Why Size Matters: an Evaluation of Gastric Pouch Size in Roux-en-Y Gastric Bypass Using CT Volumetric Analysis and its Effect on Marginal Ulceration

Abstract

Marginal ulceration (MU) is a common long-term complication following Roux-en-Y gastric bypass (RYGB). The causes of MU after RYGB are multifactorial and include surgical technique of constructing the gastrojejunal anastomosis (GJA). The purpose of this study is to evaluate the relationship between gastric pouch size in RYGB and MU using CT volumetrics. Patients were retrospectively identified who underwent esophagogastroduodenoscopy (EGD) following RYGB at a tertiary care teaching hospital. Measurement of gastric pouch size was performed using 3-D CT software. Standard statistical methods were used, a univariate comparison was performed between MU and non-MU patients followed by a propensity-matched comparison to control for factors known to affect MU, and a propensity-matched subgroup analysis was also performed. In total, 122 patients met criteria, 57 of which had MU on EGD and 65 who did not. The MU group had more smokers and patients with PPI use than the non-MU group, and the mean time from operation to CT scan was 26.6months (range: 0-108months). The MU group had a larger gastric pouch size than the non-MU group (34.1 ± 11.8 versus 20.1 ± 6.8 cm3). When analyzed for matched patient cohorts, this difference remained for the MU group that included smokers and PPI use. When stratified for pouch size, for each 5 cm3 increase in pouch size, patients had 2.4 times odds increase of MU formation. CT volumetric analysis demonstrated that a larger gastric pouch size was associated with MU following RYGB.