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Claims  |
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I claim:
1. A stereotactic device for allowing a user to accurately introduce a
medical device through a sterile field into a body at a preselected angle
comprising:
a. a base having an upper surface exposed when the stereotactic device is
in use and a lower surface for placement on the body into which the
medical device is to be introduced, said base having an opening therein,
through which the part of the medical device to be placed within the body
can pass unobstructed.
b. a leg normal to the base, affixed thereto and having a radial slot
therein;
c. a carrier for the medical device comprising:
i. a radial portion which rides within the radial slot;
ii. retaining means for retaining the medical device in a fixed radial
position relative to the arc defined by the radial slot and downwardly
through the opening in the base; and,
iii. means for locking said carrier at a fixed position on the arcute
pathway formed by the slot;
d. markings on said leg along said radial slot for placement of the
retaining means at a preselected point along said radial slot whereby the
medical device retained thereby can be extended downwardly through the
opening and into the body at a preselected angle; and
e. markings on the base of said device for orienting said base, said base
having opposing edges contiguous with the upper surface thereof and normal
to the leg which edges are beveled and slope downwardly and outward from
the surface of the base, said markings on said base comprising markings on
said beveled edges.
2. The stereotactic device of claim 1, wherein the device is T-shaped and
the leg of said device divides said base into a first part delimiting the
sterile field and a second part remote from the sterile field and
separated therefrom by said leg, said stereotactic device further
characterized in that there are markings on the base of said device for
orientation of said base on the body.
3. The stereotactic device of claim 2, wherein a leveling means is
associated with the device to assist in orienting the longitudinal axis of
the base horizontally.
4. The stereotactic device of claim 3, wherein the leveling means is a
circular bubble level on the upper surface of the base.
5. The stereostatic device of claim 1, wherein the angle of the bevel, at
the opposing edges, is from about 15.degree. to about 75.degree..
6. The stereotactic device of claim 1, wherein the base is made of a
transparent material, the markingse are on the upper surface of said base
and the markings run along at least a portion of the length of the upper
surface of the base in parallel with the leg.
7. A stereotactic medical device for accurate placement of a medical
instrument through a sterile field into a body at a preselected angle in a
plane of horizontal or sagittal orientation comprising:
a. a stereotactic bridge comprising:
(i) a span;
(ii) stanchions supporting said span;
(iii) means for moving said span vertically up and down said stanchions;
(iv) means for moving said stanchions horizontally;
(v) means for axially rotating the span in correlation with the angulation
of a C.T. scanner to enable sagittal insertion of the medical device;
b. a guidance device for accurate introduction of a part of a medical
device of a given length into said body, said device comprising:
(i) a base comprised of a plate and an upstanding leg positioned
substantially perpendicular to the plate, said plate on one side of said
upstanding leg having a cutout opening delimiting the sterile field
through which a lower part of the medical device can pass unobstructed to
a predetermined position and on the other side of said upstanding leg,
said plate having a means for connecting said guidance device to said span
of said stereotactic bridge, said leg comprised of an arcuate track with
means therealong for indicating a plurality of preselected angles relative
to the predetermined position which is accessible through the opening in
the plate; and
(ii) a carrier including means for movement along the arcuate track, means
for retaining the medical device in a fixed position relative to the
riding means, and means for locking the retaining means at one of the
preselected angles relative to the predetermined position;
whereby the lower part of the medical device-retained by the carrier can be
extended through the opening in the plate and into the predetermined
position at said one of the preselected angles;
c. means for moving and locking the guidance device defined in "b" along
the length of said span, said means including said means for connecting
said guidance device to said span of said stereotactic bridge; and
d. means for leveling the guidance device after the guidance device is
connected to the span.
8. The medical device of claim 7, wherein said leveling means is a leveling
bubble on the guidance device on the span.
9. The medical device of claim 8, wherein the axis of rotation of the span
pivots on a centerline which intersects the point of entry of the medical
device into the body.
10. The medical device of claim 7, wherein the arcuate track is an arcuate
slot of a given width cut through said leg and the means for movement
along the arcuate track comprises a means for riding within the arcuate
slot cut through the leg.
11. The medical device of claim 10, wherein the axis of rotation of the
span pivots on a centerline which intersects the point of entry of the
medical device into the body.
12. The medical device of claim 7, wherein the axis of rotation of the span
pivots on a centerline which intersects the point of entry of the medical
device into the body.
