Auditory Brainstem Implants for Acquired Hearing Loss: Surgical Technique and First Results

Objective: Description of surgical anatomy, typical implantation technique and preliminary clinical results in the first two patients implanted with auditory brainstem implants (ABIs) in our hospital via a retrosigmoidal route after resection of acoustic neuromas.

Methods: Retrospective case series. Main outcome variable is the acquisition of useful auditory impression after a minimal follow-up of six months. Factors possibly influencing a successful implantation are critically analyzed.

Results: Over 2 years two patients were implanted with a Synchrony Pin ABI (MedEl, Innsbruck, Austria). Patient JL, 22f, suffers from neurofibromatosis type II and psychomotor retardation. She is deaf after bilateral extirpation of acoustic neuromas. The ABI was implanted during resection of a small recurrent neuroma. Patient RT, 37m, suffers from neurofibromatosis type II and bilateral deafness after resection of acoustic neuromas. The ABI was implanted three months after tumor resection during facialis anastomosis. No technical problems and no complications were observed. One year after implantation, JL is able to register surrounding noises and to complete spoken words in a “closed set.” Her psychomotor retardation limits the training. RT reached a similar level after three months. We expect him to be able to follow free speech. Dysesthesias in the left hemisoma limited unrestricted training.

Conclusion: Both patients benefit from the ABI in daily life. A successful implantation depends on (1) the close observation of anatomical and technical nuances, (2) on the ability of the patient to actively interact with speech therapists during post-implantation fine-tuning, and (3) on the lack of relevant side effects.