Rotational spun material covered medical appliances and methods of manufacture
A medical appliance or prosthesis may comprise one or more layers of rotational spun nanofibers, including rotational spun polymers. The rotational spun material may comprise layers including layers of polytetrafluoroethylene (PTFE). Rotational spun nanofiber mats of certain porosities may permit tissue ingrowth into or attachment to the prosthesis. Additionally, one or more cuffs may be configured to allow tissue ingrowth to anchor the prosthesis.
1. A method of constructing a medical appliance, the method comprising:
rotational spinning a first tube of polytetrafluoroethylene (PTFE) onto a mandrel, wherein the PTFE is expelled from a plurality of orifices of a spinneret under centrifugal force and hydrostatic force, wherein the spinneret rotates about an axis of rotation and the plurality of orifices are radially offset from the axis of rotation; and
sintering the first tube.
2. The method of claim 1 , wherein the first tube of PTFE is rotational spun onto a rotating mandrel.
3. The method of claim 2 , wherein the mandrel is positioned substantially orthogonal to an axis of rotation of a rotational spinning spinneret.
4. The method of claim 1 , further comprising applying a second tube of rotational spun PTFE around the first layer.
5. The method of claim 4 , further comprising:
applying a scaffolding structure around the first tube and
applying a fluorinated ethylene propylene (FEP) layer around the first tube and the scaffolding structure, prior to applying the second tube of rotational spun PTFE.
6. The method of claim 5 , further comprising heating the medical appliance such that the FEP layer bonds to the first and second tubes such that the FEP partially bonds to the fibers of the first and second tubes.
7. The method of claim 6 , wherein the FEP flows into and coats the fibers of the first and second tubes while maintaining the porosity of the tubes.
8. The method of claim 4 , wherein the second tube of rotational spun PTFE is formed by a method comprising:
rotational spinning the second tube of PTFE onto a rotating mandrel; and
sintering the second tube.
9. The method of claim 6 , further comprising applying a compressive wrap around the second tube before the medical appliance is heat treated.
10. The method of claim 1 , wherein rotational spinning the first tube of PTFE comprises:
mixing a PTFE dispersion with polyethylene oxide (PEO), wherein the PEO is dissolved in water to form a mixture; and
discharging the mixture from an orifice onto the rotating mandrel.
11. The method of claim 1 , wherein the mandrel comprises a main portion and two leg portions, the main portion configured to coincide with a main lumen of a bifurcated medical appliance and the two leg portions configured to coincide with leg portions of bifurcated medical appliance.
12. The method of claim 11 , wherein the two leg portions of the mandrel are removable from the main portion of the mandrel.
13. The method of claim 11 , wherein the first tube is rotational spun by rotating the mandrel about an axis of the leg portions of the mandrel while rotationally spinning fibers and rotating the mandrel about an axis of the main portion of the mandrel while rotationally spinning fibers.