title: Risk factors for surgical site infections following spinal fusion procedures: a case-control study.
abstract: BACKGROUND
  Spinal fusion procedures are associated with a significant rate of surgical site infection (SSI) (1%-12%). The goal of this study was to identify modifiable risk factors for spinal fusion SSIs at a large tertiary care center.
  
  
  METHODS
  A retrospective, case-control (1:3 ratio) analysis of SSIs following posterior spine fusion procedures was performed over a 1-year period. Clinical and surgical data were collected through electronic database and chart review. Variables were evaluated by univariate analysis and multivariable logistic regression.
  
  
  RESULTS
  In total, 57 deep SSIs were identified out of 1587 procedures (3.6%). Infections were diagnosed a mean of 13.5 ± 8 days postprocedure. Staphylococcus aureus was the predominant pathogen (63%); 1/3 of these isolates were methicillin resistant. Significant patient risk factors for infection by univariate analysis included ASA score >2 and male gender. Among surgical variables, infected cases had significantly higher proportions of staged procedures and thoracic level surgeries and had a greater number of vertebrae fused. Notably, infected fusion procedures had a longer duration of closed suction drains than controls (5.1 ± 2 days vs 3.4 ± 1 day, respectively; P < .001). Drain duration (unit odds ratio [OR], 1.6 per day drain present; 95% confidence interval [CI], 1.3-1.9), body mass index (OR, 1.1; 95% CI, 1.0-1.1), and male gender (OR, 2.7; 95% CI, 1.4-5.6) were significant risk factors in the multivariate analysis.
  
  
  CONCLUSIONS
  Prolonged duration of closed suction drains is a strong independent risk factor for SSI following instrumented spinal fusion procedures. Therefore, removing drains as early as possible may lower infection rates.
authors: Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.
authors: Shilpa B
authors: SB
authors: Rao
authors: Gustavo
authors: G
authors: Vasquez
authors: James
authors: J
authors: Harrop
authors: Mitchell
authors: M
authors: Maltenfort
authors: Natalie
authors: N
authors: Stein
authors: George
authors: G
authors: Kaliyadan
authors: Frank
authors: F
authors: Klibert
authors: Richard
authors: R
authors: Epstein
authors: Ashwini
authors: A
authors: Sharan
authors: Alexander
authors: A
authors: Vaccaro
authors: Phyllis
authors: P
authors: Flomenberg
mesh_terms: D000328:Adult; D000368:Aged; D001419:Bacteria / Q000145:classification / Q000302:isolation & purification; D016022:Case-Control Studies; D004322:Drainage / Q000009:adverse effects; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D013123:Spinal Fusion / Q000009:adverse effects*; D013530:Surgical Wound Infection / Q000453:epidemiology* / Q000382:microbiology