title: A methodological, systematic review of evidence-based independent risk factors for surgical site infections after spinal surgery.
abstract: OBJECTIVE
  To identify the independent risk factors, based on available evidence in the literature, for patients developing surgical site infections (SSI) after spinal surgery.
  
  
  METHODS
  Non-interventional studies evaluating the independent risk factors for patients developing SSI following spinal surgery were searched in Medline, Embase, Sciencedirect and OVID. The quality of the included studies was assessed by a modified quality assessment tool that had been previously designed for observational studies. The effects of studies were combined with the study quality score using a best-evidence synthesis model.
  
  
  RESULTS
  Thirty-six observational studies involving 2,439 patients with SSI after spinal surgery were identified. The included studies covered a wide range of indications and surgical procedures. These articles were published between 1998 and 2012. According to the quality assessment criteria for included studies, 15 studies were deemed to be high-quality studies, 5 were moderate-quality studies, and 16 were low-quality studies. A total of 46 independent factors were evaluated for risk of SSI. There was strong evidence for six factors, including obesity/BMI, longer operation times, diabetes, smoking, history of previous SSI and type of surgical procedure. We also identified 8 moderate-evidence, 31 limited-evidence and 1 conflicting-evidence factors.
  
  
  CONCLUSIONS
  Although there is no conclusive evidence for why postoperative SSI occurs, these data provide evidence to guide clinicians in admitting patients who will have spinal operations and to choose an optimal prophylactic strategy. Further research is still required to evaluate the effects of these above risk factors.
authors.affiliation: Department of Orthopaedics, Tianjin Medical University General Hospital, 154 Anshan Street, Heping District, Tianjin 300052, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Xing
authors.forename: Jian-Xiong
authors.initials: JX
authors.lastname: Ma
authors.forename: Xin-Long
authors.initials: XL
authors.lastname: Ma
authors.forename: Dong-Hui
authors.initials: DH
authors.lastname: Song
authors.forename: Jie
authors.initials: J
authors.lastname: Wang
authors.forename: Yang
authors.initials: Y
authors.lastname: Chen
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.forename: Shao-Wen
authors.initials: SW
authors.lastname: Zhu
authors.forename: Bao-Yi
authors.initials: BY
authors.lastname: Ma
authors.forename: Rui
authors.initials: R
authors.lastname: Feng
mesh_terms: D019317:Evidence-Based Medicine; D006801:Humans; D019637:Orthopedic Procedures / Q000009:adverse effects*; D012307:Risk Factors; D013131:Spine / Q000601:surgery*; D013530:Surgical Wound Infection / Q000209:etiology* / Q000517:prevention & control