title: Risk factors for postoperative infection following posterior lumbar instrumented arthrodesis.
abstract: BACKGROUND
  Surgical site infection in the spine is a serious postoperative complication. Factors such as posterior surgical approach, arthrodesis, use of spinal instrumentation, age, obesity, diabetes, tobacco use, operating-room environment, and estimated blood loss are well established in the literature to affect the risk of infection. The goal of this study was to analyze and identify independent risk factors for surgical site infection among spine patients undergoing posterior lumbar instrumented arthrodesis.
  
  
  METHODS
  The medical records of 3218 patients who underwent posterior lumbar instrumented arthrodesis from January 2000 to December 2006 were reviewed to identify those who developed a postoperative infection (eighty-four patients; 2.6%). The size of this single-institution patient group allowed construction of a multivariate logistic regression model to evaluate the independent associations of potential risk factors for surgical site infection in the spine.
  
  
  RESULTS
  In the final regression model, obesity, estimated intraoperative blood loss, ten or more people in the operating room, a dural tear, history of diabetes, chronic obstructive pulmonary disease, coronary heart disease, and osteoporosis were critical risk factors for the onset of spinal surgical site infection. Obesity and a history of chronic obstructive pulmonary disease were the strongest risk factors for postoperative spinal infection after adjusting for all other variables. The most common pathogen was methicillin-resistant Staphylococcus aureus with a prevalence of 34.5%. This study established a single institution infection rate for posterior lumbar instrumented arthrodesis at 2.6%.
  
  
  CONCLUSIONS
  This analysis confirms previously demonstrated risk factors for postoperative infection while reporting on new potential independent risk factors of osteoporosis, chronic obstructive pulmonary disease, and dural tears in the setting of posterior lumbar instrumented arthrodesis. Areas of new research can focus on the roles these novel factors may play in the pathogenesis of surgical site infections in the spine.
authors.affiliation: Spine Surgery Service, Department of Orthopedic Surgery, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021, USA.
authors.forename: Stelios
authors.initials: S
authors.lastname: Koutsoumbelis
authors.forename: Alexander P
authors.initials: AP
authors.lastname: Hughes
authors.forename: Federico P
authors.initials: FP
authors.lastname: Girardi
authors.forename: Frank P
authors.initials: FP
authors.lastname: Cammisa
authors.forename: Eileen A
authors.initials: EA
authors.lastname: Finerty
authors.forename: Joseph T
authors.initials: JT
authors.lastname: Nguyen
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Gausden
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Sama
mesh_terms: D000328:Adult; D017677:Age Distribution; D001174:Arthrodesis / Q000009:adverse effects* / Q000295:instrumentation / Q000379:methods; D015331:Cohort Studies; D016001:Confidence Intervals; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D016268:Internal Fixators; D016015:Logistic Models; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D011859:Radiography; D012044:Regression Analysis; D012189:Retrospective Studies; D012307:Risk Factors; D017678:Sex Distribution; D013122:Spinal Diseases / Q000000981:diagnostic imaging / Q000601:surgery*; D013530:Surgical Wound Infection / Q000175:diagnosis / Q000453:epidemiology* / Q000628:therapy