U.S. patent application number 16/301439 was filed with the patent office on 2019-09-26 for attachment component, navigation system and method for tracking a surgical instrument.
The applicant listed for this patent is Ortoma AB. Invention is credited to Matts Andersson, Pasi Riihinen.
Application Number | 20190290367 16/301439 |
Document ID | / |
Family ID | 60325319 |
Filed Date | 2019-09-26 |
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United States Patent
Application |
20190290367 |
Kind Code |
A1 |
Andersson; Matts ; et
al. |
September 26, 2019 |
Attachment Component, Navigation System and Method for Tracking a
Surgical Instrument
Abstract
An attachment component for attaching a tracker of a surgical
navigation system to a surgical instrument is disclosed. The
attachment component comprises a body and an instrument interface
attached to the body and configured for detachable attachment of
the attachment component in a predefined position and orientation
to a surgical instrument or implant. A tracker interface is
attached to the body and has a fixed pre-defined shape for
engagement with the tracker interface of the tracker. The
instrument interface is arranged in an un-calibrated position
relative the tracker interface. A navigation system comprises a
tracker with a tracker interface for attachment to the attachment
component. The tracker is configured to report position and
orientation of its tracker interface. A method implements
translation of position and orientation of the tracker into
position and orientation of an instrument.
Inventors: |
Andersson; Matts; (Lerum,
SE) ; Riihinen; Pasi; (Molndal, SE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ortoma AB |
Gothenburg |
|
SE |
|
|
Family ID: |
60325319 |
Appl. No.: |
16/301439 |
Filed: |
November 14, 2016 |
PCT Filed: |
November 14, 2016 |
PCT NO: |
PCT/SE2016/051118 |
371 Date: |
November 13, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 2034/2048 20160201;
A61B 2034/104 20160201; A61B 2034/2072 20160201; A61B 90/08
20160201; A61B 2034/2051 20160201; A61B 34/10 20160201; A61B
2560/0223 20130101; A61B 17/1659 20130101; A61B 2034/105 20160201;
A61B 34/20 20160201; A61B 2034/107 20160201; A61B 90/98 20160201;
A61B 2017/00477 20130101; A61B 2090/0811 20160201; A61B 34/25
20160201; A61B 90/37 20160201; A61B 2017/00725 20130101; A61B
2034/2055 20160201; A61B 2090/3983 20160201; G16H 40/63
20180101 |
International
Class: |
A61B 34/20 20060101
A61B034/20; A61B 34/10 20060101 A61B034/10; A61B 34/00 20060101
A61B034/00; A61B 90/98 20060101 A61B090/98; A61B 90/00 20060101
A61B090/00; A61B 17/16 20060101 A61B017/16; G16H 40/63 20060101
G16H040/63 |
Foreign Application Data
Date |
Code |
Application Number |
May 15, 2016 |
SE |
1650650-3 |
Claims
1. An attachment component for attaching a tracker of a navigation
system to an instrument, said attachment component comprising: a
body, an instrument interface attached to the body and configured
for detachable attachment of the attachment component to an
instrument or implant; a tracker interface attached to the body and
having a fixed pre-defined shape for engagement with a calibrated
tracker interface of the tracker, wherein the instrument interface
has in an arbitrary un-calibrated position relative the tracker
interface.
2. The attachment component according to claim 1, wherein at least
the body and the instrument interface are formed as an integral
unit, and wherein the instrument interface comprises at least one
recess for engagement with the surgical instrument, or the
instrument interface comprises at least one clamp for clamping the
attachment component to surgical instrument.
3. The attachment component of claim 1, wherein at least one of
position and orientation of the tracker interface relative the
position and orientation of the instrument interface is
adjustable.
4. The attachment component according to claim 1, wherein the fixed
predefined shape of the tracker interface comprises an
anti-rotational feature, which is non-circular and non-spherical,
for anti-rotational engagement to a surface of the tracker
interface of the tracker having a complementary shape.
5. The attachment component according to claim 1, wherein the
tracker interface comprises a locking feature, for locking
engagement of the tracker interface to a tracked surface of the
tracker.
6. A set of attachment components, comprising at least two
attachment components according to claim 1, wherein the instrument
interface of at least two of said attachment components have
different geometrical shapes, and wherein the tracker interface of
at least two of said attachment components have identical
geometrical shapes.
7. The set of attachment components according to claim 6, wherein
each attachment component further comprises an electronically
readable identifier configured to identify at least one of
instrument brand and instrument type of the surgical instrument,
for which the instrument interface of the attachment component is
configured.
8. The set of attachment components according to claim 7, wherein
said electronically readable identifier comprises a transmitter for
wirelessly transmitting an identification code unique for said at
least one of instrument brand and instrument type of the surgical
instrument, for which the instrument interface of the attachment
component is configured.
9. A device, comprising, in combination, an attachment component
according to claim 1 and a calibration station having a tracker
interface identical to the tracker interface of the attachment
component, wherein the calibration station is associated with a
known calibration location for an end effector of an instrument,
wherein the tracker interface of the calibration station has a
fixed position relative the calibration location.
10. The device according to claim 9, further comprising, in
combination, an instrument, and at least two trackers of a
navigation system, wherein each tracker comprises a tracker
interface with a trackable surface having a pre-defined shape and
location, wherein the instrument interface of the attachment
component is attachable to the instrument, a first tracker is
attachable to the tracker interface of the attachment component,
and a second tracker is attachable to the tracker interface of the
calibration station.
11. A navigation system comprising; at least one tracker attachable
to an instrument to be tracked; a localizer for tracking at least
one of position and orientation of said at least one tracker;
wherein the at least one tracker comprises a position transmitter
and a tracker interface for attaching the at least one tracker to
said instrument; and the navigation system is arranged to report
position and orientation of the tracker interface of the
tracker.
12. The navigation system according to claim 11, wherein the
navigation system is a surgical navigation system and the
instrument is a surgical instrument.
13. A method for tracking position and orientation of an instrument
using a navigation system including a plurality of trackers and a
localizer for identifying the position and orientation of the
tracker, comprising receiving identity data from at least one
tracker of the navigation system, said tracker identity data being
unique for each tracker in the navigation system; receiving
position and orientation data of a tracker interface being attached
to a tracker interface of an attachment component; obtaining
calibration data defining the position and orientation of a portion
of the instrument relative a tracker interface of the attachment
component; and translating the position and orientation data of the
tracker interface into position and orientation data of the
instrument using said identity data and said calibration data.
14. A computer program product stored on a computer usable medium,
comprising: computer readable program means for causing a computer
to carry out the method of claim 13 when executed.
Description
FIELD OF THE INVENTION
[0001] This invention pertains in general to the field of
navigation systems for tracking objects in an area of interest,
such as instruments. More particularly, the invention can be
implemented into a surgical navigation system for tracking position
and orientation of surgical instruments, including implants,
relative position and orientation of patient anatomy during
surgery. The position and orientation data of the instrument may be
presented in real-time in relation to a pre-operative plan
including a virtual representation of the patient anatomy. The
navigation system comprises a plurality of trackers. A tracker is
attached to the instrument using an uncalibrated attachment
component with an arbitrary shape unknown to the navigation system.
Each of the tracker and the attachment component comprises a
tracker interface. The position and orientation of the tracker
interface of the tracker relative a position and orientation of a
transmitter of the tracker is predetermined and known to the
navigation system. The navigation system reports the position and
orientation of the tracker interface of the tracker. According to a
method, position and orientation of the instrument is tracked by
tracking the position and orientation of the tracker interface of
the attachment component.
BACKGROUND OF THE INVENTION
[0002] Orthopedic replacement systems, such as hip, knee, foot and
ankle, shoulder, elbow, and spine replacement systems are commonly
available. These systems comprise implants including various
components for total replacements of a piece of the patient's
anatomy. Each system comprises a range of components, including
various sizes. For example, a hip replacement system can comprise
an acetabular component, which includes an acetabular shell, and
acetabular insert, and a bearing, and the femoral component, which
includes the femoral stem. The systems can be cemented or
press-fit. Furthermore, a wide variety of system specific
instruments are used with each replacement system. Again taking a
hip replacement system as an example, such as system may include
instruments including osteotomes, reamers, saws, handles, planars,
reamers, stem inserters, stem impactors, head impactors, chisels,
broach handles, and trial components. Many times, the instruments
are combined in kits, which include the required instrumentation
for a particular replacement system. The instruments are to a large
extent for multiple use.
[0003] Different replacement systems may be available on different
markets. On each market, a number of competitive replacement
systems are often available. On top of this, different replacement
systems are available for the various surgical fields exemplified
above. In summary, that means that there are a large number of
replacement systems, and an even larger number of implant
components and instruments, available on the global market.
Providing a generic navigation system that is applicable to all of
these replacement systems is challenging.
[0004] Surgeons generally select to work with a few replacement
systems for a particular surgical intervention, such that a
replacement surgery suitable to the individual patient can be
provided. This means that the surgeon can have the required
instruments available, and have a limited number of implant
components in stock to be able to select amongst a few suitable
implant components during surgery. Since the surgeon only works
with a limited number of replacement systems, the surgeon can
master these replacement systems in order to perform a surgery at
the best of his/her ability. Yet, there are a large number of
surgical interventions where the implant components are positioned
in non-optimal positions, with non-optimal surgical outcome for the
patient. Hence, there is a need for improvement of the positioning
of implant components for orthopedic replacement systems. However,
the surgeon do not want to work with different surgical navigation
systems that are each specific for a single replacement system.
Instead, the flexibility to select the most appropriate navigation
system is desired and at the same time use the replacement system
with which the surgeon is familiar.
[0005] Various Computer Assisted Orthopedic Systems (CAOS) exist,
which range from active robotic to passive or navigation systems.
Active robotic systems are capable of performing surgery
autonomously without interaction by the surgeon. Semi-automatic
robotic systems also exist, which give the surgeon more freedom,
but still within certain limitations. Many times, the surgeon wants
to be in control of the surgery. In such situations, passive or
semi-automatic navigation systems are preferred, which provide
additional information during a procedure compared to conventional
surgery but do not perform the surgical action. The surgeon
controls the intervention but acts on additional patient
information obtained from a pre-operative scan. During surgery with
a robotic system, the surgical instrument is not in the hands of
the surgeon but carried by a robot, which is only indirectly
controlled by the surgeon.
[0006] Common to the robotic and surgical navigation systems is
that they use some type of passive or active marker, which a
receiver or locator can follow in real time. Many of these systems
use a number of passive geometrical objects, such as spheres,
arranged in a particular patter from which the instruments'
position and orientation in space can be tracked. These geometrical
objects have a predefined fixed relationship relative the position
and orientation of the end effector of the surgical instrument.
Therefore, also common to these robotic and surgical navigation
systems is that system specific surgical instruments are required
for each navigation system to accurately and reproducibly align
implant components with the pre-operative plan. That means, in
order for a surgeon who wants to use a navigated replacement system
in order to improve the accuracy of replacement component
positioning, but who currently uses a particular replacement system
that is not designed for surgical navigation, the surgeon has to
switch to a new unfamiliar replacement system, including new an
unfamiliar instruments. Furthermore, if the surgeon currently is
using multiple replacement systems that are not navigated, the
surgeon may be limited to choose a single navigated surgical
replacement system, since it is not economically viable to have
multiple navigated replacement systems, it is simply too expensive.
