U.S. patent application number 12/850844 was filed with the patent office on 2010-11-25 for self-contained, self-piercing, side-expelling marking apparatus.
This patent application is currently assigned to BARD PERIPHERAL VASCULAR, INC.. Invention is credited to Richard M. Chesbrough, Steven E. Field, Ryan L. Goosen, Brain R. Mulder.
Application Number | 20100298696 12/850844 |
Document ID | / |
Family ID | 36568195 |
Filed Date | 2010-11-25 |
United States Patent
Application |
20100298696 |
Kind Code |
A1 |
Field; Steven E. ; et
al. |
November 25, 2010 |
SELF-CONTAINED, SELF-PIERCING, SIDE-EXPELLING MARKING APPARATUS
Abstract
A marking apparatus includes a rigid cannula having a peripheral
wall forming a lumen that carries an imaging marker, a proximal end
coupled to a handle, a lateral opening in the peripheral wall that
is open to the lumen, and a closed-off distal portion having a ramp
adjacent the lumen. The closed-off distal portion extends distally
from the ramp to terminate at a tissue piercing pointed tip. The
ramp of the rigid cannula is curved to transition from the
peripheral wall of the rigid cannula to the lateral opening of the
rigid cannula. The ramp of the rigid cannula is adapted to engage
the distal end of the stylet as the stylet is advanced through the
lumen of the rigid cannula to guide the distal end of the stylet to
a position to substantially close off the lateral opening of the
rigid cannula having the tissue piercing tip.
Inventors: |
Field; Steven E.; (Grand
Rapids, MI) ; Goosen; Ryan L.; (Coopersville, MI)
; Mulder; Brain R.; (Rockford, MI) ; Chesbrough;
Richard M.; (Bloomfield Hills, MI) |
Correspondence
Address: |
C. R. Bard, Inc.;Bard Biopsy Systems
1415 W. 3rd St.
Tempe
AZ
85281
US
|
Assignee: |
BARD PERIPHERAL VASCULAR,
INC.
BARD SHANNON LIMITED
|
Family ID: |
36568195 |
Appl. No.: |
12/850844 |
Filed: |
August 5, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11275918 |
Feb 3, 2006 |
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12850844 |
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10710587 |
Jul 22, 2004 |
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11275918 |
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10707044 |
Nov 17, 2003 |
7424320 |
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10710587 |
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Current U.S.
Class: |
600/426 |
Current CPC
Class: |
A61B 2090/3987 20160201;
A61B 5/064 20130101; A61B 90/39 20160201; A61B 2090/3908
20160201 |
Class at
Publication: |
600/426 |
International
Class: |
A61B 5/05 20060101
A61B005/05 |
Claims
1. A marking apparatus for the percutaneous placement of an imaging
marker in a tissue mass, the marking apparatus comprising: a handle
to be grasped by a user; a rigid cannula having: a peripheral wall
forming a lumen that carries the imaging marker, a proximal end
coupled to the handle, a lateral opening in the peripheral wall
that is open to the lumen, and a closed-off distal portion having a
ramp adjacent the lumen, the closed-off distal portion extending
distally from the ramp to terminate at a tissue piercing pointed
tip, the ramp of the rigid cannula being curved to transition from
the peripheral wall of the rigid cannula to the lateral opening of
the rigid cannula; and a stylet having a distal end, with at least
the distal end of the stylet being flexible, the stylet being
slidably received within the lumen of the rigid cannula for
movement in the lumen, the ramp of the rigid cannula being adapted
to engage the distal end of the stylet as the stylet is advanced
through the lumen of the rigid cannula to guide the distal end of
the stylet to a position to substantially close off the lateral
opening of the rigid cannula having the tissue piercing tip.
2. The marking apparatus of claim 1, wherein only the distal end of
the stylet closes off the lateral opening.
3. The marking apparatus of claim 1, wherein the stylet received in
the lumen has a ready position, where the distal end of the stylet
is spaced inwardly from the closed-off distal portion to form a
marker recess that is in communication with the lateral opening and
that is sized to receive the imaging marker, and an expelled
position, where the distal end of the stylet is advanced a
sufficient distance into the marker recess to expel the imaging
marker contained in the lumen of the rigid cannula through the
lateral opening, and the ramp being adapted to engage the distal
end of the stylet and guide the distal end of the stylet into the
lateral opening to substantially close off the lateral opening of
the rigid cannula after the imaging marker is expelled.
