WO2007014904A1

WO2007014904A1 - Automatic biopsy gun

Info

Publication number: WO2007014904A1
Application number: PCT/EP2006/064755
Authority: WO
Inventors: Giorgio Calanca; Nicola Baroni; Davide Sacchetti; Nicola Vezzani
Original assignee: Medax S.R.L.
Priority date: 2005-07-29
Filing date: 2006-07-27
Publication date: 2007-02-08
Also published as: ZA200800406B; ITMO20050198A1; BRPI0614569A2; MX2008001331A; EP1909634A1

Abstract

An automatic biopsy gun (1), comprising a box-like body (2), provided with a rear end (3) and an opposite front end (4), in which there is an opening (5) for the passage of a needle (6) provided with a cannula (7)and a stylet (8) which is associated so that it can slide axially with the cannula, a first slide (9) with which the cannula (7) can be associated rigidly and which is accommodated so that it can slide axially within the body (2) in contrast with first elastic pusher means (10) between a forward configuration with respect to the front end, in which the first elastic means (10) are extended, and a retracted configuration with respect to the front end (4), in which the first elastic means (10) are compressed, a second slide (11), with which the stylet (8) is rigidly associable and which is accommodated so that it can slide axially within the body (2) in contrast with second elastic pusher means (12) between a forward configuration with respect to the front end (4), in which the second elastic means (12) are extended, and a retracted configuration with respect to the front end (4), in which the second elastic means (12) are compressed, means (16) for actuating the first and second slides (9, 11) from the respective forward configurations to the respective retracted configurations, means (21, 22) for locking temporarily the first and second slides in the respective retracted configurations, and means (24) for disengaging the locking means, which can be actuated from the outside of the body; the actuation means comprise first grip means (16) associated with the first slide (9) and second grip means (17) associated with the second slide (11), both being formed proximate to the rear end and being actuatable for the sliding respectively of the first slide (9) and of the second slide (11) from the forward configuration to the retracted configuration.

Description

AUTOMATIC BIOPSY GUN

Technical Field

The present invention relates to an automatic biopsy gun. Background Art It is known to use automatic biopsy guns in the field of medical procedures for diagnosis, particularly with reference to biopsies for taking a sample of soft tissue from the body of a patient.

Known automatic guns include single-use automatic guns and automatic guns that can be reused for a plurality of successive sampling operations and use single-use biopsy needles.

A first known type of reusable automatic gun generally comprises a body with which it is possible to associate detachably a single-use needle and which has a substantially elongated shape adapted to allow grip on the part of a physician or health worker to perform the biopsy. The body further comprises a first axial end, which is distal with respect to the physician/health worker who holds the gun and from which a portion of the single-use needle protrudes which can be inserted within the body of the patient. The axial end that lies opposite the distal one is termed proximal with reference to the physician/health worker. The needle comprises in general a cannula, which has an end adapted to be inserted in the body of a patient and an opposite end provided with a first element for connection to a first slide which is accommodated slidingly within the body. A stylet is accommodated so that it can slide axially within the cannula and has a pointed end provided with a hollow for collecting a sample of tissue and an opposite end provided with a second element for connection to a second slide accommodated slidingly within the body.

The first and second slides can slide in contrast with respective springs between a forward configuration and a retracted configuration with respect to the distal end. In the transition from the forward configuration to the retracted configuration, the slides slide parallel to the longitudinal axis of the body and toward the proximal end, loading the respective springs.

The automatic gun further comprises a first button and a second button, which are formed on the lateral surface of the body of the gun and can slide along the longitudinal direction of the body from the distal end toward the proximal end for the transition of the first and second slides respectively from the forward configuration to the retracted configuration.

The placement of the slides in the respective retracted configurations is performed by the physician/health worker by pulling with a finger on the first button and then on the second button. The needle is then inserted partially in the body of the patient, positioning the end of the cannula that lies outside the body proximate to the region of tissue at which the sample is to be taken.

Pressure applied by the physician/health worker on the second button and along its direction of sliding toward the distal end allows the release of the slides, with sequential sliding of the first and second slides from the retracted configuration to the forward configuration by way of the action of the respective springs.

This causes the protrusion of the withdrawal end of the stylet from the end of the cannula that is inserted in the body of the patient, placing a portion of soft tissue within the collection notch, and the subsequent sliding of the cannula on the withdrawal end, cutting off said portion of tissue and retaining it inside the needle, which is removed from the body of the patient.

