WO2007009901A1

WO2007009901A1 - Needle for soft tissue biopsy

Info

Publication number: WO2007009901A1
Application number: PCT/EP2006/064065
Authority: WO
Inventors: Giorgio Calanca; Nicola Baroni; Davide Sacchetti; Nicola Vezzani
Original assignee: Medax S.R.L.
Priority date: 2005-07-15
Filing date: 2006-07-10
Publication date: 2007-01-25
Also published as: ITMO20050182A1; EP1903945A1; MX2008000667A; BRPI0613061A2

Abstract

A semiautomatic needle (1) for soft tissue biopsy, comprising a body (2) and a slider (3) which can slide with respect to the body by way of the action of elastic means, means for actuating the sliding of the slider, a stylet (4) which is slidingly associated with the body (2), which is accommodated in a through hole formed in the slider (3) and has a grip end (4a) and an opposite end (4b) for removing a tissue sample, a cannula (6) inside which the stylet (4) is accommodated so that it can slide axially and which has a proximal end (6a) which is detachably associated with the slider (3) and a distal end (6b) which is adapted to be inserted in the body of the patient, means for temporary retention of the proximal end of the cannula with the slider (3) which comprise a locking ring (7), means (11) for temporarily locking the relative rotation between the cannula and the slider being provided.

Description

NEEDLE FOR SOFT TISSUE BIOPSY

Technical Field

The present invention relates to a needle for soft tissue biopsy. Background Art In the field of medical diagnostic procedures, with particular reference to biopsies, it is known to use semiautomatic needles that allow to remove from the body of a patient soft organic issues to be analyzed.

Among the various types of semiautomatic biopsy needles, the use of a so-called guillotine needle has been known for some time. This needle is constituted by a body provided with a handpiece and a slider which can slide with respect to the body by way of the action of a spring.

A stylet is associated slidingly with the body and is inserted in a through hole formed in the slider. The stylet has an end provided with a grip knob and an opposite end which is pointed and provided with a notch for collecting a sample of tissue taken from the body of a patient.

A cannula is fixed to the slider at an axial end thereof, which is generally termed proximal end with respect to the physician or health operator who performs the biopsy. The cannula slidingly accommodates the stylet, and its end that lies opposite the proximal end, known as distal end, is sharp and is adapted to be inserted in the body of a patient.

The method of use of such needle provides for a first step in which the slider is moved to, and locked in, a spring loading position.

The physician or health operator then performs the percutaneous penetration of at least one portion of the cannula into the body of a patient, after local anesthesia and with constant sonogram monitoring of the patient, placing the distal end of the cannula in the vicinity of the region of soft tissue to be sampled.

Once the intended placement of the cannula has been achieved, a pressure of the physician/health operator on the grip knob causes the pointed end to protrude together with the collection notch of the stylet from the distal end of the cannula, cutting part of the tissue, which is thus arranged at the collection notch.

A further pressure on the grip knob releases the slider, which as a consequence of the action of the spring produces the advancement of the cannula until the stylet is covered completely, consequently cutting and retaining the portion of tissue arranged inside the collection notch.

At this point the needle can be removed from the body of the patient. If it is necessary to collect a plurality of samples in a same soft tissue region, it is known to use so-called coaxial needles in order to avoid successive extractions and insertions of biopsy needles.

Coaxial needles are constituted by a tubular element, whose inside diameter is larger than the diameter of the cannula of the semiautomatic needle in which a stylet for blocking the internal opening is inserted. The physician/health operator inserts the coaxial needle in the body of the patient up to the soft tissue region to be sampled, removes the blocking stylet, and inserts the cannula of the semiautomatic needle inside the tubular element. In this manner, successive samples of tissue can be taken while keeping the coaxial needle in position, with an approach which is relatively less invasive for the patient.

