Changes in oesophageal wall biomechanics after portal vein banding and variceal sclerotherapy measured by a new technique. An experimental study in rabbits.

The biomechanical properties of the oesophageal wall were investigated in a rabbit model using a four electrode impedance technique. A specially designed probe with the electrodes inside a low pressure expandable insulating latex balloon was introduced in the oesophagus. Stepwise inflation and deflation was done for analysis of oesophageal compliance and hysteresis. The rabbits were allocated to three groups: a control group, one with oesophageal varices and one with varices which were treated by sclerotherapy. The oesophageal varices were induced by portal banding five months before the investigation. A uniform pattern of changes in the biomechanical properties of the oesophageal wall was seen in the group with oesophageal varices when compared with controls. The compliance was significantly decreased, and the hysteresis was lessened. Endoscopic sclerotherapy changed the wall properties to a pattern not distinguishable from normal. Thus, in vivo investigation of the biomechanical wall properties showed a significant loss of distensibility of the oesophagus with varices and restorement of the wall distensibility when the varices were treated with endoscopic sclerotherapy.