CA2211422A1

CA2211422A1 - Methods and devices for automated biopsy and collection of soft tissue

Info

Publication number: CA2211422A1
Application number: CA 2211422
Authority: CA
Inventors: Mark A. Ritchart; J. Michael Stuart; Fred H. Burbank; Kenneth M. Galt
Original assignee: Individual
Current assignee: Biopsys Medical Inc
Priority date: 1995-02-10
Filing date: 1996-02-08
Publication date: 1996-08-15
Also published as: US20110160611A1; EP0808129B1; JPH10513384A; US20130197392A1; US20060167377A1; ES2231586T3; US20040019299A1; US20130197393A1; WO1996024289A3; JP3868977B2; EP1197180A2; EP1197180B1; JP3706139B2; JP2005288187A; US8591435B2; US20140088412A1; US7981050B2; EP0808129A2; US20020120212A1; US8808199B2

Abstract

Instruments for performing percutaneous biopsy procedures are disclosed, which have advantageous features for improving functionality and performance over prior art devices. These instruments comprise two types, single-use devices, and multiple-use devices having active tissue capture capability. Improved features include the ability to retrieve and evaluate multiple tissue samples during a single insertion procedure, without physical handling of the samples, as well as constructional features, such as a molded tissue cassette housing, variant vacuum port embodiments suited for different tissue environments, and a method for backflushing the instrument to remove biological debris, among others.

Description

WO 96/24289 PCT~US96101655 MEII I~DS AND Dl~VIOES ~OR AU I~ATED BIOPSY
AND C~OIIECIIC~ OF SOFr TI~SUE

~ss-Reference to Relatcd~4~li~ions This application is a cnntim~tion-in-part of co-pending parent application SN
08/217,246, filed March 24, 1994.

~leld of 91C ~vention The present invention relates to methods and devices for tissue sampling, and more specifically to improved biopsy instruments and methods for acquinng subcutaneous biopsies and for removing lesions.

R~r~ d of thP ~nventioll It is often desirable and frequently n~c~s~ty to sample or test a portion of tissue from hllm~n.s and other ~nim~ls, particularly in the (li~gnnsis and tre~tm~nt of patients with cancerous tumors, pre-m~lign~nt conditions, and other diseases or disorders. Typically, in the case of cancer, when the physician establishes by means S of procedures such a~s palpation, x-ray, or ultrasound im~ing that suspicious circ~ mst~n~Ps exist, a biopsy is performed to cl~termine whether the cells are cancero~s. Biopsy may be done by an open or percutaneous tec~nique. Open biopsy,which is an invasive surgical procedure using a scalpel and involving direct vision of the tar~et area, removes the entire mass (excisional biopsy) or a part of the mass 10 (incisional biopsy). Percutaneous biopsy, on the other hand, is usually done with a needle-like instrument through a relatively small incision, blindly or with the aid of an artificial im~in~ device, and may be either a fine needle aspiration (FNA) or a core biopsy. In FNA biopsy, individual cells or clusters of cells are obtained for cytologic tion and may be prepared such as in a Papanicolaou smear. In core biopsy, as the term s l~.st~, a core or fragment of tissue is obtained for histologic ";"~tion which may be done via a frozen section or paL~Ill section.
The type of biopsy utilized depends in large part on circumst~nr~-s present 5 with respect to the patient, and no single procedure is ideal for all cases. However, core biopsy is extremely useful in a number of conditions and is being used morefrequently by the medical ~r~r~ion.
Two types of image guided percutaneous core breast biopsy instruments are presently available. One such instrument is a springpowered single-use device, such 10 as the BIOPTY~ gun, available from C.R Bard, Inc. Such a gun is shown and described in U.S. Patents No. 4,699,154 and 4,944,308, as well as in U.S. Reissued Patent No. Re. 34,056, all of which are herein expressly incorporated by reference.
These devices are useful because of their inexpensive construction, enabling them to be economically used for only a single patient, and because they are lightweight and 15 easy to use. However, they also have disadv~nt~c. An important disadvantage is that the small core size makes it necessary to accurately place the needle when sampling small lesions. To sample a lesion thoroughly, many separate insertions must be made. Each time a new sample is taken, the device must be removed, and the breast or organ must be punctured again upon re-insertion of the device. This action 20 is tedious and time consl-ming.
A further disadvantage of such single-use guns is the needle typically used in such a device, e.g. the True CutOE needle m~mlfzlrtllred by Travenol Laboratories.
This needle optimally allows a roughly cylindrical shaped sample of tissue, termed a "core", to be obtained from a pointed, side cutting device, percutaneously, and 25 comprises a pointed inner stilette with a side-facing notch to receive tissue near its distal pointed end and an outer, sharpened sliding r~nmll~ In operation, once the lesion is targeted, the inner stilette is thrust into the organ or lesion of interest.
Tissue passively prolapses into the side facing notch and the outer c~nmll~ is rapidly advanced, thereby severing the sample of tissue cont~in~l within the notch.
Ullrollul~Lely7 the True Cut~ needle is rough on organs and lesions, often only obtaining small fr~m~nt~ of tissue, and is quite operator dependent -- some individuals are good at operating the device and some are not. It also is tissueS selective, n~f ~nin~ that the piercing stilette and sliding cutter caD "push away" the lesion of interest, particularly in situations where a relatively large lesion is surrounded by much softer tissue (i.e. fat).
The second type of image guided percutaneous core breast biopsy instrurnent currently available is a vacuum-~c~icted automatic core biopsy device. One such 10 sl-ccessful biopsy gun is shown and disclosed in related parent application SN
08/217,246, filed on March 24, 1994, which is commonly owned by the assignee of the present application and is herein incorporated by reference. This gun has the capability to active capture tissue prior to cutting the tissue. Active capture allows for sampling through non-homogeneous tissues, m.o~ning that the device is equally 15 capable of cutting through hard and so~ tissue. The gun also includes means to direct and position the cutting cl,~~ in ~I,iLI~y positions about and along its longitudinal axis, means for rapid and atraumatic removal of an ~IJil l ~y number of core sarnples with only a single needle insertion into the body and organ7 and means for coding and decoding the location from which the samples were obtained. Together, these 20 capabilities allow for more complete sampling of large lesions and for the complete removal of small lesions. This type of instrument has been ve~ ecf ~fi-l in p~l " ~iLI ii ~g the ob~ Irl 11 of a plurality of tissue samples from dirr~ locations with only a single needle insertion7 as well as in obtaining high quality samples in a manner which does not require direct h~n~lling of the samples by the operator.
25 However, it does not operate equally well in all procedures _nd in all bodilyen~ For example, instrument p~lr().."A"~ and success often varies dependent upon the type of body tissue being sampled; i.e. relatively fatty or relatively hard.

