Compressible ureteral stent for comfort
In one embodiment, the invention is directed to a ureteral stent adapted for placement within a patient's urinary tract to facilitate drainage from the patient's kidney to the patient's bladder. The ureteral stent includes an elongated portion, a retention portion and a mesh or coil portion. The elongated portion has first and second ends, defines an elongated portion of a lumen extending between the first and second ends, and has a length sufficient to extend within the ureter from the patient's kidney to the patient's bladder. The retention portion extends from the first end of the elongated portion, defines a retention portion of the lumen and at least one through aperture for providing fluid communication between the lumen and the kidney. The retention portion is adapted for placement substantially within the kidney and for retaining the placement of the stent within the kidney. The mesh or coil portion extends from the second end of the elongated portion and is adapted for placement substantially within an intramural tunnel portion of the ureter and for extension into the bladder. The mesh or coil portion is collapsible under radial compression to inhibit urine back flow to the kidney.
This application claims priority to and the benefit of the U.S. provisional patent application Ser. No. 60/295,465, filed on Jun. 1, 2001, the entirety of which is incorporated herein by reference.
TECHNICAL FIELDThis invention generally relates to ureteral stents. More particularly in one embodiment, the invention is directed to a ureteral stent having a bladder end adapted to reduce patient discomfort.
BACKGROUND INFORMATIONA stent is a medical device provided for propping open an obstructed passage within the body, such as a blocked ureter. In general, ureteral blockage is a medical condition requiring treatment. A ureteral blockage can occur for a number of reasons, including the passage of a kidney stone and/or other material into the ureter where it becomes entrapped. Also, a tumor growing against the outer wall of the ureter can force compression or constriction of the ureter. A tumor on the internal ureteral wall can also cause blockage of the ureter. Ureteral stents are often used to correct such problems. A ureteral stent may be placed inside the ureter on a temporary basis to allow proper drainage of fluids from the kidney to the bladder. A ureteral stent usually comprises a straight length of hollow tubing with each end having a hook or a curl or other configuration for preventing migration or expulsion of the stent from its placed position within the ureter. One end of a typical ureteral stent is placed in the kidney and the other end is placed in the bladder. The end positioned in the kidney is typically configured to retain the stent within the renal pelvis and to prevent the downward migration of the stent into the ureter. The bladder end of the stent is typically configured to prevent upward migration of the stent towards the kidney.
The invention generally relates to ureteral stents, particularly those that reduce (compared with conventional ureteral stents) patient discomfort when the stent is placed within the patient's body. One object of the invention is to keep the ureteral passage open to allow the flow of fluids from the kidney to the bladder. Another object of the invention is to reduce, minimize or avoid patient discomfort associated with conventional in-dwelling ureteral stents by reducing irritation of the trigone region of the bladder mucosa.
In one embodiment, the invention is directed to a ureteral stent including an elongated portion, a retention portion for placement substantially within a kidney, and a collapsible portion for placement substantially within the intramural tunnel portion of a ureter and extending into the bladder. The elongated portion of the stent has a lumen which extends along the length of the ureter from the kidney to the bladder. According to one feature, the retention portion extends from a first end of the elongated portion and is configured to be retained within the kidney. According to another feature, the collapsible portion extends from a second end of the elongated portion, and it is collapsible under radial compression from the intramural tunnel region to inhibit back flow of urine to the kidney.
In one embodiment, the collapsible portion is fabricated from a mesh material. In another embodiment, the collapsible portion is fabricated from a wound coil. According to one feature, the collapsible portion includes an outer coating of a biocompatible material adapted to avoid tissue ingrowth. According to another feature, the collapsible portion includes an inner lining adapted to avoid urine encrustation on an inner surface of a lumen formed by the collapsible portion which extends from the lumen formed by the elongated portion of the stent.
In another aspect, the invention relates to methods of inserting into a patient one of the ureteral stents mentioned above. One method includes the step of passing a guide wire through the ureter and into the kidney. Thereafter, coaxially sliding a stent over the guide wire and into the ureter by using a tubular stent pusher. One alternate method includes placing a stent with a closed kidney end over a guide wire, and then advancing the stent into the ureter by pushing the guide wire. According to another embodiment, the stent is inserted from the kidney downward through the ureter and into the bladder.
In yet other aspects, the invention features methods of manufacturing stents such as the ureteral stents mentioned above.
The foregoing and other objects, aspects, features and advantages of the invention will become more apparent from the following description and from the claims.