4. The marking apparatus of claim 3, and further comprising
multiple imaging markers contained within the marker recess.
5. The marking apparatus of claim 1, wherein the rigid cannula is
13 gage or less.
6. The marking apparatus of claim 1, wherein the handle, the rigid
cannula, and the stylet are operably coupled to form a
self-contained marking apparatus.
7. A marking apparatus for the percutaneous placement of an imaging
marker in a tissue mass, comprising: a handle to be grasped by a
user; a cannula having: a peripheral wall forming a lumen that
carries the imaging marker, a proximal end coupled to the handle, a
lateral opening in the peripheral wall that is open to the lumen,
and a closed-off distal portion having a ramp adjacent the lumen,
the closed-off distal portion extending distally from the ramp to
terminate at a tissue piercing pointed tip; and a stylet having a
distal end with an angled surface, the stylet being disposed in the
lumen and movable in the lumen between a ready position and an
expelled position, such that when the stylet is advanced through
the lumen to the expelled position the ramp deflects the distal end
of the stylet toward the lateral opening such that at the expelled
position the angled surface is flush with the peripheral wall of
the cannula at the lateral opening of the cannula.
8. The marking apparatus of claim 7, wherein the angled surface of
the distal end of the stylet closes off the lateral opening.
9. A marking apparatus for the percutaneous placement of an imaging
marker in a tissue mass, the marking apparatus comprising: a handle
to be grasped by a user; a cannula having: a peripheral wall
forming a lumen that carries the imaging marker, a proximal end
carried by the handle, a closed-off distal portion terminating in a
self-piercing tip, a ramp integrated with the closed-off distal
portion, and a lateral opening in the peripheral wall, wherein the
lateral opening extends in a region between the proximal end and
the closed-off distal portion of the cannula, the lateral opening
having a proximal extent and a distal extent, the distal extent
being closer to the self-piercing tip than the proximal extent; and
a stylet that includes a distal end, the stylet being slidably
received within the lumen for movement between a ready position,
wherein the distal end of the stylet is spaced inwardly from the
self-piercing tip to form a marker recess in communication with the
lateral opening, and an expelled position, wherein the distal end
of the stylet is advanced a sufficient distance into the marker
recess to expel the imaging marker contained in the lumen through
the lateral opening of the cannula; wherein when the distal end of
the stylet is at the expelled position the distal end of the stylet
is deflected by the ramp to close off the lateral opening of the
cannula between the proximal extent and the distal extent of the
lateral opening.
10. The marking apparatus of claim 9, wherein a portion of the
stylet including the distal end is formed of a flexible material
and includes an angled surface, the angled surface being configured
to close the lateral opening in the cannula between the proximal
extent and the distal extent of the lateral opening when the stylet
is in the expelled position.
11. The marking apparatus of claim 9, wherein a portion of the
stylet including the distal end is formed of a flexible material
and includes an angled surface, the angled surface being flush with
the peripheral wall of the cannula at the lateral opening in the
cannula when the stylet is in the expelled position.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 11/275,918 filed Feb. 3, 2006, which is a continuation of U.S.
application Ser. No. 10/710,587 filed Jul. 22, 2004 and a
continuation-in-part of U.S. application Ser. No. 10/707,044 filed
Nov. 17, 2003, now U.S. Pat. No. 7,424,320, issued Sep. 9, 2008,
all of which are incorporated herein by reference in their
entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates generally to an apparatus for the
percutaneous positioning of an imaging marker for identifying the
location of a lesion in a biopsy procedure. More particularly, the
invention relates to a self-contained marking apparatus that expels
the imaging marker through the side of the marking device.
[0004] 2. Description of the Related Art
[0005] Tissue biopsies are commonly performed on many areas and
organs of the body where it is desirable to ascertain whether or
not the biopsied tissue is cancerous. Often, a lesion or other
tissue to be biopsied is identified through use of an imaging
technique such as a computerized axial tomography (CAT) scan,
ultrasonography, magnetic resonance imaging, and mammography.
