WO2006013389A1

WO2006013389A1 - Biopsy apparatus and method

Info

Publication number: WO2006013389A1
Application number: PCT/GB2005/003100
Authority: WO
Inventors: David Rowley; Tim Drew
Original assignee: The University Court Of The University Of Dundee
Priority date: 2004-08-05
Filing date: 2005-08-05
Publication date: 2006-02-09
Also published as: GB0417400D0

Abstract

A biopsy apparatus (10) has a needle (18) and a driver assembly (20), which exerts a drive force on the needle (18) to drive it into tissue to take a tissue sample. In one embodiment the apparatus (10) has a driver (34) mounted for movement within a bore (36), which is driven by the force of a compressed spring (48) to impact the needle (18) and drive it forwards into the tissue to be sampled. A method for taking a tissue sample by driving a needle into tissue is also described.

Description

BIOPSY APPARATUS AND METHOD

Field of the invention

The present invention relates to biopsy apparatus and to a method of taking a tissue sample. In particular, but not exclusively, the present invention relates to biopsy apparatus of a type suitable for taking a bone sample.

Background of the Invention A biopsy procedure is the removal and examination of a sample of tissue from a living body for diagnostic purposes. Biopsy samples are typically taken from the iliac crest of the right or left pelvis coxal bones.

Biopsies are often carried out using a hole saw device, such as those shown at 1 and 2 in Figures Ia and Ib of the drawings . Each of the hole saw devices 1 and 2 are hollow and include saw-toothed ends 3 and 4, respectively. The devices 1, 2 are rotated by hand and pushed into the bone to slowly cut the bone and take a tissue sample. The tissue sample is in the form of a core of material stored within the hollow tube of the device 1, 2.

This procedure is time-consuming and a source of serious discomfort for the patient. Also, the devices do not always deliver a satisfactory biopsy core. For example, the sample can be broken, twisted, compacted or otherwise damaged during the _/cutting process.

Description of the invention

It is amongst the objects of embodiments of the present invention to obviate or mitigate at least one of the foregoing disadvantages.

In particular, it is amongst the objects of embodiments of the invention to provide an improved biopsy apparatus. According to a first aspect of the present invention, there is provided biopsy apparatus comprising: a needle for taking a tissue sample; and a driver assembly for exerting a drive force on the needle to drive the needle into tissue to take a tissue sample.

The invention offers advantages over known apparatus in that the driver assembly rapidly drives the needle into the tissue to take a sample. This is in contrast to known apparatus, such as hole saw type devices which are manually rotated and slowly pushed into tissue to take a sample.

The invention provides advantages over known apparatus of this type in that a tissue sample or biopsy core is taken more reliably, and thus with less damage to the sample, and in a fraction of a second, thereby subjecting the patient to considerably less discomfort.

It will be understood that references herein to a needle are to a generally hollow, elongate member, with a sharp point or end for puncturing tissue. However, the term equally encompasses any other member of a similar type and capable of performing the same function.

It will also be understood that references herein to biopsy apparatus are to apparatus of a type suitable for taking a tissue sample, most particularly a bone sample. The driver assembly is preferably adapted to exert an axial drive force on the needle, to drive the needle in a direction along a length thereof and into the tissue.

