CA1338031C - Ureteral stent system - Google Patents
Ureteral stent systemInfo
- Publication number
- CA1338031C CA1338031C CA000604092A CA604092A CA1338031C CA 1338031 C CA1338031 C CA 1338031C CA 000604092 A CA000604092 A CA 000604092A CA 604092 A CA604092 A CA 604092A CA 1338031 C CA1338031 C CA 1338031C
- Authority
- CA
- Canada
- Prior art keywords
- stent
- hook
- ureteral stent
- kidney
- patient
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M27/00—Drainage appliance for wounds or the like, i.e. wound drains, implanted drains
- A61M27/002—Implant devices for drainage of body fluids from one part of the body to another
- A61M27/008—Implant devices for drainage of body fluids from one part of the body to another pre-shaped, for use in the urethral or ureteral tract
Abstract
A ureteral stent has a main body that is soft and flexi-ble and a proximal hook portion which is stiffer to minimize explusion from the kidney.
Description
~ 338031 URETERAL STENT SYSTEM
Field of the Invention The present invention relates generally to ureteral stents. More particularly, it relates to an improved ureteral stent which is less prone to migration or expulsion from the kidney.
.
Background of the Invention Indwelling ureteral catheter stents or drainage tubes have been used to bypass ureteral obstructions or uretero-vaginal fistulas and to achieve and to maintain urinarydrainage between the kidney and the bladder. In the past, stents made of straight lengths of open end tubing have been used for this purpose and have provided good drainage for sustained periods of time. However, the use of such tubing has not been completely satisfactory. For example, in some instances, the tubing has migrated upward and in others it has been expelled from the kidney.
Various attempts were made to produce stents which did not have the problems which accompanied the use of such tubing. For example, stents were designed which had a hook at one end to prevent downward expulsion and which had a flange at the other end to make upward migration of the stent less likely. Another approach was to provide the body of the stent with sharply pointed barbs which were designed to prevent both downward migration and expulsion from the kidney. However, such barbs increased the diameter of the stent making it more difficult to insert.
In the Finney U.S. Patent No. 4,212,304, issued July 15, 1979, and the Finney U.S. Patent No. 4,307,723, issued December 29, 1981, ureteral stents are disclosed which are soft silicone members which have hooks at each end and which are surprisingly effective in preventing both upward migra-tion and downward expulsion. In normal use the proximal hook is placed in the lower calyx of the kidney or the renal pelvis of the patient and the distal hook is placed in the bladder. The stent then provides a passage for urine from the kidney to the bladder. The Pinney stents are widely accepted because they work well; they are well tolerated by the patients; and they can be easily introduced both endo-scopically and during open surgery.
In the Densow U.S. Patent No. 4,610,657, a modification of a Finney-type stent is disclosed which has a hook at each end, a central lumen and a reduced opening at the proximal end. The stent can be placed in a patient using a pusher wire or by the known over-the-wire technique. The guidewire system disclosed for use with the Densow stent comprises two separate guidewires. One of the wires is the pusher wire.
It is smaller in diameter than the lumen of the stent, but has a proximal end which is larger than the reduced opening at the proximal end. It is used to push the stent in place when no obstructions are encountered. The other wire is used when an obstruction is encountered. It is smaller in diameter than both the first wire and the reduced opening in the stent. When an obstruction is encountered the stent and the pu~her wire are withdrawn and the pu~her wire is removed. The smaller diameter wire is inserted in the lumen of the stent and the stent and wire reinserted; the leading S end of the smaller wire is then advanced out the reduced opening in the proximal end and maneuvered past the obstruc-tion. The stent is then run over the wire past the obstruction. Once the leading end of the stent is past the obstruction, the stent is pushed into place with a stent pusher.
In the Carter U.S. Patent No. 4,713,0~9 a guide system is disclosed which can be used with either the Finney or Densow type stents. The guide system is comprised of a relatively flexible outer member with a flexible forgiving tip and a relatively rigid movable core which fits within the outer member. Methods of inserting stents using that guide system are described in the Carter patent.
The Finney stent and the Densow modification are both made entirely of relatively soft material, sucb a~ silicone rubber, and are widely accepted because they are well tole-rated, they do not migrate upwardly and they do not cause patient discomfort. However, on occasion such stents may be expelled downwardly out of the kidney. The Finney patent suggests that the hooks could be reinforced by the incor-poration of "plastic, fabric, metal or other suitablematerial" to make them less flexible and more resistant to migration but the incorporation of such foreign materials can detract from the otherwise good memory of the stent material.
4 1 33803~
Stents have been made of stiffer less flexible material, such as polyethylene, in efforts to reduce expulsion of migration, but those stents have not been as well accepted because a stent made of stiffer material can cause bladder irritation and other patient discomfort.
It would be desirable to have a stent that had all the advantages of the Finney and the Densow stents and which, in addition, would have a greater resistance to being expelled from the kidney.
Brief Summary of the Invention It is an object of the present invention to disclose an improved ureteral stent which resists migration and expulsion from the kidney.
The stent of the present invention differs from the described prior art stents in that it comprises a soft flexible main body, and a nonreinforced hook portion connected to the body for placement in the kidney of a patient to reduce the likelihood of expulsion or migration of the stent, and being stiffer than the main body and formed from a material having a memory at body temperature sufficient to resume a hook shape when the hook portion is straightened with a straightening force, placed in the kidney of the patient, and the straightening force is removed.
The stent of the present invention is preferably made of a material or materials having two different stiffnesses or durometers. The durometer of the proximal hook portion which curls into the kidney is relatively stiff, preferably about 95 Shore A, and that of the remainder of the stent is more flexible and soft, preferably about 50 to about 85 Shore A.
The stent of the present invention may take a variety of forms, including, a Finney type stent with a closed proximal end or an open proximal end. The guide system preferred for use with the stent of the present invention is that of the Carter patent.
According to another aspect of the present invention, there is provided an ureteral stent comprising a hook at one end portion of the stent for placement in a kidney of a patient and a hook at another end portion of the stent for placement in a bladder of the patient, wherein the hook at said one end portion is formed from a stiffer material than the hook at said another end portion.
The above stated and other objects and advantages of the invention will be apparent from the description which follows:
Description of the Drawinqs Fig. 1 is an elevational view of a kit which includes one embodiment of a stent of the present invention and a guide system;
Fig. 2 is an elevational view showing the stent and guide system of Fig. 1 with the hooks of the stent straightened;
Fig. 3 is an enlarged sectional view of the proximal end of the stent of Fig. 2;
Fig. 4 is a view similar to Fig. 2 but showing the unreinforced leading end of the guide system extending out of the stent;
Fig. 5 is a partial view, in section 1, of the unreinforcing leading end shown in Fig. 4;
Fig. 6 is an enlarged sectional view showing the junction of the stiffer proximal hook portion and the remainder of the stent of Fig. l;
Fig. 7 is an elevational view of another emboA;r^nt of the stent of the present invention; and Fig. 8 is an enlarged sectional view of the distal end of the stent of Fig. 7.