[0006] One problem commonly encountered, especially in breast
biopsies, is that the lesion is so small that the biopsy reduces
its size to the extent that it is no longer visible by the imaging
method employed. In such circumstances, it is desirable to place an
imaging marker at the site of the biopsy to enable the medical
practitioner subsequently to locate the lesion quickly and
accurately in the event complete removal of the affected tissue is
indicated. This problem is currently met by placing an imaging
marker at the biopsy area by means of a cannula or similar device
housing the marker.
[0007] There are currently two primary types of marking devices.
One of the primary types is referred to as vacuum assisted biopsy
devices (VABs). The VAB devices are many times integrated with a
mammography imaging system. They include a large diameter cannula,
approximately 9 to 12 gage, or probe that is inserted into the
breast tissue. Instruments, such as a biopsy device and a marking
device, are introduced into the breast tissue through the large
diameter cannula to take biopsy samples or mark a biopsy
location.
[0008] The other primary type is self-contained marking devices
comprising a small diameter, approximately 14 to 17 gage, open-end
cannula and a stylet slidably received within the cannula. A marker
is located in the cannula and expelled out the open-end upon the
advancing of the stylet relative to the cannula.
[0009] One disadvantage of the VAB system is the biopsy and marking
tools are integrated with the mammography imaging system. The
capital investment of this type of system is substantial. Also, the
biopsy and marking tools are typically designed to work only with
the large diameter probe, which tends to lock the hospital or
medical professional into the same source for the imaging system
and the biopsy and marking tools. The VAB systems are also intended
for the same components to be reused, which requires sterilization
after each step. The various components are also typically flexible
to help insert them through the probe. The VAB systems also have a
relatively large diameter probe, which, all things being equal, the
larger the diameter, the greater trauma to the surrounding tissue
and the greater the pain or discomfort for the patient.
[0010] The self-contained marking devices address these
disadvantages of the VAB systems. Since the self-contained marking
device is not integrally incorporated with a particular imaging
system, the self-contained marking devices can be used with any
suitable imaging system and are not limited to just mammography.
This permits the hospital or medical professional to mix and match
the available imaging systems and self-contained marking devices to
obtain the desired performance and cost-effectiveness.
[0011] The self-contained marking devices are typically disposable,
which negates the need to sterilize them after each use. They also
have a much smaller diameter, resulting in much less trauma to the
surrounding tissue and pain to the patient.
[0012] A disadvantage of the self-contained systems is that the
cannula has an open tip through which the marker is expelled. The
open tip is generally closed by the marker residing in the cannula.
However, the marker does not completely close off the open tip and
it is possible for tissue to enter the open end of the cannula
during the positioning of the marking device. The presence of
tissue inside the open end of the cannula can interfere or make
more difficult the expelling of the marker from the cannula.
[0013] The possibility for tissue being present in the open end of
the cannula is, to some extent, related to the distance that the
cannula is inserted through the tissue to the marking site. Thus,
the manner in which the marking device is located at the biopsy
site can impact the presence of tissue in the open end of the
cannula. For example, the self-contained systems are sometimes used
in combination with a positioning cannula that is inserted into the
tissue mass with a stylet closing the end of the positioning
cannula. In such a configuration, the stylet is removed once the
positioning cannula is properly located relative to the biopsy
site. Both the biopsy device and the marking device can be inserted
and withdrawn through the positioning cannula. The use of the
positioning cannula reduces the distance that the open end of the
marking device cannula must travel through the tissue.
[0014] Alternatively, the marking device can be inserted without
the positioning cannula. This is most common when it is desirable
to place a marker without taking a biopsy. Under such
circumstances, it is more likely that tissue will be received
within the open end of the cannula. Therefore, it is more likely
that the tissue will interfere with the expelling of the
marker.
[0015] Therefore, it is desirable to have a self-contained marking
device that can be used with or without a positioning cannula and
which does not receive tissue within the open end of the cannula
that might interfere with the expelling of the marker.