The driver assembly may be arranged to impact the needle to drive the needle into the tissue to be sampled. For example, the driver assembly may include a moveable driver, that is a driver mounted for movement relative to a part or remainder of the apparatus, the driver adapted to impact the needle to drive the needle into the tissue. Providing the needle separately from and adapted to be impacted by the driver assembly may facilitate subsequent removal of the tissue sample. This is because the needle may be readily released from the apparatus for removal of the sample, which may be achieved by pushing the sample out of the needle, or by drawing the sample out of the needle under a vacuum. It will be understood that by arranging the driver assembly to impact the needle, the needle may be rapidly driven into the tissue to take the tissue sample, with the associated advantages discussed above. In an alternative embodiment, the needle may be coupled to the driver assembly, that is releaseably coupled to the driver assembly or provided as an integral part of a component of the driver assembly. For example, the needle may be coupled to or provided as part of a moveable driver of the driver assembly, the driver moveable to thereby drive the needle into the tissue. In this alternative, the driver assembly may equally be arranged to rapidly drive the needle into the tissue to take the tissue sample, with the advantages discussed above. The driver assembly may include a loading device adapted to generate a drive force for driving the needle into the tissue. The loading device may comprise a spring, piston or the like and may be adapted to selectively exert a generated drive force on the needle. The loading device provides sufficient energy to drive the needle into the tissue to be sampled. For example, a loading device comprising a spring generating about 7.5 joules can provide sufficient kinetic energy to a needle to drive it into bone when obtaining a bone sample. The loading device may be adapted to selectively exert a generated drive force on a moveable driver of the driver assembly, and thus ultimately upon the needle. The driver may be moveable to load the loading device; for example, to compress the spring and generate the drive force. Alternatively, the loading device may be adapted to be moved relative to the moveable driver and thereby loaded; for example, the spring may be urged against the driver. It will equally be understood that the spring may be adapted to be placed in tension to generate the drive force, by appropriate location of the spring relative to the driver. The loading device may comprise a load member adapted to exert a force upon the driver, to move the driver and thereby load the loading device (for example, to compress the spring, or to place the spring in tension, as appropriate) . The apparatus may comprise a barrel or body, the driver mounted for movement within the barrel, and the load member also mounted within the barrel and moveable to translate the driver relative to the barrel to load the loading device. As will be described below, when the driver is released, the driver may be translated along the barrel towards the needle, or carrying the needle therewith, to drive the needle into the tissue. The loading device may also comprise a loading arm, lever or the like for translating the load member relative to the barrel. The loading arm may be coupled to the load member, and also pivotally coupled to the barrel, so as to provide a mechanical advantage in the movement of the load member. In other embodiments the driver assembly may be adapted to receive a source of stored energy, such as a cylinder of compressed gas or an explosive charge.

The driver assembly may also include means for storing the generated drive force. This may facilitate selective application of the drive force on the needle, for example, when one or both of the following conditions is satisfied: when a drive force has been generated which is sufficiently large to cause the needle to adequately penetrate the tissue; and to prevent accidental or unintentional operation of the apparatus and thus premature exertion of a drive force on the needle. The force storing means may comprise at least one restraint for preventing operation of the apparatus, in particular for preventing movement of the driver, to thereby store the generated drive force. For example, the force storing means may include a restraint adapted to releaseably engage the driver to prevent movement of the driver and thus exertion of a drive force on the needle. The restraint may be adapted to be selectively released from engagement with the driver, to thereby release the driver and permit exertion of the drive force on the needle.

The apparatus may comprise a safety mechanism for preventing accidental or unintentional operation of the apparatus and thus premature exertion of a drive force on the needle. The safety mechanism may form part of the force storing means, and may include at least one, preferably a plurality of such restraints for restraining the driver assembly. This may provide at least two layers or levels of safety, by requiring each of the restraints to be released before the needle may be driven into the tissue to take the tissue sample. In an embodiment of the invention, the safety mechanism may be adapted to releasably engage the moveable driver to prevent premature movement of the driver, as described above.

The needle may be moveable between a retracted position located within a body or barrel of the apparatus and an extended position where the needle extends at least partially from the body of the apparatus, for taking the sample. The needle may be urged from the retracted to the extended position by the driver assembly. The apparatus may comprise a needle assembly having a plurality of needles and may, in one embodiment, include a first, outer needle and a second, inner needle, the inner needle located within the outer needle, and both the inner and outer needles adapted to be driven into tissue by the driver assembly to take a tissue sample. The inner and outer needles may be adapted for taking different tissue samples. For example, the inner needle may be adapted to be driven into bone and subsequently removed such that a bone sample may be extracted, and a remaining bone marrow sample may then be extracted from the outer needle, either subsequent to removal from the tissue, or through the outer needle with the outer needle remaining in place within the tissue. This may be achieved by extracting the bone marrow under a vacuum, for example, by coupling a syringe or the like to the outer needle.