The navigated replacement system may provide a better surgical
outcome, but still not be optimal. Even an experienced surgeon will
be, at least initially, inexperienced with a new surgical
navigation system. Therefore, there exists a need for a surgical
navigation system that can be used with any orthopedic replacement
system, also non-navigated replacement systems, already available
on the marked and with which the surgeon is already familiar, such
that the surgeon does not need any training on the replacement
system, with which he/she is already experienced.
[0007] WO2011134083 discloses systems and methods for surgical
guidance and image registration, in which three-dimensional image
data associated with an object or patient, is registered to
topological image data obtained using a surface topology imaging
device. The surface topology imaging device may include fiducial
markers, which may be tracked by an optical position measurement
system that also tracks fiducial markers on a movable system
specific instrument. The system specific instrument may be
registered to the topological image data, such that the topological
image data and the movable system specific instrument are
registered to the three-dimensional image data. The system may also
co-register images pertaining to a surgical plan with the
three-dimensional image data. The fiducial markers may be tracked
according to surface texture. The system utilizes fiducial markers
attached to system specific surgical instruments that have a fixed
relationship relative to an end-effector of the instrument. Hence,
the system becomes complicated and expensive, since system specific
surgical instruments with fiducial markers are required. The
position of the end-effector of the surgical instrument is
determined and recorded using a 3D model of the surgical
instrument, which is imported from computer aided design (CAD)
drawings, in which the instrument tip is known. Alternatively, the
surgical instrument including the fiducial markers can be profiled
with a structured light scanner to obtain its 3D geometry. The
instrument tip and orientation axis are determined from an acquired
point cloud. These are time-consuming processes for obtaining the
positions of the instrument tip relative the fiducial markers,
which is undesired during surgical action where time is a scarce
resource, not only during the surgical action itself but also in
preparation therefore.
[0008] US2009234217A1, US2011251607, and US2007238981A1 disclose
various aspects of navigation systems. However, utilizing various
types of fiducial markers, they all suffer from at least the same
issues as the navigation system disclosed in WO2011134083, such as
in relation to the calibration of the position of the end-effector
or tool-tip relative fiducial markers.
[0009] U.S. Pat. No. 5,921,992 discloses intraoperative calibration
of an arbitrary surgical instrument relative a surgical navigation
digitizing system. The system comprises a calibration guide that
has markers in known positions relative a guide tube. Hence, the
entire calibration guide is pre-calibrated relative a camera system
and its position is known in the navigation system. Alternatively,
a calibrated guide has a chuck that can be closed on a probe end of
an instrument. The instrument is an existing calibrated instrument
so that its probe end and tip position are already known in the
coordinate system of the cameras. Inserting the pre-calibrated
instrument will determine the position of the calibration guide.
Then, the pre-calibrated instrument is removed from the chuck, and
the position of other instruments having the same shape as the
pre-calibrated instrument can be calibrated into the coordinate
system of the cameras by inserting its probe into the chuck. An
array of light markers can be directly clamped to the instrument
before calibration. This system is very inflexible, since it may
only be used together with instruments having identical shapes and
positions of the probe end. Also, if the calibration instrument is
moved, it has to be re-calibrated. Adding a new instrument, or
using the system together with a different replacement system,
requires multiple calibration guides and/or new calibration
probes.
[0010] U.S. Pat. No. 7,166,114 discloses a surgical navigation
system that does not require a calibration system to track the axis
of an instrument. Instead, a tracker is attached to the instrument
using a pre-calibrated adapter. The adapter has a known relation
between the coordinate system of the tracker and the surgical tool
or tool axis. This is done by having precise knowledge of location
of the adapter relative the tool axis when the adapter is attached
to the surgical tool. This requires pre-characterisation of each
adapter of the system to each surgical tool with which it is used.
Utilizing the tracker for different replacement systems, or even
surgical tools with different geometrical shapes, requires a
database where the location of the surgical tool axis relative the
adapter and tracker coordinate system is stored. The adapter and
tracker have to be characterised in the same coordinate system.
Adopting the navigation system to new replacement systems or
surgical instruments is complex, expensive and time-consuming and
requires precise characterization of each adapter.
[0011] US2005/0288575 recognizes that adapters such as described in
U.S. Pat. No. 7,166,114 are expensive and time-consuming to
develop. The solution is to have an adapter that is coupled to a
surgical tool in a non-fixed manner, and can be calibrated by
moving the adapter along the tool axis. It is only possible to
track the tool axis, but not the end-effector of the tool. Also, it
is only possible to track position, not orientation. Similar to
other adapter based systems, the navigation system knows the
identity of the particular adapter and the surgical instrument. The
system is queried with regard to the dimensions of the interface
and channel configuration of the adapter, and the dimensions of the
surgical tool and its effector axis. Hence, the adapter needs to be
pre-calibrated, i.e. its shape between an interface for attaching
the tracker to the adapter and an interface for coupling the
adapter in a non-fixed manner to the surgical tool is known and
stored in a database. Again, this system requires
pre-characterisation of each adapter of the system to each surgical
tool with which it is used, with the same challenges as with regard
to the system of U.S. Pat. No. 7,166,114.
[0012] Hence, an improved surgical navigation method and system and
associated attachments would be advantageous, and in particular
allowing for improved guidance, precision, increased flexibility,
cost-effectiveness, calibration and/or patient safety for use
together with any orthopedic replacement system and surgical
instruments of arbitrary shape available on the market would be
advantageous.
SUMMARY OF THE INVENTION
[0013] Accordingly, embodiments of the present invention preferably
seek to mitigate, alleviate or eliminate one or more deficiencies,
disadvantages or issues in the art, such as the above-identified,
singly or in any combination by providing the method and system
according to the appended patent claims.
[0014] Embodiments comprises an attachment component for attaching
a tracker of a navigation system to an instrument that comprises a
body, an instrument interface attached to the body and configured
for detachable attachment of the attachment component to an
instrument or implant, a tracker interface attached to the body and
having a fixed pre-defined shape for engagement with a calibrated
tracker interface of the tracker. The instrument interface has in
an arbitrary un-calibrated position relative the tracker
interface.
[0015] At least the body and the instrument interface may be formed
as an integral unit. The instrument interface may comprise at least
one recess for engagement with the surgical instrument.
Alternatively or additionally, the instrument interface comprises
at least one clamp for clamping the attachment component to
surgical instrument.
[0016] At least one of position and orientation of the tracker
interface may be adjustable relative the position and orientation
of the instrument interface.
[0017] The fixed predefined shape of the tracker interface may
comprise an anti-rotational feature, which is non-circular and
non-spherical, for anti-rotational engagement to a surface of the
tracker interface of the tracker having a complementary shape. The
tracker interface may comprise a locking feature, for locking
engagement of the tracker interface to a tracked surface of the
tracker.
[0018] Embodiments disclosed herein comprise a set of attachment
components. The set may comprise at least two attachment components
according to the embodiments of the attachment components disclose
herein. The instrument interface of at least two of the attachment
components may have different geometrical shapes. The tracker
interface of at least two of said attachment components have
identical geometrical shapes. Each attachment component of the set
may further comprise an electronically readable identifier
configured to identify at least one of instrument brand and
instrument type of the surgical instrument, for which the
instrument interface of the attachment component is configured. The
electronically readable identifier may comprise a transmitter for
wirelessly transmitting an identification code unique for said at
least one of instrument brand and instrument type of the surgical
instrument, for which the instrument interface of the attachment
component is configured.
[0019] Embodiments disclosed herein also comprise a combination of
an attachment component according the disclosed embodiments and a
calibration station having a tracker interface identical to the
tracker interface of the attachment component. The calibration
station may be associated with a known calibration location for an
end effector of an instrument. The tracker interface of the
calibration station has a fixed position relative the calibration
location. A tracker is attachable to the tracker interface of the
calibration station. The combination may also comprise an
instrument, and at least two trackers of a navigation system. Each
tracker may comprise a tracker interface with a trackable surface
having a pre-defined shape and location. The instrument interface
of the attachment component may be attachable to the instrument, a
first tracker may be attachable to the tracker interface of the
attachment component, and a second tracker may be attachable to the
tracker interface of the calibration station.
[0020] Embodiments disclosed herein comprises a navigation system
comprising at least one tracker attachable to an instrument to be
tracked, a localizer for tracking at least one of position and
orientation of the at least one tracker; and at least one tracker
that comprises a position transmitter and a tracker interface for
attaching the at least one tracker to the instrument. The
navigation system is arranged to report position and orientation of
the tracker interface of at least one of the trackers. The
navigation system may be a surgical navigation system and the
instrument may be a surgical instrument.
[0021] Embodiments disclosed herein comprise a method for tracking
position and orientation of an instrument using a navigation system
including a plurality of trackers and a localizer for identifying
the position and orientation of the tracker. The method comprises
receiving identity data from at least one tracker of the navigation
system, said tracker identity data being unique for each tracker in
the navigation system; receiving position and orientation data of a
tracker interface being attached to a tracker interface of an
attachment component; obtaining calibration data defining the
position and orientation of a portion of the instrument relative a
tracker interface of the attachment component; and translating the
position and orientation data of the tracker interface into
position and orientation data of the instrument using said identity
data and said calibration data.
[0022] Embodiments disclosed herein comprise a computer program
product stored on a computer usable medium, comprising computer
readable program means for causing a computer to carry out the
embodiment of the methods disclosed herein when executed.
[0023] The embodiments of attachment components, calibrations
stations and methods, and methods for associating a pre-operative
plan with tracking data discloses a system that is flexible and may
be adapted to any orthopedic replacement system already existing on
the market. The system is particularly useful for replacement
systems where multiple differently shaped instruments are used
during the course of the intervention. Furthermore, solutions
described herein provides for configuring the system such that the
system may be installed in different environments with maintained
accuracy and without affecting the way the surgeon is used to work
with the instruments he/she is familiar with. The shape of the
instruments do need to be known to the system. Hence, the
attachment components and trackers do not need to be characterized
in the system, which becomes less complex than previous systems.
The embodiments do not impair the capabilities of the existing
instruments; rather the operator gets access to real time data as
well as data from a pre-operative plan that enhances the use of the
instruments for a better outcome of the procedure. Furthermore, the
system can be adapted to any tool of any orthopedic replacement
system, even without prior knowledge of its shape. This means that
the same system may be used by different surgeons for different
interventions, only by exchanging attachment components. Different
surgeons for the same intervention can adapt positions and
orientations of the components to his/her desire without impairing
tracking of the instruments. Even the position tracker can be
positioned in an optimal position, and the position and orientation
of the tracker attached to the instrument be adapted to an optimal
position and orientation relative the position tracker within the
specific environment within which the system is deployed. This
means that the system can be used with any replacement system in
virtually any environment with maintained accuracy while the
operator uses the tools and instruments he/she is familiar
with.
[0024] Further embodiments of the invention are defined in the
dependent claims.
