Influencing analysis of hearing preservation after retrosigmoid approach surgery for vestibular schwannoma

Objective To investigate the influencing factors of hearing preservation after retrosigmoid approach surgery for vestibular schwannoma. Methods A total of 317 patients with vestibular schwannoma treated by retrosigmoid approach surgery in Beijing Tiantan Hospital from January 2018 to January 2021 were included. Tumor size (Koos grade), whether the tumor invaded the bottom of the internal auditory canal, and whether the tumor had cystic changes were evaluated by preoperative imaging examination. Hearing function was evaluated by the American Academy of Otolaryngology⁃Head and Neck Surgery (AAO⁃HNS) hearing classification before and after surgery. Univariate and multivariate forward Logistic regression analysis were used to investigate the related risk factors of hearing loss after retrosigmoid approach surgery. Results Among 317 patients, 35 cases (11.04%) had postoperative hearing preservation (AAO⁃HNS A and B) and all of them had normal preoperative hearing. The rates of age＞45 years old (χ2=45.648, P=0.000), Koos grade 3-4 (χ2=41.692, P=0.000), invasion the bottom of internal auditory canal (χ2=30.252, P=0.000), cystic changes (χ2=23.888, P=0.000) and preoperative hearing abnormality (χ2=78.317, P=0.000) in hearing loss group were higher than those in hearing preservation group. Logistic regression analysis showed the age＞45 years old (OR=36.211, 95%CI: 5.006-261.918; P=0.000), Koosgrade 3-4 (OR=21.215, 95%CI: 2.867-156.963; P=0.003), invasion the bottom of internal auditory canal (OR=13.746, 95%CI: 3.005-62.880; P=0.001) and cystic changes in tumor (OR=8.336, 95%CI: 1.943-35.770; P=0.004) were the risk factors of hearing loss after retrosigmoid approach surgery. Conclusions Retrosigmoid approach surgery is a safe and effective surgical approach for patients with vestibular schwannoma to achieve hearing preservation. Younger patients, with smaller tumors, and without invasion the bottom of internal auditory canal and without cystic changes in tumors are more likely to have postoperative hearing preservation.