According to a second aspect of the present invention, there is provided a method of taking a tissue sample comprising the steps of: providing a needle for taking a tissue sample; and exerting a drive force on the needle using a driver assembly, to drive the needle into tissue to take a tissue sample.

The method may comprise causing the driver assembly to impact the needle to drive the needle into tissue to take the tissue sample. This may be achieved by impacting a moveable driver of the driver assembly against the needle. Alternatively, a driver assembly may be provided where the needle is coupled to a moveable driver, and the driver may be moved to drive the attached needle into the tissue.

The method may comprise extracting the tissue sample from the needle, which may be achieved by removing the needle from the tissue and subsequently extracting the tissue sample, or by removing the tissue sample through the needle with the needle still embedded in the tissue.

The method may comprise providing a needle assembly including a first, outer needle and a second, inner needle; locating the inner needle within the outer needle; and driving the inner and outer needles together into the tissue to take a tissue sample. The inner needle may then be removed from the tissue and a tissue sample, such as a bone sample, removed from the inner needle. With the outer needle still within the tissue, a separate tissue sample, such as a bone marrow sample, may then be extracted. Alternatively, marrow remaining in the outer needle subsequent to removal of the inner needle may then be extracted. This may be achieved by extracting the bone marrow under a vacuum, such as by coupling a syringe to the outer needle.

Brief Description of the Drawings

Embodiments of the present invention will now be described, with reference to the accompanying drawings, in which:

Figs. Ia and Ib are side views of conventional hole- saw devices;

Fig. 2 is a side view of a biopsy apparatus in accordance with a preferred embodiment of the present invention, shown in an uncocked configuration;

Figs. 3a and 3b are side and plan views of the human pelvis;

Fig. 4 is a longitudinal cross-sectional view of the biopsy apparatus of Fig. 1, shown in a cocked configuration;

Fig. 5 is a view of the biopsy apparatus of Fig. 1 taken from the other side, and shown during movement between the uncocked and cocked configurations of Figs. 1 and 4, respectively; Fig. 6 is a view of the biopsy apparatus of Fig. 1 shown following activation where a needle of the apparatus has been driven to an extended position to take a tissue sample; and Fig. 7 is a side view of a needle assembly forming part of a biopsy apparatus in accordance with an alternative embodiment of the present invention.

Detailed Description of Some Aspects of Preferred Embodiments of the Invention

Turning firstly to Fig. 2, there is shown a side view of a biopsy apparatus in accordance with a preferred embodiment of the present invention, the biopsy apparatus indicated generally by reference numeral 10, and shown in the Figure in an uncocked configuration.

The biopsy apparatus 10 takes the form of a biopsy gun, and is typically utilised to take a tissue sample from the iliac crest 12 of a coxal bone 14, which is illustrated in Fig. 3a. Fig. 3a actually shows the right coxal bone 14 of a typical human pelvis 16, which is shown in cross- section in Fig. 3b.

The biopsy apparatus 10 generally comprises a needle 18 for taking a tissue sample, and a driver assembly 20 for exerting a drive force on the needle 18 to drive the needle 18 into tissue (in this case, the iliac crest 12 of the coxal bone 14), to take a tissue sample. The needle 18 and driver assembly 20 are illustrated in Fig. 4, which is a longitudinal cross-sectional view of the biopsy apparatus 10 of Fig. 1, shown in a cocked configuration. Movement of the apparatus 10 between the uncocked configuration of Fig. 2 and the cocked configuration of Fig. 4 will be described in more detail below, with reference also to Fig. 5, which is a view of the biopsy apparatus 10 of Fig. 2 shown during movement between the uncocked and cocked configurations.

