 |
Description  |
|
|
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to apparatus designed to guide a
catheter or needle to a preselected point within a patient's body, and
more particularly, to a guidance device for inserting biopsy needles,
drainage catheters and the like, into a patient's body in conjunction with
a C.T. scanner.
2. Description of the Prior Art
In recent years, total body C.T. scanners have become commonly used to
provide doctors with a cross-sectional picture of a patient's internal
organs and tissues. This imaging modality can define abnormal tissues but,
in many situations, cannot determine what has caused the abnormality.
Through the use of C.T. scanner technology, physicians are able to
accurately place biopsy needles and drainage catheters into abnormal
tissues with a high degree of success and with a low morbidity and
mortality to the patient. This approach has changed the way in which
medical diagnoses are made. For example, exploratory laparotomies for
suspected tumors have decreased significantly in recent years in view of
the increasing use of C.T. guided biopsies of suspicious masses in the
abdomen.
While C.T. scanners that are presently available are capable of measuring a
proposed trajectory for a biopsy needle or drainage catheter to within 0.1
millimeters with respect to depth, and within 0.1 degree with respect to
angular orientation, there are no known devices available which can
accurately and easily utilize such information to properly position a
biopsy needle or drainage catheter relative to the patient's body. To the
applicant's knowledge, most physicians perform C.T. guided procedures by
initially positioning the needle or catheter at a rough estimation of the
desired angle, and by then slowly advancing the needle or catheter into
the patient's body, taking numerous C.T. scans along the way to determine
the actual position of the needle or catheter, and altering its trajectory
as needed. This trial and error technique has major disadvantages. First,
it usually requires a relatively long period of time and causes the
patient to remain in a fixed position which most patients find
uncomfortable. Secondly, additional radiation may be harmful to the
patient. Additionally, in institutions where C.T. access is limited, a
lengthy procedure may excessively utilize the available time, preventing
other patients from being studied.
C.T. scanner guided stereotactic brain surgery is known in the art, and
various patents disclose frames for attachment to a patient's head for
performing a stereotactic surgical procedure. Such stereotactic surgical
apparatus for use in conjunction with C.T. scanners is disclosed in U.S.
Pat. Nos. 4,341,220 and 4,592,352. The brain, because of its consistent
relationship to the boney skull, can have a rigid frame attached to it
which can then provide the needed reference coordinates from which various
paths can be calculated. However, with respect to other parts of the body,
underlying organs and tissues do not bear a constant relationship to the
surface anatomy. In addition, parts of the body other than the head lack a
sufficiently rigid structure to which a stereotactic frame can be reliably
attached.
U.S. Pat. No. 4,058,114 to Soldner discloses a guide aide designed to
introduce a puncturing cannula into the body under the guidance of
ultrasound imaging equipment. The disclosed apparatus requires that the
guide aide be secured to the ultrasound transducer. The disclosed
apparatus further requires a targeting aide fastened to the ultrasound
image viewing screen. The ultrasound transducer rests upon the patient's
body and provides a support for the guide aide. In contrast, C.T. scanners
do not utilize a transducer in contact with the pateint's body, and
accordingly, the guide aide and targeting aide disclosed by Soldner could
not be used in conjunction with C.T. guided interventional procedures.
U.S. Pat. No. 4,583,538 issued to Onik et al. discloses an apparatus
designed to facilitate C.T. guided biopsies of the body. The stereotaxis
guide instrument disclosed in this patent is floor-mounted and is designed
to position a needle guide by moving the same through any of three
perpendicular axes. Angular rotations about such axes are permitted to
orient the needle guide in any desired direction.
However, the articulated arm configuration disclosed by Onik et al.
requires the user to manipulate a great number of cranks, bearings, and
arms before a needle can be inserted into the patient.
Accordingly, it is an object of the present invention to provide a guidance
device which allows a physician or other user to perform a C.T. guided
interventional procedure within a patient's body accurately, easily and
more expeditiously than methods or apparatus used in the past to perform
such procedures.
It is another object of the present invention to provide such a guidance
device which eliminates the need to make repeated C.T. scans in order to
insure that the biopsy needle or drainage catheter is correctly aimed
toward the target area.
It is still another object of the present invention to provide such a
guidance device which quickly and easily converts the angle and depth
information provided by the C.T. scanner computer to settings which direct
the biopsy needle or drainage catheter to the desired target area.
It is a further object of the present invention to provide a guidance
device which is easy to operate and manipulate.
