WO2012153007A1

WO2012153007A1 - Medical device for extracting fragments of urinary calculi from the ureter and method for using such a device

Info

Publication number: WO2012153007A1
Application number: PCT/FR2011/000289
Authority: WO
Inventors: Alain Lebet
Original assignee: Alain Lebet
Priority date: 2011-05-11
Filing date: 2011-05-11
Publication date: 2012-11-15

Abstract

The invention relates to a medical device for extracting fragments of urinary calculi from the ureter and to a method for using such a device. The device is characterized in that it comprises irrigation equipment (8, 11) positioned behind the expandable element (2) in relation to the end of the catheter (1) introduced first into the tract, said equipment (8, 11) spraying an irrigation liquid against the expandable element (2) in order to extract the fragments of calculi which flow out of the tract towards the proximal end of the catheter (1) while said element (2) is in the expanded state and at least partially blocking the tract. The invention is suitable for use in the medical field.

Description

"Medical device for extracting urinary stone fragments in the ureter and method of using such a device"

The present invention relates, in general, to a medical device for extracting urinary stone fragments in the ureter as well as the method of using such a device.

More particularly, but in a non-limiting manner, the present invention applies to the extraction of urinary stone fragments outside the ureter.

It is known that many pathways present in the human body are likely to contain fragments of stones or similar objects that can at least partially obstruct them. This is particularly the case of renal stone fragments for the urinary tract or fragments of gallstones for the liver vesicle.

Many surgical devices for the removal of these calculus fragments are known from the state of the art.

For example, WO 01/05311 discloses a device for extracting fragments of gallstones or kidney stones from a human body pathway comprising a catheter provided with first and second expandable equipment, the first for dilating the mouth of said pathway to allow introduction of the catheter therein and the second removing the computational fragments by pushing them towards the mouth of said path, this when the second apparatus is expanded and subjected to traction out of this way.

For such a device, the efficiency of the extraction of the computational fragments by the action of the second expansive apparatus can be weak, the first element having no role in this removal while the second apparatus in the expanded state may not perfectly apply on the walls of the track during its removal from said track and thus ensure efficient extraction of the computational fragments. Conversely, the second expanded equipment can be applied with too much force against the walls and cause injury to this wall.

Such a device is therefore neither perfectly reliable nor safe for the protection of the patient's body. This device should therefore be replaced by or associated with another method of extraction of the computational fragments in order to increase its effectiveness while reducing its dangerousness for the patient. The present invention aims to provide a medical device for efficient extraction of the calculus fragments located in a pathway of the human body, without risk of injury to it.

The present invention also aims to provide such a medical device with a possibility of easy transformation of this device even in use for the addition of an auxiliary apparatus for extraction of computational fragments.

For this purpose, the subject of the invention is a medical device for extracting calculus fragments from a pathway of the human body, this device comprising a catheter with an element expandable externally and transversely to said catheter, characterized in that comprises an irrigation apparatus disposed behind the expansible member relative to the end of the catheter firstly introduced into said pathway, said apparatus projecting an irrigation liquid against the expandable member for extraction of the flow computational fragments out of the way towards the proximal end of said catheter while said member is in an expanded state and at least partially closes said member.

According to additional features of the present invention:

the irrigation apparatus comprises a channel extending longitudinally to the catheter and opening in proximity to the expandable element,

the irrigation channel serves to protect said element in its unexpanded state, said channel then sliding above said element and covering it,

the irrigation channel is connected to a removable connector, this connector being connected to an irrigation liquid reservoir,

the expandable element is an inflatable balloon traversed by the catheter at two diametrically opposite points with a leaktight attachment to said catheter at each of said points, the irrigation channel leading to the attachment of the inflatable balloon opposite to the end of the catheter introduced in first in the way,

the balloon is supplied with inflation fluid by an inflation duct connected to a removable connector, this connector being provided with means for introducing the inflation fluid,

the inflation duct and the irrigation channel extend inside the catheter, said duct and channel extend concentrically, said duct containing said duct and its connector being placed before the connector of said duct with respect to the catheter end introduced first, the external wall of the catheter being formed, on the one hand, by said channel on its intermediate portion between the inflatable balloon and the connector and, on the other hand, by said conduit on its proximal and distal end portions, the proximal end portion extending between the connector associated with said channel and the connector associated with said conduit and the distal end portion extending between the end introduced first in said path and the inflatable balloon,

the device comprises an auxiliary apparatus for extracting fragments of stones, this apparatus comprising a structure that is expandable externally and transversely to said catheter,