In general terms, the biopsy apparatus 10 is operated to drive the needle 18 from a retracted position, shown in Fig. 4, to an extended position, shown in Fig. 6. The apparatus 10 is used to take a tissue sample by pressing a needle sheath 22 against the skin of a patient and then driving the needle 18 through the skin to pierce the iliac crest 12 of the coxal bone 14. As will be described below, the needle 18 is rapidly driven into the iliac crest 12, piercing the bone such that a biopsy core is taken within the hollow needle 18. The biopsy core/tissue sample comprises cortical and cancellous bone tissue, and is obtained by withdrawing the needle 18 from the iliac crest 12, releasing the needle 18 from the apparatus 10 and then extracting the biopsy core. The core is extracted either by mechanically pushing the core out of the hollow needle 18, or by extracting the core under a vacuum, for example, by coupling a syringe (not shown) to the needle 18 and drawing the core out. The structure and method of operation of the biopsy apparatus 10 will now be described in more detail.

The apparatus 10 includes a barrel 24, with a needle block 26 coupled to the barrel 24 at one end, and a breech 28 at an opposite end. A stock 30 is coupled to the breech 28 and an end cap 32 is coupled to the stock 30 at the rear end of the apparatus 10.

The barrel 24, breech 28 and stock 30 house the driver assembly 20, which includes a driver 34 mounted for movement within a bore 36 of the barrel 24. The driver 34 includes a mass 38 and a needle striker 40 which is arranged to impact the needle 18, to drive the needle from the retracted position of Fig. 4 to the extended position of Fig. 6, to take a tissue sample. The driver 34 also includes a spindle 42 coupled to the mass 38, the spindle extending through a bore 44 in the breech 28.

The driver assembly 20 also comprises a loading device 46, which includes a spring 48 located around the spindle 42 in a bore 50 of the mass 38, and which extends between an end face of the mass 38 and a face 52 of the breech 28. At an end of the spindle 42 opposite the striker 40, the spindle 42 carries a catch 54 which is selectively engaged by a trigger latch 56. As will be described below, the latch 56 forms part of a force storing means for storing the generated drive force, that is, for retaining compression of the spring 48. This provides a drive force for driving the striker 40 to impact the needle 18.

The loading device 46 includes a load member in the form of a ram 58, which is moveable along the barrel bore 36 to translate the mass 38 and load the spring 48. In addition, the loading device 46 includes a loading arm in the form of lever 60, which is pivotally coupled to the stock 30. A rod 62 extends between the lever 60 and the ram 58, and is pivotally coupled to a slider 64 by a pin 66, which travels in a slot 68 that extends part way along a length of the barrel 24. In this fashion, rotation of the lever 60 about a pivot 70 translates the slider 64 carrying the ram 58 along the barrel bore 36. The rod 62 is coupled between the lever 60 and slider 64 so as to provide a mechanical advantage in the movement of the slider. It will be noted that the ram 58 includes an aperture 72 in which the striker 40 is received, to facilitate translation of the mass 38.

The means for storing the generated drive force comprises first, second and third restraints 74, 76 and 78. The first restraint 74 includes a lever latch 80 which pivots about a pin 82 and which is arranged to engage in circumferential detents 84 in the mass 38. The lever latch 80 is shown in Fig. 4 in a disengaged position, and further operation of the latch 80 will be described below.

The second restraint 76 includes a safety latch 86, pivoted about a pin 88. The safety latch 86 is normally biased by a spring 44 into engagement with a mass detent 84 or into a position where it will serve for engaging an end face 92 of the mass 38. The safety latch 86 thus prevents translation of the mass 38 in a direction towards the needle 18.

The third restraint is a trigger assembly 78, which includes a trigger 96 that, when depressed, releases the trigger latch 56. The trigger latch 56 is then pivoted about pin 98 by a spring 100, to release the spindle catch 54. As will be described, it is only by selectively releasing each of the lever latch 80, safety latch 86 and trigger latch 56 that the striker 40 may be allowed to travel forwards and strike the needle 18.

