In-dwelling ureteral stent and injection stent assembly, and method of using same

An injection push ureteral catheter assembly comprising:

• (a) an in-dwelling ureteral stent comprising a first flexible tubular portion with a straight section and a curlable section at the proximal end thereof and a second flexible portion providing a tubular curlable section at the distal end, said second portion having a larger inner diameter than the outer diameter of said first portion and seating therein the end of said straight portion of said first portion, said seated end being bonded to the inner surface of said second portion, whereby the end of said straight section within said second portion forms an internal shoulder facing said distal end within said second portion and against which an injection push catheter may abut, said stent being fabricated from synthetic resin and said second portion having an outer surface which is softer than the outer surface of said first portion;
• (b) a guide wire of a lesser diameter extending in the passage through said stent and having a stiffness sufficient to straighten said curled portions thereof;
• and
• (c) a tubular push catheter having a passage therethrough in which is received said guide wire, the wall of said push catheter having a diameter smaller than the inner diameter of said second portion and seating within the passage of said second portion of said stent, and said push catheter being of larger diameter than the inner diameter of said first portion, said inner end of push catheter abutting said internal shoulder to permit said stent to be pushed along said guide wire as said push catheter is pushed therealong.

In the method of inserting a ureteral stent into the ureter of a patient, the steps comprising:

• (a) inserting a guide wire through the ureter and into the kidney of the patient;
• (b) sliding onto said guide wire a ureteral stent comprising a first flexible tubular portion with a straight section and a curled section at the proximal end thereof and a second flexible portion providing a tubular curled section at the distal end, said second portion having a larger inner diameter than the outer diameter of said first portion and seating therein the end of said straight section of said first portion, said seated end being bounded to the inner surface of said second portion, whereby the end of said straight section within said second portion forms an internal shoulder facing said distal end within said second portion and against which an injection push catheter may abut, said stent being fabricated from synthetic resin and said second portion having an outer surface which is softer than the outer surface of said first portion, said curled sections being straightened by said guide wire as they pass thereonto;
• (c) sliding onto said guide wire a tubular push catheter having a passage therethrough receiving said guide wire, the wall of said push catheter having an outer diameter smaller than the inner diameter of said second portion and larger than the inner diameter of said first portion, said push catheter having its proximal end seated within said passage of said second portion of said stent and abutting said internal shoulder;
• (d) continuing to push said push catheter, and thereby said stent, along said guide wire until the proximal end of said stent is disposed within the renal pelvis;
• (e) removing said guide wire from said stent and said push catheter whereby the proximal end of said stent curls within said renal pelvis to anchor it therein;
• and
• (f) withdrawing said push catheter from said passage in said second portion of said stent whereby said second portion curls in the patient's bladder.