Morphometric analysis of the topographic-anatomical relationships between the foramen ovale and other skull base structures in the context of exoendoscopic Gasserion ganglion anatomy

Background. Radiofrequency denervation of the Gasserian ganglion (GG) is an effective method for treating trigeminal neuralgia (TN). A key aspect of this procedure is the precise positioning of the needle in the area of the foramen ovale (FO). Despite the development of modern intraoperative neuronavigation technologies, the anatomical variability of the FO can hinder precise and safe intervention. Given the relevant vascular and neural structures adjacent to the GG, inaccurate needle positioning when attempting to reach for the FO may lead to serious intra- and postoperative complications. Objective. To analyze the morphometric parameters of the FO and investigate its topographic-anatomical positioning with exoendoscopic cadaver dissection for the purpose of safe radiofrequency treatments. Material and methods. A retrospective clinical investigation was conducted patients undergoing GG radiofrequency ablation for TN. The Autodesk 3ds Max program was used to calculate the angular and linear parameters of FO, the statistical analysis was carried out using the StatTech program version 3.1.8. The laboratory investigation was conducted on a formalin-fixed cadaver head prepared with silicone-injected vessels using the Aesculap Aeos exoscope and Karl Storz endoscope. Results. Based on this imaging investigation and exoendoscopic cadaver dissection, we identified three segments for needle trajectory: facial, cranial base, and middle cranial fossa areas. Within each segment, we pinpointed the critical zones that might be at risk of damage during the insertion of the puncture needle, which may lead to serious complications. Conclusion. Morphometric analysis of the FO and understanding of its exoendoscopic topographic-anatomical relationship are the key factors for a safe and effective FO puncture in the treatment of TN.