It is a still further object of the present invention to provide such a
guidance device which avoids interference with the operation of a biopsy
needle or drainage catheter after the same has been inserted into the
patient's body.
Yet another object of the present invention is to provide such a guidance
device which is of simple and inexpensive construction.
These and other objects of the present invention will become more apparent
to those skilled in the art as the description thereof proceeds.
SUMMARY OF THE INVENTION
Briefly described, the present invention is a guidance device allowing a
user to accurately place a biopsy needle, drainage catheter, or the like
within the body of a patient, and including a base which may be supported
in the user's hand, the base preferably being generally planar and
extending along a longitudinal axis. A bubble level or similar leveling
indicator is secured to the base for indicating whether the longitudinal
axis of the base is lying in a horizontal plane. A circular type bubble
level provides the advantage of ensuring that both the longitudinal axis
of the base and the pivot axis lie in a horizontal plane. A needle support
arm is pivotally coupled to the base adjacent an end thereof for movement
about a generally horizontal pivot axis. A protractor is provided adjacent
the pivotal coupling between the needle support arm and the base for
indicating the relative angular relationship therebetween. Needle guides
are secured to the needle support arm for slidingly supporting the biopsy
needle or drainage catheter at a desired angle, as indicated by the
protractor, thereby permitting the user to guide the needle or catheter
into the patient's body at the predetermined angle.
In the preferred embodiment of the present invention, a reference line is
formed upon the upper surface of the base, the reference line lying within
the vertical plane in which the biopsy needle or drainage catheter is
supported by the guidance device. The C.T. scanner projects a transverse
reference beam of light across the patient's body to indicate the location
of the vertical plane through which the scan is being sectioned. In
operation, the user positions the base of the guidance device to align the
reference line formed thereupon with the aforementioned transverse
reference beam of light projected by the C.T. scanner in order to maintain
the catheter within the vertical plane of the patient's body being
scanned.
The needle support arm has graduated markings formed along its length and
allows the user to accurately measure the depth to which the tip of the
biopsy needle or drainage catheter has been inserted into the patient's
body.
Preferably, the pivotal coupling between the needle support arm and the
planar base can be selectively locked at a desired angle in order to
maintain the biopsy needle or drainage catheter at such angle during
insertion.
Once the biopsy needle or drainage catheter has been placed into the
patient's body, the guidance device should be easily removable from the
biopsy needle or drainage catheter in order to avoid interference
therewith. Accordingly, another aspect of the present invention is the
ability of the needle support arm to releasably support the biopsy needle
or drainage catheter at the desired angle. In this regard, one embodiment
of the present invention utilizes needle guides which are easily
disengaged from the biopsy needle or drainage catheter after the same is
placed in the body. In an alternate embodiment of the present invention,
the needle guides are releasably secured to the needle support arm and are
disengaged therefrom after the biopsy needle or drainage catheter is
placed in the body.
The guidance device of the present invention preferably includes a handle
allowing the user to more easily support the planar base of the guidance
device adjacent the patient's body.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a guidance device embodying the present
invention.
FIG. 2 is an end view of the guidance device shown in FIG. 1.
FIG. 3 is a side view of the guidance device shown in FIG. 1 wherein a
handle has been omitted.
FIG. 4 is a partial top view of the left most portion of the guidance
device shown in FIG. 3, including a circular bubble level affixed thereto.
FIG. 5 is a perspective view of a patient lying upon a C.T. scanning table
and wherein reference beams of laser light projected by the C.T. scanner
are indicated.
FIG. 6 is a partial view of the needle support arm of the guidance device
illustrating a needle guide releasably secured thereto.
FIG. 7 is a sectional view of the needle support arm shown in FIG. 6 taken
through lines 7--7.
FIG. 8 is a perspective view of a portion of the needle support arm
including a pair of offset needle guides directed in opposing directions.
FIG. 9 is an end view of the needle support arm shown in FIG. 8 viewed from
lines 9--9.
FIG. 10 is an illustration of a C.T. scanner imaging screen displaying a
sectional scan through a patient's abdomen, with superimposed position
coordinates.
FIG. 11 is a second C.T. scanner computer screen image showing the tip of
the biopsy needle after the same has been inserted into the patient toward
the target area.
FIG. 12 is an alternate embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference to FIG. 1, a guidance device is identified generally by
reference numeral 20 including a generally planar base 22 having a first
end 24, an opposing second end 26, and a longitudinal axis extending
therebetween. Planar base 22 includes an upper planar surface 28 and an
opposing lower surface 30 (see FIG. 3). As shown in FIGS. 1 and 2, a
handle 32 may be provided at end 26 of planar base 22, handle 32 being
contoured to the user's grip for allowing the user to support guidance
device 20 in position relative to a patient's body.
