WO2014128742A1

WO2014128742A1 - Modular forceps for endoscopic biopsy

Info

Publication number: WO2014128742A1
Application number: PCT/IT2014/000052
Authority: WO
Inventors: Mario Immacolato Paternuosto
Original assignee: Mario Immacolato Paternuosto
Priority date: 2013-02-25
Filing date: 2014-02-25
Publication date: 2014-08-28
Also published as: ITCE20130002A1

Abstract

A biopsy forceps, of the type in which closing of the jaws is obtained with a constriction mechanism, can be easily and rapidly taken apart in the form of two modules, one disposable and the other re-usable. The first module comprises a flexible cannula, with its non-flexible more distal stretch that is closed by a plug and presents a longitudinal through slit of appropriate length passing and sliding through which is a preferably steel wire that is appropriately fixed to the inner wall of a sleeve, which is external and coaxial to said non-flexible stretch. The second module is made up of two jaws, one of which is provided with a central protuberance and the other with a bag, of the shanks of the jaws, and of a base, constituted by a cylindrical element of a diameter equal to that of the plug that closes the lumen of the mother cannula. The two modules are rendered fixed with respect to one another by means of a purposely provided anchorage that, in a preferred embodiment, is represented by an ordinary screwing system, so that, once the biopsy operation is through, the jaws with the bag full of mucosal specimens can be detached and sent on to the histologist, whilst a new pair of jaws is fixed on the tip of the first module.

Description

MODULAR FORCEPS FOR ENDOSCOPIC BIOPSY

DESCRIPTION SUMMARY OF THE INVENTION

The present invention relates to the field of endoscopy and more precisely to a biopsy forceps of the type in which closing of the cups or jaws is obtained with a constriction mechanism, characterized in that it can be put together and taken apart in the form of two modules, the first of which, represented by the part of the biopsy forceps that does not come into contact with the mucosa of which a sample is to be taken (handle and cannula) is sterilizable and re-usable, whereas the second part, which comes into contact with the mucosa and comprises the pair of cups or jaws that carry out sampling, is disposable, being releasable from the first module after each sampling operation and being easy to replace.

In this way, there is achieved the result of providing a modular system for implementing bioptic techniques that combines and integrates the two concepts of re-usability and disposability, with a drastic effect as regards reduction of costs.

FIELD OF APPLICATION AND IMPORTANCE OF THE PROBLEM

The accuracy of an endoscopic diagnosis necessarily involves biopsy. Biopsy is the most frequent operation in endoscopy. It envisages getting the forceps for endoscopic biopsy to pass through the operating channel of the endoscope and taking two samples of mucosa for histological examination. At the end of the two sampling operations, the biopsy forceps must be removed, emptied of the two specimens and then reinserted for further sampling. The biopsy forceps may be re-usable or disposable.

Today, the disposable version is increasingly asserting itself.

DESCRIPTION OF THE PRIOR ART

A first traditional biopsy forceps is substantially constituted by two cups or jaws positioned at the end of a metal cannula inside which steel pull wires are located that enable, through articulated mechanisms, closing and opening of the jaws themselves. Another type of biopsy forceps enables closing of the jaws by means of a constriction technique: the more distal stretch of the cannula in which a steel wire of suitable thickness slides is coaxial with a short tubular metal structure or sleeve, with respect to which the aforesaid steel wire that comes out of the tip of the cannula is fixed. Advance of the sleeve constricts together the shanks of the jaws fixed with respect to the tip of the cannula and forces them to close.

According to the current state of the art, a biopsy forceps of this sort, whatever the mechanism of closing of the jaws, can take at most two samples of mucosa.

