Process for creating an ingrowth preventing indwelling catheter assembly

Abstract

A surgically implantable delivery or drainage catheter assembly includes a porous fiber membrane that is permeable to the intended drainage or delivery fluid, yet has an outer surface morphology and porosity that prevents the ingrowth of tissue. The porous fiber membrane is created using a phase-inversion process which is controlled to select a desired porosity. A reinforcement member is also disposed within the porous fiber membrane.

1 . A process for making an ingrowth preventing indwelling catheter assembly, the ingrowth preventing indwelling catheter assembly having a distal end configured to be placed within a brain ventricle for drainage of cerebrospinal fluid, the process comprising the steps of:
 providing a length of non-porous flexible tubing having an end;   providing a non-porous tip;   providing a length of porous tubular fiber membrane having a first end and a second end, said porous tubular fiber membrane being permeable to drainage or delivery of fluid but impermeable to tissue ingrowth;   placing a reinforcement member within the porous tubular fiber membrane, said reinforcement member having a first end and a second end;   attaching said first end of the porous tubular fiber membrane and said first end of said reinforcement member to said end of said length of non-porous and flexible tubing; and   attaching said second end of the porous tubular fiber membrane and said second end of said reinforcement member to said non-porous tip.   
     
     
         2 . The process of  claim 1 , wherein said step of providing said length of porous tubular fiber membrane comprises forming said porous tubular fiber membrane by a phase-inversion process. 
     
     
         3 . The process of  claim 2 , wherein the phase-inversion process comprises the steps of dissolving a polymer in a first solution, passing the first solution containing the dissolved polymer through an aperture into a coagulation bath chamber filled with a second solution in which the polymer is non-soluble to create a hollow fiber membrane tube. 
     
     
         4 . The process of  claim 3  wherein the polymer comprises polyether sulfone. 
     
     
         5 . The process of  claim 3 , including the step of controlling at least one of: the concentration of the polymer in the first solution, the flow of the first solution into the chamber of second solution, or temperature, to create a hollow fiber membrane tube having a porosity of less than 5 micrometers. 
     
     
         6 . The process of  claim 3 , wherein the concentration of the polymer in the first solution, the flow of the first solution into the chamber of second solution, or temperature, is controlled to create a hollow fiber membrane tube having a porosity of between 1 and 2 micrometers. 
     
     
         7 . The process of  claim 1 , wherein said reinforcement member comprises a rigid tube having apertures through sidewalls thereof. 
     
     
         8 . The process of  claim 1 , wherein said reinforcement member comprises a woven polymer sleeve. 
     
     
         9 . The process of  claim 1 , wherein said reinforcement member comprises a spring. 
     
     
         10 . The process of  claim 9 , wherein a rigid wire is associated with said spring. 
     
     
         11 . The process of  claim 1 , including the step of forming an interior end of the tip to fit a catheter introducer. 
     
     
         12 . The process of  claim 1 , including the step of forming a shoulder on the non-porous tubular fiber membrane and the tip to maintain a generally uniform catheter assembly outer diameter. 
     
     
         13 . The process of  claim 1 , wherein the porous fiber membrane has a fluid-flow rate of up to 100 milliliters per hour. 
     
     
         14 . The process of  claim 13 , wherein the porous fiber membrane has a fluid flow rate of approximately 20 milliliters per hour. 
     
     
         15 . The process of  claim 1 , wherein the porous fiber membrane has a porosity of less than 5 micrometers.