WO2018061021A1

WO2018061021A1 - A ureteral stent

Info

Publication number: WO2018061021A1
Application number: PCT/IN2017/050205
Authority: WO
Inventors: Divakar DALELA
Original assignee: Dalela Divakar
Priority date: 2016-09-29
Filing date: 2017-05-29
Publication date: 2018-04-05

Abstract

The invention provides a ureteral stent including an axis defining flexible tube. The flexible tube is configured to form a proximal end and a distal end. The proximal end is capable of forming a retractable loop away from the axis. The distal end is configured to form two distinct regions. The first region has a partially rigid structure situated proximal to the distal end and the second region is capable of forming a retractable loop formed out of the first region.

Description

A U R E T E RAL S T E NT

FIE L D OF INVE NTION

The invention generally relates to the field of medical devices and particularly to a ureteral stent.

BAC KG R OU ND

Urinary obstruction or blockage in flow of urine in kidneys is a common disease, which is mainly caused by stones, strictures and tumors. To temporarily de-block the obstructed kidney, urologists often pass a stent inside the involved ureter to create an internal bypass mechanism, whereby the urine flows from the kidney collecting system down to the urinary bladder. There are stents known in the art that are used for internal drainage of the obstructed kidney.

FIG .1 shows, a stent employed to de-block the obstructed kidney, according to a device known in the art. The stent is called DJ stent or J J stent. The J J stent has two J like coils at both ends to prevent its up migration and down migration. A significant disadvantage of J J stent is that, a number of patients experience dysuria when the J J stent is placed inside the kidney. Another disadvantage of the J J stent is irritation of a trigone area of the urinary bladder, which in turn causes urgency to pass urine and increased urinary frequency. The irritation of the trigone is caused due to dangling of lower end of the stent in the urinary bladder, which keeps coming closer to bladder neck. FIG .1 shows the impingement of the J J stent on the urinary bladder, according to an embodiment known to exist (prior art). A lower coil 101 of the J J stent as shown in FIG .1 (a) moves down with every inspiration. With every inspiration, the lower coil 101 is pushed on to the trigone 102 and the outlet 103 of urinary bladder 104 as shown in FIG .1 (b). Thus, there exists a need for a stent that minimizes the problems of dysuria, urgency and increased urinary frequency. B RIE F D E S C RIPTIO N O F DRAWINGS

S o that the manner in which the recited features of the invention can be understood in detail, some of the embodiments are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.

FIG .1 shows the impingement of the J J stent on the urinary bladder, according to an embodiment known to exist (prior art). FIG .2 shows a ureteral stent, according to an embodiment of the invention.

FIG .3 shows a distal end of the ureteral stent in the urinary bladder of a patient, according to an embodiment of the invention.

FIG .4 shows an x-ray image of the ureteral stent in the patient, according to an embodiment of the invention. FIG .5(a) shows a first stage in the positioning of the ureteral stent in the ureter of the patient, according to an example of the invention.

FIG .5(b) shows a second stage in the positioning of the ureteral stent in the ureter of the patient, according to an embodiment of the invention.

FIG .5(c) shows a third stage in the positioning of the ureteral stent in the ureter of the patient, according to an embodiment of the invention.

FIG .5(d) shows a fourth stage in the positioning of the ureteral stent in the ureter of the patient, according to an embodiment of the invention.

FIG .5(e) shows a fifth stage in the positioning of the ureteral stent in the ureter of the patient, according to an embodiment of the invention.

FIG .5(f) shows a final stage in the positioning of the ureteral stent in the ureter of the patient, according to an embodiment of the invention.