These known automatic guns are not free from drawbacks, including the fact that the placement of the buttons on the side wall of the gun entails grip with one finger of the hand of the physician/health worker, making it difficult to perform the pulling action to position the slides from the forward position to the retracted position.

Further, the buttons must be pulled by the physician/health worker by using a single finger, requiring a substantial effort to load the springs that act on the slides. A second known type of automatic biopsy gun comprises a lever for loading a single central shaft, which is accommodated so that it can slide within the body and is associated with the slides.

In this case, the physician or health worker acts on the lever to slide the slides to the respective retracted configurations, loading the respective springs.

However, even this known automatic gun is not free from drawbacks. The presence of a single shaft to load both the spring that acts on the first slide and the spring that acts on the second slide in fact causes the effort required during the loading procedure to be anything but negligible.

Further, the central arrangement of the shaft and of the springs that act on the slides causes the internal compartment of the body to be difficult to access for cleaning procedures generally performed between two successive biopsies. Disclosure of the Invention

The aim of the present invention is to eliminate the above-mentioned drawbacks of the background art, by providing an automatic biopsy gun that is easy to use and ensures a loading procedure that is simple to perform.

Within this aim, an object of the present invention is to facilitate the operations for replacing the single-use needle and facilitate the operations for internal cleaning of the gun.

Another object of the present invention is to provide an automatic biopsy gun which is simple, relatively easy to provide in practice, safe in use, effective in operation, and has a relatively low cost. This aim and these and other objects that will become better apparent hereinafter are achieved by the present automatic biopsy gun, which comprises a box-like body, provided with a rear end and an opposite front end, in which there is an opening for the passage of a needle provided with a cannula and a stylet which is associated so that it can slide axially with the cannula, a first slide with which the cannula can be associated rigidly and which is accommodated so that it can slide axially within the body in contrast with first elastic pusher means between a forward configuration with respect to the front end, in which the first elastic means are extended, and a retracted configuration with respect to the front end, in which the first elastic means are compressed, a second slide, with which the stylet is rigidly associable and which is accommodated so that it can slide axially within the body in contrast with second elastic pusher means between a forward configuration with respect to the front end, in which the second elastic means are extended, and a retracted configuration with respect to the front end, in which the second elastic means are compressed, means for actuating the first and second slides from the respective forward configurations to the respective retracted configurations, means for locking temporarily the first and second slides in the respective retracted configurations, and means for disengaging the locking means, which can be actuated from the outside of the body, characterized in that the actuation means comprise first grip means, associated with the first slide, and second grip means, associated with the second slide, both being formed proximate to the rear end and being actuatable for the sliding respectively of the first slide and of the second slide from the forward configuration to the retracted configuration. Brief Description of the Drawings

Further characteristics and advantages of the present invention will become better apparent from the following detailed description of a preferred but not exclusive embodiment of an automatic biopsy gun, illustrated by way of non-limiting example in the accompanying drawings, wherein:

Figure 1 is a plan view of the gun according to the invention, with both slides in the forward configuration and with the cover removed;

Figure 2 is a plan view of the gun according to the invention, with the first slide in the retracted configuration and with the cover removed; Figure 3 is a plan view of the gun according to the invention, with the first and second slides in the retracted configuration and with the cover removed;

Figure 4 is a plan view, similar to Figure 3, with a single-use needle inserted; Figure 5 is a side view of the gun according to the invention, with a single-use needle inserted and with the cover closed, the first slide being in the retracted configuration and the second slide being in the forward configuration;

Figure 6 is a partially sectional front view of Figure 5; Figure 7 is a partial sectional side view of an alternative embodiment of the gun according to the invention, with the first and second slides in the retracted position and with the single-use needle inserted;

Figure 8 is a plan view of the gun of Figure 7, with the first slide in the retracted position and the second slide in the forward position. Ways of carrying out the Invention

With reference to the figures, the reference numeral 1 generally designates a biopsy gun, particularly but not exclusively with reference to a reusable biopsy gun.

The gun 1 comprises a substantially elongated box-like body 2, which has a rear end 3 and an opposite front end 4 in which there is an opening 5 for the passage of a biopsy needle 6 of the single-use type.

The needle 6 comprises a cannula 7 and a stylet 8, which is accommodated so that it can slide axially within the cannula 7.

