Surgical Management of Vestibular Schwannomas after Failed Radiation

Background: Increasingly, patients with vestibular schwannoma (VS) are being treated with stereotactic radiation therapy (SRT). Some of these patients do not respond to radiation and will need secondary surgery. It is important for skull base surgeons to become familiar with the unique challenges posed by this disease entity.

Objective: To document difficulties and discuss surgical strategies in a select group of patients who failed SRT for VS.

Methods: A consecutive series of 55 patients with VS who failed SRT were surgically treated. Radiation-related symptoms, tumor growth at follow-up, intraoperative findings, and operative results were evaluated.

Results: There were 15 males and 40 females patients with a mean age of 48.7 years. Thirty-two patients had been treated by SRT only (R-VS), and 23 patients had a combination of microsurgical tumor debulking and SRT (MR-VS). Forty-four patients (80%) demonstrated steady tumor growth after SRT, and six patients (10.1%) had a rapid tumor growth after several years of quiescence. Side effects of SRT in this series were deafness (50%), facial numbness (30.8%), facial nerve palsy (15.4%), facial pain (15.4%), and increased vertigo or tinnitus. Intraoperative findings demonstrated fibrous tumors, cyst formation, and yellow or purple discoloration of tumor capsule. Severe adhesions between the tumor capsule, cranial nerves, vessels, and brainstem were observed in 68.8% of the R-VS group. Gross total resection (GTR) was achieved in 41.8%. Six patients (14.6%) newly developed facial nerve palsy postoperatively.

Conclusion: Our findings suggest that patients with VS who fail SRT with either tumor progression or worsening of clinical symptoms will have an increased rate of adhesions to the neurovascular structures. Salvage surgery for these tumors will have a higher risk of postoperative complications.