W O 96/24289 PCTrUS96/01655 What is needed then, are innovations for irnproving the quality and completeness of the tissue sample obtained using a single-use core biopsy instrument, as well as constructional improvements and variants with respect to the active capture type of instrument which will permit it to operate with maximum efficiency and to S operate equally well in all tissue environm~nt~

L ~ of ~e Tnven'don This invention addresses the afu, ~ "Lioned needs by pr~viding a number of important new features and innovations for the active capture type of biopsy instrument which each collectively or singly contribute to improved and more versatile operation. For example, such innovations include a molded tissue c~ette housing, permitting easy and inexpensive fabrication while also pr~ i U i,-g theh~n-lling and viewing of multiple tissue samples without physical contact by theinstrument operator. The housing is interconn~cterl with the piercing needle using a thumbwheel which permits the needle to rotate relative to the housing, thereby preventing the vacuum tube from wl~ing about the housing. Several variant vacuum port embo-lim~nt~ are disclosed, each of which have advantages in certaintissue environm~nt~ Also disclosed is a method for b~rkflll~hing biological debris from the instrument which builds up after repeated sampling procedures, without removing the instrument from the selected tissue location.
With respect to the single-use type of biopsy instrument, sever~l tissue captureembot1im~nt~ are disclosed for improving the capture process, so that complete and well preserved samples are obtained. Many of these embo-lim~nt~ are also applicable for use with the active capture instrument type.
More particularly, in one aspect of the invention, a biopsy instrument is provided which comprises a housing and a needle assembly, wherein the needle assembly incll~ c a tubular piercing n~ lb~l having a distal pointed end and a -laterally positioned tissue receiving port ~ ~Le to the distal pointed end whichopens into a tissue sample chamber. The tubular piercing member is rotatably rh~ to the housing and held in an axially fixed position within a selected tissue mass. The needle assembly further incl~ a ç~nmll~r cutting member adapted to ~ 5 coact with the tubular piercing member to cut a tissue sample from the tissue mass.
The tissue sample is transported to a ~ ~le end of the tubular piercing m~
by the cutting member as it is withdrawn l~ro~in~ally along the tubular piercingmember. An elongate knock-out pin is disposed coaxially within the tubular piercing lllc~ el and the l~nmll~r cutting member for the primdry putpose of dislodging the tissue sample from the cutting member at a precletPrrninPfl location as the cutting member is withdrawn.
Surprisingly, the inventors have found that ~l~r.ldl)ly, in order to Illi~lillli/~
tissue clogging of the cutter, the knock-out pin should have an e~ective ~ mPt~ or cross-sectional area of at least .030 inches, and the ratio of the effective ~ mPt~r of the knock-out pin to the inte~al tli~mPtPr of the c~nmll~r cutter should be at least approximately one-half.
In another aspect of the invention, a biopsy instrument in~ clçs an elongate hollow outer piercing needle having a lumen, a sharpened distal end for piercingtissue, and a lateral opening located proximal to the sharpened distal end for receiving a portion of a tissue mass positioned a(ljacPnt to the lateral opening. Also included are an elongate inner cutting r~nm-l~ having a lurnen, which is disposed coaxially and slidably within the outer piercing needle. The inner c~nmll~ has a sharpened distal end for cutting the portion of tissue protruding into the lateral opening of the outer piercing needle when the inner r~nmll~ slides distally past the lateral opening. This causes the portion of cut tissue to be deposited within the inner c~nnlll~ pr~J?cin~al to the distal end. A vacuum generator generates a vacuum pressure which fluidly commnnicates with the lateral opening through the inner r~nmll~ lumen. In such an embo~lim~nt it is often desirable to prevent the tissue sample from migrating ploxi~llally through the cutting r~nn~ lumen, so an inventive tissue stop device is disposed in the lumen of the inner r~nn~ which has a structure, pler~,l~ly a corkscrew portion of a linear wire, disposed ~ ~lly of the lateral oper~ing. This structure suff1ciently obstructs the lumen so that the tissue sampl~ cannot rnigrate S proxirnally past it.
In yet another aspect of the invention, a biopsy instrument includes an outer hollow ç~nmll~ having a distal end portion which c )mpn~es a plurality of leaftlets.
Each leaflet has a ~loxin~al end which is hinged to the outer r~nnlll~ wall and a distal end, and are each biased to pivot about their hinges to a closed position wherein the 10 distal ends of the leaflets contact one another. The instrument further includes an inner hollow c~nnnl~ and at least one of the inner and outer r~nm~ is slidable relative to the other ç~nmll~ so that first the inner ç~nnlll~ may be extended distally with respect to the outer ç~nmll~ to force the leaflets to an open position, and to cut and contain a tissue sarnple, and then the outer c~nn-ll~ rnay be extended distally with 15 respect to the inner r~nmll~ sufficiently so that the leaflets clear the inner c~nmll~ and snap closed about their hinges, thereby severing the tissue sample and co~ g it within the irmer ~nmll~
In a further aspect of the invention, a biopsy instrurnent has an outer hollow r~nmll~ having a sharpened distal end portion and an inner hollow c~nmll~ having a 20 distal portion which is biased to expand radially at its distal end. At least one of the r~nmll~s is slidable relative to the other c~nm-l~ so that first the inner ç~nmll~ rnay be extended distally with respect to the outer c~nmll~ such that the inner ~slnnlll~
distal portion expands radially to capture a tissue sarnple. Then the outer c~nnnl~
rnay be extended distally with respect to the inner ç~nnlll~ sufficierltly so that the 25 distal end portion of the inner ç~nmll~ is forced by the outer r~nnlll~ to close about and sever the tissue sarnple, thereby c )~ ,g the sarnple within the inner c~nmll~
The distal portion of the inner c~nmllzt rnay comprise, for exarnple, either an alligator tip having a pair of hinged jaws which are biased to expand radially, or a plurality of hooked extractors.
Still anot-her aspect of the invention involves a method for flll~hin~ debris forrn a biopsy i~ n~ll, which inrl~lde~ an outer piercing needle having a laterally S position~l tissue receiving port which opens into a tissue receiving charnber and an inner cutting c~nmll~ having an axial lumen and a sharpened distal end, which isdisposed coaxially and slidably within the outer piercing needle. Further included in the biopsy instrument is a vacuum lumen disposed beneath the tissue receiving port which fi~ther comprises at least one fluid comml~nication port disposed distally of the 10 distal end of the inner r~nmll~ when the inner r~nmll~ is in its fully advanced position. The inventive method inrl~ es the steps of advancing the inner e~nmll~ of the instrument so that it extends distally sufficiently to completely close off the tissue receiving port and then injecting a prrs~llri7~ fluid through one of the inner ç~nmll~
and the vacuum Illm( n~, so that the fluid flows through the fluid commlmication port 15 and into the oth-er one of the two lllmrn~, from which the fluid returns to its source, thereby flll~hing ~r~umlll~ted debris from the biopsy instrument.
The invention, together with additional features and advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying illustrative drawing.

20 Rnef Descnp~on of ~e Dlawirff~

Fig. 1 is a perspective view of an ~llt~)m~tic core biopsy device of the type shown and described in co-pending patent application SN 08/217,246;

Fig. 2 is a srhrm~tic plan view, from the left side, of a portion of the needle assembly of the device illustrated in Fig. 1, showing the device before it penetrates a 25 target lesion;

CA 022ll422 l997-08-08 Fig. 3 is a s~ ic plan view similar to Fig. 2, showing the device after it has penetrated the target lesion, in a position to begin collecting tissue samples;

Fig. 4 is a cross-sectional view, from the left side, of the needle assembly of the device illustrated in Fig. l;

SFig 5 is an enlarged perspective view of the portion of Fig. 1 delin~t~l by the numeral 5.