said auxiliary apparatus is removably attached to the periphery of the catheter so as to be rapidly mounted on or disassembled therefrom, the expandable structure being, in the mounted position of said auxiliary apparatus, behind the expandable element and at a distance from this one with respect to the end of the catheter introduced first,

the structure is surrounded, on one side, by a fixed element during the deformation of the structure and, on the other, by a movable element during the deformation, the displacement of the movable element relative to the fixed element causing said deformation,

the fixed and mobile elements are respectively in the form of a tube, the two tubes being concentric while surrounding a portion of the catheter and each tube being connected to a respective handle for its displacement, the so-called fixed tube being only displaced during its fixing around the catheter or removing said catheter out of the way,

- The structure is a shape memory alloy, including a nickel alloy and titanium.

The invention also relates to a method for extracting calculus fragments from a pathway of the human body, characterized in that it comprises the following steps:

introduction of a catheter into the pathway, this catheter comprising, from its end introduced first, an expandable element externally and transversely to the catheter followed by an irrigation apparatus, depressing said catheter in the pathway until the computational fragments are between the expandable element and the mouth of said path,

- Projection of a liquid by the irrigation apparatus for extracting computational fragments out of the way flow, this step being combined with an expansion of said element so as to at least partially close said path.

Advantageously, the method for extracting computational fragments comprises an auxiliary extraction step by an apparatus comprising a structure that is expandable externally and transversely to said catheter that captures and / or pushes the computational fragments to extract them from this pathway.

The technical effect obtained by the present invention is to prevent or significantly reduce the projections of irrigation fluid to the front end of the catheter, which avoids the entrainment of computational fragments in the opposite direction of an exit of the way. In addition, as the irrigation is carried out in the portion of the path between expansible element and mouth of this channel, this irrigation is concentrated on the portion of the path likely to contain the fragments of stones and its efficiency is improved. .

Compared to scraped extraction with a retracted solid, the irrigation device according to the present invention allows extraction that does not cause wounding of the lane wall while being more efficient since the solid element of the lane Scraper extraction may not completely follow the inner contour of the lane and thus leave behind fragments of stones when retracted, which is not the case for flow with sufficient irrigation.

The invention will now be described in more detail but in a nonlimiting manner with reference to the appended figures, in which:

FIG. 1 is a schematic representation of the front portion of the extraction device according to the present invention, this front portion being introduced into the patient's lane containing the computational fragments to be extracted, FIG. 2 is a schematic representation of the auxiliary extraction apparatus according to the invention, which is in an unexpanded state,

FIG. 3 is a diagrammatic representation of the auxiliary extraction apparatus according to the invention, the latter being in an expanded state,

FIG. 4 is a diagrammatic representation of the totality of the calculus extraction device according to the present invention, showing in particular the irrigation liquid supply system, the system for actuating the expansion of the expansible element of said device and the operating system of the auxiliary extraction apparatus.

In what follows, the word path generally corresponds to a passage present in the human body and likely to contain undesirable elements to extract.

In the same way, the word calculus corresponds to any undesirable element found in any way of the human body. This element may have been previously fragmented or not.

The present invention will be described in connection with fragments of stones located in the urinary tract, this path may be one or the other of the ureters but this is not limiting. Thus the present invention can also be applied to the bile duct.

Figure 1 shows the front portion of a catheter, having the form of a long flexible and thin tube, this portion being intended to be introduced into a path of the human body. This catheter 1 may advantageously comprise in its interior several longitudinal passages as will be seen later.

In general, all the constituent parts of the catheter 1 and in particular the parts located at the periphery thereof may advantageously have the following characteristics: the metal surfaces of these parts are advantageously polished, in particular by electrolysis, the edges of these parts may have chamfers to reduce the risk of injury to the human pathway to be treated and materials used for their manufacture may be biocompatible. These parts may also have markers or a coating to increase their recognition by a control means, for example by X-rays. The catheter 1 comprises at its end to introduce first into the path of the human body, otherwise known as the distal end, a flexible tip 3 of its end portion. Its other end is called the proximal end.

This flexible tip 3 of this distal end portion advantageously has chamfers at its front face forming the first introduced end of the catheter 1. It may be based on polyurethane (PU) or another material giving it flexibility not to injure the walls of the path in which the catheter 1 is introduced. It also provides a certain rigidity to facilitate the passage of the catheter 1 when obstacles such as fragments of stones are encountered during its insertion into the track. It is also possible to use for its manufacture a shape memory alloy with a high degree of deformation or even stainless steel.

