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Description  |
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BACKGROUND OF THE INVENTION
The present invention relates to a biopsy guide in which surgical devices
can be accurately positioned relative to an image.
A variety of devices have previously been used during surgery to position a
patient in an operating room and so that the position of a particular
location on a patient can be accurately located.
U.S. Pat. No. 4,617,925 to Laitinen discloses an adaptor for definition of
the position of brain structures. This is implemented using spatial
coordinates in computerized tomography and NMR examination and
transferring the coordinates to a stereotactic apparatus. The adaptor
includes supports for holding a patient's head in place.
U.S. Pat. No. 4,386,602 to Sheldon et al. relates to an intracranial
surgical operative apparatus. The apparatus in this patent is used for
operating on the brain with minimal disturbances.
U.S. Pat. No. 4,465,069 to Barbier et al. relates to the cranial insertion
of a surgical needle utilizing computer-assisted tomography.
U.S. Pat. No. 5,257,998 to Ota et al. relates to a medical
three-dimensional locating apparatus capable of accurately reproducing the
three-dimensional position data of a focus obtained through an imaging
diagnosis in an affected part of a patient body for an actual surgical
operation. This patent additionally discusses the selection of an optimum
approach angle of a direction to approach the focus point along a
reference line through a simple operation.
U.S. Pat. No. 4,592,352 to Patil discloses a computer-assisted tomography
stereotactic system. The system disclosed in the Patil patent discloses an
apparatus for performing surgical procedures through a patient's skull to
a target within the skull using a computer-assisted tomography scanner.
U.S. Pat. No. 4,602,622 to Bar et al. discloses a computer tomography
apparatus producing transverse layer images. A patient-targeting device is
used to introduce a biopsy needle into a patient along a path determined
by the targeting device.
U.S. Pat. No. 4,638,789 to Shelden et al. discloses a stereotactic method
and apparatus for locating and treating or removing lesions. The apparatus
defines points in a region using a three-dimensional coordinate system
with reference to a ring attached to the patient to establish a reference
point for the three-dimensional coordinate system at the center of the
ring.
U.S. Pat. No. 5,387,220 to Pisharodi discloses a stereotactic frame and
localization method incorporating localization frames which is operable
without the use of head pins or screws. Several natural cranial reference
points are initially established. Once the natural reference points are
established, localization is performed using a spherical coordinate system
incorporating lines, planes and angles referenced on and within the head.
U.S. Pat. No. 5,280,427 to Magnusson et al. discloses a puncture guide for
computer tomography. A needle of a tissue sampling device is guided to a
target location within the body of a patient. The biopsy needle is
directed along a desired path and the depth of penetration of the needle
is controlled to prevent accidental overpenetration of the needle. The
guidance device is not limited to the plane perpendicular to a
longitudinal axis of the patient but is also capable of guiding the needle
in a plane which is neither perpendicular or parallel to the longitudinal
axis.
Previous guiding devices are difficult in providing an image guided
surgical system which may be used during surgery without complicated
coordinate system calculations.
SUMMARY OF THE INVENTION
The present invention relates to a surgical guiding arrangement in which a
surgical instrument may be positioned accurately relative to a target
point and an entry point of the patient and along a trajectory line
through the entry point and target point of the patient.
A surgical platform is first moved along a guiding arm arc close to a point
along the trajectory extending through the entry point and the target
point of the patient. This position on the trajectory line is any point
external to the patient's head. Prior to sliding of the surgical platform
along the guiding arm, the patient's head is fixed rigidly to a head clamp
which is fixed to an operating table. The guiding arm arc swivels, for
example, about two joints at one end of the guiding arm. Once the guiding
arm arc is moved into a position so that a portion of the guiding arm arc
is near the entry point and/or trajectory line, the guiding arm arc is
locked in position. Then the surgical platform is moved along the guiding
arm arc until the surgical platform is near the trajectory line. The
surgical platform is then locked to the guiding arm arc. A metal plate
within the surgical platform is then moved in two dimensions until a ball
joint pivot point at the middle of the metal plate is at a point along the
trajectory line. The metal plate is then locked in place. The ball joint
is then rotated so that the surgical sleeve extends exactly along the
trajectory line. In this manner, the two dimensional translation of the
surgical platform is completely separated from the two dimensional
rotation of the ball joint. The surgical sleeve is moved into position
along the trajectory line extending between the entry point and the target
point on the patient's head without any complicated calculations being
required.
