Management of Facial Paralysis

Anatomy & Etiology - Nerve Nuances

• Facial Nerve (CN VII): Motor, parasympathetic, sensory.
  • Segments: Intracranial, Meatal, Labyrinthine, Tympanic, Mastoid, Extratemporal.
  • Branches: GSPN, N. to Stapedius, Chorda Tympani. Extratemporal: Temporal, Zygomatic, Buccal, Marginal Mandibular, Cervical (📌 To Zanzibar By Motor Car).
• Etiology:
  • Bell's Palsy (most common).
  • Trauma (Temporal bone #).
  • Infections (Ramsay Hunt, Lyme).
  • Tumors (Acoustic neuroma, Parotid).

⭐ Bell's Palsy is the most common cause of unilateral facial paralysis, accounting for ~70% of cases.

Clinical Evaluation - Face Facts First

• History: Onset (sudden/gradual), duration, progression. Associated: otalgia, vesicles (Zoster), hearing loss, tinnitus, vertigo, dry eyes/mouth (sicca), taste changes (dysgeusia), trauma, prior episodes.
• Examination:
  • Systemic: Parotid masses, skin lesions.
  • Cranial Nerves: Focus on V, VIII; also VII, IX, X, XI, XII.
  • Facial Nerve Detail:
    • Symmetry: At rest (e.g., nasolabial fold) and with movement (forehead wrinkle, eye closure, smile, pucker).
    • Bell's phenomenon: Eye rolls up/out on attempted closure.
    • Synkinesis, hemifacial spasm, contractures, crocodile tears (gustatory lacrimation).
• Grading: Quantify severity.
  • House-Brackmann Scale: Standard.

⭐ House-Brackmann Grade III signifies moderately severe dysfunction with obvious, disfiguring weakness but some movement; Grade VI is total paralysis.

Investigations - Nerve Navigators

• Topodiagnostic Tests (Conceptual):
  • Schirmer's, Stapedial reflex, Taste, Salivary flow.
• Electrophysiological Tests:
  • ENoG (Electroneurography):
    • Compares Compound Muscle Action Potential (CMAP): affected vs. normal side.

    • 90% degeneration by 3 weeks (ideally ~14 days) → poor prognosis; consider surgery.

  • EMG (Electromyography):
    • Fibrillation potentials (denervation): after 10-21 days.
    • Polyphasic potentials: reinnervation signs.
• Imaging: CT/MRI for suspected tumor, trauma, central cause.

⭐ ENoG showing > 90% degeneration of nerve fibres vs. normal side by 3 weeks (ideally ~14 days) post-onset is a key indicator for surgical intervention in complete paralysis (e.g., Bell's Palsy, trauma).

Management Options - Fixes & Functions

• Medical (Acute Phase):
  • Eye Care: Essential! Lubricants, patching, taping. Temporary tarsorrhaphy for corneal protection.
  • Steroids: Prednisolone ($1mg/kg/day$) for Bell's Palsy, start within 72h.
  • Antivirals: For Ramsay Hunt; +/- severe Bell's with steroids.
• Surgical (Timing is CRUCIAL):
  • Early Interventions (<3 mo, nerve viable):
    • Facial Nerve Decompression (selected cases: trauma, Bell's >90% ENOG degeneration).
    • Direct Neurorrhaphy (end-to-end).
    • Interpositional Cable Grafts (e.g., Great Auricular, Sural for gaps).
  • Nerve Transfers (Neurotization, 3-18 mo for muscle reinnervation):
    • Hypoglossal-Facial (XII-VII) 📌 "Lick & Smile!"
    • Masseteric-Facial (V3-VII).
    • Cross-Facial Nerve Graft (CFNG).
  • Late Reanimation (>1.5-2 yrs or significant muscle atrophy):
    • Dynamic: Temporalis/Masseter regional muscle transfer; Gracilis free flap (smile).
    • Static: Slings (fascia lata), brow lift, eyelid procedures for symmetry.
• Synkinesis Management:
  • Botulinum toxin, physiotherapy, selective neurectomy/myectomy.

⭐ Early corticosteroids (Prednisolone, within 72h) are key for Bell's Palsy recovery.

High‑Yield Points - ⚡ Biggest Takeaways

• Nerve repair/grafting is optimal within 12-18 months post-injury for functional recovery.
• House-Brackmann scale is the standard for grading facial nerve deficit severity.
• Bell's Palsy: Treat promptly with corticosteroids; prioritize corneal protection and eye care.
• Traumatic nerve transection: Demands urgent surgical exploration and microneural repair/grafting.
• Dynamic reanimation (e.g., temporalis transfer, gracilis flap) restores active facial movement.
• Static procedures (e.g., slings, tarsorrhaphy) provide support and improve resting symmetry.
• Botulinum toxin effectively manages synkinesis and reduces contralateral facial muscle overactivity.