Postoperative lymphocyte percentage and neutrophil-lymphocyte ratio are useful markers for the early prediction of surgical site infection in spinal decompression surgery

Purpose: Although the neutrophil-lymphocyte ratio (NLR) is a simple biomarker for inflammation, its diagnostic value for predicting surgical site infection (SSI) after spinal decompression surgery has not been extensively investigated. We aimed to determine the predictive value of NLR for SSI in patients undergoing spinal decompression surgery. Methods: We performed a retrospective observational study of patients who underwent spinal decompression surgery. Consecutive 254 patients were divided into an SSI group and a non-SSI group based on the presence of SSI. We evaluated which markers, including NLR, differed significantly between groups. We then determined the diagnostic cutoff values of these markers for the prediction of SSI based on the significance in the univariate analysis. Results: The incidence of SSI was 7 of 254 patients (2.8%). Univariate analysis showed that there were significant differences in the C-reactive protein (CRP) level at 1 day postoperatively; neutrophil and lymphocyte percentage and NLR at 3-4 days postoperatively; and CRP level, white blood cell count, neutrophil count and percentage, lymphocyte percentage, and NLR at 6-7 days postoperatively between SSI and non-SSI groups. Among these markers, the cutoff values of lymphocyte percentage and NLR at 3-4 days postoperatively for the prediction of SSI were <= 15.1% and >= 4.91, respectively. The cutoff values of lymphocyte percentage and NLR at 6-7 days postoperatively were <= 19.8% and >= 3.21, respectively. Conclusions: Lymphocyte percentage and NLR at 3-4 and 6-7 days postoperatively were useful markers for the early prediction of SSI in patients who had undergone spinal decompression surgery. These parameters may aid in identifying patients at higher risk of SSI after spinal decompression surgery.