Physical principles of available adjustable gastric bands: how they work

Commonly used adjustable gastric bands function on two different physical principles: low pressure-high volume and high pressure-low volume system.

A study was carried out to investigate the theoretical and clinical levels of adjustable band volume-pressure features and their possible influence on band-related complications. The theoretical study had two objectives: to define physical principles of impact of the band balloon on the gastric wall at the stoma region, and to apply a physical formula for calculating this data. The objectives of the clinical part of the study were to construct a simple reliable measuring device, enabling data collection on an out-patient basis from patients who had undergone gastric banding with the two band systems, to support or refute the theoretically calculated results.

A physical formula calculated the pressure applied by the different band systems on the gastric wall in the stoma region. Calculations revealed a >100% difference in pressure caused by the respective bands. Invasive pressure measurements in 35 patients with the different balloon systems agreed with the calculated data, and found a >100% difference in pressure affecting the stoma wall both at rest and during meals.

Differences in pressure on the gastric wall related to the physical system on which the bands operate may be a partial explanation for long-term complications of respective bands.