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Claims  |
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What is claimed is:
1. A biopsy needle instrument comprising:
a housing defining a first cavity and a second cavity,
extending from said housing, an axially elongated stylet having a distal
end and a proximal end and defining a side-facing notch adjacent said
distal end and a cannula coaxially disposed about said stylet, said
cannula having a distal end and a proximal end,
said stylet mounted for axial movement relative to said housing and
relative to said cannula between a first, retracted position and a second,
extended position,
said cannula mounted for axial movement relative to said housing and
relative to said stylet between a first, retracted position and a second,
extended position,
stylet retaining means at the proximal end of said stylet and disposed in
said first cavity,
cannula retaining means at the proximal end of said cannula and disposed in
said second cavity,
means for biasing said stylet distally toward said second, extended
position,
means for biasing said cannula distally toward said second, extended
position,
stylet latch means for retaining said stylet in said first, retracted
position,
cannula latch means for retaining said cannula in said first retracted
position,
means for retracting said stylet from said second, extended position to
said first, retracted position for engagement of said stylet latch means
to retain said stylet in retracted position against the means for biasing
the stylet distally,
separate and discrete means for retracting said cannula from said second,
extended position to said first, retracted position for engagement of said
cannula latch means to retain said cannula in retracted position against
the means for biasing the cannula distally, and
means for releasing said stylet latch means to allow said stylet to move
from said first, retracted position to said second, extended position and
thereafter releasing said cannula latch means to allow said cannula to
move from said first, retracted position to said second, extended
position.
2. The biopsy needle instrument of claim 1 further comprising a lock member
adapted for movement between a first locking position and a second release
position, said lock member in said first position disposed to oppose
release of said stylet latch means and said cannula latch means, and said
lock member, in said second, release position, removed from opposition to
release of said stylet latch means and said cannula latch means.
3. The biopsy needle of claim 2 wherein said lock member is adapted for
movement to a third, intermediate position, said lock member in said third
position removed from opposition to release of said stylet latch means and
disposed to oppose release of said cannula latch means.
4. The biopsy needle of claim 2 or 3 wherein said lock member comprises a
slide element disposed for movement along an outer surface of said
housing.
5. The biopsy needle of claim 1 wherein said bias means for said stylet
comprises a compression spring.
6. The biopsy needle of claim 1 wherein said bias means for said cannula
comprises a compression spring.
7. The biopsy needle of claim 1 wherein said stylet retaining means
comprises a collar attached to said stylet and in communication with said
stylet biasing means.
8. The biopsy needle of claim 1 wherein said cannula retaining means
comprises a collar attached to said cannula and in communication with said
cannula biasing means.
9. The biopsy needle of claim 1 wherein said stylet latch means for
retaining said stylet in said first, retracted position, comprises a first
rocker arm and a first pin, said first rocker arm adapted to rotate about
said first pin between a first position and a second position, said first
rocker arm, in said first position, adapted to engage said stylet
retaining means and to retain said stylet in said first retracted
position, and said first rocker arm, in said second position, spaced from
engagement with said stylet retaining means.
10. The biopsy needle of claim 1 wherein said cannula latch means for
retaining said cannula in said first retracted position, comprises a
second rocker arm and a second pin, said second rocker arm adapted to
rotate about said second pin between an first position and a second
position, said second rocker arm, in said first position, adapted to
engage said cannula retaining means to retain said cannula in said first
retracted position, and said second rocker arm, in said second position,
spaced from engagement with said cannula retaining means.
11. The biopsy needle of claim 1 wherein said means for retracting said
stylet comprises a first slide switch slidably mounted upon and extending
through said housing and attached to said stylet retaining means, such
that when said first slide switch is moved rearwardly, said stylet
retracts from said second extended position to said first retracted
position.
12. The biopsy needle of claim 1 wherein said separate and discrete means
for retracting said cannula comprises a second slide switch slidably
mounted upon and extending through said housing and attached to said
cannula retaining means, such that when said second slide switch is moved
rearwardly, said cannula retracts from said second extended position to
said first retracted position.
13. The biopsy needle of claim 1 wherein said means for releasing said
stylet latch means comprises a button extending from said housing and
attached to said stylet latch means, such that when said button is
depressed, said stylet latch means ceases to retain said stylet.