To highlight the importance of the invention described, we shall restrict our considerations to the gastroenterological field where it immediately emerges that the possibility of taking multiple samples in a short time has always represented not a desire, but a need, for the endoscopist. There exist some pathological conditions, such as for example ulcerative pancolitis, where it is necessary to carry out a biopsy on the intestine every ten centimetres, taking a specimen for each of the four quadrants. There is thus the need to get the biopsy forceps to pass a number of times through the operating channel of the endoscope, thus accelerating the process of wear. The operating channel of the endoscope will first end up by distending electively in the stretches that can be flexed and will then break, and the apparatus will end up being infiltrated, with considerable damage. The cases where it is required to have available a biopsy forceps that it is not necessary, after use, to pull out of the channel of the endoscope, to empty of the histological specimens, and then to reintroduce into the channel are the ones that present in the characterization of Barrett's syndrome of the distal stretch of the oesophagus. In this peculiar case, since the stretch of mucosa of the distal oesophagus is conspicuously irrigated, there will be copious bleeding after the first biopsy, and consequently rapidity in taking a number of samples in sequence is important before bleeding obscures the field.

In an attempt to maintain a clear picture, the operator is forced to inject water through the endoscope. If the patient is only slightly sedated there arises a marked intolerance because the jet of water distends the oesophagus and induces precordialgia . The liquid content of the stomach increases and by flowing back into the oesophagus can induce aspiration pneumonia.

To solve the problem of multiple biopsies the present applicant has already filed a patent regarding a biopsy forceps in which one of the jaws was provided with a bag. However, this biopsy forceps presented a problem both of a technical nature in so far as it was not provided with a mechanism capable of channelling the specimen of mucosa sampled, towards the bag and a problem of a commercial nature in so far as this forceps had to be disposed of in its entirety after use .

The task of the present invention is to tackle and solve both of the above problems by providing a biopsy forceps of the type in which closing of the jaws is obtained with a constriction mechanism, where the biopsy forceps can be easily and rapidly taken apart in the form of two modules, one of which is disposable and the other re-usable, which enables the module that contains the samples deposited in a suitable bag contains to be sent on directly to the histologist, thus preventing the paramedical staff from having to bother about emptying the bag or the jaws of the histological samples taken, whereas the rest of the forceps is perfectly sterilizable and can be re-used a number of times.

According to the invention, the first module is represented by a flexible cannula, which in what follows will be referred to as "mother cannula", with the non-flexible more distal stretch that is closed by a plug and presents a longitudinal through slit of appropriate length, passing and sliding through which is a steel wire that is appropriately fixed to the inner wall of a sleeve set external to and coaxial with respect to said non-flexible stretch.

The second module is made up of: two cups or jaws, one of which is provided with a central protuberance and the other with a bag; the shanks of the jaws; and a base constituted by a cylindrical element having a diameter equal to that of the plug that closes the lumen of the mother cannula.

The shanks of the jaws have the sole function of connecting the jaws to the cylindrical base.

The angle formed by the shanks towards their base is such as to maintain an appropriate distance between the jaws and to cause, at the moment of constriction of the shanks and consequent closing of the jaws, a large tissue specimen to be captured. Advantageously, the angle of the shanks with respect to the respective jaws is such that, upon final closing, the edges of the jaws come to be parallel to one another.

The two modules are rendered fixed with respect to one another by means of a purposely provided anchorage, which, in a preferred embodiment, is represented by an ordinary screwing system so that, once the biopsy operation has been carried out, the jaws with the bag full of mucosal specimens can be detached and sent on to the histologist whilst a new pair of jaws is fixed on the tip of the first module. It is possible, for example, to envisage that the base of the second module is provided with a threaded protrusion that is received into a complementary threaded cavity positioned at the centre of the plug. that occludes the lumen of the mother cannula of the first module.

These two elements that enable mutual screwing may also be reversed.

Forming another characteristic of the invention is the different size of the two jaws, which enables the jaw provided with the threaded protrusion to penetrate into the jaw provided with the bag by a pre-set and appropriate depth so as to deposit the histological specimen in the bag in a more harmonious and effective way given that the vectors of thrust on the mucosal specimens are uniform and vertical.