This flexible tip 3 may also include a marker to facilitate tracking of the depression of the catheter 1 in the way.

The flexible tip 3 of the distal end portion is followed by an expandable member 2 shown in Figure 1 in its expanded state. In Figure 1, the expandable member 2 is in the form of an inflatable balloon, which is a preferred embodiment of the present invention but not limiting. The inflatable balloon 2 is traversed at two diametrically opposite points with a tight connection to the catheter 1 at each of these points.

This balloon 2 may advantageously be made of silicone or, secondly, of latex. The balloon material may also be of a synthetic material such as polyurethane, polyethylene or polyamide, for example a nylon.

The balloon 2 is inflated via an inflation duct 7 from an inflation connector which will be detailed in FIG. 4. In FIG. 1, only the inflation duct 7 is visible as well as an opening. 7a inside the balloon 2 for the inflation fluid. For reasons of space saving, it is advantageous to provide a single inflating line 7 instead of two respectively for inflation or deflation.

The inflation fluid may be a gas, for example air, or a liquid. The latter is preferred since it allows a better control of the pressure prevailing in the balloon 2 and requires a smaller volume. This makes it possible to use a means for introducing the inflation fluid such as a syringe instead of a complex device as required by the use of a gas. In the case of X-ray control, while it is advantageous to use an X-ray translucent material for the balloon 2 so as not to hinder the vision of the catheter-coated front end portion of the catheter 1 during its position in the track when said balloon 2 is still in unexpanded state, the inflation fluid advantageously comprises a contrast agent to facilitate the recognition of the balloon 2 X-ray when it is in its expanded state.

The diameter of the balloon 2 in the expanded state can be determined according to the size of the path to be treated. For example, for use in the renal pelvis, a balloon diameter of 8 to 10 mm may be considered. As an indication, the unexpanded and expanded volume ratio between states may, for example, vary from 1/7 to 1/11.

Starting from the front end of the catheter 1 carrying the flexible tip 3, after the expandable member 2 is an irrigation device. In Figure 1, only the outlet end of the channel 11 for irrigation is visible. The irrigation channel 1 may be advantageously concentric with the inflation duct 7 and wrap it by maintaining between them a space for the passage of the irrigation liquid.

Alternatively, the irrigation channel 11 and the inflation duct 7 can extend side by side in the catheter 1.

Through the exit end of the irrigation channel 11 visible in Figure 1, for example all around it, the irrigation liquid is projected towards the expansible element 2. This is illustrated by the arrows F1 and FV. Because the element 2 is in expanded state, the irrigation liquid is stopped by the facing portion of said element 2 and does not reach or reaches weakly the other hemisphere of this element 2 facing the end portion carrying the flexible tip 3.

The same goes for the fragments of stones that could be pushed even deeper into the track in a retrograde motion if it was not at least partially blocked by the element 2.

In the case of an X-ray inspection, it is advantageous to identify the flow of the irrigation liquid in particular by marking, for example with gold.

Thus, in accordance with the present invention, the medical device for extracting calculus fragments from a human body pathway comprises a catheter 1 with an expandable member 2 externally and transversely said catheter 1 being fixed at its periphery. An irrigation apparatus, of which only the end of the irrigation channel 11 is visible, is disposed behind the expandable element 2, taking as reference the end portion of the catheter 1 introduced first into said channel. This irrigation apparatus projects an irrigation liquid towards the expandable element 2 for extraction of the computational fragments by out-of-track flow while said element

2 is in the expanded state and at least partially closes it.

In Figure 1, the route containing the computational fragments and in which the catheter 1 is introduced is not shown. The expansion of the element 2 is calculated to more or less completely obstruct this path, for example by touching the walls thereof, without exerting too much pressure on said walls in order not to damage them. Thus the flow of the irrigation liquid is limited to the portion of the path between the element 2 and the mouth of said channel.

The device according to the present invention can be implemented after lithotripsy but it is not obligatory. This lithotripsy operation aims to fragment the fragments of stones present in the urinary tract. This can be implemented by an endoscopic device and in particular by pulsed laser, via an optical fiber capable of transmitting the energy of a laser radiation to the fragments of computations to be fragmented.

