Extended Retrolabyrinthine Approach: Results of Hearing Preservation Surgery Using a New System for Continuous Near Real-time Neuromonitoring in Patients With Growing Vestibular Schwannomas

OBJECTIVE: To report hearing preservation results after retrolabyrinthine vestibular schwannoma surgery, using a new system for continuous near real-time monitoring of cochlear nerve function.

STUDY DESIGN: Retrospective chart review.

SETTING: Tertiary referral center, University Hospital.

PATIENTS: Thirty-one consecutive patients with growing vestibular schwannomas and opting for hearing preservation surgery.

INTERVENTIONS: Tumor removal by a modified, extended retrolabyrinthine approach, using a new system for continuous near real-time monitoring of cochlear nerve function.

MAIN OUTCOME MEASURES: Pure-tone average and speech discrimination (SD) 1-year postoperative. Preservation of word recognition score class. Preservation of serviceable hearing (SD>50%).

RESULTS: Any hearing was preserved in 83 and 69% had preserved word recognition score class or better. Serviceable hearing was preserved in 77%. SD was unchanged in 48%, improved in 21%, and poorer in 31%. Of 18 patients with potential for improvement (SD 90% or worse preoperatively), 33% improved (SD increase 10% or more).

CONCLUSION: The hearing preservation rate is favorable using the modified, extended retrolabyrinthine approach and a new system for continuous near real-time monitoring of cochlear nerve function for removal of growing vestibular schwannomas, as 77% preserved serviceable hearing 1 year after surgery. Hearing improved after surgery in 33%. Using the new neuromonitoring system, serviceable hearing preservation rate improved from 53 to 77% at our center.