14. A biopsy needle instrument comprising:
a housing defining a first cavity and a second cavity,
extending from said housing, an axially elongated stylet having a distal
end and a proximal end and defining a side-facing notch adjacent said
distal end and a cannula coaxially disposed about said stylet, said
cannula having a distal end and a proximal end,
said stylet mounted for axial movement relative to said housing and
relative to said cannula between a first, retracted position and a second,
extended position,
said cannula mounted for axial movement relative to said housing and
relative to said stylet between a first, retracted position and a second,
extended position,
stylet retaining means at the proximal end of said stylet and disposed in
said first cavity, wherein said stylet retaining means comprises a collar
attached to said stylet and in communication with said stylet biasing
means,
cannula retaining means at the proximal end of said cannula and disposed in
said second cavity, wherein said cannula retaining means comprises a
collar attached to said cannula and in communication with said cannula
biasing means,
means for biasing said stylet distally toward said second, extended
position, wherein said bias means for said stylet comprises a compression
spring,
means for biasing said cannula distally toward said second, extended
position, wherein said bias means for said cannula comprises a compression
spring,
stylet latch means for retaining said stylet in said first, retracted
position, wherein said stylet latch means for retaining said stylet in
said first, retracted position, comprises a first rocker arm and a first
pin, said first rocker arm adapted to rotate about said first pin between
a first position and a second position, said first rocker arm, in said
first position, adapted to engage said stylet retaining means and to
retain said stylet in said first retracted position, and said first rocker
arm, in said second position, spaced from engagement with said stylet
retaining means
cannula latch means for retaining said cannula in said first retracted
position, wherein said cannula latch means for retaining said cannula in
said first retracted position, comprises a second rocker arm and a second
pin, said second rocker arm adapted to rotate about said second pin
between an first position and a second position, said second rocker arm,
in said first position, adapted to engage said cannula retaining means to
retain said cannula in said first retracted position, and said second
rocker arm, in said second position, spaced from engagement with said
cannula retaining means,
means for retracting said stylet from said second, extended position to
said first, retracted position for engagement of said stylet latch means
to retain said stylet in retracted position against the means for biasing
the stylet distally, wherein said means for retracting said stylet
comprises a first slide switch slidably mounted upon and extending through
said housing and attached to said stylet retaining means, such that when
said first slide switch is moved rearwardly, said stylet retracts from
said second extended position to said first retracted position,
separate and discrete means for retracting said cannula from said second,
extended position to said first, retracted position for engagement of said
cannula latch means to retain said cannula in retracted position against
the means for biasing the cannula distally, wherein said separate and
discrete means for retracting said cannula comprises a second slide switch
slidably mounted upon and extending through said housing and attached to
said cannula retaining means, such that when said second slide switch is
moved rearwardly, said cannula retracts from said second extended position
to said first retracted position
means for releasing said stylet latch means to allow said stylet to move
from said first, retracted position to said second, extended position and
thereafter releasing said cannula latch means to allow said cannula to
move from said first, retracted position to said second, extended
position, wherein said means for releasing said stylet latch means
comprises a button extending from said housing and attached to said stylet
latch means, such that when said button is depressed, said stylet latch
means ceases to retain said stylet, and
a lock member adapted for movement between a first locking position and a
second release position, said lock member in said first position disposed
to oppose release of said stylet latch means and said cannula latch means,
and said lock member, in said second, release position, removed from
opposition to release of said stylet latch means and said cannula latch
means, wherein said lock member comprises a slide element disposed for
movement along an outer surface of said housing.
15. A method of taking a tissue sample comprising the steps of:
providing a biopsy needle instrument comprising a housing defining a first
cavity and a second cavity, extending from said housing, an axially
elongated stylet having a distal end and a proximal end and defining a
side-facing notch adjacent said distal end and a cannula coaxially
disposed about said stylet, said cannula having a distal end and a
proximal end, said stylet mounted for axial movement relative to said
housing and relative to said cannula between a first, retracted position
and a second, extended position, said cannula mounted for axial movement
relative to said housing and relative to said stylet between a first,
retracted position and a second, extended position, stylet retaining means
at the proximal end of said stylet and disposed in said first cavity,
cannula retaining means at the proximal end of said cannula and disposed
in said second cavity, means for biasing said stylet distally toward said
second, extended position, means for biasing said cannula distally toward
said second, extended position, stylet latch means for retaining said
stylet in said first, retracted position, cannula latch means for
retaining said cannula in said first retracted position, means for
retracting said stylet from said second, extended position to said first,
retracted position for engagement of said stylet latch means to retain
said stylet in retracted position against the means for biasing the stylet
distally, separate and discrete means for retracting said cannula from
said second, extended position to said first, retracted position for
engagement of said cannula latch means to retain said cannula in retracted
position against the means for biasing the cannula distally, and means for
releasing said stylet latch means to allow said stylet to move from said
first, retracted position to said second, extended position and thereafter
releasing said cannula latch means to allow said cannula to move from said
first, retracted position to said second, extended position,
placing said locking member in a second release position,
retracting said stylet from a second, extended position to a first,
retracted position,
retracting said cannula from a second, extended position to a first,
retracted position,
placing said locking member in a first locking position,
positioning said stylet so as to allow said stylet to project into the
tissue to be sampled,
placing said locking member in said second release position,
releasing said stylet to allow said stylet to move from said first,
retracted position to said second, extended position and thereafter
releasing said cannula to move from said first, retracted position to said
second, extended position, thereby severing a sample of tissue; and
withdrawing said stylet and cannula together from the tissue. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
The invention relates to the field of surgical biopsy instruments.
