U.S. patent application number 10/126218 was filed with the patent office on 2002-08-29 for methods and devices for automated biopsy and collection of soft tissue.
Invention is credited to Burbank, Fred H., Galt, Kenneth M., Ritchart, Mark A., Stuart, J. Michael.
Application Number | 20020120212 10/126218 |
Document ID | / |
Family ID | 23527740 |
Filed Date | 2002-08-29 |
United States Patent
Application |
20020120212 |
Kind Code |
A1 |
Ritchart, Mark A. ; et
al. |
August 29, 2002 |
Methods and devices for automated biopsy and collection of soft
tissue
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.
Inventors: |
Ritchart, Mark A.;
(Murrieta, CA) ; Stuart, J. Michael; (Lake Forest,
CA) ; Burbank, Fred H.; (San Juan Capistrano, CA)
; Galt, Kenneth M.; (Seal Beach, CA) |
Correspondence
Address: |
AUDLEY A. CIAMPORCERO JR.
JOHNSON & JOHNSON
ONE JOHNSON & JOHNSON PLAZA
NEW BRUNSWICK
NJ
08933-7003
US
|
Family ID: |
23527740 |
Appl. No.: |
10/126218 |
Filed: |
April 19, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10126218 |
Apr 19, 2002 |
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09746402 |
Dec 21, 2000 |
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09746402 |
Dec 21, 2000 |
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08825899 |
Apr 2, 1997 |
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08825899 |
Apr 2, 1997 |
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08386941 |
Feb 10, 1995 |
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5649547 |
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08386941 |
Feb 10, 1995 |
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08217246 |
Mar 24, 1994 |
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5526822 |
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Current U.S.
Class: |
600/567 |
Current CPC
Class: |
A61B 2010/0208 20130101;
A61B 8/0841 20130101; A61B 10/0266 20130101; A61B 10/0283 20130101;
A61B 17/221 20130101; A61B 2010/0225 20130101; A61B 6/12 20130101;
A61B 2017/303 20130101; A61B 10/0275 20130101 |
Class at
Publication: |
600/567 |
International
Class: |
A61B 010/00 |
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 as 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 0.030
inches.
3. Ai biopsy instrument as recited in claim 1, wherein said
knock-out pin has an effective diameter of approximately 0.045
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 .alpha. 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 .alpha. 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 sharpened
distal end for receiving a portion of a tissue mass positioned
adjacent to said lateral opening; an elongate inner cutting cannula
having a lumen and being disposed coaxially and slidable 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 position 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 serving 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 caputre 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 the sample 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 is 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.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of co-pending
parent application Ser. No. 08/217,246, filed Mar. 24, 1994.
FIELD OF THE INVENTION
[0002] The present invention relates to methods and devices for
tissue sampling, and more specifically to improved biopsy
instruments and methods for acquiring subcutaneous biopsies and for
removing lesions.
BACKGROUND OF THE INVENTION
[0003] It is often desirable and frequently necessary to sample or
test a portior tissue from humans and other animals, particularly
in the diagnosis and treatment of patients with cancerous tumor,
pre-malignant conditions, and other diseases or disorders.
Typically, in the case of cancer, when the physician establishes by
means of procedures such as palpation, x-ray, or ultrasound imaging
that suspicious circumstances exist, a biopsy is performed to
determine whether the cells are cancerous. Biopsy may be done by an
open or percutaneous technique. Open biopsy, which is an invasive
surgical procedure using a scalpel and involving direct vision of
the target area, removes the entire mass (excisional biopsy) or a
part of the mass (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
imaging 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 examination and may be prepared such as
in a Papanicolaou smear. In core biopsy, as the term suggests, a
core or fragment of tissue is obtained for histologic examination
which may be done via a frozen section or paraffin section.
[0004] The type of biopsy utilized depends in large part on
circumstances present 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 more frequently
by the medical profession.
[0005] Two types of image guided percutaneous core breast biopsy
instruments are presently available. One such instrument is a
spring-powered single-use device, such as the BIOPTY.RTM. gun,
available from C.R. Bard, Inc. Such a gun is shown and described in
U.S. Pat. Nos. 4,699,154 and 4,944,308, as well as in U.S. Reissued
Pat. 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 easy to use.
However, they also have disadvantages. 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 reinsertion of the device. This action is
tedious and time consuming.