Fig. 6 is a cross-sectional view of one embodiment of the needle assembly illustrated in Fig 5;

Fig. 7 is a cross-sectional view taken along lines 7-7 of Fig. 6;

10Fig 8 is an enlarged cross-sectional view taken along lines 8-8 of Fig 3;

Fig. 9 is an enlarged cross-sectional view similar to Fig. 8, illustrating the withdrawal of the cutter after insertion of the needle into the target lesion;

Fig. 10 is an enlarged cross-sectional view similar to Fig. 8~ illustrating the prolapse of tissue into the tissue receiving port following the application of the 15 vacuum pressure;

Fig. 11 is an enlarged cross-sectional view similar to Fig. 8, illu~trating the ~imnlt~nPous rotation and distal advanc~m~nt of the cutter to cut off a tissue sample;

Fig. 12 is an enlarged cross-sectional view similar to Fig. 8, illustrating the p~ al withdrawal of the cutter with the tissue sample cont~in~cl therein;

Fig. 13 is an enlarged cross-sectional view of the int~f~ce between the al end of the tissue r~ tte and the tissue c~sette housing illustrated in Fig 4,showing the operation of the lmock-out pin to retain the tissue sample in the tissue c~sel~e as the cutter is withdrawn plv~ ally;

Fig. 14 is a cross-sectional view taken along lines 1~14 of Fig lO, Fig. 15 is a cross-sectional view taken along lines 15-lS of Fig 12, Fig. 16 is a cross-sectional view similar to Fig. 14, wherein the outer needle and inner cutter have been rotated a~~ l~Lely 90 degrees counterclockwise to take a second tissue sa~nple;

Fig. 17 is a cross-sectional view similar to Fig 15, wherein the outer needle and inner cutter have been rotated a~ ly 300 degrees counterclockwise, and a fourth tissue sample has been taken;

Fig 18 is a cross-sectional view of a second embodiment of the needle assembly shown in Fig. 3;

Fig. 19 is a cross-sectional view along lines 19-19 of Fig 18;

Fig. 20 is a cross-sectional view of a third embodiment of the needle assembly shown in Fig. 3;

Fig. 21 is a top plan sch~m~tic view of the tissue receiving port of a fourth modified needle assembly embodirnent;

Fig 22 is a cross-sectional view similar to Fig 3, illustrating a fifth modifiedneedle assembly embodiment;

Fig. 23 is a cross-sectional view through the tissue port of a needle assembly like that shown in Fig 5, illustrating a potential tissue binding situation under certain S operating regimP~;

Fig. 24 is a frAgrnPnt~ry cross-sectional view of the cutter portion of a sixth modified needle assembly embotlimPnt illustrating an inventive solution to prevent potential tissue binding situations like that illustrated in Fig. 23;

Fig 25 is a cross-sectional view of a prior art single-use biopsy device, of thetype shown and described in U.S. Patent No. 4,699,154;

Fig. 26 is a frAgmPnt~ry cross-sectional view of a modified needle assembly for a biopsy gun of the type illustrated in Fig. 25, illustrating the needle assembly in a first position for advancing the needle assembly through tissue to a selected tissue sample site;

Fig. 27 is a fr~nPnt~ry cross-sectional view of the needle assembly illustrated in Fig 26, showing the needle assembly in a second position for obtaining and cutting a tissue sample;

Fig. 28 is a fr~nPnt~ry cross-sectional view o~ the needle assembly illustrated in Fig 26, showing the needle assembly in a third position wherein the tissue sarnple 20 has been severed and is cont~inP~l in the tissue receiving port of the needle assembly;

WO 96/24289 PCTIUS96~01655 Fig 29 is a fr~gmrnt~y cross-section~I view of a second modified needle assembly for a biopsy gun of the type illustrated in Fig. 25, illustrating the needle assembly in a first position for advanc~m~nt into the selected tissue sample site;

Fig. 30 is a fr~gmrnt~ty cross-sectional view of the needle assembly illustratedS in Fig 29, showing the needle assembly in a second position af[er capture of a tissue sample;

Fig 31 is a sr~l~m~tic exploded view of a third modified needle assembly for a biopsy gun of the type illustrated in Fig. 25;

Fig. 32 is a srhrm~tic side elevational view of the needle assembly illus~ated in Fig. 31, showing the assembly in a first position approaching a selected tissue sa~nple;

Fig. 33 is a srhrm~tic side elevational view similar to Fig. 32, illustrating the needle assembly in a second position grabbing the selected tissue sample; and Fig. 34 is a srhrm~tic side elevational view similar to Fig. 32, illustrating the needle assembly in a third position after capture of the selected tissue sample.
l)es~ iQn of ~e Inven'don Referring now to Figs. 1, 4, and 5, a preferred embodiment of an automatic core biopsy device 10 of the type disclosed in related patent application SN
08/217,246 is illustrated. The illustrated biopsy instrument 10 comprises a housing 14 having a hinged lid 16. A needle assembly 18 extends out of the housing 14, and comprises a hollow outer piercing needle 20, an inner cutter 22 having a lumen 23 CA 022ll422 l997-08-08 W096/24289 PCTrUS96/01655 (Fig 5), a tissue cassette housing 24, and a tissue r~ette 26. The hollow outer piercing needle 20 further inclll~lP~ a tissue receiving port or bowl 28. A thumbwheel 30 i,ll~l~llllects the tissue c~ette housing 24 and the hollow outer piercing needle 20, preferably p~ rotation of the needle 20 without rotating the tissue ç~sette housing 24, as will be more completely described hereinbelow. A vacuum port 32 in the tissue c~sette housing 24 iS adapted for att:~lrl~m~nt to a vacuum source through a tube or tubing 34, in order to provide a vacuum at the tissue receiving port or bowl 28. Preferably, the vacuum is supplied through a separate vacuum lumen 35, but may ~lt~n~tively or ~imnlt~n~ously be supplied directly through the lumens of the hollow outer piercing needle 20 and the inner cutter 22, respectively, if desired.
Telescopically and coaxially arranged within the hollow outer piercing needle 20 and the inner cutter 22 is a knock-out pin 36. It is mounted to be stationaly, and is preferably fabricated of stainless steel, but may also be constructed of other biocomp~tihle materials, such as plastic. The pin 36 pl~rel~ly iS tubular, and the hub H of the knock-out pin serves as a secondary vacuum port which supplies the vacuum through the needle 20 and inner cutter 22. Surprisingly, Applicants have found that it is important to a~r~liately si~ the knock-out pin to n~ il"i~ clogging problems. For this reason, it has been found that, for the preferred embodiment where the inner ~ m~t~r of the outer piercing needle 20 is approximately .074 inches and the inner ~i~m~t~r of the inner cutter 22 is ~ ~lely .063 inches, the effective tli~mPt~r of the knock-out tube 36, m~ning the cross-sectional area of the tube, should be at least a~ oxin~l~ly .030 inches. Preferably, the effective tli~mPt~
of the knock-out tube is about .045 inches.
The biopsy instrument housing 14 contains the driving mPrh~ni~ and controls for operating the needle assembly 18, and may be mounted in a stationary fashion on a base 37. This base 37 may be an integral part of the housing 14 and is preferably desi~ned to mate with an I-bearn rail of a stereotactic im~in~ unit, but may be modified and tle~i~ to match and mate with any of the various im~in~