A biopsy instrument is frequently used to obtain a piece of tissue for
microscopic examination to determine malignancy, while subjecting the
patient to the least trauma. Typically, the instrument consists of a long,
thin probe, termed a stylet, within a close-fitting hollow needle, termed
a cannula. The stylet and cannula are contained within a firing device
that first projects the stylet into the tumor, followed immediately by the
cannula. The stylet has a notch into which tissue will prolapse when the
stylet enters the tumor. As the cannula slides over the stylet, a small
piece of tissue is then severed from the tumor mass and captured within
the notch of the stylet. The instrument is then withdrawn and the piece of
tissue removed from the stylet.
Lindgren, U.S. Pat. No. 4,699,154, describes a biopsy needle instrument
which projects the stylet and the cannula sequentially when the firing
button is pushed. That instrument requires that the physician load both
the stylet and the cannula at the same time by compressing the stylet and
cannula springs simultaneously.
SUMMARY OF THE INVENTION
In one embodiment of the invention, the biopsy needle instrument comprises
a selectable locking means, movable between two positions including a
first safety position to prevent projection of the stylet and cannula, and
a second position to permit projection of the stylet and the immediate
sequential projection of the cannula.
In another embodiment, the biopsy needle comprises a selectable locking
means movable also to a third or intermediate position which allows the
stylet to be projected separately from the cannula. This arrangement
permits a user to determine if the stylet is in the correct location prior
to projecting the cannula. In this way, if the stylet misses the tumor,
the cannula is not projected, thereby avoiding unnecessary damage to
healthy tissue.
Another aspect of both embodiments is the ability to load the cannula and
stylet separately, and yet fire them sequentially using a single button.
In this way, the physician is not required to work simultaneously against
two stiff springs in loading the instrument for use.
BRIEF DESCRIPTION OF THE DRAWING
This invention is pointed out with particularity in the appended claims.
The above and further advantages of this invention may be better
understood by referring to the following description taken in conjunction
with the accompanying drawings in which:
FIG. 1 is a perspective view of an embodiment of the biopsy needle
instrument of the invention;
FIG. 1a is a side view of the biopsy needle instrument of FIG. 1 in which
the stylet and cannula are projected automatically in succession, while
FIG. 1b is a top view of the instrument of FIG. 1, and FIG. 1c is an
enlarged view of the forward end of the cannula and stylet of FIG. 1;
FIG. 2 is a cross-sectional view taken at A--A of FIG. 1a;
FIG. 3a is a cross-sectional view of the instrument of FIG. 2 with the
selector switch set to a first safety position, FIG. 3b is the
cross-sectional view of the firing mechanism of the instrument of FIG. 3a
with the selector switch set to project both the stylet and the cannula,
FIG. 3c is a similar view with the stylet firing; and FIG. 3d is a similar
view with the cannula firing;
FIGS. 4(a) through 4(d) are cross-sectional side views of the firing
mechanism of another embodiment of the invention which permits the
separate projection of stylet and cannula, in FIG. 4a the selector switch
is in a first safety position; in FIG. 4b the selector switch is in
position to fire the stylet separately from the cannula and the stylet is
firing; in FIG. 4c the stylet fully projected, and in FIG. 4d the selector
switch is in position to fire the cannula and the cannula is firing.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Structure
Referring to FIG. 1, a biopsy needle instrument 5 of the invention has a
housing 8, consisting of an upper housing 10 and a lower housing 16.
Stylet 18 and cannula 20 project from housing 8. Forward loading slide
switch 12 and rearward loading slide switch 14 protrude from the upper
housing and are constrained to move within slots 26, 28. A firing button
22 and a selector switch 24 also project from the housing 8.
