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

Background 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. Methods 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. Results 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). Conclusions 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.