Mixed coil catheter and process for making same
A mixed coil catheter includes a hollow inner liner defining a lumen, having an exterior surface, and defining a middle point, a single support cord coiled around the exterior surface of the inner liner starting from an intermediate point in a distal direction up to a support end plane and then reversed in the proximal direction proximally away from the support end plane at least past the middle point of the inner liner, having a maximum outer diameter, and forming an end wall at the support end plane, and an outer liner covering the inner liner and the support cord to fix the support cord in place.
1. A mixed coil catheter, comprising:
a hollow inner liner defining a lumen and having an exterior surface;
a single support cord:
coiled around the exterior surface of the inner liner starting from an intermediate point of the inner liner in a distal direction up to a support end plane and then reversed in a proximal direction proximally away from the support end plane at least past the intermediate point of the inner liner, the support cord being in direct contact with the exterior surface of the inner liner at the intermediate point;
having a maximum outer diameter, and
forming an end wall at the support end plane; and
an outer liner covering the inner liner and the support cord to fix the support cord in place.
2. The catheter according to claim 1 , which further comprises a distal marker band having a proximal side and a band outer diameter, the marker band disposed about the inner liner to place the proximal side adjacent the end wall, the outer liner covering the marker band to fix the support cord and the marker band in place such that the band outer diameter is no greater than the maximum outer diameter of the support cord.
3. The catheter according to claim 1 , wherein the inner liner is an extrusion of at least one of ethylene chlorotrifluoroethylene, EFEP, ethylene tetrafluoroethylene, fluorinated ethylene propylene, liquid crystal polymer, nylon, polyethylene, polyether ether ketone, polyethylene terephthalate, perfluoroalkoxy, polytetrafluoroethylene, polyvinylidene fluoride, and tetrafluoroethylene hexafluoropropylene vinylidene fluoride.
4. The catheter according to claim 3 , wherein the inner liner has a wall thickness of between approximately 0.0127 mm and approximately 2.54 mm.
5. The catheter according to claim 3 , wherein the inner liner is approximately 0.00075″ thick.
6. The catheter according to claim 1 , wherein the support cord is a flat stainless steel wire having a cross-sectional dimension of approximately 0.51 mm by approximately 0.2 mm.
7. The catheter according to claim 1 , wherein the support cord is a flat wire having a thickness in a range of between approximately 0.0051 mm to 25.4 mm and a width in a range of between approximately 0.0508 mm to 25.4 mm.
8. The catheter according to claim 1 , wherein the support cord is a round wire having a thickness in a range of between approximately 0.0127 mm to 12.7 mm.
9. The catheter according to claim 1 , wherein the support cord is made of a material of at least one of a stainless steel alloy, a titanium alloy, a nickel alloy, a cobalt alloy, a nitinol alloy, a copper clad aluminum, a stainless clad copper, and tungsten.
10. A method for manufacturing the mixed coil catheter of claim 1 , which comprises:
placing the inner liner onto a mandrel, the inner liner defining a proximal end, a distal end, and a middle point;
loading the mandrel with the inner liner into a coil winder having a proximal connector adjacent the proximal end;
applying tension to the mandrel;
temporarily securing a first end of the single support cord one of:
adjacent the proximal connector; and
to the proximal connector;
spinning the mandrel in a first direction to wind the support cord about the inner liner over a first portion at a first pitch;
at an intermediate point, continuing to wind the support cord about the inner liner over a second portion at a second pitch to create a pitch transition;
reversing the mandrel in a second direction opposite the first direction and continuing to wind the support cord at the second pitch the support cord forming the end wall along the support end plane orthogonal to an axis of the mandrel, the end wall facing the distal end of the inner liner and having a given outer diameter;
continuing to rotate the mandrel in the second direction until the support cord is adjacent the pitch transition and creates a last-crossed position:
while keeping tension on the support cord, the securement of the first end is removed to loosen a proximal length of the support cord from the first end to the last-crossed position as a loose wire:
trimming the loose wire from the inner liner adjacent the last-crossed position;
continuing to rotate the mandrel in the second direction to wind the support cord at a third pitch in the proximal direction past the last-crossed position to an endpoint that is proximal of the middle point of the inner liner;
cutting the support cord at the endpoint to create a second end and securing the second end to the inner liner at the endpoint;
sliding a marker band having an outer diameter equal to or less than the given outer diameter over the distal end of the inner liner to place a proximal side of the marker band against the end wall;
sealing an exterior of the inner liner, the support cord, and the marker band with a coating as the outer liner to fix the support cord and the marker band tin place such that the outer diameter of
the marker band is no greater than the maximum outer diameter of the support cord wrapped around the inner liner; and
removing the inner liner, the support cord, the marker band, and the outer liner from the mandrel to form a mixed coil catheter.
11. The method according to claim 10 , wherein the securing of the first end is performed with an adhesive.
12. The method according to claim 10 , wherein the first pitch is in a range of between approximately 0.0127 mm to 25.4 mm.
13. The method according to claim 10 , wherein the second pitch is approximately 0.66 mm.
14. The method according to claim 10 , wherein the reversing step is carried out by wrapping the support cord completely around the inner liner along the support end plane to form the end wall.
15. The method according to claim 10 , wherein the third pitch is the same as the second pitch.
16. The method according to claim 10 , wherein the third pitch is different from the second pitch.
17. A mixed coil catheter, comprising:
a hollow inner liner defining a lumen and having an exterior surface;
a single support cord:
coiled around the exterior surface of the inner liner starting from an intermediate point in a distal direction up to a support end plane and then reversed in a proximal direction proximally away from the support end plane at least past the intermediate point, the support cord being in direct contact with the exterior surface of the inner liner at the intermediate point;
having a maximum outer diameter; and
forming an end wall at the support end plane;
a distal marker band having a proximal side and a band outer diameter, the marker band disposed about the inner liner to place the proximal side adjacent the end wall; and
an outer liner covering the inner liner, the support cord and the marker band to fix the support cord and the marker band in place such that the band outer diameter is no greater than the maximum outer diameter of the support cord.
18. The catheter according to claim 17 , wherein the inner liner is an extrusion of at least one of ethylene chlorotrifluoroethylene, EFEP, ethylene tetrafluoroethylene, fluorinated ethylene propylene, liquid crystal polymer, nylon, polyethylene, polyether ether ketone, polyethylene terephthalate, perfluoroalkoxy, polytetrafluoroethylene, polyvinylidene fluoride, and tetrafluoroethylene hexafluoropropylene vinylidene fluoride.
19. The catheter according to claim 18 , wherein the inner liner has a wall thickness of between approximately 0.0127 mm and approximately 2.54 mm.
20. The catheter according to claim 18 , wherein the inner liner is approximately 0.00075″ thick.
21. The catheter according to claim 17 , wherein the support cord is a flat stainless steel wire having a cross-sectional dimension of approximately 0.51 mm by approximately 0.2 mm.
22. The catheter according to claim 17 , wherein the support cord is a flat wire having a thickness in a range of between approximately 0.0051 mm to 25.4 mm and a width in a range of between approximately 0.0508 mm to 25.4 mm.
23. The catheter according to claim 17 , wherein the support cord is a round wire having a thickness in a range of between approximately 0.0127 mm to 12.7 mm.
24. The catheter according to claim 17 , wherein the support cord is made of a material of at least one of a stainless steel alloy, a titanium alloy, a nickel alloy, a cobalt alloy, a nitinol alloy, a copper clad aluminum, a stainless clad copper, and tungsten.