Objective: The aim of this study was to evaluate the hearing results after surgery for T1 and T2 vestibular schwannomas (VS) via the middle cranial fossa (MCF) approach at one institution and to review outcomes in the recent literature.
Patients and methods: In our department, 208 consecutive patients have undergone surgery using the MCF approach between December 2005 and February 2015. Audiological testing included pure-tone audiometry, speech-discrimination-tests pre- and postoperatively, as well as a pre- and intraoperative brainstem evoked response audiometry (BERA). Hearing status was categorized according to the American Academy of Otolaryngology - Head and Neck Surgery (AAO-HNS) or Gardner-Robertson classification. Hearing preservation was assessed when postoperative values were still within class A + B.
Results: In 167 of the 208 patients, preoperative hearing levels corresponded to class A+B. In 78 tumors, extension of the VS was limited to the internal auditory canal (T1) and in 89 tumors there was an extrameatal growth without touching the brainstem (T2). In 109 patients (65 %), postoperative hearing was still in class A+B. In the group of intrameatal tumors, the hearing preservation rate was even 69 %. The analysis of the literature of the past 16 years revealed comparable results (46-82 %).
Conclusions: Surgery for VS using the MCF approach is an established technique for reliable tumor removal with an adequate rate of hearing preservation. For small tumors without brainstem contact, particularly satisfying results can be achieved. This should be taken into account when discussing the possibility of early hearing preservation surgery.
Keywords: acoustic neuroma; early surgery; hearing preservation; middle cranial fossa approach; vestibular schwannoma.