Post-traumatic Maxillofacial Defects

Definition

Aims of management

1. Save life and secure the airway.
2. Control hemorrhage and treat associated head, cervical spine, thoracic and limb injuries.
3. Preserve vision, hearing, facial nerve function, teeth and viable tissue.
4. Restore facial skeletal framework, height, width, projection and symmetry.
5. Re-establish dental occlusion and masticatory function.
6. Restore oral competence, speech, swallowing and nasal airway.
7. Provide stable soft-tissue cover and separate oral, nasal, sinus and cranial cavities where required.
8. Achieve acceptable aesthetic reconstruction with minimal donor-site morbidity.
9. Provide dental, prosthetic, psychological and social rehabilitation.

Classification

1. According to tissue involved

• Soft-tissue defects: skin loss, laceration, avulsion, cheek, lip, nose, eyelid or ear loss.
• Hard-tissue defects: fracture with bone loss involving mandible, maxilla, zygoma, orbital rim/floor, nasal bones or frontal bone.
• Composite defects: combined loss of skin, mucosa, muscle, bone, teeth, cartilage, nerve or vessels.

2. According to anatomical site

• Mandibular defects
• Maxillary and palatal defects
• Midfacial or zygomaticomaxillary defects
• Orbital defects
• Nasal defects
• Lip and cheek defects
• Auricular defects
• Panfacial defects

3. According to time of presentation

• Acute defects: present at the time of injury.
• Secondary defects: malunion, non-union, infection, scar contracture, facial asymmetry, malocclusion, enophthalmos, fistula or loss of tissue after prior treatment.

4. According to wound contamination

• Clean
• Contaminated
• Infected or devitalized, especially after crush, farm, ballistic or blast trauma.

Initial assessment and emergency management

A. Airway with cervical spine protection

• Clear suctionable material and remove loose dentures or teeth.
• Give high-flow oxygen.
• Use jaw thrust while protecting the cervical spine.
• Orotracheal or nasotracheal intubation may be possible depending on injury pattern.
• In severe midface disruption, massive bleeding or penetrating trauma, a surgical airway, usually cricothyroidotomy followed when appropriate by tracheostomy, may be needed.
• Do not allow facial injuries to distract from associated cervical spine or intracranial injury.

B. Breathing and circulation

• Assess for thoracic injury and shock.
• Control external bleeding with direct pressure, packing, vessel ligation or embolization where necessary.
• Establish IV access, resuscitate with blood products when indicated, and correct coagulopathy.
• Major shock is uncommon from facial trauma alone unless there is obvious severe external hemorrhage. ROSEN's Emergency Medicine, p. 401.

C. Disability and exposure

• Glasgow Coma Scale, pupils and neurological examination.
• Look for traumatic brain injury and cervical spine injury.
• Examine all wounds carefully for contamination, foreign bodies, tissue viability and associated injuries.

D. Important specialist assessment

• Ophthalmology: visual acuity, pupillary responses, ocular movement, diplopia, globe injury, intraocular pressure and fundus.
• ENT/neurosurgery: CSF rhinorrhea, skull-base injury, hearing loss and intracranial extension.
• Dental/maxillofacial assessment: occlusion, mobility of facial segments, tooth injury, mucosal tears and mandibular movement.

Investigation

1. Clinical photographs before treatment, when feasible.
2. Plain radiographs may be used in selected settings, but have limited value in complex trauma.
3. Thin-slice CT scan of facial bones with axial, coronal and sagittal reconstruction is the investigation of choice.
4. CT angiography when vascular injury is suspected.
5. MRI for selected soft-tissue, optic nerve, intracranial or temporomandibular joint injuries.
6. Dental radiographs or orthopantomogram for dentoalveolar and mandibular evaluation.
7. Preoperative 3D CT models, virtual surgical planning and patient-specific implants may assist complex secondary reconstruction.

General principles of definitive reconstruction

1. Thorough wound toilet and conservative debridement

• Copious irrigation with saline.
• Remove foreign material, devitalized tissue, dirt, teeth fragments and nonviable bone.
• Debride conservatively because facial tissues have rich blood supply and tissue that appears doubtful may survive.
• Obtain cultures where wounds are grossly contaminated or infected.
• Give tetanus prophylaxis and appropriate antibiotics for contaminated wounds or compound fractures.

2. Preserve and replace tissue on a like-for-like basis

• Skin with skin
• Oral lining with mucosa or thin pliable flap
• Bone with vascularized or non-vascularized bone as indicated
• Cartilage with cartilage
• Muscle and sphincters with functional muscle repair
• Teeth with dental rehabilitation or implants.

3. Restore skeletal framework before final soft-tissue contour

• Mandible
• Zygomatic arches and zygomaticomaxillary complex
• Orbital rims and floors
• Maxillary buttresses
• Nasal support and central midface

4. Restore occlusion

• Establish pre-injury occlusion using remaining teeth, dental casts, arch bars, maxillomandibular fixation or occlusal splints.
• Reduce and fix fractures after occlusal alignment.
• Replace missing dentition later with removable prosthesis, fixed prosthesis or implants.

