Hyponatremia and Acute Kidney Injury Following Spine Surgery.

The rates and risk factors of postoperative hyponatremia and acute kidney injury (AKI) were examined in spine surgery patients. A 2-year retrospective review of 348 patients was performed. Patients were instructed to take their routine nonsteroidal anti-inflammatory drugs and antihypertensive medications the morning of surgery. Postoperative hyponatremia and AKI were studied. Statistical analysis included bivariate and multivariable logistic regression analysis with odds ratio and quantile regression model. Thirty-eight percent of patients (133/348) had postoperative hyponatremia (serum sodium < 135 mEq/L). Seven percent (24/348) had AKI (0.3 mg/dL or > 50% increase in baseline serum creatinine). On the multivariable logistic regression model, two factors remained significant for hyponatremia: preoperative sodium level and operative time. Body mass index and use of preoperative angiotensin blocking medications were significant for AKI. Patients with hyponatremia and AKI demonstrated a longer length of hospital stay. In conclusion, postoperative hyponatremia (38%) and AKI (7%) are common following spine surgery. (Journal of Surgical Orthopaedic Advances 34(1):041-045, 2025).