"One-and-a-Half" Interdural Transcavernous Pituitary Transposition/Rotation for Protection of Hypophyseal Portal System in Adult Peripheral Retroinfundibular Craniopharyngioma.

Background And Objectives: Craniopharyngiomas originate from the pituitary stalk (PS) and extend along the pituitary-hypothalamic axis. Peripheral retroinfundibular craniopharyngiomas, particularly, may have worse surgery outcomes than other types. This study aims to investigate the advantage of using "one-and-a-half" interdural transcavernous pituitary transposition/rotation to dissect the tumor from the residual stalk and hypophyseal portal system for this subtype of craniopharyngioma.

Methods: From August 2018 to February 2023, patients with peripheral retroinfundibular craniopharyngioma underwent surgical treatment. We analyzed clinical information, surgical records, imaging, and examination findings. The surgical procedure, including "one-and-a-half" interdural transcavernous pituitary transposition and rotation, was explained. Postoperative follow-up included endocrinological tests, MRI examinations, and urination surveys.

Results: Among the 52 patients diagnosed with craniopharyngioma who underwent surgical treatment, 9 were classified as peripheral retroinfundibular craniopharyngioma, and they received "one-and-a-half" interdural transcavernous pituitary transposition and stalk rotation. In 6 cases, the residual PS and most of the hypophyseal portal system were preserved. Gross total resection was achieved in 5 patients and near total resection in 1 patient. One patient had a transection of the bilateral inferior hypophyseal arteries and 5 unilaterally. None experienced permanent diabetes insipidus, but varying degrees of anterior pituitary dysfunction postoperatively required hormone replacement therapy, which gradually decreased over time.

Conclusion: The natural anatomic corridor, "one-and-a-half" interdural transcavernous pituitary transposition, and stalk rotation provide increased working space compared with intradural or extradural pituitary transposition. Simultaneously rotating the tumor and pituitary enables a specific attack angle for lesion dissection after the anteriorly displaced residual stalk is rotated laterally. This approach preserves the residual PS and hypophyseal portal system, avoiding complications of diabetes insipidus and hypopituitarism. In most cases, only one side of the inferior hypophyseal artery needs to be sacrificed, ensuring normal pituitary function.