Usefulness of Ultrasound in Assessing the Impact of Bariatric Surgery on Body Composition: a Pilot Study

Background Bariatric surgery (BS) has a significant impact on body composition. The purpose of the study is to evaluate the usefulness of musculoskeletal ultrasound (MUS) to bioelectrical impedance (BIA) in the follow-up of patients undergoing BS in terms of body composition and quality of life (QoL). Methods This is a prospective pilot study including 32 subjects (75% female, mean age: 49.15 ± 1.9 years) who underwent BS. Fat mass (FM), lean mass (LM), and skeletal muscle index (SMI) were calculated by BIA. MUS measured subcutaneous fat (SF) and thigh muscle thickness (TMT) of the quadriceps. QoL was assessed by the Moorehead-Ardelt questionnaire. All these measurements were performed 1 month prior to BS and at 12-month follow-up. Results The mean BMI decreased by 6.63 ± 1.25 kg/m 2 ( p =0.001). We observed significant reductions in FM ( p =0.001) and SF ( p =0.007) and in LM ( p =0.001) but not in SMI and TMT. We found a correlation between the FM and SF (pre-surgical, r =0.42, p =0.01; post-surgical, r =0.52, p =0.003) and between SMI and TMT (pre-surgical, r =0.35, p =0.04; post-surgical, r =0.38, p =0.03). QoL test showed significant improvement ( p =0.001). In addition, a correlation between the QoL questionnaire and TMT post-surgery ( r =0.91, p =0.019) was observed. However, we did not find any statistically significant correlation between QoL assessment and SMI or LM. Conclusions Our results suggest that MUS can be complementary to BIA for the evaluation and the follow-up of body composition after BS. TMT of quadriceps can provide relevant information about regional sarcopenia and has a significant correlation with QoL. Graphical Abstract