~'' ~f :i ,, .~
i-- 1 338031 Description of the Preferred Embodiment In the preferred embodiment of the invention shown in Fig. 1, there is seen a stent 10 which is an elongated ,. .
tubular member having a proximal end 11 and a distal end 12. Portions adjacent each of the ends 11 and 12 of the stent 10 are formed and set in the shape of hooks 13 and 14. In the stent 10 both the proximal end 11 and the distal end 12 as shown are open. In some cases, it may be preferred to supply the stent 10 with the distal end 12 closed and an opening (not shown) in the side wall which is sized to receive the guide system.
In the drawing the hook portions 13 and 14 are shown extending in the same direction. However, the hook portions 13 and 14 preferably extend in opposite directions so that when the stent 10 is used as an indwelling ureteral stent the proximal end 11 can hook into the lower calyx of the kidney or renal pelvis while the distal end 12 curves into the bladder.
The stent 10 includes a relatively straight intermediate section 15 which extends between the proximal hook portion 13 and the distal hook portion 14.
Referring now to Figs. 1 to 5, it can be seen that the stent 10 has radial drainage passages 16 which connect the lumen 17 of the stent 10 to the outside and permit inside/
outside drainage. The drainage passages 16 are preferably spirally located about 5 centimeters apart on both sides of the straight section 15. There are similar openings 18 in the wall of the proximal hook portion 13. The stent 10 also has increment markings 19 every 5 cms and an axial ring 20 which signals the physician to stop advancing the stent when the ring reaches the ureteral orifice.
As seen best in Figs. 3 and 5, the proximal end ll has an externally tapered tip lla which eases the progress of the stent lO through the ureter of the patient and assists in the reduction of tissue trauma as the stent is advanced through the urinary tract. The opening 21 of the tip lla is about .041 inches so that the stent lO can be advanced over a standard .038 inch guidewire for a standard retrograde, over-the-wire placement.
The ureteral stent lO of the present invention differs from the prior art stents in that the proximal hook portion 13 is made of a homogenous, thermoplastic material which is substantially stiffer than the soft, more flexible material from which the remainder of the stent is formed. For example, the main body lOa of stent 10 is made of a soft flexible material, preferably polyurethane, which has a durometer between about 50 and about 85 Shore 'A' to which barium sulfate has been added as the radiopaque agent. In contrast, the proximal hook portion is made of a stiffer less flexible material, also preferably polyurethane, having a durometer of about 95 Shore 'A'. The higher durometer material of the proximal hook portion 13 forms a more secure curl into the kidney thus further minimizing migration or explusion.
The hook portion 13 and main body lOa of the stent lO
can be joined together in a number of ways. The preferred method comprises modifying the ends of the proximal hook portion 13 and the main body of the stent lO to be joined by ! 3381)31 enlarging their internal diameters and placing the thus modified ends on a wire in a mold (neither shown) about 1/8 inch apart. The gap between the ends of the proximal hook portion 13 and the remainder of the stent 10 is then filled with a polyurethane material 22 which is molded about the ends and the wire and cured to join the two pieces together as seen in Fig. 6 to form an integral stent. The stent 10 is then removed from the mold and the wire removed from lumen 17 of the stent.
Referring back to Fig. 1, there can be seen the pre-ferred guide system of the prèsent lnvention. ~s seen therein, the guide system comprises a stent pusher 23, a relatively large diameter hollow guide member 24, which is Teflon coated and sized to fit in the lumen 17 of the stent 10; and a longer, smaller diameter core 25 which is sized to fit within the lumen 24a of the hollow guide member 24.
To properly place the 8tent 10 in a patient, the physician first properly places a cystoscope in the patient. The guide system comprising the relatively large diameter hollow guide member 24 ~itb the core 2~ in the lumen 24a (as seen in Fig. 2) is next passed up the urethra. As the guide system enters the ureter, the physician advances and retracts the movable inner core 25 ~as seen in Figs. 3, 4 and 5) to regulate the softness or firmness of the tip lla. Adjusting the tip lla will aid in negotiating tortuous ureters and bypassing obstructions. As the leading end of the guide system enters the kidney, the physician can move the inner core 25 so the tip lla of the guide system gently o- firmly enters the calyces. The physician then threads the stent 10 over the guide system to t 33803 1 straighten the proximal and distal hook portions 13 and 14, respectively, as seen in Fig. 2. Using the stent pusher 23, the stent 10 is advanced over the guide system. The tapered .. ..
tip lla of the stent 10 eases its way along the guide S system, assisting in the reduction of trauma to the tissue of the ureter. The spiral pattern of holes 16 placed along the shaft of the stent 10 helps to minimize kinking as the stent advances over the guide member 24. The physician can verify that the hooks form in the appropriate directions when the guide wire is removed by observing the position of a medial line (not shown) on the stent. The physician measures the progress of the stent 10 by using the increment markings 19. Also, the physician can use the increment markings 19 to define the position of obstructions. The lS physician also can use the axial ring 20 to aid in effectiveIy placing the distal hook 14 within the bladder.
As soon as the guide system is retracted from the proximal end, the proximal hook portion 13 curls and positions itself in the kidney. The stronger durometer of the proximal hook portion 13 minimizes movement as the guide system is retracted from the lumen 17 of the stent. As the guide system is retracted further down the shaft, the coating on the guide member aids in its smooth removal. As the guide system leaves the distal hook portion 14, the soft distal hook resumes its shape. The contour and softness of the distal hook portion 14 permit it to rest comfortably within the bladder and minimizes bladder irritation. The physician then removes the cystoscope and the stenting procedure is complete.
- ~ 338031 When it is desired to replace an indwelling stent of the type shown in Fig. 1 to 6, the stent is first cystoscopi-cally visualized and then a foreign body forceps or a retractable type stone basket (neither shown) is advanced S through the cystoscope to catch the end 12 of the stent and to retract the stent 10 from the patient.
A second embodiment of the stent of the present invention is shown in Figs. 7 and 8. It differs from the embodiment of Fiqs. 1 to 6 only in that the distal hook portion 14 includes a tip 14a which is a cylinder 26 of magnetically attractable material. The cylinder 26 has a central bore 27 through which the guide system can be intro-duced and is best seen in Fig. 8. The stent of Figs. 7 and 8 can be removed with a retrieving catheter (not shown) equipped with a magent. It i~ disclosed and claimed in U.S. patent N 4,790,809 issued on December 13, 1988.