The cannula 7 has an end adapted to be inserted in the body of a patient and an opposite end provided with a first handle 7a.

The stylet 8 has a pointed end, provided with a notch which is adapted to collect a tissue sample, and an opposite end provided with a second handle 8a.

The gun 1 further comprises a first slide 9, with which the cannula 7 is rigidly associated; the slide is accommodated so that it can slide axially within the body 2, in contrast with first elastic pusher means 10, between a forward configuration with respect to the front end 4, in which the first elastic means 10 are extended, and a retracted configuration with respect to the front end 4, in which the first elastic means 10 are compressed. A second slide 11, with which the stylet 8 is rigidly associated, is accommodated so that it can slide axially within the body 2, in contrast with second elastic pusher means 12, between a forward configuration with respect to the front end 4, in which the second elastic means 12 are extended, and a retracted configuration with respect to the front end 4, in which the second elastic means 12 are compressed.

The needle 6 can be inserted within the body 2 after opening a cover 2a, which is pivoted proximate to the rear end 3.

Advantageously, the first slide 9 and the second slide 11 comprise means for detachably coupling the cannula 7 and the stylet 8 respectively. In the illustrated embodiment, the first slide 9 is provided with a receptacle 9a for accommodating the first handle 7a, while the second slide 11 is provided with a respective receptacle 1 Ia for accommodating the second handle 8a.

The body 2 comprises a front compartment for accommodating the first slide 9, which is delimited by the side walls of the body 2, by the front end 4 and by an intermediate wall 13, and a rear compartment for accommodating the second slide 11, which is delimited by the side walls of the body 2, by the intermediate wall 13 and by the rear end 3.

Each one of the first and second elastic means 10 and 12 comprises at least one pusher spring 14, which is supported by a guiding shaft 15 and acts respectively between the intermediate wall 13 and the first slide 9 and between a wall formed at the rear end 3 and the second slide 11.

In a preferred embodiment, the first and second elastic means 10 and 12 comprise respectively a pair of pusher springs 14 of the helical type, supported by the respective guiding shafts 15, which are substantially parallel to the longitudinal axis of the body 2 and are fixed, at one axial end, to the rear end 3 and, at the opposite axial end, to the front end 4.

Further, the guiding shafts 15 are mutually spaced and arranged proximate to two opposite side walls of the body 2.

The gun 1 further comprises means for actuating the first and second slides 9 and 11 from the respective forward configurations to the respective retracted configurations.

The actuation means of the first slide 9 comprise first grip means 16, which protrude from the rear end 3 and with which the grip end, which protrudes from the rear end 3, of a first stem 18 is rigidly associated, said first stem being in turn associated with the first slide 9.

The actuation means of the second slide 11 comprise second grip means 17, which protrude from the rear end 3 and with which the grip end, which protrudes from the rear end 3, of a second stem 19 is rigidly associated, said second stem being in turn associated with the second slide 11.

Advantageously, the first and second grip means 16 and 17 are constituted respectively by a first grip handle and a second grip handle, which can be gripped by a physician or health worker, so as to extract respectively the first stem 18 and the second stem 19 and thus move the first slide 9 and the second slide 11 from the respective forward configuration to the respective retracted configuration.

Further, the second grip means 17 comprise means for moving the first grip means 16 which are adapted for the simultaneous sliding of the first and second slides 9 and 11 toward the respective retracted configurations.

In the illustrated embodiment, the movement means comprise a protrusion 17a, which is formed on the second grip means 17 and can mate with a corresponding abutment 16a formed on the first grip means 16.

The first stem 18 and the second stem 19 are substantially parallel to the guiding shafts 15. A respective return spring 20 is interposed between the end of the first stem 18 that lies opposite the first grip means 16 and the first slide 9 and between the end of the second stem 19 that lies opposite the second grip means 17 and the second slide 11; the springs act in contrast with the movement of the first and second slides 9 and 11 from the respective forward configurations to the respective retracted configurations.

The first stem 18 can slide through a respective through hole in the intermediate wall 13.

The gun 1 comprises means for locking temporarily the first slide 9 and the second slide 11 in the respective retracted configurations and means for disengaging said locking means, which can be actuated manually from the outside of the body 2.

In particular, the locking means comprise at least one first element 21 for retaining the first slide 9 and at least one second element 22 for retaining the second slide 11, which can slide toward and away from the first and second slides 9 and 11, respectively, in contrast with respective elastic locking means 23 and at right angles to the sliding direction of the first and second slides 9 and 11.