[0025] It should be emphasized that the term "comprises/comprising"
when used in this specification is taken to specify the presence of
stated features, integers, steps or components but does not
preclude the presence or addition of one or more other features,
integers, steps, components or groups thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] These and other aspects, features and advantages of which
embodiments of the invention are capable of will be apparent and
elucidated from the following description of embodiments of the
present invention, reference being made to the accompanying
drawings, in which
[0027] FIGS. 1a-1c are schematic views of a surgical navigation
system;
[0028] FIGS. 2a-2e are perspective views of attachment components
having a tracker interface and an instrument interface;
[0029] FIG. 3 is a perspective view of a tracker interface of the
tracker and a tracker interface of the attachment component;
[0030] FIG. 4 is a block diagram of a surgical navigation system
including a navigation system;
[0031] FIGS. 5a-5e are schematic views of a method and a system for
associating position and orientation of a surgical instrument
relative a pre-operative plan;
[0032] FIGS. 6a-6d are schematic views of a calibration process for
calibrating the position and orientation of an instrument within a
navigation system;
[0033] FIG. 7 is a side view of a tracker attachable to an
attachment component;
[0034] FIGS. 8a-8c are side and perspective views, respectively, of
a tracker interface of an attachment component;
[0035] FIGS. 9a-9c are side and perspective views, respectively, of
a tracker interface of a tracker in non-aligned, non-locked, and
locked positions, respectively, relative a tracker interface of an
attachment component;
[0036] FIGS. 10a-10d are side-views of embodiments of calibration
objects attached to surgical instruments; and
[0037] FIGS. 11a-11b are perspective views of embodiments of
calibration objects.
DESCRIPTION OF EMBODIMENTS
[0038] Specific embodiments of the invention will now be described
with reference to the accompanying drawings. This invention may,
however, be embodied in many different forms and should not be
construed as limited to the embodiments set forth herein; rather,
these embodiments are provided so that this disclosure will be
thorough and complete, and will fully convey the scope of the
invention to those skilled in the art. The terminology used in the
detailed description of the embodiments illustrated in the
accompanying drawings is not intended to be limiting of the
invention. In the drawings, like numbers refer to like
elements.
[0039] The following description focuses on embodiments of the
present invention applicable to a surgical navigation system.
However, it will be appreciated that the invention is not limited
to this application but may be applied to many other procedures,
such as other navigation systems where the position and/or
orientation of an object is tracked. The examples given in the
below embodiments relate to a hip replacement surgery and spine
surgery. Other embodiments include knee surgery, spine surgery,
elbow surgery, ankle surgery, and other replacement surgeries.
[0040] In the below embodiments, reference is made to tracking
position and orientation of instruments. In this context, the term
instruments, in addition to instruments for the surgical examples
given herein, include implant components, such as for replacement
of patient anatomy or adding into the patient anatomy, as well as
for temporary attachment of components of the replacement system
during the surgical intervention. Such temporary components may
include threaded screws or unthreaded nails for temporary attaching
trackers to the patient anatomy during surgery in the same way as
the trackers are attached to the attachment components, as will be
described herein. Furthermore, instruments include surgical guides
that may attached to the anatomy or implants for guiding the
instrument or checking accuracy of an installed implant, such as
checking rotation, position, and/or orientation of an implant.
[0041] FIGS. 1a-1c illustrate embodiments of a surgical navigation
system. Parts of this system have been disclosed in patent
application no. PCT/SE2013/050952 by the same applicant as the
applicant of the present invention, which is incorporated herein in
its entirety for all purposes. The surgical navigation system of
patent application no. PCT/SE2013/050952 has been further improved
by embodiments of the present invention.
[0042] The surgical navigation system comprises a calibration unit
1. Furthermore, the navigation system comprises at least two
trackers 2a, 2b, 2c, 2d, 2e. In the present example, five trackers
2a-2e are illustrated. However, a particular tracker may be moved
between various instruments 3a, 3b depending on the particular
work-flow of the surgery at which the system is used. The complete
system may be used with only two trackers 2a-2e. A particular
tracker 2c, 2d may also be attached to an implant, e.g. a temporary
screw or nail, which in turn is attached to patient anatomy for
tracking position and orientation of the patient anatomy during
surgery. A tracker may also be attached to an implant to guide
positioning of the implant and/or check positing and orientation of
the implant after it has been seated. The calibration unit 1 may be
adapted to calibrate at least one of position and orientation of
any tracker 2a-2e associated with an instrument or implant within
the surgical navigation system. Calibrating the tracker position
and/or orientation allows for calibrating the position and
orientation of the surgical instrument 3a, 3b, such as an
end-effector and/or axis thereof. The surgical navigation system is
provided within the surgical theatre or operating room.
[0043] FIG. 1b illustrates an instrument 3a in the form or a probe,
which may be used to locate the position of various structures,
e.g. patient anatomy, landmarks, etc. which have a correspondence
in a preoperative plan such that the structure can be registered to
a corresponding virtual structure in a preoperative plan. Such a
virtual structure may comprise a surface representation of patient
anatomy obtained from CT data.
[0044] FIG. 1c illustrates tracking the position and/or orientation
of a surgical instrument 3b. The surgical navigation system also
comprises a feedback unit, such as a display 4. The patient
structure may be aligned with the virtual structure during a
registration process. Utilizing the components of the surgical
navigation system, the position and orientation of the surgical
instrument 3b relative to the pre-operative plan and the patient
structure may be tracked in real-time, such as illustrated in FIG.
1c, wherein the position and orientation of a virtual
representation of the surgical instrument is displayed in relation
to the virtual structure in the preoperative plan in the same
relationship as the surgical instrument 3b to the patient structure
in real-time. A straight line representing the axis of the surgical
instrument 3a may be shown as the virtual representation on the
display 4 relative the virtual object. The pre-operative plan may
be provided from a software module for planning a surgical
intervention based on CT or other 3D patient specific data
including data of the anatomy subject of the surgery. The virtual
representation of the surgical structure shown on the display 4 may
be surface models segmented based on the patient specific data. The
display 4 and surgical navigation system may be connected to and
implemented by a computer 5 for processing data from the navigation
system. The computer 5 may render the pre-operative plan and the
position and orientation of tracked instruments 3a-3b relative the
pre-operative plan. A position tracker 6 or localizer, such as an
array of cameras or receiver of radio based position data, is
configured to track current position and/or orientation of the
trackers 2a-2e in its area of coverage.
[0045] According to embodiments, the tracker 2a-2e comprises a
tracker interface, i.e. an attachment interface, for attaching the
tracker to another object in a fixed position. The coordinate
system of each tracker 2a-2e is defined relative the tracker
interface. Other objects or structures of the tracker are
calibrated or characterized against the tracker interface. This
means that the tracker can track an object, such as an instrument,
of arbitrary shape and be attached at an arbitrary position
relative to the object. For example, the tracker interface may
comprise a chuck. In the embodiments of a surgical navigation
system, this means that the tracker can be attached to any surgical
instrument at any position thereof, to which the chuck can be
attached. This, in turn, means that the navigation system can be
easily adapted to track components of any replacement system, such
as surgical instruments and implants. Hence, the surgical
navigation system is very flexible.
[0046] In order to make the system even easier to implement, and/or
configure to a replacement system that has not been previously
supported, embodiments of the present invention comprises an
attachment component. The attachment component provides a precise
tracker interface on an instrument that does not have such a
tracker interface when it was made. Hence, replacement systems
already available can be retrofitted with a navigation system. The
attachment component can be produced by rapid productions
techniques, such as 3D printing. It may be designed such that it
fits to the instrument in a position where it may be fixed, and the
attachment component and instrument form a rigid body, at least
temporarily.
[0047] FIGS. 2a-2e illustrate various attachment components 10a-10d
for attachment of a tracker 2a-2e to different objects, such as
surgical instruments 14a-14c or implants. In the following,
reference is made to an instrument as an example of an object, but
may equally be an implant or other object of a replacement
system.
[0048] The attachment component 10a-10d is provided for attaching
the tracker to the instrument such that the tracker 2a-2e, the
attachment component 10a-10d, and the instrument 3a-3b forms a
rigid body in use. The attachment component 10a-10d may be
retrofitted into a fixed non-moveable position relative the
instrument such that the position and orientation of the instrument
may be tracked by tracking the position and orientation of the
tracker 2a-2e. The position and orientation of the tracker relative
the instrument is arbitrary and does not need to be known.
[0049] Each attachment component 10a-10d comprises a body 11a-11d,
an instrument interface 12a-12d, and a tracker interface 13a-13d.
The instrument interface 12a-12d is attached to the body 13a-13d.
Also, it may be configured for detachable attachment of the
attachment component to the surgical instrument 3a-3b, such as at a
predefined position and orientation. Hence, the tracker is not
moveable relative the instrument 3a-3b while it is tracking the
instrument 3a-3b. However, it may be removed at other times, such
as during sterilization of the instrument 3a-3b. The attachment
component may be delivered as a pre-sterilized consumable or be a
sterilizable multiple-use component.
[0050] Furthermore, the tracker interface 13a-13d may be attached
to, such as formed integral with or be connectable to, the body
13a-12c. The tracker interface 13a-13d may have a fixed pre-defined
shape for engagement with a tracker interface of the tracker, which
may be calibrated. This means that the attachment component
10a-10d, and any object attached in an arbitrary position and
orientation thereto are defined relative the tracker interface
13a-13d of the attachment component 10a-10d. Furthermore, the
instrument interface 12a-12d has an arbitrary un-calibrated
position relative the tracker interface 13a-13d. Hence, the
navigation system does not know the position and orientation of the
instrument interface 12a-12d relative the tracker interface
13a-13d. This is possible since the coordinate system of the
tracker 2a-2e is provided at a location that may be shared by the
tracker interface of the tracker 2a-2e and the tracker interface
13a-13d of the attachment component 10a-10d. The body 11a-11d, the
instrument interface 12a-12d, and the tracker interface 13a-13d of
the attachment component 10a-10d may form a rigid body in use.
Hence, the tracker 2a-2e, the attachment component 10a-10d, and the
instrument 3a-3b form a rigid body unit in use when the tracker
2a-2e is attached to the tracker interface 13a-13d of the
attachment component 10a-10d and the instrument 3a-3b is attached
to the instrument interface 12a-12d to provide a fixed relationship
between the tracker interface of the tracker 2a-2e and the surgical
instrument 3a-3b.
[0051] In some embodiments, the instrument interface 13a-13d is
arranged at an arbitrary un-calibrated position and orientation
relative the tracker interface 13a-13d. This arbitrary
un-calibrated position and orientation may be adjustable, such as
to different fixed relative positions and/or orientations. In order
for the tracker interface 13a-13d to form a rigid body with the
body 11a-11d and the instrument interface 12a-12d, the adjustable
arbitrary un-calibrated position and orientation may be locked at
different positions and orientations such that the tracker
interface 13a-13d has a fixed position and orientation relative the
body 11a-11d in use. This provides for arranging the tracker 2a-2e
in an optimal position and orientation relative the position
tracker 6 independent of the position and orientation of the
position tracker 6. For example, the layout or the operating room
and other surgical equipment may impose restrictions on the
position and orientation of the position tracker 6. It may need to
be positioned differently relative the patient in different
operating rooms, or even in the same operating room depending on
the circumstances, type of surgical procedure etc. That means that
the line of sight between the position tracker 6 and the tracker
2a-2e when the surgeon uses the instrument may be sufficient at one
position of the position tracker 6, but blocked from another
positions of the position tracker 6 if the relative position of the
tracker interface 13a-13d is fixed and not adjustable. On the other
hand, when the tracker interface 13a-13d is adjustable relative the
instrument interface 12a-12d, the position and orientation of the
tracker 2a-2e, when attached to the instrument 3a-3b, relative the
position tracker 6 can be adjusted to an optimal position for a
clear line of sight while instrument can be used as desired. The
same applies if different surgeons orient the same instrument
differently during use. The tracker 2a-2e can be arranged at an
optimal position for a clear line of sight for each surgeon. Hence,
the system is more flexible. Once the position of the tracker
interface 13a-13d relative the instrument interface 12a-12d has
been adjusted and locked, calibration may commence as is described
below.