As shown in FIGS. 1-4, a circular bubble level 34 is secured to upper
surface 28 of planar base 22 proximate second end 26 thereof. Bubble level
34 includes a bulls-eye 36 for indicating to a user that planar base 22 is
lying in a horizontal plane.
Guidance device 20 also includes a vertical support 38 secured to upper
surface 28 of planar base 22 adjacent first end 24 thereof and extending
perpendicularly to planar base 22. The right-most (relative to FIG. 3) end
40 of vertical support 38 preferably extends beyond first end 24 of planar
base 22 and has a semi-circular contour. Angle markings 42 are formed upon
the inner surface 44 of vertical support 38 along the semi-circular
periphery of right most end 40 in order to provide a protractor. The
radial center of the aforementioned protractor is indicated by reference
numeral 46.
As shown in FIGS. 1-3, a needle support arm 48 extends between a first end
50 and a second end 52 and is substantially planar. First end 50 is
preferably semi-circularly shaped and has the same radius of curvature as
semi-circular end 40 of vertical support 38. Needle support arm 38 is
pivotally coupled to end 40 of vertical support 38, the pivotal coupling
aligning the radial center of semi-circular end 50 with the radial center
46 of semi-circular end 40. In this manner, needle support arm 48 is
maintained perpendicular to planar base 22 and is free to pivot with
respect thereto. As shown in FIG. 2, the pivotal coupling between needle
support arm 48 and vertical support 38 may be made by a screw 54 passing
through aligned holes (not shown) formed in the needle support arm 48 and
vertical support 38. Preferably, screw 54 is engaged by a wing nut 56
which, when tightened, locks needle support arm 48 at a predetermined
angle relative to planar base 22. Screw 54 passes along the horizontal
pivot axis about which needle support arm 48 pivots. This pivot axis lies
generally perpendicular to the longitudinal axis of base 22.
In order to permit a user to view the angular markings 42 forming the
protractor, semi-circular end 50 of needle support arm 48 is preferably
made of a transparent material. A reference line 58 passing through
pivotal coupling point 46 and extending along the longitudinal axis of
needle support arm 48 is provided for allowing the user to read off from
the protractor the present angle of needle support arm 48 relative to
planar base 22.
As noted earlier, the guidance device of the present invention is intended
to slidingly support a biopsy needle, drainage catheter, or the like upon
needle support arm 48. In this regard, a pair of needle guides 58 and 60
are secured to needle support arm 48 for slidingly supporting a biopsy
needle, drainage catheter, or the like. Within FIG. 1, a biopsy needle,
designated by reference numeral 62, is shown supported by needles guides
58 and 60 for sliding movement along the longitudinal axis of biopsy
needle 62. In this manner, a user can slide the shaft of needle 62 along
guides 58 and 60 and guide the needle 62 into the patient's body at a
desired angle.
As noted above, the guidance device should be easily disengaged from the
needle once the needle is properly placed within the patient's body. For
example, a physician or other user of the guidance device would probably
find it difficult to efficiently operate the biopsy needle in order to
obtain a tissue sample if the needle were engaged with the guidance
device.
Accordingly, the guidance device shown in FIGS. 1-3 provides needle guide
58 secured to needle support arm 48 at a first point and including a first
V-shaped engagement surface 64 forming a channel opening outward in a
first direction for slidingly engaging one side of needle 62. Needle guide
60 is secured to needle support arm at a second point spaced apart from
needle guide 58 and proximate first end 50 of needle support arm 48.
Needle guide 60 also includes a V-shaped engagement surface 66 forming a
channel which opens outwardly in a direction opposite to that for
engagement surface 64, as shown in FIG. 8. By continuously maintaining the
walls of needle 62 engaged with surfaces 64 and 66, as shown in FIG. 9,
the user can easily maintain the needle 62 at the desired angle while
sliding the same towards its target.