The disengagement means comprise at least one actuation button 24, which is arranged at the front end 4 and/or at the rear end 3.

Advantageously, the disengagement means comprise a firing rod 25, which is associated so that it can slide axially with respect to the body 2 and is provided with axial ends which protrude from the rear end 3 and from the front end 4 so as to form two buttons 24. The rod 25 comprises contoured surfaces 26 for contact with the first retention element 21 and with the second retention element 22, which are adapted to convert the sliding motion of the rod 25 into the motion of the first and second retention elements 21 and 22 respectively away from the first slide 9 and the second slide 11. The first and second retention elements 21 and 22 comprise respective supporting surfaces 21a and 22a for the corresponding contoured surfaces 26 and two retention teeth 27, which can engage in at least one complementary slot 28 formed respectively on the first slide 9 and on the second slide 11. The elastic locking means 23 comprise two springs, which act by compression to move the first and second retention elements 21 and 22 closer to the first and second slides 9 and 11, engaging the teeth 27 within the corresponding slot 28 and producing contact between the supporting surfaces 21a and 22a and the respective contoured surfaces 26. Each contoured surface 26 comprises at least two inclined portions, which are adapted to engage, during the sliding of the rod 25, on the supporting surfaces 21a and 22a in order to move the retention elements 21 and 22 respectively away from the first slide 9 and the second slide 11.

In particular, the contoured surface 26, which is adapted to make contact with the first retention element 21, comprises at least one portion which is substantially parallel to the sliding direction of the rod 25 and is sized appropriately in order to move the first retention element 21 away from the first slide 9 after the movement of the second retention element 22 away from the second slide 11. The gun 1 comprises means for stopping temporarily the sliding of the rod 25 in the respective retracted configurations of the first slide 9 and of the second slide 11.

The temporary stop means comprise a pin 29, which is associated slidingly with the body 2, inside the front compartment, is substantially perpendicular to the rod 25 and is inserted so that it can slide within a slot 25 a formed therein.

The pin 29 comprises at least one expansion 29a, which can be inserted in a substantially circular central wider portion of the slot 25a in order to stop the sliding of the rod 25, the diameter of said wider portion being substantially equal to the diameter of the expansion 29a. The pin 29 has an end that protrudes from the body 2 and is provided with a handle 30, and a spring 31 acts between its opposite end and an internal surface of the body 2 and is adapted to position the expansion 29a at the wider portion of the slot 25 a. A flat spring 32 is fixed to the body 2 inside the front compartment and is adapted to engage in a recess 33 formed in the pin 29 in order to lock the sliding of the pin 29 in a configuration in which the expansion 29a is disengaged from the wider portion of the slot 25 a.

Further, the flat spring 32 is adapted to make contact with the first slide 9 in the transition between the retracted configuration and the forward configuration for its disengagement from the recess 33.

Means for adjusting the advancement of the second slide 11 are further provided on the front end 4 of the body 2.

The per se known adjustment means consist of an actuation knob 34, which is pivoted to the front end 4, with a pivoting axis which is substantially parallel to the guiding shafts 15.

The actuation knob 34 is connected rigidly to at least one abutment element 35, which is fixed rotatably to the intermediate wall 13, by means of a bar 36. In a particular embodiment, there are two abutment elements 35 respectively for the first and second slides 9 and 11; both are rigidly coupled to the bar 36 and are associated so that they can rotate respectively with the intermediate wall 13 and with the front end 4.

By turning the actuation knob 34, the abutment elements 35 rotate rigidly with it, moving to a configuration of interference with the first slide 9 and the second slide 11, changing their respective strokes.

Figures 7 and 8 illustrate an alternative embodiment of the gun 1, in which the disengagement mechanism of the first slide 9 and of the second slide 11 is optimized so that the delay of the advancement of the slide 9 with respect to the slide 11 is assured and repeatable whenever the button 24 is pressed from the rear end 3 and from the front end 4 of the gun 1.

In this embodiment, the first retention element 21 of the first slide 9 is not actuated directly by the rod 25 but is actuated by the advancement motion of the second slide 11. The retention element 21 comprises a retention lever 37 for the first slide 9, which is pivoted so that it can oscillate with respect to an axis which is substantially perpendicular to the guiding shafts 15 and on a plane which is substantially parallel to the plane formed by the bottom of the body 2.

