Importance of Intraoperative Factors in Postoperative Arginine Vasopressin Deficiency after Pituitary Adenoma Surgery.

OBJECTIVE: Pituitary adenoma is the most frequent tumor in the sellar region. Arginine-vasopressin-deficiency (AVP-D), formerly known as central Diabetes-Insipidus (DI), is a common complication after pituitary surgeries. In this study, we reviewed patients with pituitary adenomas after endoscopic transsphenoidal surgery (ETSS), evaluated the incidence of postoperative AVP-D and determined associated risk-factors.

METHOD: We retrospectively studied 520 patients who underwent ETSS for pituitary adenomas, and evaluated perioperative risk factors and their associations with postoperative AVP-D. Patients who developed AVP-D were categorized in three groups: early, transient and permanent AVP-D.

RESULTS: Of the 520 patients, 24.8% experienced early-AVP-D and ten patients (1.9%) had transient-AVP-D. Permanent-AVP-D was observed in only six patients (1.1%). Gross-total-resection (GTR), hormonal remission, Pituitary stalk manipulation and Intraoperative cerebrospinal-fluid (CSF) leak were significantly associated with higher incidence of AVP-D (p-values=0.027, 0.002, < 0.001 and < 0.001 respectively). All patients who developed permanent-AVP-D had somatotroph adenomas. AVP-D was not found to be related with tumor size. The length of hospital stay was prolonged by AVP-D on average by 1.5 days. (p=0.018) DISCUSSION: Reported incidence of AVP-D has a considerably wide range. A consistent definition and grading for AVP-D will increase consistency and comparability among studies. Fortunately, most patients experience temporary imbalance, and only a few require long-term treatment. CSF-leak, GTR and hormonal remission were identified as risk factors for developing postoperative AVP-D. We believe intraoperative risk factors have the main role in postoperative AVP-D. The course of surgery and operative findings help us to plan selective postoperative patient monitoring and care.