The stent 10 is preferably formed by extruding a length of tubing of the desired size and durometer to form the main body lOa. The length of tubing is then placed in a form and heated to shape the distal hook portion 14. The openings 16 and 18 may be formed in the main body lOa at any step of the process by piercing the wall of the tubing with a flattened, sharpened hole cutter of the desired size or by use of a laser or any other conventional means. The proximal hook portion 13 is extruded of a stiffer material. The hook and tapered open proximal end lla are formed in a heated mold.
The proximal hook portion 13 is then joined to the main body lOa as described.
The material of which the stent 10 is preferably made is an extrudable polyurethane which can be characterized as being an essentially linear, segmented aliphatic polyurethane elastomer. The polyurethane is composed of three repeating units, a diol, a diisocyanate and a macroglycol. The relationship of these three repeating units to each other determine the physical characteristics of the polymer including the durometer. For example, the soft, flexible polyurethane for the main body lOa which has a durometer of about 80 Shore A has a ratio of diol to macroglycol of one to one. Since the diisocyanate links both the diol and the macroglycol there are two diisocyanates for each diol or macroglycol in this example. The stiffer polyurethanes having a durometer of about 95 Shore 'A' (60 Shore 'D') have a ratio of diol to glycol of 1.3 to 0.7 and a number of diiocyanate units that is greater than or equal to the combined number of diols and macroglycols. This polyurethane material being aliphatic and polyether based with 100% urethane linkages in the molecular backbone exhibits superior flexural life and a high degree of biocompatibility. In addition, the polymer if homogenous and not contaminated with reinforcing fibers or fillers possesses good memory and enables the proximal hook portion 13 to quickly regain its hook shape at body temperature (98.6F). These polymers are available from Thermedics, Inc. of Woburn, Massachusetts under the trade name TECOELEX. The preparation of the polymers is described in U.S. Patents Nos. 4,447,590 and 4,523,005.
The polyuLethane material that is used to make the junction 22 ~seen best in Fig. 6) is a moldable polyurethane that forms good secure bonds with both the soft material of *Trademark the main body 10a and the stiffer material of the proximal hook portion 13. Polyurethanes that can be used include the polyurethane used to make the proximal hook 13 as well as other known polyurethane adhesives.
The preferred hollow guide member 24 is a tubular member having a relatively flexible forg-iving tip leading end 24b which is closed. The preferred guide member 24 has an OD of about 0.032 inches; ID of about 0.016 inches and it is formed of stainless steel coated with Teflon.*
The core 25 is sized to fit within the lumen 24a and is more rigid than the guide member 24. It may be formed of stainless steel wire. It preferably has an OD of about 0.013 inches. The length of the core 25 should be greater than that of the guide member 24 so that the handle 25a will protrude from the guide member 24 when the leading end 25b is seated against the closed end of the lumen 24a of the guide member 24. The handle 25a is used to advance or retract the core 25.
The stent of the present invention will normally be supplied in a kit comprising a stent 10 and the guide system. ~owever, the stent 10 also may be sold separately for use with a standard 0.038 inch guidewire.
In the preferred embodiment described and shown in the drawing, the proximal and distal end portions of the stent are both in the form of gently curved, closed hooks. ~ow-ever, it is to be understood that the term "hook" is intend-ed to include other functionally equivalent shapes such as coils which prevent migration and do not increase the effec-tive outer diameter of the stent, or complicate its method of introduction.
*Trademark , - ~
The preferred method Q~ preparing the stent of the present invention is that ~hich has been described. How-ever, a stent might be prepared by other methods such as extending and forming a stent extirely of soft, flexible material and thereafter stiffening the proximal hook by leaching plasticizer therefrom or coating it with more material and increasing its thickness. Likewise, use of connectors to joining the proximal hook portion to the main body of the stent is less desirable since the connectors may increase the outside diameter of the stent or reduce the size of the lumen or fail.
It will be readily apparent to those skilled in the art that a number of modifications and changes can be made with-out departing from the spirit of the invention. Therefore, it is to be understood thalt the scope of the invention is not be be limited by the foregoin,g description, but only by the claims. ---'
Field of the Invention The present invention relates generally to ureteral stents. More particularly, it relates to an improved ureteral stent which is less prone to migration or expulsion from the kidney.
.
Background of the Invention Indwelling ureteral catheter stents or drainage tubes have been used to bypass ureteral obstructions or uretero-vaginal fistulas and to achieve and to maintain urinarydrainage between the kidney and the bladder. In the past, stents made of straight lengths of open end tubing have been used for this purpose and have provided good drainage for sustained periods of time. However, the use of such tubing has not been completely satisfactory. For example, in some instances, the tubing has migrated upward and in others it has been expelled from the kidney.
Various attempts were made to produce stents which did not have the problems which accompanied the use of such tubing. For example, stents were designed which had a hook at one end to prevent downward expulsion and which had a flange at the other end to make upward migration of the stent less likely. Another approach was to provide the body of the stent with sharply pointed barbs which were designed to prevent both downward migration and expulsion from the kidney. However, such barbs increased the diameter of the stent making it more difficult to insert.
In the Finney U.S. Patent No. 4,212,304, issued July 15, 1979, and the Finney U.S. Patent No. 4,307,723, issued December 29, 1981, ureteral stents are disclosed which are soft silicone members which have hooks at each end and which are surprisingly effective in preventing both upward migra-tion and downward expulsion. In normal use the proximal hook is placed in the lower calyx of the kidney or the renal pelvis of the patient and the distal hook is placed in the bladder. The stent then provides a passage for urine from the kidney to the bladder. The Pinney stents are widely accepted because they work well; they are well tolerated by the patients; and they can be easily introduced both endo-scopically and during open surgery.
In the Densow U.S. Patent No. 4,610,657, a modification of a Finney-type stent is disclosed which has a hook at each end, a central lumen and a reduced opening at the proximal end. The stent can be placed in a patient using a pusher wire or by the known over-the-wire technique. The guidewire system disclosed for use with the Densow stent comprises two separate guidewires. One of the wires is the pusher wire.
It is smaller in diameter than the lumen of the stent, but has a proximal end which is larger than the reduced opening at the proximal end. It is used to push the stent in place when no obstructions are encountered. The other wire is used when an obstruction is encountered. It is smaller in diameter than both the first wire and the reduced opening in the stent. When an obstruction is encountered the stent and the pu~her wire are withdrawn and the pu~her wire is removed. The smaller diameter wire is inserted in the lumen of the stent and the stent and wire reinserted; the leading S end of the smaller wire is then advanced out the reduced opening in the proximal end and maneuvered past the obstruc-tion. The stent is then run over the wire past the obstruction. Once the leading end of the stent is past the obstruction, the stent is pushed into place with a stent pusher.