BRIEF DESCRIPTION OF THE DRAWINGSThe foregoing and other objects of the invention and the various features thereof may be more fully understood from the following description when read together with the accompanying drawings in which like reference characters generally refer to the same parts throughout the different views and in which the depicted components are not necessarily drawn to scale:
As discussed above in summary, in one embodiment, the invention is directed to a ureteral stent having a bladder end adapted to reduce patient discomfort.
The retention portion 204 extends from the kidney end 212 of the ureteral stent 200, and is adapted for placement substantially within the kidney 106, and for retention of the placement. According to one feature, the retention portion 204 includes one or more through apertures or eye ports 211 for providing fluid communication between an outer wall (shown at
The collapsible portion 206 extends from the bladder end 214 of the ureteral stent 200, and is adapted for residing substantially within the intramural tunnel region 122 of the ureter 102 and for extending into the bladder 110. According to an illustrative embodiment, the invention addresses reflex prevention and intramural tunnel irritation via the collapsible portion 206 of the ureteral stent 200.
The collapsible portion 206 also defines an inner lumen 406 which extends from the internal lumen 400 of the elongated portion 202. The inner lumen 406 terminates in at least one through aperture 408. As shown in
In one preferred embodiment, the collapsible mesh portion 500 includes both an outer covering 600 as well as an inner lining 602. In the illustrative embodiment, the mesh portion 500 is sandwiched between an outer covering 600 and an inner lining 602, which encase the exterior and the interior of the mesh portion 500 respectively. In another embodiment, a polymer is interspersed within the mesh.
In one preferred embodiment of the invention, the wound coil 700 includes both an outer covering 800 as well as an inner lining 802. In the illustrative embodiment, the wound coil 700 is sandwiched between an outer covering 800 and an inner lining 802, which encase the exterior and the interior portions of the wound coil 700 respectively.
Various methods are used for inserting the ureteral stent 200 into a patient. In one embodiment of the invention, the retention portion 204 of the ureteral stent 200 is inserted though the urethral opening 114 of a patient, advanced through the bladder 110 and the ureter 102, and subsequently placed in the kidney 106 of the patient. Prior to insertion, the collapsible portion 206 is temporarily collapsed to facilitate insertion into the patient's body. The retention portion 204 is also straightened out prior to insertion.
In yet another embodiment of the invention, a cytoscope is used for inserting the ureteral stent 200 of the invention into a patient. In this embodiment, the ureteral stent 200 is inserted within the cytoscope prior to insertion into the urinary tract 100 and the cytoscope is removed subsequent to proper positioning of the ureteral stent 200 within the patient.
In yet another embodiment, the mesh portion 500 of the ureteral stent 200 is maintained to have a sufficiently large inner diameter, so as to allow passage over a guide wire.
In one aspect of the invention, a method of manufacturing the collapsible mesh portion 500 of the ureteral stent is 200 described. The mesh portion 500 is fabricated from polymeric or metallic materials, such as, for example, stainless steel, tantalum, gold, titanium, nitinol, polytetrafluoroethylene (PTFE) or any suitable plastic material that is collapsible when formed and radially expandable.
The mesh portion 500 can be of any design or configuration and is made in any manner described in the art. In one embodiment of the invention, the mesh is braided in a “2 over-2 under” helical pattern. The mesh braid is then laminated over the bladder end 214 of the elongated portion 202 of the ureteral stent 200.
In another embodiment, individual mesh strands are attached to each other via thermal bonding, in the case of polymeric materials, or via resistance welding or use of an adhesive in the case where metallic elements are utilized.
In yet another embodiment, the braided mesh is braided directly over the bladder end 214 of the ureteral stent 200 using a pre-heat step to embed the braid onto the bladder end 214. In another aspect of the invention, ureteral stent 200 is prepared by hollowing out a metal pipe to leave a stent skeleton. Exemplary processes known in the art for preparation of the ureteral stent 200, include an etching process, also known as photo-fabrication; processes that employ masks and chemicals; electric discharge machining processes; and mechanical machining processes or stamping an open-cell pattern into a solid tube which is usually made of a polymeric material.
A ureteral stent 200 is used to treat ureteral blockage for proper drainage of fluids between the kidney 106 and the bladder 110. Treatment of ureteral blockage is provided, for example, by inserting a ureteral stent 200 over a guide wire with a pusher through the urethral opening 114 and into the bladder 110. The guide wire or a cannula is used temporarily to straighten out the retention portion 204 of the ureteral stent 200. The retention portion 204 of the uretral stent 200 is typically made from material that is able to regain its structure after distortion which allows for the retention portion 204 to be straightened out prior to placement within the body.
