Treatment Failure Following Stereotactic Radiosurgery for Vestibular Schwannomas: Surgery or Repeat Stereotactic Radiosurgery?

Objective: We report a series of patients who underwent surgery for treatment failure following SRS. We also compare the results of surgery with reported literature on repeat SRS. Patients and Methods: A retrospective review identified 21 patients [median age: 49 years (range: 23–84 years)] who underwent surgical excision between 2000 and 2015 following treatment failure with GK-SRS. Five patients had NF2. The median interval from radiotherapy to surgery was 37 months (range: 4–228 months). The median size of tumor at surgery was 3 cm (range: 2–5 cm). 8 (38%) had total macroscopic excision, 9 (43%) near total and 4 (19%) subtotal excision. Results: Of the 17 patients with preoperative HB grade 1 facial function, 53% of patients had HB grade 1–2 postoperatively. During the follow-up period 2 patients, both with NF2 (1 subtotal and 1 near-total tumor excision) had enlarging residuum. 2 patients with NF2 and subtotal excision had stable residuum. There was no evidence of tumor recurrence in patients who had complete tumor excision (including 1 patient with NF2). All non-NF2 patients with subtotal and near total tumor excision had a stable residuum. The literature on repeat SRS is limited with a range of clinical practice and short follow-up. Conclusion: Surgery for VS following treatment failure with SRS provides good tumor growth control rates but with higher rates of poor facial nerve outcome. The surgery can be technically challenging. Repeat SRS provides good short-term tumor growth control and low rates of facial nerve morbidity in selected patients; however, the long-term data are limited.