The procedure for moving the biopsy apparatus 10 from the uncocked position of Fig. 2 to the cocked position of Fig. 4 is as follows. In an initial, uncocked position, the mass 38 is at an extreme end of its travel, lying adjacent the ram 58 with the striker 40 located in the aperture 72. An operator first depresses a clip 102 on lever 60, releasing clip 102 from a housing 103 to permit the lever to move from the latched position of Fig. 4. The operator then pivots the lever 60 to the position shown in Fig. 5. This translates the ram 58 along the barrel bore 36, carrying the mass 38 and striker 40. As the lever 60 pivots away from the barrel 24, a latch pin 104 is moved away from the lever latch 80, which then pivots about pin 82 to a position where it will engage a first detent 84.

Movement of the ram 58 along the barrel bore 36 carries the mass 38, and cam surfaces 108 on the mass 38 deflect the safety latch 86, which successively engages the detents 84. This permits movement of the mass 38 along the bore 36 away from the needle 18, but restrains return movement to the position of Fig. 4. In a similar fashion, the lever latch 80, when released by the latch pin 104, successively engages in the detents 84, to provide a double lock or latch of the mass 38. As the ram 58 travels along the barrel bore 36, it encounters the safety latch 86, and a cam surface 106 on the ram 58 abuts a corresponding cam surface on the safety latch 86, pivoting the latch about pin 88 to facilitate passage of the ram 58 beyond the safety latch 86, if required.

The lever 60 has now been brought to the position of Fig. 5, fully compressing the spring 48, and bringing the catch 54 into abutment with a face 110 of the trigger latch 56. This rotates the latch 56 to the position of Fig. 4, thereby locking the spindle 42. This movement of the trigger latch 56 deflects and resets the trigger 96, ready for a firing procedure. The lever 60 is then rotated back towards the Fig. 4 position, and the apparatus 10 is now fully cocked and ready for use. It will be noted that when the lever 60 is returned to the Fig. 4 position, the latch pin 104 releases the lever latch 80 from engagement in the respective mass detent 84, and the clip 102 re-engages the housing 103, thereby locking the lever 60. This movement also returns the ram 58 to its start position, shown in Fig. 4, and the apparatus 10 is then cocked and ready for use.

The apparatus 10 is operated to take a tissue sample as follows. Firstly, a protective needle cap 112 is removed and the needle sheath 22 is pressed against the skin of a patient in the region of the iliac crest 12. The safety latch 86 is then depressed, to rotate the latch to a position where it will permit passage of the mass 38 along the barrel bore 36 towards the needle 18. The trigger 96 is then depressed and rotates about pivot 114, releasing the trigger latch 56 which rotates about pivot 98 and releases the catch 54. The stored force in the compressed spring 48 then drives the mass 38 forwards along the barrel bore 36, impacting the striker 40 against the needle 18. This drives the needle 18 forwards (as shown in Fig. 6) and into the iliac crest 12, such that a sample of bone tissue is taken within the hollow needle 18. The apparatus 10 is then pulled back, drawing the needle 18 out of the tissue. A lock ring 116 is then released, such that the needle sheath 22 and needle 18 may be removed from the apparatus 10. The bone sample is then extracted from within the needle 18 by pushing the sample out of the needle, or by drawing it out under a vacuum, for example, by coupling a syringe or the like to the needle 18. The needle 18 may be sterilised or replaced with a fresh, sterile needle, and the apparatus 10 reset and reused. However, the apparatus 10 may be disposable and many of the parts may be of plastics materials. Turning now to Fig. 7, there is shown a alternative needle assembly for the biopsy apparatus 10, provided as an alternative to the needle 18. The needle assembly is indicated generally by reference numeral 18a, and comprises a first, outer needle 118, and a second, inner needle 120. The inner needle 120 is located within the outer needle 118, and both needles 118, 120 are driven into the tissue together by the needle striker 40, in the fashion described above. The inner needle 120 takes a sample of cortical and cancellous bone tissue from the iliac crest 12, and the needles 118, 120 are released from the apparatus 10 with the needles remaining embedded in the tissue. The inner needle or trocar 120 is then extracted from the outer needle 118, and the bone tissue removed. With the outer needle 118 remaining in the tissue, a syringe or like equipment is coupled to the needle 118, and is used to extract a bone marrow tissue sample. The outer needle 118 is then removed from the tissue. Alternatively, the needle assembly 18a may be withdrawn from the iliac crest 12, the inner needle 120 removed from the outer needle 118, and bone marrow remaining in the outer needle 118 extracted. Operation of the apparatus 10 is otherwise the same as that described above.

