title: Is surgical case order associated with increased infection rate after spine surgery?
abstract: METHODS
  Retrospective database review.
  
  
  OBJECTIVE
  To determine whether surgical site infections are associated with case order in spinal surgery.
  
  
  BACKGROUND
  Postoperative wound infection is the most common complication after spinal surgery, with incidence varying from 0.5% to 20%. The addition of instrumentation, use of preoperative prophylactic antibiotics, length of procedure, and intraoperative blood loss have all been found to influence infection rate. No previous study has attempted to correlate case order with infection risk after surgery.
  
  
  METHODS
  A total of 6666 spine surgery cases occurring between January 2005 and December 2009 were studied. Subjects were classified into 2 categories: fusion and decompression. Case order was determined, with each procedure labeled 1 to 5 depending on the number of previous cases in the room. Variables such as the American Society of Anesthesiologists score, number of operative levels, wound class, age, sex, and length of surgery were also tracked. A step-down binary regression was used to analyze each variable as a potential risk factor for infection.
  
  
  RESULTS
  Decompression cases had a 2.4% incidence of infection. Longer surgical time and higher case order were found to be significant risk factors for lumbar decompressions. Fusion cases had a 3.5% incidence of infection. Posterior approach and revision cases were significant risk factors for infection in cervical cases. For lumbar fusion cases, longer surgical time, higher American Society of Anesthesiologists score, and older age were all significant risk factors for infection.
  
  
  CONCLUSIONS
  Decompressive procedures performed later in the day carry a higher risk for postoperative infection. No similar trend was shown for fusion procedures. Our results identify potential modifiable risk factors contributing to infection rates in spinal procedures. Specific risk factors, although not defined in this study, might be related to contamination of the operating room, cross-contamination between health care providers during the course of the day, use of flash sterilization, and mid-day shift changes.
authors.affiliation: Department of Orthopedics, Rothman Institute, Thomas Jefferson University, Philadelphia, PA, USA.
authors.forename: Jordan
authors.initials: J
authors.lastname: Gruskay
authors.forename: Christopher
authors.initials: C
authors.lastname: Kepler
authors.forename: Jeremy
authors.initials: J
authors.lastname: Smith
authors.forename: Kristen
authors.initials: K
authors.lastname: Radcliff
authors.forename: Alexander
authors.initials: A
authors.lastname: Vaccaro
mesh_terms: D019072:Antibiotic Prophylaxis; D001071:Appointments and Schedules; D016009:Chi-Square Distribution; D019299:Decompression, Surgical / Q000009:adverse effects*; D004866:Equipment Contamination / Q000517:prevention & control; D006801:Humans; D015994:Incidence; D017053:Infection Control / Q000379:methods; D016015:Logistic Models; D016017:Odds Ratio; D010561:Personnel Staffing and Scheduling; D015143:Philadelphia; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013123:Spinal Fusion / Q000009:adverse effects*; D013131:Spine / Q000601:surgery*; D013530:Surgical Wound Infection / Q000453:epidemiology / Q000382:microbiology* / Q000517:prevention & control; D013997:Time Factors; D016896:Treatment Outcome