Endoscopic endonasal resection of transinfundibular craniopharyngiomas using a vertical infundibular split with subpial excavation: Case instruction and operative video.

Background: Radical resection of transinfundibular craniopharyngiomas (TCs) while preserving endocrine function remains a major surgical challenge because of their origin within the pituitary stalk. The "vertical infundibular split with subpial excavation" (VISSE) technique in endoscopic endonasal surgery (EES) is an effective approach that may enable gross total resection (GTR) in selected cases while aiming to preserve pituitary stalk integrity and neuroendocrine function. This procedure involves a vertical split of the pia mater of the pituitary stalk at sites with sparse pituitary portal veins, followed by subpial circumferential dissection along the tumor-stalk interface. Methods: We report two patients with TC who underwent EES using the VISSE technique, achieving GTR with pituitary stalk preservation. Case 1 was a 68-year-old woman with an 18-mm solid TC compressing the optic chiasm and involving the pituitary stalk. Case 2 was a 53-year-old man with a 65-mm mixed solid-cystic TC extending toward the frontal lobe. Results: Postoperatively, Case 1 maintained stable endocrine function without replacement therapy, suggesting preservation of both anterior and posterior pituitary function. Case 2 developed permanent diabetes insipidus and growth hormone deficiency, whereas other anterior pituitary axes were preserved. Conclusion: The VISSE technique may enable GTR while preserving pituitary function to varying degrees in selected TC cases.