HSC Section 3 - Trauma, Critical Care and Sleep Medicine

Surgical Management of Acute Facial Palsy

Return of Facial Nerve Function and Follow-up For both Bell palsy and temporal bone fracture, patients should be counseled that any recovery of facial nerve function will be delayed, despite exceptional reports of imme- diate improvement in facial nerve function following decompression. 49–51 In most cases, there are signs of recovery 3 to 6 months postoperatively; however, synkinesis can develop up to 12 months following injury. A large number of patients with Bell palsy treated with decompression eventually experience good recovery (HB 1 or 2) of facial nerve function. 2 In cases of traumatic injury requiring primary neurorrhaphy or grafting, the restoration of facial tone and voluntary movement can be expected, albeit with synkinesis. As facial nerve function recovers, aberrant innervation of the facial nerve may affect the ocular system in 3 ways. 47 Gustatory lacrimation, or crocodile tears, can occur as fibers to the submandibular and sublingual glands aberrantly innervate the lacrimal gland, causing tearing during chewing. Synkinesis may result from axons reinnervating different muscles than those originally served, resulting in aberrant twitching or move- ment of the eyelid with lower face movement, and vice versa. Hypertonicity may result in the affected side contracting at rest despite decreased dynamic function. Complications of Facial Nerve Surgery The potential complications of facial nerve surgery depend on the approach used. Hearing preservation via anMCF approach requires detailed knowledge of the unforgiv- ing middle fossa anatomy. In our experience, intraoperative image guidance offers limited value because the margin of error in the navigation system is frequently larger than the margin of error afforded by the anatomy, especially in the lateral IAC. The rate of CSF leak following acoustic neuroma excision via an MCF approach is 2% to 6% 52 but is lower in cases of facial nerve decompression because the cerebellopontine angle is not widely opened. Seizure, stroke, hematoma (epidural/subarachnoid/paren- chymal), andmeningitis are also potential risks, albeit extremely rare. Transient aphasia has been observed only rarely over 30 years of experience at our institution, presumably from retraction on the dominant temporal lobe; full recovery occurred in each case. Bell palsy or traumatic facial nerve injury are two common causes of acute facial palsy. Bell palsy accounts for most acute facial palsy cases, and most patients with Bell palsy completely recover with medical therapy alone. However, patients with com- plete paralysis who meet electrophysiologic criteria have a poor prognosis with med- ical therapy alone and may benefit from facial nerve decompression via an MCF approach. Patients with acute facial palsy from traumatic injury may be candidates for decompression via an MCF or translabyrinthine approach based on hearing status. Available evidence suggests that, for those meeting criteria, surgical decompression improves that chance of recovery. However, detailed counseling is required for an intervention plan customized to each patient. SUMMARY

REFERENCES

1. Peitersen E. Bell’s palsy: the spontaneous course of 2,500 peripheral facial nerve palsies of different etiologies. Acta Otolaryngol Suppl 2002;(549):4–30 . 2. Gantz BJ, Rubinstein JT, Gidley P, et al. Surgical management of Bell’s palsy. Laryngoscope 1999;109(8):1177–88. Available at: https://www.ncbi.nlm.nih.gov/ pubmed/10443817 .

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