The navigational software allows the surgeon to accurately move the pivot
point to a point along the trajectory line while looking at an image
comparing the position of the pivot point with a position on the
trajectory line. Then, the navigational software allows the surgeon to
view on the image the difference between the angle of the surgical sleeve
relative to the trajectory line until the surgical sleeve is lined up
exactly along the trajectory line.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates an arrangement according to an embodiment of the present
invention.
FIGS. 2 and 3 illustrates arrangements within a surgical platform according
to an embodiment of the present invention.
FIG. 4 illustrates separate translational and rotational movements
according to an embodiment of the present invention.
FIG. 5 illustrates an arrangement according to an embodiment of the present
invention.
FIG. 6 illustrates an arrangement according to an embodiment of the present
invention.
FIGS. 7, 8, 9, 10 and 11 illustrate relative arrangements between an
attachment arm and a guiding arm according to embodiments of the present
invention.
FIG. 12 illustrates an arrangement between a surgical platform and a needle
guide according to an embodiment of the present invention.
FIGS. 13 and 14 illustrate portions of a surgical platform according to an
embodiment of the present invention.
FIGS. 15, 16, 17 and 18 illustrate needle guide arrangements according to
embodiments of the present invention.
DETAILED DESCRIPTION
In a surgical device system (or biopsy device system) according to an
embodiment of the present invention, a neurosurgeon selects an "entry"
point and a "target" point in a preoperative image volume (e.g., CT or
MR). The target point is the point the neurosurgeon wishes to reach, e.g.,
to obtain a sample of tissue or implant an electrode. The entry point is
the point on the skull that the neurosurgeon wishes to go through to reach
the target point. The entry point and the target point together define a
"trajectory," (i.e., the line passing through these two points). The
general purpose of the surgical device (biopsy device) is to direct a
surgical needle (such as a biopsy needle or electrode or whatever) such
that it passes through the entry point and stops at the target. Biopsy
devices are an integral part of most stereotactic frame systems. The
biopsy device according to the present invention may be used for any
frameless image-guided surgical navigation systems.
The first step in the surgical guide system (biopsy guide system) according
to an embodiment of the present invention, is getting a surgical platform
(biopsy car or biopsy platform) close to the trajectory. One embodiment
uses a guide arm arc and a biopsy car that slides along the guide arm arc.
The patient's head is rigidly fixed in a head clamp such as a
Mayfield.RTM. head clamp. The head clamp is affixed to an operating table.
The arc is rigidly attached to the head clamp. Alternatively, the arc
could instead be attached to the operating table or to something else
rigidly attached to the table. In one embodiment, the arc swivels about
its two joints at one end. Alternatively, the arc could swivel about its
two ends. The biopsy platform is connected to the biopsy car that slides
along the arc. With these various degrees of freedom, the biopsy platform
can be placed over a wide region of the head.
It is noted that frame-based surgical devices (biopsy devices) typically
work with a specific geometrical design (e.g., a circular arc with a
specific radius). The image coordinates of the entry and target points are
converted to physical space coordinates, and these are converted to a set
of biopsy device parameters (e.g., arc angles and position along the arc).
Thus, frames-based biopsy devices require the arc to be carefully
constructed and calibrated. In the present invention, the arc serves as a
device to get the biopsy platform close to the trajectory, and thus does
not need to be as carefully constructed. The primary requirement of the
arc is that it be mechanically sturdy. In fact the present invention could
be implemented without an arc, although it may be the easiest way to
manufacture a mechanically solid support. Another approach according to an
embodiment of the present invention, is to have the biopsy platform
connected to a multi-jointed arm that is in turn rigidly attached to the
head clamp or the operating table.
