Temporarily Stiffened Mesh Prostheses

Abstract

The present invention relates to medical prostheses and methods of manufacturing those devices. In particular, the prostheses are temporarily stiffened meshes with particular coatings to provide initial stiffness and thereby permit easier surgical handling for treatment or reconstruction of soft tissue defects. Preferred embodiments include surgical meshes coated with one or more biodegradable polymers that can act as a stiffening agent by coating the filaments or fibers of the mesh to temporarily immobilize the contact points of those filaments or fibers and / or by increasing the stiffness of the mesh by at least 1.1 times its original stiffness. The devices of the invention can also provide relief from various post-operative complications associated with their implantation, insertion or surgical use. By including biologically active agents and / or drugs in the coating, the devices provide prophylaxis for and can alleviate side effects or complications associated with the surgery or use of prostheses in general.

Description

[0001]This application is a continuation of U.S. Ser. No. 11 / 672,929, filed Feb. 8, 2007, which claims priority under 35 U.S.C. § 119(e)(5) of U.S. Provisional Patent Application No. 60 / 864,597, filed Nov. 6, 2006 and U.S. Provisional Patent Application No. 60 / 772,827, filed Feb. 8, 2006, which are incorporated herein by reference.FIELD OF THE INVENTION[0002]The present invention relates to medical prostheses and methods of manufacturing those devices. In particular, the prostheses are temporarily stiffened meshes with particular coatings to provide initial stiffness and thereby permit easier surgical handling for treatment or reconstruction of soft tissue defects. Preferred embodiments include surgical meshes coated with one or more biodegradable polymers that can act as a stiffening agent by coating the filaments or fibers of the mesh to temporarily immobilize the contact points of those filaments or fibers and / or by increasing the stiffness of the mesh by at least 1.1 times its o...

AI Technical Summary

Benefits of technology

[0016]The coated meshes of the invention are capable of releasing one or more drugs into surrounding bodily tissue such that the drug reduces or prevents an implant- or surgery-related complication. For example, the surgical mesh coatings can include an anesthetic agent such that agent seeps into the surrounding bodily tissue, bodily fluid, or systemic fluid in a predictable manner and at rate sufficient to attenuate the pain experienced at the site of implantation. In another example, the surgical meshes coatings can include an anti-inflammatory agent such that the anti-inflammatory agent seeps into the surrounding bodily tissue, bodily fluid or systemic fluid in a predictable manner and at a rate sufficient to reduce the swelling and inflammation associated implantation of the mesh. Still a further example, the surgical mesh coatings can include an antimicrobial agent such that the antimicrobial agent is released into the surrounding bodily tissue, bodily fluid, or systemic fluid in a predictable manner and at a therapeutically-effective dose to provide a rate of drug release sufficient to prevent colonization of the mesh (and / or surgical implantation site) by bacteria for a minimum of the period of time following surgery necessary for initial healing of the surgical incision.

Problems solved by technology

However, such devices are often associated with post-surgical complications including post-implant infection, pain, excessive scar tissue formation and shrinkage of the prosthesis or mesh.

Patients will occasionally be given systemic antibiotics prophylactically; however, literature review of clinical trials does not indicate that systemic antibiotics are effective at preventing implant-related infections.

Hernias usually occur because of a natural weakness in the abdominal wall or from excessive strain on the abdominal wall, such as the strain from heavy lifting, substantial weight gain, persistent coughing, or difficulty with bowel movements or urination.

Tightly woven meshes with the highest strength characteristics and stiffness are very easy for the surgeon to implant; however, there appears to be a positive correlation between the tightness of the weave (correlated to surface area and stiffness), lack of patient mobility, and chronic pain.

Newer meshes have larger pore structures and while they are more flexible, they are also more difficult to implant by surgeons.

They are extremely difficult for laparoscopic repair, as they have very little recoil associated with them and, when rolled up to insert, they cannot be reflattened and positioned in a quick and efficient manner by the surgeon.

Surgical meshes that have been manipulated to improve handling, insertion and positioning post-insertion are known in the art, but do not employ larger-pore mesh construction.

For example, a laparoscopic surgical mesh with extruded monofilament PET coils or rings (e.g., the Bard® Composix® Kugel® hernia patch) increases the overall stiffness of the device and gives a shape memory to the device but does not readily allow for drug loading of the mesh, can not provide temporary stiffening of the mesh component, and can not be further shaped into a fixed three-dimensional structure after manufacture without further processing or alteration.

These meshes have the same disadvantages as those with coils or rings.

Additionally, the Kugel patch ring has been reported to break under conditions of use, causing patient morbidity and mortality.

Moreover, because the biodegradable polymers of that mesh may be subjected to high temperatures to produce fibers and filaments suitable for weaving, it drastically limits the drugs or biologically active agents that can be included in a biodegradable layer since, under such conditions, the vast majority of biologically-active agents and drugs are unable to withstand the manufacturing temperatures involved in fiber and filament formation.

Finally, these meshes are often more difficult for surgeons to anchor in place because the polyglactin fiber cannot withstand the suturing tension.

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