It may also be possible to include in the medical device for extracting calculus fragments according to the present invention an apparatus for this fragmentation and a vision apparatus for monitoring this fragmentation, provided that these two devices are a very small footprint. For example, the catheter according to the present invention may be traversed longitudinally by an optical fiber for transmitting energy from laser radiation to fragments of computations to be fragmented as well as an optical fiber for transmitting radiation. light to monitor the fragmentation operation, these fibers having diameters of the order of a few hundred microns. In this case, the distal end portion of the catheter 1 and its flexible tip

3 allow the uncorking of these fibers so that they can fulfill their role.

According to the method of use of the device according to the present invention, the catheter 1 is introduced into the way with its element 2 in unexpanded state, until the fragments of calculations contained in this way are closer to the mouthpiece that said element 2. Then, the Irrigation fluid is projected to extract the computational fragments out of the way flow, this step being combined with an expansion of said element 2 so as to at least partially close said path.

Alternatively, a cystoscope can also be used for guiding the catheter 1 in the way, which allows its easy insertion, this way being, for example, the ureter. As previously mentioned, the end portion of the catheter 1 with the flexible tip 3 and the element 2, then in unexpanded state, exceed the computational fragments in this way. The distal end portion with its flexible tip 3 is placed in the kidney with the element 2 not yet in expanded state in the renal pelvis. Once this placement is complete, the cystoscope is removed.

Then before or simultaneously with the projection of the irrigation liquid, the element 2 is expanded to prevent or at least partially limit the flow of liquid to the portion of the path between the element 2 and the mouth of said channel, this portion being the one containing the computational fragments to be extracted. ,. , -

In FIG. 1, the catheter 1 also comprises an auxiliary extraction device 4, 5, 6 of calculus fragments, this apparatus comprising a deformable structure 4 transverse to said catheter 1. This auxiliary apparatus 4, 5, 6 is fixed in such a way removable to the periphery of the catheter 1 so as to be quickly mounted on or disassembled therefrom. It should be borne in mind that this apparatus is not an essential feature of the present invention and that it is put in place only when the need arises. Thus, it can be proceeded to its mounting on the catheter 1 when the irrigation extraction of the computational fragments has proved insufficient.

The deformable structure 4 is attached, on one side, to a fixed element 5 and, on the other, to a mobile element 6. It is the movement of the movable element 6 towards the fixed element 5 which causes the deformation of the structure 4 resulting in a transverse expansion with respect to the catheter 1.

As will be seen more precisely later, in particular to the study of FIG. 4, the two fixed and mobile elements 6 may be in the form of concentric tubes, the movable element 6 being slidable above the fixed element 5. The irrigation channel 11 as well as the inflation duct 7 of the expansible element 2 can thus be removably housed in the fixed element 5 in the form of a tube. The deformable structure 4 may be covered with a coating to enhance its visibility during the extraction process, for example when this process is controlled by X-rays.

As a non-limiting idea, for use in a ureter, the catheter 1 of the medical device according to the present invention has a maximum outside diameter of 0.9 mm to 1.2 mm when the element 2 n is not expanded, an inflating conduit 7 with a length of about 1.4 m with an end portion with flexible tip 3 of less than 20 mm and an auxiliary extraction apparatus of about 1 m.

With reference to FIGS. 2 and 3 which show a possible embodiment of the structure 4 of the auxiliary extraction apparatus 4, 5 and 6 respectively in the unexpanded state and in the expanded state, the transverse expansion towards the outside of this structure 4 is obtained during the compression of its length.

Thus, in a preferred embodiment of the structure 4, when the catheter is introduced into the path, the deformable structure 4 occupies an elongated position shown in Figure 2 and corresponding to its unexpanded state. Therefore, in this form, the deformable structure 4 does not hinder the depression of said catheter in the pathway. When the length of the deformable structure 4 is reduced by compression, as shown in FIG. 3, the structure 4 is deformed and tends to expand transversely to the catheter while the shape of the fixed and mobile elements 6 remains unchanged.

The fixed and movable elements 6 and 6 can be made of stainless steel. They can also be made of a plastic material having similar properties to metallic materials. A polyetheretherketone (PEEK) is preferred because this semi-crystalline plastic has a very good chemical resistance as well as wear and a good sliding behavior.

The material of the deformable structure 4 may be a stainless steel. However, it is preferred to use a shape memory alloy, that is to say an alloy having the capacity to keep in memory an initial shape and to return to it even after deformation. These alloys are generally based on nickel and titanium being grouped under the name of nitinol but not only because alloys other than nickel-based and titanium-based have shape memory properties and can be used.

It should be borne in mind that the nitinol group is not reduced to the equal titanium-nickel alloy and may also include alloys with different nickel and titanium contents. As shape memory alloys comprising elements other than nickel or titanium, there may be mentioned for example without being limited to alloys based on copper, aluminum and nickel and alloys based on copper, zinc and aluminum.

