Clinical Characteristics of Microsurgical Removal for Vestibular Schwannoma after Gamma Knife Radiosurgery

Background: The aim of the study was to evaluate the clinical characteristics of microsurgical removal for vestibular schwannoma (VS) after failed gamma knife radiosurgery (GKS).

Method: We surgically treated five female patients who had previously undergone GKS. The patients' ages ranged from 37 to 51 years (mean, 44.2 years). The retrospective analysis included tumor control rate, pre- and postoperative House-Brackmann grades, postoperative complications, operative findings, and difficulties during microsurgery.

Results: Microsurgery involved the translabyrinthine/transcochlear approach in all patients. Tumor expansion involved cystic enlargement in one patient, solid in three, and central necrosis in one. Adhesion to the brainstem was severe in three patients. Anatomical preservation of the facial nerve was done in five operations. Dissection of the tumor from the facial nerve was difficult in most interventions because of severe adhesions or color change. The tumor was subtotally removed in three patients. The function of the facial nerve deteriorated in three patients and was unchanged in two patients.

Conclusions: After GKS, delaying the follow-up period will result in a variety of surgical difficulties. The proper timing for surgery might be missed. Therefore, we recommend that patients who require microsurgery after GKS be treated immediately rather than taking time for observation.