Surgical management of transmodiolar, transmacular, and multilocular vestibular and cochlear schwannomas with or without hearing rehabilitation with cochlear implants

Intralabyrinthine schwannomas (ILS) can present in the cochlea or in the posterior labyrinth, with transmodiolar or transmacular growth into the internal auditory canal (IAC) with or without extension into the cerebello-pontine angle (CPA) or, very rarely, multilocular.

In an own case series of 44 patients with ILS, the tumors were found also transmodiolar (6 pts. including 2 with CPA), transmacular (1 pt.), translabyrinthine (1 pt.), multilocular (2 pts.), and transotic (1 pt.). In all 11 patients the tumors were completely or - depending on the goal of the treatment (i.e. hearing rehabilitation) - partially resected through a partial or subtotal cochleoectomy (+/- labyrinthectomy), a combined translabyrinthine-transotic approach, a single-stage translabyrinthine approach or a two-stage suboccipital approach with later partial cochleoectomy. Nine patients received a cochlear implant.

In cases, where hearing rehabilitation was the goal, it was necessary to leave tumor remnants behind (e.g. in the modiolus and in the fundus of the IAC) in order to preserve the cochlear nerve fibers. Despite that, the majority of patients reached surprisingly good speech understanding with the cochlear implant with up to 90 % monosyllables in quiet at 65 dB SPL.

Cochlear implantation appears to be an option for auditory rehabilitation even in cases of transmodiolar/transmacular or ipsilateral-multilocular tumors of the eighth nerve. In view of functional rehabilitation, it resembles an alternative approach to complete tumor removal with the destruction of the nerve fibers or a „wait-and-test-and-scan-strategy“.

Poster-PDF A-1996.PDF

Publication History

Article published online:
10 June 2020