Tractography-Based Prediction of Trigeminal Nerve Displacement Patterns in Cavernous Sinus and Meckel's Cave Tumors: Correlation With Intraoperative Findings.

BACKGROUND AND OBJECTIVES: Tumors involving the cavernous sinus (CS) and Meckel's cave, such as trigeminal schwannomas and meningiomas, frequently displace the trigeminal nerve. This study aimed to classify displacement patterns of the trigeminal nerve using diffusion tensor imaging (DTI) tractography and evaluate its predictive accuracy compared with intraoperative findings. METHODS: We retrospectively reviewed 28 patients who underwent resection of CS- or Meckel's cave-involving tumors. Preoperative DTI tractography was compared with intraoperative nerve positioning. The correlation between displacement patterns and the selection of surgical approaches (lateral approach such as transcranial or transorbital, and medial approach like endonasal) was analyzed. RESULTS: Preoperative DTI tractography accurately predicted the trigeminal nerve position in 26 of 28 patients, yielding a concordance rate of 92.9%. Identified displacement patterns included medial (n = 7), lateral (n = 13), and encased (n = 8) configurations. In cases of medial displacement, a lateral approach was performed in all cases (100%), achieving an 85.7% favorable outcome rate. For lateral displacement, a medial approach (n = 4) resulted in a 100% favorable outcome rate, whereas a lateral approach (n = 9) yielded a 66.7% favorable outcome rate. All cases with an encased pattern (n = 8) were managed through a lateral approach, with a 25% favorable outcome rate observed. Although nerve displacement guided surgical planning, a lateral approach was often preferred to facilitate the technical manipulation of firm tumors. CONCLUSION: Preoperative DTI tractography is a reliable tool for predicting trigeminal nerve displacement. While displacement patterns guide the surgical route, the histological nature of the tumor, specifically the need for easier manipulation in firm tumors, often dictates a preference for lateral approaches over medial ones to ensure safer resection. DTI tractography should be regarded as a decision support tool that complements intraoperative assessment and microsurgical judgment in achieving maximal safe resection.