Field of Invention

The present invention relates generally to implantable medical devices, and more particularly to stents, such as ureteral stents.

Background

The urinary tract has a pair of kidneys that connect to a bladder by ureteral passageways, and a urethra that extends from the bladder to the exterior of a patient. Urine is made by the kidneys, passed through the ureteral passageway, stored in the bladder and ultimately voided from the urethra. A urinary sphincter is positioned around the urethra near the base of the bladder to control the flow of urine from the bladder.

The ureteral passageways normally allow urine to pass from the kidney to the bladder by peristalsis. When the bladder fills with urine, the bladder compresses a segment of the ureteral passageway that passes through a wall of the bladder to prevent urine from going backwards from the bladder into the kidney. These passageways can become blocked by tumors, scar tissue or kidney stones thereby preventing normal urine flow, and the resulting high pressure within the kidneys can cause pain to the patient. To reopen a blocked ureteral passageway, a ureteral stent can be positioned in the patient. The stent holds the blockage in the passageway open, and allows the urine to bypass the blockage. This enables urine to flow from the kidney into the bladder, reduces kidney pressure, and reduces pain of the patient.

Summary of Invention

Provided is a ureteral stent for placement in a bladder, a kidney and a ureteral passageway connecting the bladder and the kidney. The ureteral stent includes a solid bladder portion free of a lumen positionable in the bladder, a tubular kidney portion positionable in the kidney and the ureteral passageway, and a tether connecting the bladder portion and the ureter portion to allow the bladder portion to float in the bladder and to allow a ureter orifice connecting the ureteral passageway to the bladder to move between a compressed state and an uncompressed state. By not having a lumen, the solid bladder portion allows the bladder to have a smaller diameter while maintaining a necessary uncoil force. The smaller diameter also allows the bladder portion to be inserted into a scope alongside a pusher tube, thereby avoiding loading the bladder portion onto a guidewire and simplifying the delivery process for the physician.

The foregoing and other features of the application are described below with reference to the drawings.

Brief Description of the Drawings

Fig. 1 is a schematic view of an exemplary stent positioned in a patient.

Fig. 2 is a schematic view of the stent of Fig. 1 .

Fig. 3 is a schematic view of another exemplary stent.

Fig. 4 is a schematic view of yet another exemplary stent.

Fig. 5 is a schematic view of still another exemplary stent.

Fig. 6 is a schematic view of a further exemplary stent.

Fig. 6A is a top view of a kidney portion of the stent of Fig. 6.

Figs. 7 and 8 are schematic views of still a further exemplary stent.

Fig. 9 is a schematic view of yet another exemplary stent.

Fig. 10 is a schematic view of a further exemplary stent.

Fig. 1 1 is a schematic view of a yet further exemplary stent.

Fig. 12 is a partial side view of still another exemplary stent.

Fig. 13 is a side view of the stent of Fig. 12.

Fig. 14 is a fragmentary cross-sectional view of an exemplary stent pusher and a guidewire.

Fig. 15 is a side view of the stent pusher of Fig. 14.

Fig. 16 is a side view of another exemplary stent pusher.

Fig. 17 is a schematic view of a guidewire being inserted into the patient.

Fig. 18 is a schematic view of the stent of Fig. 12 being positioned in the patient by the stent pusher of Fig. 14.

Fig. 19 is another schematic view of the stent of Fig. 12 being positioned in the patient by the stent pusher of Fig. 14.

Fig. 20 is still another schematic view of the stent of Fig. 12 being positioned in the patient by the stent pusher of Fig. 14. Fig. 21 is a schematic view of a kidney with a kidney portion of the stent inserted therein.

Fig. 22 is a schematic view of a ureteral passageway and bladder with a bladder portion of the stent inserted therein.

Detailed Description

The principles of the present application have particular application to ureteral stents for unblocking a ureteral passageway and thus will be described below chiefly in this context. It will, of course, be appreciated and also

understood that the principles of the application may be useful in other medical applications, such as other stent applications, for example biliary stents.