[0006] A further disadvantage of such single-use guns is the needle
typically used in such a device, e.g. the True Cut.RTM. needle
manufactured 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 comprises a pointed inner stilette with a side-facing notch to
receive tissue near its distal pointed end and an outer, sharpened
sliding cannula. 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
cannula is rapidly advanced, thereby severing the sample of tissue
contained within the notch. Unfortunately, the True Cut.RTM. needle
is rough on organs and lesions, often only obtaining small
fragments of tissue, and is quite operator dependent--some
individuals are good at operating the device and some are not. It
also is tissue selective, meaning that the piercing stilette and
sliding cutter can "push away" the lesion of interest, particularly
in situations where a relatively large lesion is surrounded by much
softer tissue (i.e. fat).
[0007] The second type of image guided percutaneous core breast
biopsy instrument currently available is a vacuum-assisted
automatic core biopsy device. One such successful biopsy gun is
shown and disclosed in related parent application Ser. No.
08/217,246, filed on Mar. 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, meaning that the device is equally
capable of cutting through hard and soft tissue. The gun also
includes means to direct and position the cutting chamber in
arbitrary positions about and along its longitudinal axis, means
for rapid and atraumatic removal of an arbitrary number of core
samples with only a single needle insertion into the body and
organ, and means for coding and decoding the location from which
the samples were obtained. Together, these capabilities allow for
more complete sampling of large lesions and for the complete
removal of small lesions. This type of instrument has been very
successful in permitting the obtainment of a plurality of tissue
samples from different locations with only a single needle
insertion, as well as in obtaining high quality samples in a manner
which does not require direct handling of the samples by the
operator. However, it does not operate equally well in all
procedures and in all bodily environments. For example, instrument
performance and success often varies dependent upon the type of
body tissue being sampled; i.e. relatively fatty or relatively
hard.
[0008] What is needed then, are innovations for improving 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 operate equally well in all tissue
environments.
SUMMARY OF THE INVENTION
[0009] This invention addresses the aforementioned needs by
providing 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
cassette housing, permitting easy and inexpensive fabrication while
also permitting the handling and viewing of multiple tissue samples
without physical contact by the instrument operator. The housing is
interconnected with the piercing needle using a thumbwheel which
permits the needle-to rotate relative to the housing thereby
preventing the vacuum tube from wrapping about the housing. Several
variant vacuum port embodiments are disclosed, each of which have
advantages in certain tissue environments. Also disclosed is a
method for backflushing biological debris from the instrument which
builds up after repeated sampling procedures, without removing the
instrument from the selected tissue location.
[0010] With respect to the single-use type of biopsy instrument,
several tissue capture embodiments are disclosed for improving the
capture process, so that complete and well preserved samples are
obtained. Many of these embodiments are also applicable for use
with the active capture instrument type.
[0011] 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 includes a tubular piercing
member having a distal pointed end and a laterally positioned
tissue receiving port proximate to the distal pointed end which
opens into a tissue sample chamber. The tubular piercing member is
rotatably attached to the housing and held in an axially fixed
position within a selected tissue mass. The needle assembly further
includes a cannular cutting member adapted to coact with the
tubular piercing member to cut a tissue sample from the tissue
mass. The tissue sample is transported to a proximate end of the
tubular piercing member by the cutting member as it is withdrawn
proximally along the tubular piercing member. An elongate knock-out
pin is disposed coaxially within the tubular piercing member and
the cannular cutting member for the primarily purpose of dislodging
the tissue sample from the cutting member at a predetermined
location as the cutting member is withdrawn.
[0012] Surprisingly, the inventors have found that preferably, in
order to mining tissue clogging of the cutter, the knock-out pin
should have an effective diameter or cross-sectional area of at
least 0.030 inches, and the ratio of the effective diameter of the
knock-out pin to the internal diameter of the cannular cutter
should be at least approximately one-half.
