extends along the floor of mouth as far as pharynx. This tear opens the deep spaces of a neck to blood and saliva thus permitting infecting to the deep spaces of neck which can track into the thorax. If such tears are present tissue in a floor of mouth should be closed in layer with drain in a dependant portion of the wound with antibiotic coverage.

Carotid Injury Severe mandibular dislocations may damage the carotid artery, resulting in aneurysm formation or thrombosis with stroke. The condyle is frequently driven into the auricular canal, because it is adjacent to it, lacerating the canal and resulting in bleeding.

Facial Nerve Injury Contusion and laceration of facial nerve can occur leading to palsy or paralysis.

Infection By achieving adequate stability of bone fragment in a fracture area reduce the possibility of infection. More chances of infection in cases of periosteal stripping which decreases the blood supply.

Complications / 105

Infected fractures will usually demonstrate one or more of the following signs/symptoms:  Swelling  Erythema  Trismus  Pain  Purulent discharge. Infection occurring in fractures usually results from one or more of the following etiology:  Microorganisms  Fracture instability  Devital tissues (teeth, bone, etc). The treatment of infected fractures involves:  Incision and drainage of abscesses,  Irrigations of the wounds as necessary  Systemic antibiotics  Removal of devital teeth/bone  Removal of any loose internal fixation devices  Restabilization of fracture  Stronger and longer plates need to be applied  Function should be permitted after the infection is cleared  Bone grafting should be considered in a case of big gap in a fracture.

Avascular Necrosis, Osteitis, and Osteomyelitis This is more common in a older patient with edentulous mandible, in old patient the inferior alveolar artery and vein get smaller in size thus decrease blood supply to the mandible leading to potential of avascular necrosis. This can be further increased by periosteal stripping.

Treatment a. Early reduction of fracture with immobilization b. Drainage of absess if any otherwise osteitis can progress into osteomyelitis True osteomyelitis in mandible is relatively uncommon. Localized osteitis occur but this condition rarely progress into true osteomyelitis. The use of antibiotic, the prompt drainage of area prevent this occurance of osteomyelitis. If osteomyelitis occurs it should be easily demonstrated radiographically as increased fluffiness and varying opacity of the bone.

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Treatment a. b. c. d. e.

All sequestra and devitalized bone should be removed Any internal fixation should be removed Higher antibiotic should be started Appropriate drainage if required should be done Bone should be stabilized with external fixation

Late Complication Nonunion A nonunion occurs when the mandible does not heal in an appropriate time frame. Healing at the side of mandible fracture is completed within 4–8 weeks. Remodelling and bone healing continue histologically for 26 weeks. The result is mobility of the fracture segments present after an adequate healing phase. Patients may also demonstrate malocclusion and infection at the site of fracture.

Etiology Nonunions are usually the result of one or more of the following factors: a. Fracture instability (mobility) b. Infection c. Inaccurate reduction d. No contact between fragments e. Decrease blood supply to the bone f. Poor nutritional condition of the patient g. Old edentulous patient h. Lack of water tight intraoral closure, bathes the fracture in bacteria thus leading to nonunion

Treatment Treatment will consist of:  Identifying the cause  Controlling infection  Surgical reconstruction: Removing the existing hardware, debridement of devital bone and/or soft tissues, decortication of bone fragments at the fracture ends, re-establishing occlusion, stabilizing segments using a locking reconstruction plate 2.4, and autogenous bone graft to this area.

Complications / 107

Malunion/Malocclusion Etiology Malunions occur for at least one of several reasons:  Inadequate occlusal reduction during surgery  Inadequate osseous reduction during surgery  No osseous reduction (e.g. condyle fractures)  Imprecise application of internal fixation devices  Inadequate stability (lack of rigidity)

Treatment The treatment of a malunion must involve:  Identification of the cause  Orthodontic/orthopedic treatment if possible  Osteotomies as necessary (refracture, standard osteotomies, combinations)

Ankylosis Ankylosis is a process where the mandibular condyle fuses to the glenoid fossa. This generally occurs after prolonged immobilization (MMF) of a condylar fracture. Patient demonstrating their maximum interincisal opening after treatment of multiple mandibular fractures and prolonged period of MMF. The treatment of ankylosis in this case is additional surgery in the form of a gap arthroplasty or total alloplastic joint replacement.