In the Carter U.S. Patent No. 4,713,0~9 a guide system is disclosed which can be used with either the Finney or Densow type stents. The guide system is comprised of a relatively flexible outer member with a flexible forgiving tip and a relatively rigid movable core which fits within the outer member. Methods of inserting stents using that guide system are described in the Carter patent.
The Finney stent and the Densow modification are both made entirely of relatively soft material, sucb a~ silicone rubber, and are widely accepted because they are well tole-rated, they do not migrate upwardly and they do not cause patient discomfort. However, on occasion such stents may be expelled downwardly out of the kidney. The Finney patent suggests that the hooks could be reinforced by the incor-poration of "plastic, fabric, metal or other suitablematerial" to make them less flexible and more resistant to migration but the incorporation of such foreign materials can detract from the otherwise good memory of the stent material.
4 1 33803~
Stents have been made of stiffer less flexible material, such as polyethylene, in efforts to reduce expulsion of migration, but those stents have not been as well accepted because a stent made of stiffer material can cause bladder irritation and other patient discomfort.
It would be desirable to have a stent that had all the advantages of the Finney and the Densow stents and which, in addition, would have a greater resistance to being expelled from the kidney.
Brief Summary of the Invention It is an object of the present invention to disclose an improved ureteral stent which resists migration and expulsion from the kidney.
The stent of the present invention differs from the described prior art stents in that it comprises a soft flexible main body, and a nonreinforced hook portion connected to the body for placement in the kidney of a patient to reduce the likelihood of expulsion or migration of the stent, and being stiffer than the main body and formed from a material having a memory at body temperature sufficient to resume a hook shape when the hook portion is straightened with a straightening force, placed in the kidney of the patient, and the straightening force is removed.
The stent of the present invention is preferably made of a material or materials having two different stiffnesses or durometers. The durometer of the proximal hook portion which curls into the kidney is relatively stiff, preferably about 95 Shore A, and that of the remainder of the stent is more flexible and soft, preferably about 50 to about 85 Shore A.
The stent of the present invention may take a variety of forms, including, a Finney type stent with a closed proximal end or an open proximal end. The guide system preferred for use with the stent of the present invention is that of the Carter patent.
According to another aspect of the present invention, there is provided an ureteral stent comprising a hook at one end portion of the stent for placement in a kidney of a patient and a hook at another end portion of the stent for placement in a bladder of the patient, wherein the hook at said one end portion is formed from a stiffer material than the hook at said another end portion.
The above stated and other objects and advantages of the invention will be apparent from the description which follows:
Description of the Drawinqs Fig. 1 is an elevational view of a kit which includes one embodiment of a stent of the present invention and a guide system;
Fig. 2 is an elevational view showing the stent and guide system of Fig. 1 with the hooks of the stent straightened;
Fig. 3 is an enlarged sectional view of the proximal end of the stent of Fig. 2;
Fig. 4 is a view similar to Fig. 2 but showing the unreinforced leading end of the guide system extending out of the stent;
Fig. 5 is a partial view, in section 1, of the unreinforcing leading end shown in Fig. 4;
Fig. 6 is an enlarged sectional view showing the junction of the stiffer proximal hook portion and the remainder of the stent of Fig. l;
Fig. 7 is an elevational view of another emboA;r^nt of the stent of the present invention; and Fig. 8 is an enlarged sectional view of the distal end of the stent of Fig. 7.
~'' ~f :i ,, .~
i-- 1 338031 Description of the Preferred Embodiment In the preferred embodiment of the invention shown in Fig. 1, there is seen a stent 10 which is an elongated ,. .
tubular member having a proximal end 11 and a distal end 12. Portions adjacent each of the ends 11 and 12 of the stent 10 are formed and set in the shape of hooks 13 and 14. In the stent 10 both the proximal end 11 and the distal end 12 as shown are open. In some cases, it may be preferred to supply the stent 10 with the distal end 12 closed and an opening (not shown) in the side wall which is sized to receive the guide system.
In the drawing the hook portions 13 and 14 are shown extending in the same direction. However, the hook portions 13 and 14 preferably extend in opposite directions so that when the stent 10 is used as an indwelling ureteral stent the proximal end 11 can hook into the lower calyx of the kidney or renal pelvis while the distal end 12 curves into the bladder.
The stent 10 includes a relatively straight intermediate section 15 which extends between the proximal hook portion 13 and the distal hook portion 14.
Referring now to Figs. 1 to 5, it can be seen that the stent 10 has radial drainage passages 16 which connect the lumen 17 of the stent 10 to the outside and permit inside/
outside drainage. The drainage passages 16 are preferably spirally located about 5 centimeters apart on both sides of the straight section 15. There are similar openings 18 in the wall of the proximal hook portion 13. The stent 10 also has increment markings 19 every 5 cms and an axial ring 20 which signals the physician to stop advancing the stent when the ring reaches the ureteral orifice.
As seen best in Figs. 3 and 5, the proximal end ll has an externally tapered tip lla which eases the progress of the stent lO through the ureter of the patient and assists in the reduction of tissue trauma as the stent is advanced through the urinary tract. The opening 21 of the tip lla is about .041 inches so that the stent lO can be advanced over a standard .038 inch guidewire for a standard retrograde, over-the-wire placement.
The ureteral stent lO of the present invention differs from the prior art stents in that the proximal hook portion 13 is made of a homogenous, thermoplastic material which is substantially stiffer than the soft, more flexible material from which the remainder of the stent is formed. For example, the main body lOa of stent 10 is made of a soft flexible material, preferably polyurethane, which has a durometer between about 50 and about 85 Shore 'A' to which barium sulfate has been added as the radiopaque agent. In contrast, the proximal hook portion is made of a stiffer less flexible material, also preferably polyurethane, having a durometer of about 95 Shore 'A'. The higher durometer material of the proximal hook portion 13 forms a more secure curl into the kidney thus further minimizing migration or explusion.
The hook portion 13 and main body lOa of the stent lO
can be joined together in a number of ways. The preferred method comprises modifying the ends of the proximal hook portion 13 and the main body of the stent lO to be joined by ! 3381)31 enlarging their internal diameters and placing the thus modified ends on a wire in a mold (neither shown) about 1/8 inch apart. The gap between the ends of the proximal hook portion 13 and the remainder of the stent 10 is then filled with a polyurethane material 22 which is molded about the ends and the wire and cured to join the two pieces together as seen in Fig. 6 to form an integral stent. The stent 10 is then removed from the mold and the wire removed from lumen 17 of the stent.
