Claims:CLAIMS:
We claim:
1. A device for ureteral stent delivery comprising of:
a ureteral stent 100 and
an introducer system 200 wherein the said introducer system 200 comprises of a metal stylet 201, transparent sheath 202, introducer sheath 203 and hub 204.

2. The device for ureteral stent delivery as claimed in claim 1, wherein metal stylet 201 is covered by a transparent introducer sheath 202 and flexible cannula with hub which allows stent loading on the assembly and when removed provides a lumen for accessing over the guide wire insertion.

3. The device for ureteral stent delivery as claimed in claim 1, wherein the introducer sheath 203 and a flexible cannula are provided with Luer locking hubs 204 for contrast media injection and the over length covers the stent length that avoids the leakage of contrast media in between.

4. The device for ureteral stent delivery as claimed in claim 1, wherein the introducer is transparent to provide hub provision for injecting contrast media; the length of the introducer sheath is configured to allow contrast media injection into renal system to check the accuracy of deployment of stent; and to maintain patency in both the lumens.

5. A method of ureteral stent delivery comprises the steps of:
loading the ureteral stent over the diagnostic introducer system and remove the stylet 301;
passing a guide wire through the scope and inserting the assembly through the scope over the guide wire and then removing the guide wire 302;
removing the said guide wire and then injecting the contrast media to perform retrograde pyelogram 303;
holding the introducer sheath and remove the transparent sheath which is visually observed for stent deployment 304.
observing the curling of loop at the proximal end and pull the transparent sheath completely 305.

6. The method of ureteral stent delivery as claimed in claim 5, wherein the stent is deployed fully and injecting the contrast media through the introducer sheath 202 is achieved and after confirmation of stent placement then remove the introducer sheath 202.

