Hernia repair is one of the most frequently performed surgical operations in the United States with approximately 800,000 procedures performed annually. The vast majority of these repairs employ a "tension- free" repair technique which involves the use of synthetic surgical meshes. Existing mesh technology is designed to be of high strength to produce a perceived robust repair. However, these meshes are unable to respond to the dynamic biological needs of the wound healing process. Mesh contraction, increased rigidity over time, entrapment of sensory nerves, and chronic inflammatory responses to the prosthesis, among other mesh-related factors, contribute to long-term complications such as chronic pain, increased abdominal wall stiffness and fibrosis. Therefore, the overall goal of this project is to create a novel surgical mesh that modulates its biomechanical properties in vivo based on the dynamic needs of the wound healing process resulting in a reduction of long-term complications to the patient. Whereas the most glaring problem in existing surgical meshes is structural rigidity for the life-time of the patient, the selectively absorbable mesh being developed in this Phase I study will ultimately transfer load back to the native tissue through increased prosthetic extensibility over time, highlighting the most innovative feature of the proposed device. The final outcome (increased extensibility to mirror the extensibility of the native abdominal wall at the end of the wound healing process) is unlike that currently seen with existing non-absorbable and partially absorbable surgical mesh technology (a terminally rigid prosthesis). Accordingly, the research strategy employed in this study is as follows.
In Specific Aim 1 various selectively absorbable bi-component mesh constructions will be developed, each possessing a unique in vivo extensional profile. This will require the development of various absorbable fiber components and the use of a novel warp-knitting construction where upon the non-absorbable fiber is knit to be held in tension by the absorbable fiber. Upon significant strength loss of the absorbable fiber, the non-absorbable component is "released" resulting in increased mesh extensibility.
In Specific Aim 2 this suite of meshes will be used as a tool to evaluate the effect of mechanical load transitioning back onto the native tissue through the use of a clinically-relevant animal model that simulates the wound pathology associated with mature hernia development in humans. Key indicators for success include evaluation of the overall foreign- body response, mesh repair site mobility, mesh contracture, and incidence of hernia recurrence as compared to existing predicate materials. A high-degree of success is expected with this bioengineering approach to achieving mesh biocompatibility, culminating in the development of a novel surgical mesh that improves the clinical outcomes of hernia repair.
Existing surgical meshes currently used in hernia repair are still based upon the same terminally rigid mesh design that was first introduced in clinical practice over 30 years ago. Common long-term complications such as reduced abdominal wall mobility, chronic pain, and hernia recurrence can be linked to the use of these devices, indicating a need for new mesh designs exhibiting improved mesh biocompatibility. The goal of this project is to create a novel selectively absorbable surgical mesh that mirrors the changing needs of the native abdominal wall tissue, moving from initial rigidity to increased extensibility allowing for the transfer of load back onto the healing abdominal wall;thus, reducing long-term complications and improving patient outcomes.