GB2223409A

GB2223409A - Vacuum operated biopsy needle sampling

Info

Publication number: GB2223409A
Application number: GB8820029A
Authority: GB
Inventors: Azin Fazal
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-08-23
Filing date: 1988-08-23
Publication date: 1990-04-11
Anticipated expiration: 2008-08-23
Also published as: GB2223409B; GB8820029D0

Abstract

Apparatus for performing a biopsy comprises a hollow needle (14), a tubular holder (10, 11, 12) for the needle, and for a sealed vacuum container (34, Fig. 4) whose end locates against an end face (36) of a blind bore (19) of a plunger (13). The vacuum container (34) is brought into communication with the distal end (20) of the needle (14), as the needle (14) punctures the tissue, in response to relative movement between the needle (14) and the container (34) in the advancing plunger (13), as a threaded stem (15) of the needle is forced to rotate upon displacement within the holder (10, 11, 12) through a square holder bore (24), until a cross-piece (16) of the needle becomes aligned with, and enters, and is displaced relatively along a plunger slot (23) into puncturing contact with the end of the container. <IMAGE>

Description

BIOPSY APPARATUS In a known method of performing a liver biopsy, a hollow "Menqhini" needle projecting from a syringe is inserted into the liver through the abdomen wall while at the same time a plunger is withdrawn from the syringe to create a vaccum which retains the liver sample in the bore of the needle. To prevent the sample passing out from the other end of the needle, the distal end or the bore is blocked by a rod but with sufficient clearance to permit the passage of air.

After the needle has been withdrawn, the sample is ejected from the bore of the needle and into a bottle containing an aqueous fixative such as a formaldehyde solution.

The entire process therefore involves a number of stages and, moreover, it is in practice difficult to co-ordinate the withdrawal of the syringe plunger with the simultaneous forward movement of the syringe to pierce the liver capsule.

According to the present invention, this difficulty is overcome by providing apparatus for performing a biopsy in which a vacuum source is brought into communication with the distal end of a hollow needle in response to relative movement between the needle and a holder for the needle as the needle punctures the body tissue.

In a preferred embodiment, communication with the vacuum source is achieved when the distal end of the needle pierces a sealed vacuum container.

The insertion of the needle into the body tissue is preferably accompanied by relative rotation between the needle and the vacuum container, the container preferably being inserted within a plunger in the holder and being movable axially toward the distal end of the needle only when the needle has a predetermined orientation relative to the container. For example the needle may carry a locating member which permits relative axial movement between the plunger and the needle only when aligned with a corresponding opening in the plunger.

In the accompanying drawings, by way of example only: Figs. la-le are perspective sketches showing the components of a syringe embodying the invention for performing a liver biopsy, Fig. 2 is a diagrammatic sketch of a needle assembly for use with the syringe of Fig. 1.

Fig. 3 is a diagrammatic sketch showing the needle assembly of Fig. 2 co-operating with the plunger component of Fig. 1, and Fig. 4 is a sketch of one form of sealed container with an optional end stop for use with the syringe of Fig.

1.

The illustrated syringe comprises a three part housing 10, 11, 12, each part consisting of a hollow cylindrical tube with the adjacent ends of the tubes being in screw threaded engagement with one another.

A cylindrical plunger 13 is slidably mounted for axial movement in the tubular housinq components 10, 11.

A hollow needle 14 (Fiq. 3) carries a screw threaded bar 15 of square cross-section with an associated cross-piece 16. The needle is retained within the housing components 11, 12 and projects through the orifice 17 in the end face of the component 12.

A sealed vacuum container 34 (Fig. 4) is inserted through an opening 30 in the end face 18 of the housing component 10, the container being received in a blind bore 19 of the plunger 13 with one end of the container abutting the end face 36 of the bore and the other end projecting from the end face 18 of the housing.

In use, the distal end portion 20 of the needle 14 initially lies within a hole 21 at the base of a slot 23 in the end face 22 of the plunger 13, the hole 21 communicating with the bore ;9, and the cross-piece 16 of the T-bar abutting the end face 22 of the plunger 13. In this position, the cross-piece 16 lies transverse to the slot 23, as shown in Fig. 3, and the tip 31 of the needle just touches the cap 33 of the vacuum container 34.

However, as pressure is applied to the needle via the plunger 13 and the sealed container when taking a sample, the cross-piece 16 is forced to rotate through 900 as the thread formed on the stem 15 of the square section T-bar passes through the square opening 24 in the end face 35 of the housing component 11. This brings the cross-piece 16 into line with the slot 23 so that further applied pressure urges the plunger 13 toward the needle 14 and causes the tip 31 at the distal end 20 of the needle to pierce the cap 33 of the sealed vacuum container.

The resulting suction draws a sample of the body tissue through the bore of the needle 14 and into the vacuum container. The container may already contain a liquid fixative such as a formaldehyde solution. The needle is then withdrawn and the container removed from the syringe 13.

In one alternative arrangement, as illustrated in Fig.

4, the sample is drawn only partially up the bore of the needle 11 against a stop. The stop 36 is carried at one end of a fine wire or rod 37 which extends the length of the sealed container and projects beyond the sealed cap 33 of the container. This can prevent the sample disintegrating as it is drawn up the bore of the needle.

All components, with the exception of needle 14, can be easily moulded in plastics materials, and the syringe could therefore be made disposable.

Claims

1. Apparatus for performing a biopsy, the apparatus comprising a hollow needle, a tubular holder for the needle, and a vacuum source, the arrangement being such that the vacuum source is brought into communication with the distal end of the needle in response to relative movement between the needle and the holder as the needle punctures the body tissue.

2. Apparatus according to claim 1 wherein the vacuum source comprises a sealed vacuum container and communication with the vacuum source is achieved when the distal end of the needle pierces the container.

3. Apparatus according to claim 2 wherein the needle pierces the container in response to relative axial movement between the needle and the container, the needle and the container being rotatable relative to one another in response to the said relative movement between the holder and the needle, and wherein the relative axial movement between the container and the needle is permitted only when the needle has a predetermined orientation relative to the container.

4. Apparatus according to claim 3 further comprising a tubular plunger slidably mounted in the holder, the plunger normally separating the container and the needle but having a slot at one end for receiving a cross-piece associated with the needle to permit the said relative axial movement when the cross-piece and slot are aligned with one another.

5. Apparatus according to claim 4 wherein the holder comprises a plurality of axially arranged plastic moulded tubular sections releasably engaged with one another.

6. Apparatus; ac-cardinq to- claim 5' wherein a portion of the needle carries a screw thread and .the holder includes.

an internal passage for receiving the screw thread, the cross-section of the passage being equal to the crosssection of the threaded portion of the needle.

7. Apparatus according to claim 2 wherein the bore of the needle includes a stop located such that the biopsy sample is drawn only partially up the bore when the needle punctures the body tissue.

8. Apparatus according to claim 7 wherein the stop is carried at one end of a fine wire or rod extending axially from the vacuum container.

9. Apparatus for peforming a biopsy and substantially as herein described with reference to the accompanying drawings.