[0013] In another aspect of the invention, a biopsy instrument
includes an elongate hollow outer piercing needle having a lumen, a
sharpened distal end for piercing tissue, and a lateral opening
located proximal to the sharpened distal end for receiving a
portion of a tissue mass positioned adjacent to the lateral
opening. Also included are an elongate inner cutting cannula having
a lumen, which is disposed coaxially and slidably within the outer
piercing needle. The inner cannula has a sharpened distal end for
cutting the portion of tissue protruding into the lateral opening
of the outer piercing needle when the inner cannula slides distally
past the lateral opening. This causes the portion of cut tissue to
be deposited within the inner cannula proximal to the distal end. A
vacuum generator generates a vacuum pressure which fluidly
communicates with the lateral opening through the inner cannula
lumen. In such an embodiment, it is often desirable to prevent the
tissue sample from migrating proximally through the cutting cannula
lumen, so an inventive tissue stop device is disposed in the lumen
of the inner cannula which has a structure, preferably a corkscrew
portion of a linear wire, disposed proximally of the lateral
opening. This structure sufficiently obstructs the lumen so that
the tissue sample cannot migrate proximally past it.
[0014] In yet another aspect of the invention, a biopsy instrument
includes an outer hollow cannula living a distal end portion which
comprises a plurality of leaftlets. Each leaflet has a proximal end
which is hinged to the outer cannula wall and a distal end, and are
each biased to pivot about their hinges to a closed position
wherein the distal ends of the leaflets contact one another. The
instrument further includes an inner hollow cannula, and at least
one of the inner and outer 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 the 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 the
tissue sample and containing it within the inner cannula.
[0015] In a further aspect of the invention, a biopsy instrument
has 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. At least one of the 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 the inner cannula distal portion expands radially to
capture a tissue sample. 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 the sample within the inner cannula. The distal portion
of the inner cannula may comprise, for example, either an alligator
tip having a pair of hinged jaws which are biased to expand
radially, or a plurality of hooked extractors.
[0016] Still another aspect of the invention involves a method for
flushing debris form a biopsy instrument, which includes an outer
piercing needle having a laterally positioned tissue receiving port
which opens into a tissue receiving chamber and an inner cutting
cannula having an axial lumen and a sharpened distal end, which is
disposed 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 further comprises
at least one fluid communication port disposed distally of the
distal end of the inner cannula when the inner cannula is in its
fully advanced position. The inventive method includes the steps of
advancing the inner cannula of the instrument so that it extends
distally sufficiently to completely close off the tissue receiving
port and then injecting a pressurized fluid through one of the
inner cannula and the vacuum lumens, so that the fluid flows
through the fluid communication port and into the other one of the
two lumens, from which the fluid returns to its source, thereby
flushing accumulated debris from the biopsy instrument.
[0017] 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.
BRIEF DESCRIPTION OF THE DRAWING
[0018] FIG. 1 is a perspective view of an automatic core biopsy
device of the type shown and described in co-pending patent
application Ser. No. 08/217,246;
[0019] FIG. 2 is a schematic 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 target lesion;
[0020] FIG. 3 is a schematic plan view similar to FIG. 2, showing
the device after it has penetrated the target lesion, in a position
to begin collecting tissue samples;
[0021] FIG. 4 is a cross-sectional view, from the left side, of the
needle assembly of the device illustrated in FIG. 1;
[0022] FIG. 5 is an enlarged perspective view of the portion of
FIG. 1 delineated by the numeral 5.
[0023] FIG. 6 is a cross-sectional view of one embodiment of the
needle assembly illustrated in FIG. 5;
[0024] FIG.7 is a cross-sectional view taken along lines 7-7 of
FIG. 6;
[0025] FIG. 8 is ad enlarged cross-sectional view taken along lines
8-8 of FIG. 3;
[0026] 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;
[0027] 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 vacuum pressure;
[0028] FIG. 11 is an enlarged cross-sectional view similar to FIG.
8, illustrating the simultaneous rotation and distal advancement of
the cut to cut off a tissue sample;
[0029] FIG. 12 is an enlarged cross-sectional view similar to FIG.
8, illustrating the proximal withdrawal of the cutter with the
tissue sample contained therein;
[0030] FIG. 13 is an enlarged cross-sectional view of the interface
between the proximal end of the tissue cassette and the tissue
cassette housing illustrated in FIG. 4, showing the operation of
the, knock-out pin to retain the tissue sample in the tissue
cassette as the cutter is withdrawn proximally;
[0031] FIG. 14 is a cross-sectional view taken along lines 14-14 of
FIG. 10;
[0032] FIG. 15 is a cross-sectional view taken along lines 15-15 of
FIG. 12;
[0033] FIG. 16 is a cross-sectional view similar to FIG. 14,
wherein the outer needle and inner cutter have been rotated
approximately 90 degrees counterclockwise to take a second tissue
sample;
[0034] FIG. 17 is a cross-sectional view similar to FIG. 15,
wherein the outer needle and inner cutter have been rotated
approximately 300 degrees counterclockwise, and a fourth tissue
sample has been taken;
[0035] FIG. 18 is a cross-sectional view of a second embodiment of
the needle assembly shown in FIG. 3;
[0036] FIG. 19 is a cross-sectional view along lines 19-19 of FIG.
