Facial nerve function after vestibular schwannoma surgery following failed conservative management.

Background: Because only a limited proportion of vestibular schwannomas display growth after diagnosis, an increasing number of patients are managed conservatively. Tumor growth during "wait and scan" may, however, necessitate surgery. In these cases, increased tumor size is likely to increase the risk of impaired facial nerve function after surgery.

Objective: To compare facial nerve function in patients operated on soon after diagnosis with patients allocated to conservative management and the subgroup of these who later had surgery because of tumor growth.

Methods: A total of 1378 consecutive patients diagnosed with a vestibular schwannoma 20 mm extrameatal or smaller were included; 419 patients were operated on soon after diagnosis, and 959 patients were initially managed conservatively. In the latter group, 161 patients were subsequently operated on owing to tumor growth.

Results: All conservatively managed patients had normal facial nerve function at the end of observation. Good facial nerve outcome was found in 87% of patients operated on at diagnosis and in 84% of patients operated on after established tumor growth. For the subgroup of small extrameatal tumors, this difference was significant. When all patients allocated primarily to conservative management were pooled, good facial function was found in 97%, which was significantly better than the result for primary operation (87%).

Conclusion: Overall, conservative management of small to medium-sized vestibular schwannomas is the best option in terms of preservation of facial nerve function. Tumor growth during observation is found in only a minor proportion of the patients, and in these cases, surgery or irradiation should be performed immediately.