CA 022ll422 l997-08-08 W 096124289 PCTnUS96/01655 units available in the industry. The driving m~ for the illustrated preferred embodiment include a long spur gear 38 and a cutter drive gear 40, which is housed within a pinion housing 42 and is rotatably and drivingly ~tt~h~Cl to the inner cutter 22 within the housing 14. In order to rotate or oscillate the cutter 22, the gear 38 is S rotated by a driving motor or stepper motor (not shown). Rotation or oscillation of the gear 38 in turn drives the gear 40 to rotate or oscillate, thereby rotating or oscillating the cutter 22.
In addition to rotation or oscillation, the cutter 22 may also be driven to travel axially, both distally and proximally. A slide handle 44, which is ~ ch~l along with the pinion housing 42 to a slide (not shown), may be ~ t~ by an operator in either direction, as illustrated by the arrow 46, to drive the pinion housing 42 axially. Since the cutter 22 is fixedly ~tt~ ~,~ to the pinion gear 40, which in turn is contained within the pinion housing 42, the cutter follows the axial travel of the pinion housing, p~"~iL~ the operator to advance or retract the cutter, as desired.
A piercing m~h~ni~m or linear ~etll~tr)r 47, located distally of a partition 48 in the housing 14, functions to rapidly advance the entire needle assembly 18 distally in order to locate the tip of the outer piercing needle 20 at the site from which one or more tissue samples are desired. The piercing me~ ni~m ~l~rel~ly includes a driving spring (not shown), a carriage assembly 50~ which is attached to a proximal end portion 52 of the tissue ~s~lte housing 24, a cocking lever 54 which operates against a fixed lever 55, a pierce button 56, and a safety button 57. Operation of the piercing m~ll~nism is described in greater detail hereinbelow.
Of course, the illustrated embodiment is just one of many possible ways to drive and control an ~lltt)m~tic core biopsy device of the type shown and described.
For example, the control system could be an integral part of the computer system in the stereotactic or other im~ing device used to guide the biopsy device, so that the stereotactic device computer would be used to control the cutter, the angular and long~ n~l position of the piercing needle 20, and the knock-out tube position.

CA 022ll422 l997-08-08 Additionally, ~ ll driving m~ s could be employed, such as substit~lting a friction drive for the long spur gear drive. In some in~t~n~s it may be preferred to be able to rotatably and linearly drive and control the hollow outer piercing needle and the knock-out pin, as well as the inner cutter, as disclosed in co-pending application SN 08/217,246, or to employ one of the other needle assembly or needle assembly driving arr~ng~m~r t embo~lim~t~ disclosed therein. Of course, any of the embo~ -r.ll~ disclosed in that application may also be used in conjunction with the inventions herein disclosed.
In operation, as described in the nf~lc~ ioned co-pending application and with particular reference to Figs. 2, 3, and 8 through 13, in addition to Figs. 1, 4, and 5, the point 58 of the needle 20 is first moved into position to pierce the lesion or selected tissue which is to be sampled (Figs. 2 and 3). The initial global position of the point 58 with respect to the tissue area being sampled is det~rmin~cl by the overall position of the biopsy instrument 10 with respect to the patient. For example, the biopsy instrument 10 may be mounted on a commercially available stereotactic guidance system (not shown), comm-)nly used in the medical field for accurate positioning of a variety of medical devices with respect to a patient and with respect to a lesion within a patient. A detailed description of such a motorized biopsy needle positioner, i.e. a stereotactic g~ n~ system, is given in U.S. Patent No. 5,240,011, issued on August 31, 1993, to M~chael Assa, which is hereby incorporated herein by reference. The suspect lesion 59 within the tissue to be sampled is targeted according to the instructions provided with the stereotactic guidance system. The stereotactic gl~ n~e system will enable an ~ ol to advance the point 58 until it is ~ cPnt the specific lesion region 59 to be sampled, as illustrated in Fig. 2.
Once the point 58 is ~c~jac~nt to the specific lesion region to be sampled, finetuning of the location of the point 59 within the tissue sample is preferably accomplished by ~ ting the linear actuator 47 to thereby advance and retract thehollow outer piercing needle 20 along its axis (the actuator 47 may, however, be used wo 96/24289 PCTIUS96101655 for rapid piercing as well). ~hile the linear ~ t~r 47 illustrated in Fig 1, which uses a potential energy device (spring), is pl~r~l,ed, any of a variety of devices capable of inrillcing linear motion may be employed~ inrlutling solenoids, pnt~llm~tic cylinders, or potential energy devices such as springs, motors, or the like. In 5 operation of the ~l~f~l~d embodiment, the cocking lever 54 is pulled ~ ally against the fixed lever 55 to COlll~lc;S~; the spring and cock the c~rri~ assembly 50 in its proximal position, as shown in Fig. 2. Then, when the needle 20 is position~1 outside the lesion, as illustrated in Fig. 2, the pierce button 56 is depressed, releasing the c~ e housing 50 so that the spring uncoils, forcing it rapidly in the direction of 10 the arrow A (Fig. 3), such that the point 58 of the needle pierces the lesion S9.
rely, this procedure could be automated, using a needle control unit to send signals to the line~r ~ tor, which, in turn, would advance and retract the hollow outer piercing needle 20 along its axis.
Now with particular reference to Figs. 8-13, as seen in Fig 8, the needle 20 is 15 ~l~f~l~ly advanced into the lesion 59 with the inner cutter 22 in its fully advanced position to close off the tissue receiving port 28, thus preventing ~n~ing and tearing of the tissue during slow linear movement of the needle 20. Af'cer the hollow outer piercing needle 20 has been positioned at the precise location within the lesion 59 at which it is desired to obtain a tissue sample, a vacuum source is ~c~hl~te(l to apply a 20 vacuum to the vacuum connection 32 in the tissue cassette housing 24 through the vacuum tube 34 (Fig. 1) as the cutter is retracted proximally (Figs. 9 and 10). As a result, a region of low pressure is generated within the hollow outer pien~îng needle 20 in the vicinity of the tissue receiving port 28, and through the vacuum lumen 35.
This facilitates the prolapse of tissue immr~ tely ~ r,ent to the tissue receiving port 25 28 into the interior of the hollow outer piercing needle 20.
Once the tissue is fully prolapsed into the tissue receiving port, as shown in Fig. 10, the prolapsed tissue sample 60 is severed from the main tissue mass by the advancement of the c~nmll~r inner cutter 22 (Fig. 11). The adv~nrt-m~nt of the inner cutter 22 is achieved by advancing the slide knob 44 ~tt~ll~ to the pinion housing 42, thus advancing the inner cutter 22 along its axis within the hollow outer piercing needle 20 past the tissue receiving port 28, to thereby sever the prolapsed tissue sample from the main tissue mass. After being severed from the tissue mass, the S tissue sample is packed into the inner cutter as it moves rol~v~d against the needle pin 61 and rests inside the inner cutter 22. The inner cutter 22, c~ ;";l~g the tissue sarnple 60, is then withdrawn by retracting the slide knob 44 (Fig. 12). The tissue sample is held in the inner cutter 22 as it is withdrawn ~foxilllally toward the tissue c~eeette housing 24 by friction with the inner walls of the ~nn~ Suction createdby the vacuum source can also be used to retain the sample.
As the inner cutter 22 is withdrawn through the tissue c~esette housing 24, the tissue sample 60 is deposited into the tissue cassette 26 by means of the tubular knock-out pin 36, the distal end of which stops the tissue sample within one of the tissue c~ nt chambers 62 (Fig. 1), as is more fully described in the related application SN 08/217,246. Once the tissue r~ette 26 is filled with tissue samples, it may be removed from the tissue r~ett~ housing 24 and transported to a laboratory for analysis, without the n~c~ity of h~n~lling the sarnples. If additional sarnples are desired, a new tissue c~s~tte 26 may be imm~Ai~tely inserted into the tissue ç~ette housing 24 and the collection of samples may continue.
Refe~ing now to Fig. 4, the needle assembly 18 of Fig. 1 is illustrated in greater detail. Significantly, the preferred embodiment of the needle assembly comprises a two-piece body, including the hollow outer piercing needle 20, with its inner cutter 22 and knock-out pin 36, and the tissue cassette housing 24. The fi~une of the tissue r~ett~ housing 24 (excluding the cassette 26) is pl~r.,~ ly molded from a single piece of plastic. If clear plastic is used, an additional advantage is the r~ lt~nt ability to view the collected tissue specimens in the r~sette7 which islocated in a cassette port P in the housing 24 during operation of the device.
Magnification of the specimen is obtained by molding the top surface of the housing WO 96/24289 ~ PCTIUS96/01655 24 to be convex, while the inner surface is s7lhst~nti~11y flat. The ~l~r.,ll~d one-piece plastic cassette housing 24 includes a shaft portion 63, which provides a conduit for holding the cutter 22 and the knockout pin 36, and the ~ ximal end portion 52, which in turn is adapted to be mounted on a post 64 within the housing 14 (Fig 1), forming a part of the r~7n~7~ ~sembly 50. This portion of the c~sse7te housing thus provides the support for the entire cantilevered needle assembly 18.
Yet another advantageous feature of the prefe red needle assembly 18 is the thumbwheel 30. The needle 20 is glued or otherwise securely attached to the thumbwheel, which is then snapped into the housing 24. (~rings 65 fluidly seal the interface between the housing 24 and the thumbwheel 30, in order to preserve thevacuurn between the port 32 and the vacuurn lurnen 35 while simlllt:~neously p~. " ~;LI ;"~ rotation of the thumbwheel relative to the fixed housing 24. Because of this inventive feature, the vacuurn may be c~lmm1micated to the needle 20 from the vacuurn port 32 in the housing 24 no matter what the orientation of the needle is, without the problem som~tim~ encountered in prior embo.li"~"l~ wherein the vacuum tube 34 wraps about the housing 24 as it rotates with the needle 20. The ability to keep the ~ ~e housing 24 stationary solves this hose wrap problem.
Figs. 14-17 illustrate a procedure enabled by the thumbwheel 30, whereby four tissue samples 60 may be acquired from four di~lell~ angular positions and deposited in the sample cassette 26 without removing the hollow outer piercing needle 20 and the tissue receiving port 28 from the lesion 59. Furthermore, th~ integrity of each sample may be preserved and a record of the location from which each of the foursamples is acquired may be created by storing the samples in individual sample co"~ ,Pnt chambers 62 (Fig. 1). Fig. 14 is a cross-sectional view along lines 14-14 of Fig. 10, which illu~ les ~,e~lions for the taking of a first sample 60 ~Fig. 11) with the needle 20 and associated vacuum lumen 35 angularly oriented so that thetissue receiving port is in an upright position within the lesion 59. Fig. 15 is a cross-sectional view along lines 15-15 of Fig. 12, wherein the needle 20 is angularly oriented in the same position as in Fig. 14, aflcer the tissue sample has been removed.
Ihe void 66 represents the location from which the sample was taken. Fig 16 shows the needle assembly as illustrated in Figs. 14 and 15, but where the thumbwheel 30 (Fig. 4) has been used to rotate the needle 20 a~ro~ ~Lely 90 degrees counterclockwise. A second sample is to be taken from this angular location.
Finally, Fig. 17 is yet another similar view, wherein the needle 20 has been rotated by the thumbwheel 30 ~ oxin~lely 300 degrees counterclockwise from the original orientation shown in Figs. 14 and 15 (it should, however, be noted that the invention permits samples to be taken from any angular orientation between 0 and360 degrees). A sample has already been taken from this orientation, ~ well ~ from the 180 degree orientation, so that the void 66 now extends entirely about the needle assembly and four tissue samples have been removed.
Now with reference to Figs. 18 and 19, a modified embodiment of a portion of the needle ~sembly 18 of Figs. 1, 4, and 5 is illustrated, wherein like elements are ~l~sign~tecl with like reference numerals, followed by the letter a. This needleassembly embodiment may be used in conjunction with a vacuum which is drawn through the cutter lumen 23a, and particularly in a procedure where the physician wishes to obtain only a single sample and wants to retain the tissue sample in the tissue receiving port 28a for retrieval (i.e. a "single-core" procedure).
,~tt~ to the ~o~nlal end of the needle point 58a is a distal tip 66 of a tissue stop or wire ~sembly 67, which comprises a wire 68 which is integral with and extends proximally of the tip 66. The ~tt~c~lm~nt of the point 58a to the tip 66 is preferably made by brazing, though other equivalent known ~ mt-nt methods may be used ~ well. The wire 68 extends beneath the entire axial length of the tissue receiving port 28a. Proximally of the tissue receiving port 28a, and near the proximal end of the wire 68, is a corkscrew portion 69, which h~ a ~ m~t~r or cross-sectional width just slightly less than the internal ~ ter of the inner cutter 22a, as illustrated in Fig. 19.

