Microsurgical Resection: The State-of-the-Art Strategy for Hearing Preservation in Small Vestibular Schwannomas: Surgical Video.

Introduction: Microsurgical resection through the retrosigmoid approach remains a standard treatment option for intracanalicular vestibular schwannomas, particularly in young patients with serviceable hearing. In selected cases, surgery provides immediate tumor removal and long-term tumor control while offering the possibility of preserving hearing and facial nerve function. Meticulous microsurgical technique and continuous intraoperative neurophysiological monitoring are essential to optimize functional outcomes. Case Report: An 18-year-old woman presented with a right-sided Koos grade I intracanalicular vestibular schwannoma and preserved serviceable hearing. Gross-total tumor resection was performed through a retrosigmoid approach with the patient in the park-bench position. After dural opening, cerebrospinal fluid was released to obtain cerebellar relaxation and minimize the need for cerebellar retraction. The internal auditory canal was widely drilled to expose the intracanalicular tumor. Microsurgical dissection was performed under high magnification with continuous neurophysiological monitoring, including auditory brainstem responses (ABRs), facial motor evoked potentials (MEPs), and direct facial nerve stimulation. Particular attention was given to preservation of the arachnoid planes, cochlear nerve, facial nerve, and vascular supply to the auditory structures. Careful tumor mobilization and progressive dissection allowed gross-total removal with anatomical and functional preservation of both the cochlear and facial nerves. Postoperatively, the patient maintained serviceable hearing and normal facial nerve function, corresponding to House–Brackmann grade I, without new neurological deficits. Results: Long-term magnetic resonance imaging follow-up demonstrated no evidence of residual or recurrent tumor. The patient continues to maintain serviceable hearing and normal facial nerve function, confirming a durable favorable outcome. Conclusion: Microsurgical resection through the retrosigmoid approach is an excellent definitive treatment option for selected young patients with small intracanalicular vestibular schwannomas and preserved hearing. Adequate exposure of the internal auditory canal, meticulous microsurgical dissection, preservation of neural and vascular structures, and multimodal neurophysiological monitoring can allow gross-total tumor removal while maintaining hearing and facial nerve function. In appropriately selected patients, this strategy provides durable tumor control and long-term functional preservation without leaving a residual lesion requiring continued surveillance.