7. The method of ureteral stent delivery as claimed in claim 1, wherein the introducer system is an assembly for delivering contrast media, guide wire and deploying ureteral stent in an individual’s ureter in a single step.
, Description:FIELD OF INVENTION
The present invention relates to the field of ureteral stenting procedures. More particularly, the invention relates a trans-nephrostomy drainage system characterized by a ureteral stent and diagnostic introducer system deployment and repositioning of a drainage catheter within the body cavity.
BACKGROUND OF THE INVENTION
A ureteral stent is a thin, flexible tube threaded into the ureter. A ureteral stent is mostly used when there is a blockage in the ureter and allows urine to drain around the blockage. Kidney stones and ureteral obstructions are main reasons for receiving ureteral stents. In instances where the ureteral stent cannot be placed nephrostomy is the solution.
Ureteral stents are widely accepted and are the most feasible prostheses for ureteral obstructions and helps in drainage between the kidneys and the bladder.
Conventional method in the ureteral stenting is first to pass the scope then the guide wire through the scope. This is followed by passing the ureteral catheter over the guide wire. Then the guide wire is removed. After this retrograde pyelogram is performed by injecting the contrast media and then again passing the guide wire. Now the ureteral catheter is removed and the stent is passed over the guide wire finally the guide wire is removed.
Existing available devices consist of external or internal ureteral catheters. Externalized ureteral catheters drain the upper urinary tract and pass through the bladder, exiting the urethra and draining into an external collecting device. They allow drainage through ports and a central lumen and can be irrigated as needed to drain tenacious and obstructing material. By draining externally, the output from the involved renal unit can be carefully monitored. Contrast media can be injected as needed to evaluate the upper tract. These methods and systems are not self-contained and must be secured to an indwelling urethral catheter or they will migrate and be extruded by ureteral peristalsis. Hence are not suitable for long-term outpatient care.
To solve the problems of the existing external catheters, internalized ureteral catheters were developed. The most commonly used type is a plastic catheter with a curl at both the proximal and distal ends; i.e., Double J catheter. The curls are straightened over a central stiffening wire in order to pass the stent, but are reformed when the stiffening wire is removed. The proximal curl prevents distal migration and thereby keeps the device in the renal pelvis. The distal curl is positioned in the bladder to allow completely internalized drainage. No urethral catheter is needed to secure this type of stent, making it ideal for outpatient management.
There are several prior-arts that are related to ureteral stent. The patent US4957479A discloses an indwelling ureteral stent positioning apparatus for allowing single intrusion placement of a stent in the ureter of a patient. The apparatus is pre-assembled and includes a wire guide with floppy tip. The stent is positioned about the wire guide adjacent to the floppy tip of the wire guide, and is adjustably situated on the wire guide to expose a pre-determined length of the floppy tip for insertion into the patient. The stent is a dual open-ended tubular stent having a resilient retentive curved circular or pigtail shape at each end for retention in the kidney and bladder. A positioner is conveyed on the wire stent until the end of the positioned abuts the anatomically distal end of the stent. A pin-vise clamp abuts the external end of the positioner and releasably engages the wire guide to stabilize the apparatus during insertion. When used to position the stent within the ureter, the apparatus is conveyed along the ureter until the floppy tip is within the renal collecting system. The positioner is advanced along the wire guide to push the anatomically proximal end of the stent over and beyond the floppy tip so that the retentive coil forms within the kidney. The pin-vise clamp is released to allow the wire guide to be withdrawn until it passes the anatomically distal end of the stent, wherein the retentive coil shape is formed within the bladder. With the stent fully indwelling, the positioner and wire guide are removed from the patient.
Another patent US6264624B1 discloses a drainage catheter delivery system for positioning a drainage catheter or stent within a body cavity, such as a ureter. The delivery system includes a guide catheter, a push catheter, a drainage catheter (or stent) and a retention device. The guide catheter includes an outer diameter sized to slidably receive the push catheter and the drainage catheter. In this regard, the push catheter is placed over the guide catheter proximal to the drainage catheter. The retention device selectively connects the push catheter to the drainage catheter. During use, the delivery system is pre-assembled as described above. The assembled delivery system is directed within a body cavity such that a distal end of the guide catheter is in close proximity to the desired drainage catheter position. The push catheter is axially slid along the guide catheter to move the drainage catheter away from the proximal end of the guide catheter. Conversely, the drainage catheter is retracted, or moved toward the proximal end of the guide catheter by retraction of the push catheter. Retraction of the push catheter retracts the drainage catheter via the retention device. Once properly positioned, the drainage catheter is released from the retention device by retracting the guide catheter from the drainage catheter.
Similarly, the patent US5346467A discloses a combination of ureteral stent-ureteral catheter comprising an elongated flexible tubular member which has proximal and distal ends in the form of curls when present in its internalized stent form and which further comprises an elongated tubular rigid extension attached to the distal end of the stent which allows the combination to function as an externalized ureteral catheter. On extracting the rigid extension from the stent while the device is in place, the distal end of the stent reforms itself into a preformed curl and thereafter functions as a Double J internalized catheter or stent.
The problem with the current systems and methods is the frequency of exchanging devices which not only increases the procedural time but also increases the risk of infection to the patient.
The existing system requires extra catheter for contrast media injection and there is a need for exchanging catheter/guidewire during the procedure. Safety wires are needed in place to secure access. Conventional lab testing procedural time is 5 mins 14 sec and more procedural time has high chance of infection.
Mishandling of devices during exchange may lead to guide wire slippage for which the doctors are currently using an additional safety wire in position.
To overcome the problems faced in the existing systems, the present invention implements a system that focuses on the decrease of operational time by reducing the number of steps involved in stenting procedure and also a design that minimizes the need of exchange wire.
SUMMARY OF THE INVENTION
The following summary is provided to facilitate a clear understanding of the new features in the disclosed embodiment and it is not intended to be a full, detailed description. A detailed description of all the aspects of the disclosed invention can be understood by reviewing the full specification, the drawing and the claims and the abstract, as a whole.
The main objective of our system is to provide a trans-nephrostomy drainage delivery device and a method for delivery.
In accordance with the present invention the device comprises of two components that enable the drainage, i.e, ureteral stent and introducer system.
In accordance with this present invention an introducer assembly for delivering contrast media or guide wire and deploying ureteral stent into a patient’s ureter is achieved in a single step.
In another aspect of the present invention the said metal stylet is covered by transparent introducer sheath.
In another aspect of the present invention the said metal stylet allows stent loading onto the assembly and when removed provides a lumen for accessing over the guide wire insertion.
