title: Role of Pre-Operative Blood Transfusion and Subcutaneous Fat Thickness as Risk Factors for Surgical Site Infection after Posterior Thoracic Spine Stabilization.
abstract: BACKGROUND
  Surgical site infections (SSIs) increase morbidity and mortality rates and generate additional cost for the healthcare system. Pre-operative blood transfusion and the subcutaneous fat thickness (SFT) have been described as risk factors for SSI in other surgical areas. The purpose of this study was to assess the impact of pre-operative blood transfusion and the SFT on the occurrence of SSI in posterior thoracic spine surgery.
  
  
  METHODS
  In total, 244 patients (median age 55 y; 97 female) who underwent posterior thoracic spine fusions from 2008 to 2012 were reviewed retrospectively. Patient-specific characteristics, pre-operative hemoglobin concentration/hematocrit values, the amount of blood transfused, and the occurrence of a post-operative SSI were documented. The SFT was measured on pre-operative computed tomography scans.
  
  
  RESULTS
  Surgical site infection was observed in 26 patients (11%). The SFT was 13 mm in patients without SSI and 14 mm in those with infection (p=0.195). The odds ratio for patients with pre-operative blood transfusion to present with SSI was 3.1 (confidence interval [CI] 1.4-7.2) and 2.7 (CI 1.1-6.4) when adjusted for age. There was no difference between the groups with regard to pre-operative hemoglobin concentration (p=0.519) or hematocrit (p=0.908). The SFT did not differ in the two groups.
  
  
  CONCLUSIONS
  Allogeneic red blood cell transfusion within 48 h prior to surgery was an independent risk factor for SSI after posterior fusion for the fixation of thoracic spine instabilities. Pre-operative blood transfusion tripled the risk, whereas SFT had no influence on the occurrence of SSI.
authors.affiliation: Division of Trauma Surgery, University of Zurich, Zurich, Switzerland.
authors.forename: Georg
authors.initials: G
authors.lastname: Osterhoff
authors.affiliation: Division of Trauma Surgery, University of Zurich, Zurich, Switzerland.
authors.forename: Laurin
authors.initials: L
authors.lastname: Burla
authors.affiliation: Division of Trauma Surgery, University of Zurich, Zurich, Switzerland.
authors.forename: Clément M L
authors.initials: CM
authors.lastname: Werner
authors.affiliation: Division of Trauma Surgery, University of Zurich, Zurich, Switzerland.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Jentzsch
authors.affiliation: Division of Trauma Surgery, University of Zurich, Zurich, Switzerland.
authors.forename: Guido A
authors.initials: GA
authors.lastname: Wanner
authors.affiliation: Division of Trauma Surgery, University of Zurich, Zurich, Switzerland.
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Simmen
authors.affiliation: Division of Trauma Surgery, University of Zurich, Zurich, Switzerland.
authors.forename: Kai
authors.initials: K
authors.lastname: Sprengel
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011300:Preoperative Care / Q000009:adverse effects*; D012189:Retrospective Studies; D012307:Risk Factors; D013122:Spinal Diseases / Q000601:surgery*; D050151:Subcutaneous Fat / Q000033:anatomy & histology*; D013530:Surgical Wound Infection / Q000453:epidemiology*; D019616:Thoracic Surgical Procedures / Q000009:adverse effects*; D013904:Thoracic Vertebrae / Q000601:surgery*; D065227:Transfusion Reaction