S U MMARY O F TH E INVE NTION

One aspect of the invention provides a ureteral stent including an axis defining flexible tube. The flexible tube is configured to form a proximal end and a distal end. The proximal end is capable of forming a retractable loop away from the axis. The distal end is configured to form two distinct regions. The first region has a partially rigid structure situated proximal to the distal end and the second region is capable of forming a retractable loop formed out of the first region. DETAIL E D DE S C RIPTION O F TH E INVE NTIO N

Various embodiments of the invention provide a ureteral stent including an axis defining flexible tube. The flexible tube is configured to form a proximal end and a distal end. The proximal end is capable of forming a retractable loop away from the axis. The distal end is configured to form two distinct regions. The first region has a partially rigid structure situated proximal to the distal end and the second region is capable of forming a retractable loop formed out of the first region.

FIG .2 shows a ureteral stent 1 , according to an embodiment of the invention. The ureteral stent 1 includes an axis defining flexible tube 2. The flexible tube 2 is configured to form a proximal end 3 and a distal end 5. The proximal end 3 is capable of forming a retractable loop 3a away from the axis. The distal end 5 is configured to form two distinct regions. The first region 5a has a partially rigid structure situated proximal to the distal end 5 and the second region 5b is capable of forming a retractable loop formed out of the first region 5a. The partially rigid structure extends away from the axis. The extended partially rigid structure subtends an angle in the range of about 35° to about 45°. The angle subtended is with respect to the axis of the tube 2. The first region 5a is capable of retaining the partially rigid structure subsequent to extension. The tube 2 described herein has a hollow cross-section of uniform diameter throughout the length of the tube 2. The hollow cross-section is capable of receiving a guiding wire for insertion and/or removal of the ureteral stent 1. The insertion and/or removal of the ureteral stent 1 is from a patient. The proximal end 3 is positioned within a kidney of the patient. The distal end 5 is positioned within a urinary bladder of the patient. The distal end 5 is preferably positioned away from a trigone area in the urinary bladder of the patient. The configuration of the distal end 5 retains the distal end 5 away from the trigone area of the urinary bladder. The distal end 5 retractably extends to conform to the axis of the tube 1 during insertion and/or removal of the ureteral stent.

FIG .3 shows the distal end 5 of the ureteral stent 1 in the urinary bladder 7 of the patient, according to an embodiment of the invention. The distal end 5 is configured to form two distinct regions. The first region 5a has a partially rigid structure situated proximal to the distal end 5 and the second region 5b is capable of forming a retractable loop formed out of the first region 5a. The configuration of the distal end 5 retains the distal end 5 away from the trigone area 7a and outlet 7b of the urinary bladder 7. The position of the distal end 5 slightly varies depending on a plurality of parameters which include but are not limited to volume of urine in the bladder and the posture of patient.

FIG .4 shows an x-ray image of the ureteral stent 1 in a patient, according to an embodiment of the invention. The x-ray shows the proximal end of the ureteral stent within the ureter of the patient and the distal end of the ureteral stent within the urinary bladder of the patient. The configuration of the distal end retains the distal end away from the trigone area of the urinary bladder. FIG .5(a) - 5(f) generally shows positioning of the ureteral stent 1 in the ureter 9 of the patient, according to an example of the invention. The positioning of the ureteral stent 1 in the ureter 9 is performed using a plurality of techniques. The plurality of techniques described herein includes but are not limited to cystoscopy, nephroscopy and/or fluoroscopy.

FIG .5(a) shows a first stage in the positioning of the ureteral stent 1 in the ureter 9 of the patient, according to an embodiment of the invention. The first stage includes placement of the guiding wire 1 1 in the ureter 9 under cystoscopic vision. The guiding wire 1 1 is passed inside the ureter 9 using a cystoscope 13, bypassing the site of obstruction in ureter 9. In an example of the invention, the guiding wire 1 1 described herein is a flexible hydrogel coated wire.

FIG .5(b) shows a second stage in the positioning of the ureteral stent in the ureter of the patient, according to an embodiment of the invention. S ubsequent to the placement of the guiding wire 1 1 in the ureter 9, the proximal end 3 of the ureteral stent 1 is gradually passed over the guiding wire 1 1 . The second stage shows the sliding of the proximal end 3 of the ureteral stent 1 over the guiding wire 1 1.

