Modified Exclusive Endoscopic Transcanal Transpromontorial Approach for Vestibular Schwannomas

Objective We evaluated the feasibility of a modified exclusive endoscopic transcanal transpromontorial approach (EETTA) for the treatment of small vestibular Schwannomas (VSs) limited to the internal auditory canal (IAC) and we introduced its modification without external auditory canal closure.

Methods Between January 2015 and May 2016, five patients underwent tumor removal via translabyrinthine microsurgery (TLA group), and from June to September 2016, seven patients underwent surgery via a modified EETTA (EETTA group) for VS confined to the IAC. The treatment outcomes were compared between two groups in terms of the efficacy of tumor resection, preservation of function, operation time, and quality of life.

Results The patients preoperatively exhibited Koos Grade I or II tumors and a hearing status of American Academy of Otolaryngology-Head and Neck Surgery class D. Postoperative magnetic resonance imaging findings confirmed gross total resections in all cases. There were no major complications, such as cerebrospinal fluid leakage or hemorrhage. All patients exhibited normal facial nerve function immediately after surgery, and the Short Form-36 scores for quality of life were similar in most domains in both groups (p = 0.013 and 0.031, respectively). The operation time in the modified EETTA group (210.6 ± 85.3 minutes) was much shorter than that in the TLA group (351.6 ± 51.8 minutes; p = 0.008). In addition, the duration of hospitalization was also shorter in the modified EETTA group (7.4 ± 1.0 days) than in the TLA group (9.0 ± 0.7 days; p = 0.012). The mean follow-up periods were 9 and 20 months, respectively.

Conclusion The modified EETTA was effective for the removal of VSs in the IAC. It requires a less invasive procedure than do conventional microscopic approaches, with a shorter operation time.

No conflict of interest has been declared by the author(s).