Contralateral Hearing Loss after Vestibular Schwannoma Resection

Introduction: Vestibular schwannoma is the most frequent tumor of the cerebellopontine angle. Microsurgical resection is associated with intraoperative cerebrospinal fluid loss and can be complicated by postoperative cerebrospinal fluid (CSF) leak. A rare but documented complication of vestibular schwannoma resection is postoperative hearing loss in the contralateral ear. In most cases, this is a transient hearing loss. We describe a patient who had a severe sensorineural hearing loss in the contralateral ear following translabyrinthine resection of a vestibular schwannoma in whom hearing was successfully rehabilitated with a cochlear implant.

Case Presentation: A 57-year-old female was referred with the diagnosis of a left vestibular schwannoma. She had a baseline bilateral hearing loss secondary to the measles virus at 9 months of age, but her hearing loss had worsened in the left ear over the preceding few years, leading to her diagnosis of a vestibular schwannoma. She also had new-onset left-sided tinnitus. Her initial audiogram revealed a mild-to-severe sensorineural hearing loss in the right ear and moderately severe to severe sensorineural hearing loss in the left ear. Her word recognition was 92% on the right and 0% on the left. Imaging showed an enhancing left internal auditory canal and cerebellopontine angle mass measuring 2.6 cm × 2.5 cm × 3.1 cm. She underwent a left translabyrinthine craniotomy for removal, at which point tumor remnant was left on the brainstem and facial nerve due to adherence in these locations. Her 6-month postoperative MRI showed significant regrowth of the tumor, with the tumor remnant almost doubling in size. Revision surgery was recommended, and she underwent a revision translabyrinthine craniotomy with subtotal tumor resection. About 12 hours postoperatively, the patient reported a significant decrease in her hearing in the right ear. Intravenous steroid therapy was initiated, and an audiogram was obtained. Her audiogram showed a profound sensorineural hearing loss with 0% word recognition in the right ear. On postoperative day 2, a postoperative CSF leak manifested with clear rhinorrhea, and she underwent a left subtotal petrosectomy with blind sac closure of the left external auditory canal. She was followed with serial audiograms. She recovered some puretone thresholds and word recognition in the right ear, but her sound quality and perceived benefit from a right hearing aid were poor. She underwent a right cochlear implant 6 weeks after her revision translabyrinthine craniotomy and received excellent benefit from her cochlear implant.

Discussion: The mechanism of contralateral hearing loss after vestibular schwannoma resection is unclear, and hearing recovery is variable. One proposed mechanism is a relative endolymphatic hydrops after the normal intraoperative loss of CSF. In this patient, her postoperative CSF leak could also have been a contributing factor to her hearing loss. At current, there is no consensus on management and treatment of this postoperative event. Further investigation into the incidence and etiology of contralateral postoperative hearing loss after vestibular schwannoma surgery is warranted. We advocate for early traditional amplification and, when indicated, cochlear implantation for optimal hearing rehabilitation.

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Artikel online veröffentlicht:
12. Februar 2021