Referring now in detail to the drawings and initially to Fig. 1 , a pair of kidneys 10 and 12 and a bladder 14 of a patient are shown. The kidneys 10 and 12 are connected to the bladder 14 by respective ureteral passageways 16 and 18. The ureteral passageways 16 and 18 each include a portion extending into the bladder 14 that moves from an uncompressed state to compressed state and in a normal state only allows urine to pass from the kidneys 10 and 12 to the bladder 14 with the help of peristalsis of the ureter. When one of the

passageways 16 and 18 becomes blocked, for example by blockage from a kidney or ureteral stone, a ureteral stent may be positioned in the kidney 10, 12, ureteral passageway 16, 18 and bladder 14 to assist in opening the passageway 16, 18 to aid in the flow of urine.

The ureteral stent may be formed by a tube extending from the kidney 10, 12 to the bladder 14, the tube having a first helical end positioned in the kidney and a second helical end positioned in the bladder. Although such a stent allows urine to flow through and around the tube into the bladder, the tube may cause or contribute to patient discomfort and further medical problems. For example, the tube causes ureter orifices 20 and 22, which normally move from a compressed state to an uncompressed state, to remain open at all times allowing urine to flow from the bladder 14 to the kidney 10, 12 and the kidney 10, 12 to the bladder 14. Keeping the ureter orifices 20 and 22 open, thereby preventing the orifices 20 and 22 from compressing to prevent urine from flowing from the bladder 14 to the kidneys 10 and 12, may lead to urinary reflux and flank pain, for example. The bladder end of the ureteral stent also typically rests on or contacts a trigone 24 of the patient or wall of the bladder 14, causing blood in the urine, an intermittent strong urge to urinate, and painful bladder spasms resulting from the stent and therefore increased discomfort of the patient.

To minimize the footprint of the stent in the bladder 14 and/or near the ureteral orifices 20 and 22 and to allow urine to flow in a single direction from the kidneys 10 and 12 to the bladder 14 and not from the bladder 14 to the kidneys 10 and 12, thereby reducing the adverse effects associated with stents, an exemplary ureteral stent 50 is provided. As shown in Figs. 1 and 2, the stent 50 includes a bladder portion 52 positioned in the bladder 14, a kidney portion 54 positioned in the kidney 10 and ureteral passageway 16, and one or more tethers 56 coupling the bladder portion 52 to the kidney portion 54. The tether 56 may be a suitable thread, which is not limited to fibers, and may include, for example, a wire, such as a thin wire. Although not shown, it will be appreciated that the stent 50 may additionally or alternatively be positioned in the kidney 12 and ureteral passageway 18.

The bladder portion 52 is a resilient fixing member having any suitable shape, such as a tube that is curved in a flexible loop as shown in Fig. 2 when unrestrained to prevent the bladder portion 52 from migrating into the ureteral passageway 16. The bladder portion 52 is in an unrestrained shape when positioned in the bladder 14, and in a restrained shape, such as a substantially straight shape, when being positioned in the bladder 14. It will be appreciated that the bladder portion may be any suitable shape when unrestrained, such as J-shaped (Fig. 3), helical (Figs. 4 and 5), t-bar (Fig. 6), triangular (Fig. 9), circular (Fig. 10), etc. It will also be appreciated that the bladder portion may be made of any suitable material that does not irritate the patient's ureter tissue, such as urethane polymer, silicone, a thermoplastic, for example a thermoplastic polymer or elastomer, etc. It will also be appreciated that the suitable material may be a buoyant material to allow the bladder portion to float in the bladder, for example when the bladder is filled with urine, to allow the bladder portion to float off the trigone thereby decreasing irritation. The bladder portion 52 may include one or more openings 60 in a wall of the bladder portion that allow fluid to flow in/out of the bladder portion. The openings may be any suitable shape and size, such as a spiral, a circular opening, etc. The bladder portion 52 may also include at least one radiopaque element, such as a radiopaque band, and in the illustrated embodiment radiopaque bands 62 and 64 near first and second ends 66 and 68 of the bladder portion, respectively. The radiopaque bands may be any suitable radiopaque element provided to assist an operator in placing the stent 50.

Additionally or alternatively, it will be appreciated that the bladder portion 52 may be radiopaque to assist in positioning the stent. The bladder portion may also include a tip or ring 70 at the first end 66 having a stiffness greater than a stiffness of the rest of the bladder portion 52 to assist in the positioning of the stent 50.

