Onodera’s prognostic nutritional index (OPNI) as a Measure of Predicting Postoperative Complications in Spine Patients

Purpose This study aims to explore the utility of preoperative OPNI as a predictor of postoperative complications in spine surgical patients. Additionally, we aim to identify the values for spine surgical patients that delineate the threshold where patients may face an elevated risk of adverse surgical outcomes. Methods A retrospective review of spine cases identified at a Level 1 Trauma Center was conducted from January 2017 to March 2023. Exclusion criteria included inadequate lab values for OPNI calculation within 90 days preoperatively. Patient demographics, surgical characteristics, postoperative events and clinical outcomes within the 90-day postoperative window were collected and compared. Multivariate logistic regression was used to assess the predictive ability of OPNI, and a receiver operating characteristic (ROC) curve predicted the probability of not returning to the operating room based on OPNI score. Results 1964 patients were identified and 641 met inclusion criteria. The OPNI score was significantly lower in those with POC compared to those without POCs (43.9 vs 48.5, p = <0.0001). Logistic regression analysis demonstrated that an increase in OPNI score has significantly lower odds of postoperative complications (OR 0.96, 95% CI=0.94-0.98). ROC curve analysis identified an optimal cutoff value for lower odds of postoperative complications at 47.25. Conclusions Patients with a higher OPNI score were shown to have significantly lower odds of having POCs. OPNI score of 47.25 or higher was also associated with a lower likelihood of POCs. This study substantiates that OPNI is an independent risk factor for acute POCs in spine surgery patients.