13. The medical device of claim 7, wherein the axis of rotation of the span
pivots on a centerline which intersects the point of entry of the medical
device into the body.
14. A stereotatic medical device for accurate placement of a medical
instrument through a sterile field into a body at a preselected angle in a
plane of horizontal or sagittal orientation comprising:
a. a stereotactic bridge comprising:
(i) a span;
(ii) stanchions supporting said span;
(iii) means for moving said span vertically up and down said stanchions,
said means for moving said span vertically up and down including a negator
spring for facilitating said vertical up and down movement;
(iv) means for moving said stanchions horizontally;
(v) means for axially rotating the span in correlation with th angulation
of a C.T. scanner to enable sagittal insertion of the medical device;
b. a guidance device for accurate introduction of a part of a medical
device of a given length into said body, said device comprising:
(i) a base comprised of a plate and an upstanding leg positioned
substantially perpendicular to the plate, said plate on one side of said
upstanding leg having a cutout opening delimiting the sterile field
through which a lower part of the medical service can pass unobstructed to
a predetermined position and on the other side of said upstanding leg,
said plate having a means for connecting said guidance device to said span
of said stereotactic bridge, said leg comprised of an arcuate track with
means therealong for indicating a pluarlity of preselected angles relative
to the predetermined position which is accessible through the opening in
the plate; and
(ii) a carrier including means for movement along the arcuate track, means
for retaining the medical device in a fixed position relative to the
riding means, and means for locking the retaining means at one of the
preselected angles relative to the predetermined position;
whereby the lower part of the medical device retained by the carrier can be
extended through the opening in the plate and into the predetermined
position at said one of the preselected angles; and
c. means for moving and locking the guidance device defined in "b" along
the length of said span, said means including said means for connecting
said guidance device to said span of said stereotactic bridge.
15. A stereotactic medical device for accurate placement of a medical
instrument through a sterile field into a body at a preselected angle in a
plane of horizontal or sagittal orientation comprising:
a. a stereotactic bridge comprising:
(i) a span;
(ii) stanchions supporting said span;
(iii) means for moving said span vertically up and down said stanchions;
(iv) means for moving said stanchions horizontally;
(v) means for axially rotating the span in correlation with the angulation
of a C.T. scanner to enable sagittal insertion of the medical device;
b. a guidance device for accurate introduction of a part of a medical
device of a given length into said body, said device comprising:
(i) a base comprised of a plate and an upstanding leg positioned
substantially perpendicular to the plate, said plate on one side of said
upstanding leg having a cutout opening delimiting the sterile field
through which a lower part of the medical device can pass unobstructed to
a predetermined position and on the other side of said upstanding leg,
said plate having a means for connecting said guidance device to said span
of said stereotactic bridge, said leg comprised of an arcuate track with
means therealong for indicating a plurality of preselected angles relative
to the predetermined position which is accessible through the opening in
the plate; and
(ii) a carrier including means for movement along the arcuate track, means
for retaining the medical device in a fixed position relative to the
riding means, said retaining means comprising a pair of arms with threaded
bores therethrough and spaced from each other at a distance less than the
given length of the medical device so that said medical device can be held
securely in the bores thereof, and means for locking the retaining means
at one of the preselected angles relative to the predetermined position;
whereby the lower part of the medical device retained by the carrier can be
extended through the opening in the plate and into the predetermined
position at said one of the preselected angles;
c. means for moving and locking the guidance device defined in "b" along
the length of said span, said means including said means for connecting
said guidance device to said span of said stereotactic bridge.
16. The medical device of claim 15, wherein the locking means of the
guidance device includes a threaded fastener means for engaging the
threaded bore through the cylindrical protrusion of the riding means.
17. The medical device of claim 16, wherein the axis of rotation of the
span pivots on a centerline which intersects the point of entry of the
medical device into the body. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a stereotactic device of simplified
structure that is adaptable to align and precisely orient a variety of
medical devices such as differently sized needles, cannulas and guide
wires into the human body for procedures such as tumor biopsies,
percutaneous discectomies, cyst aspirations and tumor localizations. The
device of the present invention is adapted for use in combination with a
stereotactic bridge comprised of a span rotatable on its horizontal axis
and movably affixed to a C.T. scan table or X-ray table by positioning
means. The positioning means allows vertical and horizontal movement of
the span relative to said tables. The embodiment of the present invention
relating to the combination of stereotactic device and bridge provides
enhanced accuracy of placement and orientation of the medical device and
avoids deviation during insertion attributable to hand movement. The
device is interactive with a C.T. scanner to achieve accurate placement of
the oriented medical device. The embodiment of the invention involving the
use of the stereotactic bridge allows alignment of medical devices in
sagittal orientation with a high degree of accuracy. Verification of
positioning using the bridge can be accomplished in a facile manner.
