Simultaneous cochlear implantation during retrosigmoid resection of a large vestibular schwannoma under continuous electrically evoked auditory brainstem response monitoring.

We report, through close collaboration between neurosurgery and otolaryngology, what is, to our knowledge, the first case of simultaneous CI during retrosigmoid resection of a large sporadic vestibular schwannomas under continuous intraoperative electrically evoked auditory brainstem response (evoked auditory brainstem response) monitoring.

A 70-year-old woman with a 30-mm Koos grade 4 sporadic vestibular schwannomas and contralateral profound hearing loss presented with right-sided scale-out audiometry (bilateral speech discrimination 0%).

Resection was terminated when wave V amplitude reached approximately 20% of baseline, achieving subtotal removal with preserved facial nerve function.