Auditory Brainstem Implantation in Neurofibromatosis Type 2: Experience From the Manchester Programme.

OBJECTIVE: To describe the experience of auditory brainstem implantation (ABI) in patients with Neurofibromatosis type 2 (NF2). STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral centre. PATIENTS: Implanted with a Cochlear ABI22 or ABI24M between 1994 and 2009 because of NF2 disease. INTERVENTION(S): Rehabilitative. MAIN OUTCOME MEASURE(S): Surgical complication rate; audiological outcomes. RESULTS: There were 50 primary ABI insertions in 49 patients, including 16 inserted at the time of first side tumor removal as a sleeper, and two revision repositionings which failed to improve outcome. Postoperatively three patients had cerebrospinal fluid leaks which did not require reoperation, one patient had meningitis, and eleven patients suffered either temporary or permanent lower cranial nerve dysfunction. Twenty-nine patients became full time users; a further 12 patients became non-users. Three patients died while their device was inactive. Five patients retain serviceable contralateral hearing. Audiological open set testing of users showed means of: environmental sounds discrimination 51%; phoneme discrimination: with ABI alone 22%/lip reading (LR) 45%/ABI with LR 65%; sentence testing: with ABI alone 13%/LR 19%/ABI with LR 54%. CONCLUSIONS: The majority of patients with NF2 implanted with an ABI find the device a useful aid to communication in conjunction with LR and in recognizing common environmental sounds. A small proportion gain open set discrimination. Almost a third of patients may end up as non-users. There is probably an increased risk of postoperative lower cranial nerve dysfunction so careful preoperative assessment is advised.

Subjective outcomes of auditory brainstem implantation.

AIM: To assess the long-term subjective benefits of auditory brainstem implants (ABIs) and investigate the extent to which ABI users perceive it to be a useful device. METHODS: Using the Manchester database, all 31 living patients registered as ABI users were identified and sent the ABI performance questionnaire. Data regarding daily duration of use, auditory fatigue, ability to differentiate between speech and environmental sounds, and subjective usefulness of the ABI in different listening conditions were collected. Patients were asked to rate the usefulness of the device in various settings on a scale of 1 (not useful) to 6 (very useful). The mean age at implantation was 33 years (13-73 yr), and the mean follow-up period was 6 years (1.5-15 yr). RESULTS: Between March 1994 and September 2009, 57 patients underwent ABI insertion. A total of 26 patients were not eligible for inclusion in the study (19 nonusers, 5 deceased, and 2 sleepers). Of the 31 eligible patients identified as ABI users, 23 returned the questionnaire, 1 was excluded as the questionnaire had been completed on his or her behalf, giving a net response rate of 71%. Mean duration of usage per day was 12.62 hours (range, 8-16 h). Seventy-one percent of the patients turned the processor off at one or more points during the day. Differentiation between speech and environment was achieved in 95%, and 70% were able to differentiate between gender and adult and pediatric voices. The ABI was perceived as most beneficial when dealing with a familiar voice in a quiet place, with a median usefulness score of 4, rising to 5 when used in conjunction with lip reading. The ABI was least useful when dealing with an unfamiliar voice in a loud place, with a mean score of 1, rising to 2 when used in conjunction with lip reading. In all environments, combining the ABI with lip reading served to increase usefulness ratings by at least 1 point. CONCLUSION: This study demonstrates that ABI users make use of their device for at least 12 hours per day on average and obtain considerable subjective benefit in speech discrimination when using the device with familiar speakers in a quiet environment. Benefit is less significant in noise and with an unfamiliar speaker. Lip reading enhances subjective benefit by at least 1 point, and lip reading training may have a role to play in maximizing subjective benefit.

Clinical and radiological guidance in managing facial nerve schwannomas.

