Fractures of the Mandible

Question 1

Fractures of the mandible alone are seldom life threatening except in the following
instances:

Answer 1

1. Loss of airway. This is usually associated with gross displacement of fragments,
   excessive blood and secretion accumulation in the airway or reduction of the
   level of consciousness, either from head injury or consumption of medically
   administered drugs (e.g. morphine), illicit drugs or recreational drugs (including
   alcohol). Foreign bodies may be aspirated, even into the lung e.g. displaced
   tooth fragments, denture fragments or even bone fragments or missiles (e.g. a
   bullet). An apparent missing tooth is in the airway until proven otherwise.
2. Uncontrollable haemorrhage, from bone or soft tissues.
3. Infection of the fracture, which if extensive or rapidly progressing, may
   compromise the airway, and lead to the general demise of the patient. This
   situation is fairly rare and usually occurs when the individual “presents late”.

Question 2

Important questions to ask during history taking

Answer 2

Of special note are the following:
1. Did the patient lose consciousness (if so the patient should be admitted for 24
hrs. – or longer observation, an intracranial bleed may be in – progress)?
2. When and where did the injury occur?
3. How did the injury occur? Be suspicious if there is a history of severe trauma
(other injuries are usually involved, e.g. other maxillofacial injuries, or general
body injury).
4. The use of any medication / toxin especially at the time of injury.
5. Other problems which might cause a “faint and fall” e.g. uncontrolled epilepsy,
significant anaemia and poorly controlled diabetes.

Question 3

Usual radiographic views include:

Answer 3

1. Panoramic dental radiograph – remember that this is a two dimensional view and
   mistakes can be made when using it alone e.g. missing a relatively undisplaced
   condylar fracture.
2. Posterior – anterior view of the skull – in particular this provides information
   about the status of the condylar necks and angle of mandible
3. Reverse Towne’s view – This is very useful for detection of condylar neck
   fracture.
4. If a panoramic machine is not available, one may have to rely on left and right
   lateral oblique radiographs – interpretation takes some practice.
5. Mandibular anterior occlusal plane view – when fractures surrounding, or at, the
   mandibular symphysis are suspected.
6. Cone – beam scanning – especially useful for visualisation of fractured and
   displaced condyles.
7. Technetium 99 bone scan – Not really in the realm of the general dentist, but
   helps in the diagnosis of various pathologies.

Question 4

Fractures of the mandible alone are seldom life threatening except in the following
instances:

Answer 4

1. Loss of airway. This is usually associated with gross displacement of fragments,
   excessive blood and secretion accumulation in the airway or reduction of the
   level of consciousness, either from head injury or consumption of medically
   administered drugs (e.g. morphine), illicit drugs or recreational drugs (including
   alcohol). Foreign bodies may be aspirated, even into the lung e.g. displaced
   tooth fragments, denture fragments or even bone fragments or missiles (e.g. a
   bullet). An apparent missing tooth is in the airway until proven otherwise.
2. Uncontrollable haemorrhage, from bone or soft tissues.
3. Infection of the fracture, which if extensive or rapidly progressing, may
   compromise the airway, and lead to the general demise of the patient. This
   situation is fairly rare and usually occurs when the individual “presents late”.

Question 6

COMPOUND fracture

Answer 6

the fracture communicates with the intra – oral or extra – oral
environment. Most mandibular fractures communicate with the intraoral
environment, through the torn periodontal ligament. Infection of the fracture line
occurs readily in the latter case.

Question 7

GREENSTICK fracture

Answer 7

only one cortical plate is fractured, while the other bends. This
fracture tends to occur particularly in children, who have very elastic bone.

Question 8

COMMINUTED fracture

Answer 8

a fracture which frequently challenges the surgeon in
management. There are multiple fracture lines in the same area. These are
usually associated with severe impact to the mandible, e.g. gunshot injury, a
blow with a hammer to the tissues overlying the bone.

Question 9

History taking after trauma

Answer 9

1. Did the patient lose consciousness (if so the patient should be admitted for 24
   hrs. – or longer observation, an intracranial bleed may be in – progress)?
2. When and where did the injury occur?
3. How did the injury occur? Be suspicious if there is a history of severe trauma
   (other injuries are usually involved, e.g. other maxillofacial injuries, or general
   body injury).
4. The use of any medication / toxin especially at the time of injury.
5. Other problems which might cause a “faint and fall” e.g. uncontrolled epilepsy,
   significant anaemia and poorly controlled diabetes.