FIGS. 6 and 7 show an alternate form of needle guide which may be used in
conjunction with needle support arm 48. As shown in FIG. 6, needle guide
68 includes a hole 70 which is of a size that just permits the shaft of
the biopsy needle or drainage catheter 62 to be slidingly passed
therethrough. Needle guide 68 includes an enlarged tab 72 connected by a
reduced width portion 71. Tab 72 is adapted to be inserted within a
slightly oversized hole 74 formed in needle support arm 48. A reduced
width channel 75 extends from oversized hole 74 and is adapted to
slidingly receive portion 71 of needle guide 68 to releasably lock needle
guide 68 to needle support arm 48. Preferably, a pair of such needle
guides 68 are releasably secured to needle support arm 48 at spaced apart
points lying along the longitudinal axis of the needle support arm 48. The
biopsy needle or drainage catheter is caused to pass simultaneously
through both of such needle guides to maintain the needle or catheter in
proper alignment with needle support arm 48. Once the needle has been
placed within the patient, needle guides 68 are slid out of channels 75
and are then released from their cooperating holes 74 in support arm 48,
and the remainder of the guidance device is removed, leaving only needle
guides 68 in engagement with the shaft of needle 62.
As mentioned earlier, one of the objects of the present invention is to
allow a physician or other user to determine the depth of which the tip 76
of biopsy needle 62 has been inserted into the patient's body. For this
purpose, periodic graduations, such as centimeter markings, designated
generally by reference numeral 78 are printed or otherwise marked upon
needle support arm 48. By noting a fixed point upon the needle or
catheter, and its relation to the graduations 78, the user can accurately
guage the depth to which the tip of the needle or catheter has been
inserted.
Referring now to FIG. 5, a patient 80 is shown lying upon a movable,
computer-controlled scan table 82 of a C.T. scanning system. Other
components of the C.T. scanning system are omitted for clarity. The C.T.
scanner is designed to provide a cross-sectional image of the patient's
body taken through a vertical scan plane. Two such vertical scan planes
are shown in FIG. 5 by dashed lines 84 and 86.
As a reference aide, C.T. scanners are designed to project reference beams
of laser light toward the scanning table to indicate the portion of the
patient's body being scanned. A first reference beam, indicated by dashed
line 88, is projected longitudinally along the center of scanning table 82
to indicate the center point of the scanned image. A first transverse beam
of laser light, designated by dashed line 90, is projected by the C.T.
scanner indicating the location of the vertical plane through which the
patient's body is being scanned. A second transverse beam of laser light,
indicated by dashed line 92, is projected by the C.T. scanner a known
distance apart from the first transverse beam 90. This second transverse
beam of laser light is provided principally to aid a technician or
physician in properly positioning the patient's body for scanning before
the scanning table is actually advanced into the scanner. It is often
difficult for a physician to insert a biopsy needle within the patient's
body without moving the scanning table out of the scanning apparatus.
Accordingly, the scanning table 82 may be withdrawn from the scanning
apparatus by the known distance separating transverse beams 90 and 92 in
order to cause transverse beam 92 to overlie the area of the patient's
body that was scanned just immediately prior to the movement of scanning
table 82.
To help insure that the biopsy needle, drainage catheter or like device
will hit its intended target, it is desirable for the user to maintain the
needle or catheter within the vertical plane viewed by the C.T. scanner.
In this regard, a reference line 94 is formed upon upper surface 28 of
planar base 22 extending substantially between first end 24 and second end
26 thereof. Reference line 94 is positioned to lie within the vertical
plane that contains the biopsy needle 62 supported by needle support arm
48. In other words, reference line 94 coincides with the vertical
projection of biopsy needle 62 onto planar base 22. During use, the user
positions planar base 22 so as to maintain reference line 94 in alignment
with the appropriate transverse laser light beam 90 or 92 (see FIG. 5),
while simultaneously maintaining planar base 22 horizontal, thereby
insuring that needle 62 lies within the vertical plane of the patient's
body being sectioned by the C.T. scanner.
In order to use guidance device 20, a patient is scanned in conventional
fashion to determine the location of the abnormal area. An image, like
that shown in FIG. 10, is displayed upon the C.T. scanner computer screen
showing a cross-section of the patient's body. The outline of the
displayed image is designated within FIG. 10 by reference numeral 96. The
computer screen can selectively superimpose an x-axis 98 and a y-axis 100
over the displayed image of the patient's body. Referring briefly to FIG.
5, y-axis 100 corresponds to the position of longitudinal reference beam
88. For purposes of explanation, it will be presumed that the marker
designated by reference numeral 102 within FIG. 10 designates the tissue
mass that is to be biopsied.
