Postoperative functional preservation of facial nerve in cystic vestibular schwannoma.

OBJECTIVE: The goal of this study was to retrospectively analyze clinical and surgical data of a consecutive series of twenty-six patients with unilateral cystic vestibular schwannomas. METHODS: Tumors were classified as type A (central cyst) and type B (peripheral cyst), and as small (tumor diameter 3cm). All patients underwent microsurgical removal via retrosigmoid approach. The course of facial nerve (FN) was classified into anterior, anterior-inferior, anterior-superior and dorsal to the tumor's surface. RESULTS: Mean age was 53.5 years. Mean tumor size was 3.2 cm. Twenty-two cases were classified as type A and only 4 as type B. Total or near total resection (>95%) was achieved in 16 cases (61.5%), subtotal removal (90-95%) in 9 cases (34.6%), and partial removal (<90%) in 1 case (3.9%). Position pattern of FN was anterior-inferior in 10 cases (38.4%), anterior-superior in 10 cases (38.4%), anterior in 23.2% of cases. At hospital discharge, 9 (36%), 10 (38%), 3 (12%), 3 (12%) and 1 (4%) patients had a FN function of HB I-V, respectively; at final follow-up HB I, II, III and IV accounted respectively for 18 (72%), 6 (24%), 1 and 1 cases. At a follow-up ranging from 6 months to 10 years, a reoperation for growing of residue was never necessary. CONCLUSIONS: According to the literature and to the results of our series, microneurosurgery of cystic vestibular schwannomas is associated with good outcomes in terms of extent of resection and FN function. In particular, long-term FN result is much more satisfactory than short-term function. In majority of cases microsurgery represents the treatment of choice of cystic vestibular schwannomas.