Does lumbar decompression in overweight patients assist in postoperative weight loss?

STUDY DESIGN  Systematic review. OBJECTIVE  To determine if there is a weight change in overweight patients following lumbar decompression with or without fusion for lumbar degenerative conditions. SUMMARY OF BACKGROUND  Anecdotal evidence suggests obesity is a risk factor for recurrent disc herniation or adjacent segment degeneration after lumbar surgery. Weight loss after surgery therefore may be important to reduce risk of these problems. Theoretically, patients who recover may be able to increase exercise tolerance and therefore the possibility for weight loss is more likely. If spine patients are similar to knee arthroplasty then it is unlikely that substantial weight loss will occur after surgery. If true, then other patient centered programs need to be developed to help obese patient's loss weight after spine surgery. METHODS  A systematic review of the English language literature was undertaken for articles published between 1970 and March 2010. Electronic databases and reference lists of key articles were searched to identify studies evaluating weight change in overweight patients following lumbar decompression with or without fusion for lumbar degenerative conditions. Two independent reviewers assessed the strength of evidence using the GRADE criteria assessing quality, quantity, and consistency of results. Disagreements were resolved by consensus. RESULTS  We identified two articles meeting our inclusion criteria. Body weight change following lumbar surgery in overweight patients varied between the two included studies. One study reported 6% of patients lost weight 34 months following lumbar surgery, while 35% gained body weight. A second study reported 40% lost weight while 41% gained weight 20 months post surgery. Evidence from these two studies are limited due to small sample sizes, different definitions of overweight, and unequal lengths of follow up between the two studies. CONCLUSION  There is no evidence that overweight patients consistently lose weight as a result of lumbar decompression with or without fusion. Two small studies suggest that an overweight patient undergoing lumbar surgery is as likely to gain weight as to lose weight following surgery.