Date of Award
Doctor of Philosophy (PhD)
Burg, Karen J.L.
Nagatomi , Jiro
Webb , Ken
Current meshes used for soft-tissue repair are mostly composed of single component, nonabsorbable yarn constructions, limiting the ability to modulate their properties. This situation has left the majority of soft tissue repair load-bearing applications to suffer distinctly from undesirable features associated, in part, with mesh inability to (1) possess short-term stiffness to facilitate tissue stability during the development of wound strength; (2) gradually transfer the perceived mechanical load as the wound builds mechanical integrity; and (3) provide compliance with load transfer to the remodeling and maturing mesh/tissue complex. The likelihood of long-term complications is reduced for fully absorbable systems with degradation and absorption at the conclusion of their intended functional performance.
The primary goal of this dissertation was to develop and characterize a fully absorbable bicomponent mesh (ABM) for hernia repair which can modulate biomechanical and physical properties to work with the expected needs of the wound healing process. The first study reviewed the current state of hernioplasty and proposed the subject device. The second study investigated different knitting technologies to establish a mesh construction which temporally modulated properties. To this end, a novel construction using warp knitting was developed where two degradable copolyester yarns with different degradation profiles were coknit into an initially interdependent knit construction. The developed knit construction provided an initial high level of structural stiffness; however, upon degradation of the fast-degrading yarn the mesh comprised of the slow-degrading yarn was liberated and affords high compliance. In the third study, the segmented, triaxial, high-glycolide copolyester used as the fast-degrading yarn was optimized to retain strength for greater than 18 days. As such, the ABM physical and biomechanical transition was designed to temporally coincide with the expected commencement of wound strength.
The fourth study investigated the in vivo tissue response and integration of the developed degradable copolyester yarns in a novel construct to simulate the ABM. Results indicated a strong initial inflammatory response which resolved quickly and an integration process that produced a dense, compacted, and oriented collagen capsule around the implant during the transition phase. For the final study, the clinically-relevant biomechanical properties of two different ABM constructions were compared against traditional hernia meshes. Using a novel synthetic in vitro simulated mesh/tissue complex, the ABM were found to provide significantly greater early stability, subsequent biomechanics that approximated that of the abdominal wall, and evidence of restoring endogenous tension to the surrounding tissue. These results were in marked contrast to traditional hernia meshes which showed stress shielding and significantly greater stiffness than the abdominal wall.
Peniston, Shawn, "Modulated Properties of Fully Absorbable Bicomponent Meshes" (2010). All Dissertations. 647.