2. Description of the Prior Art
The need for facilitating subcutaneous injections and orienting the
insertion of cannulas or needles with precision in surgical procedures has
given rise to the development of numerous devices adapted for such
purposes.
An early device for facilitating subcutaneous injection is described in
U.S. Pat. No. 3,021,842. A locking ball and socket arrangement is
disclosed which is used for positioning a needle at a desired angle. To
lock the ball in the socket at the preselected angle, the patentee
provided a ball-engaging ring that was threaded on the socket.
More recently, after the advent of C.T. scanning, new devices for orienting
and inserting cannulas or needles have been developed.
C.T. scanners are commonly used to provide doctors with cross-sectional
internal pictures of a patient. Through the use of C.T. scanner
technology, physicians are able to accurately place biopsy needles and
drainage catheters into preselected areas of the body with a high degree
of success.
C.T. scanners 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.
A hand-held needle guidance device which is suitable to accurately and
easily use C.T. generated information to position a biopsy needle or
drainage catheter relative to a patient's body is described in U.S. Pat.
No. 4,733,661. The described guidance device utilizes a needle support arm
hinged at the end of a planar base. The arm is oriented by protractor
means also situated at the hinged end of the base. A wing nut arrangement
is used to lock the pivoting arm at a predetermined angle relative to the
planar base. The planar base is horizontally oriented by a circular bubble
level on the base.
In apposition to the simple hand-held guidance device of U.S. Pat. No.
4,733,661, one finds in the art highly complex C.T. scanner guided
stereotactic brain surgery devices utilizing skull mounted frames with
associated complex positioning instruments. Such instruments, as pointed
out in U.S. Pat. No. 4,733,661, are well-known in the art, such art being
well referenced in U.S. Pat. No. 4,733,661.
A C.T. scanner guided stereotactic brain surgery instrument described in
U.S. Pat. No. 4,350,159 is used to precisely insert an electrode in the
brain of a patient for treatment of nervous disorders. The orientation of
the inserted electrode at an angle to the plane formed by the frame is
achieved utilizing a semicircular rotatable arc mounted on the frame onto
which a movable electrode carrier can be locked. A separate protractor is
used to orient the electrode carrier. For drilling the hole through which
the electrode is inserted, the arc is rotated part of the way.
SUMMARY OF THE INVENTION
The present invention achieves movement of a medical device along an arc
defined by an arcuate slot/opening in a protractor which operates as a
means of both orienting and supporting a carrier which rides within the
slot. The carrier can be locked into position along the arc defined by a
slot at any preselected angle.
In accordance with the present invention, a T-shaped or L-shaped
stereotactic device of simple structure allows a user to accurately
introduce a medical device within a body at a preselected angle. The
device is adapted for interactive use with a C.T. scanner and on a patient
horizontally supported on the surface of a C.T. scan table. In one
embodiment of the invention, the stereotactic device comprises a base
having an upper surface exposed when the stereotactic device is in use and
a lower surface placed on the body into which the medical device is to be
introduced. The base has an opening therein, through which the part of the
medical device to be placed within the body can pass unobstructed. The
opening may be of any shape or size, provided that the instrument inserted
into the patient can be accommodated. The opening defines the sterile
field through which the medical device is inserted and therefore the size
and placement should be appropriate for the use intended. In one
embodiment of the invention, adapted to facilitate disengagement and
removal of base and leg from the medical device, the opening in the base
is formed by cutting out a portion of the base. Such opening is herein,
alternatively, referred to as the cutout, cutout portion/opening or
cephalic opening, the latter being a coined term referring to an opening
in the base that begins at an edge of the base and is open toward the
gantry of the C.T. scanner. This opening delimits the sterile field. The
term "opening" includes the completely open side of the L-shaped device
where the sterile field is delimited by the leg and base thereunder. By
using a cutout as the opening, the stereotactic device can be removed by
disengaging the carrier for the medical device and removing the
stereotactic device away from the locus of insertion in a horizontal
direction. A wall normal to the base, suitably the leg of a T-shaped
aluminum bar, having an arcuate slot therein, defines a circular segment
for angular orientation. The stereotactic device has a carrier for the
medical device which is comprised of an arcuate portion which rides within
the arcuate slot; retaining means for retaining the medical device in a
fixed radial position relative to the arc defined by the arcuate slot and
downwardly through the opening in the base; and, means for locking said
carrier at a fixed position on the arcuate pathway formed by the slot.
