Medical stent and related methods

• US 7,291,180 B2
• Filed: 01/27/2004
• Issued: 11/06/2007
• Est. Priority Date: 04/02/2001
• Status: Expired due to Term

• Current Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Inventors: St. Pierre, Ernest J.
• Primary Examiner(s): SNOW, BRUCE EDWARD
• Application Number:
  US10/765,382
• Publication Number:
  US 20040186552A1
• Time in Patent Office: 1,379 Days
• Field of Search: 623/23.7, 623/23.65, 623/23.66, 604/8
• US Class Current: 623/23.66
• CPC Class Codes: A61F 2250/0019 differing in hardness, e.g. Vickers, Shore, Brinell
• CPC Class Codes: A61M 25/0009 Making of catheters or other medical or surgical tubes
• CPC Class Codes: A61M 25/0041 pre-formed, e.g. specially adapted to fit with the anatomy of body channels urethral catheters A61F2/04
• CPC Class Codes: A61M 25/0054 with regions for increasing flexibility
• CPC Class Codes: A61M 27/008 pre-shaped, for use in the urethral or ureteral tract

Abstract

A medical stent is sized for placement in a ureter. The stent includes a first section which includes a first material, defines a lumen, and includes a first coil completing at least one revolution. A second section of the stent includes a second material, defines a lumen, and includes a second coil completing at least one revolution. A third section defines a lumen and is located between the first and second sections. The third section includes a co-extrusion of the first and second materials. One of the first or second sections is harder than the other section.

Claims

1. A medical stent comprising:

a single-piece stent body comprising;

a first section defining a lumen and comprising a first retention structure, the first section comprising a first material having a first durometer value;

a second section defining a lumen and comprising a second retention structure, the second section comprising a second material having a second durometer value, wherein the second durometer value is greater than the first durometer value; and

a third section defining a lumen having a longitudinal axis, the third section located between the first and second sections, wherein the third section comprises a co-extrusion of the first and second materials, the first material and the second material being distinct from each other and arranged substantially asymmetrically within a plane normal to the longitudinal axis, the relative amount of the first material and the second material within the third section varying non-linearly within a plane parallel to the longitudinal axis.

2. The stent of claim 1 wherein the first material comprises ethylene vinyl acetate.

3. The stent of claim 1 wherein the first material has a durometer value of about 70 to about 90 on a Shore A scale.

4. The stent of claim 1 wherein the second material has a durometer value of about 80 to about 95 on a Shore A scale.

5. The stent of claim 1 wherein a cross-section of the lumen in at least one of the first, second, and third sections is circular.

6. The stent of claim 1 wherein a cross-section of at least one of the first, second, and third sections is circular.

7. The stent of claim 1 wherein at least one of the first, second, and third section comprises a radiopaque material.

8. The stent of claim 1 wherein the stent body does not substantially soften when exposed to a temperature of a human body.

9. The stent of claim 1 wherein at least a portion of the stent body is sized for placement in a ureter.

10. The stent of claim 1 wherein an outer surface of the third section smoothly transitions to outer surfaces of the first and second sections immediately proximate the third section and an inner diameter of the third section is substantially constant through the third section and on either side of the third section immediately proximate to the third section in the first and second sections.

11. The stent of claim 1 wherein an inner diameter of third section is substantially constant through the third section and on either side of the third section immediately proximate to the third section in the first and second sections.

12. The stent of claim 1, wherein the first section is devoid of the second material.

13. The stent of claim 1, wherein the second section is devoid of the first material.

14. A medical stent comprising:

a single-piece stent body comprising;

a first section defining a lumen and comprising a first retention structure, the first section comprising a first material having a first retention strength;

a second section defining a lumen and comprising a second retention structure, the second section comprising a second material having a second retention strength, wherein the second retention strength is greater than the first retention strength; and

a third section defining a lumen having a longitudinal axis, the third section located between the first and second sections, wherein the third section comprises a co-extrusion of the first and second materials, the first material and the second material being distinct from each other and arranged substantially asymmetrically within a plane normal to the longitudinal axis, the amount of any one of the first material or the second material within the third section varying non-linearly within a plane parallel to the longitudinal axis.

15. The stent of claim 14 wherein the stent body does not substantially soften when exposed to a temperature of a human body.

16. The stent of claim 14 wherein at least a portion of the stent body is sized for placement in a ureter.

17. The stent of claim 14 wherein an outer surface of the third section smoothly transitions to outer surfaces of the first and second sections immediately proximate the third section.

18. The stent of claim 14 wherein an inner diameter of the third section is substantially constant through the third section and on either side of the third section immediately proximate to the third section in the first and second sections.

19. The stent of claim 14, wherein the first section is devoid of the second material and the second section is devoid of the first material.

20. A method for placing a medical stent comprising:

inserting a medical stent into a ureter, the medical stent comprising;

a single-piece stent body comprising;

a first section defining a lumen and comprising a first retention structure, the first section comprising a first material having a first durometer value;

a second section defining a lumen and comprising a second retention structure, the second section comprising a second material having a second durometer value, wherein the second durometer value is greater than the first durometer value; and

a third section defining a lumen having a longitudinal axis, the third section located between the first and second sections, wherein the third section comprises a co-extrusion of the first and second materials the first material and the second material being distinct from each other and arranged substantially asymmetrically within a plane normal to the longitudinal axis, the amount of any one of the first material or the second material within the third section varying non-linearly within a plane parallel to the longitudinal axis.