The peculiar cystic vestibular schwannoma: a single-center experience.

OBJECTIVE: The operative management of cystic vestibular schwannoma is more challenging. In this study, we focus on the peculiarity of cystic vestibular schwannoma in terms of management and outcome. We evaluated a homogenous series of consecutive patients with cystic vestibular schwannomas who were operated on with a similar technique and via the same surgical approach.
METHODS: The patients with vestibular schwannoma who were operated at our center from 2000 to 2012 were retrospectively analyzed. Those having cystic vestibular schwannomas, recognized by the presence of cystic components both on the preoperative magnetic resonance imaging and intraoperatively, were included. Thirty-seven consecutive patients matched the inclusive criteria. The whole pool of solid vestibular schwannomas with similar tumor extension was used as a control group. The facial nerve outcome is reported early after surgery and after 1-year follow-up. Facial nerve palsy GI-III according to House-Brackmann grading system was considered a favorable outcome. Facial nerve palsy GIV-VI was considered unfavorable. The surgical morbidity in the 2 groups was compared. A special point of interest was the correlation between the cyst pattern and outcome.
RESULTS: Cystic vestibular schwannomas are associated with a worse early facial nerve outcome (unfavorable in 37.8% in cystic vestibular schwannoma compared with 17.5% in the solid variant). After 1-year follow-up, 8.1% of the cystic variant had unfavorable facial nerve outcome. Meanwhile, 6.2% of the solid variant had unfavorable outcomes. There was no statistically significant difference between both groups regarding the long-term facial nerve outcome. The cystic variant had a greater postoperative morbidity rates, especially hemorrhage (8.1%), in comparison with solid vestibular schwannoma of the same extension (1.7%). Hydrocephalus without significant hematoma is also significantly greater in the cystic type than the solid variant. Medially located thin walled cysts are related to worse facial nerve outcome.
CONCLUSION: Surgery of cystic vestibular schwannomas is associated with a greater rate of morbidity and facial nerve dysfunction compared with the solid variant. Special attention is required during facial dissection to allow functional preservation, especially with tumors with medially located thin walled cysts. Meticulous hemostasis also is required to avoid postoperative hematoma. Close postoperative care is mandatory for early detection and prompt management of possible postoperative complications.