US20050187510A1 - Compressible ureteral stent for comfort - Google Patents

Abstract

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.

Description

CROSS-REFERENCE TO RELATED CASE
• 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 FIELD
• This 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 INFORMATION
• A 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.
• FIG. 1 is a conceptual background drawing showing a portion of the human urinary tract. Referring toFIG. 1, in a humanurinary tract100, theureters102 and104 transport urine from thekidneys106 and108 to thebladder110. The trigone region of thebladder112 is located between the urethral opening114 and the twoureteral orifices116 and118. The pain associated with an in-dwelling ureteral stent is attributable in-part to contact between the stent and thebladder mucosa120 in thetrigone region112. Thetrigone region112 is believed to be particularly innervated and sensitive to the presence of any foreign bodies such as the bladder end of a ureteral stent. Theintramural tunnel regions122 and124 of theureters102 and104, respectively, act like valves, shutting off to prevent back flow of urine from thebladder112 to thekidneys106 and108. Theintramural tunnel regions122 and124 are also believed to be particularly innervated and sensitive to the presence of any foreign bodies. In addition, further discomfort due to in-dwelling stents can be caused by flank pain due to urine shooting from thebladder110 back up theureters102 and104 intra-luminally via the stent, and/or extra-luminally around the stent.
SUMMARY OF THE INVENTION
• 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 DRAWINGS
• The 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:
• FIG. 1 is a schematic view of a human urinary tract;
• FIG. 2 is a schematic view of a ureteral stent according to an illustrative embodiment of the invention;
• FIG. 3A is a schematic view of a ureteral stent according to an illustrative embodiment of the invention, and positioned within a human urinary tract;
• FIG. 3B is a schematic view of the stent ofFIG. 3A, including an illustrative bladder end in a collapsed state;
• FIG. 4A is a longitudinal, cross-sectional view of the stent ofFIG. 2;
• FIG. 4B is a transverse, cross-sectional view of the stent of4A, taken along the line A-A′;
• FIG. 5A is an enlarged side view of an illustrative collapsible mesh portion of a stent ofFIG. 2, in an expanded and open state;
• FIG. 5B is a longitudinal, cross-sectional view of the illustrative mesh portion of the stent ofFIG. 5A, in an expanded and open state;
• FIG. 5C is a longitudinal, cross-sectional view of the illustrative mesh portion of the stent ofFIG. 5A, in a collapsed condition due to radial compression;
• FIG. 6A is a longitudinal, cross-sectional view of the illustrative mesh portion of the stent ofFIG. 5A, including an outer covering;
• FIG. 6B is a longitudinal, cross-sectional view of the illustrative mesh portion of the stent ofFIG. 5A, including an inner lining;
• FIG. 6C is a longitudinal, cross-sectional view of the illustrative mesh portion of the stent ofFIG. 5A, including both an inner lining and an outer covering;
• FIG. 7A is an enlarged side view of an illustrative collapsible wound coil portion of the stent ofFIG. 2, in an expanded and open state;
• FIG. 7B is a longitudinal, cross-sectional view of the illustrative wound coil portion of the stent ofFIG. 7A, in an expanded and open state;
• FIG. 7C is an enlarged side view of the illustrative wound coil portion of the stent ofFIG. 7A, in a collapsed state;
• FIG. 8A is a longitudinal, cross-sectional view, according to an illustrative embodiment of the wound coil portion ofFIG. 7A, including an outer covering;
• FIG. 8B is a longitudinal, cross-sectional view, according to an illustrative embodiment of the wound coil portion ofFIG. 7A, including an inner lining;
• FIG. 8C is a longitudinal, cross-sectional view, according to an illustrative embodiment of the wound coil portion ofFIG. 7A, including both an inner lining and an outer covering;
• FIG. 9 is a transverse, cross-sectional view of the mesh portion ofFIG. 4A, taken along the line B-B′ inFIG. 4A;
• FIG. 10A is a schematic view of the stent ofFIG. 2 having a J-shaped kidney retention portion, according to an illustrative embodiment of the invention;
• FIG. 10B is a schematic view of the stent ofFIG. 2 having a single loop shaped kidney retention portion, according to an illustrative embodiment of the invention; and
• FIG. 10C is a schematic view of the stent ofFIG. 2 having a multi loop shaped kidney retention portion, according to an illustrative embodiment of the invention.
ILLUSTRATIVE DESCRIPTION