5. Repair in layers

• Mucosa
• Muscle, especially orbicularis oris in lip injuries
• Subcutaneous tissue
• Skin

6. Avoid tension and protect vascularity

• Use well-vascularized tissue.
• Avoid closure under tension.
• Provide adequate soft tissue over bone grafts, plates and implants.
• Use drains where required to prevent hematoma and infection.

Timing of reconstruction

Immediate reconstruction

• Patient is hemodynamically stable.
• Wound is clean or can be adequately debrided.
• There is exposed bone, airway compromise, open fracture, tissue avulsion or orbital emergency.
• Viable tissue is available for early repair.

Delayed or staged reconstruction

• The patient has life-threatening associated injuries.
• There is severe contamination, infection, uncertain tissue viability or major edema.
• There is extensive crush or ballistic injury.
• Multiple operations are needed.

Reconstruction according to defect

A. Soft-tissue defects

Small defects

• Primary closure after proper debridement, provided closure is tension-free.
• Local advancement, rotation or transposition flaps.
• Full-thickness skin grafts for selected superficial defects.

Larger defects

• Regional pedicled flaps:
  • Forehead flap for nasal defects
  • Nasolabial flap for cheek, nose and lip defects
  • Cervicofacial rotation flap for cheek and lower eyelid
  • Temporalis muscle flap for temporal, orbital or intraoral defects
  • Pectoralis major myocutaneous flap in selected large lower-face defects
• Free tissue transfer:
  • Radial forearm free flap for thin, pliable lining
  • Anterolateral thigh flap for larger soft-tissue volume
  • Scapular/parascapular flap when large skin and soft tissue are needed.

B. Mandibular defects

• Small, well-vascularized defect: reconstruction plate with cancellous bone graft may be used in selected clean defects.
• Segmental mandibular defect: vascularized bone flap is preferred, particularly in defects larger than about 5-6 cm, infected wounds, irradiated tissue or composite loss.
  • Fibula free flap: provides long bone segment, can be osteotomized and accepts dental implants.
  • Iliac crest free flap: provides greater bone height and soft-tissue bulk.
  • Scapular flap: useful where extensive skin and soft tissue are also missing.
• Temporary reconstruction plates may maintain continuity until definitive reconstruction.

C. Maxillary and palatal defects

• Small palatal defects: local palatal, buccal fat pad, facial artery musculomucosal or temporalis flap.
• Obturator prosthesis: useful in selected defects, especially where surgery is contraindicated or defect surveillance is needed.
• Larger maxillary or midface defects: free flap reconstruction such as fibula, scapula, iliac crest or osteocutaneous radial forearm flap, often combined with plates and implants.
• Extensive defects with loss of orbital support should be reconstructed to avoid inferior displacement of the globe and poor facial appearance. Scott-Brown's Otorhinolaryngology Head & Neck Surgery, Chapter 31.

D. Orbital defects

• Urgent management of globe rupture or optic nerve injury takes priority.
• Reconstruct orbital floor and medial wall using titanium mesh, porous polyethylene, resorbable implants or bone graft.
• Correct bony orbital rim and zygomatic position first.
• Assess globe position, ocular movement and diplopia postoperatively.

E. Nasal defects

• Re-establish nasal lining, skeletal/cartilaginous support and skin cover.
• Septal, auricular or costal cartilage grafts may be needed.
• Paramedian forehead flap is commonly used for major external nasal cover.
• Free flaps may be necessary in subtotal nasal loss.

F. Lip and cheek defects

• Small defects: primary closure.
• Moderate lip defects: local advancement or cross-lip flaps.
• Large full-thickness defects: local or free flap reconstruction with restoration of orbicularis function whenever possible.
• Cheek reconstruction requires separate consideration of skin cover, oral lining, buccal mucosa, parotid duct and facial nerve.

G. Auricular defects

• Small defects can be treated with local flaps and cartilage grafts.
• Major loss may require staged autologous costal cartilage reconstruction, alloplastic framework in selected patients, or auricular prosthesis.

Role of prosthetic rehabilitation

• Interim obturator
• Definitive obturator
• Removable or fixed dental prosthesis
• Implant-supported prosthesis
• Zygomatic implants in selected maxillary defects

Complications

Early

• Airway obstruction
• Hemorrhage and hematoma
• Wound infection
• Tissue necrosis
• Plate exposure
• CSF leak
• Visual loss or diplopia
• Salivary fistula
• Malocclusion

Late

• Facial asymmetry and contour deformity
• Malunion, non-union or osteomyelitis
• Trismus and temporomandibular joint dysfunction
• Enophthalmos, telecanthus or persistent diplopia
• Oroantral or oronasal fistula
• Nasal obstruction
• Scar hypertrophy and contracture
• Facial nerve weakness
• Loss of teeth and impaired mastication
• Psychological morbidity including anxiety, depression, post-traumatic stress symptoms and negative body image.

Rehabilitation and follow-up

• Wound healing and infection
• Occlusion and mandibular movement
• Vision and eye position
• Nasal airway and speech
• Bone union and plate status
• Need for secondary scar revision, fat grafting, contour augmentation or implant rehabilitation
• Psychological adjustment and return to work/social life

Conclusion