[0052] At least the body 11a-11d and the instrument interface
12a-12d of the attachment component 10a-10d may be formed as an
integral unit. Hence, precision and accuracy is provided for.
Furthermore, the instrument interface 12a-12b may comprise at least
one recess 20b-20d for engagement with the surgical instrument,
such as is illustrated in FIGS. 2b, 2d and 2e. The instrument
interface 12a-12d may have a shape that is specific for each
instrument, such as a shape that is complementary to the shape of
an exterior surface of the instrument. This enables a stable and
fixed attachment of the attachment component 11a-11d. However, the
position and orientation of the tracker interface 13a-13d of the
attachment component 11a-11d may still be unrelated to the position
and orientation, and thus shape, of the instrument. This also
provides for precision and reliability, such that the components
may not be disengaged by mistake and such that the coordinate
system of the tracker 2a-2e is shared at the respective tracker
interfaces 13a-13d.
[0053] Alternatively or additionally, the instrument interface
12a-12d of the attachment component 10a-10d may comprise at least
one clamp for clamping the attachment component 10a-10d to the
instrument 3a-3b. In the embodiment of FIG. 2b, the instrument
interface 12b is annular with a recess in the axial direction of
the instrument and though the body in order to provide sufficient
flexibility to the body 11b such that a snap fit connection is
provided. The snap-fit instrument interface may have a ridge or rim
that engages an annular recess of the surgical instrument 14b. In
the embodiment of FIG. 2d, the recess 20c provides an opening for
inserting a shaft of the surgical instrument 14c, such as a spine
punch tool. Also illustrated with regard to this embodiment is a
handle of the surgical instrument received in the instrument
interface 12c. The handle is in this embodiment spherical whereas
the instrument interface is part spherical. Hence, the shape of the
instrument interface 12c may at least partly conform to a shape of
a handle of the instrument 14c. Other shapes of the handle are
conceivable.
[0054] As is illustrated in the embodiment of FIG. 2a, the
attachment component may comprise a recess 15 that extends around,
or partially around, the body 11a. The recess may be sized and
configured to receive a tie or band, such as a rubber band or cable
tie, that wraps around the body 11a and a portion of the
instrument, such as a handle thereof. The tie or band and
instrument interface forms a clamp for clamping the attachment
component 10a to the instrument 14a.
[0055] FIG. 2e illustrates an embodiment wherein at least one of
position and orientation of the tracker interface 13d is adjustable
relative the position and orientation of the instrument interface.
To the left in FIG. 2e, the tracker interface 13d is attached to
the attachment component 10d, and to the right, the tracker
interface 13d is detached from the attachment component 10d. For
example, the tracker interface may be attached to a base, as will
be described below. A stud or protrusion (not shown) may extend
from the base in the longitudinal direction of the tracker
interface 13d, and be received in a recess 21d of the body 11d. In
the illustrated embodiment, the recess 21d and stud are cylindrical
such that the tracker interface 13d may be rotated relative the
longitudinal axis of the instrument interface 12d, whereby its
position and/or orientation is adjusted.
[0056] The body 11d may comprise several recesses for receiving the
stud. Hence, also the position of the tracker interface 13d
relative the instrument interface 12d may be adjusted. The tracker
interface 13 may be fixed in a desired location and orientation
relative the body 11d, such as by applying an adhesive in the
recess 21d. Additionally or alternatively, a press fit connection
between the stud and recess 21d may provide sufficient fixation of
the tracker interface 13d such that it does not move during
operation of the instrument. In this embodiment as well as in the
embodiment of FIGS. 2c-2d, the body 11c-11d comprises a surface 22d
that is non perpendicular relative the instrument interface
12-c-12d. Hence, the longitudinal axis of the tracker interface
13c-13d will be non-parallel to the longitudinal axis of the
instrument, and improved line of sight may be obtained.
Furthermore, the body 11c-11d may comprise multiple such
non-perpendicular surfaces 22c-22d at which the tracker interface
13c-13d may be attached to the body 11c-11d to accommodate for
different situations, wherein each surface 22c-22d may comprise at
least one recess 21d for receiving the stud.
[0057] Furthermore, in some embodiments, the base of the tracker
interface comprises a lockable swivel joint, by means of which the
tracker interface 13a-13d may be rotated and/or tilted relative the
instrument interface 12a-12d. Such a swivel joint may be provided
by a ball received in a seat or socket, and the ball locked to the
socket by a screw or nut pressing the ball towards the socket to a
locked position. The swivel joint provides for an adjustable
position and/or orientation of the tracker interface 13a-13d.
[0058] As is illustrated in FIG. 2e, the body 11d may have a recess
20d extending in the longitudinal direction of the instrument
interface 12d whereby two arms are formed by the body that extends
transverse to the instrument interface. The instrument may be
received into the instrument interface 12d through the recess 20.
The instrument interface 20d may be clamped to the instrument by
tightening the arms around the instrument. The arms may be
tightened by a snap fit connection, or by a bolt (not shown)
received in a recess 23d transverse to the arm. The head of the
bolt may be received in one of the arms, and a nut or threads
provided in the other arm. Closing the arms will clamp the
attachment component 10d to the instrument.
[0059] The attachment component may be made by a sterilizable
material, such as medical grade plastics or metal. Components made
of medical grade material are particularly suitable for rapid
prototyping, such that attachment components easily can be
manufactured and navigation of additional instruments made possible
without any adaptation of other components of the navigation system
or databases in the system.
[0060] FIG. 3 illustrates an embodiment of the tracker interface 24
of the attachment component and the tracker interface 25 of the
tracker (the attachment component and tracker are not illustrated
in FIG. 3). A fixed predefined shape of the tracker interface
comprises an anti-rotational feature, which may be non-circular and
non-spherical. This provides f anti-rotational engagement of a
surface of the tracker interface 25 of the tracker to a surface of
the tracker interface 24 of the attachment component having a
complementary shape. In this embodiment, the anti-rotational
feature of the tracker interface 24 of the attachment component is
a flat or planar surface of an otherwise cylindrical or conical
surface. The flat surface extends in the longitudinal direction of
the tracker interface 24, 25. Alternatively, the anti-rotational
feature may be a surface that is square, hexagonal, star shaped,
oval, wave shaped or any other non-circular shape in a cross
section taken along the longitudinal axis of the tracker interface
24. The tracker interface 24 of the attachment component may
comprise a protrusion having a base 27, or extending from a base
surface, and a top 28. The base 27 may be wider than the top 28.
Hence, an envelope surface 29, which extends from the base 27 to
the top 28, may be conical, such that the tracker interface 23
forms a truncated cone, which may comprise the flat side surface.
In some embodiments, the envelope surface 29 is circular such that
the tracker may be rotated around the protrusion to a suitable
orientation relative the instrument before it is locked to the
attachment component. This contributes to the flexibility of the
system. A recess or protrusion may be provided in the envelope
surface 29 at least partly around the circumference of the
protrusion, and which may be transverse to the longitudinal axis of
the tracker interface. A locking element of the tracker interface
25 of the tracker may engage the circumferential protrusion or
recess. The locking element may comprise an eccentric member that
engages the circumferential recess, as will be discussed below.
[0061] The tracker interface 25 of the tracker may comprise a boss
30 with a generally flat or planar end surface 31, which may be
part of or form a tip of the tracker, and a recess 32, which is
indicated with phantom lines. The recess 32 may have a shape that
is at least partially complementary to the shape of the envelope
surface 29, such that the tracker interface 25 provides a location
fit, i.e. the tracker interface 24 of the attachment component does
not move relative the tracker interface 25 of the tracker when the
tracker interfaces 24, 25 are completely seated. As is indicated in
FIG. 3, the origin or zero point 33 of the coordinate system of the
tracker may be located at the center of the boss 30 or recess 32.
In the embodiment of FIG. 3, the origin 33 of the coordinate system
of the tracker is located at a plane coinciding with a plane formed
by the flat end surface 31. When the tracker interfaces 24, 25 are
connected, the base 27 will abut the end surface 31. Hence, by
tracking the end surface, components in the system may be related
to this surface in order to provide transformation of the position
and or orientation of other components rigidly attached relative
the tracker.
[0062] The tracker interface 23 of the attachment component
comprises a locking feature, for locking engagement of the tracker
interface to a tracked surface of the tracker, which may be formed
by the end surface 31. The tracker interface 25 of the tracker may
comprise a chuck, as will be discussed below.
[0063] The tracker interface of the attachment component has been
disclosed as having a protrusion and the tracker interface of the
tracker as having a recess for receiving the protrusion. In other
embodiments, the system is reversed such that the tracker interface
of the attachment component comprises the boss and recess and the
tracker interface of the tracker comprises the protrusion and
base.
[0064] Returning to FIGS. 2a-2d, embodiments of the invention
comprises a set of attachment components. The set of attachment
components may comprise at least two attachment components as
described herein. The instrument interfaces of at least two of the
attachment components have different geometrical shapes. Hence,
each instrument interface is configured for a specific instrument
that is used during a particular surgical procedure. However, the
tracker interfaces of at least two of attachment components of the
set have identical geometrical shapes. The set of attachment
components may be configured for instruments and/or implants of a
particular surgical procedure. As such, the set may be provided as
a kit for each surgery, together with or separate from the
implants. A single tracker may be selectively attached to each
attachment component of the set during the procedure. Hence, the
number of trackers in the system may be reduced compared to having
a tracker for each instrument or attachment component.
[0065] Each attachment component may further comprises an
electronically readable identifier configured to identify at least
one of instrument brand and instrument type of the instrument, for
which the instrument interface of the attachment component is
configured. The electronically readable identifier may comprise a
transmitter for wirelessly transmitting an identification code.
Such an electronically readable identifier may include an RFID tag,
a bar code, a QR code, or similar code that is electronically
readable. If the system identifies that the attachment component is
not configured for a particular replacement procedure, the system
may present warnings. For example, a warning may indicate that a
particular replacement component may not be accurately or reliably
attached to the instrument to be used for the surgery. The
instrument to be used may be defined in the system or in a
preoperative plan.
