Resseção Microcirúrgica Transmastóide de um Tumor do Saco Endolinfático Através do Triângulo de Trautmann: Vídeo Cirúrgico

Abstract

Introduction: Endolymphatic sac tumors (ELSTs) are rare, locally aggressive papillary neoplasms arising from the endolymphatic sac and duct. Although histologically benign, they may behave aggressively due to progressive bone erosion and invasion of adjacent neurovascular structures. Patients commonly present with progressive hearing loss, tinnitus, vertigo, and vestibular dysfunction, significantly affecting quality of life. Complete microsurgical resection remains the treatment of choice for symptomatic tumors, providing excellent long-term control when total removal is achieved. We present the surgical management of an endolymphatic sac tumor through a transmastoid approach, emphasizing anatomical landmarks and microsurgical principles. Case Report: A 40-year-old man presented with progressive left-sided pulsatile tinnitus, hearing loss, episodic vertigo, and aural fullness, causing significant functional impairment. Computed tomography revealed irregular erosive destruction of the retrolabyrinthine temporal bone, a characteristic finding of ELST. Magnetic resonance imaging demonstrated an intensely enhancing lesion centered on the left endolymphatic sac, located along the posterior surface of the petrous bone and adjacent to the posterior semicircular canal and sigmoid sinus. Microsurgical resection was performed through a transmastoid approach. After complete mastoidectomy, the sigmoid sinus, posterior semicircular canal, and Trautmann’s triangle were widely exposed, providing access to the posterior petrous region. Careful drilling and anatomical identification of surrounding structures allowed controlled tumor exposure while preserving the labyrinth and neurovascular anatomy. The posterior fossa dura within Trautmann’s triangle was opened, enabling direct visualization and complete microsurgical resection under high magnification. Tumor dissection was performed with meticulous attention to its relationship with the sigmoid sinus, posterior semicircular canal, and facial nerve. Continuous unimodal intraoperative facial nerve monitoring was used throughout the procedure, allowing functional assessment and preservation of facial nerve integrity. Gross-total tumor removal was achieved without injury to surrounding neurovascular structures. The operative field was carefully inspected to confirm complete resection and adequate hemostasis. Results: The postoperative course was uneventful, with complete resolution of pulsatile tinnitus and preservation of facial nerve function. The patient remained neurologically intact during long-term follow-up. After 12 years of clinical and radiological surveillance, there was no evidence of tumor recurrence, and the patient remained asymptomatic with preserved neurological function. Conclusion: The transmastoid approach provides a direct and effective surgical corridor for selected endolymphatic sac tumors. Wide exposure of Trautmann’s triangle allows safe access to the posterior petrous region, facilitating complete microsurgical resection while minimizing morbidity. This case demonstrates that tailored skull base surgery can provide durable tumor control and excellent long-term functional outcomes when complete removal is anatomically feasible.