術後4日目リンパ球数と7日目CRP値は信頼度の高い有用な手術部位感染の指標である : 脊椎後方インストゥルメンテーション手術における検討

STUDY DESIGN: A case-control study. OBJECTIVE: The objective of this study is to identify biochemical markers for surgical site infection (SSI) in posterior instrumented spinal fusion that are not affected by operative circumstances and to determine diagnostic cutoffs for these markers. SUMMARY OF BACKGROUND DATA: Numerous biochemical markers may be used for early detection of SSI; however, these markers may be affected by operative factors. METHODS: We reviewed data on C-reactive protein level and total white blood cell count and differential count before instrumented spinal fusion and at 1, 4, and 7 days postoperatively. The 141 patients in our sample were divided into an SSI group (patients who developed deep SSI) and a no-SSI group. We determined which markers differed significantly between groups and identified those not affected by operative circumstances (operating time, intraoperative blood loss, number of fusion segments) in the no-SSI group. Then, we determined diagnostic cutoffs for these unaffected markers by using receiver-operating characteristic curves. RESULTS: Three markers were selected: lymphocyte count at 4 days postoperatively (cutoff 1180/μL, sensitivity 90.9%, specificity 65.4%, area under the curve [AUC] 0.80), lymphocyte count of at 7 days postoperatively (cutoff 4.4 mg/dL, sensitivity 90.9%, specificity 89.2%, AUC 0.95). CONCLUSION: Lymphocyte count at 4 and 7 days postoperatively and C-reactive protein level at 7 days postoperatively are reliable markers for SSI following instrumented spinal fusion. Lymphocyte count at 4 days should be useful for screening because of its high sensitivity and because it can be measured early. C-reactive protein level at 7 days should be useful for definitive diagnosis given its high sensitivity and specificity and large AUC.博士（医学）・甲第654号・平成28年7月8日Copyright © 2016 Wolters Kluwer Health, Inc. All rights reservedThis is a non-final version of an article published in final form in "http://dx.doi.org/10.1097/BRS.0000000000001501