Referring back to Fig. 1, there can be seen the pre-ferred guide system of the prèsent lnvention. ~s seen therein, the guide system comprises a stent pusher 23, a relatively large diameter hollow guide member 24, which is Teflon coated and sized to fit in the lumen 17 of the stent 10; and a longer, smaller diameter core 25 which is sized to fit within the lumen 24a of the hollow guide member 24.
To properly place the 8tent 10 in a patient, the physician first properly places a cystoscope in the patient. The guide system comprising the relatively large diameter hollow guide member 24 ~itb the core 2~ in the lumen 24a (as seen in Fig. 2) is next passed up the urethra. As the guide system enters the ureter, the physician advances and retracts the movable inner core 25 ~as seen in Figs. 3, 4 and 5) to regulate the softness or firmness of the tip lla. Adjusting the tip lla will aid in negotiating tortuous ureters and bypassing obstructions. As the leading end of the guide system enters the kidney, the physician can move the inner core 25 so the tip lla of the guide system gently o- firmly enters the calyces. The physician then threads the stent 10 over the guide system to t 33803 1 straighten the proximal and distal hook portions 13 and 14, respectively, as seen in Fig. 2. Using the stent pusher 23, the stent 10 is advanced over the guide system. The tapered .. ..
tip lla of the stent 10 eases its way along the guide S system, assisting in the reduction of trauma to the tissue of the ureter. The spiral pattern of holes 16 placed along the shaft of the stent 10 helps to minimize kinking as the stent advances over the guide member 24. The physician can verify that the hooks form in the appropriate directions when the guide wire is removed by observing the position of a medial line (not shown) on the stent. The physician measures the progress of the stent 10 by using the increment markings 19. Also, the physician can use the increment markings 19 to define the position of obstructions. The lS physician also can use the axial ring 20 to aid in effectiveIy placing the distal hook 14 within the bladder.
As soon as the guide system is retracted from the proximal end, the proximal hook portion 13 curls and positions itself in the kidney. The stronger durometer of the proximal hook portion 13 minimizes movement as the guide system is retracted from the lumen 17 of the stent. As the guide system is retracted further down the shaft, the coating on the guide member aids in its smooth removal. As the guide system leaves the distal hook portion 14, the soft distal hook resumes its shape. The contour and softness of the distal hook portion 14 permit it to rest comfortably within the bladder and minimizes bladder irritation. The physician then removes the cystoscope and the stenting procedure is complete.
- ~ 338031 When it is desired to replace an indwelling stent of the type shown in Fig. 1 to 6, the stent is first cystoscopi-cally visualized and then a foreign body forceps or a retractable type stone basket (neither shown) is advanced S through the cystoscope to catch the end 12 of the stent and to retract the stent 10 from the patient.
A second embodiment of the stent of the present invention is shown in Figs. 7 and 8. It differs from the embodiment of Fiqs. 1 to 6 only in that the distal hook portion 14 includes a tip 14a which is a cylinder 26 of magnetically attractable material. The cylinder 26 has a central bore 27 through which the guide system can be intro-duced and is best seen in Fig. 8. The stent of Figs. 7 and 8 can be removed with a retrieving catheter (not shown) equipped with a magent. It i~ disclosed and claimed in U.S. patent N 4,790,809 issued on December 13, 1988.
The stent 10 is preferably formed by extruding a length of tubing of the desired size and durometer to form the main body lOa. The length of tubing is then placed in a form and heated to shape the distal hook portion 14. The openings 16 and 18 may be formed in the main body lOa at any step of the process by piercing the wall of the tubing with a flattened, sharpened hole cutter of the desired size or by use of a laser or any other conventional means. The proximal hook portion 13 is extruded of a stiffer material. The hook and tapered open proximal end lla are formed in a heated mold.
The proximal hook portion 13 is then joined to the main body lOa as described.
The material of which the stent 10 is preferably made is an extrudable polyurethane which can be characterized as being an essentially linear, segmented aliphatic polyurethane elastomer. The polyurethane is composed of three repeating units, a diol, a diisocyanate and a macroglycol. The relationship of these three repeating units to each other determine the physical characteristics of the polymer including the durometer. For example, the soft, flexible polyurethane for the main body lOa which has a durometer of about 80 Shore A has a ratio of diol to macroglycol of one to one. Since the diisocyanate links both the diol and the macroglycol there are two diisocyanates for each diol or macroglycol in this example. The stiffer polyurethanes having a durometer of about 95 Shore 'A' (60 Shore 'D') have a ratio of diol to glycol of 1.3 to 0.7 and a number of diiocyanate units that is greater than or equal to the combined number of diols and macroglycols. This polyurethane material being aliphatic and polyether based with 100% urethane linkages in the molecular backbone exhibits superior flexural life and a high degree of biocompatibility. In addition, the polymer if homogenous and not contaminated with reinforcing fibers or fillers possesses good memory and enables the proximal hook portion 13 to quickly regain its hook shape at body temperature (98.6F). These polymers are available from Thermedics, Inc. of Woburn, Massachusetts under the trade name TECOELEX. The preparation of the polymers is described in U.S. Patents Nos. 4,447,590 and 4,523,005.
The polyuLethane material that is used to make the junction 22 ~seen best in Fig. 6) is a moldable polyurethane that forms good secure bonds with both the soft material of *Trademark the main body 10a and the stiffer material of the proximal hook portion 13. Polyurethanes that can be used include the polyurethane used to make the proximal hook 13 as well as other known polyurethane adhesives.
The preferred hollow guide member 24 is a tubular member having a relatively flexible forg-iving tip leading end 24b which is closed. The preferred guide member 24 has an OD of about 0.032 inches; ID of about 0.016 inches and it is formed of stainless steel coated with Teflon.*
The core 25 is sized to fit within the lumen 24a and is more rigid than the guide member 24. It may be formed of stainless steel wire. It preferably has an OD of about 0.013 inches. The length of the core 25 should be greater than that of the guide member 24 so that the handle 25a will protrude from the guide member 24 when the leading end 25b is seated against the closed end of the lumen 24a of the guide member 24. The handle 25a is used to advance or retract the core 25.
The stent of the present invention will normally be supplied in a kit comprising a stent 10 and the guide system. ~owever, the stent 10 also may be sold separately for use with a standard 0.038 inch guidewire.
In the preferred embodiment described and shown in the drawing, the proximal and distal end portions of the stent are both in the form of gently curved, closed hooks. ~ow-ever, it is to be understood that the term "hook" is intend-ed to include other functionally equivalent shapes such as coils which prevent migration and do not increase the effec-tive outer diameter of the stent, or complicate its method of introduction.
