title: Does obesity affect the surgical outcome and complication rates of spinal surgery? A meta-analysis.
abstract: BACKGROUND
  As obesity becomes more prevalent, it becomes more common among patients considering orthopaedic surgery, including spinal surgery. However, there is some controversy regarding whether obesity is associated with complications, failed reconstructions, or reoperations after spinal surgery.
  
  
  OBJECTIVE
  We wished to determine, in patients undergoing spine surgery, whether obesity is associated with (1) surgical site infection, (2) mortality and the need for revision surgery after spinal surgery, and (3) increased surgical time and blood loss.
  
  
  METHODS
  A systematic literature search was performed to collect comparative or controlled studies that evaluated the influence of obesity on the surgical and postoperative outcomes of spinal surgery. Two reviewers independently selected trials, extracted data, and assessed the methodologic quality and quality of evidence. Pooled odds ratios (OR) and mean differences (MD) with 95% CIs were calculated using the fixed-effects model or random-effects model. Data were analyzed using RevMan 5.1. MOOSE criteria were used to ensure this project's validity. Thirty-two studies involving 97,326 patients eventually were included.
  
  
  RESULTS
  Surgical site infection (OR, 2.33; 95% CI, 1.94-2.79), venous thromboembolism (OR, 3.15; 95% CI, 1.92-5.17), mortality (OR, 2.6; 95% CI, 1.50-4.49), revision rate (OR, 1.43; 95% CI, 1.05-1.93) operating time (OR, 14.55; 95% CI, 10.03-19.07), and blood loss (MD, 28.89; 95% CI, 14.20-43.58), were all significantly increased in the obese group.
  
  
  CONCLUSIONS
  Obesity seemed to be associated with higher risk of surgical site infection and venous thromboembolism, more blood loss, and longer surgical time. Future prospective studies are needed to confirm the relationship between obesity and the outcome of spinal surgery.
authors.affiliation: Orthopaedics Key Laboratory of Gansu Province, Department of Orthopaedics, Second Hospital of Lanzhou University, No. 82 Cuiyingmen, Chengguan District, Lanzhou, Gansu, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Jiang
authors.forename: Yuanjun
authors.initials: Y
authors.lastname: Teng
authors.forename: Zhenzhen
authors.initials: Z
authors.lastname: Fan
authors.forename: Shahidur
authors.initials: S
authors.lastname: Khan
authors.forename: Yayi
authors.initials: Y
authors.lastname: Xia
mesh_terms: D016063:Blood Loss, Surgical; D006801:Humans; D009765:Obesity / Q000150:complications* / Q000401:mortality; D016017:Odds Ratio; D019637:Orthopedic Procedures / Q000009:adverse effects* / Q000401:mortality; D011183:Postoperative Complications / Q000209:etiology* / Q000401:mortality / Q000601:surgery; D012086:Reoperation; D012307:Risk Factors; D013131:Spine / Q000601:surgery*; D013530:Surgical Wound Infection / Q000209:etiology / Q000401:mortality / Q000601:surgery; D013997:Time Factors; D016896:Treatment Outcome; D054556:Venous Thromboembolism / Q000209:etiology / Q000401:mortality / Q000601:surgery