• 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.FIG. 2 depicts aureteral stent200 in accordance with an illustrative embodiment of the invention.FIGS. 3A and 3B depict theureteral stent200 placed inside a humanurinary tract100. A skilled artisan will appreciate that a ureteral stent of the invention can be placed in eitherureter102 or104. However, for simplicity, the following discussion is limited to placement of theureteral stent200 within theureter102. As depicted, the illustrativeureteral stent200 includes anelongated portion202, aretention portion204, and acollapsible portion206. Theelongated portion202 has alength208 that is sufficient to extend through theureter102 from thekidney106 to thebladder110. Theelongated portion202 of theureteral stent200 defines a lumen (shown inFIGS. 4A and 4B at400) extending from akidney end212 to abladder end214. According to the illustrative embodiment, theureteral stent200 also includes one or more through apertures oreye ports210 located along the length of theelongated portion202 for providing fluid communication between an outer wall (shown inFIGS. 4A and 4B at412) and an inner lumen wall (shown inFIG. 4B at410) to further enable drainage through theinternal lumen400 of theureteral stent200. According to one feature, theelongated portion202 is made of a physiologically compatible material such as, for example, polyvinyl alcohol, polyethylene oxide, hydroxy ethyl cellulose, stainless steel, or the like.
• Theretention portion204 extends from thekidney end212 of theureteral stent200, and is adapted for placement substantially within thekidney106, and for retention of the placement. According to one feature, theretention portion204 includes one or more through apertures oreye ports211 for providing fluid communication between an outer wall (shown atFIG. 4A at414) and an inner lumen (shown inFIG. 4A at402) to further enable drainage through theinternal lumens400 and402.
• Thecollapsible portion206 extends from thebladder end214 of theureteral stent200, and is adapted for residing substantially within theintramural tunnel region122 of theureter102 and for extending into thebladder110. According to an illustrative embodiment, the invention addresses reflex prevention and intramural tunnel irritation via thecollapsible portion206 of theureteral stent200.
• FIG. 3A depicts theintramural tunnel region122 in a relaxed state and thecollapsible portion206 of theureteral stent200 in an expanded and open state. As shown inFIG. 3B, as theintramural tunnel region122 contracts radially, thecollapsible portion206 collapses to restrict urine back flow frombladder110 to thekidney106.
• FIG. 4A is a schematic of a longitudinal, cross-sectional view of theureteral stent200.FIG. 4B is a lateral cross-sectional view of thelength208 of theelongated portion202 taken along the view A-A′. As mentioned above, and as shown inFIGS. 4A and 4B, theelongated portion202 of theureteral stent200 defines aninternal lumen400 that extends through theelongated portion202 between thekidney end212 and thebladder end214. Theretention portion204 also defines aninternal lumen402 which extends from thelumen400 of theelongated portion202. Theretention portion204 includes at least one throughaperture404 adapted for providing fluid communication between theinternal lumen402 and thekidney106.
• Thecollapsible portion206 also defines aninner lumen406 which extends from theinternal lumen400 of theelongated portion202. Theinner lumen406 terminates in at least one throughaperture408. As shown inFIGS. 3A and 3B, when placed in a patient, the throughaperture408 resides within thebladder110 and is adapted for providing urine flow from thelumen406 into thebladder110.
• FIG. 5A depicts one illustrative embodiment in which thecollapsible portion206 of aureteral stent200 of the invention includes amesh portion500. Illustratively, themesh portion500 extends from thebladder end214 of theelongated portion202. InFIG. 5A, themesh portion500 is depicted in an expanded and open state.FIG. 5B is a longitudinal, cross-sectional view of thecollapsible portion206 of the stent ofFIG. 5A in the expanded and open state. As shown, themesh portion500 forms aninner lumen502 which extends from theinternal lumen400 of theelongated portion202. Thelumen502 ends in at least oneopening504 which resides in thebladder110 to allow fluid communication between thelumen502 and thebladder110.FIG. 5C is a longitudinal, cross-sectional view of thecollapsible mesh portion500, shown in a collapsed state. As discussed above, thecollapsible portion206 collapses, for example, due to a radial force exerted on the exterior of themesh portion500, and inhibits through fluid flow. In one illustrative embodiment, themesh portion500 is manufactured from polymeric or metallic materials such as, for example, stainless steel, tantalum, gold, titanium, nitinol, polytetrafluoroethylene (PTFE) or any suitable material that collapses under an exerted force of the type exerted by theintramural tunnel region122 of theureter102, and returns to an expanded state upon removal of such a force. One advantage of the invention is that thecollapsible mesh portion500 of theureteral stent200 prevents fluid flow in response to radial force exerted by theintramural tunnel region122 by collapsing to inhibit vesicourinal reflux, back flow of urine and flank pain in a patient.
