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

• Main Authors: Eiichiro Iwata, Hideki Shigematsu, Munehisa Koizumi, Hiroshi Nakajima, Akinori Okuda, Yasuhiko Morimoto, Keisuke Masuda, Yasuhito Tanaka
• Format: Article
• Language: English
• Published: Korean Spine Society 2016-04-01
• Series: Asian Spine Journal
• Subjects: Surgical site infection; Laboratory marker; Lymphocyte; C-reactive protein; Instrumentation
• Online Access: http://www.asianspinejournal.org/upload/pdf/asj-10-220.pdf

Study DesignCase-control study.PurposeTo identify the characteristics of candidate indexes for early detection of surgical site infection (SSI).Overview of LiteratureSSI is a serious complication of spinal instrumentation surgery. Early diagnosis and treatment are crucial for the welfare of the patient postoperation.MethodsWe 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% at 4 days postoperatively, and a lymphocyte count of <1,000/µL at 4 days postoperatively. Statistical analysis was via Fisher's exact test and a p-value of <0.05 was considered significant.ResultsIn total, 85 patients were enrolled. Of these, five patients developed deep SSI. The sensitivity and specificity of each index were as follows: index 1, 20.0% and 77.5%; index 2, 20.0% and 83.8%; index 3, 40.0% and 97.5%; index 4, 40.0% and 86.3%; index 5, 0% and 96.3%; and index 6, 80.0% and 80.0%. A significant difference was noted for indexes 3 and 6.ConclusionsA CRP level 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.