SUMMARY OF THE INVENTION
[0016] The invention relates to a marking apparatus for the
percutaneous placement of an imaging marker at a predetermined
location in a tissue mass to facilitate subsequent determination of
the predetermined location. The marking apparatus comprises a
handle, cannula, and plunger. The handle is to be grasped by a user
to aid in the placement of the marker.
[0017] The cannula comprises a peripheral wall forming a lumen,
with a proximal end carried by the handle, and a distal end
terminating in a self-piercing tip. A lateral opening is formed in
the peripheral wall and is open to the lumen.
[0018] A plunger having a distal end is slidably received within
the lumen for movement between a ready position, where the distal
end is spaced inwardly from the self-piercing tip to form a marker
recess in communication with the lateral opening and sized to
receive an imaging marker, and an expelled position, where the
distal end is advanced a sufficient distance into the marker recess
to expel a marker contained therein through the lateral
opening.
[0019] One or more imaging markers can be positioned within the
marker recess.
[0020] The handle, cannula, plunger are operably coupled such that
they form a self-contained marking apparatus that can be easily and
conveniently handled by a user to effect operation of the marking
apparatus from the ready position to an expelled position.
[0021] The cannula is preferably sufficiently rigid and a distal
end of the cannula is pointed to form the self-piercing tip. The
cannula is 13 gage or less.
[0022] A ramp can be provided on at least one of the plunger and
cannula to aid in expelling an imaging marker. The ramp can be
located in the lumen adjacent the lateral opening. The distal end
of the plunger can be flexible to be deflected toward the lateral
opening by the ramp when the plunger is moved to the expelled
position. The ramp can also be located on the distal end of the
plunger.
[0023] The invention, in one form thereof, is directed to a marking
apparatus for the percutaneous placement of an imaging marker in a
tissue mass. The marking apparatus includes a handle to be grasped
by a user, a rigid cannula and a stylet. The rigid cannula has a
peripheral wall forming a lumen that carries the imaging marker, a
proximal end coupled to the handle, a lateral opening in the
peripheral wall that is open to the lumen, and a closed-off distal
portion having a ramp adjacent the lumen. The closed-off distal
portion extends distally from the ramp to terminate at a tissue
piercing pointed tip. The ramp of the rigid cannula is curved to
transition from the peripheral wall of the rigid cannula to the
lateral opening of the rigid cannula. A stylet has a distal end,
with at least the distal end of the stylet being flexible. The
stylet is slidably received within the lumen of the rigid cannula
for movement in the lumen. The ramp of the rigid cannula is adapted
to engage the distal end of the stylet as the stylet is advanced
through the lumen of the rigid cannula to guide the distal end of
the stylet to a position to substantially close off the lateral
opening of the rigid cannula having the tissue piercing tip.
[0024] The invention, in another form thereof, is directed to a
marking apparatus for the percutaneous placement of an imaging
marker in a tissue mass. The marking apparatus includes a handle to
be grasped by a user, a cannula, and a stylet. The cannula has a
peripheral wall forming a lumen that carries the imaging marker, a
proximal end coupled to the handle, a lateral opening in the
peripheral wall that is open to the lumen, and a closed-off distal
portion having a ramp adjacent the lumen. The closed-off distal
portion extends distally from the ramp to terminate at a tissue
piercing pointed tip. The stylet has a distal end with an angled
surface. The stylet is disposed in the lumen and movable in the
lumen between a ready position and an expelled position, such that
when the stylet is advanced through the lumen to the expelled
position the ramp deflects the distal end of the stylet toward the
lateral opening such that at the expelled position the angled
surface is flush with the peripheral wall of the cannula at the
lateral opening of the cannula.
