The utility of preoperative laboratories in predicting postoperative complications following posterolateral lumbar fusion.

Background Context: Several studies have suggested that laboratory results have minimal impact on clinical decision making in surgery. Despite the widespread use of preoperative testing in spine surgery and the large volume of posterolateral lumbar fusions (PLFs) being performed each year, no study has assessed the ability of preoperative laboratories to predict adverse events following PLF.

Purpose: The purpose of this study was to explore the relationship between commonly obtained preoperative laboratory results and postoperative complications following one- to two-level PLF.

Study Design: This is a retrospective study of prospectively collected data.

Patient Sample: The 2006-2013 American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was employed to identify all patients who underwent one- to two-level PLF.

Outcome Measures: The outcome variables of interest were 30-day postoperative complications, which were assessed as major complications, minor adverse events, and total complications.

Materials And Methods: Demographics, comorbidities, and perioperative characteristics were collected for each patient. Preoperative laboratories included sodium, blood urea nitrogen, creatinine, albumin, bilirubin, serum glutamic oxaloacetic transaminase, alkaline phosphatase, white blood cell count, hematocrit, platelet count, prothrombin time, international normalized ratio, and partial thromboplastin time. Bivariate analysis and multivariate logistic regression modeling were used to explore the relationship between abnormal preoperative laboratories and the incidence of postoperative complications.

Results: After controlling for age, ASA score, length of surgery, and all significant comorbidities, abnormal sodium (odds ratio [OR]=2.47, 95% confidence interval [CI]: 1.45-4.19, p=.001) and abnormal INR (OR=2.33, 95% CI: 1.09-4.98, p=.029) were significantly associated with the development of any complication. Sodium (OR=1.61, 95% CI: 1.01-2.54, p=.04) and platelets (OR=1.58, 95% CI: 1.02-2.44, p=.04) were associated with minor complications. Meanwhile, creatinine (OR=1.74, 95% CI: 1.02-2.99, p=.04) and platelets (OR=1.71, 95% CI: 1.02-2.89, p=.04) were significant predictors of major adverse events.

Conclusions: This study represents the first attempt to assess the utility of preoperative laboratories in predicting postoperative complications in PLF. Although the majority of laboratories were not significantly associated with adverse events, abnormal sodium values, INR, creatinine, and platelets were shown to be predictive of various complications.