Various modifications may be made to the foregoing without departing from the sprit and scope of the present invention.

For example, the needle may be coupled to the driver assembly, that is releaseably coupled to the driver assembly or provided as an integral part of a component of the driver assembly. The needle may be coupled to or provided as part of a moveable driver of the driver assembly, the driver moveable to thereby drive the needle into the tissue. In this alternative, the driver assembly may equally be arranged to rapidly drive the needle into the tissue to take the tissue sample, with the advantages discussed above.

The loading device may be adapted to be moved relative to the moveable driver and thereby loaded; for example, the spring may be urged against the driver. The spring may be adapted to be placed in tension to generate the drive force, by appropriate location of the spring relative to the driver. The driver assembly may be adapted to receive a source of stored energy, such as a cylinder of compressed gas or an explosive charge. Marrow remaining in the outer needle subsequent to removal of the inner needle may be extracted after removal of the inner needle. This may be achieved by extracting the bone marrow under a vacuum, such as by coupling a syringe to the outer needle.

Claims

1. A biopsy apparatus (10) comprising: a needle (18) for taking a tissue sample; and, a driver assembly (20) for exerting a drive force on the needle to drive the needle into tissue to take a tissue sample.

2. A biopsy apparatus (10) according to claim 1 wherein the driver assembly (20) is adapted to exert an axial drive force on the needle (18), to drive the needle in a direction along a length thereof and into the tissue.

3. A biopsy apparatus (10) according to claim 1 or claim 2 where the driver assembly (20) is arranged to impact the needle (18) to drive the needle into the tissue to be sampled.

4. A biopsy apparatus (10) according to claim 3 where the driver assembly (20) comprises a moveable driver (34) mounted for movement relative to a part or remainder of the apparatus (10), the said driver (34) being adapted to impact the needle (18) to drive the needle into the tissue.

5. A biopsy apparatus (10) according to any one of claims

1 to 4 wherein the needle (18) is releasable from the apparatus (10) for removal of the sample.

6. A biopsy apparatus (10) according to claim 1 or claim 2 wherein the needle (18) is releasably coupled to a moveable driver (34) of the driver assembly.

7. A biopsy apparatus (10) according to claim 1 or claim

2 wherein the needle (18) is provided as an integral part of a component of a moveable driver (34) of the driver assembly (20) .

8. A biopsy apparatus (10) according to any one of the claims 1 to 7, wherein the driver assembly (20) further comprises a loading device (46), adapted to generate a drive force for driving the needle (18) into the tissue.

9. A biopsy apparatus (10) according to claim 8 wherein the loading device (46) comprises a spring (48) .

10. A biopsy apparatus (10) according to claim 8 wherein the loading device (46) comprises a piston.

11. A biopsy apparatus (10) according to any one of claims 8 to 10 wherein the loading device (46) is loaded by movement of the driver (34) .

12. A biopsy apparatus (10) according to any one of claims 8 to 10 wherein the loading device (46) is adapted to be moved relative to the moveable driver (34) and thereby loaded.

13. A biopsy apparatus (10) according to any one of claims 8 to 11 wherein the loading device (46) comprises a load member (58) adapted to exert a force upon the driver (34), to move the driver and thereby load the loading device.

14. A biopsy apparatus (10) according to claim 13 further comprising a barrel (24) or body wherein the driver (34) is mounted for movement within the barrel, and the load member (58) is mounted within the barrel and moveable to translate the driver relative to the barrel to load the loading device (46) .