The retention lever 37 has a contoured end 38, which engages within the slot 28 of the first slide 9.

A first elastic return element 39, for example a helical spring, is interposed between the retention lever 37 and the bottom of the box-like body 2 and pushes the retention lever 37 toward the first slide 9, so as to mate with the slot 28. A disengagement means is pivoted to the second slide 11 and is adapted to interact with the retention lever 37 in the advancement movement of the second slide 11.

The disengagement means is formed by a contoured rod 40, the front end of which, during the advancement motion of the second slide 11, is adapted to affect the retention lever 37, pushing it toward the bottom of the body 2 in contrast with the first elastic return element 39, so as to disengage the contoured end 38 from the slot 28.

Advantageously, the contoured rod 40 is pivoted, proximate to its rear end, to the second slide 11 so that it can oscillate with respect to an axis which is substantially perpendicular to the plane formed by the bottom of the body 2.

A second elastic return element 41 acts on the rear end of the contoured rod 40 and keeps it substantially parallel to the guiding shafts 15.

A first fixed pivot 42 is further provided on the intermediate wall 13 and is adapted to divert the contoured rod 40 in the advancement stroke of the second slide 11 in contrast with the action of the second elastic return element 41 after its front end has engaged the retention lever 37, disengaging it from the first slide 9.

A second pivot 43 is arranged to the side of the contoured rod 40 on the opposite side with respect to the second elastic return element 41, so as to constitute an angular stroke limiting point for the contoured rod 40.

The operation of the present invention is as follows.

Before using the gun 1, the first and second slides 9 and 11 are in the respective forward configuration and the expansion 29a of the pin 29 is inserted in the expanded portion of the slot 25a, locking the sliding of the rod 25.

A health worker, by pulling the first grip means 16, moves the first slide 9 from the forward configuration to the retracted configuration, loading the first elastic means 10. Subsequently, by pulling the second grip means 17, the second slide

11 is moved from the forward configuration to the retracted configuration.

As an alternative, by performing a single pulling action on the second grip means 17 first, thanks to the interference between the protrusion 17a and the abutment 16a, it is possible to make both slides slide simultaneously in the respective retracted configuration.

Once the first and second slides 9 and 11 reach the retracted configuration, they are retained respectively by the first and second retention elements 21 and 22, while the first and second pins 18 and 19 are moved by the respective return springs 20 to the forward configuration. The cover 2a is opened and the needle 6 is inserted within the body 2, generally when the slides are in their respective retracted configuration, anchoring the first handle 7a of the cannula 7 in the seat 9a of the slide 9 and the second handle 8a of the stylet 8 in the respective seat 11a of the second slide 11. The health worker then inserts the needle portion 6 that protrudes from the gun 1 into the body of the patient, arranging it proximate to the region of tissue to be sampled.

Pressure applied to the handle 30 produces the disengagement of the expansion 29a from the slot 25a, with insertion of the flat spring 32 within the hollow 33 and consequent locking of the pin 29.

Subsequently, pressure on one of the buttons 24 produces the sliding of the rod 25, with sequential spacing initially of the second retention element 22, then of the first retention element 21, respectively, from the second slide 11 and from the first slide 9. The sequential disengagement of the second retention element 22 and, with a preset delay, of the first retention element 21 releases in succession the second slide 11 and the first slide 9, which thus slide from the respective retracted configuration to the advanced configuration.

In this manner, the stylet 8 slides forward with respect to the cannula 7, so that its forward end protrudes from said cannula to accommodate a portion of the tissue to be sampled within the collection notch; the cannula 7 then advances on the stylet 8, cutting off the sample of tissue and retaining it within the notch of the stylet 8.

The first slide 9, in this forward configuration, acts on the flat spring 32, moving it away from the recess 33; the pin 29 thus slides toward the outside of the body 2 by way of the action of the spring 31, and the expansion 29a is arranged at the wider portion of the slot 25a.

In the embodiment shown in Figures 7 and 8, by applying pressure to the button 24 the second retention element 22 of the second slide 11 is disengaged first; the second slide 11 thus advances until it abuts against the intermediate wall 13.

During the advancement stroke of the second slide 11, the stylet 8 slides with respect to the cannula 7, from which it protrudes in order to collect within the collection notch a portion of tissue to be sampled. During said advancement stroke of the second slide 11, the contoured rod 40 engages the retention lever 37, disengaging its contoured end 38 from the slot 28; the first slide 9 can thus slide freely toward the front end 4 of the body 2.