Similar to the bladder portion 52, the kidney portion 54 has a resilient fixing portion 76, such as a tube in the form of a flexible loop when unrestrained to secure the kidney portion in the kidney 10. The resilient fixing portion 76 is in an unrestrained shape when positioned in the kidney, and in a restrained shape, such as a substantially straight shape, when being positioned in the kidney. It will be appreciated that the fixing portion may be any suitable shape when

unrestrained, such as J-shaped (Fig. 3), helical (Figs. 4 and 5), etc. It will also be appreciated that the bladder portion 52 and kidney portion 54 may have the same or different shapes when unrestrained, for example the bladder portion 52 and kidney portion 54 may both be a flexible loop as shown in Fig. 2, the bladder portion 52 or kidney portion 54 may be J-shaped and the other portion may be helical, etc.

The kidney portion 54 may be made of any suitable material that does not irritate the patient's ureter tissue, such as urethane polymer, silicone, a thermoplastic, for example a thermoplastic polymer or elastomer, etc. It will be appreciated that the kidney portion and bladder portion may be made of the same or different materials having the same or different durometers that are sufficient to allow for delivery reliability during placement while having tensile properties allowing for removal from the body. The kidney portion may have a durometer, for example, of 50 to 80 shore A and preferably 50 to 60 shore A, and the bladder portion may have a durometer, for example, of 25 to 50 shore A, and preferably 30 to 40 shore A. It will also be appreciated that the kidney portion, bladder portion, and/or tether may be made of one or more of an absorbable or non-absorbable material, a material to prevent calcification, a material to prevent incrustation, and may additionally or alternatively be impregnated with a suitable antibiotic and/or be drug-eluting.

In an embodiment, the bladder portion 52 has a softer durometer than the kidney portion 54 so that the bladder portion 52 is compliant with bladder contractions and to reduce irritation to the trigone 24. Additionally or

alternatively, the resilient fixing portion 76 of the kidney portion 54 is harder than a ureter portion 78 of the kidney portion 54. For example, the kidney portion 54 may have transition zones along its length going from a harder durometer at the fixing portion 76 to a softer durometer at the end of the ureter portion 78. It will also be appreciated that the bladder portion 52 and/or kidney portion 54 may be heat activated such that the portions are stiffer during placement and soften after placement in the body.

Referring again to the kidney portion 54, the kidney portion has the ureter portion 78, which may be a flexible tubular portion, configured to extend from the resilient fixing portion 76 in the kidney 10 into the ureteral passageway 16 to keep the passageway open, for example when there is a blockage between the kidney 10 and passageway 16. The kidney portion 54 may also include one or more openings 80 in a wall of the kidney portion 54 that allow fluid to flow in/out of the kidney portion 54. The openings may be any suitable shape and size, such as a spiral (Fig. 3), a circular opening, etc.

The kidney portion 54 also includes at least one radiopaque element, such as a radiopaque band, and in the illustrated embodiment radiopaque bands 82 and 84 near first and second ends 86 and 88 of the kidney portion 54, respectively, although it will be appreciated that the kidney portion 54 may additionally or alternatively be radiopaque to assist in placing the stent and identifying the stent on x-rays during placing. It will also be appreciated that the bladder portion 52 and/or kidney portion 54 may include measurement markers along their respective lengths to assist in positioning the stent 50. As noted above, the bladder portion 52 and kidney portion 54 are coupled together by one or more tethers 56. The tethers 56 have a thin flexible cross- section such that a transmural portion of the ureteral passageway, which passes through the bladder wall starting at the ureter opening and continuing through the thickness of the bladder 14, can clamp or remain in its normal state around the tethers 56. This allows for the single direction of urine flow from the kidney 10 to the bladder 14 to be maintained and prevents the flow or reflux of urine from the bladder 14 to the kidney 10. The tethers 56 may be any suitable tether having any suitable cross-sectional shape, such as a suitable suture made of cotton, a polymer such as nylon, etc. The tethers may also be any suitable length. For example, the tethers may be uniform in length for patients of varying sizes and the ureter portion 78 may be altered in length to accommodate patients of varying sizes and/or the suture lengths may be varied for patients of varying sizes. It will also be appreciated that the one or more tethers 56 may include one or more radiopaque marks along their lengths.

