The effect of low preoperative platelet count on adverse outcomes following lumbar microdiscectomy.

Background: Low preoperative platelet count, or thrombocytopenia, has previously been associated with increased complications in elective spine surgeries. No other study has investigated the effects of abnormal coagulation profiles on postoperative outcomes specific to lumbar microdiscectomy (MLD) using a propensity matched cohort. Methods: Patient data was retrospectively retrieved from the National Surgical Quality Improvement Program database using Current Procedural Terminology (CPT) code 63030 to isolate patients who solely underwent MLD. Data was collected from 2010 to 2019 and included preoperative, perioperative, and 30-day postoperative variables. Patients were grouped into four platelet categories for ANOVA analysis and pairwise comparisons: Severe Thrombocytopenia (≤100), Thrombocytopenia (101-150), Moderate (151-199), and Normal (200-450). Variables that were significant in the univariate analysis were used in the multivariate analysis to determine the likelihood of experiencing adverse postoperative events - unplanned return to the operating room and surgical site infection. A propensity matched analysis was performed to control for confounding variables. Results: A total of 64,747 patients were identified within the 10-year period. The results of the multivariate analysis and the propensity matched analysis showed no significant differences in low preoperative platelet count as an independent predictor of experiencing a return to the operating room or surgical site infection. Furthermore, patients who had diabetes, history of smoking, or had emergency cases were associated with a high likelihood of experiencing these negative adverse events. Conclusion: Thrombocytopenia does not appear to independently predict return to the operating room or postoperative infection following MLD. Proper preoperative management strategies should be implemented to monitor comorbidity burden which would otherwise influence adverse outcomes in patients with thrombocytopenia undergoing MLD.