In one embodiment of the present invention, the biopsy platform consists of
a movable metal plate sandwiched within an annular metal support. The
metal plate can be locked in place with a set screw, for example. A ball
joint is located in the center of the metal plate. A biopsy sleeve passes
through the middle of the ball joint and can accommodate both an
intraoperative localization device (ILD) and a biopsy guide. The ball
joint can be locked in place with a set screw. In one embodiment of the
present invention, the biopsy platform is connected to the biopsy car with
a screw. The biopsy platform can be moved by loosening the screw.
After getting the biopsy platform close to the trajectory, the position of
a pivot point and orientation of the biopsy sleeve is set as follows. The
pivot point is located at the center of the ball joint. First, the present
inventors have recognized that it is not necessary to be at the entry
point (e.g., of the body) but rather need only be on the trajectory.
Second, it is recognized that position and orientation may be decoupled.
Because it is necessary to be on the trajectory rather than at a specific
point on the line, the biopsy sleeve can be positioned with a
two-dimensional (2D) translation of the biopsy platform. The biopsy
platform does not need to be perpendicular to the trajectory. The ILD is
placed in the biopsy sleeve. In an embodiment of the present invention,
the ILD is a probe connected to a handle with infrared emitting diodes
(IREDs) that are tracked by an optical position sensor (OPS), but which
could also be for other frameless systems different types of devices,
e.g., an articulated mechanical arm, an electromagnetic device, or an
ultrasonic device. The biopsy platform (or metal plate) is moved until the
ILD position, which is calibrated such that it corresponds to the center
of the ball joint (or pivot point), is on the trajectory. When it is on
the trajectory, the metal plate is locked in place.
The proper two-dimensional transitional movement can be accomplished as
follows. An image volume consisting of slices perpendicular to the
trajectory is created. The navigation system converts the physical space
position of the ILD to the image coordinate system. The position of the
ILD relative to the image is displayed on the screen along with the
position of the trajectory in the appropriate image slice. The plate is
moved until the position of the ILD coincides with the position of the
trajectory. Additional information can be provided to make the task
easier, e.g., a zoomed image and/or the distance of the ILD from the
trajectory.
According to one embodiment of the present invention, only gross manual
adjustment of the surgical platform is necessary. Finer control of
movement might be accomplished using screws. In fact, screws for both
coarse and fine position adjustment may be used.
After the ILD position (e.g., the position of the pivot point) is
translated such that it is on the trajectory (and thus the center of the
ball joint is on the trajectory), the ball joint is rotated until the
orientation of the ILD (and thus the orientation of the axis of the biopsy
sleeve) coincides with the orientation of the trajectory. When the proper
orientation is found, the ball joint is locked in place. The proper
orientation can be achieved as follows. An image volume consisting of
slices perpendicular to the trajectory is created. The navigation system
converts the position and orientation of the ILD in physical space to the
position and orientation in the image coordinate system. This information
is used to calculate the intersection of the trajectory of the ILD (and
thus the trajectory of the axis of the biopsy sleeve) with the image slice
that passes through the target and is perpendicular to the desired
entry-target trajectory. The position of both this intersection and the
target is displayed in this slice. The ball joint is rotated until this
intersection coincides with the target. Again, additional information can
be provided to make the task easier, e.g., a zoomed image and/or the
distance of the intersection from the target. Additionally, in one
embodiment of the present invention, the slice passing through the target
is displayed. However, any image slice could be displayed according to
other embodiments of the present invention.
After the proper translation of the biopsy platform (metal plate) and
rotation of the ball joint is achieved, the distance between the ILD
position (i.e., the position of the center of the ball joint or pivot
point) and the target is calculated by the navigation system software.
