Sleeve Gastrectomy and Roux-en-Y Gastric Bypass lead to Comparable Changes in Body Composition after Adjustment for Initial Body Mass Index.

Roux-En-Y Gastric Bypass (LRYGB) and sleeve gastrectomy (SG) are standardized procedures in bariatric surgery, but the superior method regarding weight loss is unclear [1, 2], with differences in initial weight being a relevant confounding variable [3]. Otto et al concluded that percentage of total weight loss (%TWL) is a valuable measurement tool, which can be used to assess and compare bariatric outcomes and abolish initial BMI differences [4]. BMI is not the reflection of the real metabolic profile of an obese patient, and it is unfortunate that the authors have not considered using body fat index BFI (total body fat/squared height), which would seem more adapted. BFI is the parameter of obesity—the most strongly associated to autonomic nervous system activity decrease [5]. Otto et al concluded that BSG and RYGB do not differ in terms of body composition and weight loss 1 year after surgery.^ However, we do not entirely agree with Otto et al; we agree that the bioelectrical impedance analysis (BIA) used for evaluation of body composition can only measure body fat, not different fat distribution, and is unable to distinguish visceral and subcutaneous fat, even if subcutaneous fat and BIA are significantly correlated [6]. However, visceral abdominal fat can be easily measured using an automatic segmentation technique. We are currently observing visceral abdominal fat automatic segmentation in patient with LRYGB or SG. Visceral abdominal fat was measured using images of multi-detector computed tomography (MDCT) of the abdomen and pelvis and a dedicated workstation (Aquarius 3D Workstation, TeraRecon, San Mateo, CA, USA). Body Fat Analysis tool uses region segmentation based on morphological analysis with CT value thresholding. This procedure takes less than 5 min including visual control of segmentation quality and manual corrections if necessary. An illustration of segmentation is presented in Fig. 1. As used in clinical practice preoperative CT to evaluate lithiasis disease and search NASH syndrome, this visceral abdominal fat segmentation does not require additional exploration.