Question 10

Intraoral examination – points to be noted

Answer 10

1. The “trauma patient” may be non – compliant and may limit your examination.
   Try to look for a malocclusion or steps in the dentition.
2. In a compliant patient with limited trismus, you may be able to elicit mobility
   across the segments.
3. Look for a haematoma, especially if it is in the soft tissues lingual to the
   mandibular symphysis (usually a sign of symphyseal or parasymphyseal tearing
   of periosteum related to a mandibular fracture).
4. Note missing or mobile teeth. (An occasional patient main complaint is that he /
   she has a mobile tooth e.g. third molar – look for an underlying fracture at the
   angle)
5. Check the maxilla for mobile, missing or displaced teeth. Check for maxillary
   mobility, by grasping each side with your fingers and holding the glabella with the
   fingers.
6. Note any soft tissue lacerations, especially to the tongue (which may result in
   severe swelling later – may occlude the airway). In an unconscious or semi –
   conscious patient the tongue may have lost its anterolingual attachments and fall
   back into the airway. This may also occur in double fractures of the
   parasymphyseal region.

Question 11

Radiographs for mandibular fractures

Answer 11

1. Panoramic dental radiograph – remember that this is a two dimensional view and
   mistakes can be made when using it alone e.g. missing a relatively undisplaced
   condylar fracture.
2. Posterior – anterior view of the skull – in particular this provides information
   about the status of the condylar necks and angle of mandible
3. Reverse Towne’s view – This is very useful for detection of condylar neck
   fracture.
4. If a panoramic machine is not available, one may have to rely on left and right
   lateral oblique radiographs – interpretation takes some practice.
5. Mandibular anterior occlusal plane view – when fractures surrounding, or at, the
   mandibular symphysis are suspected.
6. Cone – beam scanning – especially useful for visualisation of fractured and
   displaced condyles.
7. Technetium 99 bone scan – Not really in the realm of the general dentist, but
   helps in the diagnosis of various pathologies.

Question 12

Simple mandibular fracture

Answer 12

SIMPLE – a single fracture line through the involved bone. In the case of the
mandible the radiographically detected fracture lines will merge at the lower and
upper border of the mandible.

Question 14

Compound mandibular fracture

Answer 14

COMPOUND – the fracture communicates with the intra – oral or extra – oral
environment. Most mandibular fractures communicate with the intraoral
environment, through the torn periodontal ligament. Infection of the fracture line
occurs readily in the latter case.

Question 15

GREENSTICK fracture

Answer 15

GREENSTICK – only one cortical plate is fractured, while the other bends. This
fracture tends to occur particularly in children, who have very elastic bone.

Question 16

COMMINUTED fracture

Answer 16

COMMINUTED – a fracture which frequently challenges the surgeon in
management. There are multiple fracture lines in the same area. These are
usually associated with severe impact to the mandible, e.g. gunshot injury, a
blow with a hammer to the tissues overlying the bone.

Question 17

CONDYLAR HEAD FRACTURE

Answer 17

CONDYLAR HEAD FRACTURE - may be extra – capsular or intra – capsular.
These fractures, unless managed correctly may result in ankylosis of the
temporomandibular joint.

Question 18

CONDYLAR NECK FRACTURE

Answer 18

CONDYLAR NECK FRACTURE – more commonly encountered and has some
chance of causing ankyloses if not managed correctly.

Question 19

RAMUS FRACTURE

Answer 19

RAMUS FRACTURE – usually not of great significance – splinted by muscle
attachments.

Question 20

Coronoid Process Fracure

Answer 20

CORONOID PROCESS FRACTURE – usually not of great significance, but as
with the ramus fracture, may cause trismus (limitation of opening ascribed to
pain and muscle spasm).

Question 21

ANGLE FRACTURE

Answer 21

ANGLE FRACTURE – occurring in a week area associated with the position of
the third molar and spreading down to the area of the lower border, where
masseter and medial pterygoid attach.

Question 22

Body Fracture

Answer 22

BODY FRACTURE – occurs between angle and parasymphysis

Question 23

Parasympheal Fracture

Answer 23

PARASYMPHYSEAL FRACTURE – between the canines

Question 24

Symphyseal Fracture

Answer 24

SYMPHYSEAL FRACTURE – occurring in the mandibular midline

Question 25

Dentoalveolar Fracture

Answer 25

DENTO – ALVEOLAR FRACTURE – involving teeth and alveolar bone.

Question 26

five basic principles of bone fracture treatment:

Answer 26

1. Reduction 2. Alignment 3. Immobilization 4. Prevention of infection 5. Restore function and aesrthetics

Question 27

Reduction

Answer 27

REDUCTION: This is the active movement of displaced fragments towards each other, which the clinician attempts to achieve.

Question 28

Alignment

Answer 28

ALIGNMENT: This is the exact approximation of the bone ends into their pre – fracture relationship.

Question 29

Immobilization

Answer 29

IMMOBILISATION: This term is used to describe the FIXATION of the bone ends together (as rigidly as possible) in order to allow bone healing without relapse.

Question 30

Prevention of infection

Answer 30

PREVENTION OF INFECTION: This phase is a challenge, especially when the patient presents “late”. If the fracture is compound, a five day antibiotic course is usually used. The better the fixation and general good surrounding soft tissue management generally lowers the chance of infection significantly.