There are markings on the wall along said arcuate slot for placement of the
retaining means at a preselected point along said arcuate slot whereby the
medical device retained thereby can be extended downwardly through the
opening and into the body at a preselected angle. There are also markings
on the surface and/or edges of said base for orientation of said base on
the body.
Where linear markings are utilized to align the stereotactic device of the
present invention, suitably one or more marks are scribed on the upper
surface of the base and run along at least a portion of the length of the
upper surface of the base in parallel with the wall. If extended across
the base opening, the extended scribe mark/line would intersect the radial
line defined by the pathway through which the medical device, e.g., a
needle, is oriented. The linear scribe marks are particularly helpful in
alignment of the stereotactic device where the base is made of a
transparent material, e.g., a clear plastic such as one of the
polycarbonates. Such plastics are among the materials which meet the
structural requirements of the stereotactic device of the present
invention and can withstand conditions of sterilization.
It has been found that alignment of the stereotactic device using markings
on top of the base, can be facilitated if the edges of the base are
beveled. Thus, the edges intersecting the plane formed by the transverse
light source of the C.T. scanner are preferably beveled. In accordance
with the embodiment of the invention involving beveling the edge of the
base, the marking on the top of the base which is used to orient the
stereotactic device, extends angularly within the plane of the image
cross-section.
Accordingly, the alignment of the stereotactic device on the laser light
beam reference line replicated on the patient can be readily confirmed by
the physician by reference to the opposite marked ends. The markings at
each end should fall on the reference line on the patient. Where a
metallic base, suitably aluminum or some other nontransparent material, is
used to fabricate the stereotactic device, beveling of the ends is much
preferred, since alignment using the markings at the edges of the bases is
facilitated where the mark can be placed adjacent to the reference line.
Where the retaining means is adapted to accommodate a series of differently
sized devices, e.g., needles, a series of markings are suitably used, with
one marking for orienting the pathway of each needle of varying size.
The center of the circle formed by extending the arcuate segment defined by
the arcuate opening should be at a point in the plane formed by the bottom
surface of the base.
A leveling means may be associated with the device to aid in orienting the
longitudinal axis of the base horizontally. The leveling means suitably is
a circular bubble level on the upper surface of the base. The site of the
level is preferably situated on top of the horizontal base, on the side of
the base extending outwardly from the surface of the leg facing away from
the sterile field. The linear markings on the upper surface of said base
suitably run along at least a portion of the length of the upper surface
of the base in parallel with the surface of the leg. Preferably, the
markings extend to the opposed edges of the base normal to the leg. Such
edges are most preferably beveled to facilitate alignment of the
stereotactic device using a reference line on the patient.
The present invention, as previously noted, is a guidance device for
allowing a user to accurately introduce a medical device to a preselected
point in a patient's body. The stereotactic device comprises a base
including a plate to be placed on and/or supported by the patient's body
and an upstanding leg positioned substantially perpendicular to the plate.
The plate has an opening through which a lower part of the medical device
can pass unobstructed into a predetermined part of the patient's body. The
leg has an arcuate slot of a given width cut therethrough and is marked to
indicate a preselected angle relative to the predetermined part of the
patient's body which is accessible through the opening in the plate. A
carrier, which rides within the arcuate slot cut through the leg of the
base, carries a means for retaining the medical device in a fixed position
relative to the riding means and a means for locking the retaining means
at one of the preselected angles relative to the predetermined part of the
patient's body. The riding means may be a cylindrical protrusion having a
threaded bore therethrough and an outer diameter slightly less than the
given width of the arcuate slot cut through the leg. Preferably, the
retaining means is comprised of a pair of arms with threaded bores
therethrough, spaced from each other at a distance less than the given
length of the medical device to assure that said medical device can be
held securely in the bores thereof. The locking means typically is
comprised of a threaded fastener for engaging the threaded bore through
the cylindrical protrusion of the riding means.