In the case of a deformable structure 4 of shape memory alloy, this can be made from a tube of said alloy which has been cut into longitudinal strips from one end of the tube, these strips not reaching the other end of the tube. This gives a structure 4 which, connected on one side to the fixed element 5 and the other to the movable element 6, has in the expanded state curved strips. However, this solution has the disadvantage of using a shape memory alloy tube, for example a nitinol, which implies a high cost due to the manufacture of this tube. In addition, the strips can be bent differently, which gives a section in the expanded position of the structure 4 does not have a circular contour.

Thus, it is preferred to use a mat-like structure 4 composed of shape memory alloy wires, for example one. nitinol type alloy. It is possible by changing the number of wires used and / or by taking alloy wires of different thicknesses to obtain a more or less rigid structure. This preferred solution allows an adaptation of the structure 4 to the parameters of its future use, obtaining a circular contour and a lower cost than for the manufacture of a tube. However, this solution may cause a difficulty of fixing the end of the son of the alloy associated respectively with the fixed element 5 or the movable element 6.

This structure 4 also has a certain rigidity in the expanded position in order to maintain its external shape and to be able to capture and / or drive the fragments of stones present in the path to be treated. In the case of a 4-wire structure, its mesh is sufficiently narrow for capturing fragments of stones, this structure 4 thus serving as a basket of imprisonment of certain fragments of stones between its mesh.

The structure 4 must, however, be deformable when subjected to a force exceeding a predetermined force that may correspond to damage to the path to be treated, for example rupture of the urethra.

The wire structure 4 can for example be fixed to the movable elements 6 and fixed 5 metal, for example stainless steel or a plastic with properties similar to a metal clamping, gluing, soldering or welding. A respective cavity can be arranged on the element 6 and on the fixed element 5 to allow the attachment of the corresponding end portion of the structure 4. Rounded son are advantageous to avoid the risk of injury to the track. In addition, especially in the case of an X-ray positioning control, the structure 4 may be coated with a marking agent.

The structures 4 of shape memory alloy, in particular nitinol, can be essentially of three types, each type corresponding to a predetermined form to restore.

In the first type, the structure 4 tends to return to the shape it occupies in its expanded state as shown in FIG. 4. During insertion and insertion of the catheter into the path to be treated, the operator applies then an axial force on the structure 4 tending to move the movable element 6 away from the fixed element 5 in order to lengthen this structure 4 and reduce its diameter. The rigidity of such a structure 4 is high.

In the second type, the structure 4 tends to return to the shape it occupies in an intermediate position of its expanded state. The operator applies an axial force on the structure 4 tending to move the movable element 6 away from the fixed element 5 when it wishes to lengthen this structure 4 and reduce its expanded diameter. The rigidity of such a structure 4 is low.

In the third type, the structure 4 tends to return to the shape it occupies in its unexpanded state as shown in FIG. 3. The operator applies an axial force to the structure 4 tending to bring the movable element 6 closer to the fixed element 5 when it wishes to increase the expansion of said structure 4.

In Figures 2 and 3, it is this third configuration that has been chosen. and this is preferential. This however is not limiting and the other two configurations are also possible.

Figure 4 shows the complete form of the medical device for extraction of computational fragments according to the present invention.

In this figure, the portion of the device surrounded by the circle C1 is that which has been illustrated in FIG. 1 while the rest of FIG. 4 makes it possible inter alia to detail the characteristics of the system for actuating the expandable element of said device as well as the irrigation fluid supply system.

With regard to the system for actuating the expandable member in the form of a balloon 2 in this figure, it comprises a inflation duct 7, as already mentioned in the part of the description relating to FIG.

Said duct 7 extends substantially over the entire length of the catheter 1, advantageously crossing on both sides the balloon 2 and forms the central element of said catheter 1. It is in the form of a thin-walled tube, preferably made of stainless steel and conducts the inflation fluid of an introduction means 12 for this fluid to the balloon 2. This inflation duct 7 is advantageously flexible but nevertheless retains sufficient rigidity, which allows easy guiding of the catheter 1.

Alternatively, it is also possible to use a metal alloy, including a shape memory alloy or a plastic for its manufacture.