• FIGS. 6A-6C depict enlarged longitudinal, cross-sectional views, further illustrating embodiments of themesh portion500. As shown inFIG. 6A, in one illustrative embodiment, thecollapsible mesh portion500 has anouter covering600. In the illustrative embodiment, theouter covering600 is formed from a flexible polymer such as, for example, polyurethane, polyamide, silicone, polyvinyl chloride, or the like. As shown inFIG. 6B, in a further illustrative embodiment,collapsible mesh portion500 has aninner lining602 such as, for example, a jacket or a sleeve. In one embodiment, theinner lining602 encases the interior of themesh portion500. Theinner lining602 functions to substantially prevent internal mesh encrustation due to urine contact. In the illustrative embodiment, theinner lining602 is fabricated from a polymer such as, for example, polyurethane, polyamide, silicone, polyvinyl chloride, or the like.
• In one preferred embodiment, thecollapsible mesh portion500 includes both anouter covering600 as well as aninner lining602. In the illustrative embodiment, themesh portion500 is sandwiched between anouter covering600 and aninner lining602, which encase the exterior and the interior of themesh portion500 respectively. In another embodiment, a polymer is interspersed within the mesh.
• FIGS. 7A-7C depict an alternative embodiment in which thecollapsible portion206 of theureteral stent200 includes awound coil700 instead of amesh portion500. Thewound coil700 behaves similarly to themesh portion500, in that under radial force from theintramural tunnel region122 of theureter102, thewound coil700 flattens out to close off the lower portion of theureter102 and thus prevent urine back flow to thekidney106.FIG. 7A depicts one illustrative embodiment in which thewound coil700 extends from thebladder end214 of theelongated portion202. InFIG. 7A, thewound coil700 is depicted in an open and expanded state.FIG. 7B is a longitudinal, cross-sectional view of thecollapsible portion206 of the ureteral stent ofFIG. 7A in an open and expanded state. As shown, thewound coil700 forms alumen702 which extends from theinternal lumen400 of theelongated portion202.FIG. 7C is an illustrative embodiment featuring thewound coil700 in a collapsed state. As discussed above, thewound coil700 collapses, for example, due to radial force exerted on the exterior of thewound coil700 and inhibits fluid flow through thelumen702. In response to the radial force being removed, theradial wound coil700 returns to the expanded and open state.
• FIGS. 8A-8C depict enlarged longitudinal cross-sectional views, further illustrating embodiments of thewound coil700. As shown inFIG. 8A, thecollapsible wound coil700 has anouter covering800. In an illustrative embodiment, theouter covering800 is formed from a flexible polymer such as, for example, polyurethane, polyamide, silicone, polyvinyl chloride, or the like. As shown inFIG. 8B, in a further illustrative embodiment, thewound coil700 has aninner lining802, such as, for example, a jacket or a sleeve. In one embodiment, theinner lining802 encases the interior of thelumen702 of thewound coil700. In the illustrative embodiment, theinner lining802 is fabricated from a polymer such as, for example, polyurethane, polyamide, silicone, polyvinyl chloride, or the like.
• In one preferred embodiment of the invention, thewound coil700 includes both anouter covering800 as well as aninner lining802. In the illustrative embodiment, thewound coil700 is sandwiched between anouter covering800 and aninner lining802, which encase the exterior and the interior portions of thewound coil700 respectively.
• FIG. 9 is an enlarged, transverse cross sectional end view of theterminal end416 of thecollapsible portion206 taken along view B-B′. In one preferred embodiment, thecollapsible portion206 has apolymeric ring900 extending circumferentially around itsterminal end416. According to the illustrative embodiment, the polymeric900 ring protects, for example, the jagged edges of themesh portion500 or woundcoil700 and helps to maintain the shape of themesh portion500 or woundcoil portion700 after theureteral stent200 is placed within a patient. Preferably, thepolymeric ring900 is made from a thermoplastic polymer. In yet another embodiment, a retention flange is used instead of a polymeric ring.
• FIGS. 10A-10C are conceptual drawings depicting various illustrative embodiments of theretention portion204. Theretention portion204 of theureteral stent200 may be shaped, for example, as a hook, a coil or a malecot, or the like, to facilitate its retention in thekidney106. In one illustrative embodiment, shown inFIG. 10A, theretention portion204 of theureteral stent200 is shaped like aJ hook1000. In another illustrative embodiment, shown inFIG. 10B, theretention portion204 of theureteral stent200 has a single loop configuration1002. In a preferred illustrative embodiment of the invention, depicted inFIG. 10C, theretention portion204 has amulti-loop configuration1004. In this illustrative embodiment, themulti-loop configuration1004 allows theureteral stent200 to compensate for any changes in the length of theureter102 caused by peristalsis in theurinary tract100. Themulti-loop configuration1004 also enables the accommodation of different ureteral sizes in different size patients.
