Intralabyrinthine schwannomas : Surgical management and hearing rehabilitation with cochlear implants. German version

Abstract

Intralabyrinthine schwannomas (ILS) are arare differential diagnosis of sudden hearing loss and vertigo. In an own case series of 12patients, 6tumors showed an intracochlear, 3 an intravestibular, 1atransmodiolar including the cerebello-pontine angle (CPA), 1atransotic including the CPA and 1amultilocular location. The tumors were removed surgically in 9patients, whereas 3patients opted for a"wait-and-test-and-scan" strategy. Of the surgical patients, 3underwent labyrinthectomy and cochlear implant (CI) surgery in asingle stage procedure; 1patient received extended cochleostomy with CI surgery; 3underwent partial or subtotal cochleoectomy, with partial cochlear reconstruction and CI surgery (n= 1) or implantation of electrode dummies for possible later CI following repeated MRI follow-up (n= 2); and in 2patients, the tumors of the internal auditory canal and cerebellopontile angle exhibiting transmodiolar or transmacular growth were removed by combined translabyrinthine-transotic resection. For the intracochlear tumors, vestibular function could mostly be preserved after surgery. In all cases with CI surgery, hearing rehabilitation was successful, although speech discrimination was limited for the case with subtotal cochleoectomy. Surgical removal of intracochlear schwannomas via partial or subtotal cochleoectomy is, in principle, possible with preservation of vestibular function. In the authors' opinion, radiotherapy of ILS is only indicated in isolated cases. Provided performed early enough, cochlear implantation after surgical removal of ILS is an option for auditory rehabilitation, thus representing-in contrast to the "wait-and-test-and-scan" strategy-a therapeutic approach.