The advancement of the first slide 9 produces the sliding of the cannula 7 on the stylet 8; the sample of tissue collected in the notch of the stylet 8 is thus cut off and retained within the needle 6.

When the second slide 11 reaches the end of its stroke, the contoured rod 40 is diverted by the first pivot 42, in contrast with the action of the second elastic return element 41, so as to not interfere with the return motion of the retention lever 37 produced by the thrust of the first elastic return element 39.

After the first and second slides 9 and 11 have reached the end of the advancement stroke, the lack of interference between the contoured rod 40, diverted by the first pivot 42, and the retention lever 37 allows to return the first slide 9 to the retracted configuration, while the second slide 11 remains in the forward configuration.

In this configuration, the cannula 7 retracts toward the inside of the body 2, sliding with respect to the stylet 8, so that the health worker can remove the tissue sample collected in the notch of the stylet 8. In both embodiments of the gun 1 it is possible to modify or reduce the advancement stroke of the first and second slides 9 and 11, so as to collect a smaller quantity of tissue, by acting on the respective adjustment means. In particular, by turning the actuation knob 34, the abutment elements 35, which rotate rigidly therewith, move from a configuration of noninterference to a configuration of interference with the stroke of the first slide 9 and the second slide 11. The abutment elements 35 thus act as front stroke limiters as an alternative to the intermediate wall 13 and the front end 4.

In practice it has been found that the described invention achieves the proposed aim and objects. In particular, the fact is stressed that positioning the first and second grip means at the rear axial end of the body of the gun according to the invention facilitates grip on the part of the operator and the operation for loading the two slides. Further, the spaced arrangement of the guiding shafts of the first and second elastic means frees the central space of the internal compartments, allowing easier cleaning of the gun.

Further, the presence of the firing rod allows to release the stroke of the slides from the respective retracted configuration to the respective forward configuration by pressing the rear button or by pressing the front button.

Moreover, the described gun is of the reusable type and allows the use of single-use needles commonly used to perform biopsies manually.

The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims.

All the details may further be replaced with other technically equivalent elements.

In practice, the materials used, as well as the contingent shapes and dimensions, may be any according to requirements without thereby abandoning the scope of the protection of the appended claims.

The disclosures in Italian Patent Application No. MO2005A000198 from which this application claims priority are incorporated herein by reference.

Claims

1. An automatic biopsy gun, comprising a box-like body, provided with a rear end and an opposite front end, in which there is an opening for the passage of a needle provided with a cannula and a stylet which is associated so that it can slide axially with said cannula, a first slide with which said cannula can be associated rigidly and which is accommodated so that it can slide axially within said body in contrast with first elastic pusher means between a forward configuration with respect to said front end, in which said first elastic means are extended, and a retracted configuration with respect to said front end, in which said first elastic means are compressed, a second slide, with which said stylet is rigidly associable and which is accommodated so that it can slide axially within said body in contrast with second elastic pusher means between a forward configuration with respect to said front end, in which said second elastic means are extended, and a retracted configuration with respect to said front end, in which said second elastic means are compressed, means for actuating said first and second slides from said respective forward configurations to said respective retracted configurations, means for locking temporarily said first and second slides in said respective retracted configurations, and means for disengaging said locking means, which can be actuated from the outside of said body, characterized in that said actuation means comprise first grip means, associated with said first slide, and second grip means, associated with said second slide, both being formed proximate to said rear end and being actuatable for the sliding respectively of said first slide and of said second slide from said forward configuration to said retracted configuration.

2. The gun according to claim 1, characterized in that said actuation means comprise a first stem for the actuation of said first slide, which is associated slidingly with said body and has a grip end which protrudes from said rear end and is provided with said first grip means, a second stem for the actuation of said second slide, which is associated slidingly with said body and has a grip end which protrudes from said rear end and is provided with said second grip means.

3. The gun according to one or more of the preceding claims, characterized in that said first grip means and said second grip means comprise respectively a first grip handle and a second grip handle.

4. The gun according to claim 3, characterized in that said second handle comprises means for moving said first handle.

5. The gun according to claim 4, characterized in that said movement means comprise at least one protrusion, which is formed on said second handle and can be coupled to at least one corresponding abutment on said first handle.

