title: Retrosigmoid Craniotomy for Auditory Brainstem Implantation in Adult Patients with Neurofibromatosis Type 2.
abstract: Objective To report our technique and experience using a retrosigmoid craniotomy approach for auditory brainstem implantation (ABI) placement in adult neurofibromatosis type 2 (NF2) patients. Design Retrospective case series. Setting Single-center study, Boston, Massachusetts, United States. Participants All NF2 patients who underwent evaluation at Massachusetts Eye and Ear Infirmary and surgery at Massachusetts General Hospital from 2009 to 2013 were reviewed. Six cases of retrosigmoid craniotomy for ABI surgery in five adult NF2 patients were identified. The clinical history, operative course, and outcomes in these patients were reviewed. Main Outcome Measures Postoperative complications and audiological outcomes. Results Indications for ABI surgery were profound hearing loss associated with growth or treatment of bilateral vestibular schwannomas. In all cases, a retrosigmoid craniotomy was performed for tumor resection and ABI placement without complication. Electrode placement was confirmed intraoperatively using electrical-evoked auditory brainstem responses. The ABI was activated in the awake patient 4 to 6 weeks postoperatively. Audiological testing was used to evaluate sound detection and speech perception with the ABI. There were no cases of cerebrospinal fluid leak. Conclusion Retrosigmoid craniotomy is a safe and effective means to provide access to the cochlear nucleus for ABI placement following tumor resection in the adult NF2 patient. Preliminary data indicate that this approach has few complications while offering benefits for hearing. The retrosigmoid craniotomy should be considered a reasonable alternative to the traditional translabyrinthine approach for placement of the ABI in deaf patients who are not candidates for the cochlear implant.
authors.affiliation: Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, United States; Department of Otology and Laryngology, Harvard Medical School, Boston, Massachusetts, United States.
authors.forename: Sidharth V
authors.initials: SV
authors.lastname: Puram
authors.affiliation: Department of Otology and Laryngology, Harvard Medical School, Boston, Massachusetts, United States; Department of Audiology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, United States.
authors.forename: Barbara
authors.initials: B
authors.lastname: Herrmann
authors.affiliation: Neurosurgical Service, Massachusetts General Hospital, Boston, Massachusetts, United States; Department of Surgery (Neurosurgery), Harvard Medical School, Boston, Massachusetts, United States.
authors.forename: Fred G
authors.initials: FG
authors.lastname: Barker
authors.affiliation: Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, United States; Department of Otology and Laryngology, Harvard Medical School, Boston, Massachusetts, United States.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Lee
keywords: auditory brainstem implant (ABI); neurofibromatosis type 2 (NF2); retrosigmoid craniotomy