15. A biopsy apparatus (10) according to claim 13 or 14 wherein the loading device (46) further comprises a loading arm or lever (60) for translating the load member (58) relative to the barrel (24) .

16. A biopsy apparatus (10) according to claim 15 wherein the loading arm (60) is coupled to the load member (58), and also pivotally coupled to the barrel (24) , so as to provide a mechanical advantage in the movement of the load member (58) .

17. A biopsy apparatus (10) according to any one of claims 1 to 7 wherein the driver assembly (20) is adapted to receive a source of stored energy, to generate a drive force for driving the needle (18) into the tissue.

18. A biopsy apparatus (10) according to claim 17 where the source of stored energy is a cylinder of compressed gas or an explosive charge.

19. A biopsy apparatus (10) according to any one of claims 1 to 16 wherein the driver assembly (20) includes means (74,76,78) for storing the generated drive force, for selective application of the drive force on the needle (18) .

20. A biopsy apparatus (10) according to any one of claims 4 to 16 wherein the driver assembly (20) further comprises at least one releasable restraint (76,77,78) for preventing movement of the driver (34), to thereby store the generated drive force.

21. A biopsy apparatus (10) according to any one of the preceding claims further comprising a safety mechanism

(76,86,88) for preventing accidental or unintentional operation of the apparatus (10) .

22. A biopsy apparatus (10) according to claim 21 wherein the safety mechanism (76,86,88) includes at least one restraint (86) for releasably restraining the driver assembly (20) .

23. A biopsy apparatus (10) according to any one of the preceding claims wherein the needle (18) is moveable between a retracted position located within a body (22) of the apparatus and an extended position, where the needle (18) extends at least partially from the body of the apparatus, for taking the sample.

24. A biopsy apparatus (10) according to any one of the preceding claims which comprises a needle assembly having a plurality of needles (118,120) .

25. A biopsy apparatus (10) according to any one of the preceding claims for use in taking bone samples.

26. A biopsy apparatus (10) according to claim 24 wherein the needle assembly comprises a first, outer needle (118) and a second, inner needle (120), the inner needle (120) located within the outer needle (118), and both the inner and outer needles are adapted to be driven into tissue by the driver assembly (20) to take a tissue sample.

27. A biopsy apparatus (10) according to claim 26 wherein the inner and outer needles (120,118) are adapted for taking different tissue samples.

28. A biopsy apparatus (10) according to claim 26 or 27 for use in obtaining samples of bone and bone marrow.

29. A method of taking a tissue sample comprising the steps of: providing a needle (18) for taking a tissue sample; and exerting a drive force on the needle using a driver assembly (20), to drive the needle into tissue to take a tissue sample.

30. A method according to claim 29 wherein the driver assembly (20) impacts the needle to drive the needle (18) into tissue to take the tissue sample.

31. A method according to claim 29 wherein the needle (18) is coupled to a moveable driver (34) of the driver assembly, and the driver (34) is moved to drive the attached needle into the tissue.

32. A method according to any one of claims 29 to 31 further comprising the step of: removing the needle from the tissue and subsequently extracting the tissue sample.

33. A method according to any one of claims 29 to 31 further comprising the step of: removing the tissue sample through the needle with the needle still embedded in the tissue.

34. A method according to any one of claims 29 to 33 where the tissue sample is bone.

35. A method according to any one of claims 29 to 31 further comprising the steps of: providing a needle assembly including a first, outer needle (118) and a second, inner needle (120) ; locating the inner needle within the outer needle; and driving the inner and outer needles together into the tissue to take a tissue sample.

36. A method according to claim 35 further comprising the steps of: removing the inner needle (120) from the tissue and a removing a first tissue sample from the inner needle; and extracting a second tissue sample with the outer needle (120) .

37. A method according to claim 35 where the first tissue sample is bone and the second tissue sample is bone marrow.

38. A method according to claim 37 where the second, bone marrow, sample is extracted through the outer needle (120) under a vacuum.