Dual-energy X-ray Absorptiometry Was Used To Evaluate Early Postoperative Body Composition Changes In Obese Patients After Bariatric Surgery

Objective: To evaluate the changes of the systemic and different anatomic sites body composition in early after bariatric surgery by dual-energy X-ray absorption,and to further analysis the correlation of each body composition changes,at the same time a preliminary comparative analysis of laparoscopic Roux-en-Y gastric bypass and laparoscopic sleeve gastrectomy of the differences of body composition early changes,in order to improve the weight loss surgery medical provides a new direction.Methods: A total of 50 patients who underwent DXA examination in the fourth affiliated hospital of China medical university from January 2016 to October 2018 were included in this study,including 34 cases of laparoscopic sleeve gastrectomy(LSG)and 16 cases of laparoscopic Roux-en-Y gastric bypass(LRYGB).The body composition parameters of the systemic body and different anatomic sites of the body measured by DXA examination in 50 patients with weight loss before bariatric surgery,1 month and 3 months after bariatric surgery were retrospectively analyzed.Results: Body mass index(BMI),systemic fat mass(FM),systemic muscle mass,and systemic bone mineral density all decreased in the early after bariatric surgery.According to the analysis of different anatomic sites,the fat and muscle mass of each sites except to upper limb also showed a downward trend.The fat mass decreased most obviously in the abdominal region,the muscle content decreased more significantly in the trunk and abdominal region,and the bone density also decreased in some regions,especially in the pelvis.From the point of time,lose weight reduced after bariatric surgery systemic muscle mass mainly occurs in postoperative 1 month,3 months after falling slows,the muscle mass(1 month after change quantity VS postoperative 1 ~ 3 months quantity: 12.11±14.03,2.12±4.77)kg,and 1,3 months after BMI and body fat mass is continues to decline.The percentage of total body muscle mass change was positively correlated with the percentage of total body bone density change(1 month postoperative r=0.296,P=0.037;3 months postoperative r=0.374,P=0.007).Compared with LRYGB,LSG patients showed no significant difference in percentage reduction of fat mass,but a greater percentage reduction in total body muscle mass.One month after weight loss,the percentage of total body BMD decreased in LSG patients was significantly higher than that in LRYGB patients(LSG,LRYGB:2.78±3.45,0.50±2.19).Conclusion: Early postoperative weight loss can lead to a significant decrease in body mass index,fat mass,as well as the loss of muscle mass and bone mineral density.Fat mass,muscle mass and bone mineral density vary in different anatomic sites of the body.Muscle tissue loss occurred 1 month after bariatric surgery.Early changes in total muscle mass after bariatric surgery are positively correlated with changes in total bone density,so maintaining muscle mass helps protect bone mass from loss.There was no significant difference in the effect of fat loss between LSG and LRYGB in the early postoperative period,but 1 month after bariatric surgery,SG patients lost more non-adipose tissue components(muscle and bone density)than LRYGB patients.