Step by step cadaveric dissection of endoscopic transorbital pretemporal approach to the temporal uncus and parapeduncular space with its clinical application

Lesions involving the temporal uncus and the parapeduncular space are surgically challenging because of their proximity to critical neurovascular structures. This study aimed to evaluate the anatomical feasibility and clinical applicability of the endoscopic transorbital pretemporal approach (ETOPTA) for safe access to this region through the lateral aspect of the oculomotor nerve (CN III). Stepwise cadaveric dissections were performed on four head specimens to assess the feasibility of the ETOPTA for accessing the temporal uncus and the parapeduncular space. Based on these anatomical findings, the clinical applicability of the ETOPTA was further demonstrated through illustrative patient cases. The ETOPTA provided a direct and minimally invasive route to the uncus, parapeduncular space, and ventrolateral pontomesencephalic junction without temporal lobe retraction or extensive Sylvian fissure dissection. Under endoscopic magnification, the major neurovascular structures around the oculomotor-tentorial triangle were clearly identified. In both illustrative cases, the ETOPTA allowed safe and effective access to the region surrounding the uncus and the parapeduncular space, achieving the intended surgical goals with preservation of critical structures. The ETOPTA enabled safe and effective access to the mesial temporal region and parapeduncular space through a short, straight, and minimally invasive route. This approach may represent a feasible alternative corridor for selected lesions involving the uncus and the ventrolateral pontomesencephalic region.