Facial Nerve Repair in Maxillofacial Surgery

Facial nerve damage is a complex clinical condition that often falls under the scope of Oral and Maxillofacial Surgery (OMS), particularly when it arises from trauma, surgical complications, or tumour resection. The facial nerve, also known as the seventh cranial nerve, plays a crucial role in facial movement, expression, and certain sensory functions. It is responsible for motor control of the muscles of facial expression, including those that help us smile, frown, blink, and speak. It also carries taste sensations from the anterior two-thirds of the tongue and contributes to tear and saliva production. Damage to this nerve can result in facial paralysis, asymmetry, drooling, speech difficulties, and social or psychological distress.

When facial nerve damage occurs, timely surgical intervention can help restore partial or complete nerve function. The procedure can:

• Improve facial symmetry and expressions
• Restore oral competence
• Reduce the risk of ocular complications (e.g., exposure keratitis)
• Alleviate chronic pain or discomfort
• Enhance social interactions and psychological well-being

Unlike standard OMS procedures focused on structural corrections (like fractures or dental realignment), facial nerve repair prioritizes functional restoration, which requires more nuanced microsurgical techniques.

IMPORTANT TO NOT: IF THE BELOW COMPLICATIONS ARISE, URGENT MEDICAL CARE IS REQUIRED.

• Sudden facial paralysis after trauma
• Open facial wounds with visible nerve laceration
• Progressive facial weakness following tumour growth
• Severe pain or rapid-onset dysfunction after surgery
• Inability to close the eye on the affected side
• Drooping of the mouth or eyelid
• Loss of forehead movement
• Altered taste or hypersensitivity to sound (hyperacusis)
• Facial asymmetry progressing rapidly

Why Cuba

Surgical management of facial nerve damage in Cuba, within the domain of oral and maxillofacial surgery, centers on restoring neuromuscular function, preserving facial symmetry, and preventing long-term functional and psychosocial complications. Whether due to trauma, tumour resection, or complications during maxillofacial procedures, Cuban surgical teams are trained to identify and manage facial nerve injuries with a focus on anatomical precision and nerve preservation.

The approach emphasizes meticulous dissection near high-risk zones such as the parotid region, mandibular ramus, and zygomatic arch—areas where the facial nerve or its branches may be exposed or at risk. Safeguarding critical neurovascular structures is a top priority, and when injury is unavoidable, microsurgical repair or nerve grafting is employed to reestablish continuity and restore motor function.

Facial Nerve Repair in Oral and Maxillofacial Context

Facial nerve damage managed by oral and maxillofacial surgeons usually results from:

• Facial trauma (e.g., mandibular fractures, blunt injuries)
• Tumour resection in the parotid gland or other facial structures
• Complications from third molar extractions or orthognathic surgeries
• Benign or malignant tumours compressing or infiltrating the nerve
• Infections and inflammatory lesions impacting adjacent structures

Classification and Types of Facial Nerve Injuries

Facial nerve injuries are categorized based on the degree of physical damage to the nerve and the resulting functional impairment.

• Mild Injuries
  • Involve temporary disruption of nerve signaling
  • Caused by swelling, compression, or mild trauma
  • Usually self-limiting with full spontaneous recovery expected

• Moderate Injuries
  • Partial disruption of nerve fibers
  • May result in prolonged weakness or incomplete facial movement
  • Surgical intervention might be necessary if function does not return over time

• Severe Injuries
  • Involve significant structural damage or loss of nerve continuity
  • Often result in persistent or complete facial paralysis
  • Require microsurgical repair, nerve grafting, or nerve transfer to restore function

• Complete Nerve Transection
  • The nerve is fully severed, typically from major trauma or tumor resection
  • No chance of spontaneous recovery
  • Demands complex reconstructive surgery to regain motor control

Each level of injury affects prognosis, urgency of treatment, and the specific surgical approach required for optimal facial function recovery.

