FRACTURES OF THE

MANDIBLE AND
CORONOID PROCESS
Abel
THE MANDIBLE
• THE ONLY MOVABLE CRANIAL BONE.
• TUBULAR LONG BONE, BLUNT
V-SHAPE.
• STRENGTH – DENSE CORTICAL
PLATES
• STRONGEST ANTERIORLY
IN MIDLINE, WITH
PROGRESSIVELY LESS STRENGTH
TOWARDS THE CONDYLES.
• 13 MUSCLE ATTACHMENTS
• JAW CLOSERS: TEMPORALIS, MASSETER, MEDIAL PTERYGOID
• OPENERS: DIGASTRIC, LATERAL PTERYGOID
• GLOTTIC ATTACHMENTS: GENIOGLOSSUS AND GENIOHYOID
• BUCCINATOR, PLATSYMA, MENTALIS, MYLOHYOID, DEPRESSOR LABII
INFERIORIUS, AND DEPRESSOR ANGULI ORIS, CAN INFLUENCE BONE
REMODELING AND DISPLACEMENT IN FRACTURES.
• MAJOR BLOOD SUPPLY TO THE MANDIBLE -> INFERIOR ALVEOLAR
ARTERY, TRANSITIONS TO THE SURROUNDING PERIOSTEUM AND
MUSCLE ATTACHMENT AS THE BODY AGES.

• IN COMMINUTED OR ATROPHIC MANDIBLE FRACTURES, HARDWARE

LOCATION SHOULD TARGET THE HIGHLY VASCULAR AREAS OF THE
MANDIBLE (RAMUS AND SYMPHYSIS) AND AVOID SITES WITH POOR
BLOOD SUPPLY (THE BODY).
• THE INFERIOR ALVEOLAR NERVE INNERVATES ONE HALF OF THE
MANDIBULAR DENTITION AND EXITS AT THE MENTAL FORAMEN TO
SUPPLY THE CHIN AND LIP SOFT TISSUE. THE LINGUAL NERVE RUNS
JUST INFERIOR TO THE ALVEOLUS AND SUPRAPERIOSTEAL IN THE
AREA OF THE THIRD MOLAR IN MOST CASES. EVEN WITH DISPLACED
FRACTURES, THIS NERVE RARELY IS INJURED.
MANDIBULAR
FRACTURES
WHAT IS A FRACTURE?

A LOSS OF BONE INTEGRITY DUE TO MECHANICAL INJURY AND/OR

DIMINISHED BONE STRENGTH.
ETIOLOGY

• MOTOR-VEHICLE RELATED INJURIES

• INTERPERSONAL VIOLENCE
• FALLS
• SPORTS RELATED INJURIES
• PATHOLOGIC FRACTURES
• BALLISTICS
BIOMECHANICAL CONSIDERATIONS
• A mandible fracture has three forces acting on it: compression,
tension, and torsion.
• The muscles responsible for vertical displacement are the masseter,
temporalis, and to a degree the medial pterygoid.
• Horizontal displacement can be caused by the lateral and medial
pterygoid, and torsion by the mylohyoid,
digastrics, and geniohyoid.
Mandibular fracture displacement is defined as:
• Favorable (stable): When the fracture line and the vector of the
muscle pull keep the fracture buttressed and appropriately reduced.
• Unfavorable (unstable): When the fracture line and the vector of the
muscle pull cause displacement.
CLASSIFICATION OF MANDIBULAR
FRACTURES
GENERAL CLASSIFICATION
• SIMPLE/CLOSED
• COMPUND/OPEN
• COMMINUTED
• COMPLICATED/COMPLEX
• IMPACTED
• GREENSTICK
• PATHOLOGICAL
DINGMAN AND NATWIG’S
CLASSIFICATION
KAZANJIAN AND CONVERSE
CLASSIFICATION

• Class I : Teeth on both segments.

• Class II : Teeth on one segment.
• Class III : Edentulous.
ROWE AND KILLEY’S CLASSIFICATION
• Fractures not involving the basal bone.
• Fractures involving the basal bone.
Single unilateral
Double unilateral
Bilateral
Multiple
KRUGER’S CLASSIFICATION
I. Relation to the External Environment
A. Simple or closed
B. Compound or open
II. Type of Fractures
A. Incomplete
B. Greenstick
C. Complete
D. Comminuted.
III. Dentition of the Jaw With Reference to the Use of Splints
A. Sufficiently dentulous jaw
B. Edentulous or insufficiently dentulous jaw
C. Primary and mixed dentition
IV. Localization
A. SYMPHYSIS
B. CANINE
C. BODY
D. ANGLE
E. RAMUS
F. CORONOID
G. CONDYLE
FLOSID CLASSIFICATION
F- FRACTURE TYPE : S-SOFT TISSUE DAMAGE
Incomplete Closed
Simple Open intraorally
Comminuted Open extraorally
Open intra and extraorally
Bone Defect
Soft tissue defect