[0066] FIG. 4 illustrates main components of a surgical navigation
system 40. The surgical navigation system may comprise a navigation
system 41, a CAD module 42, the attachment components 10a-10d and a
calibration station 43, which will be further described below. The
CAD module 42 may comprise patient specific volumetric data and
object models based on the volumetric data. The CAD module 42 may
also comprise a pre-operative plan, in which implant component
positions and orientations and/or instrument paths have been
defined relative the patient specific data. The navigation system
41 can be provided as a stand-alone component within the surgical
navigation system 40. This means that the navigation system
provides to the CAD module 42 the position and orientation of each
tracker interface of each tracker 2a-2e in the area of coverage of
the navigation system 41. Furthermore, the navigation system 41 may
provide data of the position and orientation of a tracker interface
of a tracker attached to a calibration station, as will be
discussed below. At calibration, the CAD module 42 may generate a
transformation database or table for each attachment component and
instrument combination, such that the position and orientation of a
tracked surface of the attachment component 10a-10d is known for
determining position and/or orientation of the surgical instrument
3a-3b. The tracked surface of the attachment component 10a-10d may
be the base surface 27 of the tracker interface 24. Hence, the
navigation system 41 only needs to report the position and
orientation of the tracker interface 25 of the tracker, which mates
with the tracked surface of the attachment component 10a-10d. This
means that the surgical navigation system 40 is independent of the
technology of the navigation system 41. The only requirement of a
replacement navigation system 41 is that it reports the position
and orientation of the tracker interface, and potentially tracker
identity data as will be discussed below, and that the replacement
navigation system has a tracker interface that corresponds to the
old tracker interface and fits the tracker interface of the
attachment component. Hence, the surgical navigation system is very
flexible. Furthermore, combinations of attachment components and
instruments can be added to the surgical navigation system at any
time by calibrating the attachment component and instrument
combination, as will be described below. This makes the system very
easy to adapt to new replacement systems and new instruments made
available to already supported replacement systems.
[0067] As is illustrated in FIG. 5a, the tracker 2b may be attached
to the surgical instrument rather than a surgical tool 33, such as
a drilling machine, a planar machine, a sawing machine etc. This
means that the surgeon may use the same machine for different
interventions during the surgical procedure, and may simply
disconnect the surgical instrument and attach a new surgical
instrument without having to calibrate the instrument and
attachment component combination, wherein flexibility of the system
is maintained. A set of attachment components is useful in this
situation. Furthermore, FIG. 5a illustrates a surgical navigation
module that may comprise the CAD module 42 and the display 4, as
will be further described below.
[0068] FIGS. 5b-5e illustrate embodiments of a method and system
for associating the pre-operative plan with position and
orientation of the surgical instrument 3a, 3b, such as by the CAD
module 42. The pre-operative plan may be generated in a planning
module. Such a planning module has been described in
PCT/SE2013/051210, by the same applicant as the applicant of the
present invention and which is incorporated herein by reference in
its entirety for all purposes. The pre-operative plan comprises
patient anatomy data, such as a scan data including the patient
anatomy, for example bony anatomy of the patient. Such scan data
may comprise volume imaging data, such as CT data, MRI data, PET
data, SPECT data etc. The pre-operative plan may also comprise
planned position and orientation of an implant and/or surgical
instrument relative the patient anatomy data. The pre-operative
plan may also comprise trajectories of the surgical instrument for
a planned outcome, such as the trajectory of a cut or drilling
action. Furthermore, the pre-operative plan data may comprise
surface models, such as STL models, generated based on the patient
anatomy data. The pre-operative plan may also comprise a
combination of the indicated data types. Hence, the pre-operative
plan comprises large sets of data that the surgeon may benefit from
during the surgical procedure but which he/she has previously not
had access to during the surgical intervention. The surgeon can
simply not see beyond the surfaces exposed during the surgical
intervention, and cannot imagine any structure hidden by the
exposed surfaces. The present embodiments provide access to patient
data available during a pre-operative planning process, but now
during the surgical intervention without having to manually
interact with the pre-operative plan. The pre-operative plan may be
a pre-operative plan of a hip, a spine, such as spine fusion,
pedicle screw placement, orthopedic joint surgery, an foot and
ankle, shoulder, or elbow surgery.
[0069] The pre-operative plan is not described in further detail
herein. For further details of the pre-operative plan, reference is
made to PCT/SE2013/051210. The pre-operative plan may e.g. be
imported into the CAD module 42. Alternatively or additionally, a
module for preparing the pre-operative plan is provided as a module
within the CAD module 42.
[0070] Initially, the pre-operative plan is not associated with the
position and orientation of the surgical instrument 3a, 3b.
Embodiments herein provide a system and a method, wherein the
pre-operative plan is associated with the position and orientation
of a tracked surgical instrument. According to these embodiments, a
link is provided between the pre-operative plan and the navigation
system while the instrument is used. Hence, the system can
continuously update a virtual representation of the pre-operative
plan while the surgeon moves the surgical instrument. Hence, the
system makes the pre-operative plan useful also during use of the
instruments that are planned for in the pre-operative plan.
[0071] The surgical instrument may comprise a probe to locate a
particular landmark. The surgical instrument may also comprise a
surgical template, such as a template to be attached to an implant
or anatomical structure in order to indicate its position and/or
orientation. Hence, the method may be non-invasive and exercised by
a non-medically trained operator. In the following, reference is
made to a surgeon, but this may equally be a non-medically trained
operator. The embodiments provides a user friendly system, wherein
user interaction with the system is minimized and still the surgeon
can benefit from the data that was used during the pre-operative
plan in real time during surgery. Since this may be combined with
the surgical navigation system presented herein, the surgeon may
operate with conventional tools that he/she is familiar with but
guided by enhanced information that was also used during a
pre-operative planning process.
[0072] The method and system for associating a pre-operative plan
with tracked position and orientation of the instrument will now be
described in relation to FIGS. 5b-5e, which disclose various
embodiments of the method and system.
[0073] A pre-operative plan including patient anatomy data is
provided. In some embodiments, the pre-operative plan includes only
patient anatomy data, such as scan data. An instrument is
associated relative the patient anatomy data only such as relative
bone tissue of the anatomy data. This is useful e.g. in order to
locate various structures of the patient without having to manually
manipulate the patient data on a display. It is difficult to
manually orient the patient data in the system such that it is
oriented relative to an instrument using an input device, such as a
mouse. The instrument in such an embodiment may be a pointer or
probe. In other embodiments, the preoperative plan comprises
planned position and orientation of a surgical object relative the
patient anatomy data. The surgical object may be an implant,
surgical guides, surgical instruments, incision or cutting lines or
planes etc. i.e. an object that is external to the patient anatomy
data and/or external to scan data of the patient.
[0074] The pre-operative plan may be imported into the CAD module
42, such as indicated above. The position and orientation of a
patient anatomy within the navigation system is obtained, such as
by the navigation system, when a tracker is attached to the patient
anatomy. Also, the patient anatomy is referenced to a virtual
representation of the patient anatomy data in the preoperative plan
using the navigation system, such as has been described above. The
patient anatomy and the virtual representation of the patient
anatomy may be dynamically referenced such that position and
orientation of the patient anatomy is continuously tracked and
displayed on the display 4.
[0075] The tracking data contains information of position and
orientation of the instrument 3a, 3b within the navigation system,
such as is described herein, i.e. relative the patient anatomy.
[0076] The method and system for associating the pre-operative plan
with the tracking data comprises a split window 50. The split
window comprises separate parts 51a, 51b, 51c, 51d. Multiple
virtual representations of the surgical instrument 52 are generated
relative multiple virtual representations of the pre-operative plan
depending on the tracking data. Each virtual representation of the
surgical instrument 52 is generated in relation to a virtual
representation of the pre-operative plan in one part of the split
window 50. The multiple virtual representations of the
pre-operative plan are updated based on the position and
orientation of the instrument, i.e. they are dependent on the
tracking data. Different aspects of the pre-operative plan may be
displayed in the separate parts 51a, 51b, 51c, 51d depending on the
position and orientation of the instrument relative the patient
anatomy. This provides the surgeon with different types of data
and/or different views of the same data without having to manually
interact with the system, which is controlled by the tracked
position and orientation of the instrument. This makes the system
more intuitive and flexible to requirements of different
replacement systems and procedures. Different replacement systems
or procedures may require access to different types of data. This
is catered for with embodiments of the system for associating the
pre-operative plan with the tracking data.
[0077] As is illustrated in FIG. 5c, the virtual representation of
the pre-operative plan may comprise at least one of volumetric data
53 (smaller dots), an object representation 54 (solid white), and
grey value data 55 (larger dots). These different types of patient
data may be generated simultaneously or separately by showing and
hiding the different types of data in any of the separate parts
51a, 51b, 51c, 51d of the split window 50. In FIG. 5b, only
volumetric data 53 is shown in all parts 51a, 51b, 51c, 51d of the
split window 50. In FIG. 5d, only grey value data 55 is shown in
all parts 51a, 51b, 51c, 51d of the split window 50. The object
representation may comprise a surface model, a wire frame, or a
solid, generated based on imported volumetric patient data,
implemented using 3D computer graphics, such as the CAD module 42.
Volumetric data 53 may e.g. comprise voxel data obtained from the
pre-operative plan, such as from a stack of CT images or MR data
including the patient anatomy. Grey value data 55 may be calculated
at an arbitrary re-slice plane generated from a stack of CT-images
or from MR data. The virtual representation of the pre-operative
plan may also comprise a virtual representation of an implant
and/or instrument or instrument trajectory, or any other object in
a planned position and orientation relative the patient anatomy in
the preoperative plan.
[0078] Returning to FIG. 5b, at least one display plane 56a, 56b,
56c for generating the virtual representation of the patient data
is fixed relative at least one dimension of the virtual
representation of pre-operative plan or the virtual representation
of the surgical instrument 52. Each display plane 56a, 56b, 56c may
be indicated in each part 51a, 51b, 51c, 51d of the split window 50
in order to assist the operator in understanding the relative
orientation of the data in each part 51a, 51b, 51c, 51d of the
split window 50. All display planes 56a, 56b, 56c may visible, such
as by a frame, also in the first part 51a. In FIG. 5b, the display
planes are not visible in the first part 51a, whereas they are
visible in the first part 51a in the embodiment of FIG. 5d. The
display planes 56a, 56b, 56c may be filled a solid color, such as
black, in order to resemble a tomographic slice of data and/or only
show grey value data within the contours of a specific piece of
anatomy, such as bone.
[0079] In the embodiment of FIG. 5b, the display planes 56a, 56b,
56c are fixed relative a dimension of an implant component 57 in
the pre-operative plan. For example, any of the display planes may
56a, 56b, 56c may be fixed relative a landmark of the implant
component 57 of the pre-operative plan, such as a rotational
indicator of the implant component. Such rotation indicators may
e.g. be provided on a cup for a hip replacement. This means that
the association of the pre-operative plan and display planes is
provided by the type of implant component. Additionally or
alternatively, the dimension may be a longitudinal axis and/or a
position of the implant component, such as a tip or center
thereof.
[0080] The implant component 57 has a fixed planned position and
orientation relative the patient anatomy data. Hence, the display
planes 56a, 56b, 56c may also be fixed relative the patient anatomy
data. The display planes 56a, 56b, 56c provide the viewing
orientations of the virtual representation of the pre-operative
plan in the various parts 51a, 51b, 51c, 51d of the split window
50.
[0081] In some embodiments, the display planes 56a, 56b, 56c are
fixed relative a structure of the patient anatomy, such as a
landmark of the patient anatomy, for example a ridge of the patient
anatomy. A spinous process or a transverse process of a vertebrae
may present such a landmark. Also, a portion of the pelvis, such as
the acetabulum and/or the ridge thereof, may present such a
landmark.