18;
[0037] FIG. 20 is a cross-sectional view of a third embodiment of
the needle assembly shown in FIG. 3;
[0038] FIG. 21 is a top plan schematic view of the tissue receiving
port of a fourth modified needle assembly embodiment;
[0039] FIG. 22 is a cross-sectional view similar to FIG. 3,
illustrating a fifth modified needle assembly embodiment;
[0040] 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 operating
regimes;
[0041] FIG. 24 is a fragmentary cross-sectional view of the cuter
portion of a sixth modified needle assembly embodiment,
illustrating an inventive solution to prevent potential tissue
binding situations like that illustrated in FIG. 23;
[0042] FIG. 25 is a cross-sectional view of a prior art single-use
biopsy device, of the type shown and described in U.S. Pat. No.
4,699,154;
[0043] FIG. 26 is a fragmentary 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;
[0044] FIG. 27 is a fragmentary 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;
[0045] FIG. 28 is a fragmentary cross-sectional view of the needle
assembly illustrated in FIG. 26, showing the needle assembly in a
third position wherein the tissue sample has been severed and is
contained in the tissue receiving port of the needle assembly;
[0046] FIG. 29 is a fragmentary cross-sectional 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 advancement into the selected tissue sample site;
[0047] FIG. 30 is a fragmentary cross-sectional view of the needle
assembly illustrated in FIG. 29, showing the needle assembly in a
second position after capture of a tissue sample;
[0048] FIG. 31 is a schematic exploded view of a third modified
needle assembly for a biopsy gun of the type illustrated in FIG.
25;
[0049] FIG. 32 is a schematic side elevational view of the needle
assembly illustrated in FIG. 31, showing the assembly in a first
position approaching a selected tissue sample;
[0050] FIG. 33 is a schematic side elevational view similar to FIG.
32, illustrating the needle assembly in a second position grabbing
the selected tissue sample; and
[0051] FIG. 34 is a schematic side elevational view similar to FIG.
32, illustrating the needle assembly in a third position after
capture of the selected tissue sample.
DESCRIPTION OF THE INVENTION
[0052] 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 Ser. No. 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 cuter 22
having a lumen 23 (FIG. 5), a tissue cassette housing 24, and a
tissue cassette 26. The hollow outer piercing needle 20 further
includes a tissue receiving port or bowl 28. A thumbwheel 30
interconnects the tissue cassette housing 24 and the hollow outer
piercing needle 20, preferably permitting rotation of the needle 20
without rotating the tissue cassette housing 24, as will be more
completely described hereinbelow. A vacuum port 32 in the tissue
cassette housing 24 is adapted for attachment 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 alternatively
or simultaneously be supplied directly through the lumens of the
hollow outer piercing needle 20 and the inner cutter 22,
respectively, if desired.
[0053] 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 stationary, and is preferably fabricated of
stainless steel, but may also be constructed of other biocompatible
materials, such as plastic. The pin 36 preferably 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
appropriately size the knock-out pin to mini e clogging problems.
For this reason, it has been found that, for the preferred
embodiment where the inner diameter of the outer piercing needle 20
is approximately 0.074 inches and the inner diameter of the inner
cute 22 is approximately 0.063 inches, the effective diameter of
the knock-out tube 36, meaning the cross-sectional area of the
tube, should be at least approximately 0.030 inches. Preferably,
the effective diameter of the knock-out tube is about 0.045
inches.
[0054] The biopsy instrument housing 14 contains the driving
mechanisms 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
designed to mate with an I-beam rail of a stereotactic imaging
unit, but may be modified and designed to match and mate with any
of the various imaging units available in the industry. The driving
mechanisms 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 attached to the
inner cutter 22 within the housing 14. In order to rotate or
oscillate the cutter 22, the gear 38 is 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.