Although it is not important to be at a specific point on the trajectory,
it is important to know the location on the trajectory of the pivot point
(i.e., the center of the ball joint). At this point, a variety of tasks
can be performed. A biopsy can be accomplished by placing a biopsy guide
into the sleeve and then using traditional biopsy techniques. The use of
the distance between the pivot point and the target to set a collar or
stop on a biopsy needle is straightforward. It is also possible to perform
an image-guided biopsy. IRED's could be placed on the biopsy needle and
tracked by the optical position sensor (OPS). This implementation is also
extendable to other frameless systems. For example, an ultrasonic
navigation system could be used to accomplish an image-guided biopsy by
placing spark gaps on the biopsy needle.
Many neurosurgery procedures require a precise location of a stable
platform holding the tools used in those procedures. Previous methods of
implementing the stable platform for holding the tools used in such
surgical procedures involved frames which are physically attached to the
patient's head. The ability to attach, detach and re-attach the surgical
platform and/or surgical guide while maintaining a sterile field around
the patient has become very important.
The present invention provides a surgical guide including a surgical
platform that will remain stable under normal surgical conditions and a
guide arm allowing the surgeon to precisely locate the platform using
computer guided feedback. The system is not directly connected to the
patient and is capable of attachment and detachment with no impact on the
integrity of the sterile field.
A surgical guide according an embodiment of the present invention includes
an attachment bar, a guide arm (or arc) and a surgical platform. In biopsy
procedures, a biopsy needle guide is used to provide stability while
tracking the biopsy needle.
An attachment bar is connected to a starburst joint at a base of a
Mayfield.RTM.-type skull clamp (or other type head clamp). The guide arm
(or arc) is connected to one side of the attachment bar. The guide arm
provides support for the surgical platform. The guide arm allows the
surgical platform (or biopsy car) to be positioned on a theoretical sphere
around the patient's head and can be adjusted in at least two ways. The
guide arm can be moved closer to or further from the head by sliding it
along a shaft extension on the attachment arm. The guide arm can also be
rotated around a theoretical center of the head in a manner similar to the
rotation of the visor of a helmet. The guide arm is locked by a knob for
sliding and a lever for rotating independently.
The guide arm sliding and rotating motion can be used to adjust and locate
the correct position of the surgical platform relative to a predetermined
entry point and target point of a patient. The surgical platform (or
biopsy car) can slide and lock along the entire length of the guide arm
arc to provide an additional gross adjustment. The guide arm sliding and
rotating adjustment and the platform sliding and locking adjustment along
the guide arm arc provide three gross (course) adjustments to provide
access to most regions of surgical interest near a patient (for example,
regions of interest on a patient's head).
A surgical platform (or biopsy car) is a surgical platform where the tools
required for the surgical procedure are located. For example, a biopsy
needle may be provided at the surgical platform. A surgeon uses the guide
arm arc as a track and, for example, using rollers to slide along the
guide arm arc, can be locked in a general position to provide a position
for a pivot point ball joint near the entry site of the patient. The
surgical tools are held in the pivot ball joint which can also be adjusted
for a particular desired angular approach to the target site. The surgical
platform includes two fine adjustment or location parameters. As a first
fine adjustment for the guide arm, two sliding surfaces with a locking
lever allow the center of the pivot ball joint to be precisely positioned
on the previously determined approach vector (or trajectory). A second
adjustment contained in the pivot ball joint assembly allows the surgical
tools to be precisely oriented to the correct approach angle. Fine
adjustment of the surgical approach is contained in the pivot ball joint
assembly in Phi, theta and the angle relative to the tangent of the
theoretical sphere.
A needle guide is required for a biopsy application according to an
embodiment of the present application to maintain the planned trajectory
for the entire length of the biopsy needle. The needle guide allows the
surgeon to define the point of the biopsy needle to be tracked with
application software (for example, Acustar.TM. surgical navigation system
software). The end tip of the biopsy needle may be choosen as the working
point or the "working" portion of the needle may be tracked. It is
important for some position along the biopsy needle guide to be tracked to
determine the location thereof. A particularly advantageous location of
the biopsy needle guide to be tracked is the point at which the surgical
tool projects through the pivot ball joint. The ability to define the
point to be tracked minimizes errors that can occur.