These known biopsy needles are not free from drawbacks, which include the fact that performing a plurality of biopsies requires the further use of the coaxial needle, which entails higher supply costs for the health organization and complicates the operations performed by health operators. Further, the larger diameter of the coaxial needle with respect to the diameter of the cannula of the semiautomatic needle makes the procedure more invasive for the patient.

As an alternative to the use of coaxial needles, semiautomatic needles are known in which the cannula is detachably associated with the slider. In this manner, once the tissue sample has been collected, the cannula is disengaged from the slider and the stylet is removed.

The cannula remains inserted in the body of the patient with its distal end, which is located proximate to the soft tissue region to be sampled, and for subsequent samplings it is sufficient to insert the stylet again. Semiautomatic needles are also known which have a removable cannula in which the proximal end of the cannula is mated with the slider with a threaded coupling of the Luer-Lok type and in which said cannula is disengaged by turning it with respect to the slider.

These needles are not free from drawbacks: the procedure for disengaging the cannula from the slider requires a rotation thereof within the body of the patient, with a high risk of internal lacerations and of damage to the tissue involved in subsequent samplings.

Semiautomatic needles with a removable cannula are also known in which the disengagement of the cannula from the body occurs by acting on actuators such as buttons or levers. However, even these needles have drawbacks.

During the procedure for taking the tissue sample, unintended disengagement of the cannula from the body of the needle may occur, particularly due to accidental impacts by the physician/operator with said buttons or levers or as a consequence of stresses on the cannula caused by its advancement for cutting the tissue sample. Disclosure of the Invention

The aim of the present invention is to eliminate the drawbacks mentioned above of the background art, by providing a semiautomatic needle that ensures a stable and safe engagement of the cannula during the execution of the biopsy.

An object of the present invention is to ensure a disengagement of the cannula from the slider which is simple and easy to perform, does not injure the patient and is not additionally invasive for the patient. Within this aim, another object of the present invention is to provide a needle 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 semiautomatic needle for soft tissue biopsy, which comprises a body and a slider which can slide with respect to the body by way of the action of elastic means, means for actuating the sliding of the slider, a stylet which is slidingly associated with the body, which is accommodated in a through hole formed in the slider and has a grip end and an opposite end for removing a tissue sample, a cannula inside which the stylet is accommodated so that it can slide axially and which has a proximal end which is detachably associated with the slider and a distal end which is adapted to be inserted in the body of the patient, means for temporary retention of the proximal end of the cannula with the slider being provided, characterized in that the temporary retention means comprise a locking ring, means for temporarily locking the relative rotation between the cannula and the slider being provided.

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 a semiautomatic needle for soft tissue biopsy, illustrated by way of non-limiting example in the accompanying drawings, wherein:

Figure 1 is a plan view of the biopsy needle according to the invention and of the respective cannula; Figure 2 is a plan view of the biopsy needle according to the invention, in which the cannula is partially inserted in the stylet;

Figure 3 is a plan view of the biopsy needle according to the invention, in which the cannula is associated with the body of the needle;

Figure 4 is a view of a detail of the biopsy needle according to the invention. Ways of carrying out the Invention

With reference to the figures, the reference numeral 1 generally designates a semiautomatic needle for soft tissue biopsy.

The needle 1 comprises a body 2 with which a slider 3 is associated which can slide, by way of the action of elastic means, from a position which is retracted with respect to the body 2 to a position which is extended toward the outside of the body 2, or vice versa, means being provided for actuating the sliding of the slider 3, said means not being shown in detail in the figures. A stylet 4 is associated slidingly with respect to the body 2 and is accommodated in a through hole formed in the slider 3. The stylet 4 has a grip end 4a, which is provided with a knob 5 and is arranged opposite an end 4b for removing a tissue sample.

In particular, the knob 5 is associated so that it can slide with respect to the slider 3 and is adapted to be gripped by an operator or physician. Traction is applied to the knob 5 in order to position the slider 3 in the retracted position, loading the elastic means.