[0055] 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 attached along with the pinion housing 42
to a slide (not shown), may be actuated 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 attached 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, permitting the operator to advance or ret the cutter, as
desired.
[0056] A piercing mechanism or linear actuator 47, located distally
of a partition 48 in the housing 14, functions to rapidly advance
the entire needle assembly 18 distal 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 mechanism preferably
includes a driving spring (not shown), a carriage assembly 50,
which is attached to a proximal end portion 52 of the tissue
cassette 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 mechanism is described in greater detail
hereinbelow.
[0057] Of course, the illustrated embodiment is just one of many
possible ways to drive and control an automatic 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 imaging device used to guide the biopsy
device, so that the stereotactic device computer would be used to
control the cutter, the angular and longitudinal position of the
piercing needle 20, and the knockout tube position. Additionally,
different driving mechanisms could be employed, such as
substituting a friction drive for the long spur gear drive. In some
instances 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 Ser. No. 08/217,246, or to employ one of the
other needle assembly or needle assembly driving arrangement
embodiments disclosed therein. Of course, any of the embodiments
disclosed in that application may also be used in conjunction with
the inventions herein disclosed.
[0058] In operation, as described in the aforementioned 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 determined 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), commonly 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 guidance system, is given in
U.S. Pat. No. 5,240,011, issued on Aug. 31, 1993, to Michael Assa,
which is here 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 guidance system will enable an operator to advance the
point 58 until it is adjacent the specific lesion region 59 to be
sampled, as illustrated in FIG. 2.
[0059] Once the point 58 is adjacent to the specific lesion region
to be sampled, fine tuning of the location of the point 59 within
the tissue sample is preferably accomplished by actuating the
linear actuator 47 to thereby advance and rest the hollow outer
piercing needle 20 along its axis (the actuator 47 may, however, be
used for rapid piercing as well). While the linear actuator 47
illustrated in FIG. 1, which uses a potential energy device
(spring), is preferred, any of a variety of devices capable of
inducing linear motion may be employed, including solenoids,
pneumatic cylinders, or potential energy devices such as springs,
motors, or the like. In operation of the preferred embodiment, the
cocking lever 54 is pulled proximally against the fixed lever 55 to
compress the spring and cock the carriage assembly 50 in its
proximal position, as shown in FIG. 2. Then, when the needle 20 is
positioned outside the lesion, as illustrated in FIG. 2, the pierce
button 56 is depressed, releasing the carriage housing 50 so that
the :spring uncoils, forcing it rapidly in the direction of the
arrow A (FIG. 3), such that the point 58 of the needle pierces the
lesion 59. Alternatively, this procedure could be automated, using
a needle control unit to send signals to the linear actuator,
which, in tun, would advance and retract the hollow outer piercing
needle 20 along its axis.
[0060] Now with particular reference to FIGS. 8-13, as seen in FIG.
8, the needle 20 is preferably 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 snagging and tearing of
the tissue dig slow linear movement of the needle 20. After 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 actuated to apply a 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 piercing needle 20 in the
vicinity of the tissue receiving port 28, and through the vacuum
lumen 35. This facilitates the prolapse of tissue immediately
adjacent to the tissue receiving port 28 into the interior of the
hollow outer piercing needle 20.
[0061] 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
cannular inner cutter 22 (FIG. 11). The advancement of the inner
cutter 22 is achieved by advancing the slide knob 44 attached 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 tissue sample is packed into the inner cutter as it moves
forward against the needle pin 61 and rests inside the inner cutter
22. The inner cutter 22, containing the tissue sample 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 proximally
toward the tissue cassette housing 24 by friction with the inner
walls of the cannula. Suction created by the vacuum source can also
be used to retain the sample.
[0062] As the inner cutter 22 is withdrawn through the tissue
cassette 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 containment chambers 62 (FIG. 1), as is more fully described
in the related application Ser. No. 08/217,246. Once the tissue
cassette 26 is filled with tissue samples, it may be removed form
the tissue cassette housing 24 and transported to a laboratory for
analysis, without the necessity of handling the samples. If
additional samples are desired, a new tissue cassette 26 may be
immediately inserted into the tissue cassette housing 24 and the
collection of samples may continue.
