Pituitary Stalk Morphology as a Predictor of New-Onset Adrenocortical Insufficiency and Arginine Vasopressin Deficiency after Transsphenoidal Resections of Pituitary Macroadenomas: A Retrospective Single-Center Study with a Focus on iMRI

SIMPLE SUMMARY: Common complications of transsphenoidal surgery for pituitary macroadenomas include new-onset adrenocortical insufficiency and arginine vasopressin deficiency. New-onset adrenocortical insufficiency is especially challenging to detect early and entails prolonged therapy. We performed a retrospective, monocentric analysis of pituitary stalk morphology in intraoperative MRI during 48 transsphenoidal surgeries for macroadenoma. An intraoperative thickening of the pituitary stalk was identified as an easy-to-acquire predictor of these endocrinological insufficiencies and, thus, might aid early detection. Still, these findings need to be validated in future prospective studies. ABSTRACT: Background: A new-onset adrenocortical insufficiency (NAI) is the most critical postoperative endocrinological complication after transsphenoidal surgery for macroadenomas. Because of increased mortality risk, arginine vasopressin deficiency (AVP-D) is also a relevant postoperative complication. This study aimed to identify easy-to-acquire magnet resonance imaging (MRI) aspects of the pituitary stalk to predict these insufficiencies after transsphenoidal surgery. Methods: Pituitary stalk morphology was reviewed intraoperatively and three months postoperatively in the MRIs of 48 transsphenoidal surgeries for macroadenomas. NAI was validated in endocrinological follow-up controls 10–14 months post-surgery. Results: Intraoperative pituitary stalk diameters were 0.5 mm larger in patients who developed NAI and AVP-D. The odds ratio was 29 for NAI and 6 for AVP-D in binary regression analysis. A value of 2.9 mm was identified as the optimal cut-off for the minimal pituitary stalk diameter regarding NAI, with a high specificity of 89%. There was no difference in pituitary stalk diameter regarding these insufficiencies three months post-surgery. Conclusions: We identified an increased pituitary stalk diameter in intraoperative MRIs as a predictive factor of NAI and AVP-D after transsphenoidal surgery. These findings might improve the early detection of NAI and, thus, optimal management. However, validating these retrospective findings in prospective studies is obligatory.