Surgical management of Bell's palsy

Objectives: Incomplete return of facial motor function and synkinesis conti nue to be long-term sequelae in some patients with Bell's palsy. The aim of this report is to describe a prospective study in which a well-defined sur gical decompression of the facial nerve was performed in a population of pa tients with Bell's palsy who exhibit the electrophysiologic features associ ated with poor outcomes. In addition, management issues related to Bell's p alsy including herpes simplex virus type1 etiology, the natural history, el ectrodiagnostic testing, and efficacy of surgical strategies are reviewed. Study Design and Methods: A multicenter prospective clinical trial was desi gned utilizing electroneurography (ENOG) and voluntary electromyography (EM G) to identify patients with Bell's palsy who would most likely develop poo r return of facial function, as suggested by Fisch and Esslen. Patients who displayed electrodiagnostic features of poor outcome, >90% degeneration on ENOG testing and no voluntary motor unit EMG potentials within 14 days of onset of total paralysis, were offered a surgical decompression of the faci al nerve through a middle cranial fossa surgical exposure, including the ty mpanic segment, geniculate ganglion, labyrinthine segment, and meatal foram en. Control subjects were those who displayed similar electrodiagnostic fea tures and time course. Results: Subjects who did not reach, >90% degenerati on on ENOG;within 14 days of paralysis all returned to House-Brackmann grad e I (n=48) or II (n=6) at 7 months after onset of the paralysis. Control su bjects self-selecting not to undergo surgical decompression when >90% degen eration on ENOG and no motor unit potentials on EMG were identified had a 5 8% chance of developing a poor outcome at 7 months after onset of paralysis (House-Brackmann grade III or TV [n=19]). A group with similar ENOG and EM G findings undergoing middle fossa facial nerve decompression exhibited Hou se-Brackmann grade I (n=14) or II (n=17) in 91% of the cases. An exact perm utation test confirmed that the surgical group had a significantly higher p roportion of patients with a good outcome (House-Brackmann grade I or II) ( P =.0002). Conclusion: Electroneurography in combination with voluntary EMG successfully identified patients who will most likely return to normal fro m those who had a greater chance of long-term sequelae from Bell's palsy. S urgical decompression medial to the geniculate ganglion significantly impro ves the chances of normal or near-normal return of facial function in the g roup that has a high probability of a poor result. Surgical decompression m ust be performed within 2 weeks of onset of total paralysis for it to be ef fective.