Absorbable Triphasic Hernial Meshes

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DESCRIPTION (provided by applicant): Hernial repair is the most frequent operation in general surgery for which synthetic meshes are commonly used in repairing abdominal defects. Frequently used meshes consist of non-absorbable polymers such as polypropylene, polyethylene terephthalate, or polytetrafluoroethylene. Recently established modifications of these meshes to improve them biomechanical compatibility and the healing process include combination with absorbable glycolide copolyesters or polydioxane. However, the non-absorbable meshes and their combinations with absorbable components do suffer distinctly from undesirable features associated, in part, with their inability to (1) allow gradual load transfer to healing tissues to assist in accelerating wound- healing; (2) prevent or minimize adhesion formation at the surgical site due to their practically bioinert surfaces; (3) display, incrementally, decreasing modulus to accommodate, favorably, the biomechanics of healing surgical sites; and (4) prevent or minimize the likelihood of extrusion and incidents of infection following the conclusion of their intended functional performance. Such inadequacy prompted contemporary surgeons and bioengineers to stress the need for new meshes capable of providing (1) an initially high burst strength and stiffness (or flexural modulus); (2) measurable holding/bursting strength for at least eight weeks-this is clinically relevant to hernial repair of compromised tissue wounds as in geriatric patients; (3) incrementally decreasing holding/bursting strength during and shortly after the tissue healing to transfer the load, gradually, to surrounding tissues-this is to aid the healing process and formation of strong, organized new tissues; (4) dynamically regenerating bioactive surfaces to minimize the incidence of infection and adhesion formation; and (5) exhibit mass loss profiles leading to practically total mass loss at the surgical site. This provided the incentive to pursue the proposed Phase I study. Accordingly, Phase I objective is to determine the feasibility of developing absorbable triphasic hernial meshes comprising two different fibrous components and a coating to provide, incrementally, changing biomechanical profiles and biochemically compatible tissue-interfacing surfaces during and following the critical healing process. And Phase I plans entail (1) synthesis, characterization and conversion to multifilament yarn of relatively fast- and slow-absorbing polymers; (2) construction of the two yarns into warp-knitted mesh candidates; (3) synthesis and characterization of an absorbable, nitrogenous copolyester and its use to coat the candidate meshes; (4) sterilization of coated meshes and in vitro evaluation of their initial mechanical properties and effect of incubation in degrading environments; and (5) completion of a limited animal study on selected candidates and identification of two most promising meshes for use in planning Phase II study. This will entail comprehensive in vitro and in vivo evaluation, selection of a final and back-up candidates, completion of polymer and mesh development, and scale-up studies and initiation of preclinical studies. PUBLIC HEALTH RELEVANCE: Development of a novel triphasic, absorbable mesh, exhibiting a three-step mass loss profile for hernial repair, using a relatively fast- and slow-absorbing multifilament yarn constructed in a new warp-knitted form and coated with a fast-absorbing, lubricious absorbable polyester, will provide the surgeon with an exceptionally effective tool for repairing different forms of hernia without contending with the established clinical drawbacks of single-component, non-absorbable, and bicomponent, partially absorbable commercial meshes.