CA2179668C

CA2179668C - Esophageal stent and delivery tool

Info

Publication number: CA2179668C
Application number: CA002179668A
Authority: CA
Inventors: Liann M. Johnson; Richard J. Thompson; John A. Scholl
Original assignee: Schneider USA Inc
Current assignee: Schneider USA Inc
Priority date: 1992-05-08
Filing date: 1993-03-10
Publication date: 1999-07-20
Anticipated expiration: 2013-03-10
Also published as: CA2179668A1

Abstract

A radially self-expanding stent particularly suited for treating esophageal strictures, includes a medial region and proximal and distal cuffs having diameters greater than the medial region diameter when the stent is in the relaxed state. A silicone coating circumscribes the medial region, but the cuffs are not coated and retain their open weave construction. As a result, the cuffs remain particularly well suited to immediately contact esophageal wall tissue and resist stent migration, while the silicone coated medial region provides a barrier to tumor ingrowth, and has an enhanced radial restoring force to maintain an open passage-way in the esophagus. A deployment device for the stent includes an interior catheter surrounded by the stent and having an esophageal dilation feature, along with an exterior catheter that radially compresses the stent. A low durometer sleeve, fixed to the interior tube and in surface engagement with the compressed stent, tends to fix the axial position of the stent relative to the interior catheter whenever the exterior catheter is moved axially relative to the inner catheter. Consequently, precision in stent placement and the ability to recapture a partially deployed stent are enhanced.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
I. An apparatus for deploying a radially self-expanding stent within a body Lumen, including:
a stent confining means for elastically compressing a radially self-expanding stent to a delivery configuration in which the self-expanding stmt has a reduced radius along its entire axial length, said stmt confining means having a proximal end that remains outside of the body;
an elongate and flexible stmt delivery device having a proximal end, a distal end, a proximal region near the proximal end and a distal region near the distal end for use in delivering the radially self-expanding stmt into a body lumen and in positioning the stmt at a treatment site within the body lumen with the stent surrounding the delivery device along the distal region, while the proximal end and the proximal region of the flexible delivery device remain outside of the body;
an axial stmt restraining means disposed along the distal region of the delivery device; and a control means operably associated with the confining means and movable axially along the proximal region of the delivery device to move the confining means axially relative to the delivery device toward and away from a confinement position in which the confining means compresses the self-expanding stent into the delivery configuration and urges the stent into a surface engagement with the axial stent restraining means; wherein the axial stent restraining means, due to said surface engagement, tends to maintain the self-expanding stent axially aligned with the deployment device as the confining means is moved axially away from the confinement position to release the stent for radial self-expansion;
characterized in that visible indicia are provided along the proximal region of the stmt delivery device to define a plurality of segments arranged axially along said proximal region of the delivery device, each of the segments being associated with a different one of a plurality of stages of said release of the stent, whereby an axial alignment of the control means with each of the segments visibly indicates the position of the proximal end of the stmt confining means with respect to the proximal region of the stent delivery device and thereby also indicates the position of a distal end of the stent confining means with respect to the distal region of the stent delivery device and further indicates the associated stage of said release of the stmt, thereby to facilitate a monitoring of said release.
2. The apparatus of claim 1 characterized in that the axial stmt restraining means has a durometer hardness substantially less than the durometer hardness of the stent confining means, the arrangement being such that the axial stent restraining means, due to said surface engagement and the resulting elastic deformation, tends to maintain the self-expanding stmt axially fixed relative to the delivery device as the confining means is moved axially away from the confinement position to release the stent for radial self-expansion.
3. The apparatus of claim 1 or claim 2 wherein:
the stent delivery device comprises a first elongate and flexible length of tubing having a central lumen running the axial length of said first tubing, for accommodating a guidewire.
4. The apparatus of claim 2 or claim 3 further including:
a distal tip at the distal end of the said first tubing, for dilating a malignant stricture at the treatment site.
5. The apparatus of claim 2 wherein:
the stent confining means comprises a second elongate and flexible length of tubing having a lumen running the length thereof, and wherein the first length of tubing is contained within the lumen with a proximal portion of the first tubing extended proximally of the second tubing when the second tubing is in the confinement position.
6. The apparatus of claim 5 wherein:
the control means comprises a first hub at the proximal end of the first tubing and a second hub at the proximal end of the second tubing.
7. The apparatus of claim 5 wherein:
the axial restraining means comprises a sleeve surrounding the first tubing along the distal region.
8. The apparatus of claim 7 further including:

an adhesive applied to an exterior surface of the sleeve.
9. The apparatus of claim 5 wherein:
the axial stent restraining means comprises a plurality of elongate strips disposed along the distal region.
10. The apparatus of claim 9 wherein:
the strips are oriented axially and spaced apart angularly from one another to form a set of the strips surrounding the first tubing.
11. The apparatus of claim 10 further including:
an adhesive Layer along a radially outward surface of each of the strips.
12. The apparatus of any one of claims 1 to 11 further including:
visible markings along at least a proximal region of the second tubing for indicating the extent of insertion of the second tubing into the body lumen.
13. The apparatus of claim 5 further including:
a detent device removably mounted to the first tubing along the proximal portion for preventing any substantial axial movement of the first tubing relative to the second tubing to maintain the second tubing in the confinement position.
14. The apparatus of any one of claims 1 to 13 further including:

an enlargement feature near the distal end of the stent delivery device, said enlargement feature having a diameter substantially equal to an interior diameter of the first tubing, a distal transition region diverging proximally from the tip to a mid portion of the enlargement feature, and a proximal transition region converging in the proximal direction from the enlargement feature mid portion.