[0082] At least one of the virtual representations of the
pre-operative plan is continuously updated depending on the
tracking data. Also, the virtual representation of the surgical
instrument 52 may be continuously updated in at least one part 51a,
51b, 51c, 51d of the split window 50 depending on the tracking
data. As is illustrated in FIG. 5b, a 3D representation of the
pre-operative plan is provided in a first part 51a of the split
window 50, an axial or transverse representation of the
pre-operative plan is provided in a second part 51b of the split
window 50 providing an axial or transverse viewing orientation or
display plane 56a, a sagittal representation is provided in a third
part 51c of the split window 50 providing a sagittal viewing
orientation or display plane 56b, and a coronal representation is
provided in a fourth part 51d of the split window 50 providing a
coronal viewing orientation or display plane 56c. In other
embodiments, only one or two of the second part 51b, the third part
51c, and the fourth part 51d of the split window 50 are provided in
combination with the 3D representation in the first part 51a of the
split window 50.
[0083] Each display plane 56a, 56b, 56c may be orthogonal to the
other display planes 56a, 56b, 56c. Furthermore, at least one of
the display planes 56a, 56b, 56c may be parallel and/or coincide
with a resliced plane for generating grey values from volumetric
scan data, such as CT data. This is illustrated in FIG. 5c. The
association of the pre-operative plan with the position and
orientation of the surgical instrument may thus provide grey value
data including structures beyond the surfaces that the surgeon can
see while looking at the patient only. The re-slice plane may be
generated at a position and orientation of the pre-operative plan
that corresponds to a position and orientation of the instrument
relative the patient anatomy. Hence, the re-slice plane follows or
tracks the virtual representation of the surgical instrument, which
provides for continues access to the pre-operative plan dependent
on instrument position and orientation without having to manipulate
the system.
[0084] As indicated above, a plurality of orthogonally arranged
display planes 56a, 56b, 56c may be fixed relative at least one
dimension of the virtual representation of the surgical instrument
52 or a portion of the pre-operative plan. The origin of the
display planes 56a, 56b, 56c may e.g. be fixed relative the tip,
center, and/or longitudinal or insertion axis of an implant
component of the pre-operative plan. The position and orientation
of the virtual representations of the surgical instrument 52
relative the plurality of orthogonally arranged display planes 56a,
56b, 56c may be continuously updated. Hence, it is also
continuously updated relative the virtual representations of the
pre-operative plan in each part of said split window depending on
said tracking data. For example, axial or transverse data of the
pre-operative plan may be generated in the second part 51b of the
split window 50 depending on the position and orientation of the
virtual representation of the surgical instrument 52 relative the
virtual representation of the pre-operative plan. For example, as
the virtual representation of the instrument 52 moves along the
coronal display plane 56c, the virtual representation of the
pre-operative plan is continuously updated in the transverse
display plane 56a, such as if the display plane tracks the virtual
representation of the surgical instrument 52. For example, the
axial or transverse display plane 56a may be provided at fixed
position relative the longitudinal direction of the virtual
representation of the surgical instrument 52. The fixed position
may be at the center of the virtual representation of the surgical
instrument 52, such as illustrated in FIG. 5c, or at a
predetermined distance relative the virtual representation of the
surgical instrument 52, such as illustrated in FIG. 5b. The fixed
position may be user defined, fixed in the system, dependent on the
type of surgical procedure and/or type of implant component.
Similarly, as the virtual representation of the instrument 52 moves
along the axial or transverse display plane 56a, and/or the
sagittal display plane 56b, position and orientation of the virtual
representation of the surgical instrument 52 relative the virtual
representation of the pre-operative plan may be continuously
updated in the other display planes 56a, 56b, 56c.
[0085] The position and orientation of the display planes 56a, 56b,
56c may be based on a planned position and/or a planned orientation
of the implant component of the pre-operative plane relative the
patient anatomy data of said pre-operative plan. For example, the
axial or transverse plane 56a may be oriented in the insertion
direction of the implant component. In other embodiments, the axial
or transverse plane 56a is aligned with the axial or transverse
plane of the patient anatomy, for example if the axial or
transverse plane of the patient anatomy is defined during the
pre-operative planning. An indication of the orientation of the
patient anatomy may be included in the pre-operative plan.
[0086] As is illustrated in FIG. 5b, at least one 3D representation
is generated as the virtual representation of the pre-operative
plan in the first part 51a of the split window 50. The 3D
representation may be updated depending on the position of the
virtual representation of the surgical instrument 52. For example,
any of the display planes 56a-56c may be cutting planes. The 3D
representation may be cut or not displayed on one side of the
cutting plane, whereas it is displayed on the other side. At the
same time, a 2D representation as the virtual representation of the
pre-operative plan is generated in the second part 51b of the split
window 50. The 2D representation may comprise volume and/or grey
value data. Each of the 3D representation and the 2D representation
is generated dependent on the tracking data.
[0087] Furthermore, grey value data from the patient anatomy data
of the pre-operative plan may be generated in at least one of said
separate parts 51a-51d of the split window 50 depending on the
tracking data. As is illustrated in FIG. 5d, grey value data may be
generated in any of the parts 51a-51d or the split window 50
relative the position of the virtual representation of the surgical
instrument 52. Furthermore, at least two of grey value data, volume
data, and surface data may be continuously generated based on the
patient anatomy data of the pre-operative plan and in at least one
of the separate parts 51a-51d of the split window 50 depending on
the tracking data. This is illustrated in FIG. 5c, where all types
of data are generated relative the position and orientation the
virtual representation of the surgical instrument 52, such as the
tip thereof. Hence, in some embodiments, the virtual representation
of the surgical instrument 52 relative the virtual representation
of the pre-operative plan may be generated in at least three
orientations in three different parts 51a-51d of the split window
52 simultaneously and depending on the tracking data.
[0088] In some embodiments, orientation settings for at least one
part 51a-51d of the split window 52 are obtained from the
pre-operative plan. This may be user defined during the
pre-operative planning procedure. Hence, the surgical navigation
system may be used by different surgeons having their respective
planning modules but yet do not have to define settings in the CAD
module before commencing surgery using the same surgical navigation
system. The settings may be automatically applied upon importing
the pre-operative plan. Hence, the system is more user-friendly and
intuitive. Alternatively, the settings are set in a user profile
and applied upon logging into the surgical navigation system. The
orientation setting defines the orientation of at least one virtual
representation of the pre-operative plan in at least one part
51a-51d of the split window 50.
[0089] As is illustrated in FIGS. 5b and 5d, an axial or transverse
representation of the pre-operative plan is generated in one part
of the split window 50 and at least one of a coronal representation
and a sagittal representation of the pre-operative plan is
generated in at least one other part of the split window 50 and
depending on the tracking data. The axial or transverse
representation of the pre-operative plan may be continuously
updated depending on the position of the virtual representation of
the surgical instrument 52, as described above. However, the
coronal and/or the sagittal representation may be static, whereas
the position of the virtual representation of the surgical
instrument 52 relative the static representation is continuously
updated depending on the tracking data. Also, the 3D representation
of the pre-operative plan in the first part 51a may be continuously
updated. Grey value data may be continuously updated in the first
part 51a of the split window 50 relative the 3D representation as
well as in the second part 51b of the split window 50, but not in
the other parts 51c-51d of the split window. Hence, an object
representation of the patient anatomy and the virtual
representation of the surgical instrument 52 may be generated in
the first part 51a of the split window 50 depending on the tracking
data. Also, volumetric representation and/or grey value
representation of the patient anatomy and the virtual
representation of the surgical instrument 52 may be generated in
the second part 51b of the split window 50 depending on the
tracking data.
[0090] As is illustrated in FIG. 5c, the object representation as
well as an volumetric and/or grey value representation of the
patient anatomy data and the virtual representation of the surgical
instrument may be generated the first part 51a of the split window
50 depending on the tracking data. The surface representation and
the volumetric and/or grey value representation are at least
partially offset in an axial direction of the patient anatomy.
Hence, an offset is provided between the different representations
of the pre-operative plan. This represents an accuracy indication
of the system, such as to verify the accuracy of a segmentation
process for generating the surface representation. Certain portions
of the patient anatomy may have been classified as a particular
type of anatomy, such as bone tissue, whereas it actually is a
different type of anatomy, such as soft tissue. Presenting both
types of representations allows the surgeon to verify the accuracy
of the segmentation process. The transverse cutting plane in the
first part 51a may track or follow the position of the virtual
representation of the instrument 52, such as a tip thereof, but the
orientation of the transverse cutting plane may follow the
orientation of the patient anatomy.
[0091] FIG. 5e illustrates an embodiment wherein at least one
display plane 56e is fixed relative at least one dimension of the
virtual representation of the surgical instrument 52. In the
illustrated embodiment, it is fixed relative the longitudinal axis,
i.e. the insertion direction of the surgical instrument. Hence, as
the virtual representation of the surgical instrument 52 rotates,
the virtual representation of the pre-operative plan is updated,
such as a transverse representation of the pre-operative plan, as
is illustrated in FIG. 5e. In the illustrated embodiment, only an
object representation is generated. In other embodiments, grey
value data is presented at the transverse cross-section of the
anatomical structure, e.g. such that grey value data is generated
in the window in the transverse plane. This embodiment may be
combined with any of the other embodiments of the split window 50,
such as generated in a part 56a-56d of the split window.
[0092] In still other embodiments the orientation of at least one
display plane is fixed relative the orientation of scan data of the
pre-operative plan, such as the orientation of volumetric data,
e.g. CT slices of DICOM files.
[0093] In some embodiments, enabling and/or disabling the display
planes 56a-56d is initiated from an actuator, such as a push
button, of the tracker 2a-2e. Hence, the surgeon can operate the
system without interacting with a computer running the surgical
navigation system. Furthermore, any of the parts 51a-51d of the
split window 50 may be enabled or disabled depending on a
particular step of the surgical procedure, such as insertion of the
particular implant component, such as a cup or stem of a hip
replacement procedure. The step of the procedure may be indicated
in a graphical user interface or depending on an identified
attachment component.
[0094] The method and system for associating the pre-operative plan
may be used together with the navigation system presented herein.
Hence identity data may be received from at least one tracker 2a-2e
of the navigation system, wherein the tracker identity data is
unique for each tracker 2a-2e in the navigation system. Position
and orientation data of a tracker interface attached to the tracker
interface of an attachment component is received. Calibration data
defining the position and orientation of a portion of the surgical
instrument relative a tracker interface of the attachment component
is obtained. The position and orientation data of the tracker
interface is translated into position and orientation data of the
instrument using the identity data and said calibration data before
generating the virtual representations of the surgical instrument
relative the virtual representation of the patient anatomy. In
other embodiments, the method and system for associating the
pre-operative plan may be used with other navigation systems
wherein the position and orientation of a surgical instrument is
tracked. However, common to these systems is that the virtual
representation of the surgical instrument 52 relative the
pre-operative plan corresponds to the position and orientation of
the surgical instrument relative patient during the operation one
the patient anatomy is referenced. Hence, the virtual
representations of the surgical instrument relative multiple
virtual representations of the pre-operative plan are dependent on
the tracking data, which provides the position and orientation of
the surgical instrument.
