Trends in weight and body mass index after spinal surgery for degenerative disease

Background: Currently, 37% of adults in the United States are obese, and 34% are overweight. Obesity poses a particularly complex challenge in spinal surgery management, whereby risk of adverse surgical outcomes increases with increased body mass index (BMI). When patients are counseled to reduce weight to levels associated with acceptable surgical risks, patients often respond that their spinal problems prohibit the exercise needed to lose the required weight and counter that surgery will allow for increased activity and thereby facilitate weight loss. A retrospective study of a US Veterans Affairs (USVA) nationwide patient database was undertaken. Methods: A request was made of the USVA Corporate Data Warehouse for data on all patients undergoing elective spine surgery for degenerative conditions over a 10-year period. Results: The mean preoperative age of 65 667 patients identified was 59 years. The mean preoperative weight was 91.8 kg, and BMI was 29.2. Before surgery, 26 772 patients had a BMI of.30. After surgery, 12 564 (46.9%) lost at least 2.3 kg, 9450 (35.3%) gained at least 2.3 kg, and 4758 (17.8%) were unchanged. After surgery, 4853 (18.1%) lost at least 11.3 kg and 1360 (5.1%) lost at least 22.7 kg. At a mean of 1.9 years after index surgery, mean postoperative weight was 92.5 kg, and BMI was 29.4. Of the 65 667 patients, 23 125 (35.2%) patients lost at least 2.3 kg, 27 571 (42.0%) gained at least 2.3 kg, and 14 971 (23.0%) remained within 2.3 kg of their preoperative weight. Conclusion: The study results will aid in counseling patients regarding realistic expectations about weight loss after spinal surgery.