Fixation Failure Implant failure includes plate fracture and screw head fracture. Fixation failure results in fracture mobility that can subsequently lead to infection, nonunion and/or malunion. Fixation fails by a number of mechanisms which include:  Insufficient amount of fixation  Fracture of the plate  Loosening of the screws  Devitalization of bone around screws

Insufficient Amount of Fixation Left mandibular angle fracture was treated using a malleable miniplate 2.0 at the inferior border of the mandible. This is insufficient fixation for this fracture.

108 / Fracture Mandible

Illustration demonstrating biomechanics of an angle fracture. A small plate applied at the inferior border provides insufficient stability in such a fracture. It cannot prevent a gap from opening at the superior surface of the mandible under function.

Limitation of Opening of Mouth Fig. 14.1: Complication after Prolong immobilization of mandible and insufficient amount of fixation intermaxillary fixation can result in weakening of muscle mastication. With substantial hemorrhage within muscle can occur leading to organized hemotoma with early scar tissue formation. All this leads to decrease mouth opening.

Treatment a. Physiotheraphy may accelerate the recovery period b. Simple jaw excercise should be employed c. Occasionally manipulation of mandible under anesthesia may assist the breakdown of scar tissue within muscle.

Fibrodysplasia Ossifficans This involve the main muscle of mastication and it is a very rare combination of fracture mandible. The hematoma which occurs in muscle get organized and eventually become ossified, this view is supported by finding of trabecular bone within the muscle mass.

Treatment a. Excision of ectopic bone b. There is a high chance of recurrence.

Scar Etiology a. b. c. d.

Contamination of wound with dirt specially tar products Improper technique of suturing Associated infection Tendency of patient

Complications / 109

Treatment a. b. c. d. e. f.

Wait and watch for 1st year as they may soften and fed away Massage of the scar Pressure bandage Application of lanoline Infilteration of injection kenacort and hylinese Surgical revision if possible SUMMARY

 Proper reduction, stable and appropriate fixation with prevention of infection can prevent most of the complication of fracture mandible.  In cases of edentulous patient, grossly contaminated fractures, poor nutritional condition of the patient, complication like malunion, nonunion should be kept in mind.  All devitalized structures, infected tissue, loose plates and srews should be removed and replaced by appropriate ones.

Index / 111

Index Page numbers followed by f refer to figure

A Accessory muscles of mastication 16 Acrylic splints 47 Airway maintenance 39 Alkayat-Bramley preauricular incision 90 Angle of mandible 13 Ankylosis 107 Anterosuperior alveolar nerve block 66 AO classification of mandibular fractures 24 Arch bars 44 Avascular necrosis 105

B Basal triangle fracture of parasymphysis area 78f Bilateral condylar fractures 32 Biomechanics of mandible 10, 11f Blood loss 39 vessels 17 Blunt dissection of parotid gland 87 Bonded modified orthodontic brackets 47 Buccal nerve block 71 Buccinator muscle 93, 95

C Carotid injury 104 Categories of associated fractures 25 fractures 25 occlusion 25 soft tissue involvement 25 Champy’s line 74f of osteosynthesis 74 Closed reduction 74 Combination with transbuccal technique 94 Comminuted fracture 22, 22f, 33, 52 of angle and body 78f of parasymphysis 77f Complex symphysis 77 Complication after insufficient amount of fixation 108f

Compound fracture 22, 22f Compression plating 49 technique 50 Computed tomographic scan 37 Condylar fractures 32 Conscious cooperative patient 102 Contact healing 9 Control of infection 41 Conventional plate system 58, 59 screws 57 Countersink near cortex 54

D Dental terminology 4f Dentoalveolar fractures 31 Determine screw length 53, 53f Different levels of force distribution 60 Dissect over condylar fragment 96 Dissection 84, 87, 88 of joint capsule 89 Dynamic compression plate 48, 50f

E Eccentric drilling for compression 50 Eyelet method 46 of fixation 46f

F Face lift incision 88, 89f Facial nerve injury 104 Factors affecting bone healing 10 Feeding 101 Fibrodysplasia ossifficans 108 Fixation failure 107 in deciduous and mixed dentition period 98 independent of teeth 98 utilizing teeth 99

