Endoscopic-Assisted Supraorbital Retroinfundibular Approach to the Interpeduncular Fossa: A Cadaveric Operability Study

Background: Surgical approaches to the retroinfundibular area (mainly anterosuperior and lateral parts of the anterior incisural space) are challenging; recently, few reports have described endoscopic-assisted approaches to this area.

Objective: The purpose of this study is to investigate and evaluate the exposure and operability of these areas provided by an endoscopic-assisted supraorbital approach through the infrachiasmatic window and optical-carotid triangle. We also tested a simulated clipping procedure to assess the surgical maneuverability.

Materials and Methods: Six alcohol-immersed cadaveric heads injected with pigmented silicone rubber were prepared for bilateral dissections. After a standard 3 × 1.5-cm craniotomy was performed at the supraorbital forehead, we advanced the dissection through the following steps: (1) creating the intradural subfrontal corridor, (2) performing the endoscopic anterior clinoidectomy, (3) mobilizing the clinoid segment of internal carotid artery, and (4) drilling the tuberculum sellae. Two angled (0 and 30°) rigid endoscopes with outer diameters of 4 mm (Aesculap, Pennsylvania, USA) were introduced. We compared the exposure and surgical maneuverability of the approach using the microscopic mode alone with the endoscopic-assisted mode. We used an evaluation scale to assess exposure and operability that was developed by our laboratory.

Results: We evaluated the exposure and the surgical maneuverability of key anatomical structures of the retroinfundibular area. The structures evaluated included the diaphragma sellae, the dorsum sellae, the posterior clinoid process, the pituitary stalk, the mammillary bodies, the tuber cinereum, the oculomotor nerves, the basal pons, the upper trunk of the basilar artery, the superior cerebellar arteries, the posterior cerebral arteries, the posterior communicating arteries, and the basilar bifurcation. The exposure and the surgical maneuverability were significantly higher in the endoscopic-assisted mode (P = 0.03).

Conclusion: Based on our study, the endoscopic-assisted supraorbital retroinfundibular approach is associated with better performance than the pure microscopic approach. Further clinical information is required to verify the value in practice.