[0025] The invention, in another form thereof, is directed to a
marking apparatus for the percutaneous placement of an imaging
marker in a tissue mass. The marking apparatus includes a handle to
be grasped by a user, a cannula, and a stylet. The cannula has a
peripheral wall forming a lumen that carries the imaging marker, a
proximal end carried by the handle, a closed-off distal portion
terminating in a self-piercing tip, a ramp integrated with the
closed-off distal portion, and a lateral opening in the peripheral
wall. The lateral opening extends in a region between the proximal
end and the closed-off distal portion of the cannula. The lateral
opening has a proximal extent and a distal extent, the distal
extent being closer to the self-piercing tip than the proximal
extent. The stylet includes a distal end. The stylet is slidably
received within the lumen for movement between a ready position,
wherein the distal end of the stylet is spaced inwardly from the
self-piercing tip to form a marker recess in communication with the
lateral opening, and an expelled position, wherein the distal end
of the stylet is advanced a sufficient distance into the marker
recess to expel the imaging marker contained in the lumen through
the lateral opening of the cannula. When the distal end of the
stylet is at the expelled position the distal end of the stylet is
deflected by the ramp to close off the lateral opening of the
cannula between the proximal extent and the distal extent of the
lateral opening.
[0026] The invention also relates to a method for percutaneously
placing a marker at a predetermined location in a tissue mass using
a self-piercing, side-ejecting, self-contained marking apparatus
comprising a cannula defining a lumen and terminating in a
self-piercing tip, with a lateral opening in communication with the
lumen, and a plunger slidably received within the lumen for
expelling a marker in the lumen through the lateral opening. The
method comprises: inserting the cannula into the tissue mass by
puncturing an exterior of the tissue mass with the self-piercing
tip, and expelling the marker through the lateral opening by
sliding the plunger within the lumen.
[0027] The inserting step can comprise locating the lateral opening
near a predetermined location in the tissue mass where it is
desired to be marked. Preferably, the lateral opening is located
beneath the predetermined location.
[0028] The expelling step comprises expelling multiple markers into
the tissue mass.
[0029] At least one of the multiple markers can be expelled at a
different location in the tissue mass than another of the multiple
markers.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] In the drawings:
[0031] FIG. 1 is a plan view of a self-contained, self-piercing,
and side-expelling marking apparatus comprising an actuator, a
cannula with a side opening, and a stylet for laterally expelling a
marker through the side opening in accordance with the
invention.
[0032] FIG. 2 is an enlarged sectional view of the area II of FIG.
1, illustrating the relationship between the cannula, stylet and
marker prior to the expelling of the marker.
[0033] FIG. 3. is an enlarged top view of the cannula tip of FIG.
2.
[0034] FIG. 4. is an enlarged sectional view of a portion of the
actuator.
[0035] FIG. 5 is a sectional view of the marking device inserted
into a tissue mass such that the cannula side opening is adjacent
an area to be marked, with the stylet shown in a ready position and
the marker still retained within the cannula lumen.
[0036] FIG. 6 is an enlarged sectional view of the cannula tip of
FIG. 5.
[0037] FIG. 7 is a sectional view of the marking device inserted
into a tissue mass such that the cannula side opening is adjacent
an area to be marked, with the stylet shown in a expelled position
and the marker expelled through the side opening into the
surrounding tissue mass.
[0038] FIG. 8 is an enlarged sectional view of the cannula tip of
FIG. 7.
[0039] FIG. 9 is a sectional view of an alternative design for the
cannula and stylet according to the invention, with the stylet
having a flexible tip and shown in the ready position.
[0040] FIG. 10 is a sectional view of the cannula and stylet of
FIG. 9 with the stylet shown in the expelled position.
[0041] FIG. 11 is a sectional view of a second alternative design
for the cannula and stylet according to the invention, with the
stylet having a ramped tip and shown in the expelled position.
DETAILED DESCRIPTION
[0042] FIGS. 1-4 illustrate a self-contained, self-penetrating,
side-expelling marking apparatus 10 according to the invention,
which is capable of the percutaneous placement of a imaging marker
at a desired location, such as at a tissue biopsy site or a lesion
site in a breast. The marking apparatus 10 comprises an introducer
12 and an imaging marker 14 (FIG. 2) contained within the
introducer 12. The introducer 12 includes an actuator 16 having a
hollow interior 18. The actuator 16 comprises a grip portion 20
from which extends a tapered nose portion 22. The grip portion 20
defines a rear opening 24 that provides access to the hollow
interior 18. A pair of detents 26 are formed in the grip portion 20
near the rear opening 24. Channels 28 are formed on the interior
surface of the grip portion 20 and extend from the rear opening 24
to the detents 26.
