Endoscope-Assisted Retromastoid Intradural Suprameatal Approach for Trigeminal Schwannoma.

[BACKGROUND AND INTRODUCTION] Dumbbell trigeminal schwannoma is the second most common type of intracranial schwannomas.

[OBJECTIVE] Herein, we are describing and presenting a video of left trigeminal dumbbell schwannoma with a predominant posterior fossa component (modified Samii's grade C1), operated through left Retromastoid Intradural Suprameatal Approach (RISA). We demonstrate a step by step technique of a previously defined procedure for educational purpose.

[SURGICAL TECHNIQUE] The patient was placed in the right lateral position, and left retromastoid craniotomy was done. Dura was opened based on transverse and sigmoid sinus to expose tumors in the suprameatal region. The tumor removed piecemeal under the microscope, and later endoscope was introduced to identify and remove the residual tumor in the superolateral part of Meckel's cave.

[RESULTS] The patient had an uneventful recovery.

[CONCLUSION] Trigeminal schwannoma with a predominantly posterior fossa component can be excised through retromastoid sub-occipital craniotomy. Endoscopic-assisted microsurgery should be considered in all skull base tumors. Aim for complete excision, but safe maximal resection with GKRS for residual can be considered in difficult cases.