Further characteristics and advantages of the invention will emerge clearly from the ensuing detailed description with reference, merely by way of non- limiting example, to the annexed plates of drawings, which represent a preferred embodiment thereof and in which:

Figures 1 and 2 show the operating positions of a biopsy forceps according to the prior art, which is represented schematically and not in scale, where closing of the jaws is obtained through a constriction mechanism;

Figure 3 illustrates, once again schematically and not in scale, a preferred embodiment of the modular forceps according to the present invention; Figures 4 and 5 show the forceps of Figure 3 before and after sampling, respectively; and

Figure 6 shows a second embodiment of the forceps, where the slots present in the mother cannula are two.

DETAILED DESCRIPTION

Figures 1 and 2 show a biopsy forceps according to the current state of the art, where closing and opening of the jaws 1, positioned at the end of a metal cannula 6, is obtained thanks to the arrangement that envisages that coaxially sliding on the outside of the more distal stretch of the cannula 6 itself is a short metal tubular structure or sleeve, fixed with respect to which is a steel wire 7 that comes out of the tip of the cannula 6.

Advance of a cylinder 3 causes constriction of the shanks of the jaws, which are fixed with respect to the tip of the cannula, and thus forces the jaws to close.

According to the prior art, a biopsy forceps of the above sort, whatever the mechanism of closing of the jaws, can capture at most two mucosal specimens.

Figures 3 onwards illustrate the present invention. As may be seen, it is constituted by a biopsy forceps in which closing of the jaws is obtained by a constriction mechanism, said forceps presenting in the form of two modules that can be assembled easily and rapidly.

The first module is represented by a metal cannula 6 referred to herein as "mother cannula".

The second module is represented by the jaws 8a and 8b and by their shanks that fix them to a metal is provided with a bag 15, whereas the jaw 8b is provided with a swelling or protuberance 16.

The mother cannula 6 has a handle (not represented) that enables closing or opening of the jaws to be governed through a preferably steel wire 7 and is made up of a flexible part and a small non- flexible distal stretch. According to a characteristic of the present invention, the distal stretch of the mother cannula, i.e., the non-flexible one, has a longitudinal through slit 14, of a suitable length, passing and sliding through which is the steel wire 7.

The distal stretch of the mother cannula 6, i.e., the non-flexible one, is comprised in a short tubular metal structure or sleeve 5, with respect to which the steel wire 7 is fixed. The latter, by sliding in the slit 14, pushes the sleeve 5 forward until the shanks of the jaws 8a and 8b are constricted, thus bringing about closing of the jaws. When the wire 7 is pulled back,, it causes opening of the jaws.

The shanks of the jaws merely have the function of connecting the jaws themselves to the cylindrical base 9. The angle formed by the shanks towards their base is such as to maintain an appropriate distance between the jaws and to enable, upon constriction of the shanks and consequent closing of the jaws, a large tissue specimen to be captured.

The base 9 is represented by a cylindrical element having a diameter equal to that of the lumen of the mother cannula, which is provided at the centre, on the side opposite to that of the jaws, with a threaded protuberance 10 that enables it to be screwed into the threaded cavity 11 made in the metal plug 12 that closes the lumen of the mother cannula 6. On the side of the jaws, the base 9 is provided at the centre with an appropriate groove for receiving the tip of a device with which it is possible to bring about rotation in a clockwise direction to enable fixing of the second module to the first or in a counterclockwise direction to enable release thereof. In this way, after the biopsies have been carried out quickly and easily it is possible to detach the first module from the second.

It should be noted that the use of modified jaws provided with a bag has already been proposed in prior documents by the present applicant. According to said solution, in one jaw the concavity is partially removed by the presence of a hump that is designed to cause deformation of the histological specimen and in the other jaw a bag is provided that receives the histological specimen that has undergone deformation by the hump. When the jaws close, the jaw provided with the bag receives the histological specimen that the hump of the controlateral jaw has caused to take on a hemispherical shape. By Hooke' s law F = -kx, once the vector of thrust that the hump of the jaw exerts on the specimen ceases, on account of the elasticity of the tissue sampled the histological specimen will tend to return to its original shape, thus exerting a lateral thrust that increases the friction on the wall of the bag and prevents it from being sucked back out of the bag.