Wo 96/24289 PCTJUS96~01655 In operation, with the cutter 22a withdrawn proximally from the region of the tissue receiving port 28a, the wire ~sembly 67 is st~ti~m~ry in the lumen of thehollow outer piercing needle 20a With the needle in position in the tissue to besampled, a vacuum is drawn through the cutter lumen 23a and the needle lumen, thereby prolapsing tissue into the tissue receiving bowl 28a. A potential problem is that such tissue will prolapse all the way to the bottom of the bowl at a proxirnal region of the bowl, thereby cutting off the vacuum distally of the blocking portion.
Without the vacuum, the distal portion of the bowl may not receive a full volume of prolapsed tissue, thereby causing the tissue sample, when cut, to be only a partial sample. However, the wire 68 functions to hold the prolapsed tissue in an elevated position above the bottom of the bowl, thereby preventing blockage of the lumen.This permits the vacuum to be ~ s~ ed all the way to the tip 66 so that a full-volume sample is assured.
Once the prolapsed tissue sample has been received, and cut off by the inner cutter 22a, the corkscrew portion 69 functions to prevent the sample ~om being sucked or pulled out of the bowl 28a during withdrawal of the cutter. Then~ after the needle is withdrawn from the patient's body and the cutter 22a is withdrawn from the bowl 28a, the tissue sample remains in the bowl and may be retrieved dir~ctly from the bowl by the physician or an ~ t~nt In one yr~r~l~d embodiment, the inner diameter of the hollow outer piercing needle 20a was .074 inches, and the inner fii~mPt~r of the inner cutter 22a was .063 inches. The ~ m~t~r of the wire 68 was .014 inches, and the (li~m~t~ or cross-sectional width of the corkscrew portion 69 was .060 inches. Of course, many other tiim~n.~ions may be utilized as well. Additionally, while a corkscrew configuration is yr~;fcllcd, many other configurations may be employed, as long as they function to prevent ylvxilllal migration of the tissue sample, especially during withdrawal of the cutter. For example, a simple kink in the wire may be used, instead.

