Does obesity affect the surgical outcome and complication rates of spinal surgery? A meta-analysis.

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. QUESTIONS/PURPOSES: 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. CONCLUSION: 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.