In accordance with this present invention the said introducer assembly allows injection of contrast media in specific site and stent deployment.
In another aspect of the present invention the said introducer kit confirmation of stent placement with minimal or no requirement of guide wire exchange.
In another aspect of the present invention an introducer sheath and a flexible cannula are provided with Luer locking hubs for contrast media injection.
Yet another objective of the present invention is to provide a device and method comprising ureteral stent and introducer which enables to decrease the operational time by reducing the number of steps involved in stenting procedure and also the novel design minimizes the need of exchange wire.
BRIEF DESCRIPTION OF THE DRAWINGS
The manner in which the proposed system works is given a more particular description below, briefly summarized above, may be had by reference to the components, some of which is illustrated in the appended drawing It is to be noted; however, that the appended drawing illustrates only typical embodiments of this system and are therefore should not be considered limiting of its scope, for the system may admit to other equally effective embodiments.
Throughout the drawings, the same drawing reference numerals will be understood to refer to the same elements and features.
The features and advantages of the present proposed system will become more apparent from the following detailed description along with the accompanying figures, which forms a part of this application and in which:
Fig 1: represents ureteral stent in accordance with our present invention;
Fig 2: illustrates the introducer system in accordance with our present invention;
Fig 3: illustrates the method of ureteral stent delivery in accordance with our present invention;
Fig 4: illustrates the ureteral stent and introducer system in accordance to the present invention;
Fig 5: shows the ureteral stent diameter: OD Outer Diameter; ID Inner Diameter; L Length; LD Loop Diameter in accordance to the present invention;
Fig 6: illustrates the stylet hub: OD Outer Diameter; ID Inner Diameter; L Length in accordance to the present invention;
Fig 7: illustrates the transparent sheath: OD Outer Diameter; ID Inner Diameter; L Length in accordance to the present invention;
Fig 8: illustrates the metal stylet: OD Outer Diameter; L Length in accordance to the present invention;
Fig 9: illustrates the mechanism of the loading ureteral stent into introducer system in accordance to the present invention;
Fig 10: illustrates the mechanism of ureteral stent delivery in accordance to the present invention;
REFERENCE NUMERALS
100 Ureteral Stent
200 Introducer System
201 Metal Stylet
202 Transparent Sheath
203 Transparent Sheath Hub
204 Stylet Hub
301 loading the ureteral stent over the diagnostic introducer system and remove the stylet
302 passing a guide wire through the scope and inserting the assembly through the scope over the guide wire and then removing the guide wire
303 removing the said guide wire and then injecting the contrast media to perform retrograde pyelogram
304 holding the introducer sheath and remove the transparent sheath which is visually observed for stent deployment
305 observing the curling of loop at the proximal end and pull the transparent sheath completely
DETAILED DESCRIPTION OF THE INVENTION
The principles of operation, design configurations and evaluation values in these non-limiting examples can be varied and are merely cited to illustrate at least one embodiment of the invention, without limiting the scope thereof.
The embodiments disclosed herein can be expressed in different forms and should not be considered as limited to the listed embodiments in the disclosed invention. The various embodiments outlined in the subsequent sections are constructed such that it provides a complete and a thorough understanding of the disclosed invention, by clearly describing the scope of the invention, for those skilled in the art.
FIG. 1 depicts an embodiment of a ureteral stent 100 of the present invention. The ureteral stent 100 having an elongated portion and having a proximal end and a distal end and a pair of securing members disposed at each end. The elongated portion of the stent is configured to extend throughout the length of an individual’s ureter.
The stent 100 of the present invention is placed into the ureter using a guide wire and the procedure described below.
The device of the present invention has two main components, ureteral stent 100 and introducer system 200. The said introducer system 200 includes a metal stylet 201 that supports the stent 100 loading by avoiding any chance of kinking. The said metal stylet 201 is covered by a transparent sheath 202 which is a radiolucent sheath for contrast media injection and to support the said stent. The introducer system 200 is further provided with a stylet hub provision 204 as to connect to the Luer syringe for contrast media injection. The overlength which is a transparent sheath hub covers the stent length and avoids the leakage of contrast media in between.
The said introducer sheath 202 of the present invention is transparent. The transparent sheath is provided with hub provision for injecting contrast media. The length of the introducer sheath is configured to allow contrast media injection into renal system to check the accuracy of deployment of stent. The introducer sheath and stent are configured in such that both the lumens maintain same patency.
A method of introducing the ureteral stent 100 of the present invention comprises the steps of: loading the stent 100 over the introducer system 200; removing the stylet 204 followed by passing over the scope; passing the guidewire through the scope; inserting the device assembly through the scope over the guide wire; removing the said guide wire and then injecting the contrast media to perform retrograde pyelogram.
This injection is followed by unlocking the hub 204 followed by removing the transparent sheath 202 holding the introducer sheath 203 to visually observe for stent deployment. The deployed stent is examined for curling up of the loop at the proximal end. Then the said transparent sheath is pulled off completely. Now the stent is deployed completely and injecting the contrast media through the introducer sheath is achieved and after confirmation the introducer sheath is removed.
The method of ureteral stent delivery of the present invention includes the introducer system 200 an assembly for delivering contrast media or guide wire and deploying ureteral stent into a patient’s ureter which is achieved in a single step.
The method as illustrated in the Fig. 3 to Fig. 10 of the present invention, the method of ureteral stent delivery comprises the steps of: loading the ureteral stent over the diagnostic introducer system and remove the stylet 301; passing a guide wire through the scope and inserting the assembly through the scope over the guide wire and then removing the guide wire 302; removing the said guide wire and then injecting the contrast media to perform retrograde pyelogram 303; holding the introducer sheath and remove the transparent sheath which is visually observed for stent deployment 304; observing the curling of loop at the proximal end and pull the transparent sheath completely 305.
Fig. 4 illustrates the ureteral stent 100 represents 4A and introducer system 200 represents 4B in accordance to the present invention. As illustrated the ureteral stent 100 has a central elongated hollow body in the form of a length of tube which is to be accommodated in the ureter of an individual. The distal end joins the elongated hollow body of the ureteral stent and the hollow body is in the form of a tube part with a spiral turn. The spiral turns are at both ends of the ureteral stent 100. As illustrated the introducer system 200 may be longer than the ureteral stent and may extend slightly further distally. Significantly c the length of one of the introducer system 200 and the ureter stent is coaxial with one another for implanting the stent into an individual.
The introducer system 200 shown in Fig. 2 will adapt the ureteral stent 100 shown in Fig. 5 in size ranging from 3 Fr to 8 Fr with outer diameter (OD) in the range of 0.95 mm - 2.70 mm and inner diameter (ID) in the range 0.50 mm - 1.45 mm as shown in table 1 below. The stent length can vary from 6 cm to 36 cm.
Table 1:

