Vestibular schwannoma after cochlear implantation

Content The occurrence rate of vestibular schwannomas is described as 1 per 100.000/y. With at present about 500.000 cochlear implantees the probability of newly occurring vestibular schwannoma after cochlear implantation is low, but not negligible. Usually an MRI is performed as part of the regular preoperativ evaluation setup to exclude this kind of tumor.

The MRI slice thickness though is not standardized for this indication. Accordingly, there is, besides the occurrence of new vestibular schwannoma after cochlear implantation, a limited probability of undetected small schwannomas before cochlear implantation. Even mosaic cases of NFII can be present.

Case report: We are presenting the case of a cochlear implantee with the detection of an ipsilateral vestibular schwannoma two years after initial cochlear implantation.

At the beginning the patient suffered from unilateral deafness and a vestibular schwannoma on the contralateral side. First the cochlear implantation was performed on the deaf-side. The cochlear implantee presented a regular performance after implantation. Pre-OP-MRI slice thickness was 2 mm. Afterwards a schwannoma resection was performed. MRI scanning was performed as part of the tumor follow up, in which the ipsilateral vestibular schwannoma was detected. The patient was classified, based on the radiological pattern, as a case of mosaic NFII. There was no suspicion on NFII beforehand.

Conclusion Vestibular Schwannoma after cochlear implantation may newly occur or can be undetected, related to a too thick MRI slice thickness preoperatively. MRI is an important tool in investigating unclear performance losses after cochlear implantation. Taking a possible need for a postoperative MRI into account, implant positioning and magnet configuration is of high importance.

Poster-PDF A-1638.pdf

Publication History

Article published online:
13 May 2021