Method of forming an implantable device
An implantable structure, method for making the structure and method for using the structure, where the structure includes a combination of non-absorbable and absorbable components, and the implantable structure has a randomly uniform array of materials. The resulting implantable structure provides improved tissue ingrowth and flexibility after implantation and after absorption of the absorbable materials.
1. A method of forming an implantable device, comprising the steps of:
a. Forming a first yarn and a second yarn, wherein at least one of said first yarn and second yarns includes a first non-absorbable filament and at least one of said first yarn and second yarns includes a first absorbable filament, said first absorbable filament having a lower melting point than said first non-absorbable filament, and including the step of kinking at least one of said first absorbable filament and said first non-absorbable filament prior to forming said first or second yarn;
b. Forming an initial woven structure comprising said first yarn and second yarn;
c. Subjecting said initial woven structure to a first heat treatment at a first temperature sufficient to cause shrinkage of said first absorbable filament, and thus buckling at least the second yarn and forming an initial heated structure;
d. Heating said initial heated structure to a second temperature, said second temperature being higher than said first temperature, wherein at least a portion of said first absorbable filament is melted; and
e. Allowing said heated structure to cool to form a resulting implantable device.
2. The method of claim 1 , further comprising the step of compressing said initial woven structure during said step of heating said initial heated structure at a second temperature.
3. The method of claim 1 , wherein said first yarn comprises a first non-absorbable filament and a first absorbable filament, and said second yarn comprises a second non-absorbable filament and a second absorbable filament.
4. The method of claim 3 , wherein said first absorbable filament is polydioxanone and said first non-absorbable filament is polypropylene.
5. The method of claim 1 , wherein said first yarn comprises a first non-absorbable filament, a first absorbable filament and a second absorbable filament, and said second yarn comprises a second non-absorbable filament and a third absorbable filament.
6. The method of claim 5 , wherein said first absorbable filament is polyglactin, said second absorbable filament is polydioxanone, and said first non-absorbable filament is polypropylene.
7. The method of claim 1 , wherein said resulting implantable device has a thickness of about 0.1-2 mm after said step of cooling.
8. The method of claim 1 , wherein said step of subjecting said initial woven structure to a first heat treatment comprises placing said initial woven structure in a heating source having a gap that is at least as wide as said thickness of said initial woven structure.
9. The method of claim 1 , wherein said step of subjecting said initial woven structure to a first heat treatment comprises subjecting said initial woven structure to a first temperature that is about 0.1 to about 2° C. less than the melting point of the absorbable filament having the lowest melting point in said initial woven structure.
10. The method of claim 1 , wherein said second temperature is a temperature that is about 0.1° C. to about 20° C. greater than the melting point of the absorbable filament having the lowest melting point in said initial woven structure.