Revisiting the Telovelar Approach for Lesions of the Mesial Part of the Cerebellar Peduncles by Using the Cerebellar Functional Networks to Guide Surgical Practice

BACKGROUND AND OBJECTIVES: Lesions of the cerebellar peduncles (CPs), particularly the mesial CP, pose a surgical challenge because of their deep location and the risk of disrupting critical neural pathways. Given their low incidence, the safest and most anatomically sound surgical approach for this region remains to be determined. This study analyzes the surgical anatomy and technique of the telovelar approach with particular focus on the white matter tract anatomy of the middle (MCP), inferior (ICP), and superior CPs. By integrating cadaveric studies, tractographic anatomy and surgical cases, we provide an in-depth anatomic framework that highlights white matter preservation and its implications for patient outcomes. METHODS: We analyzed the white matter fiber architecture of the CPs using 3 formalin-fixed adult human brains treated with Klinger's technique, a single formalin-fixed, color-latex-injected cadaveric head, and diffusion tensor imaging-based tractography from a healthy male volunteer. Stepwise cadaveric dissections and tractographic reconstructions were performed to delineate fiber tract trajectories relevant to the telovelar approach. In addition, 3 illustrative clinical cases were included to correlate anatomic findings with surgical considerations. RESULTS: Cadaveric white matter, cranial dissections, tractography, and intraoperative images were synthesized to provide a structured stepwise guide for the telovelar approach. The resultant distinct anatomic trajectories of MCP, ICP, and superior CP fibers, underscore the differential impact of surgical approaches on white matter integrity. Compared with the retrosigmoid approach, which risks disrupting lateral MCP fibers, the telovelar route preserves these pathways while primarily interacting with ICP fibers, potentially mitigating postoperative motor deficits. CONCLUSION: By integrating white matter fiber dissection and tractography, this study refines the anatomic basis of the telovelar approach for mesial cerebellar peduncle lesions and its impact on critical cerebellar pathways. Understanding these three-dimensional white matter relationships enhances intraoperative decision-making, optimizes surgical strategies and advances the neurosurgical field toward functionally informed, minimally disruptive interventions.