ANIMAL RESEARCH Evaluation of Gastric Fundus Invagination for Weight Loss in a Porcine Model Elias Darido & D. Wayne Overby & Kim A. Brownley & Timothy M. Farrell Published online: 11 May 2012 # Springer Science + Business Media, LLC 2012 Abstract Gastric fundus compliance allows stomach vol- ume increase in response to food intake. Absence of this postprandial relaxation alters hormonal signals and induces early satiety and weight loss. This study demonstrates the effect of gastric fundus invagination on the growth rate of juvenile pigs. After institutional animal care and use com- mittee approval, 15 juvenile pigs were divided into two groups. In the first group, six pigs were anesthetized, weighed, and submitted to laparotomy, stomach manipula- tion, and short gastric vessel ligation. This is the control group and is referred to as “Sham”. In the second group, gastric fundus invagination was added by using a circular stapler. This is the procedure group and is designated as “GFI”. Postoperatively, body weight and food intake were measured for 5 weeks. Pigs were euthanized and the stom- achs examined. Growth patterns were compared. Three ani- mals were excluded from the analysis. At the end of the 5- week study period, six GFI pigs had intact anastomosis with an invaginated fundus. The mean percent growth rate for the GFI group (54.2±2.8 %) was significantly less than the Sham group (77.7±4.9 %). Gastric fundus invagination significantly decreases the growth rate in juvenile pigs. Keywords Surgical technique . Gastric fundus . Invagination . Weight loss Introduction In 1978, Buchwald and Varco defined metabolic surgery as “the operative manipulation of a normal organ or organ system to achieve a biologic result for a potential health gain” [1]. The operative manipulation of the stomach for weight loss has been guided so far by the traditional concept of restriction [2]. However, central to the success of bariatric procedures are neuro-hormonal changes that decrease appe- tite, increase metabolism, maintain weight loss, and resolve obesity associated comorbidities [3]. This begs the question, does reducing the gastric volume to the smallest pouch possible represent the most effective gastric manipulation for weight loss? The proximal stomach consists of the fundus and part of the gastric body. Receptive relaxation is the reduction in gastric tone and increase in compliance that follows inges- tion of a meal [4]. There is a direct correlation between the degree of impaired postprandial relaxation of the proximal stomach and early satiety [5] and weight loss [6]. Indeed, partial or complete fundoplication used for the treatment of GERD impairs postprandial relaxation and increases the sensation of fullness [7]. In a prospective randomized study, gastric fundoplication was associated with a small but sig- nificant decrease in BMI. Patients were followed for 1 year after surgery and no tendency towards weight regain was noted. There was no association between the decreased BMI and improved quality of life following the procedure [8]. Concomitant with a decrease in stomach wall compliance after reflux surgery, weight and satiety changes may also result from altered neuro-hormonal signaling. In fact, chil- dren with postprandial hypoglycemia, following Nissen fun- doplication, have exaggerated secretion of glucagon-like peptide-1 (GLP-1) [9]. E. Darido (*) : D. W. Overby : K. A. Brownley : T. M. Farrell Department of Surgery CB 7081, UNC Department of Surgery, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7081, USA e-mail: elias721@hotmail.com OBES SURG (2012) 22:1293–1297 DOI 10.1007/s11695-012-0666-4