*Trademark , - ~
The preferred method Q~ preparing the stent of the present invention is that ~hich has been described. How-ever, a stent might be prepared by other methods such as extending and forming a stent extirely of soft, flexible material and thereafter stiffening the proximal hook by leaching plasticizer therefrom or coating it with more material and increasing its thickness. Likewise, use of connectors to joining the proximal hook portion to the main body of the stent is less desirable since the connectors may increase the outside diameter of the stent or reduce the size of the lumen or fail.
It will be readily apparent to those skilled in the art that a number of modifications and changes can be made with-out departing from the spirit of the invention. Therefore, it is to be understood thalt the scope of the invention is not be be limited by the foregoin,g description, but only by the claims. ---'
Claims (13)
1. An ureteral stent comprising:
a soft flexible main body; and a nonreinforced hook portion connected to said body for placement in a kidney of a patient to reduce the likelihood of expulsion or migration of said stent, said nonreinforced hook portion being stiffer that said body and formed from a material having a memory at body temperature sufficient to resume a hook shape when said hook portion is straightened with a straightening force, placed in said kidney of said patient, and said straightening force is removed.
a soft flexible main body; and a nonreinforced hook portion connected to said body for placement in a kidney of a patient to reduce the likelihood of expulsion or migration of said stent, said nonreinforced hook portion being stiffer that said body and formed from a material having a memory at body temperature sufficient to resume a hook shape when said hook portion is straightened with a straightening force, placed in said kidney of said patient, and said straightening force is removed.
2. An ureteral stent of claim 1 in which the material of the hook is a homogenous material having a durometer of about 95 Shore 'A'.
3. An ureteral stent of claim 1 in which the material of the hook portion is a homogenous, essentially linear, segmented aliphatic polyurethane elastomer composed of three repeating units, a diol, a diisocyanate and a macroglycol.
4. An ureteral stent of claim 1 in which the main body of the stent is a soft, flexible material having a durometer of about 50 to about 85 Shore 'A'.
5. An ureteral stent of claim 1 in which the main body of the stent is made of a material which is an essentially linear, segmented aliphatic polyurethane elastomer compound of three repeating units, a diol, a diisocyanate and a macroglycol.
6. An ureteral stent comprising a hook at one end portion of said stent for placement in a kidney of a patient and a hook of another end portion of said stent for placement in a bladder of said patient, wherein said hook at said one end portion is formed from a stiffer material than said hook at said another end portion.
7. An ureteral stent of claim 6 in which the stiffer material is a homogenous material which has a durometer of about 95 Shore 'A'.
8. An ureteral stent of claim 6 in which the stiffer material consists essentially of a homogenous essentially linear, segmented aliphatic polyurethane elastomer composed of three repeating units, a diol, a diisocyanate and a macroglycol.
9. An ureteral stent of claim 6 in which the stiffer material is a homogenous polymer which possesses good memory so that it quickly resumes a molded shape at body temperature.
10. An ureteral stent comprising:
a soft flexible main body having an elongated member and a bladder hook adapted for placement in a bladder of a patient; and a kidney hook connected to said elongated member of said body and adapted for placement in a kidney of said patient, said kidney hook being stiffer that said bladder hook and formed from a homogenous material having a durometer of about 95 Shore 'A' and a memory sufficient to resume a hook shape at body temperature when a hook straightening force is removed.
a soft flexible main body having an elongated member and a bladder hook adapted for placement in a bladder of a patient; and a kidney hook connected to said elongated member of said body and adapted for placement in a kidney of said patient, said kidney hook being stiffer that said bladder hook and formed from a homogenous material having a durometer of about 95 Shore 'A' and a memory sufficient to resume a hook shape at body temperature when a hook straightening force is removed.
11. A ureteral stent of claim 10 in which the material of the soft, flexible main body of the stent is a polyurethane having a durometer of about 50 to about 80 Shore 'A'.
12. An ureteral stent of claim 10 in which the material of the relatively stiff hook is a polyurethane having a durometer of about 95 Shore 'A'.
13. In a ureteral stent comprising an elongated member having a soft, flexible main body with a first hook at one end for placement in the bladder of a patient and a second hook at the other end for placement in the patient's kidney, the improvement which comprises forming said stent of a homogeneous, essentially linear, segmented aliphatic polyurethane elastomer composed of three repeating units, a diol, a diisocyanate and a macroglycol, the main body and first hook of said stent having a durometer of about 50 to about 80 Shore 'A' and the second hook having a durometer of about 95 Shore 'A' and a good memory that enables it to quickly resume its hook shape at body temperature when a hook straightening force has been removed.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US07/214,180 US4874360A (en) | 1988-07-01 | 1988-07-01 | Ureteral stent system |
| US214,180 | 1988-07-01 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1338031C true CA1338031C (en) | 1996-02-06 |
Family
ID=22798082
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000604092A Expired - Fee Related CA1338031C (en) | 1988-07-01 | 1989-06-27 | Ureteral stent system |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US4874360A (en) |
| JP (1) | JP2933948B2 (en) |
| CA (1) | CA1338031C (en) |
