Understanding the anatomical and functional features of organs, especially the biomechanics of the motility of the digestive tract wall, is essential for accurate diagnosis and therapy.

OBJECTIVE

To analyze the biomechanical features of the stomach wall on the experimental material.

MATERIALS AND METHODS

Based on a literature review about the digestive system of pigs, the parameters of the anisotropic elastic properties of the stomach were calculated both in its various sections and in the layers of the gastric wall that are parallel and perpendicular to the largest curvature of the stomach. The deformation curves of tissue samples were approximated by the function σ = a·(exp(####i/i####·ε) – 1), where a and b are material constants, which were determined using the genfit function of the MATHCAD 13.0 computer algebra system.

RESULTS

Regardless of the layer, the greatest «stiffness» (elastic modulus) of the stomach wall is observed in its body. At the same time, near the fundus and body, the mucosubmucosal layer is the most «rigid» (for the body, 142.47 and 160.43 kPa in the circumferential and longitudinal directions; near the fundus, 68.09 and 78.80, respectively). The «softest» of all was the muscular layer in the fundus of the stomach (46.82 in the circumferential direction and 53.20 kPa in the longitudinal direction). The Young’s modulus in the longitudinal direction was always higher than in the circumferential direction, and the elastic anisotropy coefficient A = Eprod/Eocr was greater than 1 in all cases based on the results of mechanical tensile tests.

CONCLUSIONS

The calculated coefficients of the Mooney-Rivlin hyperelastic model and the polynomial model can be useful in the mathematical modeling of the stress-strain state of the intestinal and gastric wall tissues. Knowledge of the mechanical properties of the gastrointestinal tract can be used in surgery to ensure the efficacy of new anastomosis methods.