112 / Fracture Mandible Fracture 18 angle of mandible 26 condyle 26 displacement 26 in canine region 26 of angle 33 and ramus 77 of body 34 of mandible 26 of coronoid process 27, 33, 81 of head of condyle 79, 80 of mandible 20 of ramus 33 of mandible 27 of symphysis 27 and parasymphysis 34 site exposure 92 Frequency of fracture 19

G Gap healing 9 Gilmer method 46 of fixation 46f Grades of severity 25 Greater palatine block 69 nerve block 68 Greenstick fracture 22, 22f

Insertion of endoscope 96 optical retractor 96 Insufficient amount of fixation 107 Intermaxillary fixation 44 screw technique 47, 47f Intermediate load-sharing situation 61 Intraoral incison for symphysis and body fracture 91f

L Lag screw 51 principle 51f and technique 51 technique 51, 52 Limitation of opening of mouth 108 Load-bearing osteosynthesis 59, 61f, 78f Load-sharing osteosynthesis 59, 78f Local anesthesia 64 examination of mandibular fracture 29 Location of mental foramen 72 Locking head screws 57 plate 54 system 58, 59 reconstruction plate 55, 56f Lower jaw infiltration 70

H Head entering medullary space 54f Healing of fracture 7f, 8f bone 9 Hemorrhage 104 Hindrance in growth potential 98 Horizontally favorable fractures 23, 23f unfavorable fractures 23, 23f

I Ideal lines of osteosynthesis 60 load-sharing situation 61 Incising temporalis fascia 89 Inferior alveolar nerve block 70 Infra-alveolar nerve block 70 Infraorbital block 68 nerve block 66, 68

M Malreduction of fracture 60f Mandibular condyle fracture 79 muscles 14 Mental nerve block 72 Mentalis muscle dissection 92 Middle superior alveolar nerve block 66, 67 Minihole plate 75f Miniplate at external oblique line 78f osteosynthesis 74 Mobilization of temporomandibular joint 103 Mucosal incision 91 for angle fracture 92f for condyle and ramus fracture 94f Multiple and comminuted fractures 34

Index / 113 Muscles of facial expression 14 mastication 14

N Neck of condyle 13 Nerves 16 Neurovascular structures 85, 88, 91 Nonrigid osteosynthesis 48

O Off-angle drilling 51f Open reduction 81 Option for off-angle drilling 51 Osteitis 105 Osteomyelitis 105

P Parasymphysis fracture 76, 77 Pathological fractures 18 Period of mobilization 43 Phases of fracture healing 6 Posterosuperior alveolar nerve block 65, 66 Prevention of infection 101 Primary bone healing 9 loss of reduction 58

R Removal of fixation 102 Rigid osteosynthesis 48 Rowe modification 90

S Screw driver and screw 75f insertion 53f, 54 Secondary loss of reduction 59 Semirigid osteosynthesis 48 Sensory buccal nerve 93, 95 Sign and symptoms of mandibular fractures 31 Simple fracture 21, 21f Single fracture 33 Skin incision 85, 88

Soft tissue lacerations 40 Subcondylar fractures 79 Submental extension 84 Subperiosteal dissection of mandibular ramus 87, 88 Support of bone fragments 40 Surgical dressing 97 flap dissection 91 Symphysis fracture 76 of mandible 13

T Temporomandibular joint 17 Threaded plate hole and threaded screw head 57f Three-dimensional CT scan 38 Tranparotid approach skin incision 86f Treatment of infected fractures 105 Triangular base fracture at angle of mandible 78f Type of fixation 43f

U Unerupted tooth 99 Unilateral condylar fractures 32 Universal fracture plate 59 Use of existing lacerations 97

V Variations in incision 83f Various site of fracture 20f submandibular incisions 84f Vascular supply of mandible 16 Vertically favorable fractures 23, 23f unfavorable fracture 24, 24f Vestibular incision 91-93

W Wiring techniques 46 Wound closure 84, 88, 89, 92, 96, 97 of vestibular incision 94 using envelope flap 94