DELAYED FACIAL PALSY AFTER ACOUSTIC NEUROMA RESECTION - THE ROLE OF VIRAL REACTIVATION

Delayed facial palsy after acoustic neuroma resection may occur in up to 15% of cases. Prognosis is generally good if the palsy does not pro gress to total paralysis. However, a delayed palsy with subsequent tot al paralysis has a more variable final outcome, which ranges from norm al function to permanent total paralysis. This delayed paralysis has b een attributed to edema from surgical manipulation of the facial nerve . Steroids and intraoperative decompression of the meatal foramen have been used with some success, but some cases remain refractory to thes e measures. Herpes simplex virus and varicella-zoster virus are ubiqui tous in the population and remain in a latent state in neural ganglia. These viruses are reactivated during times of stress. Trigeminal nerv e surgery (partial sensory rhizotomy and microvascular decompression) stimulates reactivation of herpes simplex with manifestations in the s ensory distribution of the trigeminal nerve in 38-94% of procedures. P revention of this reactivation has been demonstrated in placebo-contro lled trials by using prophylactic acyclovir. We present a patient who underwent translabyrinthine resection of an intracanalicular acoustic neuroma and in whom developed otalgia, vesicles on the ear canal and t he ipsilateral buccal mucosa, and progressive facial palsy the week af ter surgery. Serologic evaluation confirmed the diagnosis of herpes te ster oticus. Reactivation of latent virus apparently occurred as a res ult of surgical manipulation of the facial nerve. This parallels viral reactivation seen in trigeminal nerve surgery. We propose a new theor y for an additional cause of delayed facial palsy after acoustic neuro ma resection-reactivation of latent herpesvirus resulting from surgica l trauma. Acyclovir should be evaluated in clinical trials for a proph ylactic role in patients undergoing acoustic neuroma resection or a th erapeutic role in patients in whom a delayed postoperative facial pals y develops.