Development of an Anisotropic Hyperelastic Material Model for Porcine Colorectal Tissues

Area of Science:

• Biomedical Engineering
• Materials Science
• Surgical Research

Background:

• Colorectal anastomotic leaks are life-threatening complications affecting thousands annually.
• Mechanical interactions between surgical staples and tissues are implicated in anastomotic leakage.
• Limited and inconsistent experimental data on colorectal tissue mechanics hinder understanding of failure mechanisms.

Purpose of the Study:

• To develop an anisotropic hyperelastic material model for colorectal tissues.
• To characterize the mechanical behavior of colorectal tissue for improved anastomotic simulations.
• To provide a reliable computational model for simulating colorectal surgeries.

Main Methods:

• Uniaxial testing of freshly harvested porcine colorectal specimens.
• Specimen extraction along circumferential and longitudinal orientations from age- and weight-matched pigs.
• Development of a constitutive model combining Yeoh hyperelasticity with directional fibers.

Main Results:

• An anisotropic hyperelastic material model was successfully developed for colorectal tissues.
• The model accurately captured the tissue's mechanical behavior (R² values of 0.9968 and 0.9675).
• Coefficients for the constitutive model were precisely determined from experimental data.

Conclusions:

• The proposed anisotropic hyperelastic model reliably simulates colorectal tissue behavior.
• This model can be integrated into finite element analysis for simulating colorectal anastomoses.
• Improved understanding and simulation of tissue mechanics can enhance surgical outcomes and reduce anastomotic leaks.