Analysis of Preoperative Imaging as a Predictive Marker for Intraoperative and Postoperative Surgical Management in the Endoscopic Endonasal Resection of Pituitary Macroadenomas

Background: Macroadenomas are one of the most common pathologies encountered in skull base surgery. The primary surgical management goals are maximizing cytoreduction and achieving optic nerve decompression. Devastating intraoperative complications, such as carotid laceration or optic nerve damage, have been significantly reduced over the years through skull base anatomy and advances in imaging, optics, and instrumentation. However, postoperative hypothalamo–hypophyseal axis injuries and cerebrospinal fluid (CSF) leaks remain issues.

Objective: The objective of this study is to utilize preoperative MRI to predict the relative location of critical neuroanatomic structures, including the pituitary gland and diaphragm, to create a preoperative plan and an intraoperative map to enable a safer surgical resection.

Methods: Thirty surgical cases of pituitary macroadenomas (>2 cm) were prospectively analyzed. Three main elements were analyzed by a neuroradiologist on the preoperative MRI: gland location, diaphragm integrity, and sellar diaphragm ascent. The criterion for diaphragm disruption was irregularity or loss of enhancement along its perimeter. Diaphragm ascent was measured on sagittal MRI and was predicted to descend to the same degree after total resection. Pseudocapsular tumor dissection was also performed to preserve PG.

Results: Mean tumor diameter was 27.8 mm (20–62 mm). Partial or complete preoperative pituitary insufficiency was present in 15 patients (50%). After surgery, 2 (13%) completely recovered pituitary function, 12 (80%) remained unchanged, and 1 (3.3%) presented a new hormonal deficit. Among preoperative hormonally intact patients, one (7%) experienced a transient diabetes insipidus (DI). Among the 15 (50%) patients who were hormonally intact before surgery, 1 (7%) experienced a new hormonal deficit (adrenal insufficiency) and 1 (7%) developed transient DI that resolved within weeks. The diaphragm was predicted to be preserved in 24 (80%) cases, in 5 (17%) to be disrupted, and in 1 (3%) case it was unclear. Intraoperatively, the 24 intact-predicted diaphragms were confirmed. Among the five violated diaphragms, three (60%) were confirmed, one (20%) was preserved, and one (20%) was not evaluated because goal of surgery was ON decompression. The unclear case was found to be violated intraoperatively. The ascent of the diaphragm was an average of 11.61 mm (3–25 mm). Intraoperatively, an equivalent degree of descent was observed in all cases, except for the previous case. Three patients (10%) presented a postoperative CSF leak. Among them, only one was found to have a violated diaphragm preoperatively. Of the patients who presented with visual impairment, 16 (100%) experienced some degree of visual improvement after surgery with 6 (37.5%) regaining normal vision, 8 (50%) experiencing a significant improvement, and 2 (12.5%) having a slight improvement. Twenty-seven patients (90%) underwent gross total resection (GTR). Two (7%) patients had subtotal resection (STR) and one (3%) patient underwent partial resection of a giant macroprolactinoma.

Conclusion: Systematic preoperative radiological analysis using MRI and integration has the potential to assist and provide a guide for the surgeon in addressing pituitary tumors. Detailed preoperative MRI analysis, combined with a pseudocapsular dissection technique, offers a positive result in terms of postoperative preservation of pituitary function, diaphragm preservation, and reducing residual tumor.

No conflict of interest has been declared by the author(s).