The inaccuracy of the endoscopic anastomotic measurement techniques

Background: Roux-en-Y gastric bypass (RYGB) is a reliable treatment for obesity, and most of the people do lose weight after the surgery. However, there are risks for the failure to lose weight or weight regain. One of the primary reasons for weight regain after the RYGB is the size of the anastomosis at the gastrojejunostomy (GJ). There is no standard endoscopic technique for the measurement of this anastomosis. Consequently, many treatment plans may lead to ineffective intervention. This study was performed to identify the most accurate method to measure the luminal diameter of GJ endoscopically. This may allow better management of the patients with weight regain after the RYGB. Methods: Ten subjects were asked to endoscopically measure a ring of known diameter at the end of a plastic tube representing the esophagus using four commonly used endoscopic measuring techniques and a double channel endoscope. Subjects used (I) visual estimation (VE); (II) instrument reference (IR) to biopsy forceps; (III) esophageal dilating balloon (EDB); (IV) ruler made from an endoscopic retrograde cholangiopancreatography (ERCP) guide wire tip. The five models were presented in random order. The data was collected and saved in the institutional database. Results: A total of 10 participants, 9 surgeons and 1 gastroenterologist, participated in the study. Endoscopic experience was >1,000 scopes for 4 subjects; 250-500 for 3, and <100 for 3. The VE was the least accurate with an average diversion (AD) from the actual diameter of 6.25 +/- 4.95 mm (24.2%); followed by IR, 3.89 +/- 3.05 mm (14.8%); then the ruler, 2.4 +/- 1.9 mm (9.2%). The balloon measurement was the most accurate, with AD of 1.46 +/- 0.9 mm (7.2%). Of the 200 total measurements, 8 (4%) were accurate, 142 (71%) were underestimating, and 50 (25%) were overestimating. Underestimation was found in 82.5% (33/40) of each of the VE and IR methods; while it was less in the ruler method 60% (24/40); and least in the balloon method 40% (16/40). Additionally, the overestimation was highest in balloon method 55% (22/40), followed by ruler method 35% (14/40), then IR 15% (6/40); and lowest in VE 12.5% (5/40). Measurements of the largest model diameter (33 mm) were 98% underestimating; while only 2% were overestimating. In the smallest diameter model (13 mm), 16% of the measurements were underestimating; 2% were accurate, and 82% were overestimating. Conclusions: Endoscopic VE of anastomosis diameter is the least accurate method of measurement leading to the overestimation of the measurements. It is, therefore, highly recommended that endoscopists avoid using only VE entirely for the measurement of GJ. More objective methods may be considered for the measurement of GJ diameter.