OBJECTIVE: To present a review of all patients diagnosed with a facial nerve schwannoma (FNS) managed in our center over almost two decades, and suggest guidelines for their classification and management. STUDY DESIGN: Retrospective case review SETTING: Tertiary referral center PATIENTS: Twenty-eight patients with a facial nerve schwannoma INTERVENTION: Conservative or surgical management depending on clinical and radiological features MAIN OUTCOME MEASURE: Patient demographics, site of tumor, and clinical symptoms, including facial nerve function (House-Brackmann score) at baseline and follow-up. In those managed surgically, operative approach and surgical outcomes were also recorded. RESULTS: Of 28 patients, 16 were male. Mean age at presentation was 46 years. The majority presented with either facial weakness or hearing loss. The internal auditory canal segment of the facial nerve was the most commonly affected (19/28, 68%). Multi-segmental lesions were found in almost half (46%) of patients. Facial weakness was most commonly associated with involvement of the labyrinthine segment (89%). Overall, 16 (57%) patients were managed surgically. CONCLUSION: FNS may be difficult to distinguish on both clinical and imaging grounds from other cerebellopontine pathologies on the basis of audiovestibular symptoms alone. The presence of facial weakness in combination with imaging findings suggestive of FNS is highly suggestive for FNS. In patients with brainstem compression, rapid tumor growth, or House-Brackmann greater than 4, we suggest a surgical approach based on preoperative audiovestibular status, helping optimize long-term facial function and minimize morbidity. Facial nerve reanimation at the time of primary surgery is preferred.

Outcomes of cochlear reimplantation in adults.

OBJECTIVE: To determine the indications for, and auditory outcomes following, cochlear reimplantation in adults and investigate factors influencing outcome. STUDY DESIGN: Retrospective case series. SETTING: Cochlear implant program in a tertiary care hospital. PATIENTS: Thirty adults (32 ears) who have undergone cochlear reimplantation in the ipsilateral ear. INTERVENTION(S): Explantation and reimplantation of cochlear implant. MAIN OUTCOME MEASURE(S): Speech discrimination as measured using Bamford-Kowal Bench sentence testing in quiet (BKBq) and noisy (BKBn) environments. RESULTS: Best BKBq improved from 58.5% to 71.4% (p = 0.0242), and BKBn improved from 60.9% to 67.2% (p = 0.826) after reimplantation. Device failure was the most common indication for reimplantation. There was no significant difference in failure rate or outcome between implant manufacturers. The mean time to reimplantation was 4.7 years, and this was not related to auditory outcome. Otosclerosis and Ménière's disease may predispose to a worse auditory outcome after reimplantation. CONCLUSION: Cochlear reimplantation does not have a detrimental effect on auditory outcomes and in some cases results in improved speech perception.

Ipsilateral cochlear implantation after cochlear nerve preserving vestibular schwannoma surgery in patients with neurofibromatosis type 2.

OBJECTIVE: To investigate the outcomes from ipsilateral simultaneous or sequential cochlear implantation in patients with neurofibromatosis type 2 (NF2) after vestibular schwannoma removal with cochlear nerve preservation. STUDY DESIGN: Retrospective case series. SETTING: Single tertiary referral NF2 center. PATIENTS: Six patients with NF2. INTERVENTION: Removal of vestibular schwannoma (VS) with preservation of the cochlear nerve and cochlear implantation. Four patients had their surgery via a translabyrinthine approach. Two patients had a retrosigmoid approach. A cochlear implant was inserted at the same time as tumor removal in 4 cases and sequentially in 2 cases. MAIN OUTCOME MEASURES: Surgical and audiometric outcomes using Bamford-Kowal-Bench (BKB) and City of New York University (CUNY) sentence scores. RESULTS: The average age at implantation was 24 years (range, 15-36 yr). Follow-up ranged from 5 to 93 months, with an average of 38 months. All patients had useful hearing in the contralateral ear before surgery. One patient gained no benefit from cochlear implantation and proceeded to have an auditory brainstem implant. Of those that had functional cochlear nerves, the average BKB score in quiet was 64%, BKB score in noise was 42%, and CUNY score with lipreading was 97%. Results varied within the group, but all patients gained significant benefit and continue to use their CI at least intermittantly. CONCLUSION: The present series demonstrates that in selected cases, cochlear implantation can be successful after a translabyrinthine approach for VS removal and for restoring hearing after failed retrosigmoid hearing preservation surgery. All patients found the cochlear implant offered useful hearing even in the presence of contralateral hearing.