Researcher: Samuel Morais
Colaborators: Harsha Ramaraju, Jeehyun Lee, Scott Hollister
Congenital diaphragmatic hernias (CDH) are characterized by weakened or not-fully developed diaphragms, which allows abdominal contents to protrude into the thoracic cavity and affects the development of other organs, such as heart and lungs. Synthetic (Gore-Tex®) and biological (small intestine submucosa – SIS) patches have been clinically used in the last decade for tissue repair. However, high recurrence rates and chest wall deformities have been reported following these procedures. Early diagnosis and assessment of re-herniation after surgical repair is critical to avoid risking adjacent organs.
In this project, we hypothesize that CDH recurrence after prosthetic repair is preceded by fibrosis of surrounding tissue. The buildup of fibrotic tissue will lead to increased diaphragm stiffness that can be detected with Shear Wave Elasticity Imaging (SWEI).
CDH was surgically induced in a rat model through a defect covering approximately 25% of the total diaphragm area. A repair patch was then sutured onto the defect for treatment. The study groups included: 1) a hybrid poly (glycerol dodecanedioate) (PGD) and SIS patch implant, 2) SIS-only implant and 3) control (no implant). SWEI and excursion measurements were performed at 1- and 4-month timepoints after the surgical repair.
The results indicate that even though excursion was higher in the control group, it showed no significant difference between 1-month and 4-months timepoints in the implanted groups. As for the shear modulus, the control group maintained lower shear modulus values, while the SIS group showed a strong increase in shear modulus at 4 months, probably due to fibrosis development in the diaphragm. The SIS+PDG group maintained a stable shear modulus between 1 and 4 months, with no significant difference.
Initial findings suggest that PGD improves diaphragm response to the SIS patch, and this enhancement is more sensitively detected by SWEI than by excursion. The application of SWEI to CDH repair can help studying how early changes in muscle elasticity relates to hernia recurrence.