Variable stiffness multilayer catheter tubing

Abstract

A catheter body having a variable stiffness along its longitudinal length and a method for manufacturing same is disclosed wherein an inner layer having an uninterrupted length serves as a backbone for segments of coextrusion of, e.g., Pebax or nylon and a tie layer which are then bonded to the backbone to create a multi-stiffness catheter body.

1 - 29 . (canceled) 
     
     
         30 . A catheter tubing having a variable stiffness, comprising:
 a length of a multi-layer extrusion to serve as a backbone for the catheter tubing, the multi-layer extrusion having an outer layer and an inner layer;   removing a portion of the outer layer from a distal end of said multi-layer extrusion to an intermediate location to expose the inner layer;   a first extrusion segment having a stiffness that differs from that of the outer layer of the multi-layer extrusion is placed over the exposed inner layer until the first extrusion segment abuts the outer layer of the multi-layer extrusion at the intermediate location; and   permanently attaching the abutting extrusion segment to the multi-layer extrusion by melt bonding.   
     
     
         31 . The catheter tubing with a variable stiffness of  claim 30 , wherein a second extrusion segment having a stiffness that differs from that of the first extrusion segment is positioned over the exposed inner layer of the multi-layer extrusion until it abuts the first extrusion segment. 
     
     
         32 . The catheter tubing with a variable stiffness of  claim 31 , wherein the abutting portion of the first extrusion segment and the second extrusion segment is melt bonded. 
     
     
         33 . The catheter tubing with a variable stiffness of  claim 32 , wherein the second extrusion segment comprises a tungsten-filled polymer extrusion. 
     
     
         34 . The catheter tubing with a variable stiffness of  claim 32 , wherein the inner layer is formed of HDPE. 
     
     
         35 . The catheter tubing with a variable stiffness of  claim 32 , wherein the inner layer is formed of UHMWPE. 
     
     
         36 . The catheter tubing with a variable stiffness of  claim 32 , wherein the outer layer is comprised of one of the group of nylon and Pebax. 
     
     
         37 . The catheter tubing with a variable stiffness of  claim 31 , wherein an outer layer of the first extrusion segment and the outer layer of the multi-layer extrusion overlap to form a transition region. 
     
     
         38 . The catheter tubing with a variable stiffness of  claim 37 , wherein the overlapping portions of the first extrusion segment and multi-layer extrusion are angle-cut to feather the transition region. 
     
     
         39 . The catheter tubing with a variable stiffness of  claim 38 , wherein the overlapping portions include flaps trimmed to differing lengths to broaden the transition region. 
     
     
         40 . The catheter tubing with a variable stiffness of  claim 31 , wherein the first extrusion segment includes an inner tie layer to bond with the inner layer of the multi-layer extrusion. 
     
     
         41 . The catheter tubing with a variable stiffness of  claim 40 , wherein the inner layer of the multi-layer extrusion is a fluoropolymer.