Residency · Residency · Plastic Surgery

Maxillofacial Fracture Principles: Mandible and Midface

Introduction

Maxillofacial fractures are common in trauma, resulting from motor vehicle accidents, assaults, falls, and sports injuries. The plastic surgeon must understand facial buttress anatomy, fracture classification, occlusion, and principles of rigid fixation. Goals of treatment: restore pre-injury occlusion, re-establish facial projection and width, and preserve or restore function (mastication, vision, airway). Treatment has evolved from closed reduction and prolonged maxillomandibular fixation (MMF) toward open reduction and internal fixation (ORIF) with titanium plating systems.

Mandible Fractures

Anatomy

The mandible is a U-shaped bone; the only mobile bone of the facial skeleton. Anatomic regions: symphysis/parasymphysis, body, angle, ramus, coronoid process, condylar process (neck, subcondylar, intracapsular). Weakest points: angle (third molar region), condylar neck, mental foramen region, canine region. Inferior alveolar nerve (V3 branch): enters the mandibular foramen, courses through the body, exits at the mental foramen; at risk in body and parasymphysis fractures.

Muscles of mastication create displacement forces: Masseter, medial pterygoid, temporalis: elevate the mandible (close the jaw). Lateral pterygoid: protrudes the condyle; displaces condylar fractures anteromedially. Mylohyoid, geniohyoid, digastric, genioglossus: depress the mandible; pull fragments inferiorly and posteriorly.

Classification

By location: symphysis (3%), parasymphysis (14-20%), body (21-25%), angle (23-31%), ramus (3%), condyle (18-36%), coronoid (1-2%). Favorable vs. unfavorable: determined by whether muscle pull tends to reduce (favorable) or displace (unfavorable) the fracture. Simple (closed) vs. compound (open — communicating with skin or oral mucosa; most mandible fractures are compound through the gingiva). Most patients have at least two fracture sites (mandible acts as a ring structure).

Clinical Evaluation

Malocclusion is the most sensitive finding; patients report "my bite feels off". Step deformity along the inferior border; pain on palpation; mobility at fracture site. Numbness of the lower lip (inferior alveolar nerve injury): pathognomonic for body/parasymphysis fracture. Tongue blade bite test: patient bites on a tongue blade while examiner twists it; inability to hold suggests mandible fracture (negative predictive value >95%). Intraoral examination: gingival lacerations, hematoma in floor of mouth, dental injuries.

Imaging

Panoramic radiograph (Panorex): best single view for mandible fractures; shows entire mandible on one film. CT scan with 3D reconstruction: gold standard; identifies condylar and coronoid fractures missed on Panorex. Plain films (PA mandible, lateral oblique, Towne view): historical but largely replaced by CT.

Treatment Principles

Closed Reduction and MMF

Indicated for: nondisplaced or minimally displaced fractures, favorable fracture patterns, condylar fractures (selected), edentulous patients (some). Arch bars (Erich arch bars): wired to teeth; upper and lower jaw secured together with elastics or wires. MMF duration: 4-6 weeks; wire cutters must accompany patient at all times (airway emergency). IMF screws: self-drilling titanium screws placed into alveolar bone; alternative to arch bars; faster application, less risk of needlestick.

Open Reduction and Internal Fixation (ORIF)

Indicated for: displaced fractures, unfavorable fracture patterns, bilateral fractures, fractures with concomitant midface fractures. Champy's ideal osteosynthesis lines: placement of miniplates along lines of tension. Symphysis/parasymphysis: two plates (one at inferior border, one at subapical region) or single locking plate at inferior border. Body: one plate at inferior border; may add tension band plate at superior border.

Angle: single miniplate along the external oblique ridge (Champy technique) or two miniplates. Load-bearing fixation: large reconstruction plate at the inferior border; used for comminuted fractures, bone loss, pathologic fractures. Load-sharing fixation: smaller plates that share load with bone; used for simple fractures with bone-to-bone contact.

Condylar Fractures

Most controversial area of mandible fracture management. Closed treatment (MMF): historically preferred; indicated for intracapsular fractures, nondisplaced subcondylar fractures, children (risk of growth center damage), edentulous patients. Open treatment (ORIF): increasingly favored for displaced subcondylar fractures; indications include bilateral condylar fractures with open bite, condylar displacement into middle cranial fossa, inability to achieve occlusion with MMF, lateral extracapsular displacement. Approaches: preauricular, retromandibular (Hinds/Risdon), submandibular, endoscopic-assisted transoral.

<image>Anatomical illustration of the mandible showing common fracture locations and Champy's ideal lines of osteosynthesis. The mandible is shown in an anterolateral three-quarter view with the common fracture sites highlighted in different colors: symphysis and parasymphysis in red, body in orange, angle in yellow, ramus in green, condylar process in blue, and coronoid process in purple. Percentage frequencies are labeled at each site. Champy's ideal osteosynthesis lines are superimposed as dashed lines: along the external oblique ridge at the angle region, along the superior and inferior borders of the body, and two lines at the parasymphysis region (one subapical tension band and one inferior border). Small titanium miniplates are shown positioned along these ideal lines at representative fracture sites. The inferior alveolar nerve canal is shown coursing through the body with exit at the mental foramen.</image>

Midface Fractures

Buttress Anatomy

The midface is supported by a system of vertical and horizontal buttresses (thick bone) separated by thin bone (sinuses). Vertical buttresses (resist masticatory forces): Nasomaxillary (medial): from piriform aperture to frontal bone. Zygomaticomaxillary (lateral): from zygoma through lateral maxilla to alveolus.