Causes of Facial Nerve Damage

There are several underlying causes that result in facial nerve damage, including:

• Blunt trauma or penetrating injuries
• Surgical complications during parotidectomy, mandibular fracture repair, or tumor excision
• Tumor compression or infiltration
• Post-radiation fibrosis
• Iatrogenic injury from cosmetic or dental procedures
• Congenital anomalies or developmental malformations

Pre-Surgical Diagnosis and Imaging

Before proceeding with facial nerve repair, a thorough clinical and radiologic workup is essential to determine the extent of the injury, guide surgical planning, and establish a functional baseline. Key diagnostic tools and assessments include:

• Comprehensive Clinical Examination
  • Evaluates facial symmetry, voluntary movement, and muscle tone
  • Assesses ocular function (such as blink reflex and lid closure) and oral competence
  • Helps identify muscle groups affected and maps out potential nerve involvement

• Electroneurography (ENoG)
  • Measures the electrical conduction of the facial nerve
  • Assesses the degree of axonal degeneration
  • Most useful within the first two weeks after injury to predict recovery potential

• Electromyography (EMG)
  • Evaluates the electrical activity of facial muscles
  • Detects evidence of reinnervation or ongoing denervation
  • Guides the timing of surgery by indicating whether spontaneous nerve regeneration is occurring

• Magnetic Resonance Imaging (MRI)
  • Provides detailed images of soft tissues, including the facial nerve pathway
  • Essential for assessing tumour involvement, nerve inflammation, or edema
  • Identifies compression or infiltration by benign or malignant lesions

• Computed Tomography (CT) Scans
  • Ideal for evaluating bony trauma, fractures of the temporal bone, or skull base
  • Helpful in identifying displaced bone fragments near the facial nerve canal
  • Often used in acute trauma cases to assess surgical accessibility

• Facial Function Grading Systems
  • Standardized scales are used to document baseline nerve function and monitor progress post-treatment
  • Provide objective measures for assessing treatment efficacy over time
  • Aid in communicating clinical status between multidisciplinary team members

Surgical Treatment of Facial Nerve Damage

The surgical management of facial nerve damage requires a highly individualized approach, guided by the severity, location, and duration of the injury, as well as the patient’s overall functional and aesthetic needs.

Candidates for facial nerve surgery typically include:

• Patients with recent facial trauma and evident nerve damage
• Individuals with tumors causing facial nerve dysfunction
• Patients with post-surgical facial paralysis
• Children or adults with congenital nerve dysfunction eligible for functional restoration
• Patients with incomplete spontaneous recovery after 6–12 months of observation

Contraindications may include severe comorbidities, advanced age without significant distress, or refusal of surgical intervention.

Surgical approach includes: 

• Preoperative Planning:
  • Confirm diagnosis
  • Map nerve pathways
  • Plan access route and approach

• Anesthesia and Positioning:
  • General anesthesia is standard
  • Proper head positioning to optimize visibility

• Surgical Exposure:
  • Incision placement to avoid additional nerve injury
  • Dissection down to the injured segment

• Nerve Assessment:
  • Determine the extent of damage
  • Preserve viable nerve tissue

• Repair Techniques:
  • Primary neurorrhaphy (direct end-to-end repair) when tension-free
  • Nerve grafting using donor nerves like the sural or great auricular nerve
  • Nerve transfer (e.g., hypoglossal-facial or masseteric-facial transfer) in long-standing paralysis
  • Facial reanimation using muscle flaps (e.g., gracilis transfer) for chronic cases

• Microsurgical Closure:
  • Use of operating microscope
  • Suture repair with ultrafine non-absorbable threads

• Postoperative Care:
  • Eye protection if eyelid closure is compromised
  • Physical therapy for facial muscle retraining
  • Follow-up imaging and nerve function assessment

Minimally Invasive vs. Open Surgical Approaches

• Minimally Invasive Techniques may be used for nerve decompression or endoscopic exploration but are limited in complex repairs.

• Open Surgical Approaches remain the gold standard for full nerve exposure, repair, and grafting. These allow better visualization and control during intricate microsurgery.