Now with particular reference to Figs. 5 and 6, the distal portion of the needleassembly illustrated in Figs. 1 and 4 is shown in perspective and in cross-section, respectively. Two particular features not previously discussed are of note. First, in this particular embo-lim~nt two pl~r~l~bly round vacuum ports 70 com~ nicate bet~veen the tissue receiving port 28 and the vacuum lurnen 35. The distal port 70 is located distally of the tissue receiving port opening, so that it lies just p~ ally of the point 58 and beneath overhang portion 71 of the needle 20. In the plcr~ d embodiment, it has a (li~m~t~r of a~lv~ill~Lely .042 inches. The proximal port 70, on the other hand is signifir~ntly smaller, pl~r~ldl)ly about one-half the ~ r of the larger port (a~lox~ Lely .020 inches), and lies directly beneath the tissue receiving port 28.
The second feature of note is related to how the needle point is ground for sharpening. As illustrated in Fig. 5, it is ~lcr~l,cd that the point be ground to form a plurality of facets 72 (~l~r~,~ly three) wherein no two facets axially intersect within the circ~ lial arc defined by the tissue receiving port 28. Thus, the needle point 58 defines a relatively flat surface on its upper side, as illustrated. This is advantageous in that the flat top surface 72 lifts the tissue upwardly and l~ereby assists its entry into the tissue receiving port 28. On the other h~nd, if two of the facets 72 axially intersect within the arc defined by the tissue receiving port, the tissue often tends to split, potentially degrading the sample quality.
Referring now to Fig 20, a modified embodiment of the needle assembly 18 illustrated in Fig. 6 is shown, wherein like elements are rl('Si~ t~l by like reference numerals, followed by the letter b. The primary ~lirr~lcnce between this embodiment and that of Fig. 6 is the employment of a greater number of vacuum ports 70b, ~l~r~l~ly eight~ between the vacuum lumen 35b and the tissue receiving port 28b. In this embo~limt-nt preferably each of the ports 70b is round and has a fli~mt t~r of ~L~ly .042 inches. Also, in this embodiment all of the ports are located WO 96/24289 PCTIUSg610165 beneath the opening of the tissue receiving port, as illustrated. None lie beneath the overh~ng portion 71b.
The reason for the two di~,lcllL vacuum port configurations in Figs. 6 and 20 is that each has advantages over the other when sarnpling c~tain types of tissue. For S example, in relatively fatty tissue, the eight hole embodiment illustrated in Fig 20 rnay have a greater tendency to clog. Clogging som~tim~ occurs when numerous samples are being taken because, as tissue is received into the tissue receiving port, the vacuum drawn through the vacuum ports 70b tends to draw tissue past the ports and into the vacuurn lumen 35b. Then, when the cutter 22b advances to sever the tissue sample, small pieces of tissue within the vacuum ports fall into the vacuum lumen 35b. Over many sampling cycles, the tissue buildup in the vacuum lurnen 35b partially blocks the vacuum to the distal ports, causing an uneven and ~limini~hed overall vacuum pressure and thereby re~ ing the quality of the tissue samples being obtained. The two-port embodiment illustrated in Fig 6 avoids this problem, because the single small port subject to contact with the tissue sample prolapsing into the tissue receiving port is so small that even if tissue does fall into the vacu~lm lumen from this port, it does not build into a rnass sufficient to cause a blockage. The distal port, on the other hand, is protected by the overhang 71 from contact with the tissue, so no tissue can become caught in the port to create clogging.
When relatively hard tissue is being sampled, in contrast, the eight-port embodiment shown in Fig. 20 rnay be pl~r~l~ule. This is because hard tissue is less pliable, and therefore generally requires a more evenly distributed vacuum pressure to draw it fully into the tissue reoeiving port. Obviously, the higher number of evenly spaced ports in the Fig. 20 embodiment will provide this n~ ry drawing pressure.Furthermore, hard tissue is much less likely to actually be drawn into the vacuurn ports 70b, so clogging is not a likely issue.
Fig. 21 illustrates a further modified embodiment of the needle assembly 18 illustrated in Fig. 6, wherein like elements are designated by like reference numerals, followed by the letter c. The difference between the Figs. 6, 20, and 21 emboAimPnts is that in Fig. 21, the vacuum ports 70c are arranged at an angle cc with respect to the transverse axis 80 of the needle assembly 18c. Additionally, the side w~lls 82 of the tissue receiving port 28c are pl~r~l~ly arranged at substantially the same angle a In S the pl~r~led embodiment, the angle oc is a~roxill~lely 15-75 degrees. This angled oriPnt~tion is advantageous because it permits the cutter 22c (not shown in Fig. 21) to traverse the vacuum ports 70c and side walls 82 of the tissue receiving port 28c more easily and Illillillli:~r~ damage to the cutter blade due to i~ lr~lillg contact with these edges.
Yet another modified embodiment of the needle assembly embodiment illustrated in Fig. 6 is shown in Fig. 22. In this embodiment, like elements aredesignated by like reference numerals, followed by the letter d.
The Fig. 22 embodiment is ~lPsign~ to assist in solving the clogging problem discussed with respect to the Figs. 6 and 20 embo~limPnts and snm~timP~s encountered 15 during the process of collecting a number of tissue samples from a patient during a single procedure. As previously Aiscl~sseA, the problem is that bits of tissue, blood, and other biological debris will, over time, become ~lPt~hP~l from the tissue samples being collected and become lodged in the tissue receiving port 28d, vacuum ports70d~ or in one of the lumens 23d or 35d. Since the vacuum ports 70d are relatively 20 small, the problem of clogging those ports is most acute, as the resultant reduced vacuum in the tissue receiving port 28d may cause the collection of partial tissue samples. Conseqll~ntly, as illustrated in Fig. 22, a flush port 84 may be located between the vacuum lumen 35d and the piercing needle lumen, similar to vacuum ports 70d but located distally of the closed (most advanced) position of the cutter ~d.
25 Then, when the cutter 22d is in the closed position, as illustrated, a pressu~zed saline solution may be permitted to flow through the cutter lumen 23d into the needle lumen distally of ~e cutter, then through the flush port 84 as shown by the arrow 86, and finally returned to its source through the vacuum lumen 35d. This procedure clears any ~cllmlll~t~A debris and thus helps to ensure that the tissue samples are as complete as possible. A safety feature prevents saline from being injected through the system when the cutter is not in a fully closed position; i.e. completely blocking the tissue receiving port 28d.
As illustrated in Fig 23, a problem som~tim~ s encountered during operation of the biopsy device 10 (Fig. 1) is that the tissue sample 60 being pulled into the tissue receiving port or bowl 28 may have a tendency to bind as the reiatively large cross-section of tissue is necked down into the space between the rotating cutter 22 and the needle 20. This problem is worsened because of the possible rotation of the cutter 22 relative to the stationary needle 20. In Fig 24, a solution to this problem is illustrated, wherein the cutter 22e is modified to comprise a relatively short blade portion 90, and a non-rotating sleeve 92, ~l~r~,~ly cu~ lg a polyamide or a similar low-friction material or coating, surrounds the retn~in-~ of the cutter and trAn~l~tt-.s axially with it. The sleeve thus acts as an anti-tissue Wld~)lllg bearing, thereby helpinp to prevent tissue binding, and as a bearing to the cutter.
Fig. 25 illustrates a known prior art single-use biopsy device as disclosed in U.S. Patents No. 4,699,154 and Re. 34,056, both previously incorporated herein by refierence. It should be noted that this embodiment is merely reprt-s~nt~tive of many el~ types of such devices currently or potentially available, any of which wouldbe suitably used in conjunction with the inventive embotlim~nt~. Howe-.~er, the illustrated embodiment is illustrative and will serve as a good point of reference.
In the device 94, a needle assembly 96 comprises a hollow outer cutting r~nmll~ or needle 98 and an inner piercing needle 100. The needles 98 and 100 are pointed at their distal end~ and the inner needle 100 is also provided with a tissue receiving notch 102 at its distal end for receiving the tissue sample. At their ~r~ al ends, the needles 98 and 100 are provided with heads 104 and 106, respectively, for mounting within the housing 108 of the sampling device. A front slide 110 and a rear slide 112 are slidably provided along the axial direction of the housing 108.

