Neurofibromatosis 2: hearing restoration options.

UNLABELLED: Neurofibromatosis 2 (NF2) is an autosomal dominant disease in which hearing loss is predominant. Auditory restoration is possible using cochlear implants (CI) or auditory brainstem implant (ABI). OBJECTIVE: To assess the auditory results of CI and ABI in NF2 patients and review the literature. METHODS: Four NF2 patients were prospectively evaluated. They were submitted to tumor resection followed by ipsilateral CI or ABI depending on cochlear nerve preservation. Long term auditory results were described for CI (12 months) and ABI (48 months). RESULTS: All patients achieved auditory perception improvements in their hearing thresholds. The CI patient does not recognize vowels or sentences. The 3 ABI patients discriminate 70% of vowels and 86% in the 4-choice test. One of them does not recognize sentences. The other two recognize 100% of closed sentences and 10% and 20% of open sentences. CONCLUSION: The choice of implant type to restore hearing to NF2 patients will relay on anatomical and functional cochlear nerve preservation during tumor resection surgery. Although our experience was different, the literature shows that if this condition is achieved, CI will offer better auditory results. If not, ABI is recommended.

Neurofibromatose 2: opções de restauração auditiva / Neurofibromatosis 2: hearing restoration options

Neurofibromatose 2 (NF2) é uma doença autossômica dominante que, invariavelmente, cursa com surdez. Restauração auditiva pode ser realizada por meio do implante coclear (IC) ou implante auditivo de tronco encefálico (ABI). OBJETIVO: Avaliar resultados auditivos de IC e ABI em pacientes com NF2 e revisão de literatura. MÉTODO: Foram avaliados prospectivamente quatro pacientes com NF2 submetidos à exérese tumoral e implantação de IC ou ABI ipsilateral simultâneo, dependendo se o nervo coclear foi preservado ou não cirurgicamente. São descritos resultados auditivos em longo prazo (12-48 meses). RESULTADOS: Todos pacientes implantados obtiveram percepção sonora, com melhora dos limiares tonais. A paciente com IC não discrimina vogais nem sentenças. Os três pacientes com ABI apresentam discriminação média de vogais de 70% e teste 4-choice 86%. Um paciente não discrimina sentenças. Os outros dois discriminam 100% de sentenças em formato fechado e em formato aberto 10% e 20%. CONCLUSÃO: A escolha do tipo de implante usado na restauração auditiva de portadores NF2 dependerá da preservação anatômica e funcional do nervo coclear na cirurgia de ressecção tumoral. Embora nossa experiência mostre o contrário, a literatura mostra que, se essa condição for alcançada, IC fornecerá melhores resultados auditivos. Caso contrário, ABI trará maiores benefícios.

Neurofibromatosis 2 (NF2) is an autosomal dominant disease in which hearing loss is predominant. Auditory restoration is possible using cochlear implants (CI) or auditory brainstem implant (ABI). OBJECTIVE: To assess the auditory results of CI and ABI in NF2 patients and review the literature. METHODS: Four NF2 patients were prospectively evaluated. They were submitted to tumor resection followed by ipsilateral CI or ABI depending on cochlear nerve preservation. Long term auditory results were described for CI (12 months) and ABI (48 months). RESULTS: All patients achieved auditory perception improvements in their hearing thresholds. The CI patient does not recognize vowels or sentences. The 3 ABI patients discriminate 70% of vowels and 86% in the 4-choice test. One of them does not recognize sentences. The other two recognize 100% of closed sentences and 10% and 20% of open sentences. CONCLUSION: The choice of implant type to restore hearing to NF2 patients will relay on anatomical and functional cochlear nerve preservation during tumor resection surgery. Although our experience was different, the literature shows that if this condition is achieved, CI will offer better auditory results. If not, ABI is recommended.

Auditory Brainstem Implant: surgical technique and early audiological results in patients with neurofibromatosis type 2.

UNLABELLED: Auditory Brainstem Implants were developed to partially restore the hearing capabilities of patients without cochlear nerves bilaterally. AIM: this paper aims to discuss the clinical and surgical findings of four ABI patients. MATERIALS AND METHOD: Four patients diagnosed with bilateral schwannomas received auditory brainstem implants (ABI) and had one of their tumors resected in the same surgical procedure. Clinical aspects, surgical technique, anatomic landmarks, and outcomes were analyzed. RESULTS: the anatomic landmarks were identified in all four patients in relation to the foramina of Luschka. Two patients had CSF leaks. The electrodes were well positioned and hearing sensation was good enough to allow for sound recognition and assist patients perform lip reading. CONCLUSION: the outcomes observed in our patients were quite encouraging and offer great perspectives for those suffering from deep bilateral deafness and impaired central auditory pathways.

Implante auditivo de tronco cerebral: técnica cirúrgica e resultados auditivos precoces em pacientes com neurofibromatose tipo 2 / Auditory Brainstem Implant: surgical technique and early audiological results in patients with neurofibromatosis type 2

O implante auditivo de tronco cerebral foi desenvolvido para restaurar alguma audição útil em pacientes que apresentam ausência de nervo coclear bilateralmente. OBJETIVOS: Discutir a indicação, cirurgia e resultados em quatro pacientes submetidos à cirurgia para colocação de implante auditivo de tronco cerebral. CASUÍSTICA E MÉTODOS: Quatro pacientes com diagnóstico de schwannomas vestibulares bilaterais foram submetidos à cirurgia para colocação de Implante Auditivo de Tronco Cerebral durante o mesmo ato cirúrgico utilizado para a exérese de um dos tumores. Aspectos clínicos e técnicos e as referências anatômicas da cirurgia e os resultados auditivos foram analisados. RESULTADOS: Em todos os casos foram identificados as referências anatômicas ao forame de Luschka. As complicações cirúrgicas se resumiram à fístula liquórica em dois pacientes. Os eletrodos foram bem posicionados e a sensação auditiva foi suficiente para reconhecimento de sons e auxílio à leitura labial. CONCLUSÃO: Os resultados auditivos de nossos pacientes abrem uma perspectiva importante aos pacientes com surdez profunda bilateral sem integridade anatômica das vias auditivas centrais.

Auditory Brainstem Implants were developed to partially restore the hearing capabilities of patients without cochlear nerves bilaterally. AIM: this paper aims to discuss the clinical and surgical findings of four ABI patients. MATERIALS AND METHOD: four patients diagnosed with bilateral schwannomas received auditory brainstem implants (ABI) and had one of their tumors resected in the same surgical procedure. Clinical aspects, surgical technique, anatomic landmarks, and outcomes were analyzed. RESULTS: the anatomic landmarks were identified in all four patients in relation to the foramina of Luschka. Two patients had CSF leaks. The electrodes were well positioned and hearing sensation was good enough to allow for sound recognition and assist patients perform lip reading. CONCLUSION: the outcomes observed in our patients were quite encouraging and offer great perspectives for those suffering from deep bilateral deafness and impaired central auditory pathways.