Subsequent pressure by a physician/health operator on the knob 5 produces the sliding of a portion of the stylet 4 with respect to the slider 3 and the subsequent actuation of the actuation means, with release of the elastic means which act for the sliding of the slider 3 from the retracted position to the extended position.

The sampling end 4b is substantially pointed and is provided with a notch 4c for collecting the tissue sample. A cannula 6 is adapted to accommodate internally the stylet 4 so that it can slide axially with respect to the cannula, and has a proximal end 6a, which is associated detachably with the slider 3 by way of temporary retention means.

The term "proximal" is used to reference the position of such end with respect to the physician or health operator who grips the needle 1 in order to perform the biopsy.

A distal end 6b of the cannula 6 which lies opposite the proximal end 6a is sharp and is adapted to be inserted in the body of a patient in order to position it proximate to the region of soft tissue to be sampled. Further, the sampling end 4b is adapted to exit from the distal end 6b for cutting and subsequently retaining a sample of soft tissue inside the collection notch 4c.

The retention means comprise a locking ring 7, which is associated rotatably with either the slider 3 or the proximal end 6a and is provided with first threaded means 8 for mating with second threaded means 9 formed on the slider 3 or the proximal end 6a, respectively.

With reference to the preferred but not exclusive embodiment of the invention being considered, the locking ring 7 is associated rotatably with the slider 3 and the first threaded means 8 comprise a thread which is arranged inside the ring 7.

The second threaded means 9 comprise an external thread, which is formed on the proximal end 6a.

In particular, the slider 3 comprises a portion which protrudes from the body 2 and is provided with a tab 10 for coupling the cannula 6, which is substantially tubular.

The through hole that accommodates the stylet 4 is formed at the outer end of the coupling tab 10.

Conveniently, the proximal end 6a of the cannula 6 is constituted by a support made of plastic material, which is substantially tubular and comprises at least one portion 6c for the insertion of the coupling tab 10.

The locking ring 7 comprises a substantially cylindrical and hollow element, which is open at its opposite ends and is provided, at one end, with the first threaded means 8 and, at the opposite end, with an annular lip 7a, which is associated rotatably and with play with the slider 3 at a groove 10a formed on the coupling tab 10. The coupling tab 10 further has means for stopping the axial sliding of the locking ring 7 with respect to the slider 3, which comprise an annular collar 10b, which protrudes toward the center on the outer surface of the coupling tab 10, and a shoulder 10c, which is formed by the wall of the protruding portion of the slider 3 from which the coupling tab 10 protrudes.

The groove 10a is delimited by the collar 10b and by the shoulder 10c.

The needle 1 further comprises means for temporarily locking the relative rotation between the cannula 6 and the slider 3, which are formed at the coupling tab 10.

In particular, the means for temporarily locking the rotation comprise a side-fit coupling between the coupling tab 10 and the proximal end 6a of the cannula 6.

The side-fit coupling comprises a longitudinal slot 11, which is formed on the internal surface of the insertion portion 6c and can be coupled to a corresponding longitudinal rib 12, which protrudes from the outer surface of the coupling tab 10.

The operation of the needle according to the present invention is as follows. First of all, the semiautomatic needle 1 for multiple soft tissue biopsies is prepared by a physician or health operator for use by loading the elastic means, positioning the slider 3 (and the cannula 6 connected thereto) in the retracted position with respect to the body 2. Loading occurs by pulling the knob 5 fixed to the stylet 4. At least one portion of the cannula 6 is inserted within the body 2 of a patient, positioning the distal end 6b proximate to the region of soft tissue to be sampled.

A pressure of the physician/health operator on the knob 5 causes the stylet 4 to slide with respect to the slider 3, causing the exit of the protruding end 4b from the distal end 6b and arranging at least one portion of soft tissue inside the collection notch 4c.