FIG .5(c) shows a third stage in the positioning of the ureteral stent in the ureter of the patient, according to an embodiment of the invention. The third stage is the advancement of the proximal end 3 of the ureteral stent 1 over the guiding wire 1 1 in the ureter 9. The advancement of the proximal end 3 of the ureteral stent 1 over the guiding wire 1 1 is monitored under fluoroscopic vision of Image Intensifier using X-rays.

FIG .5(d) shows a fourth stage in the positioning of the ureteral stent in the ureter of the patient, according to an embodiment of the invention. The guiding wire 1 1 is withdrawn when the proximal end of the ureteral stent 1 reaches the broadened top part of the ureter 9. Upon withdrawal of the guiding wire 1 1 in the fluoroscopic vision of Image Intensifier, the proximal end 3 of the ureteral stent is coiled in the ureter 9.

FIG .5(e) shows a fifth stage in the positioning of the ureteral stent in the ureter of the patient, according to an embodiment of the invention. As the guiding wire 1 1 is withdrawn from the distal end 5 of the ureteral stent 1 , in the combined cystoscopic and fluoroscopic vision of Image Intensifier, the first region 5a of the distal end 5 is pushed inside urinary bladder 7.

FIG .5(f) shows a final stage in the positioning of the ureteral stent 1 in the ureter 9 of the patient, according to an embodiment of the invention. The distal end 5 of the ureteral stent 1 is coiled and shifted towards the dome of urinary bladder 7. The distal end 5 is retained away from the trigone area 7a of the urinary bladder. S ubsequent to the placement of the ureteral stent 1 in the ureter 9, the cystoscope 13 is withdrawn.

Thus the invention provides a ureteral stent that facilitates the flow of urine from kidney to bladder, by-passing the function of ureter to some extent. The ureteral stent reduces the impact of lower end of the stent on the trigone, thereby minimizing the problems of dysuria, urgency and increased urinary frequency. The foregoing description of the invention has been set merely to illustrate the invention and is not intended to be limiting. S ince modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to person skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.

Claims

C laim:

1. A ureteral stent comprising of an axis defining flexible tube configured to form

a proximal end, wherein the proximal end is capable of forming a retractable loop away from the axis; and a distal end configured to form two distinct regions, the first region having a partially rigid structure situated proximal to the distal end and the second region capable of forming a retractable loop formed out of the first region;

2. The ureteral stent of claim 1 , wherein the partially rigid structure extends away from the axis.

3. The ureteral stent of claim 1 , wherein the extended partially rigid structure subtends an angle in the range of about 35° to a bout 45°.

4. The ureteral stent of claim 1 , wherein the angle subtended is with respect to the axis of the tube.

5. The ureteral stent of claim 1 , wherein the first region is capable of retaining the partially rigid structure subsequent to extension.

6. The ureteral stent of claim 1 , wherein the tube has a hollow cross-section of uniform diameter throughout the length of the tube.

7. The ureteral stent of claim 1 , wherein the hollow cross- section is capable of receiving a guiding wire for insertion and/or removal of the ureteral stent.

8. The ureteral stent of claim 1 , wherein the insertion and/or removal of the ureteral stent is from a patient.

9. The ureteral stent of claim 1 , wherein the proximal end is positioned within an ureter of the patient.

10. The ureteral stent of claim 1 , wherein the distal end is positioned within a urinary bladder of the patient.

1 1. The ureteral stent of claim 1 , wherein the distal end is preferably positioned away from a trigone area in the urinary bladder of the patient.

12. The ureteral stent of claim 1 , wherein the configuration of the distal end retains the distal end away from the trigone area of the urinary bladder.

13. The ureteral stent of claim 1 , wherein the distal end retractably extends to conform to the axis of the tube during insertion and/or removal of the ureteral stent.