[0063] Referring 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 frame of the tissue cassette housing 24 (excluding the cassette
26) is preferably molded from a single piece of plastic. If clear
plastic is used, an additional advantage is the resultant ability
to view the collected tissue specimens in the cassette, which is
located 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 24 to be convex, while the inner
surface is substantially flat. The preferred one-piece plastic
cassette housing 24 includes a shaft potion 63, which provides a
conduit for holding the cutter 22 and the knockout pin 36, and the
proximal end portion 52, which in tun is adapted to be mounted on a
post 64 within the housing 14 (FIG. 1), forming a part of the
carriage assembly 50. This portion of the cassette housing thus
provides the support for the entire cantilevered needle assembly
18.
[0064] Yet another advantageous feature of the preferred 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. O-rings 65 fluidly seal the interface
between the housing 24 and the thumbwheel 30, in order to preserve
the vacuum between the port 32 and the vacuum lumen 35 while
simultaneously permitting rotation of the thumbwheel relative to
the fixed housing 24. Because of this inventive feature, the vacuum
may be communicated to the needle 20 from the vacuum port 32 in the
housing 24 no matter what the orientation of the needle is, without
the problem sometimes encountered in prior embodiments wherein the
vacuum tube 34 wraps about the housing 24 as it rotates with the
needle 20. The ability to keep the cassette housing 24 stationary
solves this hose problem.
[0065] FIGS. 14-17 illustrate a procedure enabled by the thumbwheel
30, whereby four tissue samples 60 may be acquired from four
different 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, the integrity of
each sample may be preserved and a record of the location from
which each of the four samples is acquired may be created by
storing the samples in individual sample containment chambers 62
(FIG. 1). FIG. 14 is a cross-sectional view along lines 14-14 of
FIG. 10, which illustrates preparations for the taking of a first
sample 60 (FIG. 11) with the needle 20 and associated vacuum lumen
35 angularly oriented so that the tissue 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, after the
tissue sample has been removed. The 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 approximately 90
degrees counterclockwise. A second sample is to be taken from this
angular location.
[0066] Finally, FIG. 17 is yet another similar view, wherein the
needle 20 has been rotated by the thumbwheel 30 approximately 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
and 360 degrees). A sample has already been taken from this
orientation, as well as from the 180 degree orientation, so that
the void 66 now extends entirely about the needle assembly and four
tissue samples have been removed.
[0067] Now with reference to FIGS. 18 and 19, a modified embodiment
of a portion of the needle assembly 18 of FIGS. 1, 4, and 5 is
illustrated, wherein like elements are designated with like
reference numerals, followed by the letter a. This needle assembly
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).
[0068] Attached to the proximal end of the needle point 58a is a
distal tip 66 of a tissue stop or wire assembly 67, which comprises
a wire 68 which is integral with and extends proximally of the tip
66. The attachment of the point 58a to the tip 66 is preferably
made by brazing, though other equivalent known attachment methods
maybe used as 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 has a diameter or cross-sectional width
just slightly less than the internal diameter of the inner cutter
22a, as illustrated in FIG. 19.
[0069] In operation, with the cutter 22a withdrawn proximally from
the region of the tissue receiving port 28a, the wire assembly 67
is stationary in the lumen of the hollow outer piercing needle 20a.
With the needle in position in the tissue to be sampled, 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 proximal 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 transmitted all the way to the tip 66 so that a
full-volume sample is assured.
[0070] 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 from being sucked or pulled out of the bowl 28a
during withdrawal of the a 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 directly from the bowl by the physician or an
assistant.
[0071] In one preferred embodiment, the inner diameter of the
hollow outer piercing needle 20a was 0.014 inches, and the inner
diameter of the inner cutter 22a was 0.063 inches. The diameter of
the wire 68 was 0.014 inches, and the diameter or cross-sectional
width of the corkscrew portion 69 was 0.060 inches. Of course, many
other dimensions may be utilized as well. Additionally, while a
corkscrew configuration is preferred, many other configurations may
be employed, as long as they function to prevent proximal migration
of the tissue sample, especially during withdrawal of the cutter.
For example, a simple kink in the wire may be used, instead.
