Pathophysiology of Laparoscopic Adjustable Gastric Bands: Analysis and Classification Using High-Resolution Video Manometry and a Stress Barium Protocol

Symmetrical pouch dilatation has become the most common problem following laparoscopic adjustable gastric banding (LAGB). Although, in a significant number of symptomatic patients, no explanation for the underlying problem is identified with a contrast swallow. There is a need for a better understanding of the pathophysiology of LAGBs and more sensitive diagnostic tests. LAGB patients with adverse symptoms or poor weight loss (symptomatic patients), in whom a contrast swallow had not shown an abnormality, underwent high-resolution video manometry. This incorporated a semi-solid, stress barium, swallow protocol. Outcomes were categorized based on anatomical appearance, transit through the LAGB, and esophageal motility. Cohorts of successful (> 50% excess weight loss with no adverse symptoms) and pre-operative patients were used as controls. One hundred twenty-three symptomatic patients participated along with 30 successful and 56 pre-operative patients. Five pathophysiological patterns were defined: transhiatal enlargement (n = 40), sub-diaphragmatic enlargement (n = 39), no abnormality (n = 30), aperistaltic esophagus (n = 7), and intermittent gastric prolapse (n = 3). Esophageal motility disorders were more common in symptomatic and pre-operative patients than in successful patients (p = 0.01). Differences between successful and symptomatic patients were identified in terms of the length of the high-pressure zone above the LAGB (p < 0.005), peristaltic velocity (p < 0.005), frequency of previous surgery(p = 0.01), and lower esophageal sphincter tone (p = 0.05). Video manometry identified abnormalities in three quarters of symptomatic patients where conventional contrast swallow had not been diagnostic. Five primary patterns of pathophysiology were defined. These were used to develop a seven category, clinical, classification system based on the anatomical appearance at stress barium. This system stratifies the spectrum of symmetrical pouch dilatation and can be used to logically guide treatment.