Comparison between Retrosigmoid and Translabyrinthine Approaches for Large Vestibular Schwannoma: Focus on Cerebellar Retraction Injury

Objective: Both retrosigmoid (RS) and translabyrinthine (TL) approaches are primary strategies to resect large vestibular schwannoma (VS), but direct comparison between both approaches has seldom been reported. This study aimed to compare surgical outcomes and morbidities of both approaches, with a focus on cerebellar retraction injury.

Methods: Seventy-four consecutive patients with large VS undergoing the RS or TL approach were reviewed between August 2010 and January 2018. Surgical and functional outcomes, operating time, volume change of cerebellar edema, and inpatient rehabilitation after postoperative care were compared between the two approaches.

Results: In total, 48 and 24 patients underwent RS and TL approaches with a median follow-up period of 43 and 13 months, respectively. Except for the follow-up period, all preoperative characteristics did not statistically differ between both groups. Surgical and functional outcomes including the extent of resection, tumor recurrence, complications, and facial nerve preservation were not shown significant difference between both groups. However, the median change in volume between pre- and postoperative cerebellar edema, presumably caused by retraction injury, was significantly larger in the RS group than in the TL group (6.6 vs. 0.7 cm³, p <  0.001) and was related to the RS approach selection (p = 0.001), solid VS (p = 0.007), and the main operation time (p = 0.001). In the RS group, cerebellar damage increased with increased time for tumor resection. However, cerebellar injury did not depend on the time for tumor removal in the TL group. Moreover, patients in the RS group showed a marginal trend for receiving inpatient rehabilitation because of cerebellar dysfunction and/or lower cranial nerve deficits (p = 0.052).

Conclusion: Both surgical approaches show equivalent tumor control and facial nerve preservation. Notably, the TL approach for large VS has advantages in reduction of cerebellar retraction injury and early recovery from cerebellar morbidities. Though the TL approach is hearing-destructive, this approach may be a reasonable surgical option in selected patients with large VS.

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