Referring to FIGS. 1(a) and (b), when the stylet 18 is to be loaded for
firing, the rear loading slide switch 14, attached to the stylet 18, is
slid rearwardly (arrow R.sub.R) within a slot 26. When the stylet 18 is
fired, the rear loading slide switch 14 moves forwardly within the slot.
Similarly, when the cannula 20 is to be loaded for firing, the forward
loading slide switch 12, attached to the cannula 20, is slid rearwardly
(arrow F.sub.R) within slot 28. When the cannula 20 is fired, the forward
loading slide switch 12 moves forwardly within the slot.
FIG. 2 shows the instrument firing mechanism positioned within the lower
housing 16. Stylet 18 is located coaxially within cannula 20, and the
forward end of each projects through the forward end of the lower housing
16. The rearward end of cannula 20 attaches to the cannula retaining
collar 38 which is biased forward (arrow F) by spring 40. The cannula
retaining collar 38 and spring 40 are located within a forward cavity 9 of
the lower housing 16. The rearward end of the spring 40 rests against the
rear lever 56 of the forward rocker arm 46 and is held in the compressed
state by engagement of the cannula retaining collar 38 by the latch
portion 60 of the forward rocker arm 46. The forward rocker arm 46 is
prevented from pivoting about the pin 58 (thereby releasing cannula
retaining collar 38 and spring 40) when the selector switch 24 is in the
position designated as "0" by a forward restraining projection 32 of
forward arm 62 of the selector switch 24.
The rearward end of the stylet 18 extends through cannula 20, cannula
retaining collar 38, and spring 40 and is attached to a stylet retaining
collar 36 which is biased forward (arrow F) by spring 44. The stylet
retaining collar 36 and spring 44 are located within a rearward cavity 11
of the lower housing 16. The rearward end of spring 44 rests against the
rear lever 54 of the rearward rocker arm 48 and is held in the compressed
state by engagement of the stylet retaining collar 36 by the latch portion
52 of the rearward rocker arm 48. The rearward rocker arm 48 is prevented
from pivoting about the pin 50 (and thereby releasing stylet retaining
collar 36 and spring 44) when the selector switch 24 is in the position
designated as "0" by a rearward restraining projection 34 of the rearward
arm 64 of the selector switch 24.
As the selector switch 24 is moved forward to the position designated "2",
the forward restraining projection 32 is moved forward away from the
forward rocker arm 46. Rear restraining projection 34 is simultaneously
move forward away from the rearward rocker arm 48. The rearward rocker arm
48 is thus free to pivot counterclockwise (arrow P) about pin 50. The
forward rocker arm 46 is also free to pivot counterclockwise.
Operation
Referring also to FIG. 3a et seq. and FIG. 1b, with the selector switch 24
placed in position "2" (FIG. 3d), the cannula 20 is loaded by moving the
front loading slide switch 12 rearwardly (arrow F.sub.R). The front
loading slide switch 12 is attached to the cannula retaining collar 38,
and as the front loading slide switch is moved rearwardly, the cannula
retaining collar 38 is also moved rearwardly and spring 40 is compressed.
The compression puts pressure against rear lever 56 of the forward rocker
arm 46 causing it to rotate clockwise (arrow C.sub.F) about pin 58. This
also causes the forward rocker arm 46 to rotate clockwise until the latch
portion 60 of the forward rocker arm 46 engages the cannula retaining
collar 38. At this point the cannula 20 is loaded for firing.
The stylet 18 is then loaded by moving the rear loading slide switch 14
rearwardly (arrow R.sub.R). The rear loading slide switch 14 is attached
to the stylet retaining collar 36, and as the rear loading slide switch 14
is moved rearwardly, spring 44 is compressed. The compression puts
pressure against rear lever 54 of the rearward rocker arm 48 causing it to
rotate clockwise (arrow C.sub.R) about pin 50. This also causes the
rearward rocker arm 48 to rotate clockwise until the latch portion 52 of
the rearward rocker arm 48 engages the stylet retaining collar 36. At this
point the stylet 18 is also loaded for firing. The selector switch is then
moved to position "0" (FIG. 3a) so the restraining projections 32 and 34
of the selector switch 24 prevent the cannula 20 and stylet 18
respectively from being accidentally fired.
A benefit of the separately loadable cannula and stylet is that to load the
device, only one spring need be compressed at a time, thereby
significantly reducing the amount of effort required.
Referring to FIG. 3b, to fire the stylet 18 and the cannula 20 in quick
succession, the selector switch 24 is moved forward to position "2",
moving the restraining projections 32, 34 forward away from the rocker
arms 46, 48 respectively. In this position both the forward 46 and
rearward 48 rocker arms can rotate freely about the pins 58 and 50
respectively.