One aspect of the present invention comprises the use of the
above-described stereotactic device in combination with a stereotactic
bridge. The stereotactic bridge functions to both steady the stereotactic
device and to assure alignment of the leg wall of the stereotactic device
parallel to the plane described by the tomographic cut image.
The stereotactic bridge is adapted for affixation to patient tables
typically used for positioning a patient in the gantry of a C.T. scanner
or relative to an X-ray machine.
In one embodiment of the invention, stereotactic device placement is
facilitated by using same in combination with a stereotactic bridge. The
stereotactic bridge is comprised of stanchions and a span which overlies
the patient. The span is used to support the stereotactic device. The span
can be rotated axially, to orient the medical device carried along the
arcuate track of the leg of the stereotactic device so that the part
inserted into the patient is within the plane of the tomographic cut of
the C.T. scanner. The tomographic cut image generated by the C.T. scanner
is used to develop the locus of entry and angle of insertion of the
medical device. The wall of the leg of the stereotactic device which
carries the medical device must be in a plane parallel to the plane of the
tomographic cut in order to ensure accurate placement of the medical
device.
The stereotactic bridge is comprised of positioning means for positioning
the stereotactic device relative to the patient.
The span of the stereotactic bridge is movable in a horizontal plane both
towards and away from the gantry. Described in terms relative to the
patient's torso, the horizontal movement is from head to foot, although
the limits of horizontal movement need not traverse the entire length of
the torso.
The means employed for horizontal movement may comprise a slide and guide
arrangement along the side of the C.T. scan table. The horizontal guide,
typically a metal rail, is parallel to the C.T. scan table surface and is
affixed to the fixed support on which the movable table top of the C.T.
scan table is carried. The patient is placed on the movable table top in
the appropriate position for the medical procedure. The movable table top
is used to move the patient into and away from the gantry of the C.T.
scanner.
The bridge is movable in a vertical direction to rest the table on the
patient's torso at the appropriate height.
The means employed for horizontal movement may comprise a slide and guide
array of any configuration and suitably may be square, round or some other
shape.
The stereotactic device which rides on the span and can be locked in
position at a given point along the length of the span is thus movable
side-to-side relative to the patient's torso.
The means employed for side-to-side movement may comprise a slide and guide
array of any configuration, square, round or some other shape or any form
of suitable track for movement for movement of the stereotactic device
across the patient's body.
The sliding elements of the horizontal, vertical and side-to-side movement
means suitably include means for securing the slides in the required
positions. Locking means such as set screws, wing bolts, simple mechanical
elements, can be used among others as slide/track locks. The stereotactic
bridge architecture is chosen to achieve movement and positioning using
simple and reliable mechanisms and the details of specific machine
elements selected are such as would be appreciated by one skilled in the
art.
In one specific embodiment of the present invention, the stereotactic
device includes a guide attachment integral therewith that is comprised of
a slide which rides on the span of the stereotactic bridge. Such
side-to-side guide and slide arrangement provides the most elementary
side-to-side positioning means for the stereotactic device carried by the
bridge.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective of the embodiment of the invention involving in
combination the stereotactic device and bridge.
FIG. 2 is a sectional view taken along 2--2 of FIG. 1.
FIG. 3 is a top view of FIG. 2.
FIG. 4 is a partial view of the top portion of the stanchion illustrating
the negator spring and the rider on the stanchion rails including the nob
which is used to adjust the sagittal angle and the camlock.
FIG. 5 illustrates a simplified and alternative embodiment of the combined
stereotactic device and stereotactic bridge as illustrated in FIG. 8
(perspective view).
FIG. 6 is a front view of the device in use showing a partial cross-section
of the torso to illustrate insertion of the needle to a fixed point.
FIG. 7 is a perspective view of a further embodiment of the stereotactic
device illustrating the relationship of the needle holder and cutaway
portion delimiting the sterile field.
FIG. 8 is a front view illustrating the front view of FIG. 7 with the
needle in use being inserted vertically.
FIG. 9 is a side view of FIG. 8.
FIG. 10 is an end view illustrating an alternative embodiment using a
rectangular span.
FIG. 11 is a partial section taken from FIG. 10.
