Objective: The extended transplanum/transtuberculum endoscopic endonasal approach (EEA) serves as a versatile surgical technique for addressing suprasellar tumors, including craniopharyngiomas. However, the anatomical complexity of the structures located in the posterior sphenoid sinus may limit optimal safe exposure. The extent of bone removal across the planum sphenoidale, tubercular strut, sellar floor, and upper clivus can be tailored based on the relation of the tumor to the pituitary stalk. This study outlines the surgical nuances, aiming to minimize bony and dural exposure while ensuring a safe wide corridor for optimal access to suprasellar craniopharyngiomas.
Methods: The key steps to identify the anatomic landmarks for a customized bone drilling and dural opening are described based on the relationship of the tumors to the pituitary stalk. A series of cadaveric dissection photos is provided to delineate a safe surgical corridor spanning from the posterior ethmoid sinus to the interpeduncular fossa. Additionally, intraoperative findings from three cases are highlighted to illustrate the relation of the tumors to the surrounding neurovascular structures and distinctions in minimal exposures required for resection of various types of suprasellar craniopharyngiomas.
Results: Several key steps are applicable in the transtplanum/transtuberculum EAA to all types of suprasellar craniopharyngiomas, including complete removal of the tuberculum strut and bilateral medial opticocarotid recesses, along with the division of the superior intercavernous sinus. For infrachiasmatic/preinfundibular craniopharyngioma (Type I), the bone removal commences from the upper third of the sellar floor and encompasses variable lengths of the planum sphenoidale, always posterior to the posterior ethmoidal arteries and medial to the falciform ligaments. The dural opening extends from the upper third of the sellar dura to the limbus dura with a complete release of the diaphragm sella anteriorly to the stalk. For the transinfundibular craniopharyngioma (Type II), complete drilling of the sellar floor, extending to the posterior third of the planum, facilitates enough vertical angle of attack along the tumor’s axis of growth. The dural opening mirrors that of Type I, with complete exposure of the pituitary gland. The exposure of the infrachiasmatic/retroinfundibular craniopharyngioma with extension to the anterior third ventricle (Type IIIa) needs complete drilling of the sellar floor dura extending to just a few millimeters anterior to the tubercular strut. Conversely, for the tumors with inferior extension to the interpeduncular fossa (Type IIIb), complete drilling of the sellar floor, along with upper clivus, dorsum sellae, and posterior clinoid process removal following intradural pituitary hemitransposition are typically necessary. The dural opening follows a pattern similar to Type II, with a more posteroinferior extension in Type IIIb to include the prepeduncular dura. The pituitary stalk scarification was unnecessary in the presented cases, and important perforating arteries were meticulously preserved. All patients had uneventful postoperative course without new neurological deficits or any tumor residual in postop MRI.
Conclusions: A customized extended EEA based on the careful preoperative evaluation of the tumor-stalk relationship ensures a safe surgical corridor for unrestricted maneuverability while avoiding unnecessary overexposure, which could prolong the surgical procedure and increase the perioperative complications.
