Acoustic neuroma (vestibular schwannoma): surgical results on 240 patients operated on dorsal decubitus position

Abstract

-Objective: To evaluate the result of the surgical treatment of vestibular schwannoma (VS) operated in dorsal decubitus (mastoid position). Method: 240 patients with a VS underwent a retrosigmoid craniotomy for tumor resection in dorsal decubitus (mastoid position). The function of 7 th and 8 th cranial nerves was monitored during surgery and the opened internal auditory canal (IAC) was reconstructed using a vascularized dura flap, muscle and fibrin glue. Results: Complete tumor removal was achieved in 99% of the cases, with a mortality of 1.6%. The facial nerve function was preserved in 85% of cases and hearing in 40% of the patients (with preoperative hearing) with tumors of up 1.5 cm in diameter. The incidence of cerebrospinal fluid leak was 5.8% and meningitis 2.9%. Venous air embolism was registered in 3% of cases; it was not associated to mortality. Conclusion: Surgical removal of VS in dorsal position has several advantages; the morbidity and mortality are very low.KEY WORDS: acoustic neuroma, vestibular schwannoma, mastoid position, venous air embolism.Neurinoma do acústico (schwannoma do vestibular): resultados do tratamento cirúrgico de 240 pacientes operados na posição de decúbito dorsal RESUMO -Objetivo: Avaliar o resultado do tratamento cirúrgico de pacientes portadores de schwannoma do vestibular (SV) operados em decúbito dorsal (posição de mastóide). Método: 240 pacientes foram submetidos a craniotomia retrosigmóide na posição de mastóide. A função do VII e VIII nervos cranianos foi monitorizada durante a cirurgia e a reconstrução da abertura do conduto auditivo interno foi realizada com retalho vascularizado de dura-mater, músculo e cola de fibrina. Resultados: A exérese foi completa em 99% dos casos, com mortalidade de 1,6%. Houve preservação da função do nervo facial em 85% dos casos e da audição em 40% dos pacientes com audição prévia e tumores menores de 1,5 cm. A incidência de fístula liquórica foi 5,8% e meningite 2,9%. Embolia gasosa foi registrada em 3% dos casos, não associada à mortalidade. Conclusão: O tratamento cirúrgico dos SV utilizando-se a posição de mastóide tem várias vantagens, com baixa morbidade e mortalidade. PALAVRAS-CHAVE: neurinoma do acústico, schwannoma vestibular, posição de mastóide, embolia gasosa.

Post-operative complications after removal of sporadic vestibular schwannoma via retrosigmoid-suboccipital approach: current diagnosis and management

“…Nonetheless, according to other authors [20] the risk of facial palsy after vestibular schwannoma surgery is the lowest among all available surgical approaches when using the translabyrinthine approach. In order to assess the facial nerve function, pre-as well as post-operatively, the most commonly used tool was the House-Brackmann scale [4,7,8,13,16,17,21]. Facial electromyography (EMG) has also been a useful tool, because it facilitates the surgical procedure and plays an important role in the prevention of facial paresis.…”

“…There was, therefore, minimal bleeding in the surgical field but the danger of venous air embolism was high, due to the gradient of venous pressure between the surgical site and the heart. This is why recent studies suggest the dorsal decubitus position which still has the risk of venous air embolism, but at a much lower rate (3%) [7]. In the event of a venous air embolism, the diagnosis can be confirmed using Doppler ultrasonic air bubble detection and can be treated with aspiration through an inserted right atrial catheter [52].…”

“…As a next step, lumbar drainage along with compressive dressing [1,7] is recommended, which has been successful in most cases. In patients with incisional leak a simple wound re-stitching usually suffices.…”

An Unusual Variant of Cerebellopontine Angle Schwannoma in a Young Nepalese Girl

“…Middle fossa approach is primarily for those tumors which are limited to the internal auditory canal and preserves hearing functions. Limited access to CPA and temporal lobe retraction are two main disadvantages of this approach [13]. Mortality and morbidity have been reduced grossly in the recent years.…”

Surgical exposure of the internal auditory canal through the retrosigmoid approach with semicircular canals anatomical preservation

“…Preservation of hearing is possible using this approach. Some authors (mainly ENT surgeons) claim as drawback of this approach the impossibility of complete exposure of the fundus of the IAC without damaging the semicircular canals 4,17,18,19 . Injury of the labyrinth structures during posterior IAC wall drilling may cause deafness even with preservation of cochlear nerve.…”