Is it possible to predict the development of diabetes insipidus after pituitary surgery? Study of 241 endoscopic transsphenoidal pituitary surgeries.

PURPOSE: To identify presurgical and surgical factors associated with the development of diabetes insipidus (DI) after pituitary adenoma (PA) resection through an endoscopic endonasal transsphenoidal approach. METHODS: Data from 231 patients with functioning and non-functioning PAs who underwent an endoscopic endonasal transsphenoidal approach in the last ten years. RESULTS: 231 patients with 241 pituitary surgeries were included. Eighty-five percent harbored macroadenomas and 38.1% of them were invasive. After pituitary surgery, 12.5% (n = 30) developed transient DI and 5.0% (n = 12) permanent DI. The global risk of DI was higher in patients younger than 65 years (OR = 2.94, p = 0.029), with total tumoral resection (OR = 2.86, p = 0.007) and with diaphragm opening during pituitary resection (OR = 3.63, p = 0.0003). Once postoperative DI developed, the risk of permanent DI increased in those patients with larger PA (OR = 1.07 for each mm of craniocaudal diameter, p = 0.020), especially in those greater than 30 mm (OR = 8.33, p = 0.004). Moreover, diaphragm opening during pituitary resection (OR = 28.3, p = 0.018) predicted long-term DI independently of pituitary tumor size. The risk of permanent DI increased as PA craniocaudal diameter increased (r = 0.20, p = 0.002). CONCLUSION: In patients with PAs younger than 65 years, in whom diaphragm has been opened during pituitary surgery and/or with a total tumor resection, special hydric balance monitoring should be maintained in the postoperative period due to the increased risk of developing DI. The risk of permanent DI increases as PA craniocaudal diameter increased.