Stent Size (Fr) Stent OD (mm) Stent ID (mm)
3 0.95-1.05 0.50-0.55
3.5 1.05-1.15 0.50-0.55
3.8 1.10-1.20 0.65-0.70
4 1.20-1.30 0.70-0.75
4.5 1.35-1.50 0.80-0.85
4.7 1.45-1.60 0.90-0.95
4.8 1.45-1.60 0.90-0.95
5 1.60-1.70 1.00-1.05
5.5 1.75-1.85 1.05-1.10
6 1.85-2.00 1.05-1.10
6.5 2.10-2.20 1.10-1.20
7 2.25-2.35 1.20-1.25
8 2.60-2.70 1.35-1.45

A round catheter of 1 French has an external diameter of 1/3 mm and therefore the diameter of a round catheter in millimeters can be determined by dividing the French size by 3:
1 mm = 3 Fr
1 Fr = 1/3 mm
As illustrated in Fig. 6, the introducer system 200 is further provided with a stylet hub provision 204 to connect to the Luer syringe for contrast media injection. Here, the OD represents the outer diameter; ID represents the inner diameter and L length.
As illustrated in Fig. 7, the introducer system 200 is further provided with a transparent sheath 202 is a radiolucent sheath for contrast media injection and to support the said stent. Here, the OD represents the outer diameter; ID represents the inner diameter and L length.
As illustrated in Fig. 8, the introducer system 200 is further provided with a metal stylet 201 which is covered by a transparent introducer sheath 202 and flexible cannula with hub which allows stent loading on the assembly and when removed provides a lumen for accessing over the guide wire insertion. Here, the OD represents the outer diameter and L length.
As illustrated on Fig. 9, the method of ureteral stent delivery comprises the steps of: loading the ureteral stent 100 over the diagnostic introducer system 200 and remove the stylet as illustrated in Fig. 9A and Fig. 9B passing a guide wire through the scope and inserting the assembly through the scope over the guide wire and then removing the guide wire.
As illustrated in Fig. 10, Fig. 10A represents ureteral stent 100 from introducer system 200 and then injecting the contrast media to perform retrograde pyelogram; Fig. 10B illustrates the removal of the metal stylet 201 from transparent sheath 202, removing the transparent sheath is visually observed for stent deployment; Fig. 10C the syringe is connected to the transparent sheath for further processing.
The present invention includes the following improvements:
1. There is no requirement for an extra catheter for contrast media injection.
2. There is no requirement for exchanging catheter/guidewire during the entire procedure.
3. There is no requirement for need of safety wire for securing access.
4. The lab test procedural time is 3 mins 06 sec when compared to the existing Lab testing procedural time of 5 mins 14 sec and hence less chance of infection.
5. There is no requirement for any additional catheter to confirm stent placement.
Throughout this specification various indications have been given as to preferred and alternative embodiments of the invention. It should be understood that it is the appended claims, including all equivalents, that are intended to define the spirit and scope of this invention.