[0072] Now with particular reference to FIGS. 5 and 6, the distal
portion of the needle assembly 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 embodiment, two preferably round vacuum ports 70
communicate between the tissue receiving port 28 and the vacuum
lumen 35. The distal port 70 is located distally of the tissue
receiving port opening, so that it lies just proximally of the
point 58 and beneath overhang portion 71 of the needle 20. In the
preferred embodiment, it has a diameter of approximately 0.042
inches. The proximal port 70, on the other hand is significantly
smaller, preferably about one-half the diameter of the larger port
(approximately 0.020 inches), and lies directly beneath the tissue
receiving port 28.
[0073] The second feature of note is related to how the needle
point is ground for sharpening. As illustrated in FIG. 5, it is
preferred that the point be ground to form a plurality of facets 72
(preferably three) wherein no two facets axially intersect within
the circumferential 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 thereby assists its
entry into the tissue receiving port 28. On the other hand, 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.
[0074] Referring now to FIG. 20, a modified embodiment of the
needle assembly 18 illustrated in FIG. 6 is shown, wherein like
elements are designated by like reference numerals, followed by the
letter b. The primary difference between this embodiment and that
of FIG. 6 is the employment of a greater number of vacuum ports
70b, preferably eight, between the vacuum lumen 35b and the tissue
receiving port 28b. In this embodiment, preferably each of the
ports 70b is round and has a diameter of approximately 0.042
inches. Also, in this embodiment all of the ports are located
beneath the opening of the tissue receiving port, as illustrated.
None lie beneath the overhang portion 71b.
[0075] The reason for the two different vacuum port configurations
in FIGS. 6 and 20 is that each has advantages over the other when
sampling certain types of tissue. For example, in relatively fatty
tissue, the eight hole embodiment illustrated in FIG. 20 may have a
greater tendency to clog. Clogging sometimes 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 vacuum 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 lumen 35b partially blocks the vacuum to the distal ports,
causing an uneven and diminished overall vacuum pressure and
thereby reducing 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 vacuum lumen from this port, it
does not build into a mass sufficient to cause a blockage. The
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.
[0076] When relatively hard tissue is being sampled, in containing,
the eight-port embodiment shown in FIG. 20 may be preferable. 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, receiving port. Obviously, the higher number of
evenly spaced ports in the FIG. 20 embodiment will provide this
necessary drawing pressure. Furthermore, hard tissue is much less
likely to actually be drawn into the vacuum ports 70b, so clogging
is not a likely issue.
[0077] 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 embodiments is that
in FIG. 21, the vacuum ports 70c are arranged at an angle .alpha.
with respect to the transverse axis 80 of the needle assembly 18c.
Additionally, the side walls 82 of the tissue receiving port 28c
are preferably arranged at substantially the same angle .alpha.. In
the preferred embodiment, the angle .alpha. is approximately 15-75
degrees. This angled orientation 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 minimizes damage to the cutter blade due to interfering contact
with these edges.
[0078] Yet another modified embodiment of the needle assembly
embodiment illustrated in FIG. 6 is shown in FIG. 22. In this
embodiment, like elements are designated by like reference
numerals, followed by the letter d.
[0079] The FIG. 22 embodiment is designed to assist in solving the
clogging problem discussed with respect to the FIGS. 6 and 20
embodiments and sometimes encountered during the process of
collecting a number of tissue samples from a patient during a
single procedure. As previously discussed, the problem is that bits
of tissue, blood, and other biological debris will, over time,
become detached from the tissue samples being collected and become
lodged in the tissue receiving port 28d, vacuum ports 70d, or in
one of the lumens 23d or 35d. Since the vacuum ports 70d are
relatively 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.
Consequently, 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 cut 22d . Then, when the cutter 22d
is in the closed position, as illustrated, a pressurized saline
solution may be permitted to flow through the cutter lumen 23d into
the needle lumen distally of the 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
accumulated 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.
[0080] As illustrated in FIG. 23, a problem sometimes 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 relatively 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,
preferably comprising a polyamide or a similar low-friction
material or coating, surrounds the remainder of the cutter and
translates axially with it. The sleeve thus acts as an anti-tissue
wrapping bearing, thereby helping to prevent tissue binding, and as
a bearing to the cutter.
[0081] FIG. 25 illustrates a known prior art single-use biopsy
device as disclosed in U.S. Pat. No. 4,699,154 and Re. 34,056, both
previously incorporated herein by reference. It should be noted
that this embodiment is merely representative of many different
types of such devices currently or potentially available, any of
which would be suitably used in conjunction with the inventive
embodiments. However, the illustrated embodiment is illustrative
and will serve as a good point of reference.