The tethers 56 are coupled to the second end 68 of the bladder portion and the second end 88 of the kidney portion in any suitable manner, for example by adhesive, knotting, etc. For example, as shown in Fig. 2, the tether 56 has an end received in an opening 92 at the second end 88 of the kidney portion 54 such that a portion of the tether 56 is outside the kidney portion 54 and a portion is inside the kidney portion 54. The portion of the tether 56 inside the kidney portion 54 extends to an inside of the bladder portion 52, where the tether extends out of an opening 72 in the bladder portion 52. Ends of the tether 56 are coupled together outside the bladder portion or the kidney portion, for example by tying the two ends together forming a knot. The excess tether created by the tying may then be cut off.

In an embodiment, a sleeve 74, such as a heat shrink, tape, UV adhesive, etc., is coupled to the second end 68 of the bladder portion to hold down the knot and excess tether to prevent or minimize irritation to the patient. It will be appreciated that by using the sleeve 74, the excess tether can be left longer than without the use of a sleeve 74 allowing the tether to lie down, reducing the thickness of the bladder portion 52. It will also be appreciated that the sleeve 74 may have radiopaque material on an external surface thereof to either replace the radiopaque band 64 or be used in conjunction with the band. Alternatively, the radiopaque band 64 may be positioned over the sleeve 74 or knot. The sleeve 74 is provided on the kidney portion 54 and/or the bladder portion 52 to cover knots on the outside of the kidney and/or bladder portion. It will be appreciated, however, that a stent may be provided having knots on the inside of the bladder portion and/or the kidney portion, in which case the sleeve may be omitted.

When the stent 50 is positioned in the body of the patient, the one or more tethers 56 extend from the ureteral passageway 16, through the ureter orifice 20 and into the bladder 14. The one or more tethers 56 allow the bladder portion 52 to anchor the kidney portion 54 to keep the ureter portion 78 in position in the ureteral passageway 16, for example to prevent the ureter portion 78 from curling up. The tether also allows the ureter orifice 20 to freely move between the compressed state and the uncompressed state to allow the ureter orifice to move to the compressed state when the bladder fills, thereby preventing urine from moving backwards. The tether also allows urine to pass in its normal direction from the kidney to the bladder. In this way, the tether prevents or minimizes urinary reflux, flank pain, patient discomfort, etc.

The one or more tethers 56 additionally allow the bladder portion 52 to move freely in the bladder 14, for example as the bladder fills with urine, to prevent the bladder portion 54 from irritating the trigone; to prevent or minimize bladder spasms, blood in the urine and a constant urge to urinate; and to avoid a rigid positioning of the stent that would hold the stent in one position over the trigone. The bladder portion thereby freely floats and/or dangles within the bladder, i.e. not held in a rigid position, and is constrained only by the length of the tether.

When being positioned, the kidney portion 54 and the bladder portion 52 are restrained, i.e. substantially straightened, to allow the portions to be navigated through the patient. It should be appreciated that for purposes of positioning, at least the ureter portion 78 of the kidney portion 54 has an inner diameter that is less than an inner diameter of the bladder portion 52. Once the kidney portion 54 is positioned and a guidewire withdrawn, the kidney portion moves to its unrestrained shape where the resilient fixing portion 76 is secured in the kidney 10 and the ureter portion 78 extends from the kidney 10 into the ureteral passageway 16 to keep the passageway open near the kidney.

Similarly, once the bladder portion 52 is positioned and the guidewire withdrawn, the bladder portion 52 moves to its unrestrained shape where the bladder portion 52 anchors the ureter portion 78 while allowing the ureter orifice 20 to freely move between the compressed state and uncompressed state.

Turning now to Figs. 3-10, exemplary embodiments of the ureteral stent is shown at 150, 250, 350, 450, 550, 650, 750 and 850. The ureteral stents 150, 250, 350, 450, 550, 650, 750 and 850 are substantially the same as the above- referenced ureteral stent 50, and consequently the same reference numerals but indexed by 100, 200, 300, 400, 500, 600, 700 and 800 respectively are used to denote structures corresponding to similar structures in the stents. In addition, the foregoing description of the stent 50 is equally applicable to the stent 150, 250, 350, 450, 550, 650, 750 and 850 except as noted below. Moreover, it will be appreciated upon reading and understanding the specification that aspects of the stents may be substituted for one another or used in conjunction with one another where applicable.

