Individual surgical management of trigeminal schwannomas guided by an extended classification: a consecutive series of 96 clinical cases at a single institution

Trigeminal schwannoma (TS) is a rare intracranial neurinoma that affects the multicompartmental skull base. In recent decades, advancements in skull-base neurosurgical techniques and endoscopic surgery have significantly improved outcomes for TS patients. In this study, we present our experience with surgical resection of TS using a further classification system. We conducted a retrospective analysis of the clinical, surgical, and follow-up data of 96 patients diagnosed with TS at our institution between March 2012 and June 2022. The tumors were classified based on the MPE classification, with Type M further divided into M1 and M2 subtypes according to the origin of the tumor and the patterns of cavernous sinus (CS) invasion. Type MP tumors were divided into M1P and M2P subtypes based on whether the tumors in the middle cranial fossa extended into the anterior CS. Optimal surgical approaches were proposed for each subtype. The outcomes of the case series were collected and analyzed. Based on the further MPE classification, 32 tumors were classified as Type M2P, 21 as Type M1P, 12 as Type ME, 8 as Type P, 8 as Type M1, 8 as Type MPE, and 7 as Type M2. Gross total resection (GTR) was achieved in 88 patients, while five patients underwent subtotal resection (STR), and three patients received partial resection (PR). No deaths occurred during the perioperative period. The extended MPE classification provides specific insights into the features of TS involving the middle fossa, enabling more individualized and tailored treatment strategies, as well as appropriate approach selection. The combination of microsurgery, endoscopic surgery, and stereotactic radiotherapy can lead to satisfactory outcomes in managing complex TS, achieving high rates of GTR while minimizing complications.