In this known type of biopsy forceps, however, the mechanism of opening and closing of the jaws is obtained by the action of two pull wires that act on the opposite arms of an X-shaped metal structure; this not only conditions balanced filling of the bag thus jeopardizing positioning of the subsequent specimens but hinders the effect of elastic return according to Hooke's principle.

A second disadvantage is the questionability as to whether . it is possible to sterilize the bag of effectively and the actual tolerance of the bag to thermochemical treatment, with the result that the device can only be used once.

The drawbacks of the above forceps for endoscopic biopsy provided with a bag are completely overcome by the inventive · solution according to the present disclosure, which, by resorting to a mechanism of closing of the jaws by constriction and to separation of the jaws from the mother cannula, enables on the one hand modularity and on the other a different and harmonious conveyance of the histological specimen towards the mouth of the bag.

To optimize the above mechanism, in a preferred embodiment, it is possible to produce the two jaws 8a and 8b with the surfaces of action of different size. With this solution, with a suitable angle between the jaws and their shanks and between the shanks and their base, upon final closing of the jaws the latter are parallel to one another. Furthermore, since in the preferred embodiments the jaw 8b, i.e., the one provided with the protuberance 16, has a size similar to, but not the same as, the jaw 8a provided with the bag 15, the former can penetrate into the latter.

Consequently, when the biopsy forceps is closed, the jaw 8b with the protuberance 16 penetrates more or less in depth into the jaw 8a in such a way as to accompany the histological specimen right into the bag 15. There is, in other words, one jaw that functions as an actual piston proper while the other functions as a cylinder.

To sum up, the differences between the present invention and other biopsy forceps, even ones using the constriction mechanism for closing the jaws, are listed below.

1) One of the jaws is provided with a bag and the other is in any case modified.

2) The two jaws are both fixed by means of appropriately shaped shanks to a metal base provided with a system for engagement to and release from the rest of the forceps.

3) The two jaws do not have the same size so that, upon closing, the jaw provided with the protuberance can penetrate into the one provided with the bag.

4) The shanks of the two jaws are simple steel wires of suitable thickness or may even be ribbon- shaped, but do not have the shape of a concave ribbon because they are not required to perform any function of containment of histological specimens.

5) The steel wire that, by pushing the metal sleeve that envelops the non-flexible distal stretch of the cannula, enables the mechanism to carry out constriction, passes through a suitable slit of appropriate length formed in the non-flexible stretch of the flexible cannula.

6) Whereas in forceps according to the .prior art that use the constriction mechanism the mother cannula, which has a flexible stretch and a non-flexible terminal stretch, has the tip open, in so far as the metal wire that actuates the cylinder that creates the noose is made to pass through the tip of the mother cannula, in the forceps according to the present invention the mother cannula, in its non-flexible distal stretch, is closed by a metal plug. Present in this metal plug are engagement and release means that co-operate with complementary means present in the metal base with respect to which the two jaws are fixed by means of shanks.

From what has been described so far, the advantages that the present invention affords are evident :

1) The present invention is conceptually a modular system that combines and harmoniously integrates and realises the two concepts of re-usability and disposability .

2) The first module represented by the handle, the flexible cannula, and its non-flexible stretch is perfectly sterilizable and re-usable; the second module is disposable and must be sent on to the histologist in so far as it contains the samples deposited in the bag. 3) The second module can be rapidly detached from the first module and replaced.

4) This system prevents the paramedical staff from having to bother about emptying the bag or the jaws of the histological. specimens that have been sampled.