Referring to FIG. 3c, when the firing button 22 is pressed rearwardly
(arrow R), the rocker arm 48 rotates counter-clockwise (arrow P.sub.R)
about pin 50 causing latch portion 52 of the rocker arm 48 to be pulled
away from the stylet retaining collar 36. This allows spring 44 to expand
and project the stylet retaining collar 36 and stylet 18 forward (arrow
E.sub.R).
Referring to FIG. 3d, as spring 44 expands, it propels the stylet retaining
collar 36 against the rear lever 56 of the forward rocker arm 46. The
momentum cf the stylet retaining collar 36 forces the rear lever 56
forward (as shown by arrow 1) and causes forward rocker arm 46 to rotate
counter clockwise (arrow P.sub.F) about pin 58. As the rocker arm 46
rotates, it pulls the latch portion 60 of rocker arm 46 away from the
cannula retaining collar 38. This releases the spring 40 and projects
collar 38 and cannula 20 forward (arrow E.sub.F).
Having shown an illustrative embodiment, those skilled in the art will
realize many variations are possible which will still be within the scope
and spirit of the claimed invention. Therefore, it is the intention to
limit the invention only as indicated by the scope of the claims.
Other embodiments are within the following claims. For example, referring
to FIG. 4a et seq. selector switch 24' has an additional intermediate
position termed "1". In this embodiment, the forward arm 62' of the
selector switch 24' is shorter than the forward arm 62 in the previously
described embodiment so that when selector switch 24' is moved forward to
the position "1" (FIGS. 4b and 4c), the rear restraining projection 34 is
moved far enough forward so as to permit the rear rocker arm 48 to pivot
about pin 50, while the forward restraining projection 32' still prevents
the forward rocker arm 46 from pivoting about pin 58. As the selector
switch 24 is moved further forward to the position designated as "2" (FIG.
4d), the forward restraining projection 32' moves further forward and away
from the forward rocker arm 46 and permits the forward rocker arm 46 to
pivot about pin 58.
To project the stylet 18 and the cannula 20 separately, the selector switch
24' is slid into the intermediate position, termed "1". This moves the
rear restraining projection 34 forward of the rearward rocker arm 48
permitting the rearward rocker arm 48 to rotate counterclockwise (arrow
P.sub.R) about pin 50. However, due to the unequal length of the arms, the
forward restraining projection 32' remains in a position to prevent rocker
arm 46 from rotating counterclockwise (arrow P.sub.F) about pin 58.
Referring to FIG. 4b, the stylet 18 is fired by pressing the firing button
22 rearwardly, (arrow R). Again this causes the rearward rocker arm 48 to
rotate counterclockwise (arrow P.sub.R) and move the latch portion 52 of
the rearward rocker arm 48 away from the stylet retaining collar 36. This
releases spring 44 which projects (arrow E.sub.R) the stylet 18 and stylet
retaining collar 36 forward.
Referring to FIG. 4c, when the stylet retaining collar 36 hits the rear
lever 56 of the forward rocker arm 46, the rear lever 56 is prevented from
moving by the forward restraining projection 32'. This then prevents the
forward rocker arm 46 from rotating counterclockwise. At this point the
stylet 18 is fully extended but the cannula 20 has not been fired.
To fire the cannula 20, the selector switch 24' is then moved into the
position "2", moving the forward restraining projection 32' forward and
away from the forward rocker arm 46. Although the cannula 20 may now be
fired, it will not fire spontaneously because the compressive force of
spring 40 exceeds the expansion force of spring 44 on the rearward lever
56 of the forward rocker arm 46. This force-couple attempts to cause the
rocker arm 46 to rotate clockwise and to cause the rearward lever 56 of
the forward rocker arm 46 also to rotate clockwise. Therefore the latch
portion 60 of the forward rocker arm is held against &he cannula retaining
collar 38, holding the spring 40 in compression.
Referring to FIG. 4d, to fire the cannula 20, a forward force (arrow A) is
applied to the rear loading slide switch 14. This forces the stylet
retaining collar 36 further against the forward lever 56 and exceeds the
compressive force of spring 40. This permits the forward rocker arm 46 to
rotate counterclockwise (arrow P.sub.F) away from the cannula retaining
collar 38, releasing spring 40 and projecting the cannula retaining collar
38 and the cannula 20 forward.
To remove the biopsy sample once the cannula 20 has been fired, the cannula
20 and stylet 18 are withdrawn from the tumor and the cannula 20 is then
retracted by | | |
