Lymphopenia and Elevated Blood C-Reactive Protein Levels at Four Days Postoperatively Are Useful Markers for Early Detection of Surgical Site Infection Following Posterior Lumbar Instrumentation Surgery

ABSTRACT

STUDY DESIGN: Case-control study. PURPOSE: To identify the characteristics of candidate indexes for early detection of surgical site infection (SSI). OVERVIEW OF LITERATURE SSI is a serious complication of spinal instrumentation surgery. Early diagnosis and treatment are crucial for the welfare of the patient postoperation. METHODS: We retrospectively reviewed laboratory data of patients who underwent posterior lumbar instrumentation surgery for degenerative spine disease. The sensitivity and specificity of six laboratory markers for early detection of SSI were calculated greater elevation of the white blood cell count at day 7 than at day 4 postoperatively, greater elevation of the C-reactive protein (CRP) level at day 7 than at day 4 postoperatively, a CRP level of >10 mg/dL at 4 days postoperatively, neutrophil percentage of >75% at 4 days postoperatively, a lymphocyte percentage of 10 mg/dL at 4 days postoperatively would be useful for definitive diagnosis of SSI, and a lymphocyte count of <1,000/µL at 4 days postoperatively would be a useful screening test for SSI. Although laboratory markers for early detection of SSI have been frequently reported, we believe that it is important to understand the characteristics of each index for a precise diagnosis.