At its part in the balloon 2, the inflation duct 7 advantageously comprises two recesses, one of which was shown in FIG. 1 under the reference 7a to allow the introduction of the inflation fluid into this balloon 2. When the balloon 2 is traversed on either side by this duct 7, as shown in FIG. 4, the end of said duct 7 forms the front end, called the distal end, of the catheter 1 and is closed by the flexible endpiece 3, which protects the conduit 7 against the unwanted introduction of material during the depression of the catheter 1 in the way to be treated of the human body.

The other end of the inflation duct 7, forming the proximal end of the catheter 1, is connected and extended by a removable connector 9, preferably with two valves, this connector 9 for connecting said duct 7 to an introduction means 12 inflation fluid, for example in the form of a syringe. This introduction means 12 can be advantageously graduated. Said end of the inflation duct 7 is sealed to the connector 9 to prevent loss of the inflation fluid, this inflation fluid being preferably a liquid, as previously mentioned.

It has also been mentioned that an auxiliary extraction apparatus may also be mounted on the catheter. This involves the disassembly of the connector 9 and it is advantageous that this disassembly is simple to perform.

Advantageously, the connector 9 of the inflation apparatus has a Y-shape, one of the branches of ΙΎ carrying the introduction means 12 of the inflation fluid into said apparatus and the other forming the proximal end of the catheter 1. When dismantling connector 9, a needle-shaped tool is inserted into the inflating conduit 7 to effect its occlusion while the connector 9 is removed. The balloon 2 consequently remains inflated during this operation.

As shown in Figure 1, the device according to the invention also comprises an irrigation system for extracting computational fragments out of the way to be treated.

This irrigation system comprises the previously mentioned irrigation channel 11 concentric with inflation duct 7 and receiving it. This channel 11 may advantageously be made of plastic, in particular polytetrafluoroethylene (PTFE), polyetheretherketone (PEEK) or polyurethane (PU). However, it is also possible to use a shape memory alloy or a stainless steel for its manufacture.

The irrigation channel 11 is used for conveying the irrigation liquid from an end 8a of a connector 8, preferably removable and going to the end of said channel 11 facing the balloon 2, whereby this liquid irrigation is projected against said balloon 2. The connection between connector 8 and channel 1 1 is advantageously sealed. The other end 8b of the connector 8 is connected to the inflation duct 7 which passes therethrough and enters the irrigation channel 11. On the other hand, the connector 8 is advantageously connected to the source of irrigation liquid. This is done between the two ends 8a and 8b of the connector 8, preferably by a lockable screw cap for closing the connector 8 securely.

This source may be in the form of an irrigation liquid reservoir. The liquid supply can be active or passive. In the first case, a pump or a mechanical device is used for the delivery of the liquid in the irrigation channel 11. This may allow adjustment of the liquid flow rate by control equipment, including electronic equipment. In the second case, a tank is used, which may have an adjustable flow valve and the flow of the irrigation liquid is by gravity. This second option is preferred.

Advantageously, during the introduction and depression of the catheter 1 in the path, the end portion of the irrigation channel 11 facing the balloon 2 then in an unexpanded state can serve as a protection for the latter by receiving it internally, since this could be damaged when exceeding the fragments of stones present in the track. This protection is advantageously effected by sliding the irrigation channel 11 around the unexpanded balloon 2. When the catheter 1 is positioned in the way, this protection is removed, advantageously by retraction of the channel 11 from its covering position of the balloon 2 and the latter may be liable to be inflated.

Alternatively, a protection element can be added to the device according to the invention. This element can be metal or plastic.

The diameters of the irrigation channel 11 and the inflation duct 7 should be determined to optimize the operation of the extraction device according to the present invention.

The first limiting factor is the diameter of the catheter constituting the device which must not be much greater than that of the channel in which it has to be introduced.

Conversely for the determination of the respective diameter of the channel 11 or the duct 7, it is to be considered that they have to have a minimum diameter to ensure their respective function of irrigation or inflation, this in an acceptable time. Since the duct or channel is of great length, high friction occurs between the inflation or irrigation fluid and the walls of the duct or channel. By taking into account the length of the channel or duct and the desired duration to achieve balloon inflation or satisfactory irrigation, tests may determine a minimum inside diameter of said duct or channel.

A reduced space can be left between the inflating duct 7 and the irrigation channel 11. In this case, the respective passage area for the irrigation or inflation liquid is decreased, which may have a disadvantage. This is not preferred unless circumstances oblige.

For setting up auxiliary extraction equipment 4, 5, 6,

10a and 10b on the catheter 1, the connector 8 of the irrigation apparatus is also to be disassembled, preferably in a manner that is simple to carry out and this without interrupting the supply of irrigation fluid carried out via the channel 11 and the inflation fluid supply being effected by the tube 7.