| DE (1) | DE3921634C2 (en) |
| FR (1) | FR2633521B1 (en) |
Families Citing this family (83)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2561853B2 (en) * | 1988-01-28 | 1996-12-11 | 株式会社ジェイ・エム・エス | Shaped memory molded article and method of using the same |
| US5085629A (en) * | 1988-10-06 | 1992-02-04 | Medical Engineering Corporation | Biodegradable stent |
| DE3900738A1 (en) * | 1989-01-12 | 1990-07-19 | Sachse Hans E | Ureteral stent with clamping mandrin |
| US5190528A (en) * | 1990-10-19 | 1993-03-02 | Boston University | Percutaneous transseptal left atrial cannulation system |
| US5176625A (en) * | 1990-10-25 | 1993-01-05 | Brisson A Glen | Stent for ureter |
| US5295954A (en) * | 1990-11-20 | 1994-03-22 | Sachse Hans Ernst | Arrangement consisting of ureter tube, (stent) mandrin and auxiliary tube |
| US5330432A (en) * | 1991-12-06 | 1994-07-19 | Inbae Yoon | Retractable safety penetrating instrument |
| US5141502A (en) * | 1991-08-28 | 1992-08-25 | Macaluso Jr Joseph N | Ureteral stent |
| US5269802A (en) * | 1991-09-10 | 1993-12-14 | Garber Bruce B | Prostatic stent |
| US5391155A (en) * | 1991-09-13 | 1995-02-21 | Sachse; Hans | Arrangement comprising a ureter tube, an auxiliary tube as well as a mandrin |
| DE4141155C2 (en) * | 1991-09-13 | 1994-03-17 | Sachse Hans E | Arrangement with a ureteral splint, an auxiliary splint and a stylet |
| US5409468A (en) * | 1991-09-13 | 1995-04-25 | Sachse; Hans | Arrangement comprising a ureter tube, an auxiliary tube as well as a mandrin |
| US5282784A (en) * | 1991-10-09 | 1994-02-01 | Mentor Corporation | Injection stent system |
| US5256146A (en) * | 1991-10-11 | 1993-10-26 | W. D. Ensminger | Vascular catheterization system with catheter anchoring feature |
| US5376084A (en) * | 1991-10-17 | 1994-12-27 | Imagyn Medical, Inc. | Catheter with internal mandrel and method |
| US5281236A (en) * | 1992-06-23 | 1994-01-25 | Boston Scientific Corporation | Method and device for intracorporeal knot tying |
| US5496331A (en) * | 1993-07-28 | 1996-03-05 | Terumo Kabushiki Kaisha | Knot-forming instrument and method of forming knots |
| DE4440346A1 (en) * | 1994-11-13 | 1996-05-15 | Daum Gmbh | Puncture instrument |
| US5713853A (en) * | 1995-06-07 | 1998-02-03 | Interventional Innovations Corporation | Methods for treating thrombosis |
| US6280413B1 (en) | 1995-06-07 | 2001-08-28 | Medtronic Ave, Inc. | Thrombolytic filtration and drug delivery catheter with a self-expanding portion |
| US6991614B2 (en) * | 1995-11-07 | 2006-01-31 | Boston Scientific Scimed, Inc. | Ureteral stent for improved patient comfort |
| US6676623B2 (en) * | 2001-05-04 | 2004-01-13 | Scimed Life Systems, Inc. | Drainage devices and methods |
| US6849069B1 (en) * | 1995-11-07 | 2005-02-01 | Boston Scientitfic Corporation | Medical device with tail(s) for assisting flow of urine |
| US5830224A (en) * | 1996-03-15 | 1998-11-03 | Beth Israel Deaconess Medical Center | Catheter apparatus and methodology for generating a fistula on-demand between closely associated blood vessels at a pre-chosen anatomic site in-vivo |
| US5904670A (en) * | 1996-04-03 | 1999-05-18 | Xrt Corp. | Catheters and methods for guiding drugs and other agents to an intended site by deployable grooves |
| US5647843A (en) * | 1996-05-24 | 1997-07-15 | Vance Products Incorporated | Anti-reflux ureteral stent |
| US6060534A (en) | 1996-07-11 | 2000-05-09 | Scimed Life Systems, Inc. | Medical devices comprising ionically and non-ionically crosslinked polymer hydrogels having improved mechanical properties |
| JP3527378B2 (en) * | 1997-01-31 | 2004-05-17 | テルモ株式会社 | Contrast catheter |
| US5795319A (en) * | 1997-03-07 | 1998-08-18 | Circon Corporation | Easily removable ureteral stent |
| US6248100B1 (en) | 1997-08-14 | 2001-06-19 | Scimed Life Systems, Inc. | Drainage catheter delivery system |
| US5921952A (en) * | 1997-08-14 | 1999-07-13 | Boston Scientific Corporation | Drainage catheter delivery system |
| JP4612186B2 (en) | 1998-02-24 | 2011-01-12 | ナビリスト メディカル， インコーポレイテッド | High flow dialysis catheter and related methods |
| US6332892B1 (en) | 1999-03-02 | 2001-12-25 | Scimed Life Systems, Inc. | Medical device with one or more helical coils |
| US6709465B2 (en) | 1999-03-18 | 2004-03-23 | Fossa Medical, Inc. | Radially expanding ureteral device |
| US7214229B2 (en) | 1999-03-18 | 2007-05-08 | Fossa Medical, Inc. | Radially expanding stents |
| US6214037B1 (en) | 1999-03-18 | 2001-04-10 | Fossa Industries, Llc | Radially expanding stent |
| US6238383B1 (en) * | 1999-07-20 | 2001-05-29 | Medical Device Solutions | Apparatus and method to facilitate intermittent self-catheterization by a user |
| US6585759B1 (en) | 1999-12-16 | 2003-07-01 | Israel Aircraft Industries Ltd. | Method and apparatus for manufacturing medical support devices |
| US7278195B2 (en) * | 1999-12-16 | 2007-10-09 | Israel Aircraft Industries Ltd. | Method for producing a coated medical support device |
| US6569150B2 (en) | 2000-04-11 | 2003-05-27 | Scimed Life Systems, Inc. | Reinforced retention structures |
| US6764519B2 (en) | 2000-05-26 | 2004-07-20 | Scimed Life Systems, Inc. | Ureteral stent |
| US6719804B2 (en) | 2001-04-02 | 2004-04-13 | Scimed Life Systems, Inc. | Medical stent and related methods |
| US6494855B2 (en) | 2001-05-16 | 2002-12-17 | Scimed Life Systems, Inc. | Draining bodily fluid |
| US6921378B2 (en) * | 2001-10-09 | 2005-07-26 | Boston Scientific Scimed, Inc. | Anti-reflux drainage devices and methods |
| US6620202B2 (en) * | 2001-10-16 | 2003-09-16 | Scimed Life Systems, Inc. | Medical stent with variable coil and related methods |
| US7041139B2 (en) | 2001-12-11 | 2006-05-09 | Boston Scientific Scimed, Inc. | Ureteral stents and related methods |
| US8506647B2 (en) | 2002-02-14 | 2013-08-13 | Boston Scientific Scimed, Inc. | System for maintaining body canal patency |
| US6913625B2 (en) * | 2002-03-07 | 2005-07-05 | Scimed Life Systems, Inc. | Ureteral stent |
| US8328877B2 (en) | 2002-03-19 | 2012-12-11 | Boston Scientific Scimed, Inc. | Stent retention element and related methods |
| US6949125B2 (en) * | 2002-04-16 | 2005-09-27 | Boston Scientific Scimed, Inc. | Ureteral stent with end-effector and related methods |
