Individualized evaluation of vestibular schwannoma and strategy of interal auditory canal management via retrosigmoid approach

Abstract

Objective To investigate the strategy of internal auditory canal (IAC) management in retrosigmoid approach for vestibular schwannoma after accurate implementation of preoperative individualized assessment. Methods The clinical data of 149 patients with vestibular schwannoma who underwent resection via retrosigmoid approach at The First Affiliated Hospital of Chongqing Medical University were retrospectively analyzed from January 2018 to January 2022. The tumors in IAC were conventionally treated by drilling open the posterior wall of the IAC in 95 patients (the drilling open IAC group), and treated by scraping method in 54 patients (the scraping group). Tumor resection rate and postoperative complication rate were recorded, and facial nerve function was evaluated by House⁃Brackmann (H⁃B) grade at 6 months after surgery. Results In the patients who were treated with drilling open the posterior wall of the IAC, gross total resection (GTR) was performed in 37 cases (38.95%), near total resection (NTR) in 30 cases (31.58%), subtotal resection (STR) and majority resection in 28 cases (29.47%). Forty⁃seven cases (49.47%) of H⁃B grade Ⅰ-Ⅱ, 22 cases (23.16%) of Ⅲ and 23 cases (24.21%) of Ⅳ-Ⅵ were classified at 6 months after surgery. Incidence of complications: cerebrospinal fluid (CBF) leakage in 5 cases (5.26%), intracranial infection in 9 cases (9.47%), pulmonary infection in 13 cases (13.68%), and intermuscular venous thrombosis in 6 cases (6.32%). In patients who were treated with scraping method, GTR was performed in 12 cases (22.22%), NTR in 22 cases (40.74%), while STR and majority resection in 20 cases (37.04%). Twenty⁃one cases (38.89%) of H⁃B grade Ⅰ-Ⅱ, 16 cases (29.63%) of Ⅲ and 17 cases (31.48%) of Ⅳ-Ⅵ were classified at 6 months after the surgery. Incidence of complications: CSF leakage in 0 cases, intracranial infection in 4 cases (7.41%), pulmonary infection in 7 cases (12.96%), and intermuscular venous thrombosis in 3 cases (5.56%). Tumor resection rate (χ2=0.902, P=0.342), facial nerve function at 6 months after surgery (χ2=0.282, P=0.594), intracranial infection (χ2=0.185, P=0.667), pulmonary infection (χ2=0.015, P=0.901) and lower limb intermuscular venous thrombosis (χ2=0.035, P=0.851) were not statistically significant in 2 groups. Conclusions Conventionally drilling open the posterior wall of the IAC is the preferred method to deal with the IAC, and scraping can be used as a selective supplement after strict preoperative evaluation.

Keywords

• neuroma
• acoustic
• cerebellopontine angle
• ear
• inner
• microsurgery