A surgeon can then verify the surgical approach trajectory in a visual
manner using a localization guidance system and computer processed image
software. The localization device is attached to the surgical tool in a
well defined manner. The localization device used in an embodiment of the
present invention can be an array of infrared emitting diodes read by a
calibrated sensor.
The present invention provides a sterile surgery field integrity which can
be easily maintained when attaching, detaching, and reattaching the guide
arm and surgical platform for different procedures during one operating
setup. Additionally, the present invention allows easy adjustment of a
guidance system to accommodate different head sizes. Further, the present
invention allows a stable and accurate positioning of the surgical
platform by using a localization guidance system which eliminates the need
to affix the platform to the patient's skull. According to the present
invention, the platform position is adjustable in r, theta and phi
directions. The pivot ball joint can be adjusted in x, y directions and
the needle (surgical tool) can be rotated through a 90 degree cone. This
allows a full coverage of the skull for most surgical procedures. The
present invention additionally allows surgeon definition of the biopsy
needle (or other tool) position to be tracked. Additionally, in
conjunction with an image guided surgical system (for example, Acustar.TM.
navigation software) the defined needle (or other surgical tool) position
can be tracked in real time. The system additionally requires no
calculations to be implemented in the operating room theater when used in
conjunction with an image guided surgical system.
FIG. 1 illustrates an embodiment of the present invention. A biopsy car 10
(or surgical platform) slides back and forth along a guide arm (or arc)
12. Additionally, the arc 12 can rotate at least at one end thereof to
cover large portions of the patient's head 14. The guide arm arc is
attached to an attachment bar (not illustrated in FIG. 1) which can be
attached to a head clamp such as a Mayfield.RTM.-type head clamp attached
to the patient's head 14. The guide arm arc 12 is rotatable (swivel) at
one or both ends thereof so that the guide arm arc 12 passes generally
over a particular area of interest of the patient's head 14. The surgical
platform 10 is slid along the guide arm arc 12 to a particular area of
interest of the patient's head 14. The surgical platform 10 is then locked
down on the arc 12.
FIGS. 2 and 3 illustrate portions of the surgical platform 10 according to
an embodiment of the present invention. FIG. 2 illustrates portions of the
surgical platform from a top view and FIG. 3 illustrates sections of the
surgical platform from a side view. Reference numeral A represents an
annular metal support, reference numeral B represents a movable metal
plate, reference numeral C represents a ball joint (or a pivot point) and
reference numerals D and E represent set screws. Once the surgical
platform (or biopsy car) 10 is locked down on the guide arm arc 12, the
movable plate B is adjusted within the annular metal support A relative to
a target point on the patient's head 14 until the middle of the ball joint
C is on a point of a predefined trajectory line. Set screw D is then used
to lock the movable metal plate B relative to the annular metal support A.
Ball joint C can then be rotated to adjust and access of a surgical device
sleeve along a particular trajectory line. Once the ball joint (pivot
point C) has been adjusted in this matter, set screw E is used to lock
ball joint C in position.
FIG. 4 illustrates a method of adjusting the biopsy platform 22 and a
biopsy sleeve 24 which extends through a ball joint 26 within the biopsy
platform 22 relative to a trajectory 28. Trajectory 28 is a trajectory
line in a pre-operative image, for example, which extends through an entry
point and a target point of the patient's head. The biopsy platform 22
along with the biopsy sleeve 24 and ball joint 26 are translated in a two
dimensional manner so that the ball joint 26 extends through any point
along the trajectory line 28. The point along the trajectory is a point
which is outside the patient's head but is somewhere along trajectory line
28. Once the center of the ball joint 26 has been moved to the trajectory
line 28, the biopsy platform (for example, the metal plate B of FIGS. 2
and 3) is locked into position. Once the original two dimensional
translation of the biopsy platform is performed to extend the center of
the ball joint 26 to a point on a trajectory line 28, an | | |