[0043] The nose portion 22 comprises a guide passage 30 extending
from the tip of the nose portion 22 to the hollow interior 18 of
the actuator 16. The guide passage 30 decreases in diameter
inwardly from the tip of the nose portion to form a cannula seat 32
(FIG. 5).
[0044] A plunger 50 comprises a cylindrical body 52 from which
extend a pair of catches 54 at diametrically opposed positions. The
cylindrical body 52 is sized so that it is slidably received within
the rear opening 24 of the actuator 16 where it is so oriented with
respect to the actuator such that the catches 54 are aligned with
the guide channels 28. The plunger is free to reciprocate within
the grip portion 20 of the actuator 16.
[0045] A cannula 60 is mounted to the introducer 12. The cannula 60
defines a hollow interior in the form of a lumen 62 and comprises a
proximal end 64 and a distal end 66. The proximal end 64 (FIG. 5)
is mounted within the cannula seat 32 to secure the cannula 60 to
the introducer 12. The distal end 66 terminates in a closed-off tip
68 to provide the marking apparatus with self-piercing
functionality. The closed-off tip 68 is illustrated as being
pointed, but other suitable shapes are possible.
[0046] The cannula 60 is preferably 13 gage or less in size. The
cannula 60 is also preferably rigid. That is, the cannula does not
substantially flex. The rigidity of the cannula aids in inserting
the cannula into a tissue mass, without the aid of a guide needle
or guide cannula.
[0047] A side opening 70 is formed in the cannula 60 and extends
entirely through the cannula such that the lumen 62 is in
communication with the exterior of the cannula 60 through the side
opening 70. The side opening is preferably located behind the
closed-off tip 68.
[0048] A ramp 72 is provided on the interior of the cannula 60. The
ramp 72 is illustrated as being integrally formed with the
closed-off tip 68. Such a configuration can result in a solid
distal end 66 as illustrated. However, the distal end can be hollow
and the ramp 72 can be formed by separately from the distal end
66.
[0049] The ramp 72 extends diametrically across the lumen 62 and
terminates at the side opening 70. With this configuration, the
ramp 72 aids in directing an imaging marker 14 stored in the lumen
through the side opening 70 and beyond the exterior of the
cannula.
[0050] A stylet 80 comprising a shaft 82 and a base 84 is received
within the hollow interior 18 of the actuator 16 in a manner such
that the shaft 82 extends through the guide passage 30 and into the
cannula interior 62 and the stylet base 84 lies within the hollow
interior 18 and is mounted to the plunger 50. Thus, the
reciprocation of the plunger 50 relative to the grip portion 20
results in a reciprocation of the stylet 80 within the cannula
60.
[0051] The stylet 80 terminates in a distal end 86, which, when the
marking apparatus is in the ready position, is spaced from the
distal end 66 of the cannula 60 to form a marker recess
therebetween. As illustrated, a single marker 14 is stored within
the marker recess. It is within the scope of the invention for
multiple markers to be received within the marker recess.
[0052] As is shown, the foregoing construction provides a marking
apparatus that is preassembled as a self-contained unit and
prepackaged, all under sterile conditions, thereby affording the
practitioner substantially greater convenience and reliability,
while eliminating the need for sterilizing the self-contained unit
after use. Preferably, the self-contained unit is disposed of after
it is used.
[0053] Referring to FIGS. 5-8, in operation, the introducer 12
begins in the ready condition shown in FIGS. 5 and 6. In this
condition, the distal end 86 of the stylet 80 is received within
the cannula and spaced from the closed-off distal end 66 of the
cannula to define a marker recess in which a marker 14 is stored.
The plunger 50 is in a position relative to the grip portion 20 in
which the catches are outside the grip portion; that is, they are
not received within the detents 26. However, the plunger 50 is so
oriented with respect to the grip portion that the catches 54 are
aligned with the guide channels 28.
[0054] With the introducer in the ready condition, the cannula is
positioned within the tissue mass such that the side opening 70 is
at or near the location of a tissue mass where it is desired to
place the marker. In the case of marking a biopsy site, the side
opening is preferably placed adjacent the biopsy site.
