Utilization of the Transotic Approach for Select Cases of Vestibular Schwannoma Resection

Background: Vestibular schwannomas (VS) with significant intracochlear extension or extension to the anterior surface of the brainstem pose a challenge to a complete surgical resection. The transotic approach allows access to these regions via removal of the entire otic capsule without facial nerve re-routing and provides a more direct view of the basilar artery, potentially decreasing the risk of neurovascular injury. Due to these advantages, we utilize the transotic approach for vestibular schwannoma which meet these select criteria.

Objective: Examine outcomes of transotic approach to resection of VS with anterior cerebellopontine angle (CPA) or cochlear extension.

Methods: Retrospective analysis of patients managed at a tertiary care academic medical center between 2009 and 2019.

Results: Nine patients underwent transotic approach to VS resection during the study period. The indications for surgery included cochlear extension from the internal auditory canal in 5 patients, intracochlear tumor on 1 patient, and anterior CPA extension in 3 patients. Two patients had continued growth after previous stereotactic radiosurgery. Mean tumor length in the largest dimension was 40 mm. Seven patients underwent gross total resection (GTR) while two underwent subtotal resections. The facial nerve was anatomically intact at the conclusion of surgery in all cases. Eight patients had good (House–Brackmann grade I or II) facial nerve function preoperatively. Of these, 5 had a similar level of function postoperatively, while 3 had poor (grade IV–VI) function postoperatively and have undergone facial reanimation procedures. Complications included cerebrospinal fluid leak in 2 patients, and sigmoid sinus thrombosis in one patient, which resolved without sequelae with chemical anticoagulation.

Conclusions: The transotic approach offers good rates of GTR in large and difficult-to-remove tumors that involve areas not accessed via more commonly used approaches, such as those with anterior CPA or intracochlear extension. In addition, the angle of approach may reduce the risk of injury to the basilar artery. The complication rate is comparable to other approaches for large VS.