5) It is possible to prepare a package constituted by the sterilizable and re-usable component (first module) and by a number, variable according to the preferred commercial and production choices, of the disposable component (second module) .

Claims

1) An endoscopic biopsy forceps of the type comprising a handle provided with control means, a flexible cannula (6), and two jaws (1) that carry out sampling of the histological specimen and are positioned at the end of the cannula, where closing of the jaws is obtained with a constriction mechanism comprising an outer sleeve (5) that is able to slide on the terminal stretch of said cannula, said biopsy forceps being characterized in that it is constituted by two modules that can be put together and taken apart, where the first module, represented by the part of forceps that does not come into any contact with the mucosa (handle and cannula) , is sterilizable and re- usable, whereas the second module, which comes into contact with the mucosa and comprises the pair of jaws (8a and 8b) that carry out sampling, is disposable, being releasable from the first module after each sampling and easily replaceable; wherein:

the first module comprises the flexible cannula

(6) , referred to as "mother cannula", with the non- flexible more distal stretch that is closed by a plug (12) and that presents a longitudinal through slit (14) of appropriate length passing and sliding through which is a wire (7) , which is appropriately fixed to the inner wall of the sleeve (5) of the constriction mechanism, said sleeve being external and coaxial to said non-flexible stretch and governing displacement thereof; and

the second module is made up of the sampling jaws (8a and 8b) fixed by means of shanks to a base (9) constituted by a cylindrical element having a diameter equal to that of the plug (12) that closes the lumen of the mother cannula,

the two modules being rendered fixed with respect to one another by anchorage means (10, 11) that enable rapid detachment so that, once the biopsy operation is through, the jaws with the bag containing the mucosal specimens can be detached and sent on to the histological examination, whilst a new pair of jaws is fixed on the tip of the first module for further biopsies .

2) The endoscopic biopsy forceps as per Claim 1, characterized in that said anchorage means (10, 11) are co-operating screwing means positioned, respectively, on the outer wall of the plug (12) that occludes the tip of the mother cannula (6) in the first module and on the bottom face of the base (9) of the second module .

3) The endoscopic biopsy forceps as per Claim 1, characterized in that the shanks of the jaws (8a and 8b) are fixed in points of the base (9) of the second module that are diametrally opposite to one another, and are of an appropriate length to enable symmetrical closing of the jaws themselves.

4) The endoscopic biopsy forceps as per Claim 1, characterized in that the shanks are shaped so that, in conditions of rest, the jaws (8a and 8b) are at a preferred and pre-set distance apart and that the angle of the jaws with respect to the respective shanks is such that, when they are closed completely, the edges of the jaws come to be parallel to one another.

5) The endoscopic biopsy forceps as per Claim 1, characterized in that one of the jaws (8a) is provided with a central protuberance (16) and the other (8b) with a bag (15) .

6) The endoscopic biopsy forceps as per Claim 1, characterized in that the slit (14) has its long axis parallel to the long axis of the rigid stretch of the mother cannula.

7) The endoscopic biopsy forceps as per Claim 1, characterized in that the base (9) of the second module is shaped so as to mate perfectly with the plug (12) of the mother cannula and fastened thereon with a screwing mechanism.

8) The endoscopic biopsy forceps as per Claim 1, characterized in that the vector of thrust and retraction acting, through the wire (7), on the cannula (6) in order to close and open the jaws, can be distributed in a more uniform way by providing a second slit on the rigid terminal stretch of the mother cannula opposed to the first slit and getting to pass through it a second steel wire that is fixed to the outer sleeve that carries out constriction on the shanks.

9) The endoscopic biopsy forceps as per Claim 1, characterized in that in the presence of screwing means, the base (9) of the second module, on the side of the jaws, has at the centre a groove where the tip of a device that enables rotation of the second module and release thereof from the first can fit.

10) The endoscopic biopsy forceps as per Claim 1, characterized in that the diameter of the plug (12) of the mother cannula (6) does not exceed the external diameter of the cannula itself.