Long-Term Hearing Preservation Outcomes for Small Vestibular Schwannomas: Retrosigmoid Removal Versus Observation

Management of small vestibular schwannomas (VSs) consists of three options: serial observation, radiosurgery, and microsurgery. The authors reported the long-term hearing outcomes after retrosigmoid tumor removal in 110 patients and hearing follow-up outcomes in 160 serial observation patients with small VSs to explore the appropriate management strategy and predictive factors of hearing preservation for small VSs.

Retrospective study.

Tertiary referral center.

In this study, 110 patients with small VS (purely intracanalicular/cerebellopontine angle tumor ≤15 mm) during a 15-year period, from January 2001 to December 2015, were candidates for hearing preservation surgery through retrosigmoid approach, while 160 patients were candidates for serial observation. The main outcome measure was preservation of hearing under different hearing levels, assessed with the classification of American Academy of Otolaryngology-Head and Neck Surgery.

Preoperative hearing levels of the 110 study patients were Class A in 49 patients, Class B in 43 patients, and Class C in 18 patients. In all surgery patients (n = 110), 97.3% (107/110) patients maintained the same level during postoperative follow-up (mean follow-up time was 49.1 ± 28.2 mo) and 86 (78.2%) had complete radiologic and audiometric data at least 4 years follow-up for review. In the 4 years follow-up surgery group (n = 86), postoperative hearing levels were Class A, B, C, and D for 22, 11, 18, and 35 patients, and postoperative rates of preservation of serviceable and useful hearing were 59.3% (51/86) and 47.1% (33/70), respectively. In serial observation group, mean follow-up time was 35.2 ± 33.1 months; mean tumor size at presentation was 8.6 ± 4.3 mm; overall mean tumor growth rate was 1.08 ± 2.3 mm/yr; serviceable hearing preservation rate of 98 patients was 54.1% (53/98) at the 5-year end point and 48.7% (37/76) at the 7-year end point.

Tumor removal should be the first treatment option for patients with small VSs and preserved hearing, especially for young patients with good hearing; retrosigmoid approach is an effective and safe approach for small VSs removal with excellent functional outcomes; better preoperative hearing predicted a higher rate of postoperative hearing preservation; patients without fundal extension were more likely to achieve hearing preservation than those with fundal extension, but no difference had been detected when retrosigmoid removal assisted with endoscope was performed; patients with small tumors originating from SVN were more likely to achieve hearing preservation compared with those with IVN-originating tumors.