L-LOCATION OF FRACTURE: I-INFECTION

Left from midline to condylar head Yes
Right from midline to condylar head No

RADIOGRAPHIC ANALYSIS OF INTERFRAGMENTARY

O-OCCLUSION: DISPLACEMENT
Normal Mild
Malocclusion Moderate
Severe
Edentulous
AOCMF – LEVEL 2
•  In the CMF system, fractures of the mandible are identified with the two-digit code
91. In coding the fractures according to their location in the level 2 system, each
fractured region is identified by a letter:
• S = Symphysis/parasymphysis
• B = Body
• A = Angle/ramus
• C = Coronoid process
• P = Condylar process
• The letters specifying the involved regions are added after the initial 91. The regions are
coded in the order from the patient's right side to the patient's left side. In the overall
fracture code, the small letter “m” (abbreviation for “middle”), or the letter “S” if the
symphysis region is fractured, marks the limit between the two sides.
• Letters specified before and after the “m” or “S” refer to the patient's right and left side,
respectively.
• A hyphen sign “-” is inserted in between region letters to indicate that a fracture
extends into an adjoining region (nonconfined). The hyphen is replaced by a point “.”
between two letters to indicate the related regions are involved with separate fractures.
DIAGNOSIS OF MANDIBULAR
FRACTURES

• HISTORY
• CLINICAL EXAMINATION
• RADIOLOGICAL EXAMINATION
HISTORY
• H/O INJURY
• SOURCES OF INFORMATION:
- THE PATIENT
- COMPANIONS AND BYSTANDERS
- AMBULANCE CREW
- THE POLICE
- FIRST AIDERS
ASK ABOUT:
• POSITION OF CASUALTIES
• DEFORMATION OF VEHICLES
• PATIENT’S CONDITION/CLINICAL REPORTS
• PAST MEDICAL HISTORY
• SOCIAL HISTORY
GENERAL EXAMINATION

• FIRST: RECOGNIZE THREATS TO LIFE/LIMB REQUIRING IMMEDIATE

ATTENTION
• SECOND: IDENTIFY ALL CONDITIONS REQUIRING TREATMENTS,
PROVIDING A BASIS FOR TREATMENT PLANNING
• THIRD: IDENTIFY NEW DEVELOPMENTS AND PREVENT
COMPLICATIONS
• First and most critical obligation is to make sure that the airway is
patent and free of potential obstruction.
• The tongue, which may have a tendency to fall back, must be
controlled, and objects obstructing the airway must be removed.
• If an obstruction cannot be removed, a new airway must be
established by endotracheal intubation (remembering possible cervical
spine injuries) or cricothyrotomy.
• After the airway has been secured and respiration is occurring, vital
signs must be assessed, including pulse rate and blood pressure.
• Any significant blood loss is likely to be coming from injuries apart from
those of the face. Other critical injuries must be ruled out, including
intracranial hemorrhages, cervical and other spinal injuries, chest
injuries, abdominal trauma, and fractures of the long bones.
LOCAL EXAMINATION
Local examination of the face and jaws should be conducted in a logical
sequence
The skin of the face and, in particular, the area around the mandible
should be inspected for swelling, hematomas, and lacerations. A
common site for a laceration is under the chin, and this should alert the
clinician to the possibility of an associated subcondylar or symphysis
fracture.
Typically, the patient who has suffered a fracture of the mandibular
condyle will present with facial asymmetry.
This is owing to the loss of the vertical height of the ramus on the side
with the fracture, resulting in a shift of the mandible to the ipsilateral
side.
• Next the dentition is examined for evidence of broken teeth and for
steps or irregularities in the dental arch. The patient is asked to lightly
bite the teeth together and to say whether the bite feels different
from normal.
• Premature occlusal contacts are noted.
• The mandible should then be grasped on each side of any suspected
fracture and gently manipulated to assess mobility.
• The mandible may be compressed by applying pressure over both
angles – look for tenderness.
RADIOGRAPHIC EXAMINATION
• OPG
• LATERAL OBLIQUE
• POSTEROANTERIOR RADIOGRAPH
• OCCLUSAL
• REVERSE TOWNE’S
• CT
INDICATIONS FOR CT
1. Significant displacement or dislocation, particularly if open reduction
is contemplated
2. Limited range of motion with a suspicion of mechanical obstruction
caused by the position of the condylar segment
3. Alteration of the surrounding osseous anatomy by other processes,
such as previous internal derangement or temporomandibular joint
surgery, to the degree that a pretreatment baseline is necessary
4. Inability to position the multiple trauma patient for conventional
radiographs (CT scans may be the only useful radiograph that can be
obtained)
 General principles in the treatment of
mandibular fractures
1. The patient’s general physical status
2. Diagnosis and treatment of mandibular fractures should be approached
methodically not with an “emergency-type” mentality
3. Dental injuries should be evaluated and treated concurrently with treatment
of mandibular fractures
4. Re-establishment of occlusion is the primary goal in the treatment of
mandibular fracture.
5. With multiple facial fracture mandibular fracture should be treated first.
6. Intermaxillary fixation time should vary according to the type, location,
number severity of the mandibular fracture as well as the patient’s age and
health.
7. Prophylactic antibiotics should be used for compound fractures.
Reduction Fixation
Closed Open
- Direct interdental - Transosseous wiring • Direct
wiring/Indirect interdental (osteosynthesis) • Indirect
wiring (eyelet or Ivy loop) - Plating
- Continuous or multiple - Intramedullary pinning
loop wiring - Titanium mesh
- Arch bars - Circumferential straps
- Bone clamps
- Cap splints
- Bone staples
- 'Gunning-type' splints - Bone screws
- Pin fixation
Immobilization
(a) Osteosynthesis without intermaxillary fixation
(i) Non-compression small plates
(ii) Compression plates
(iii) Mini-plates
(iv) Lag screws
(b) Intermaxillary fixation
(i) Bonded brackets
(ii) Dental wiring
-Direct
-Eyelet
(iii) Arch bars
(iv) Cap splints
(v) MMF screws
(c) Intermaxillary fixation with osteosynthesis
(i) Transosseous wiring (ii) Circumferential wiring (iii) External pin fixation
(iv) Bone clamps (v) Transfixation with Kirschner wires
Indications for Open Reduction

