Fracture Mandible, 1E (2012)

F

RACTURE

Rajesh R Yadav MS (ENT) DORL FCPS

Rajawadi Hospital

Formerly Registrar

Shri Harilal Bhagwati Hospital Mumbai, Maharashtra, India

Akancha R Yadav BDS

Prakash V Dhond MS (ENT) DORL

Mumbai, Maharashtra, India

Foreword

Chris De Souza

F

RACTURE

M

ANDIBLE

JAYPEE BROTHERS MEDICAL PUBLISHERS (P) LTD

New Delhi • Panama City • London

Website: www.jaypeebrothers.com Website: www.jaypeedigital.com

© 2012, Jaypee Brothers Medical Publishers

All rights reserved. No part of this book may be reproduced in any form or by any means without the prior permission of the publisher.

Inquiries for bulk sales may be solicited at: [email protected]

This book has been published in good faith that the contents provided by the authors contained herein are original, and is intended for educational purposes only. While every effort is made to ensure accuracy of information, the publisher and the authors specifically disclaim any damage, liability, or loss incurred, directly or indirectly, from the use or applica-tion of any of the contents of this work. If not specifically stated, all figures and tables are courtesy of the authors. Where appropriate, the readers should consult with a specialist or contact the manufacturer of the drug or device.

Fracture Mandible

First Edition : 2012

ISBN 978-93-5025-801-9

Printed in

Jaypee Brothers Medical Publishers (P) Ltd.

Jaypee Brothers Medical Publishers (P) Ltd 4838/24, Ansari Road, Daryaganj

New Delhi 110 002, India Phone: +91-11-43574357 Fax: +91-11-43574314

Email: [email protected]

J.P. Medical Ltd. 83 Victoria Street London SW1H 0HW (UK) Phone: +44-2031708910 Fax: +02-03-0086180 Email: [email protected] Overseas Offices Headquarter

Jaypee-Highlights Medical Publishers Inc. City of Knowledge, Bld. 237, Clayton Panama City, Panama

Phone: +507-317-0496 Fax: +507-301-0499

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.

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.

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

Dentition

1

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 6 months Lateral incisor 7 months Cuspid 16 months First molar 12 months Second molar 20 months

Human permanent teeth eruption sequence

Maxillary

Central incisor 7–8 years Lateral incisor 8–9 years Cuspid 11–12 years

First premolar 10–11 years Second premolar 10–12 years First molar 6–7 years Second molar 12–13 years

Mandibular

Central incisor 6–7 years Lateral incisor 7–9 years Cuspid 9–0 years First premolar 10–12 years Second premolar 11–12 years First molar 6–7 years Second molar 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

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

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 wear-facets 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

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.

2

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

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

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.

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

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

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

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.

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.

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

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. 3.2B: 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.

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.

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.

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

 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%

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. Classification based on anatomical location of the fractures

A. Fracture of the symphysis B. Fracture of the canine region

C. Fracture of the body of the mandible D. Fracture of the angle of the mandible E. Fracture of the ramus

F. Fracture of the condyle

G. Fracture of the coronoid process H. Fracture of the dentoalveolar

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

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, 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.

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.

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

Fig. 4.6: Greenstick fracture Fig. 4.4: Compound fracture

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.

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.

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. 4.7: Horizontally favorable

fractures

Fig. 4.8: Horizontally

unfavorable fractures

Fig. 4.9: Vertically favorable

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 pos-terior segment can easily get displaced medially without any hindrance.

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. 4.10: Vertically unfavorable

fractures

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

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 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.

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.

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, inter-maxillary 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.

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.

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

 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.

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

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

 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

 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.

 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

 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

 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.

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

 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

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.

6

Radiology

A precise radiological diagnosis is very much important for treatment plan of fracture mandible. It depicts:

a. A exact relationship of teeth in fracture line b. A type of fracture, simple or communited c. Number of fractures

d. Area of fractures

e. 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.

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 posterior-anterior 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

 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. In cases of multiple facial injuries 2. Cases of communated fractures 3. Cases of missile injuries

4. Cases of infected, malunion, nonunion fracture mandible 5. 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.

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.

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