FIG. 12 is a further embodiment of the invention wherein the L-shaped
stereotactic device is illustrated in perspective.
FIG. 13 is a top plan view of FIG. 12 affixed to the span.
FIG. 14 is an end view of FIG. 12.
FIG. 15 is a partial view taken from 14 illustrating the use of various
sized needles.
DETAILED DESCRIPTION OF THE DRAWINGS
In FIG. 1, a preferred embodiment of the invention is shown wherein the
stereotactic medical device of the present invention comprising a guidance
device 10 is carried, oriented and stabilized by a stereotactic bridge.
The stereotactic bridge is comprised of span 100, carried by two
stanchions 150, 150'. The bridge is movable horizontally along the length
of a C.T. scan table T using a rail guide 160 on which slide 165
supporting linear bearings 130 and 130' is carried. Toggle clamp 166 locks
slide 165 in position after horizontal positioning.
Span 100 is movably carried on stanchions 150, 150' by span support members
120, 120'. Vertical positioning of the span is achieved by sliding the
span support members up and down the linear bearings of the stanchions
150, 150'. Up and down movement of span 100 is facilitated by use of a
negator spring (spring balancer) 145 attached to the span support members
by a retractor cord 111.
Positioning side-to-side across the width of the body/table is achieved by
moving guidance device 10 which is carried in slot/groove 110 lengthwise
along span 100.
A simple means of carriage and affixation in locked position is illustrated
in FIG. 2, where thumbscrew 118 is shown in locking engagement with the
base 15 of guidance device 10. As best illustrated in FIG. 3, thumbscrew
118 serves the dual purpose of carrier as well as locking means, sliding
along slot 110 of span 100.
In FIG. 4, one of the span supports 120 is shown. Toggle clamp 170 is used
to lock the span in position on vertical bearing 130'. For this purpose, a
more simple arrangement, such as a thumbscrew or other alternatives, is
suitable.
Knob 140, which is attached to span 100, is used to rotate the span 100
axially. The mechanism for axial rotation can be chosen from any of the
typical arrangements allowing angular adjustment. Thus, for this purpose
one may use a mechanism rotatable by means of a knob affixed to a shaft
passing through the span support and connected to the bridge.
The specific mechanism and markings for achieving and measuring axial
rotation are matters of choice; however, it should be underscored that, in
the preferred embodiment of the present invention, where the stereotactic
medical device of the present invention is to be used for sagittal
introduction, as shown in FIG. 2, the axis of rotation of the span should
pivot on a centerline which intersects the point of entry 13 of the
medical instrument into the body. This feature is illustrated by reference
to the two positions of guidance device 10, A and B, one of which (B) is
shown in shadow with the angulation pattern represented by arrow 11. As
also shown in FIG. 4, a leveling device, bubble 60, may be used to verify
horizontal reference of the stereotactic bridge.
FIG. 5 illustrates a most simple embodiment of the present invention where
the guidance device 10 is carried on a span 200 made from a cylindrical
rod; and, where cylindrical rods are used for stanchions. As can readily
be appreciated, the stability of this simplified embodiment of the
invention suffers because of the potential for movement of the stanchion
arrangement if care is not exercised by the user.
In FIG. 7, one of the preferred structures of the guidance device
(stereotactic device) 10 is shown. The device is T-shaped and comprised of
base 15 and leg 30 normal thereto.
Leg 30 has a radial slot 12 therein in which radial portion 22 of carrier
20 rides. Marking 14 along radial slot 12 and marking 22 on carrier 20 are
used for radial alignment of the carrier. Apertures 21, 23 and 25 and 21',
23' and 25' are used to retain a needle 98 of syringe 99 along its length
in a fixed position on the carrier. Placement of the holes is away from
the leg and over the cutout portion indicated generally by numeral 50.
This cutout portion likewise denotes generally the sterile field. The
stereotactic device illustrated in FIG. 7 has beveled edges 17, 17' and
markings 31, 33, 35 for aligning the device on the body.
In FIG. 8, needle 99 is shown in position on carrier 20 with the cannula
passing therethrough and after insertion using stereotactic device 10. The
position shown in FIG. 8 is that used where a vertical orientation is
required. Insertion is illustrated in FIG. 6. A portion of span 200 of the
stereotactic bridge is also shown.