[0095] The system for associating a pre-operative plan with
position and orientation of a surgical instrument in a surgical
navigation system comprises a surgical navigation module, such as
the surgical navigation system 40. The system may be configured to
generate a preoperative plan with a virtual representation of
patient anatomy and a planned position and orientation of a
surgical object. The navigation system 41 comprises at least one
tracker attachable to an instrument to be tracked, and a localizer
for tracking at least one of position and orientation of said at
least one tracker, such as is disclosed in embodiments herein. The
at least one tracker may comprise the position transmitter and the
tracker interface for attaching the at least one tracker to the
instrument. The navigation system 41 may be arranged to report
tracking data comprising position and orientation of the tracker to
the surgical navigation module. The surgical navigation module may
be configured to generate tracked position and orientation of the
surgical instrument as virtual representations of the surgical
instrument relative virtual representations of pre-operative plan
in separate parts of a split window depending on the tracking data.
The surgical navigation module may comprise the display 4 and the
computer 5 comprising a processor and memory for running software
instructions for implementing the method for associating the
pre-operative plan with position and orientation of the surgical
instrument in the surgical navigation system 40.
[0096] FIGS. 6a-6d illustrates embodiments of a method for
determining at least one of position and orientation of the
instrument using the navigation system 41 including at least a
first and a second tracker 102e, 102b. The method may be
implemented e.g. by a computer, such as computer 5. Position and
orientation data of the first tracker 102e, which is attached to a
calibration station 101 in a known fixed position and orientation
relative a calibration location of the calibration station 101, may
be generated. Position and orientation data identifying position
and orientation of the tracker interface of the second tracker 102b
may be obtained while the second tracker 102b is removably attached
to the instrument using the tracker interface of the second tracker
102b. The position and orientation of the instrument relative the
second tracker may be determined using the position and orientation
data of the first tracker 102e, the position and orientation data
of the tracker interface of the second tracker 102b, and the known
fixed position and orientation of the calibration location relative
the position and orientation of the first tracker 102e.
[0097] The position and orientation data of the first tracker 102e
may comprise position and orientation of a tracker interface of the
first tracker 102e obtained while the tracker interface of the
first tracker 102e is attached to the tracker interface of the
calibration station 101. In other embodiments, the calibration
station 101 has an integrated tracker. However, having a tracker
interface makes the calibration station independent in the
navigation system, which makes it more flexible and the navigation
system exchangeable and possible to upgrade to new navigation
technology without replacing the calibration station.
[0098] The position and orientation data of the second tracker 102b
may be received while the second tracker 102b is attached to the
tracker interface of the attachment component, which in turn is
attached to the instrument. Utilizing an attachment component for
attaching the tracker makes the system flexible, and the tracker
may be retrofitted to any instrument. Hence, the surgeon may
continue to use the instrument with which he is familiar while
benefitting of enhanced information via the navigation system.
[0099] Tracker identity data for at least the second tracker 102b,
which uniquely identifies the second 102b tracker in the navigation
system 41 may be received while obtaining the position and
orientation data of the tracker interface of the second tracker
102b, as will also be further discussed below. Also, the determined
position and orientation of the instrument relative the second
tracker may be stored in a database together with the tracker
identity data of the second tracker 102b, and preferably with
instrument data identifying a specific combination of an instrument
and attachment component. Hence, it is not necessary to calibrate
the specific combination of an instrument and attachment component
every time the tracker is attached to the combination. Rather the
combination may be identified in the surgical navigation system 40
and associated with a particular tracker. The identification may be
made by an operator of the system. Re-calibration is only necessary
if the attachment component has been detached from the instrument
from a previous calibration.
[0100] A system may be used for calibrating the position and
orientation of the instrument within the navigation system. As
discussed above, a first tracker 101e is attachable to the
calibration station 101 and the second tracker 101b attachable to
the attachment component. The calibration station 101 has a
calibration location for receiving a portion of the instrument. At
least one attachment component is provided for attaching the second
tracker 102b to the instrument. At least the second tracker 102b
comprises the tracker interface for attaching the second tracker
102b to a tracker interface of the attachment component.
[0101] The first tracker 102e may comprise a tracker interface for
attaching the first tracker 102e to a tracker interface of the
calibration station 101. The tracker interface of the calibration
station 101 has a fixed position and orientation relative the
calibration location.
[0102] The tracker interface of the attachment component may be
identical to the tracker interface of the calibration station. This
makes the system accurate and reliable. If the tracker interfaces
comprises an anti-rotational feature, the tracker cannot be
accidentally rotated. However, in other embodiments the tracker
interface of the calibration station 101 comprises an
anti-rotational feature, and the second tracker 102b is
rotationally attachable relative the tracker interface of the
attachment component. Hence, it is easier to orient the tracker
102b relative the instrument such that it is in a suitable
orientation relative the localizer during surgery.
[0103] FIGS. 6a-6d illustrates embodiments of the calibration
station 101 having a tracker interface 124 identical to the tracker
interface 44 of the attachment components, as discussed above.
Hence, a tracker 102e is attachable to the calibration station in a
fixed position and orientation relative the calibration
station.
[0104] FIGS. 6a-6d also illustrates embodiments of the method for
determining at least one of position and orientation of the
instrument, such as determining the position of a particular
attachment component 110 and instrument 103b combination. The
method may be implemented by the CAD module 42 to transform
position and orientation of a tracker to position and orientation
of at least a portion of the instrument 103b. The calibration
station 101 is associated with a known calibration location 108 for
an end effector of a surgical instrument, such as a tip of the
surgical instrument, a plane of the surgical instrument, a center
of rotation of the instrument, and/or a combination thereof.
[0105] The tracker interface 124 of the calibration station 101 has
a fixed predetermined position and orientation relative the
calibration location 108. The position and orientation of the
calibration location relative the position and orientation of the
tracker interface 124 of the calibration station 101 is known to
the surgical navigation system 30, such as to the CAD module 42.
The tracker interface 124 of the calibration station 101 may be
defined as the origin for the calibration, relative which other
components positions and orientations are reported.
[0106] Calibrating the position and orientation of the instrument
103b may be made using two trackers 102b, 102c. Each tracker 102b,
102c comprises a tracker interface, as has been discussed above.
Hence, each tracker 102b, 102c comprises a trackable surface within
the navigation system 41. The instrument interface of the
attachment component 110 is attachable to the surgical instrument
103b. A first tracker 102e is attachable to the tracker interface
124 of the calibration station 101. A second tracker 102b is
attachable to the tracker interface of the attachment component
110.
[0107] FIG. 6a illustrates the system uncalibrated, wherein the
first and second trackers 102e, 102b are in a first coordinate
system x.sub.1, y.sub.1, z.sub.1 known to the navigation system;
the calibration station is in a second coordinate system x.sub.2,
y.sub.2, z.sub.2; and the surgical instrument is in a third
coordinate system x.sub.3, y.sub.3, z.sub.3. The position and
orientation of the first tracker 102e or the second tracker 102b
may be defined as origin for the calibration. The following
embodiments are described with regard to the first tracker 102e,
i.e. its tracker interface, as providing the origin. However, the
second tracker 102b may be defined as origin for the calibration in
other embodiments. Since the origin is predefined, the navigation
system only needs to report the position and orientation of the
tracker interface of the second tracker 102b relative origin.
Identifying the position and orientation of the first tracker 102e
identifies the origin. The position and orientation of the first
tracker attached to a calibration station in a known fixed position
and orientation relative the calibration location 108 of the
calibration station 101 does not have to be reported to the CAD
module, which may set this value to a default value. The relative
position and orientation between the first tracker 1020e and the
relative position and orientation between the first tracker, i.e.
the origin for calibration, and the tracker interface of the second
tracker 102b may be obtained from the navigation system. Data of
the relative position and orientation may be obtained in the CAD
module. The position and orientation of the instrument is
determined using the relative position and orientation between the
first tracker, i.e. origin, and the tracker interface of the second
tracker 102b, and the known fixed position and orientation of the
calibration location relative the position and orientation of the
first tracker, i.e. relative origin. These may be calculated based
on the values of the known origin, the known position and
orientation of the calibration location relative the position and
orientation of the first tracker, i.e. relative origin, and the
obtained relative position and orientation between the first
tracker, i.e. origin, and the tracker interface of the second
tracker 102b.
[0108] Returning to FIG. 6a, the first, second and third coordinate
systems are uncalibrated. The first coordinate system is the
coordinate system of the navigation system. In a first step
illustrated in FIGS. 6a-6b, the second coordinate system x.sub.2,
y.sub.2, z.sub.2 is aligned or coordinated with the first
coordinate system x.sub.1, y.sub.1, z.sub.1 by attaching the first
tracker 102e to the tracker interface of the calibration station
101. This identifies the origin for the calibration, wherein the
position of the tracker interface 124 of the calibration station
101 is known in the coordinate system x.sub.1, y.sub.1, z.sub.1 of
the navigation system 30, as is illustrated in FIG. 6b. The tracker
interface 124 of the calibration station 101 is now located at the
origin for the calibration, identified by the first tracker 102e.
Also, the third coordinate system x.sub.3, y.sub.3, z.sub.3 is
aligned or coordinated with the first coordinate system x.sub.1,
y.sub.1, z.sub.1 by attaching the second tracker 102b to the
tracker interface of the attachment component 110 having its
instrument interface attached relative the surgical instrument
103b. In some embodiments, the instrument interface is fixed to the
instrument in two dimensions, such as the x and z dimensions, and
has a predetermined stop position in the third dimension, such as
the y dimension. Such predetermined stop position may be a stop
member of the instrument and/or instrument interface such that the
attachment component cannot move any further in one direction along
the third dimension. For example, the attachment component may be
attached to a rotatable shaft, such as the shaft of a reamer or
planar, such that it may move along the shaft but not be tilted
relative the shaft. Calibration occurs when the attachment
component is at the stop member, such that the surgeon always can
return to the calibrated position of the attachment component
relative the instrument. Attaching the attachment component 110 to
the surgical instrument 103b is not illustrated. Hence, the
position and orientation of the tracker interface of the attachment
component 110 is known in the coordinate system x.sub.1, y.sub.1,
z.sub.1 of the navigation system 30, as is illustrated in FIG. 6b.
However, the position and orientation of the end-effector of the
surgical instrument in the coordinate system x.sub.1, y.sub.1,
z.sub.1 of the navigation system 30, i.e. relative origin, is still
unknown.
[0109] FIGS. 6c-6d illustrates coordinating or registering the
position and orientation of the surgical instrument 103b in the
coordinate system x.sub.1, y.sub.1, z.sub.1 of the navigation
system 30. This is done by positioning the end effector of the
instrument 103b at the calibration location 108. The end effector
may be the portion of the instrument that is to be tracked in the
CAD module 42. The end effector may be a surface of the instrument,
such as a surface of a reamer, a tip of a drill or other instrument
etc. It may also be a center of rotation of an instrument, such as
the center of a reamer or a planar. In the illustrated embodiment,
the end effector is the center of rotation of a reamer. As is
illustrated in FIG. 6c, the end effector of the instrument is
positioned at the calibration location 108. Next, the position and
orientation of the second tracker 102b relative the position and
orientation of the first tracker 102e, such as the position and
orientation of their tracker interfaces, are registered by the
navigation system. In some embodiments, only the position and
orientation of the tracker interface of the second tracker 102b
relative the position and orientation of the tracker interface of
the first tracker 102e is reported. This is sufficient when the
origin for calibration is predefined as the location of the tracker
interface of the first tracker 102e. The position and orientation
of the tracker interface of the second tracker 102b may be obtained
by the CAD module 42 from the navigation system. In other
embodiments, the positions and orientations of the tracker
interface of the first as well as of the second tracker are
obtained.
