2026 Poster Presentations
P224: PSEUDOCAPSULAR-BASED EXTRACAPSULAR RESECTION FOR PITUITARY ADENOMAS: ANATOMICAL AND SURGICAL PRINCIPLES
Srikant Chakravarthi, MD, MS; Ruth Yael Martinez Hernandes,, MD; Ernesto Leon; Jorge Marin; Alejandro Monroy-Sosa; Hospital General Tlahuac ISSSTE
Introduction: Pituitary adenomas, generally, are benign tumors. They may be considered aggressive/malignant if they invade the cavernous sinus, optic system, and/or the third ventricle. In practice, there are two techniques to remove the tumor bulk: intracapsular and extracapsular. “Pseudocapsular” dissection can be defined as the separation of the plane between the tumor pseudocapsule and the normal pituitary gland. Tumor cells can infiltrate the pseudocapsule, potentially resulting in recurrence.
Objectives:
1) To organize the sellar, parasellar and suprasellar anatomy based on a newly described “Cube Model”;
2) To describe the surgical/technical nuances of pseudocapsular resection;
3) To assess its potential clinical benefit in a patient series.
Methods:
Anatomical: The sellar, parasellar and suprasellar regions were topographically organized in a “Cube Model”, 1) Anterior plane; constitutes the anterior wall of the sella, tuber, limbus and carotid prominences, 2) Lateral plane; both sides of the pituitary ligaments, dura and cavernous sinus, 3) Inferior plane; the sellar floor, 4) Superior plane; arachnoid and sellar diaphragm, and 5) Posterior plane; the dorsum sellae and the posterior clinoid process.
Surgical/Technical: Extracapsular resection, through en bloc or piecemeal resection, was performed. Anatomical landmarks of the sellar region were the middle optical recess, middle clinoid process, and the falciform ligament.
Patient series: Single-surgeon retrospective study was performed in 50 patients; functional and non-functional tumors were included. Surgical and endocrinological outcomes and complications were evaluated.
Results: Wide, bilateral exposure of the sellar, parasellar and suprasellar regions allowed for sufficient exposure of relevant anatomical landmarks, including medial opticocarotid recess, middle clinoid process, and paraclinoid and paracavernous carotids. The sellar dura was opened in a rectangular fashion. The next step was to separate the pseudocapsule of the tumor adjacent to the cavernous sinus laterally. Posteriorly, separation between the pseudocapsule and the arachnoid plane was identified and allowed for tumor removal and localization of the pituitary gland. In cases of disruption of the arachnoid plane, the pituitary stalk was observed. Separation between the tumor and the cavernous sinus allowed for observation of the internal carotid artery; in 5 cases, the tumor invaded the cavernous sinus. In all patients, the pituitary gland was observed.
Extracapsular tumor resection was performed in 50 patients; 33 were non-functional and 7 were functional (2 prolactinomas and 5 growth hormone secreters). Total resection was performed in 49 cases, with one case leading to a subtotal resection. Intraoperative CSF leakage was observed in 20 patients and 2 patients presented with postoperative CSF fistula, which were subsequently reintervened. Temporary diabetes insipidus was observed in 34 patients, with one patient being permanent. Three patients required post-surgical hormone replacement. Visual field improved in all patients.
Conclusion: Pseudocapsular resection is a technically feasible and safe approach; permitting preservation of the intact pituitary gland (potentially resulting in less need for hormonal replacement) and prevention of tumor recurrence. The newly described “Cube Model” for systematic identification of surrounding structures, may help guide the surgeon in more effective tumor resection.