A further pressure of the physician/health operator on the knob 5 actuates the actuation means, releasing the slider 3, which slides, by way of the action of the elastic means, from the retracted position to the extended position. This entails the sliding of the distal end 6b of the cannula 6 on the sampling end 4b, cutting the tissue sample arranged inside the collection notch 4c and retaining it within the needle 1.

The physician/health operator turns the locking ring 7 in order to uncouple the first and second threaded means 8 and 9, and during this rotation the coupling between the longitudinal slot 11 and the longitudinal rib 12 couples the proximal end 6a to the coupling tab 10, preventing the rotation of the cannula 6 rigidly with the locking ring 7.

The stylet 4 is then removed from the cannula 6 together with the tissue sample. In order to perform successive biopsies on the same patient and in the vicinity of the same region of soft tissue, the stylet 4 is inserted again within the cannula 6, the longitudinal groove 10a is positioned at the longitudinal rib 12, and the locking ring 7 is turned for mating between the first and second threaded means 8 and 9. In practice it has been found that the described invention achieves the intended aim and objects, and in particular the fact is stressed that fixing the cannula to the slider by means of the locking ring ensures stable and safe coupling of the cannula during the execution of the biopsy.

Further, the disengagement and locking of the cannula with respect to the slider by rotation of the locking ring is simple and easy to perform and the presence of the means for locking the relative rotation between the cannula and the slider prevent unwanted rotations of the cannula inside the body of the patient, avoiding lesions of the tissue and limiting the invasiveness of these disengagement and locking maneuvers. 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. MO2005 AOOO 182 from which this application claims priority are incorporated herein by reference.

Claims

1. A semiautomatic needle for soft tissue biopsy, comprising a body and a slider which can slide with respect to said body by way of the action of elastic means, means for actuating the sliding of said slider, a stylet which is slidingly associated with said body, which is accommodated in a through hole formed in said carriage and has a grip end and an opposite end for removing a tissue sample, a cannula inside which said stylet is accommodated so that it can slide axially and which has a proximal end which is detachably associated with the slider and a distal end which is adapted to be inserted in the body of the patient, means for temporary retention of said proximal end of said cannula with said slider being provided, characterized in that said temporary retention means comprise a locking ring, means for temporarily locking said relative rotation between said cannula and said slider being provided.

2. The needle according to claim 1, characterized in that said locking ring is associated rotatably with either said slider or said proximal end of said cannula and is provided with first threaded coupling means, which correspond to second threaded means formed on said slider or said proximal end of said cannula, respectively.

3. The needle according to claim 1 or 2, characterized in that said locking ring is associated rotatably with said slider and in that said first threaded means comprise a thread arranged inside said locking ring, said second threaded means comprising an external thread formed on the proximal end of said cannula.

4. The needle according to one or more of the preceding claims, characterized in that said locking ring comprises a hollow cylindrical element, which is open at its opposite ends and is provided, at one end, with said first threaded means and, at the opposite end, with an annular lip, which is rotatably associated with said slider, means for stopping the axial sliding of said ring with respect to said slider being provided.

5. The needle according to one or more of the preceding claims, characterized in that said slider comprises a tab for the coupling of said cannula which is adapted to be inserted within said proximal end of said cannula, said means for temporarily locking the relative rotation being formed at said tab.

6. The needle according to one or more of the preceding claims, characterized in that said means for temporarily locking the relative rotation comprise a side-fit coupling between said tab and said proximal end of said cannula.

7. The needle according to one or more of the preceding claims, characterized in that said side-fit coupling comprises a longitudinal slot formed inside said proximal end and a corresponding longitudinal rib which protrudes from the outer surface of said tab.

8. The needle according to one or more of the preceding claims, characterized in that said tab comprises a groove with which said lip is associated rotatably and with play.

9. The needle according to one or more of the preceding claims, characterized in that said means for stopping the axial sliding of said ring comprise a shoulder and a collar, which are formed on said tab and delimit said groove.