• Displaced unfavorable fractures through the angle of the mandible

• Displaced unfavorable fractures of the body or the parasymphyseal

region of the mandible

• Multiple fractures of the facial bones

• Midface fractures and displaced bilateral condylar fractures

• Fractures of an edentulous mandible with severe displacement of the fracture
fragments

• Edentulous maxilla opposing a mandibular fracture

• Delay of treatment and interposition of soft tissue between noncontacting displaced

fracture fragments

• Malunion

• Special Systemic Conditions Contraindicating IMF

Indications for Closed Reduction

• Grossly comminuted fractures

• Edentulous mandibular fractures

• Mandibular fractures in children with developing dentitions

• Coronoid process fractures

• Condyle fractures in certain conditions.

TEETH IN THE LINE OF FRACTURE
• Shetty and Freymiller’s indications for removal of teeth in the line of
fracture:
1. Teeth grossly loosened, showing evidence of periapical pathology or
significant periodontal disease
2. Partially erupted third molars with pericoronitis or associated cyst
3. Teeth that prevent reduction of fractures
4. Teeth with fractured roots
5. Teeth with exposed root apices or entire root surface from the apex
to the gingival margin
6. An excessive delay from the time of fracture to definite treatment
SURGICAL APPROACHES
Intraoral/Transbuccal approach
If the fracture does involve the foramen, care must be taken to avoid
unnecessary nerve injury during mobilization and reduction of the
fracture.
Any granulation, clot, or fibrous soft tissue preventing proper reduction
should be removed.

