According to Woojin Cho (Montefiore Medical Center, the University Hospital for Albert Einstein College of Medicine, New York, USA), who presented at the 25th International Meeting on Advanced Spine Techniques (IMAST; July 11-14, Los Angeles, USA), spinal surgeons continue to wrongly recommend bariatric surgery to obese patients prior to lumbar fusion surgery to reduce the risk of developing post-operative complications. The research presented by Cho contradicts this recommendation, with rapid body weight reduction prior to lumbar fusion surgery associated with poorer post-operative outcomes.
The authors aimed to compare the rates of the development of post-operative complications in patients who either did or did not undergo previous bariatric surgery and massive weight loss prior to lumbar fusion surgery for lower back pain.
Patients who underwent lumbar fusion surgery present on the National Surgical Quality Improvement Program (NSQIP) dataset spanning 2005–2015 were included in the study. Patients were identified and stratified into groups based on significant weight loss, defined as: 10% weight loss within the six months prior to lumbar fusion surgery. Exclusion criteria included a history of malignancy or chronic disease.
Of the 39,742 patients who underwent the procedure, 129 (3.2%) met the criteria for significant weight loss, and were subsequently matched with a randomised non-weight loss patient based on age, sex, smoking status and BMI, to act as a control. The two groups were compared in terms of surgical outcomes, including length of hospital stay, surgical site infections and deep vein thrombosis.
Interestingly, compared with the non-weight loss group, the weight loss group had significantly longer length of stay (9.7 vs. 4 days for the weight loss group, p<0.05), whilst the weight loss group experienced significantly more surgical site infections (8 vs. 3 among the non-weight loss group, p<0.05).
Furthermore, the number of transfusion occurrences and deep vein thrombosis were also significantly higher in the weight-loss group compared to the non-weight loss group (40 and 5 vs. 20 and 0, p<0.05, respectively).
Cho concluded that the study indicates a statistically significant association between massive weight loss prior to lumbar fusion surgery (greater than 10% of total body weight) and the development of post-operative conditions. He goes on to suggest reasons for this finding, based on several studies that have followed patients who underwent post-bariatric body contouring plastic surgery procedures.
According to Cho, these studies indicate that post-bariatric macro and micronutrient deficiencies (Protein, Vitamin A, D, B6, B12, Folate, Zinc and Iron) are present in patients, subsequently impacting on wound healing and immune function. He suggests that worse post-operative outcomes in weight loss patients may therefore be due to deficiencies in nutrients.
Future studies, he noted, may include nutritional supplementation prior to lumbar fusion surgery, and may take into consideration the timing of spinal surgery after bariatric surgery.