Question 31

Presence of teeth in the fracture line

Answer 31

As a general rule, if left these are a major cause of infection! If one wishes to retain these (e.g. a lower incisor) the following principles are of importance: a. If the apex of the tooth is involved, root canal therapy should be performed. Other teeth in the region should be followed up for the development of complications such as later loss of vitality. b. If a tooth is mobile or periodontally involved, it is best removed. c. If there is major damage to the tooth, it may have root fractures and is best removed. Should the periodontal ligament be avulsed from the tooth, it requires removal.

Question 32

There are two basic methods of reducing, aligning and fixation of the mandible.

Answer 32

Closed reduction fractured mandible (CRFM) Open reduction fractured mandible with internal fixation (ORIF)

Question 33

Closed reduction fractured mandible (CRFM):

Answer 33

The fracture/s are not exposed surgically. Usually intermaxillary fixation (IMF) is used, by the means of wires or arch bars. The “favourability” of the fracture usually impacts on this method of treatment and infected fractures often don’t respond well to this type of treatment.

Question 34

Open reduction fractured mandible with internal fixation (ORIF):

Answer 34

Occlusion is usually maintained by IMF and the fracture sites exposed. Accurate reduction of the entire bony fracture (e.g. displaced lower border) is generally achievable. Fixation is achieved by the placement of miniplates or occasionally wire sutures or other methods. This represents semi-rigid fixation and usually the patient is usually kept in some form of fixation for a varying period. In a compliant patient (if he / she takes a very soft diet) this fixation may only be only used for about a week and the patient followed-up carefully for the development of malocclusion, in which case the fixation is usually replaced for a while. In the case of condylar fractures, as a very general rule elastic IMF is frequently utilised, to allow a little movement. This is thought to assist in the prevention of ankyloses (bony or fibrous fusion of the temporomandibular joint)

Question 35

Gunshot injuries to the mandible

Answer 35

Unfortunately these are becoming more and more common in South Africa. They are usually grossly comminuted. There are two different approaches to initial management: 1. Closed reduction (CRFM) in order not to strip periosteal blood supply from small fragments. 2. Open reduction (ORIF) using a reconstruction plate.

Question 36

THE CONCEPT OF FAVOURABILITY AND UNFAVOURABILITY OF MANDIBULAR FRACTURES

Answer 36

Two evaluations are made: 1. Horizontally favourable (not that common)-The mandible is viewed from the horizontal angle i.e. from the lateral surface (usually on panoramic radiograph or lateral oblique view) 2. Vertically favourable (an attempt is made to view the fracture from a “vertical” aspect i.e. from the alveolar area to lower border of mandible). This means that a posterior – anterior view is useful.

Question 37

METHODS OF INTERMAXILLARY FIXATION FREQUENTLY USED

Answer 37

1. Eyelet wires: These are placed around the teeth as per the diagram below. The round loop is the “eye” and the intermaxillary wires are passed through these eyes. 2. Arch bars: The type usually used is the Erich bar. This is wired to the teeth with single loops of wire. The bar has lugs and these can be used to fix the jaws together with wires or elastic loops. Utilising elastic loops provides greater ease of removal and increased safety post – operatively. 3. “IMF” screws. These are little fixtures which are screwed into bone below the dentition. They are of assistance in supplementing IMF or used alone in less challenging cases.

Question 38

List the COMPLICATIONS OF MANDIBULAR FRACTURES

Answer 38

* Infection * Non-union * Fibrous union * Delayed union * Malunion * Ankylosis of the temporomandibular joint * Neural damage

Question 39

Infection as a complication of mandibular fractures

Answer 39

Infection: May involve bone or surrounding soft tissues. Common causes are teeth left in the fracture line, infected small devitalised fragments of bone (sequestra), loose hardware (bone plates and screws), fracture mobility.

Question 40

Non-union

Answer 40

Non-union: Bony union is heavily dependent on the general health of the patient and also local factors, such as fracture mobility, infection, bone gap etc.

Question 41

Fibrous union

Answer 41

Fibrous union: Fibrous tissue forms across the bone gap instead of bone. Fibrous tissue tends to survive in situations which are not ideal. Occasionally this type of union is acceptable.

Question 42

Delayed union

Answer 42

Delayed union: Some significant mobility (slight mobility can be ignored – usually firms with function) across the fracture site – increased fixation time may be necessary.

Question 43

Malunion

Answer 43

This is a serious problem and usually occurs in two instances, patient not seeking treatment within a reasonable time, a bad surgical outcome (any surgery is not an exact science). Usually post – traumatic osteotomy, with internal fixation is used to correct the mal – alignment.

Question 44

Neural damage:

Answer 44

This may be present as the result of fracture occurring along the course of the mandibular nerve (inferior alveolar) in bone (and this condition should be recorded in the notes) or the result of operator trauma, especially when debriding fractures presenting late for surgery.