Referring now to Fig. 3, the bladder portion 152 is a J-shaped flexible tube when unrestrained that prevents the bladder portion 152 from migrating into the ureteral passageway 16. Similarly, the fixing portion 176 of the kidney portion 154 is a J-shaped flexible tube when unrestrained to secure the kidney portion in the kidney 10. The second end 168 of the bladder portion 152 and the second end 188 of the kidney portion 154 are each coupled to a tether 156 in any suitable manner. The kidney portion 154 includes one or more spiral openings 180 extending through the wall of the kidney portion and the bladder portion 152 includes one or more circular openings 160 extending through the wall of the bladder portion to allow fluid to flow in/out of the kidney portion 154 and bladder portion 152. It will be appreciated that the bladder portion 152 may additionally or alternatively include one or more spiral openings extending through the wall of the bladder portion and the kidney portion 154 may additionally or alternatively include one or more circular openings extending through the wall of the kidney portion. The kidney portion 154 has a diameter near the first end 186 that is larger than the diameter at the second end 188. For example, the diameter of the kidney portion may gradually taper down from the first end 186 to the second end 188. It will also be appreciated that the bladder portion 154 may have a diameter at the second end 168 that is larger than the diameter at the first end 166 of the bladder portion 152. Additionally, the diameter at the second end 168 of the bladder portion 152 may be substantially equal to or less than the diameter of the kidney portion at the second end 188, and the diameter at the first end 166 less than the diameter at the second end 168. Such a stent may be used as an endopyelotomy stent, providing a large diameter near the kidney for ureteral healing and a smaller diameter in the bladder for patient comfort.

Referring now to Figs. 4 and 5, the bladder portions 252 and 352 are helical flexible tubes when unrestrained that prevent the bladder portions 252 and 352 from migrating into the ureteral passageway. Similarly, the fixing portions 276 and 376 of the kidney portions 254 and 354 are helical flexible tubes when unrestrained to secure the kidney portions in the kidney. The helical flexible tube portions 252, 352, 276, 376 of the bladder portions 252 and 352 and kidney portions 254 and 354 may have any suitable number of coils. The second ends 268 and 368 of the bladder portions 252 and 352 and the second ends 288 and 388 of the kidney portions 254 and 354 are each coupled to a respective tether 256, 356 in any suitable manner, such as by an adhesive that is covered by a sleeve.

The ureter portions 278 and 378 of the kidney portions 254 and 354 have varying lengths for use with patients having ureteral passageways of varying sizes, such as pediatric lengths and sizes, adult lengths and sizes, etc. As shown, the ureter portion 278 has a length L1 for use with a patient having a ureteral passageway of a first length, and the ureter portion 378 has a length L2, which is greater than the length L1 , for use with a patient having a ureteral passageway of a second length greater than the first length. Additionally, the bladder portion 252 includes a substantially straightened portion 290 that is coupled to the tether, while the bladder portion 352 is formed without a straightened portion. It will be appreciated that the substantially straightened portion 290 may be included in the bladder portion 352 and not included in the bladder portion 252.

Referring now to Fig. 6, the bladder portion 452 is a t-bar that prevents the bladder portion 452 from migrating into the ureteral passageway. The kidney portion 454 is shown as a J-shaped flexible tube, although it will be appreciated the kidney portion may have any suitable shape as discussed above. Ends of a tubular portion 467 of the t-bar and the second end 488 of the kidney portion 454 are coupled to two suitable tethers in any suitable manner, for example, by knots on the outside of the t-bar and/or ureter portion 478 that are covered by a sleeve as discussed above or by knots on an inside of the ends of the tubular portion 467 and/or ureter portion 478.

The bladder portion 452 and/or kidney portion 454 may include one or more channels 480 along the length thereof that are provided to guide fluid, such as urine, out of the kidney 10 and into the bladder 14. For example, Fig. 6A shows a top view of the kidney portion 454 including three channels 480 that are circumferentially spaced around the kidney portion 454. The channels 480 may be evenly circumferentially spaced around the kidney portion 454 or spaced in any other suitable manner.

Referring now to Figs. 7 and 8, the stent 550 is formed by extruding the stent to form a flexible tubular member 600. Then at region 602, a section of the tubular member 600 is removed to form the tether 556. Before or after removing the section at region 602, geometric modifications, such as forming the fixing elements 552 and 554, adding retention notches, openings, etc. may be performed, for example by heat-forming, and surface edge softening may be performed.