For the design of the irrigation and inflation systems, as alternatives to the use of a concentric irrigation channel to an inflating conduit and receiving it, it can be envisaged to use more than one channel in the same catheter. one or two of these channels serving respectively to inflate and deflate the balloon, the other channels serving for irrigation.

Conversely, it may also be considered to combine irrigation and inflation in a single conduit. This embodiment however requires the presence of a valve between said channel and the balloon so that stop inflating once a determined pressure reached in it and then use the conduit liquid for irrigation.

These two embodiments are not preferred, unlike that comprising a channel and a concentric duct described in Figures 1 to 4 of the present application.

Without this being in any way obligatory, it may be possible to add to the medical device according to the invention a device for suctioning the irrigation fluid coming from the portion of the channel between the expandable element 2 and the mouth of said channel, to facilitate the removal of computational fragments driven by this fluid.

This suction apparatus not shown in the figures, can penetrate inside the track but this is not necessarily the case. On the contrary, advantageously, its or its suction means, for example one or conduits, may be arranged against the mouth of the channel outside thereof. This apparatus may be totally independent of the medical device according to the present invention or be connected thereto, for example by extending along its outer contour to the proximal end of the catheter 1 or even being integrated in the device catheter. This latter option is not preferred because the compactness of the medical device is no longer strongly required outside the pathway.

FIG. 4 also shows the mechanism for controlling the movement of the movable element 6 with respect to the fixed element 5 for the operation of the auxiliary extraction apparatus. The element 5 is said to be fixed because it does not move during the deformation operation of the structure 4. However, this fixed element 5 is displaced during assembly of the apparatus around the catheter 1 or the catheter extraction 1 out of the way to deal with.

The movable and stationary elements 5 are in the form of concentric tubes which are concentric with each other and concentric with the inflation duct 7 and with the irrigation channel 11, the tube of the fixed element 5 being inside the tube of the movable element 6, as shown in Figure 4 but the opposite is also possible.

Outside the path to be treated and at a distance from its mouth, the tube of the movable element 6 is attached to a movable handle 10a allowing the operator to slide said tube on the tube of the element. fixed 5. It completely traverses the movable handle 10a and is attached to a fixed handle 10b located between the movable handle 10a and the irrigation connector 8. The operation of the movement control mechanism of the extraction apparatus may be as follows:

During assembly, after disassembling the irrigation connector 8 and the inflation connector 9, the handle assembly 10a, 10b and tubes 5, 6 are slid from the proximal end of the catheter 1 to the conduit first. inflating 7 and the irrigation channel 11 until an adequate positioning of the structure 4, maintained in an undistorted state, within the path to be treated. The connectors 8 and 9 are then put back in place.

Upon activation of said apparatus, the tube of the movable member 6 is pushed towards the channel to be treated by action on its handle 10a in this direction. This compresses the structure 4, placed inside the lane, and expands it externally and transversely with respect to the catheter 1 as it has been shown in FIG.

As previously mentioned, this transverse deformation can be controlled by an adequate control means, in particular by X-rays.

For the extraction step itself, it is the handle 10b of the fixed element 5 which is pulled away from the track, so that the structure 4 makes an exit movement towards the mouth of the track . During this step, the handle 10a of the movable element 6 is also pulled to perform a movement similar to that of the handle 10b and so that the deformation of the structure 4 remains the same, unless it is appropriate to change the transverse expansion of said structure 4, for example when the contour of the path to be treated varies in size. The fragments of calculations retained in the structure 4 and / or driven by it then leave the track with the extraction apparatus.

Other ways of triggering the deformation of the shape memory alloy structure than using fixed and moving element handles can be envisaged. For example, as these alloys have the ability to alternate between two forms previously stored when the temperature varies around a critical temperature, the expandable structure implemented may be a shape memory alloy sensitive to the difference between the temperatures prevailing in the way respectively with or without irrigation.

This is only possible when there is a significant difference between the internal temperature of the human body and the temperature of the irrigation liquid with the additional condition that this difference is not harmful to the human body. Tests can determine which minimum temperature difference between that of the channel and that of the irrigation fluid can trigger the deformation as well as the shape memory alloy having the strongest response to such a difference.

