Introduction: While it is known DI can occur due to direct intraoperative handling of the pituitary stalk, DI not infrequently develops when the surgeon does not physically manipulate the stalk. It is difficult and often unfeasible to reliably predict which patients are likely to develop DI in these instances. For the first time, we directly investigate if large changes in angulation of the pituitary stalk leads to DI following endoscopic resection of sellar lesions.
Methods: Patients undergoing endoscopic resection of sellar lesions were retrospectively reviewed. Pre and postoperative T-1 MRIs with contrast were analyzed. The trajectory of the pituitary stalk was measured against a horizontal reference in the sagittal and coronal planes. Differences between pre and postoperative angles (delta sagittal/coronal) were calculated. An independent samples t-test compared the delta sagittal/coronal angles between DI and non-DI patients.
Results: Fifty-eight patients underwent endoscopic for resection of sellar masses who had measurable stalk angles. Most patients were diagnosed with pituitary adenoma (n=48). Six DI patients had calculable delta sagittals and coronals with average stalk trajectories of 18.3° and 12.3°, respectively. In non-DI patients, the average delta sagittal and coronal was 18.7° and 17°, respectively. There was no statistical significance between DI vs. non-DI patients (Delta sagittal: p=.929, BCa 95% CI Bootstrap= -8.67, 12.40; Delta coronal, p=.554, BCa 95% CI Bootstrap= -7.33, 15.45).
Conclusions: Diabetes insipidus after endoscopic resection of sellar masses sometimes occurs when the pituitary stalk is not directly manipulated, and it is unclear what exactly triggers DI in these instances. There is no significant correlation between development of DI and change in angulation of the pituitary stalk following endoscopic resection. As a result, it remains difficult to predict development of DI when the surgeon does not directly manipulate the stalk and it should therefore not be used in clinical decision-making and counseling of the patient.
Patient Care: Post-operative diabetes insipidus is a well-known complication of endoscopic endonasal resection of sellar masses, and patients should be counseled preoperatively on this risk. Determining which patients may go into DI after surgery is difficult, and it has been thought some radiographic features may help determine that. Measuring the change in angulation of the pituitary stalk compared to before and after surgery did not serve as a reliable means to predict development of DI and therefore should not be used clinically to determine which patients are at high-risk of post-op DI.
Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe the importance of potentially predicting which patients go into DI following endoscopic resection of their sellar mass, 2) Discuss in small groups what post-op radiographic factors may lead to predicting patients at risk for developing DI, and 3) Identify other possible parameters for predicting DI based on routine post-op imaging following endoscopic resection of sellar masses.