CA 022ll422 l997-08-08 W 096/24289 PCTrUS96/0165S

Each slide 110 and 112, respectively, is ~ t~ by at least one spring 114 and 116, respectively, biasing the respective slide in a distal direction. The spring 114 acts between a stop 118 provided on the slide 110 and a f~xed transverse wall (not shown) in the housing 108. The spring 116 acts between a stop on the slide 112 and the rear S end wall 120 of the housing 108. In the housing 108, there are two parallel slide bars or guide rods 122, 124 on which the slides 110, 112 run.
The front slide 110 may be retained in a p~ ally withdrawn position by means of a hook provided on a tongue member 126 protruding from the slide, the tongue member Pn~ging the bottom edge of the ~rc~lcl-lcllLioned transverse wall (not shown). The rear slide 112 may in a corresponding way be hooked and retained in a withdrawn position by means of a hook 128 protruding from the slide, which in turn engages a springy hook member 13Q at the rear wall 120 of the housing The tissue sampling device 94 is loaded and released in the following manner.
In the unloaded initial position, the slides 110, 112 are each biased distally (toward the left) by the springs 114, 116, respectively. To load the device, the needle assembly 96, in which the inner needle 100 is freely slidable in the hollow outer c~nn~ 98, is moved ~loxill ally (to the right) and placed in the correct position in the housing 108, so that the needle heads are engaged into the slides 110, 112, which are configured to receive them, such that each needle head 104, 106 foll(>ws themovements of the slides 110, 112, respectively.
Thus, when the needle assembly 96 has been placed in the device, the device is energi7ed in that the slides 110, 112 are moved ~im-llt~n~ously to their latched positions, whereby the springs 114, 116 are cunl~ ed and would act to return theslides 110, 112 to their initial position if released from the l~t~hing hooks 126, 128, and 130.
When the needle ~sembly 96 h~ been positioned at the desired tissue location, the sampling is carried out by pressing a release button 132, whereby the engagement between the hooks 128 and 130 is interrupted. Because of the bi~ed spring 116, the slide 112 together with the inner needle 100 is thus pushed distally toward the left to its initial position. For a short period of time, the slide 110, together with the outer c~nmll~ 98, is still retained in its energized position. Thus, the inner piercing needle 100 protrudes from the outer c~nmll~ 98, thereby exposing the S notch 102. Tmm~ t~ly afl[er having reached its initial position, however, the slide 112 impacts and abuts the hook spring (tongue member) 126, and intern1pts the Pn~Pm~ nt of the hook with the transverse wall (not shown), whereby the spring 114 also pushes back the slide 110 distally to its initial position. Consequently, the outer c~nnlll~ 98 again is pushed over the side facing notch 102 in the inner needle 100, thereby severing the tissue sample that has prolapsed into the notch. Thel~lel the needle assembly 96 is withdrawn from the tissue and removed from the sampling device, following which the sample is analyzed.
While such a device works fairly well for its int~n~l~l purposes, as discussed in the Background of the Invention, there are a number of problems inherent in their operation. Most significantly, there is no positive means for en~in~g the tissuesample within the notch 102, particularly since no source of vacuum is available, as in the embo-lim~nt~ of Figs. 1-24, to assist in collection of the tissue. Con~ ntly, several inventive emborlim~ntc including mP~nical elements for capturil~g the tissue are disclosed herein, each of which dramatically improve the quality and quantity of the tissue samples collected, on a c(.~ basis.
Referring now to Figs. 26-28, a modified embodirnent of the needle assembly 96 of Fig. 25 is illustrated, wherein like elements are designated by like reference numerals. followed by an a. In this embodiment, in their initial position, as shown in Fig. 26, uith both springs energized, the inner needle lOOa is retracted within the outer c~nmll~ 98a, and cutter le~flets 134 are in a closed position on the distal end of the needle 98a. Preferably, there are two, four, or six cutter leaflets 134, which in the closed position come together to form a piercing cone. Of course, however, any number of leaflets may be employed within the scope of the invention.

Fig. 27 illustrates the int~m~ te position immediately after the release button 132 (Fig. 25) has been activated. At this juncture, the spring 116 propels the inner needle lOOa distally, forcing the leaflets 134 open. The sharpened distal edges 136 of the needle lOOa begin to cut tissue, which is c~ nt~in~ within the distal end portion of S the needle 100a Then, upon release of the spring 114, the outer c~nm~l~ 98a is propelled distally, as shown in Fig. 28, causing the leaflets 134 to snap closed to sever and contain the tissue sample 138.
It should be noted that this embotlimPnt, while useful as a modification to the Fig 25 device, may also be employed in the Fig. 1 device. In this in~t~n~ the inner needle lOOa comprises a rotating cutter, which tr~n~l~tçs back and forth as previously described.
Figs. 29 and 30 illustrate a second modified embodiment of the needle assembly in the Fig. 25 device. Again, like elements are designated by like reference numerals, followed by a b. In this embo-lim~nt the inner needle lOOb has been modified to include an "alligator" tip 140, which includes jaws 142, 144 and teeth 146. When the spring 116 is released, the inner needle lOOb shoots distally and captures tissue in the opening 148 within the jaws 142, 144. Then, when the spring 114 is released, the outer c~nmll~ 98b shoots distally, severing tissue along the sides of the tissue sample opening 148 as it moves distally, and also forcing the jaws 142, 144 shut, so that they "bite off' the end of the tissue sample 138b, as illustrated in Fig. 30. This embodiment also may be adapted for use with the device of Fig. 1, if desired.
Finally, Figs. 31-34 illustrate a third modified embodiment of the needle assembly in the Fig. 25 device. In this embo~lim~nt like elements are designated by like reference numerals, followed by a c. Like the Fig. 29 embodiment, the innerneedle or "grabber" lOOc has been modified, this time to include a plurality of hooked extractors 150 e~t~ntling from its distal end. The outer c~nm-l~ 98c includes a sharpened cutter point 152. In operation, initially the grabber lOOc is retracted into WO 96124289 PCT~IJS96101655 the cutter 98c while the device is in its energi~d state, the point 152 being used to pierce the body wall 154 as ~e device is guided to the desired tissue sample 138c (Fig. 32). Then, as illustrated in Fig. 33, the grabber lOOc is shot distally by means of the release of spring 116. As it travels distally, the hooked extract~s 150 become S ~.~r.n~l~l and latch onto the tissue sample 138c. Then, once the second spring 114 is released, the cutter 98c shoots distally, coll~psin~ the hooked extractors 150 and severing the tissue sample, which is received into the lumen of the cutter 98c.
This embo~lim~nt~ as well, may be adapted for use with the device illustrated in Fig 1. Furth~m- re, while four e~ractors 150 are shown, in actuali~ any desired 10 number may be employed, as long as they may be fully retracted within the cutter 98c.
While this invention has been described with respect to various specific examples and embo.~ , it is to be understood that the invention is not limited thereto and that it can be variously practiced within the scope of the following claims.

Claims

WHAT IS CLAIMED IS:

1. A biopsy instrument comprising:
a housing; and a needle assembly, said needle assembly comprising a tubular piercing member having a distal pointed end, and a laterally positioned tissue receiving port proximate to said distal pointed end which opens into a tissue sample chamber, wherein said tubular piercing member is rotatably attached to said housing and held in an axially fixed position within a tissue mass;
a cannular cutting member adapted to coact with said tubular piercing member to cut a tissue sample from the tissue mass such that the tissue sample can be transported to a proximate end of said tubular piercing member by the cutting member as it is withdrawn proximally along said tubular piercing member; and an elongate knock-out pin disposed coaxially within said tubular piercing member and said cannular cutting member and being adapted to dislodge said tissue sample from the cutting member at a predetermined location as the cutting member is withdrawn.

