gms | German Medical Science

Objective: Surgical results of large or giant tumor and cystic vestibular schwannoma (LCV) are reported to be unfavorable when compared to those of small and solid tumors (LSV). In retrospect we analyzed the extent of removal, operation time and facial nerve outcome of LCV comparing with LSV.

Methods: From 2000 to 2011, 178 vestibular schwannomas were removed by the senior author using a retrosigmoid approach. Among these, the number of large or giant tumors with a maximum diameter of over 30 mm at the CP angle was 71 (40%). The tumor was defined as an LCV when more than 50% of the tumor was cystic. Under sophisticated facial nerve monitoring, complete tumor removal was intended in all cases. A small piece may be left, however, if a severe adhesion to the facial nerve was found and monitoring showed poor response during dissection. Facial nerve function was evaluated with House-Brackmann facial nerve grade (HB) at the follow-up. Results were statistically analyzed.

Results: Thirty tumors (42%) were LCV and 41 (58%) were LSV in large tumors.n The mean maximum diameter at the CP angle was 39.8 mm for LCV and 36.4 mm for LSV (NS). Mean duration of surgery was 6:27 hours ranging from 3:47 to 9:44 hours for LCV and 8:05 hours ranging from 4:30 to 11:50 hours for LSV(p < 0.05). Complete tumor removal could be achieved in 18 (60%) of LCV and 26 (63.4%) of LSV (NS). Nearly total removal was achieved in the rest of cases. Good facial nerve function (HB 1 or 2) was obtained in 26 (86.7%) LCV and 37 (90.2%) LSV (NS).

Conclusions: Large or giant cystic vestibular schwannoma can be removed with favorable results based on the policy that nearly total removal is accepted in selected adherent cases. Careful dissection, sophisticated monitoring and decision making during surgery are important to achieve good outcome in large or giant cystic vestibular schwannoma surgery.