Long-Term Outcomes of Subtotal Resection for Large Vestibular Schwannomas: Results From the Acoustic Neuroma Subtotal Resection Study—Part III Perioperative Measures and Complications

BACKGROUND AND OBJECTIVES: Management of large vestibular schwannomas (VS) increasingly includes partial resection strategies, yet the impact of extent of resection on perioperative and long-term symptom outcomes remains unclear. This study evaluates how the extent of resection influences perioperative measures, complications, and balance performance. METHODS: A prospective, multicenter cohort study was conducted from 2004 to 2019. A total of 126 patients with VS measuring at least 2.5 cm were enrolled. Perioperative outcomes included operation duration, length of stay, and complications such as cerebrospinal fluid leak, wound infection, and meningitis. Long-term outcomes included headache severity, Dizziness Handicap Inventory scores, and standardized balance testing. Analyses accounted for demographic variables, tumor characteristics, and surgical approach. RESULTS: The mean patient age was 48 ± 14 years, and the mean cerebellopontine angle tumor diameter was 3.3 ± 0.7 cm. Based on postoperative MRI, 35 patients underwent gross total resection, 39 underwent near-total resection, and 52 underwent subtotal resection (STR). Operation duration, length of stay, and overall complication rates did not differ by extent of resection. Younger age was associated with cerebrospinal fluid leak (P = .024), and meningitis was more frequent after translabyrinthine approach (P = .03). At 1 year, patients who underwent gross total resection or near-total resection exhibited significant improvement in headache severity (P = .015 and P = .012), whereas STR patients did not. Residual tumor volume showed a significant positive association with Dizziness Handicap Inventory score at 1 year (r = 0.55, P = .03). STR was also associated with poorer postoperative balance performance. CONCLUSION: The extent of resection did not influence perioperative measures or early complication rates in large VS surgery. However, subtotal resection was associated with persistent headaches, greater dizziness handicap, and worse balance outcomes at 1 year. These findings indicate that partial resection does not confer perioperative benefit and may compromise long-term symptom recovery compared with more complete resection.