Referring now to Fig. 9, the kidney portion 654 is a J-shaped flexible tube when unrestrained that secures the kidney portion 654 in the kidney 10. The bladder portion 652 is substantially triangular when unrestrained to prevent the bladder portion 652 from migrating into the ureteral passageway 16. The second end 668 of the bladder portion 652 and the second end 688 of the kidney portion 654 are each coupled to a tether 656 in any suitable manner. During positioning, the substantially triangular bladder portion is substantially straightened. Referring now to Fig. 10, the kidney portion 754 is a J-shaped flexible tube when unrestrained that secures the kidney portion 754 in the kidney 10. The bladder portion 752 is substantially circular and sized to be larger than the ureter orifice 20 to prevent the bladder portion 752 from migrating into the ureteral passageway 16. The bladder portion 752 includes a through-hole 767 extending therethrough and one or more openings 760 extending through the bladder portion. The bladder portion may also include a seat at one end of the through-hole 767 for an end of a pusher to seat against during placement.

Referring now to Fig. 1 1 , the kidney portion 854 is a J-shaped flexible tube when unrestrained that secures the kidney portion 854 in the kidney 10. Similarly, the bladder portion 852 is a J-shaped flexible tube when unrestrained that prevents the bladder portion 852 from migrating into the ureteral

passageway 16. The bladder portion 852 includes a first lumen 853 for the knot 857 to be disposed to prevent the knot from irritating the trigone area, for example, and a second lumen 855 for receiving a stent pusher assembly and guidewire. One or more openings 860 may be provided in the first and/or second lumens that allow fluid to flow in/out of the bladder portion. Similarly, the kidney portion may include a first lumen for a knot to be disposed and a second lumen for receiving a guidewire.

Turning now to Figs. 12 and 13, an exemplary embodiment of the stent is shown at 1050. The stent 1050 is substantially the same as the above- referenced stent 50, and consequently the same reference numerals but indexed by 1000 are used to denote structures corresponding to similar structures in the stents. In addition, the foregoing description of the stent 50 is equally applicable to the stent 1050 except as noted below.

The ureteral stent 1050 includes a solid bladder portion 1052 positionable in the bladder, a kidney portion 1054 positionable in the kidney and the ureteral passageway, and a tether 1056 connecting the bladder portion and the ureter portion. The tether may include markings, such as barium markings along its length or integrally woven into the tether to assist in placing the ureteral stent 1050.

The solid bladder portion 1052 could be used with kidney portion 1054 or any of the above described kidney portions. The solid bladder portion 1052, or monofilament bladder portion, does not have a lumen allowing the bladder portion 1052 to have a smaller diameter than bladder portions of traditional stents while maintaining the same or substantially the same uncoil force of the traditional bladder portions. The smaller diameter allows the bladder portion to be inserted into a rigid cystoscope alongside a pusher tube thereby avoiding loading the bladder portion onto a guidewire.

In an embodiment, the bladder portion has a diameter between .025 and .050 inches. In an embodiment, the bladder portion has a diameter between .025 and .035. In an embodiment the bladder portion has a diameter less than or equal to about .035 inches. For example, a bladder portion having a diameter of about .035 inches could be inserted into a lumen of the cystoscope alongside a 7 French stent pusher. The bladder portion may be made of any suitable material in any suitable way, such as by injection molding the bladder portion out of a polymer, such as polypropylene, heat forming, extrusion, etc. In an embodiment, the polymer can be molded with a radiopaque filler, such as barium or bismuth, allowing for precise control of the radiopaque filler in the polymer.

For example, the bladder portion may be made by taking a straight piece of monofilament polymer extrusion and wrapping and restraining the extrusion around a helical threaded rod. The extrusion, now in the form of a coil, and the threaded rod are then heated, such as by a heat gun, to a predetermined temperature, such as a temperature below a sub-melt temperature of the polymer. The coil and rod are then dipped in cold water to set the polymer molecules in the coil shape. A coil section can then be cut off of the larger coil to provide a 450 degree circular coil section. One end of the coil is flattened to form an eyelet flange and a hole is punched through the flattened flange to complete the formation of the eyelet distal end. Edges of the eyelet may then be sanded down. The opposite end of the coil is then inserted into a hypodermic tube having an inside diameter large enough to form a snug slip fit over the coil monofilament diameter and having a suitable length, such as 0.125 inches. The ends of the tether, which have been looped through the opening in the kidney portion, are inserted into the other end of the hypodermic tubing and advanced until they touch the coil. The hypodermic tube is then heated via a suitable heat source until the coil and tether ends melt, and the ends of the tether can be advanced further towards the coil forming a flow melt union. The tube can then be removed from the heat source and then removed from the tether, such as by a grinding technique to remove the tube wall allowing the tether to be removed. Alternatively, the tube could be replaced by impulse heated pliers with a lumen or an open and close impulse heated mold with a lumen.

