Purpose: The object of the present study was to review a series of surgically removed vestibular schwannoma tumours to establish the incidence of delayed facial palsy and to evaluate the course of recovery according to the possible etiology (surgical postoperative edema or viral reactivation) with reference to the time of onset.
Materials and methods: The study group was composed of 98 patients with vestibular schwannoma. Sex, age, location, and extent of tumour and postoperative complications were all taken into consideration in the final evaluation. The course of each patient's postoperative facial function was graded according to House and Brackmann's six-grade scale. The incidence and the time of onset of the delayed facial palsy were also evaluated.
Results: The deterioration in the facial function was found to be delayed in 25 of the 98 patients (26%); of these, it occurred in the first 5 days after surgery in 11 cases, between 6 and 13 days in 10 cases, and after 15 days in 14 patients. The incidence rate of the delayed facial dysfunction was not influenced by age, sex, or the size of the tumour. The prognosis of the facial dysfunction was favourable in the majority of cases, and, in fact, there were only five grade III to IV cases 1 year later. Facial dysfunction was over grade III in the majority of the latter five cases, and the period of recovery was long.
Conclusions: Eighty percent of our patients with delayed facial palsy following vestibular schwannoma resection were classified as having excellent or good function. In the remaining patients who had a less favourable recovery, the palsy was more severe, and the onset occurred after some time. This seems to agree with those who are of the opinion that the complication is due to viral reactivation. In these patients, it is advisable to start aggressive medical therapy with antiviral agents such as acyclovir as soon as possible.