Radiologic Predictors for Extent of Resection in Pituitary Adenoma Surgery. A Single-Center Study.

Background: Preoperative radiologic evaluation of pituitary adenomas is essential. Despite the efforts made to determine the achieved resection grade after pituitary adenoma surgery, there is a high level of disagreement among all the available classifications and measurement methods used. Our study aimed to determine pituitary adenoma imaging features, easily obtained from preoperative magnetic resonance, which could be used as resection predictor variables. Second, we analyzed the usefulness of the ellipsoid method in pituitary adenoma volume determination.

Methods: Two-hundred and ninety-four pituitary adenomas, which were surgically treated in our department, were retrospectively analyzed. Age, gender, surgical approach, hormonal status, greater tumor diameter, volume, cavernous sinus invasion, and extent of resection were evaluated.

Results: One-hundred and forty-eight surgical procedures were conducted with a microsurgical transsphenoidal approach whereas 146 were conducted with an endoscopic endonasal approach. Gross total resection was achieved in 54.08% of cases. There were no significant differences in the extent of resection regarding the approach used, age, gender, or hormonal production by the tumor. Only Knosp grade (P < 0.001) and tumor volume (P < 0.05) had a statistically and independent significant relationship with the extent of resection. Furthermore, we found a high correlation between the calculated volume, using the ellipsoid method, and the volume measurement obtained with complex planimetry methods.

Conclusions: Pituitary adenoma volume and cavernous sinus invasion, graded with the Knosp scale, are 2 pituitary tumor features that, when used in combination, predict the complexity of the surgery and the difficulty of achieving gross total resection in pituitary adenoma surgery.