Endoscopic far-lateral supracerebellar infratentorial approach for resection of dumbbell-shaped trigeminal schwannoma: Surgical techniques and preliminary results

Background: Trigeminal schwannomas (TSs) are mostly benign tumors and the dumbbell-shaped subtype is the most challenging, surgery remains difficult and risky. Objective: We introduce a novel surgical approach named endoscopic far-lateral infratentorial supracerebellar approach (EFL-SCITA) for removing dumbbell-shaped TSs, and further discuss our experience and operation technique. Methods: EF-SCITA was performed for resection of 5 cases of TSs between January 2020 and April 2022. The entire procedure was done endoscopically with the goal of total tumor resection. During the operation, the tumor was exposed in close proximity and multiple angles under the endoscope, and the peri-tumor nerves were carefully identified and protected, especially the normal trigeminal fiber bundles around the tumor. Results: All the tumors of 5 cases involved the middle and posterior cranial fossa, of which total removal was achieved in 2 cases, near-total removal in 2 cases and subtotal removal in 1 case. Most common preoperative symptoms improved after surgery. Two patients had postoperative mild facial paralysis (House-Brackmann grade II), 1 patient had abducens palsy, both recovered during the follow-up period. Two patients experienced new postoperative facial hypesthesia and 1 experienced mastication weakness, which were not recovered. There was no tumor recurrence or residual tumor growth during the follow-up period in any of the patients. Conclusion: EFL-SCITA is a new and effective alternative for the surgical treatment of TSs. For dumbbell-shaped TSs, this approach provides sufficient surgical field exposure and freedom of operation.