Pterygomaxillary (posterior): pterygoid plates to posterior maxilla. Horizontal buttresses: frontal bar, infraorbital rim, maxillary alveolus, hard palate. Reconstruction principle: restore vertical buttress height and projection; horizontal buttresses restore facial width.

Le Fort Classification

In practice, Le Fort fractures are rarely symmetric; patients often have different Le Fort levels on each side (mixed pattern).

In practice, Le Fort fractures are rarely symmetric; patients often have different Le Fort levels on each side (mixed pattern).

Palatal Fractures

Sagittal or parasagittal fractures of the hard palate. Widen the maxillary arch; cause malocclusion. Treatment: palatal splint or ORIF of palate and reduction of maxillary width.

Panfacial Fractures

Involve upper face (frontal), midface (Le Fort, NOE, ZMC), and lower face (mandible) simultaneously. Reconstruction sequence controversial: "bottom-up and outside-in" (restore mandibular width first, then midface, then upper face) vs. "top-down and outside-in" (start with stable cranial base and zygomatic arches, then midface, then mandible). Key: restore facial width (zygomatic arches), height (vertical buttresses), and projection (anterior-posterior). Establish occlusion with MMF; then plate fractures sequentially.

<image>Illustration of the Le Fort fracture classification showing three views of the facial skeleton. The first panel shows a frontal view of the skull with Le Fort I fracture line drawn in green running horizontally through the maxilla above the tooth roots, through the lateral nasal walls, and through the pterygoid plates bilaterally. The second panel shows the Le Fort II fracture line in blue running from the nasofrontal suture area diagonally through the medial orbital walls, across the infraorbital rims, and down through the anterior maxillary walls to the pterygoid plates, forming a pyramidal shape. The third panel shows the Le Fort III fracture line in red running through the nasofrontal suture, across the medial and lateral orbital walls, through the zygomaticofrontal sutures, across the zygomatic arches, and through the pterygoid plates, completely separating the facial skeleton from the cranial base. Each panel labels key anatomic landmarks: nasofrontal suture, infraorbital rim, zygomaticofrontal suture, zygomatic arch, and pterygoid plates.</image>

Surgical Approaches

Intraoral (gingivobuccal sulcus): access to mandible body, parasymphysis, anterior maxilla, zygomaticomaxillary buttress. Coronal (bitemporal): wide exposure of upper and midface; access to zygomatic arches, frontal bone, NOE complex, orbital roof. Subciliary/subtarsal/transconjunctival: access to infraorbital rim and orbital floor. Upper eyelid crease (blepharoplasty incision): access to zygomaticofrontal suture and lateral orbital wall.

Preauricular/endaural: access to condylar head and TMJ. Retromandibular (Risdon): access to subcondylar region, ramus, angle. Existing lacerations: always use when appropriate.

Complications

Malocclusion: most common functional complication; inadequate reduction or plate failure. Hardware infection/exposure: 5-10%; may require hardware removal after fracture healing. Nonunion/malunion: risk factors include infection, inadequate fixation, mobility at fracture site. Inferior alveolar nerve injury: numbness of lower lip; occurs in 30-40% of body/parasymphysis fractures; most resolve within 6 months.

TMJ dysfunction: pain, limited opening, ankylosis (especially after condylar fractures). Enophthalmos/diplopia: inadequate orbital floor reconstruction in midface fractures. Tooth root injury: from screw placement; maintain 5 mm from tooth apices.

Key Clinical Pearls

Malocclusion is the most reliable clinical finding in mandible fractures; always check occlusion in any facial trauma patient and compare to the patient's baseline (ask about pre-injury bite). The mandible behaves as a ring structure; always search for a second fracture when one is identified (most commonly contralateral condyle with parasymphysis fracture). In midface fractures, restoration of the vertical buttresses is the key to re-establishing facial height and projection; plating only horizontal buttresses leads to midface shortening. Condylar fractures in children should generally be treated closed; the condyle has remarkable remodeling potential in the growing skeleton, and ORIF risks injury to the growth center. Panfacial fractures require systematic reconstruction of facial width, height, and projection; establishing the mandibular arch width and occlusion early provides a stable foundation for midface reconstruction.

References

• Champy M, Loddé JP, Schmitt R, Jaeger JH, Muster D. Mandibular osteosynthesis by miniature screwed plates via a buccal approach. J Maxillofac Surg. 1978;6(1):14-21.
• Manson PN, Crawley WA, Yaremchuk MJ, Rochman GM, Hoopes JE, French JH Jr. Midface fractures: advantages of immediate extended open reduction and bone grafting. Plast Reconstr Surg. 1985;76(1):1-12.
• Ellis E 3rd, Throckmorton GS. Treatment of mandibular condylar process fractures: biological considerations. J Oral Maxillofac Surg. 2005;63(1):115-134.
• Markowitz BL, Manson PN, Sargent L, et al. Management of the medial canthal tendon in nasoethmoid orbital fractures: the importance of the central fragment in classification and treatment. Plast Reconstr Surg. 1991;87(5):843-853.

Read this lecture as Markdown