• Various methods are used for inserting theureteral stent200 into a patient. In one embodiment of the invention, theretention portion204 of theureteral stent200 is inserted though theurethral opening114 of a patient, advanced through thebladder110 and theureter102, and subsequently placed in thekidney106 of the patient. Prior to insertion, thecollapsible portion206 is temporarily collapsed to facilitate insertion into the patient's body. Theretention portion204 is also straightened out prior to insertion.
• In yet another embodiment of the invention, a cytoscope is used for inserting theureteral stent200 of the invention into a patient. In this embodiment, theureteral stent200 is inserted within the cytoscope prior to insertion into theurinary tract100 and the cytoscope is removed subsequent to proper positioning of theureteral stent200 within the patient.
• In yet another embodiment, themesh portion500 of theureteral stent200 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 thecollapsible mesh portion500 of the ureteral stent is200 described. Themesh portion500 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.
• Themesh portion500 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 thebladder end214 of theelongated portion202 of theureteral stent200.
• 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 thebladder end214 of theureteral stent200 using a pre-heat step to embed the braid onto thebladder end214. In another aspect of the invention,ureteral stent200 is prepared by hollowing out a metal pipe to leave a stent skeleton. Exemplary processes known in the art for preparation of theureteral stent200, 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.
• Aureteral stent200 is used to treat ureteral blockage for proper drainage of fluids between thekidney106 and thebladder110. Treatment of ureteral blockage is provided, for example, by inserting aureteral stent200 over a guide wire with a pusher through theurethral opening114 and into thebladder110. The guide wire or a cannula is used temporarily to straighten out theretention portion204 of theureteral stent200. Theretention portion204 of theuretral stent200 is typically made from material that is able to regain its structure after distortion which allows for theretention portion204 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 theureteral stent200 over a guide wire. The guidewire is inserted into the body of a patient through thebladder110 and into theureter102. Aureteral stent200 is subsequently slid over the guide wire, such that one end of the guide wire is inserted through thekidney end212 of theureteral stent200. Theureteral stent200 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, thecollapsible mesh portion500 maintains a sufficiently large inner diameter so as to allow passage over a 0.035″/0.038″ guide wire. In one embodiment, theureteral stent200 is tracked over the wire for positioning inside the body using conventional methods of placement such as a pusher to abut theretention portion204 of theureteral stent200.
• 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 (21)

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 ofclaim 29, wherein the compressible portion includes a covering.

31. The ureteral stent ofclaim 30, wherein the covering includes a polymer.

32. The ureteral stent ofclaim 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 ofclaim 29, wherein the compressible portion includes a mesh construction.

34. The ureteral stent ofclaim 29, wherein the compressible portion includes a coil construction.

35. The ureteral stent ofclaim 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 ofclaim 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 ofclaim 37, wherein the covering is disposed on an outer surface of the compressible portion.

39. The ureteral stent ofclaim 37, wherein the covering is disposed on an inner surface of the compressible portion.

40. The ureteral stent ofclaim 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 ofclaim 37, wherein the compressible portion includes a mesh construction.

42. The ureteral stent ofclaim 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 ofclaim 43, wherein the compressible portion includes an outer covering.

45. The ureteral stent ofclaim 43, wherein the compressible portion includes an inner lining.

46. The ureteral stent ofclaim 43, wherein the compressible portion includes a mesh construction.

47. The ureteral stent ofclaim 43, wherein the compressible portion includes a coil construction.

48. The ureteral stent ofclaim 43, wherein the elongated portion includes a substantially continuous sidewall.

Images