Preoperative Prediction of Small Bowel Length Using CT Scan and Tridimensional Reconstructions: a New Tool in Bariatric Surgery?

Abstract

During Roux-en-Y-gastric Bypass, the limb lengths are preoperatively determined regardless of individual small bowel length (SBL), which presents a great variability. Few studies highlighted anthropometric factors associated with SBL, and none attempted to predict SBL preoperatively. The aim of this study is to evaluate factors correlated to SBL (anthropometric and radiologic) and to establish a preoperative SBL prediction. In this single-center prospective study, 30 adult patients who underwent laparotomy with a preoperative CT scan were included. Intraoperative SBL measurement was performed with an umbilical tape. Anthropometric parameters were age, gender, height, and BMI. 2D radiological measurements consisted of subcutaneous thickness, abdominal diameters, waist circumference, and mesenteric root length. 3D radiological volumetric reconstructions consisted of whole small bowel and mesentery (WSBM), lean small bowel and mesentery (LSBM), and fat small bowel and mesentery (FSBM). Mean intraoperative measurement of SBL was 531± 105cm. Among the clinical and radiological measurements, the FSBM volume presented the greatest dispersion. Height (p < 0.02) and LSBM volume (p < 0.01) were significantly correlated to the SBL in univariate analysis. LSBM volume was the only measurement significantly associated with SBL in multivariate analysis (p < 0.006). From the multivariate model, a formula was created to predict SBL. The mean percentage difference between predicted and intraoperative SBL measurements for all patients was 13.7%, and 8.4% for obese patients. LSBM volume is significantly correlated to the SBL. A preoperative SBL prediction with low percentage error could be performed with LSBM volume.