The extracisternal approach in vestibular schwannoma surgery and facial nerve preservation

Abstract

The classical surgical technique for the resection of vestibular schwannomas (VS) has emphasized the microsurgical anatomy of cranial nerves. We believe that the focus on preservation of the arachnoid membrane may serve as a safe guide for tumor removal. Method: The extracisternal approach is described in detail. We reviewed charts from 120 patients treated with this technique between 2006 and 2012. Surgical results were evaluated based on the extension of resection, tumor relapse, and facial nerve function. Results: Overall gross total resection was achieved in 81% of the patients. The overall postoperative facial nerve function House-Brackmann grades I-II at one year was 93%. There was no recurrence in 4.2 years mean follow up. Conclusion: The extracisternal technique differs from other surgical descriptions on the treatment of VS by not requiring the identification of the facial nerve, as long as we preserve the arachnoid envelope in the total circumference of the tumor.Keywords: arachnoid membrane, facial nerve, surgery, vestibular schwannoma, acoustic neurinoma. RESUMOA técnica cirúrgica clássica para ressecção de schwannomas vestibulares enfatiza a anatomia microcirúrgica dos nervos cranianos. Acreditamos que o foco na preservação da membrana aracnóide pode servir como parâmetro seguro para a remoção do tumor. Método: A abordagem extracisternal é descrita em detalhe. Analisamos o prontuário de 120 pacientes tratados com esta técnica entre 2006 e 2012. Os resultados cirúrgicos foram baseados em extensão de ressecção, recorrência tumoral e função do nervo facial. Resultados: Ressecção total foi obtida em 81% dos pacientes. O resultado global da função do nervo facial (House-Brackmann graus I-II) após um ano da cirurgia foi de 93%. Não houve recidiva em um seguimento médio de 4,2 anos. Conclusão: A técnica extracisternal difere de outras descrições cirúrgicas no tratamento de schwannoma vestibular pois não requer a identificação do nervo facial, contanto que o plano de aracnóide seja preservado em toda circunferência do tumor.Palavras-chave: membrana aracnóide, nervo facial, cirurgia, schwannoma vestibular, neurinoma do acústico.Facial nerve injury is a common complication in the treatment of vestibular schwannomas (VS) and its associated facial muscle palsy has a great impact in patients' quality of life 1 . This is the reason why functional preservation of the facial nerve is sought when managing VS with either radiosurgery or microsurgery. Several factors have been correlated with worse facial nerve function outcomes, including older patients, large tumors, and preoperative facial nerve function 2,3,4 . Although careful facial nerve dissection is pursued, anatomical preservation of the facial nerve is not synonymous of normal function 5,6,7 . Intraoperative monitoring of the facial nerve is the key for optimal facial nerve preservation, even though not all patients' clinical courses correlate with their intraoperative electrophysiological result 6,8 . The classical descriptions of the surgical tech...

Application of Subperineural Resection Technique in Vestibular Schwannomas: Surgical Efficacy and Outcomes in 124 patients

“…Therefore, when the interface between the tumor and the perineurium could not be separated using the microdissector, neurosurgeons must use a microscissor to perform sharp dissection in order to create an interface at the mixed level of nerve fibers and tumor cells. In this way, although a small part of the tumor tissue may remain on the perineurium above nerves, the possibility of preserving the function of the facial–auditory nerve will be significantly improved ( 11 , 24 , 25 ).…”