The solid bladder portion 1052 has first and second ends 1066 and 1068. An eyelet 1 1 10 is formed at the first end 1066 for receiving a tether 1 1 12, such as a pullout suture for removing the ureteral stent 1050 from the patient. The eyelet may be integrally formed with the rest of the bladder portion, for example during molding, or may be attached to the first end 1066 of the bladder portion 1052 in any suitable manner, such as by flattening the monofilament and punching a hole through the end, melt flowing a loop with the bladder portion, insert molding a loop onto a head formed bladder portion, etc.

The second end 1068 is conical allowing first and second ends 1 130 and 1 132 of the tether 1056 to be coupled to the second end 1068, for example by a flow melt process, and have a smooth transition between the tether 1056 and the bladder portion 1052 to prevent irritation of the bladder. By attaching the tether 1056 to conical second end 1068, by reducing the diameter of the bladder portion 1052, and by being free of a lumen, the bladder portion 1052 can be delivered without a guidewire 1 1 14 running through a lumen, which could create friction or tangle with the tether in a lumen. Alternatively, the bladder portion 1052 could be formed with eyelets at the first and second ends and the tether 1056 could be secured to the eyelet at the second end, such as by knotting.

In another embodiment, the bladder portion could be formed by a suture having a larger diameter than the tether 1056, such as a diameter of .021 inches. The ends of the suture could be knotted, and the tether could be coupled to one knot, such as by tying or melting the sutures together, and the pull-out suture could be coupled to the other knot, such as by tying or melting the sutures together.

Referring now to the kidney portion 1054, the kidney portion may be tubular and is formed by a resilient fixing portion 1076 and a ureter portion 1078 extending from the resilient fixing portion. The kidney portion 1054 may include one or more radiopaque bands spaced along its length, such as bands 1084 near a second end 1088 of the kidney portion 1054. The kidney portion 1054 also includes an opening 1092 near the second end 1088 for receiving the tether 1056. One of the first or second ends 1 130 and 1 132 is inserted through the opening 1092 into a lumen of the kidney portion 1054 such that a portion of the tether is disposed inside the lumen and extends out an opening 1034 of the lumen at the second end 1088 and a portion of the tether 1056 extends outside the kidney portion 1054. The ends are then secured to the bladder portion 1052 as discussed above.

Turning now to Figs. 14 and 15, a stent pusher for delivering the ureteral stent 1050 into the kidney, ureteral passageway, and bladder is shown at reference numeral 1 140. The stent pusher 1 140 has a first end 1 142 configured to abut the second end 1088 of the kidney portion 1054 and a second end 1 144 opposite the first end that is manipulated by a surgeon during placement. The stent pusher 1 140 has a body 1 146 that may be any suitable shape, such as a tubular member, and a lumen 1 148 extending through the body 1 146. The stent pusher includes a tip 1 150 secured to the body 1 146 at the first end 1 142. The tip 1 150, which may be a stainless steel radiopaque tip, has a stiffness greater than the stiffness of the body 1 146. The tip 1 150 may be secured to the body 1 146 in any suitable manner or may be molded with the body 1 146.

The stent pusher 1 140 also includes a band 1 152 proximate the first end

1 142. The band may be a marker if using direct visualization or a radiopaque band if using fluoroscopy or direct visualization. The band is used to provide an indication to the surgeon of how far the stent pusher 1 140 should be advanced through the ureteral passageway. An end of the band closest to the first end 1 142 of the stent pusher 1 140 is a distance L3 from the end 1 142, which coincides with a distance L4 (Fig. 12), which is the distance of the tether 1056 from the second end 1068 of the bladder portion 1052 to the second end 1088 of the kidney portion 1054.

