Approaches to the Meckel’s Cave: A 360-Degree Perspective—Insights from a Cadaveric Study

Background and Objective: Approaching Meckel’s cave (MC) is surgically challenging. While open approaches can be complex and are often associated with high morbidity, endoscopic approaches have emerged in the last decade as feasible alternatives. In this context, transorbital approaches have gained paramount importance. Given the anatomical complexity of the MC and the numerous described surgical routes to approach it, there is a need for quantitative data to inform and assist in the choice of surgical approach. This study aimed to objectively quantify, using neuronavigation-based systems, the differential exposure and maneuverability of four different surgical approaches to the MC from a 360-degree perspective.

Materials and Methods: This study aimed to analyze, in five embalmed latex-injected cadaveric specimens (10 sides), the differential area of exposure (AoE), surgical freedom (SF), horizontal and vertical angles of attack (AoA), and angle of exposure (AnoE) to MC using four different surgical routes from a 360-degree perspective: the endoscopic endonasal approach “front door” (EEA), the endoscopic transorbital approach “side door” (TOA), the pretemporal approach (PT), and the retrosigmoid approach (RS). Measurements were acquired using neuronavigation. The dissection began with the EEA, followed by the TOA under visualization with rod-lens endoscopes. Then, the PT was performed, followed by the RS, using a microscope. This sequential approach was strategically performed to avoid overlapping the different surgical routes. The AoE, SF, and AoAs to the foramen ovale (FO), foramen rotundum (FR), superior orbital fissure (SOF), the central point of Meckel’s cave, and porus trigeminus (PT) were measured and compared for each approach to test for objective and statistically significant differences between the routes. Finally, the AnoE was measured for the FO and FR using the ventral approaches and for the PT using the dorsolateral approaches, employing the vectorial technique recently described by our group.

Results: The PT offered the widest AoE compared to the other approaches (p < 0.001). Among the ventral approaches, EEA and TOA showed comparable AoE. This trend was also observed for the SF. The PT demonstrated the highest vertical and horizontal AoA on the FR, while the ventral approaches were comparable. The same result was obtained for the AoA on the FO, the SOF, and the central point of MC. However, while the PT provided the highest horizontal AoA on the PT, the widest vertical AoA on this structure was achieved using an RS. Regarding the AnoE, the TOA offered the largest AnoE on the FR, the PT on the FO, and the RS on the PT.

Conclusion: The PT approach offers the widest exposure and maneuverability in most areas of MC. Nevertheless, the minimally invasive endoscopic approaches appear to provide a viable and agile route to the ventral portion of MC. Notably, the TOA seems to offer the highest AnoE on the FR, providing the best ventral exposure of the MC. This study provides objective measures that may aid in selecting the most appropriate surgical strategy based on the specific tumor and patient anatomy involving MC lesions, thereby reducing surgical morbidity and improving the extent of resection.

Publication History

Article published online:
07 February 2025