Elastic properties of the isolated perfused porcine duodenum.

The aim was to investigate elastic wall properties of the isolated perfused porcine duodenum using manometry and impedance planimetry. Distension of an intraluminal balloon with definite pressure steps of 0.5, 1.0, 2.0, 3.0 and 5.0 kPa was done with simultaneous recording of balloon pressure and balloon cross-sectional area (Bcsa). Wall thickness of the relaxed intestine was estimated from measurement of tissue density. The elastic wall parameters were calculated from these measurements. Balloon inflation elicited a phase of rapid Bcsa increase followed by an accommodation phase of slow Bcsa increase. At steady state, the circumferential and the radial wall stress increased as linear functions of the applied balloon pressure, while the circumferential and the radial wall strain increased nonlinearly. The incremental elastic moduli increased exponentially. Our model allows the study of passive biomechanical wall properties of the intact duodenum. The duodenal wall showed qualitatively and also quantitatively an elastic nature.