While viewing the computer generated image shown in FIG. 10, the physician
determines the best straight line path lying within the sectioned plane of
the patient's body to reach target 102 without injuring surrounding organs
or blood vessels. Again, for the sake of explanation, it will be presumed
that the angled path indicated by dashed line 104 represents the best path
for inserting a biopsy needle to reach target area 102. By using a cursor
on the computer screen, the radiologist can mark both the target area 102
and the site 106 at which the needle will be inserted. The C.T. scanner
computer can then easily compute the distance from insertion site 106 to
reference axis 100. The C.T. scanner computer can also be used to display
the angle that proposed path 104 forms with either x-axis 98 or y-axis
100. In addition, the C.T. scanner computer is also capable of measuring
and displaying the length of the path from insertion site 106 to target
area 102.
Once the physician has obtained the information set forth above, the
radiologist locates the proposed insertion site upon the patient's body by
starting at the intersection of longitudinal light beam 88 and the
appropriate transverse beam 90 or 92, and measuring off the distance
indicated by the computer between longitudinal beam 88 and entry site 106.
A radiopaque marker is placed on this point of the patient's body, and a
second scan is performed to confirm that the insertion site has been
properly marked. The biopsy needle 62 is then inserted into the guidance
device, as shown in FIG. 1, and the needle support arm angle relative to
planar base 22 is locked at the angle indicated by the C.T. scanner
computer. The user then supports guidance device 20 in close proximity to
the patient's body, with the tip 76 of biopsy needle 62 directed toward
insertion site 106. The user then views the circular bubble level 34 and
adjusts the position of guidance device 20 until planar base 22 is
essentially horizontal. Simultaneously, the user adjusts guidance device
20 until reference line 94 coincides with transverse reference beam 90 or
92, as appropriate. Tip 76 of biopsy needle 62 is contacted against
insertion site 106, and the user then notes the initial position of biopsy
needle 62 relative to the graduated markings 78. The user then advances
biopsy needle into the patient's body until the needle has been advanced
to the depth indicated by the C.T. scanner computer. Depending upon the
size of the lesion or target mass, and its distance from the skin, perhaps
one intermediate scan may be desired to insure that needle 62 has not been
deflected and is within the selected plane and along the proper
trajectory. FIG. 11 illustrates such an intermediate scan with biopsy
needle 62 advanced midway toward target area 102.
In FIG. 12 an alternate embodiment of the invention is shown wherein
components corresponding to those previously described in regard to FIGS.
1-4 are labeled with corresponding reference numerals. The principal
difference between the guidance device 108 shown in FIG. 12 and guidance
device 20 shown in FIGS. 1-3 is the manner in which needle support arm 48
is secured to planar base 22. As shown in FIG. 12, the lower end 50' is
pivotally coupled to end 24' of planar base 22 by a hinged coupling 110,
including hinge pin 46 and releasable locking wing nut 56. A protractor
112 extends perpendicularly from planar base 22 proximate end 24' thereof
and adjacent side edge 114 of needle support arm 48 in order to indicate
the relative angular relationship between needle support arm 48 and planar
base 22. Needle guides 58 and 60 are secured to needle support arm 48 for
releasably supporting needle 62. Guidance device 108 is otherwise used in
the same manner as guidance device 20.
The guidance devices disclosed herein may easily be manufactured from
molded plastic components and are easily assembled. The guidance device is
relatively compact and may be packaged and stored in sterile form for
ready access by physicians or other users. The guidance device may be
quickly and easily locked at the desired angle. Since the guidance device
disclosed herein is manually supported, the user can quickly position the
guidance device for use adjacent the patient's body without the need to
adjust a series of cranks, bearings, or arms in order to make the needle
insertion.
Those skilled in the art will now appreciate that a guidance device has
been described to facilitate C.T. guided biopsy and fluid drainages in an
accurate, easy and relatively prompt manner. While the invention has been
described with reference to preferred embodiments thereof, the description
is for illustrative purposes only and is not to be construed as limiting
the scope of the invention. For example, while the guidance device
described herein is described for use specifically with C.T. scanners,
those skilled in the art will appreciate that it may also be useful for
ultrasound and magnetic resonance scanning as well. In addition, while a
circular bubble level is preferred, one or more linear levels may also be
used to confirm that the longitudinal axis of the base and/or the pivot
axis are horizontal. Various modifications and changes may be made by
those skilled in the art without departing from the true spirit and scope
of the invention as defined by the apended claims, wherein the term
catheter is intended to broadly designate biopsy needles, drainage
catheters, or any other form of medical needle or tube.
* * * * *
|
|
 |
|
 |
Description |
|