The fracture sites should be copiously irrigated to dilute microbial

contamination.
Before fixation, all fractures should be accessed and mobilized as
described.
Resuspension of the mentalis muscle should be performed at closure to
prevent a “witch’s chin” deformity. Mucosa can then be closed using a
continuous running 3-0 chromic gut suture
SUBMANDIBULAR APPROACH
SUBMENTAL APPROACH
• The submental approach is used to treat fractures of the anterior
mandibular body and symphysis.
• An advantage to this approach is that the surgeon can easily inspect
the lingual surface of the mandible to assure optimal reduction of the
fracture in this region.
FIXATION ACCORDING
TO FRACTURE SITE
SYMPHYSEAL & PARASYMPHYSEAL
FRACTURES
• PLATE OSTEOSYNTHESIS: Standard technique – two miniplates, 4 or 5-hole,
one placed directly above inferior border, one just underneath tooth roots.
One plate is contoured.
• Monocortical screws for upper plate
• Either mono/bicortical screws for lower plate.
• COMPRESSION PLATE OSTEOSYNTHESIS:
Can be placed in the center of the symphysis at a safe distance from the tooth
roots. Biomechanically, one compression plate in the center (neutral zone) of
the mandible is sufficient to neutralize all forces within a normal range.
• The use of a tension band splint or at least a bridal wire is strongly
recommended to neutralize distraction forces at the superior border
of the mandible
• LAG SCREW OSTEOSYNTHESIS: Typically two 2.4 mm lag screws are
used to avoid torsion and for better stability, but one 2.4 mm lag
screw in combination with a tension band splint can be sufficiently
rigid.
BODY AND ANGLE FRACTURES
• Miniplate osteosynthesis in the lateral body is typically performed
transorally with a single miniplate in the center of the mandible
(neutral zone), and with monocortical screw insertion.
• In the angle, a miniplate is typically placed in the region of the
superior border (tension zone), either on the oblique ridge from a
transoral approach, or the superior lateral surface of the mandible
with the help of transbuccal instrumentation or an angulated
screwdriver
• In case of reduced bone buttress, some surgeons prefer using two
miniplates, one at the superior and one at the inferior border of the
mandible, with a minimum of two screws on either side of the
fracture.
• If greater stability is required, a load-sharing compression plate
osteosynthesis can be performed. Compression plate osteosynthesis
is performed at the inferior border of the mandible; screw fixation is
bicortical.
• This type of osteosynthesis typically creates distracting forces at the
superior border of the mandible and the lingual surface. To avoid
superior gap formation, tension banding must be performed.
• Lag screw fixation is another technique to perform loadsharing
fixation. Typically lag screw fixation is indicated for fractures with
oblique surfaces. To stabilize these, multiple lag screws (at least two)
may be used in place of a stabilization plate.
Coronoid Process fractures
• Fractures of the coronoid process are relatively uncommon. It is
generally accepted that they account for approximately 1% of all
mandible fractures. The coronoid process is infrequently fractured
because it is protected by the zygomatic arch.
• A diagnosed coronoid fracture is an indication for the surgeon to look
for an associated zygomatic arch fracture.
• Restricted mouth opening – common – inappropriate managements
causes its adhesion to to surrounding tissue -> Jacob’s disease
The significantly displaced coronoid process can be
pulled in a cephalad direction, occasion ally into the infratemporal fossa, by the
temporalis muscle.
Coronoid fracture may manifest as swelling below the zygomatic arch
and soft tissue swelling and ecchymosis in the retromolar
trigone region. Limited mouth opening, malocclusion,
and facial collapse may occur when accompanied by other facial
fractures.

Fractures with minimal displacement can be

managed with a soft diet and mouth opening
exercises

Fresh, linear coronoid fractures with minimal displacement or

clinical symptoms can be managed conservatively with the goal of avoiding osseous
adhesions.
• Surgery may be indicated for a)significant displacement or b)
candidates unsuited to prolonged IMF.
• Traditional approaches – extraoral and intraoral incisions.
• Preauricular incisions carry high risk of CN VII injury
• The surgical approach must provide direct visualization and adequate
exposure of the fractured bone segments to ensure anatomic
reduction of the fracture before rigid internal fixation.
RETROMANDIBULAR APPROACH
Performed through the anterior border of the parotid gland, which allows one to
enter the fracture site between the upper and lower buccal branches or between
the zygomatic and upper buccal branches of the facial nerve to perform ORIF.

The anatomic basis of this approach is that there is a safe zone on top of the
masseter muscle near the anterior border of the parotid gland.

Through this safe zone, adequate exposure of the condyle and coronoid process
can be achieved without jeopardizing the facial nerve branches or injuring the
parotid.
• Watertight closure of the parotid capsule using resorbable sutures
will help prevent salivary leak. A round bulb suction drain can once
again aid in the elimination of dead space and avoid seroma or
hematoma formation. A pressure dressing can also aid in hemostasis
and prevention of a salivary leak. Platysma is reapproximated and skin
closed with running nonresorbable, monofilament suture.
References
• Oral and Maxillofacial Trauma, Volume 2; Raymond J. Fonseca (Editor), Robert V. Walker (Editor)
• Rowe and Williams’ Maxillofacial Injuries, Volume 1
• Peterson’s Principles of Oral and Maxillofacial Surgery; Miloro, Ghali
• Internal Fixation of the Mandible: A Manual of AO/ASIF Principles; Bernd Spiessl
• Boffano P, et al., Fractures of the mandibular coronoid process: A two centres study, Journal of
Cranio-Maxillo Facial Surgery (2014), http://dx.doi.org/10.1016/j.jcms.2014.03.025
• L. Shen, J. Li, P. Li, J. Long, W. Tian: Mandibular coronoid fractures: Treatment options. Int. J.
Oral Maxillofac. Surg. 2013; 42: 721–726.
• Cornelius, C. P., Audigé, L., Kunz, C., Rudderman, R., Buitrago-Téllez, C. H., Frodel, J., & Prein, J.
(2014). The Comprehensive AOCMF Classification System: Mandible Fractures- Level 2
Tutorial. Craniomaxillofacial trauma & reconstruction, 7(Suppl 1), S015–S30. doi:10.1055/s-
0034-1389557