[0082] In the device 94, a needle assembly 96 comprises a hollow
outer cutting cannula 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
proximal 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.
Each slide 110 and 112, respectively, is actuated 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 fixed transverse wall (not shown) in the
housing 108. The spring 116 acts between a stop on the slide 112
and the rear 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.
[0083] The front slide 110 may be retained in a proximally
withdrawn position by means of a hook provided on a tongue member
126 protruding from the slide, the tongue member engaging the
bottom edge of the aforementioned 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 130 at the rear
wall 120 of the housing.
[0084] 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
cannula 98, is moved proximally (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 follows the movements of
the slides 110, 112, respectively.
[0085] Thus, when the needle assembly 96 has been placed in the
device, the device is energized in that the slides 110, 112 are
moved simultaneously to their latched positions, whereby the
springs 114, 116 are compressed and would act to return the slides
110, 112 to their initial position if released from the latching
hooks 126, 128, and 130.
[0086] When the needle assembly 96 has 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 biased 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 cannula 98, is still
retained in its energized position. Thus, the inner piercing needle
100 protrudes from the outer cannula 98, thereby exposing the notch
102. Immediately after having reached its initial position,
however, the slide 112 impacts and abuts the hook spring (tongue
member) 126, and interrupts the engagement 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 cannula 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. Thereafter the needle assembly 96 is
withdrawn from the tissue and removed from the sampling device,
following which the sample is analyzed.
[0087] While such a device works fairly well for its intended
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 engaging the tissue
sample within the notch 102, particularly since no source of vacuum
is available, as in the embodiments of FIGS. 1-24, to assist in
collection of the tissue. Consequently, several inventive
embodiments including mechanical elements for capturing the issue
are disclosed herein, each of which dramatically improve the
quality and quantity of the tissue samples collected, on a
consistent basis.
[0088] Referring now to FIGS. 26-28, a modified embodiment 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, with both springs energized, the inner needle 100a is retracted
within the outer cannula 98a, and cutter leaflets 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.
[0089] FIG. 27 illustrates the intermediate position immediately
after the release button 132 (FIG. 25) has been activated. At this
juncture, the spring 116 propels the inner needle 100a distally,
forcing the leaflets 134 open. The sharpened distal edges 136 of
the needle 100a begin to cut tissue, which is contained within the
distal end portion of the needle 100a. Then, upon release of the
spring 114, the outer cannula 98a is propelled distally, as shown
in FIG. 28, causing the leaflets 134 to snap closed to sever and
contain the tissue sample 138.
[0090] It should be noted that this embodiment, while useful as a
modification to the FIG. 25 device, may also be employed in the
FIG. 1 device. In this instance, the inner needle 100a comprises a
rotating cutter, which translates back and forth as previously
described.
[0091] 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
embodiment, the inner needle 100b 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 100b shoots
distally and captures tissue in the opening 148 within the jaws
142, 144. Then, when the spring 114 is released, the outer cannula
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.
[0092] Finally, FIGS. 3,1-34 illustrate a third modified embodiment
of the needle; assembly in the FIG. 25 device. In this embodiment,
like elements are designated by like reference numerals, followed
by a c. Like the FIG. 29 embodiment, the inner needle or "grabber"
100c has been modified, this time to include a plurality of hooked
extractors 150 extending from its distal end. The outer cannula 98c
includes a sharpened cutter point 152. In operation, initially the
grabber 100c is acted into the cutter 98c while the device is in
its energized state, the point 152 being used to pierce the body
wall 154 as the device is guided to the desired tissue sample 138c
(FIG. 32). Then, as illustrated in FIG. 33, the grabber 100c is
shot distally by means of the release of spring 116. As it travels
distally, the hooked extractors 150 become extended and latch onto
the tissue sample 138c. Then, once the second spring 114 is
released, the cutter 98c shoots distally, collapsing the hooked
extractors 150 and severing the tissue sample, which is received
into the lumen of the cutter 98c.
[0093] This embodiment, as well, may be adapted for use with the
device illustrated in FIG. 1. Furthermore, while four exactors 150
are shown, in actuality any desired number may be employed, as long
as they may be fully retracted within the cutter 98c.
[0094] While this invention has been described with respect to
various specific examples and embodiments, 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.
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