Date of Award
Master of Science (MS)
It is estimated that 350,000-500,000 ventral hernia repair surgeries are performed each year in the United States. While the long-term recurrence rate of ventral hernia repairs is not yet known, when tissues are exposed to the trauma of surgery, there is always the chance of recurrence. Commonly used ex vivo testing methods for determining the mechanical properties of the abdominal wall and biomaterials for hernia repair consist primarily of uniaxial and biaxial testing, which are not physiologically relevant loading environments. The need for a testing device that can exert physiologically relevant loads ex vivo to an abdominal wall is crucial for the development of more effective repair strategies and products.
After abdominal hernia repairs, coughing poses a major threat to the structural integrity of the repair site. During a cough, the intra-abdominal pressure (IAP) can rise as high as 2.5 psi, compared to the normal IAP of approximately 0.1-0.2 psi. The goal of this project was to design a testing device that can apply and measure a representative coughing force applied to an ex vivo porcine abdominal wall, and develop a strain tracking protocol to track three-dimensional abdominal deformation throughout the duration of the cough.
The constructed device was successful in applying a physiologically relevant force to a porcine abdominal wall, and subsequently decreasing the force back to a normal IAP in less than 2 seconds. The maximum force of the cough can be easily controlled using the Arduino controller, which makes the device robust enough to explore the effects of a range of pressures. By recording a video of the cough using a 3D camera, we were able to successfully track the deformation of the tissue in three-dimensions with an acceptable level of accuracy. The design and validation of this testing method will pave the way for a variety of experiments that will provide greater insight into the mechanical behavior of the abdominal wall and the effectiveness of various repair strategies and products on restoring native tissue function.
Dr. Spencer Lake Dr. Jeffrey Blatnik, MD Dr. Jessica Wagenseil