The stent pusher 1 140 has a diameter that is larger than the diameter of the kidney portion 1054 to prevent the stent pusher 1 140 from entering the lumen of the kidney portion 1054. For example, the stent pusher 1 140 may have a diameter of 7 French and the kidney portion has a diameter of 6 French. The bladder portion 1052 has a diameter less than the diameter of kidney portion 1054, as noted above, such that the diameters of the bladder portion 1052 and the stent pusher 1 140 combined are less than a diameter of a channel of the cystoscope.

Turning now to Fig. 16, an exemplary embodiment of the stent pusher is shown at 1240. The stent pusher 1240 is substantially the same as the above- referenced stent pusher 1 140, and consequently the same reference numerals but indexed by 100 are used to denote structures corresponding to similar structures in the pushers. In addition, the foregoing description of the stent pusher 1 140 is equally applicable to the stent pusher 1240 except as noted below.

The stent pusher 1240 has a first end 1242 configured to abut the second end 1088 of the kidney portion 1054 and a second end 1244 opposite the first end that is manipulated by a surgeon during placement. The stent pusher 1240 has a body 1246 and a lumen (not shown) extending through the body 1246. The stent pusher includes a tip 1250 and a band 1252.

The first end 1242 of the stent pusher has a first diameter greater than a second diameter of the second end of the stent pusher so that the bladder portion can move through the channel of the cystoscope alongside the second diameter portion while the first diameter portion can be moved through he channel alongside the tether and be sized to have sufficient column strength to push the kidney portion without buckling. For example, the first diameter of the stent pusher 1240 could be 6 French and the second diameter of the stent pusher 1240 could be 4 French. The stent pusher could gradually reduce its diameter from the first diameter to the second diameter or reduce its diameter rapidly.

Turning now to Figs. 17-22 in addition to Figs. 12-15, a method of placing the ureteral stent 1050 will be discussed. As shown in Fig. 17, the method begins with the guidewire 1 1 14 being inserted through the bladder 1014, into the ureteral passageway 1016 and into the kidney 1010. The kidney portion 1054 is then advanced over the guidewire 1 1 14 outside the patient. It will be

appreciated, however, that the kidney portion 1054 can be advanced over the guidewire 1 1 14 prior to the guidewire being positioned. As shown in Figs. 18 and 19, the stent pusher 1 140 is then advanced over and along the guidewire 1 1 14 until the tip 1 150 of the stent pusher abuts the second end 1088 of the kidney portion 1054. The stent pusher 1 140 is then advanced into the patient, thereby advancing the stent 1050 into the patient. Figs. 18 and 19 show the kidney portion 1054 substantially positioned in the ureteral passageway, with the second end 1088 of the kidney portion 1054 being positioned in the bladder 1014 near the ureter orifice 20.

As shown in Fig. 20, the stent pusher 1 140 is advanced further into the patient such that the tip 1 150 of the stent pusher 1 140 enters the ureteral passageway. The stent pusher 1 140 is advanced until the band 1 152 is aligned with or substantially aligned with the ureter orifice 1020, thereby indicating to the surgeon that the kidney portion 1054 is positioned in the kidney and ureteral passageway and that the bladder portion 1052 is positioned in the bladder. The stent pusher 1 140 and guidewire 1 1 14 can then be withdrawn from the patient, for example by removing or partially withdrawing the guidewire allowing the kidney portion 1 154 to move to the unrestrained position shown in Fig. 21 and then removing the stent pusher and guidewire either separately or

simultaneously. When unrestrained, the fixing portion 1076 secures the kidney portion 1054 in the kidney 1010, and the ureter portion 1078 extends from the kidney 1010 into the ureteral passageway 1016 to keep the passageway open. As shown in Fig. 22, when positioned the bladder portion 1052 floats in the bladder and the pullout suture 1 1 12 extends from the bladder outside the patient. Alternatively, the pullout suture 1 1 12 can be removed prior to placement.

As discussed above, the stent and stent pusher may be guided

fluoroscopically by the radiopaque elements on the stent and/or stent pusher, and/or by tracking markers on the stent and/or stent pusher. Additionally or alternatively, the stent may be positioned using a suitable endoscope.

Although certain embodiments have been shown and described, it is understood that equivalents and modifications falling within the scope of the appended claims will occur to others who are skilled in the art upon the reading and understanding of this specification.