[0055] To place the side opening adjacent the site to be marked,
the medical professional grasps the grip portion 20 of the actuator
and presses the closed-off tip 68 against the exterior of the
tissue mass to puncture the tissue mass. The medical professional
continues applying force to the grip portion 20 to drive the
cannula 60 to the desired location within the tissue mass.
[0056] The closed tip 68 helps separate the tissue of the tissue
mass to make it easier to insert the cannula within the tissue mass
to the desired location. A starter incision can be made in the
exterior of the tissue mass to reduce the initial force need to
start the insertion.
[0057] The used of a side opening 70 instead of a tip opening found
in the prior art self-contained devices helps prevent the
accumulation of tissue within the lumen 62 upon the insertion of
the cannula 60 into the tissue mass. The closed tip 68 also helps
in that it separates the tissue to form a path through which the
side opening passes. Since the side opening is parallel to the
path, there is much less tendency for the insertion of the cannula
to force tissue into the side opening as could occur in the
prior-art front opening cannulae.
[0058] Typically, a suitable imaging system will be used by the
medical professional to help guide the cannula to the desired
location within the tissue mass. Examples of contemporary imaging
systems include: stereotactic, x-ray, ultrasound, CAT scan, or MRI.
The invention is not limited to any particular type of imaging
system.
[0059] Once the cannula is positioned at the desired location, the
plunger 50 is moved from a first or ready condition as illustrated
in FIGS. 5 and 6 to a second or expelled condition as illustrated
in FIGS. 7 and 8. As the plunger is moved, the stylet 80 is
advanced into the marker recess to drive the marker 14 up the ramp
72. The continued advancement of the stylet 80 ultimately drives
the marker 14 through the side opening 70 and into the adjacent
tissue.
[0060] Once the stylet is in the expelled position, the cannula can
be withdrawn to leave the marker in the tissue. To withdraw the
cannula, the medical professional pulls on the actuator to withdraw
the cannula from the tissue mass. After use, the marking apparatus
is disposed of, negating the need for sterilization.
[0061] As illustrated, the rigid cannula in combination with the
closed-off tip 68 provides an ideal structure for inserting the
device directly into the tissue without the need for a guide needle
or cannula. This is advantageous in that it reduces the size of the
opening formed in the tissue and thereby reducing the trauma to the
patient. The closed-off tip is used to puncture the exterior of the
tissue mass. While the marking apparatus of the invention can be
used with a guide needle or cannula, there is no need to do so
because of the self-piercing nature of the invention.
[0062] FIGS. 9 and 10 illustrate an alternative design for the
stylet in the ready and expelled conditions, respectively. The
alternative stylet 80' is essentially identical to the stylet 80,
except that the distal end 66' is made from a resilient material
and has an angled surface 90'. The resilient material permits the
distal end 66' to deflect when contacting the ramp 72', such that
the distal end 66' generally follows the shape of the ramp 72'. The
angle of the angled surface 90' is preferably selected such that
the angled surface substantially closes off the side opening 70'
when the stylet is in the expelled condition, which will ensure
that the marker is completely expelled through the side opening
70'. It will also ensure that no portion of the marker 14 will be
pulled back into the side opening 70' due to the vacuum forces
created upon the withdrawal of the cannula. The angled surface 90'
functions like the ramp 72 in that it helps to deflect the marker
14 through the side opening.
[0063] FIG. 11 illustrates another alternative design for the
stylet and cannula. In this alternative design, the distal end 66''
of the stylet 80'' includes a ramp 72''. A resilient end wall 92''
is used instead of the ramp 72 of the cannula. The space between
the ramp 72'' and the resilient end wall 92'' defines the marker
recess in which multiple markers 14'' are stored. The advancement
of the stylet from the ready condition to the expelled condition
drives the markers up the ramp 72''. When contacted by the ramp
72'', the resilient end wall 92'' deflects to permit the ramp 72''
to slide beneath and into the distal end closed tip 68'' of the
cannula.
[0064] In all of the embodiments, multiple markers can be located
within the cannula and expelled at the same or different locations
within the tissue mass.
[0065] While the invention has been specifically described in
connection with certain specific embodiments thereof, it is to be
understood that this is by way of illustration and not of
limitation, and the scope of the appended claims should be
construed as broadly as the prior art will permit.
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