Temporal Evolution of White Blood Cell Count and Differential: Reliable and Early Detection Markers for Surgical Site Infection Following Spinal Posterior Decompression Surgery

Abstract

Introduction For early detection of surgical site infection (SSI) following spinal decompression surgery, we compared temporal changes in the values of laboratory markers that are not affected by operative parameters. Methods The study included 302 patients, which were divided into an SSI group (patients who developed deep SSI) and a non-SSI group for analysis. We reviewed data on C-reactive protein level, total white blood cell (WBC) count, and WBC differential percentage and count before spinal decompression, on postoperative day 1, and on postoperative day 4. We identified laboratory markers that are not affected by operative parameters (operating time, intraoperative blood loss, and number of operative segments). Laboratory markers with a significant difference observed between the peak or nadir value and the value in the subsequent survey day were considered as an indicator of SSI. We examined the utility of each indicator by calculating sensitivity and specificity. Furthermore, we investigated the utility of the combination of all five indicators (wherein the recognition of one marker was considered positive). Results Temporal changes in five laboratory markers were considered indicators of SSI. The changes from postoperative day 1 to postoperative day 4 were as follows: (1) increased WBC count (42% sensitivity, 88% specificity), (2) increased neutrophil percentage (25% sensitivity, 96% specificity), (3) increased neutrophil count (25% sensitivity, 94% specificity), (4) decreased lymphocyte percentage (25% sensitivity, 95% specificity), and (5) decreased lymphocyte count (25% sensitivity, 85% specificity). The combination of these five markers showed a 50% sensitivity, 81% specificity, and 0.65 AUC. Conclusions Five markers were found to be reliable indicators of SSI following spinal decompression surgery because they were not affected by operative parameters. The combination of all five indicators had moderate sensitivity and high specificity. Therefore, this may be reliable and useful for the early detection of SSI.

A nomogram to predict postoperative surgical site infection of adult patients who received orthopaedic surgery: a retrospective study

“…Increased WBC count postoperatively is a reliable laboratory index, which prompts doctors to assess the surgical wound more carefully. More precise diagnostic tools, such as contrast-enhanced CT, contrast-enhanced MRI, and PET-CT, can be used accordingly to achieve the final diagnosis 27 . Hence, daily monitoring of WBC count can help doctors to estimate the incidence of SSI for patients postoperatively, which is accessible to most medical institutions and affordable for patients.…”