Coll-karafin ureteral stent-catheter having varying diameter stent

A ureteral stent-catheter device for implantation in a ureteral meatus, comprising:

• an elongated unitary flexible ureteral stent having preformed set curls at both ends, said ureteral stent having a fluid passage channel extending substantially the entire length of said stent and drain passages formed at least over its proximal end, said drain passages fluidly communicating said fluid passage channel to the outside of said stent, said stent having a first outer width dimension over its proximal two-third length and a second outer width dimension over its distal one-third length, said second outer width dimension being larger than said first outer width dimension, the junction between said proximal two-third and said distal one-third being gradually tapered so that said first width dimension gradually changes to said second width dimension;
• and
• a rigid ureteral catheter dimensioned for inserting into the distal end of said stent to straighten the set curl formed at said distal end of said stent,
• wherein on extraction of said catheter from said distal end of said stent, said distal end recurls, both said curls serving to prevent migration of said stent in the ureteral meatus.

A ureteral stent-catheter device for implantation in a ureteral meatus, comprising in combination:

• an elongated unitary flexible ureteral stent having preformed set curls at both ends, said ureteral stent having a fluid passage channel extending substantially the entire length of said stent and drain passages formed at least over its proximal end, said drain passages fluidly communicating said fluid passage channel to the outside of said stent, said stent having a first outer width dimension over its proximal two-third length and a second outer width dimension over its distal one-third length, said second outer width dimension being larger than said first outer width dimension, the junction between said proximal two-third and said distal one-third being gradually tapered so that said first width dimension gradually changes to said second width dimension;
• a rigid ureteral catheter dimensioned for inserting into the distal end of said stent to straighten the set curl formed at said distal end of said stent;
• and
• a rigid tube having an inner width larger than the outer width dimension of said catheter to permit said rigid tube to slide over said catheter and abut against said distal end of said stent,
• wherein said rigid tube is used for extracting said catheter which is inserted into said distal end by sliding said tube over said catheter and abutting against said distal end and pulling said catheter away from said distal end, whereupon on extraction of said catheter from said distal end, said distal end recurls, both said curls serving to prevent migration of said stent in the ureteral meatus.

A method of inserting an elongated flexible ureteral stent into a renal pelvis comprising the steps of:

• inserting a stiff tubular ureteral catheter into a ureteral catheter receiving segment of an elongated flexible ureteral stent having preformed set curls at both ends thereof and having a fluid passage channel extending substantially the entire length of said flexible stent, and a drain passage segment having a plurality of drain passages communicating said channel to the outside of the stent, said channel within said passage segment having a first channel width, said drain passage segment having a first outer width, one end of said drain passage segment being closed and a portion of said passage segment forming one of said pair of preformed curls;
• and said ureteral catheter receiving segment integral and co-extensive with said passage segment and having a second outer width, said channel extending along the length of said receiving segment and having a second channel width, said second channel width and said second outer width being larger than said first channel width and said first outer width, respectively, wherein the junction between said catheter receiving segment and said drain passage segment being gradually tapered to form a continuous, non-abrupt outer surface, a portion of said catheter receiving segment forming the other preformed curl, to straighten the other curl formed in the distal end;
• inserting a stiffening wire through said catheter and said stent through said channel to straighten the curl formed in the proximal end of said stent;
• inserting the stent-catheter combination through a cystoscope until the proximal end of the stent is within the renal pelvis;
• withdrawing the stiffening wire from the stent-catheter combination thereby allowing the preformed curl at said proximal end to reform and thus allowing the device to function as an externalized ureteral catheter;
• and
• extracting the catheter, allowing the preformed distal curl of the stent to reform to maintain the stent in the renal pelvis.