Transmeatal microsurgery for intralabyrinthine and intrameatal schwannomas: a reappraisal

OBJECTIVE: The interest in surgical routes to the internal auditory canal (IAC) through the external auditory canal for vestibular schwannoma removal has been recently raised by the endoscopic approaches to the lateral skull base. The aim of the study was to reappraise the transmeatal microsurgical approach (TMMa) to the labyrinth and IAC, first described 50 years ago. METHODS: A retrospective series of 8 consecutive patients treated for intralabyrinthine and intrameatal schwannomas through TMMa is presented. Main outcome measures consisted of surgical indications, postoperative complications, facial nerve status, bed mobilisation time, hospitalisation time and tumour recurrence rate. RESULTS: Surgical indications for TMMa were tumour growth (62.5%) and disabling vertigo (37.5%) in the present series. Complete tumour removal with no complications and postoperative normal facial nerve function was obtained in all cases. Bed mobilisation occurred after a median of 3 postoperative days (IQR 2.2-3.0) and discharge after a median of 5.6 days (IQR 4.7-7.0). After a median follow-up of 13 months (IQR 7.5-27.5), no tumour recurrence was observed. CONCLUSIONS: TMMa indications are limited to schwannomas of the labyrinth and IAC, which dropped out from observation protocols due to unmanageable symptoms or growth. Despite the narrow mini-invasive surgical corridor, the TMMa was a safe an effective microsurgical technique in terms of tumour removal and postoperative course.