title: Risk factors for surgical site infection after posterior cervical spine surgery: an analysis of 5,441 patients from the ACS NSQIP 2005-2012.
abstract: BACKGROUND
  The incidence of surgical site infection (SSI) following posterior cervical surgery has been reported as high as 18% in the literature. Few large studies have specifically examined posterior cervical procedures.
  
  
  OBJECTIVE
  The study aims to examine the incidence, timing, and risk factors for SSI following posterior cervical surgery.
  
  
  METHODS
  This is a retrospective cohort study of prospectively collected data in a national surgical outcomes database.
  
  
  METHODS
  The sample includes patients who underwent posterior cervical spine surgery between 2005 and 2012 identified in the American College of Surgeons National Surgical Quality Improvement Project (ACS NSQIP) Participant Use Data File.
  
  
  METHODS
  The 30-day rate of postoperative SSI, timing of diagnosis, and associated risk factors were determined.
  
  
  METHODS
  The ACS NSQIP was used to identify 5,441 patients who underwent posterior cervical spine surgery by Current Procedural Terminology codes from 2005 to 2012. Thirty-day readmission data were obtained for 2011-2012. The incidence and timing of SSI were determined. Multivariable logistic regression analysis was then performed to identify significant risk factors.
  
  
  RESULTS
  Of the 5,441 patients identified as having undergone posterior cervical surgery, 3,724 had a posterior cervical decompression, 1,310 had a posterior cervical fusion, and 407 underwent cervical laminoplasty. Surgical site infection within 30 days was identified in 160 patients (2.94%), with 80 of those cases being superficial SSI. There was no significant difference in SSI rate among the three procedure groups. The average time for diagnosis of SSI was over 2 weeks. In 2011-2012, 36.9% of patients with SSI were readmitted within 30 days. Several significant predictors of SSI were identified in univariate analysis, including body mass index (BMI) >35, chronic steroid use, albumin <3, hematocrit <33, platelets <100, higher American Society of Anesthesiologists class, longer operative time, and longer hospital admission. Independent risk factors, including BMI >35 (odds ratio [OR]=1.78, p=.003), chronic steroid use (OR=1.73, p=.049), and operative time >197 minutes (OR=2.08, p=.005), were identified in multivariable analysis.
  
  
  CONCLUSIONS
  Optimization of preoperative nutritional status, serum blood cell counts, and operative efficiency may lead to a reduction in SSI rates. Obese patients and patients on chronic steroid therapy should be counseled on elevated SSI risk.
authors.affiliation: Mayo Clinic, 200 First St, SW, Rochester, MN 55905, USA.
authors.forename: Arjun
authors.initials: A
authors.lastname: Sebastian
authors.affiliation: Mayo Clinic, 200 First St, SW, Rochester, MN 55905, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Huddleston
authors.affiliation: Mayo Clinic, 200 First St, SW, Rochester, MN 55905, USA.
authors.forename: Sanjeev
authors.initials: S
authors.lastname: Kakar
authors.affiliation: Mayo Clinic, 200 First St, SW, Rochester, MN 55905, USA.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Habermann
authors.affiliation: Mayo Clinic, 200 First St, SW, Rochester, MN 55905, USA.
authors.forename: Amy
authors.initials: A
authors.lastname: Wagie
authors.affiliation: Mayo Clinic, 200 First St, SW, Rochester, MN 55905, USA. Electronic address: nassr.ahmad@mayo.edu.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Nassr
mesh_terms: D000328:Adult; D000368:Aged; D016208:Databases, Factual; D019299:Decompression, Surgical / Q000009:adverse effects* / Q000592:standards / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000453:epidemiology; D061646:Operative Time; D058996:Quality Improvement; D012189:Retrospective Studies; D012307:Risk Factors; D013123:Spinal Fusion / Q000009:adverse effects* / Q000592:standards / Q000706:statistics & numerical data; D013530:Surgical Wound Infection / Q000453:epidemiology*
keywords: ACS-NSQIP; Cervical spine surgery; Obesity; Posterior cervical; Surgical site infection