Learning Objectives:
Intraoperative monitoring of the facial nerve and the cochlear nerve is essential to achieve preservation of function after surgery to vestibular schwannomas. Recently two novel monitoring methods have been reported to improve preservation of function: continuous direct auditory evoked dorsal cochlear nucleus action potential (AEDNAP) monitoring and facial nerve root exit zone-elicited compound muscle action potential (FREMAP) monitoring (Nakatomi and Miyazaki, et al. 2015). A presigmoid retrolabyrinthine approach is considered to have the advantages of the two major approaches, the retrosigmoid suboccipital and presigmoid translabyrinthine approaches, as a minimally invasive surgical option to vestibular schwannomas, allowing direct access to the cerebellopontine angle and preservation of hearing function (Iacoangeli et al. 2013). Here, we report a case of presigmoid retrolabyrinthine approach to medium vestibular schwannoma by use of continuous monitoring of the facial nerve and the cochlear nerve, as a novel surgical method to achieve a minimally invasive surgery with preservation of function.