2. A biopsy instrument as recited in claim 1, wherein said knock-out pin has an effective diameter of at least .030 inches.

3. A biopsy instrument as recited in claim 1, wherein said knock-out pin has an effective diameter of approximately .045 inches.

4. A biopsy instrument as recited in claim 1, wherein the ratio of the effective diameter of said knock-out pin to the internal diameter of said cannular cutter is at least approximately one-half.

5. A biopsy instrument as recited in claim 1, wherein said tubular piercing member comprises an elongate outer piercing needle and said cannular cutting member comprises an elongate inner cannula disposed coaxially and slidably within said elongate outer piercing needle, said elongate inner cannula having a sharpened distal end for cutting a portion of tissue protruding into said elongate outer piercing needle tissue receiving port when said elongate inner cannula slides past said port, thereby depositing the portion of cut tissue within said elongate inner cannula proximal to said sharpened distal end.

6. A biopsy instrument as recited in claim 5, wherein said needle assembly further comprises a tissue cassette housing, said housing including means interconnecting said tissue cassette housing and the hollow outer piercing needle to permit rotation of said outer needle without rotating said tissue cassette housing.

7. A biopsy instrument as recited in claim 6, wherein said interconnecting means comprises a thumbwheel.

8. A biopsy instrument as recited in claim 5, wherein said tissue cassette housing is fabricated molded plastic.

9. A biopsy instrument as recited in claim 8, wherein said plastic is transparent, in order to permit viewing of tissue samples contained therein.

10. A biopsy instrument as recited in claim 5, said needle assembly further comprising a vacuum lumen disposed beneath said outer piercing needle and at least one fluid communication port between said vacuum lumen and said tissue sample chamber for communicating a vacuum pressure from said vacuum lumen to said tissue sample chamber.

11. A biopsy instrument as recited in claim 10, wherein said at least one fluid communication port comprises a plurality of holes of substantially equal size, all of which are disposed directly beneath said tissue receiving port.

12. A biopsy instrument as recited in claim 10, wherein said at least one fluid communication port comprises a first relatively small hole disposed directly beneath said tissue receiving port and a second relatively large hole disposed distally of said tissue receiving port so that it is shielded by an overhang comprising a portion of the outer cylindrical wall of the hollow outer piercing needle distally of the tissue receiving port.

13. A biopsy instrument as recited in claim 10, said needle assembly having a transverse axis and said at least one fluid communication port comprising a plurality of slots oriented at an angle a with respect to said transverse axis.

14. A biopsy instrument as recited in claim 13, wherein the transverse edges of said tissue receiving port are oriented at said angle a with respect to said transverse axis.

15. A biopsy instrument as recited in claim 14, wherein said angle .alpha. is within a range of 15-75 degrees.

16. A biopsy instrument as recited in claim 10, wherein said inner cannula may be advanced distally a sufficient distance to completely close off said tissue receiving port, said at least one fluid communication port comprising a port disposed distally of the distal end of the inner cannula when the inner cannula is in its fully advanced position, said port being adapted for use in flushing the needle assembly of excess material using pressurized fluid.

17. A biopsy instrument as recited in claim 1, wherein said needle assembly further comprises a non-rotatable bearing sleeve disposed about said cutting member.

18. A biopsy instrument, comprising:
an elongate hollow outer piercing needle having a lumen, a sharpened distal end for piercing tissue, and a lateral opening located proximal to said spharpened distal end for receiving a portion of a tissue mass positioned adjacent to said lateralopening;
an elongate inner cutting cannula having a lumen and being disposed coaxially and slidably within said elongate outer piercing needle, said elongate inner cannula having a sharpened distal end for cutting the portion of tissue protruding into said elongate outer piercing needle lateral opening when said elongate inner cannula slides distally past said lateral opening, thereby depositing the portion of cut tissue within said elongate inner cannula proximal to said sharpened distal end;
a vacuum generator for generating a vacuum pressure which fluidly communicates with said lateral opening through said inner cannula lumen; and a tissue stop device disposed in the lumen of said inner cannula and having a structure disposed proximally of said lateral opening which is adapted to sufficiently obstruct said lumen so that a tissue sample drawn into the lateral opening by said vacuum pressure and severed by the cutting cannula is prevented from migrating proximally through the cutting cannula lumen.

19. A biopsy instrument as recited in claim 18, wherein said tissue stop device comprises a linear wire disposed along said inner cannula lumen from the distal end thereof, the proximal end of the wire being configured to comprise said obstruction structure.

20. A biopsy instrument as recited in claim 19, wherein said obstruction structure comprises a corkscrew portion of said wire, the cross-sectional width of the corkscrew portion being just slightly smaller than the internal diameter of said cutter lumen.

21. A biopsy instrument as recited in claim 19, wherein the distal end of said wire comprises a tip which is fixedly attached to the distal end of the hollow outer piercing needle.

22. A biopsy instrument, comprising:
an outer hollow cannula having a distal end portion which comprises a plurality of leaflets, said leaflets each having a proximal end which is hinged to the outer cannula wall and a distal end, the leaflets being biased to pivot about their hinges to a closed position wherein the distal ends of the leaflets contact one another;
and an inner hollow cannula;
wherein at least one of said cannulas is slidable relative to the other cannula so that first the inner cannula may be extended distally with respect to the outer cannula to force said leaflets to an open position and to cut and contain a tissue sample, and then the outer cannula may be extended distally with respect to the inner cannula sufficiently so that the leaflets clear the inner cannula and snap closed about their hinges, thereby severing said tissue sample and containing it within the inner cannula.

23. A biopsy instrument, comprising:
an outer hollow cannula having a sharpened distal end portion; and an inner hollow cannula having a distal portion which is biased to expand radially at its distal end;

wherein at least one of said cannulas is slidable relative to the other cannula so that first the inner cannula may be extended distally with respect to the outer cannula such that said inner cannula distal portion expands radially to capture a tissue sample, and then the outer cannula may be extended distally with respect to the inner cannula sufficiently so that the distal end portion of the inner cannula is forced by the outer cannula to close about and sever the tissue sample, thereby containing thesample within the inner cannula.

24. A biopsy instrument as recited in claim 23, wherein the distal portion of the inner cannula comprises an alligator tip having a pair of hinged jaws which are biased to expand radially.

25. A biopsy instrument as recited in claim 23, wherein the distal portion of the inner cannula comprises a plurality of hooked extractors.

26. A method of flushing debris from a biopsy instrument comprising an elongate outer piercing needle having a laterally positioned tissue receiving port which opens into a tissue sample chamber in a lumen of the outer piercing needle, and an elongate inner cutting cannula having an axial lumen, a sharpened distal end and being disposed coaxially and slidably within said elongate outer piercing needle, said inner cannula being capable of advancement distally to a position wherein the tissue receiving port is completely closed off, said needle assembly comprising a vacuum lumen disposed beneath said tissue receiving port and further comprising at least one fluid communication port disposed distally of the distal end of the elongate inner cannula when the inner cannula is in its fully advanced position, said method comprising the steps of:
a) advancing the inner cannula so that it extends distally sufficiently to completely close off the tissue receiving port; and b) injecting a pressurized fluid through one of said inner cannula and said vacuum lumens, so that the fluid flows through the fluid communication port and into the other one of said two lumens, from which the fluid returns to its source, thereby flushing accumulated debris from the biopsy instrument.