Residual Gastric Volume Estimated with a New Radiological Volumetric Model: Relationship with Weight Loss After Laparoscopic Sleeve Gastrectomy

The volume of the gastric reservoir appears crucial to explain the success of laparoscopic sleeve gastrectomy (LSG) in the treatment of morbid obesity. The aims of this study were to describe a new, easy model to estimate gastric reservoir volume after LSG; to evaluate the volumetric changes 1 year after surgery; and to analyze their relationship with weight loss. This is a prospective observational study of all patients undergoing LSG in the Department of Surgery at our institution. The gastric reservoir was evaluated radiologically considering the image as a complex geometrical shape with two components: a cylinder (gastric body) and a truncated cone (antrum). Radiologic assessment using this new model was performed at 1 and 12 months after surgery. Moreover, body mass index and percentage of excess weight loss (%EWL) were evaluated at 3, 6, 12, and 18 months after LSG. Forty-five patients (34 F/11 M) with a mean age of 46.9 years were included. A significant increase in total gastric reservoir volume (124.8 +/- 58.7 and 188.6 +/- 76.4 mL at 1 and 12 months, respectively; p = 0.001) was observed. No statistically significant differences were observed comparing volume of the two components at the two time points. The %EWL at 18 months was inversely correlated with reservoir volume changes at 12 months after LSG (p = 0.006). We describe an easy volumetric model to estimate the size of the gastric reservoir after LSG. Moreover, a direct relationship between an increase in gastric reservoir volume and a lower weight loss after surgery was documented.