| US7976936B2 (en) * | 2002-10-11 | 2011-07-12 | University Of Connecticut | Endoprostheses |
| US7264858B2 (en) * | 2002-10-29 | 2007-09-04 | Lubrizol Advanced Materials, Inc. | Multilayered articles having biocompatibility and biostability characteristics |
| US20040087886A1 (en) * | 2002-10-30 | 2004-05-06 | Scimed Life Systems, Inc. | Linearly expandable ureteral stent |
| US20040088835A1 (en) * | 2002-11-08 | 2004-05-13 | Tachauer Ernesto S. | Active fasteners |
| US7044981B2 (en) * | 2003-01-22 | 2006-05-16 | Boston Scientific Scimed, Inc. | Ureteral stent configured for improved patient comfort and aftercare |
| US7182745B2 (en) * | 2003-03-25 | 2007-02-27 | Boston Scientific Scimed, Inc. | Retaining stent |
| US6929664B2 (en) * | 2003-12-05 | 2005-08-16 | Fossa Medical, Inc. | Open lumen stents |
| US7507218B2 (en) * | 2004-04-26 | 2009-03-24 | Gyrus Acmi, Inc. | Stent with flexible elements |
| US20050240141A1 (en) * | 2004-04-26 | 2005-10-27 | Peter Aliski | Stent kidney curl improvements |
| US7470247B2 (en) * | 2004-04-26 | 2008-12-30 | Gyrus Acmi, Inc. | Ureteral stent |
| US20050240278A1 (en) * | 2004-04-26 | 2005-10-27 | Peter Aliski | Stent improvements |
| US7396366B2 (en) * | 2005-05-11 | 2008-07-08 | Boston Scientific Scimed, Inc. | Ureteral stent with conforming retention structure |
| US8828091B2 (en) * | 2006-03-23 | 2014-09-09 | Boston Scientific Scimed, Inc. | Movable stent reinforcement |
| US9585989B2 (en) * | 2006-09-19 | 2017-03-07 | Boston Scientific Scimed, Inc. | Ureteral stent having variable hardness |
| CA2665868C (en) * | 2006-10-16 | 2013-08-06 | Wilson-Cook Medical Inc. | Nonexpandable stent |
| JP4906526B2 (en) * | 2007-01-29 | 2012-03-28 | セントラル自動車株式会社 | Conveyor device |
| JP5630014B2 (en) | 2009-01-30 | 2014-11-26 | ソニー株式会社 | Manufacturing method of liquid crystal display device |
| US8753303B2 (en) | 2009-09-25 | 2014-06-17 | Boston Scientific Scimed, Inc. | Delivery system having stent locking structure |
| US9339631B2 (en) | 2009-09-25 | 2016-05-17 | Boston Scientific Scimed, Inc. | Locking mechanism for a medical device |
| US9408733B2 (en) | 2009-12-30 | 2016-08-09 | Michael Devon Amos | Rotatable connection between a tubular member and an elongate wire of a catheter |
| CA2817831C (en) | 2010-11-19 | 2021-02-23 | Boston Scientific Scimed, Inc. | Rapid exchange stent delivery system |
| WO2013003450A1 (en) | 2011-06-27 | 2013-01-03 | Boston Scientific Scimed, Inc. | Stent delivery systems and methods for making and using stent delivery systems |
| US9750621B2 (en) * | 2012-06-08 | 2017-09-05 | University Hospitals Cleveland Medical Center | Ureteral stent for placement in a kidney and bladder |
| US9254203B2 (en) | 2012-08-20 | 2016-02-09 | Boston Scientific Scimed, Inc. | Delivery device |
| US10406276B2 (en) | 2013-03-14 | 2019-09-10 | The General Hospital Corporation | System and method for guided removal from an in vivo subject |
| US20160030070A1 (en) | 2013-03-14 | 2016-02-04 | The General Hospital Corporation | System and method for guided removal from an in vivo subject |
| US10398541B2 (en) | 2013-03-14 | 2019-09-03 | The General Hospital Corporation | System and method for use of flexible anti-reflux ureteral stent |
| US20140358245A1 (en) * | 2013-05-30 | 2014-12-04 | Boston Scientific Scimed, Inc. | Segmental ureteral stent |
| JP5408682B1 (en) * | 2013-06-28 | 2014-02-05 | ガデリウス・メディカル株式会社 | Stent kit |
| AU2015243533A1 (en) * | 2014-04-10 | 2016-10-27 | C.R. Bard, Inc. | Ureteral stents |
| BE1022953B1 (en) * | 2015-06-04 | 2016-10-21 | Wuhan General Hospital Of Guangzhou Military | Magnetic double-J hose and hose puller |
| WO2017192145A1 (en) | 2016-05-06 | 2017-11-09 | University Hospitals Health Systems, Inc. | Ureteral stent |
| US20210121188A1 (en) | 2018-02-02 | 2021-04-29 | Calyxo, Inc. | Devices and methods for minimally invasive kidney stone removal by combined aspiration and irrigation |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4169464A (en) * | 1977-12-16 | 1979-10-02 | Cordis Corporation | Catheter for selective catheterization of aortic branches |
| US4212304A (en) * | 1978-04-07 | 1980-07-15 | Medical Engineering Corp. | Uretheral catheter stent |
| US4307723A (en) * | 1978-04-07 | 1981-12-29 | Medical Engineering Corporation | Externally grooved ureteral stent |
| AU560959B2 (en) * | 1981-10-30 | 1987-04-30 | Thermo Electron Corporation | Polyurethane for medical purpose |
| US4447590A (en) * | 1981-10-30 | 1984-05-08 | Thermo Electron Corporation | Extrudable polyurethane for prosthetic devices prepared from a diisocyanate, a polytetramethylene ether polyol and 1,4 butane diol |
| US4523005A (en) * | 1981-10-30 | 1985-06-11 | Thermedics, Inc. | Extrudable polyurethane for prosthetic devices prepared from a diisocyanate, a polytetramethylene ether polyol, and 1,4-butane diol |
| US4531933A (en) * | 1982-12-07 | 1985-07-30 | C. R. Bard, Inc. | Helical ureteral stent |
| US4610657A (en) * | 1984-01-03 | 1986-09-09 | Medical Engineering Corporation | Ureteral stent |
| US4671795A (en) * | 1984-11-19 | 1987-06-09 | Mulchin William L | Permanent/retrievable ureteral catheter |
| US4713049A (en) * | 1986-08-05 | 1987-12-15 | Medical Engineering Corporation | Ureteral stent kit |
| DE8801101U1 (en) * | 1988-01-30 | 1988-03-17 | B. Braun Melsungen Ag, 3508 Melsungen, De |
-
1988
- 1988-07-01 US US07/214,180 patent/US4874360A/en not_active Expired - Lifetime
-
1989
- 1989-06-27 CA CA000604092A patent/CA1338031C/en not_active Expired - Fee Related
- 1989-06-30 JP JP1167141A patent/JP2933948B2/en not_active Expired - Fee Related
- 1989-06-30 DE DE3921634A patent/DE3921634C2/en not_active Expired - Fee Related
- 1989-06-30 FR FR8908776A patent/FR2633521B1/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0252646A (en) | 1990-02-22 |
| DE3921634A1 (en) | 1990-01-04 |
| US4874360A (en) | 1989-10-17 |
| FR2633521B1 (en) | 1995-04-21 |
| JP2933948B2 (en) | 1999-08-16 |
| FR2633521A1 (en) | 1990-01-05 |
| DE3921634C2 (en) | 2002-10-17 |
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| Date | Code | Title | Description |
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| MKLA | Lapsed |