Claims

A medical device for extracting urinary calculus fragments from the ureter of a human body, which device comprises a catheter (1) with an element (2) expandable externally and transversely to said catheter (1), characterized in that it comprises an irrigation apparatus (8, 11) disposed behind the expansible element (2) with respect to the end of the catheter (1) introduced first into the ureter, said apparatus (8, 11) projecting an irrigation liquid against the expandable member (2) for extracting computational fragments by flow out of the ureter towards the proximal end of said catheter (1) while said element (2) is in a state expanded and at least partially closes thereof, the irrigation apparatus (8, 11) comprising a channel (11) extending longitudinally of the catheter (1) and opening on the expandable element (2).

2. Device according to claim 1, characterized in that the irrigation channel (11) serves to protect said element (2) in its unexpanded state, said channel (11) then sliding above said element (2) and the covering.

3. Device according to claim 2, characterized in that the irrigation channel (11) is connected to a connector (8) removable, this connector (8) being connected with a reservoir of irrigation liquid.

4. Device according to any one of claims 2 or 3, characterized in that the expandable element (2) is an inflatable balloon through which the catheter (1) at two diametrically opposite points with a leaktight attachment to said catheter (1) at each of said points, the irrigation channel (11) leading to the attachment of the inflatable balloon (2) opposite the end of the catheter (1) introduced first into the ureter.

5. Device according to the preceding claim, characterized in that the balloon (2) is supplied with inflation fluid by an inflating conduit (7) connected to a connector (9) removable, this connector (9) being provided with a means for introducing (12) the inflation fluid.

6. Device according to the preceding claim, characterized in that the duct (7) for inflation and the irrigation channel (11) extend inside the catheter.

(1) ·

7. Device according to claims 3 and 6, characterized in that said duct (7) and said channel (11) extend concentrically, said channel (11) containing said duct (7) and its connector (8) being placed before the connector (9) of said conduit (7) relative to the end of the catheter (1) introduced first, the outer wall of the catheter (1) being formed, on the one hand, by said channel (11) on its portion intermediate between the inflatable balloon (2) and the connector (8) and, on the other hand, by said conduit (7) on its proximal and distal end portions, the proximal end portion extending between the connector (8) associated with said channel (11) and the connector (9) associated with said conduit (7) and the distal end portion extending between the end inserted first into the ureter and the inflatable balloon (2).

8. Device according to any one of the preceding claims, characterized in that it comprises an auxiliary extraction apparatus (4, 5, 6, 10a, 10b) of calculus fragments, this apparatus (4, 5, 6, 10a, 10b) comprising a structure (4) expansible externally and transversely to said catheter (1).

9. Device according to claim 8, characterized in that said auxiliary equipment (4, 5, 6, 10a, 10b) is removably attached to the periphery of the catheter (1) so as to be quickly mounted on or removed from the here, the expandable structure (4) being, in the mounted position of said apparatus (4, 5, 6, 10a, 10b), behind the expandable element (2) and at a distance from the latter with respect to the end catheter (1) introduced first.

10. Device according to any one of claims 8 or 9, characterized in that the structure (4) is surrounded, on one side, by a fixed element (5) during the deformation of the structure (4) and, de the other, by a movable element (6) during the deformation, the displacement of the movable element (6) with respect to the fixed element (5) causing said deformation.

11. Device according to claim 10, characterized in that the fixed and movable elements (5, 6) are respectively in the form of a tube, the two tubes being concentric by surrounding a portion of the catheter (1) and each tube being connected to a respective handle (10a or 10b) for its movement, the so-called fixed tube being only moved when it is fastened around the catheter (1) or the extraction of said catheter (1) out of the ureter.

12. Device according to any one of claims 8 to 11, characterized in that the structure (4) is a shape memory alloy, including a nickel alloy and titanium.

13. A method for extracting urinary calculus fragments from the ureter of a human body, characterized in that it comprises the following steps:

- introduction of a catheter (1) in the ureter, the catheter (1) comprising, from its end first introduced, an expandable element (2) externally and transversely to the catheter (1) followed by an apparatus of irrigation (8, 11),

- Depressing said catheter (1) in the ureter until the computational fragments are between the expansible element (2) and the mouth of the ureter, - Projection of a liquid by the irrigation apparatus (8, 11) for extracting the computational fragments by flow out of the ureter, this step being combined with an expansion of said element (2) so as to close at least partially the ureter.

14. A method of extracting calculus fragments according to the preceding claim, characterized in that it comprises an auxiliary extraction step by an apparatus (4, 5, 6, 10a, 10b) comprising a structure (4) expansible externally. and transversely to said catheter (1) sensing and / or pushing the computational fragments to extract them from the ureter.