Reference to FIGS. 9 to 11, inclusive, illustrates the use of a thumbscrew
24 to lock the carrier 10 in place along slot 12, the threaded portion 26
of thumbscrew 24 being shown in FIG. 9. A thumbscrew 18 lock mechanism
from a cylindrical span member is passed through slide member 16 is
illustrated in FIG. 9. In FIGS. 10 and 11 an alternative slide member 16'
for use with a square-shaped rod 300 and a thumbscrew 18' for locking
member 16' onto rod 300 is illustrated. Placement of bubble leveling means
60 on the stereotactic device is illustrated in FIG. 10.
FIG. 12 illustrates the L-shaped configuration of guidance device 10 in
which the base 15 does not extend (is entirely cutout) on the sterile side
of protractor leg 30. This embodiment is particularly suitable for
sagittal orientation where any outcropping of the base on the sterile
field side of the leg 30 would impede/interfere with axial rotation of the
bridge and guidance device. FIGS. 13 through 15 illustrate further, using
alternative views, the guidance device 10 of the present invention with
FIG. 15 indicating an adaptation of carrier 20 allowing the same carrier
to be used for a variety of syringes of differing diameter as shown by
reference to needles 99a, 99b and 99c.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Use of the Stereotactic Device in C.T. Guided Discectomy (Hand-Held Mode)
A C.T. scan is made of the suspected disc herniation. The patient is placed
in the prone position on a scanning table, prepped, and draped in the
usual manner.
The point of entrance of the selected site in the skin, as well as the
depth and the angle to be used, is calculated under C.T. guidance in a
manner well known to the art as follows:
The table top carrying the patient is moved into the gantry and thin 3-5 mm
axial tomographic cuts are obtained by C.T. scan through the herniated
disc.
The best tomographic cuts is selected and a transverse light beam line
identical to the tomographic cut with an X-ray beam is made on the patient
and marked on the skin with a colored line.
The point of entrance is marked with a needle and determined by the C.T.
scan. The depth and angle are determined by C.T. scan guidance.
Local anesthesia is administered in the skin, muscles, and paravertebral
space. A three (3) mm skin incision is made at the selected point of entry
of the flex trocar.
Using the stereotactic device for proper guidance of the trocar, the
physician inserts the flex trocar slightly posteriorly into the nucleus
pulposus of the herniated disc. The stereotactic device is placed on the
patient and is oriented so that the trocar is introduced into the body in
the plane of the cross-section image developed by the C.T. scanner. This
requirement is achieved by aligning the appropriate marking on the
stereotactic device (in the plane of trocar travel) with the colored line.
The colored line is a reference line drawn on the patient that is within
the vertical plane viewed by the C.T. scanner. A marked trocar is used.
Such trocars are marked along their length so that the depth of insertion
is readily controlled by observing the reference markings and by inserting
the same to the predetermined depth by reference to said markings. The
proper position of the flex trocar is verified by C.T.
Prior to verification, it is a simple matter, in view of the facile
arrangement for disengaging the carrying means, to disengage the carrier
and carried medical device from the arcuate slot of the stereotactic
device.
A straight cannula with a tapered dilator is passed over the flex trocar
and inserted down to the wall of the annulus. The position of the cannula
and the position of the flex trocar is again verified by C.T.
Incision is made of the annulus by the trephine, and then the trephine and
flex trocar are removed from the cannula.
The nucleotome probe is inserted through the cannula into the nucleus
pulposus, and correct position is verified by overhead films on the C.T.
scan table.
Suction of the annulus pulposus is performed for approximately 25 minutes,
and the patient returns home the same day of the procedure.
Use of The Stereotactic Device In Combination With The Stereotactic Bridge
(Stereo-Tactic Bridge Supported Mode)
The patient is placed on the C.T. scan table in the prone position. The
lumbar region is prepped and draped in the usual manner.
The table top carrying the patient is moved into the gantry and thin 3-5 mm
axial tomographic cuts are obtained by C.T. scan through the herniated
disc.
The best tomographic cut is selected and a transverse light beam line
identical to the tomographic cut with an X-ray beam is made on the patient
and marked on the skin with a colored line.
The point of entrance is marked with a needle and determined by the C.T.
scan. The depth and angle are determined by C.T. scan guidance.
The table top carrying the patient is removed from the gantry. The position
of the patient on the table top should not be changed in order to maintain
the torso in t | | |
