Abordagem Translabiríntica para Ressecção de Schwannoma Vestibular de Grau IV de Koos com Preservação Anatômica e Funcional do Nervo Facial: Vídeo Cirúrgico

Abstract

Introduction: Vestibular schwannomas are benign tumors of the cerebellopontine angle whose surgical management is particularly challenging in large lesions because of their proximity to the facial nerve, brainstem, and other critical neurovascular structures. In patients with non-serviceable hearing, the translabyrinthine approach provides direct access to the internal auditory canal (IAC) and cerebellopontine angle, enables early facial nerve identification, and minimizes cerebellar retraction. Case Report: A 56-year-old woman presented with a large left-sided Koos grade IV vestibular schwannoma associated with non-serviceable hearing. Microsurgical resection was performed through a standard translabyrinthine approach under continuous facial nerve monitoring. After mastoidectomy and labyrinthectomy, the IAC was completely skeletonized, allowing early identification of the facial nerve and direct exposure of the intracanalicular tumor component. Progressive internal debulking reduced tumor volume and facilitated extracapsular microsurgical dissection from the surrounding neurovascular structures. Complete tumor removal was achieved with preservation of the anatomical continuity and intraoperative functional integrity of the facial nerve. Skull base reconstruction focused on prevention of cerebrospinal fluid leakage. The Eustachian tube was meticulously obliterated using autologous muscle and fibrin sealant. The Trautmann triangle defect and mastoid cavity were reconstructed with temporalis fascia, fibrin glue, abdominal fat graft, and titanium mesh cranioplasty, creating a multilayer closure. Results: The patient developed immediate postoperative House–Brackmann grade V facial palsy. Despite the severe early deficit, progressive neurological recovery occurred, and facial nerve function returned to House–Brackmann grade I within 60 days, confirming successful functional preservation of the nerve. Conclusion: The translabyrinthine approach is a very good option for large vestibular schwannomas in patients without useful hearing. It provides wide exposure of the IAC and cerebellopontine angle, facilitates early facial nerve identification, and virtually eliminates the need for cerebellar retraction. This case demonstrates that complete resection of a Koos grade IV vestibular schwannoma can be achieved with favorable long-term facial nerve outcome, even after severe immediate postoperative paresis. Meticulous multilayer skull base reconstruction is essential to minimize the risk of postoperative cerebrospinal fluid leakage.