Expanded Transcanal Transpromontorial Approach: A Novel Surgical Technique for Cerebellopontine Angle Vestibular Schwannoma Removal

Objective: Vestibular schwannoma (VS) is a benign tumor of the lateral skull base. Different microscopic surgical techniques are described in literature: the retrosigmoid and translabyrinthine approaches are used to treat big tumors located in the cerebellopontine angle, and the middle cranial fossa approach is utilized for small tumors with good hearing preservation. The expanded transcanal transpromontorial (ExpTT) approach is a combined microscopic-endoscopic technique previously indicated for Koos stage I and II VS and now proposed for larger VS, up to 3 cm in diameter, with linear progression into the cerebellopontine angle and touching the brainstem. Study Design: The study was a retrospective case series of patients who underwent ExpTT surgery for VS in our ear, nose, and throat department. Setting: We reviewed the surgical videos and electrophysiologic data recorded during the surgical operations. Subjects and Methods: From January 2015 to January 2017, 20 patients affected by Koos stage II and III VS underwent surgery in our department with the ExpTT approach. This novel technique is described step by step, with a focus on the surgical procedure and anatomic landmarks; outcomes are detailed in terms of early and late complications. The mean follow-up was 15 months. Results: The ExpTT approach permitted, in all patients, gross total resection of the tumor without any complication and with preservation of facial nerve function. All patients had a good postoperative recovery. Conclusion: The ExpTT technique is a new approach that combines the advantages of a microscopic technique with the ones offered by the endoscope in removal of VS.