In one aspect of the invention, a method for treating ureteral blockage in a patient includes sliding the ureteral stent 200 over a guide wire. The guidewire is inserted into the body of a patient through the bladder 110 and into the ureter 102. A ureteral stent 200 is subsequently slid over the guide wire, such that one end of the guide wire is inserted through the kidney end 212 of the ureteral stent 200. The ureteral stent 200 is moved along the length of the guide wire by the use of a pusher which includes a lumen to accept a guide wire.
In a preferred embodiment of the invention, the collapsible mesh portion 500 maintains a sufficiently large inner diameter so as to allow passage over a 0.035″/0.038″ guide wire. In one embodiment, the ureteral stent 200 is tracked over the wire for positioning inside the body using conventional methods of placement such as a pusher to abut the retention portion 204 of the ureteral stent 200.
Variations, modifications, and other implementations of what is described herein will occur to those of ordinary skill in the art without departing from the spirit and the scope of the invention. This invention is not limited to the preceding illustrative description.
Claims
1-28. (canceled)
29. A ureteral stent, comprising:
- an elongated portion having a first end and a second end, the elongated portion defining a lumen extending between the first end and the second end, the elongated portion having a length sufficient to extend substantially from a kidney of a patient to a bladder of the patient; and
- a compressible portion extending from the second end of the elongated portion, the compressible portion being adapted for placement substantially within an intramural tunnel portion of the ureter and being collapsible under radial compression of the type exerted by the intramural tunnel portion of the ureter to a degree sufficient to substantially inhibit backflow of urine through the lumen toward the first end, the compressible portion and the elongated portion having substantially the same outer diameter.
30. The ureteral stent of claim 29, wherein the compressible portion includes a covering.
31. The ureteral stent of claim 30, wherein the covering includes a polymer.
32. The ureteral stent of claim 29, further comprising:
- a retention portion extending from the first end of the elongated portion, the retention portion being adapted for placement substantially within the kidney of the patient.
33. The ureteral stent of claim 29, wherein the compressible portion includes a mesh construction.
34. The ureteral stent of claim 29, wherein the compressible portion includes a coil construction.
35. The ureteral stent of claim 32, wherein the retention portion defines an aperture, the aperture providing communication between the lumen defined by the elongated portion and the kidney.
36. The ureteral stent of claim 29, wherein the elongated portion includes a substantially continuous sidewall.
37. A ureteral stent, comprising:
- an elongated portion having a first end and a second end, the elongated portion defining a lumen extending between the first end and the second end and having a length sufficient to extend from a kidney of a patient to a bladder of the patient;
- a compressible portion extending from the second end of the elongated portion, the compressible portion being adapted for placement substantially within an intramural tunnel portion of the ureter and being collapsible under radial compression from the intramural tunnel portion of the ureter, the compressible portion configured to be more easily compressed than the elongated portion; and
- a covering disposed on the compressible portion.
38. The ureteral stent of claim 37, wherein the covering is disposed on an outer surface of the compressible portion.
39. The ureteral stent of claim 37, wherein the covering is disposed on an inner surface of the compressible portion.
40. The ureteral stent of claim 37, further comprising:
- a retention portion extending from the first end of the elongated portion, the retention portion being adapted for placement substantially within the kidney of the patient.
41. The ureteral stent of claim 37, wherein the compressible portion includes a mesh construction.
42. The ureteral stent of claim 37, wherein the covering is a first covering, the first covering disposed on an outer surface of the compressible portion, the ureteral stent further comprising:
- a second covering disposed on an inner surface of the compressible portion.
43. A ureteral stent, comprising:
- an elongated portion having a first construction and having a first end and a second end, the elongated portion defining a lumen extending between the first end and the second end, the elongated portion having a length sufficient to extend substantially from a kidney of a patient to a bladder of the patient; and
- a compressible portion extending from the second end of the elongated portion, the compressible portion being adapted for placement substantially within an intramural tunnel portion of the ureter and being collapsible under radial compression of the type exerted by the intramural tunnel portion of the ureter, the compressible portion having a second construction different than the first construction.
44. The ureteral stent of claim 43, wherein the compressible portion includes an outer covering.
45. The ureteral stent of claim 43, wherein the compressible portion includes an inner lining.
46. The ureteral stent of claim 43, wherein the compressible portion includes a mesh construction.
47. The ureteral stent of claim 43, wherein the compressible portion includes a coil construction.
48. The ureteral stent of claim 43, wherein the elongated portion includes a substantially continuous sidewall.
Type: Application
Filed: Apr 20, 2005
Publication Date: Aug 25, 2005
Inventor: John McWeeney (Brighton, MA)
Application Number: 11/109,696