6. The gun according to one or more of the preceding claims, characterized in that said body is substantially elongated and comprises a front compartment for accommodating said first slide, which is formed between said front end and an intermediate wall, and a rear compartment for accommodating said second slide, which is formed between said intermediate wall and said rear end.

7. The gun according to one or more of the preceding claims, characterized in that said first elastic means comprise at least one pusher spring, which is supported by a guiding shaft which is fixed to said body, said pusher spring acting between said first slide and said intermediate wall.

8. The gun according to one or more of the preceding claims, characterized in that said second elastic means comprise at least one pusher spring, which is supported by a guiding shaft which is fixed to said body, said pusher spring acting between said rear end and said second slide.

9. The gun according to claims 7 and 8, characterized in that each one of said first elastic means and said second elastic means comprises at least one pair of said pusher springs supported by respective guiding shafts, said shafts being substantially parallel to the longitudinal axis of said body and being mutually spaced.

10. The gun according to one or more of the preceding claims, characterized in that said locking means comprise at least one first element for retaining said first slide and at least one second element for retaining said second slide, which can slide toward and away from said first slide and said second slide, respectively.

11. The gun according to claim 10, characterized in that said first and second retention elements can slide along a direction which is substantially perpendicular to the sliding direction of said first and second slides.

12. The gun according to claim 10 or 11, characterized in that said first retention element comprises a retention lever, which is associated with said intermediate wall so that it oscillates about an axis which is substantially parallel to the bottom of said body and is perpendicular to the advancement direction of said first and second slides.

13. The gun according to one or more of claims 10 to 12, characterized in that said locking means comprise elastic means for contrasting the spacing of said first and second retention elements from said first and second slides.

14. The gun according to one or more of claims 10 to 13, characterized in that said first and second retention elements comprise at least one stop tooth, which can be engaged in at least one complementary slot formed respectively on said first and second slides.

15. The gun according to one or more of the preceding claims, characterized in that said disengagement means comprise at least one button arranged at at least one of said front and rear ends.

16. The gun according to claim 15, characterized in that said disengagement means comprise two of said buttons arranged respectively proximate said front and rear ends.

17. The gun according to claim 15 or 16, characterized in that said disengagement means comprise a firing rod, which is associated with said body so that it can slide axially and is provided with axial ends which protrude from said front and rear ends so as to form said buttons and comprises contoured surfaces for contact with said first and second retention elements adapted to convert the sliding motion of said rod into the motion of said first and second retention elements away from said slides.

18. The gun according to claim 17, characterized in that said contoured surfaces comprise at least two inclined portions which are in contact with respective supporting surfaces of said first and second retention elements by way of the action of said locking means.

19. The gun according to one or more of claims 12 to 18, characterized in that it comprises at least one means for disengaging said retention lever from said first slide which is associated with said second slide, said disengagement element being adapted to interact with said retention lever during the advancement of said second slide from said retracted configuration to said forward configuration.

20. The gun according to claim 19, characterized in that said disengagement means comprises a contoured rod associated with said second slide so that it can oscillate about an axis which is substantially perpendicular to the bottom of said body.

21. The gun according to claim 20, characterized in that it comprises at least one second elastic return element, which is arranged on said second slide and acts on said contoured rod, said contoured rod being kept temporarily in a position which is substantially parallel to said guiding shaft.

22. The gun according to claim 21, characterized in that said intermediate wall comprises a first fixed pivot, which is adapted, during the advancement stroke of said second slide, to divert said contoured rod in contrast with said second elastic return element.

23. The gun according to one or more of the preceding claims, characterized in that it comprises means for stopping temporarily the sliding of said firing rod, said first and second slides being in the respective retracted configuration.

24. The gun according to claim 23, characterized in that said temporary stop means comprise a pin which is slidingly associated with said body, is substantially perpendicular to said firing rod and comprises at least one expansion which can be inserted in at least one wider portion of a slot formed in said firing rod.

25. The gun according to one or more of the preceding claims, characterized in that said first slide comprises means for detachably coupling said cannula and said second slide comprises means for detachably coupling said stylet.

26. The gun according to claim 25, characterized in that said means for the detachable coupling of said cannula comprise a seat for accommodating a first handle of said needle which is fixed to a grip end of said cannula and in that said means for the detachable coupling of said stylet comprise a seat for accommodating a second handle of said needle which is fixed to a grip end of said stylet.