Predictive Value of Lymphocyte Percentage and CRP Level for Early Detection of Deep Surgical Site Infection Following Posterior Lumbar Spinal Surgery

Objective: To investigate the predictive value of laboratory predictors, such as C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), white blood cell (WBC) count, and WBC differential count, for the early diagnosis of deep surgical site infection (SSI) after posterior lumbar spinal surgery. We also sought to determine the diagnostic thresholds for these markers. Methods: A total of 243 patients participated in the study: 11 patients who developed deep SSI after lumbar spinal surgery (SSI group) and 232 non-SSI patients as controls (non-SSI group). White blood cell (WBC) count, WBC differential count, CRP level, and ESR were determined 1 day before surgery and on postoperative day (POD) 1, POD3, and POD7. The diagnostic thresholds for these markers were determined with the receiver operating characteristic curve. Results: CRP, ESR, and WBC were significantly higher in the SSI group than in the non-SSI group on POD3 and POD7 ( P < 0.05). The lymphocyte percentage was significantly lower in the SSI group, compared with the non-SSI group, on POD3 ( P < 0.05). Analysis of the receiver operating characteristic curve revealed that lymphocyte percentage 26 mg/L on POD7 (sensitivity 90.9%, specificity 87.7%, area under the curve [AUC] 0.954) were significant laboratory predictors for the early detection of SSI. Conclusion: Lymphocyte percentage 26.5 mg/L on POD7 are reliable predictors for SSI after posterior lumbar spinal surgery.