[0110] Since the position and orientation of the calibration
location 108 relative the first tracker 102e, i.e. relative the
calibration origin, is known, the position and orientation of the
second tracker 102b relative the end-effector of the surgical
instrument 103b can be determined and stored, such as in a
transformation table or database. This may also be stored together
with tracker identity and instrument identity, for example if
multiple tools are used at the same time, or if the tracker is
connected to different instruments during various steps of the
surgical procedure. Hence, the coordinate systems are coordinated,
and the position and orientation of the end-effector of the
surgical instrument 103b may be continuously determined by tracking
and translating the position and orientation of the second tracker
102b, i.e. the position and orientation of the tracker interface
thereof.
[0111] The calibration method may be used for any instrument and
any replacement system. The system may be used with only two
trackers in order to track position and orientation of any
instrument. Hence, the system is extremely flexible and may easily
be adapted to new replacement systems. Furthermore, an intermediate
attachment interface that has a predefined shape means that the
surgical navigation system 31 can be replaced by new navigation
technology. The navigation system simply needs to report the
position of the tracker interface relative an origin of the system,
such as for calibration.
[0112] As discussed above, to calibrate the position and
orientation of the surgical instrument 103b in the first coordinate
system, the end-effector is positioned at the calibration location
108. The calibration location may be a recess or a protrusion in or
at a surface of the calibration station 101, such that it has a
substantially fixed position at one point and/or in one plane, e.g.
the x.sub.1-z.sub.1 plane, illustrated in FIGS. 6c-6d.
[0113] In some embodiments, the position of the tracker interface
of the second tracker 102b may be registered while moving the
surgical instrument, and thus the attachment component and the
second tracker 102b attached thereto. The attached components may
be moved in at least a second plane, such as the x.sub.1-y.sub.1
plane and/or y.sub.1-z.sub.1 plane, and while the end-effector is
positioned at the calibration location 108, i.e. has a relatively
fixed position in one point or one plane, such as the
x.sub.1-z.sub.1 plane. Multiple positions and orientations of the
tracker interface of the second tracker 102b are registered while
moving in the second plane. At the same time, the position and
orientation of the first tracker 102e is registered. Based on these
registered positions and orientations, the position and orientation
of the center of rotation of the second tracker 102b, and thus the
center of rotation of the end-effector, may be calculated. Also,
the position and orientation of the axis of the surgical instrument
103b relative the tracker interface of the second tracker 102b may
be calculated.
[0114] In FIG. 6d, the surgical object 93 is shown in a single
position for illustrative purposes. As an alternative calibration
method, the surgical instrument may be positioned perpendicularly
to a calibration plane of the calibration station 101 while the
position and orientation of the tracker interface of the second
tracker 102b is registered. The calibration plane has a fixed
orientation relative the tracker interface of the calibration
station 101, i.e. relative calibration origin. Hence, the position
and orientation of the axis of the surgical instrument 103b within
the first coordinate system may be calculated using the calibration
plane and calibration location 108. The calibration plane may be
the top surface 109 of the calibration station, as is illustrated
in FIG. 6d. The instrument may be attached to a calibration support
that has a shape that is complementary to the shape of surfaces at
the calibration location, such as part-spherical component with
legs extending along the calibration plane and that supports the
instrument during calibration and keeps it stable in the plane.
Three such legs may be sufficient for fixed angular relationship
between the longitudinal axis of the instrument and the calibration
plane during the calibration process.
[0115] The navigation system may comprise at least one tracker
attachable to an instrument to be tracked and a localizer for
tracking at least one of position and orientation of said at least
one tracker. The at least one tracker may comprise a position
transmitter and a tracker interface for attaching the at least one
tracker to the instrument, as has been discussed above. Position
and orientation of position transmitter may be used by the
navigation system to obtain position and orientation of the tracker
interface of the tracker. The positional and orientation
relationship between the position transmitter and the tracker
interface is predetermined and known to the navigation system,
which may be configured to report the position and orientation of
the tracker within the navigation system.
[0116] Embodiments comprise a method for tracking position and
orientation of the instrument using the navigation system 41. The
method may be implemented in the surgical navigation system 41,
such as a by a computer running the CAD module 42. As is discussed
above, the navigation system may include a plurality of trackers
2a-2e and a localizer for identifying the position and orientation
of the tracker. Each tracker may have a unique identity in the
navigation system, such as an identification no. The tracker
identity data is unique for each tracker in the navigation system.
Identity data, such as the identification no. may be reported by
the tracker 2a-2e, such as using a wireless transmitter, e.g. using
wireless radio technology, such as WiFi or Bluetooth technology.
The identity is reported to the navigation system. Furthermore, the
position and orientation of the tracker interface of the tracker
2a-2e for with identity no. has been received may be determined by
the navigation system. Sending the identity data from the tracker
may be triggered, such as initiated by a user activating an
actuator. The navigation system may determine the position and
orientation of the tracker upon receiving the identity data.
According to the method, identity data from at least one tracker of
the navigation system is received. Also, position and orientation
data of the tracker interface being attached to the tracker
interface of the attachment component is obtained. The identity
data and the related position an orientation data of the reporting
tracker may be used to translate the position and orientation data
of the tracker interface of the reporting tracker into position and
orientation data of the instrument. The identity data may be used
to query a database to obtaining calibration data defining the
position and orientation of a portion of the instrument, such as
discussed above. Then, the position and orientation of the
instrument may be determined based on the calibration data. The
calibration data may be obtained as discussed above. Similarly, the
method may comprise attaching the tracker to the attachment
component, and the attachment component to the instrument, as has
been discussed above.
[0117] FIG. 7 illustrates an embodiment of a tracker 202 according
to embodiments of the invention. The tracker 202 has a position
transmitter arranged in a fixed and predetermined position relative
the tracker interface 213. The position transmitter may comprise as
a plurality of active and/or passive markers arranged in a
predetermined relationship and/or having predetermined shapes. In
this embodiment, the position transmitter comprises an active
position transmitter, which comprises a plurality of LEDs 219a-219f
arranged in a known pattern relative the tracker interface 213 of
the tracker 202. The markers have a known position and orientation
relative the origin of the coordinate system of the tracker 202,
which is located at its tracker interface 213 according to
embodiments described herein. The localizer may in this embodiment
comprise a camera to capture the position of the position
transmitter, such as light transmitted by the LEDs 219a-219f, which
a processor thereof may utilize to determine the position and
orientation of the of the tracker interface 213. Transmission of
position information may be triggered by actuators integrated in
the housing of the tracker (not illustrated). A system for
obtaining the position based on active markers is e.g. disclosed in
WO91/16598, which is incorporated herein by reference for all
purposes. Another example is disclosed in disclosed in U.S. Pat.
No. 5,440,392, which is incorporated herein by reference for all
purposes. Another embodiment of an optical navigation system is
disclosed in U.S. Pat. No. 6,166,809, which is incorporated herein
by reference for all purposes, with which both position and
orientation may be obtained. Embodiments of the present invention
may also be used with inertial navigation systems, wherein sensors
such as accelerometers and gyros are arranged in a known position
and orientation relative the tracker interface 213 of the tracker
202. As is illustrated in FIG. 7 and according to embodiments of
the present invention, the coordinate system is located at the
tracker interface 213, e.g. such that the y axis is extending along
the longitudinal axis of the tracker interface 213, and is located
at the center of the tracker interface 213. The x and z axes are
extending parallel to a plane formed by the tip or free end of the
tracker interface 213. The markers have a known position and
orientation relative the origin of the coordinate system of the
tracker 202, which is located at its tracker interface 213. This
means anything can be aligned and tracked relative the tracker
interface 213.
[0118] FIGS. 8a-8c, and 11a-11b illustrate front, side, and
perspective views, respectively, of an embodiment of the tracker
interface of the attachment component. As discussed above, the
tracker interface of the attachment component may comprise a
protrusion 226 extending from a base 227. The base 227 has a larger
cross-sectional diameter than the protrusion 226 as measured
perpendicularly relative the longitudinal axis of the tracker
interface. This means that the base 227 has a top surface 240 (not
illustrated in FIG. 8c) facing the towards the tracker interface of
the tracker. The protrusion 226 is in this embodiment semi-circular
with a radially facing non-circular surface 241. The non-circular
surface 241 may be a generally flat or planar surface extending in
a plane that is perpendicular to the top surface 240 of the base
227. Furthermore, the tracker interface comprises a locking feature
242, for locking engagement of the tracker interface to a tracked
surface of the tracker, such as the tip of the tracker interface
213 of the tracker 202. In this embodiment, the locking feature 242
is a semi-circular recess provided in the non-circular surface 241.
The locking feature 242 may extend perpendicularly relative the
longitudinal axis of the tracker interface and parallel to the top
surface 240 of the base 227. In this embodiment, the locking
feature 242 only extends partially around the circumference of the
protrusion 226. In other embodiments, the locking feature 242
extends around the entire circumference of the protrusion 226,
which may improve stability and thus accuracy of tracking of the
attachment component.
[0119] FIGS. 9a-9c illustrate attaching the tracker interface 225
of the tracker to the tracker interface of the attachment
component. In this embodiment, the tracker interface 225 of the
tracker comprises a chuck. The chuck comprises a boss 230 with a
generally flat or planar end surface 231, which may be part of or
form the tip of the tracker, and a recess (not illustrated). The
end surface 231 extends perpendicularly relative the longitudinal
axis of the recess of the tracker interface 225. Furthermore, the
chuck comprises a locking element that comprises an eccentric rod
234 connected to a level arm or actuator 235. The eccentric rod 234
is arranged perpendicularly relative the longitudinal axis of the
recess of the tracker interface 225. The level arm is arranged to
swivel the eccentric rod 234, which is rotatably arranged in the
tracker interface 225 of the tracker.
[0120] As is illustrated in FIG. 9a, the tracker interface 225,
i.e. the recess, of the tracker 202 is configured to fit over the
protrusion 226 of the tracker interface of the attachment
component. The recess and protrusion may fit in a location fit. The
semi-circular surface of the protrusion 226 has a shape that
substantially corresponds to a shape of an inner radially facing
surface extending in the longitudinal direction of the tracker
interface 225 of the tracker. The semi-circular surfaces are
arranged and sized to abut each other, at least in a locked
position of the tracker interfaces.
[0121] As is illustrated in FIG. 9b, when the tracker interface 225
of the tracker is fully seated, it fits over the protrusion 226 of
the tracker interface of the attachment component, as is
illustrated with phantom lines. Also, the end surface 231 of the
tracker interface 225 of the tracker may abut the top surface 240
of the tracker interface of the attachment component. Also the
locking feature 242 faces the locking element. Before being locked,
the locking element is positioned such that the maximum distance
between the eccentric rod and the semi-circular surface of the
recess is slightly larger than the maximum diameter of the
protrusion 226 measured at the longitudinal axis of the
non-circular surface 241 perpendicularly to the semi-circular
surface of the protrusion 226. In this position, the tracker
interface 225 of the tracker is aligned with the tracker interface
of the attachment component, as is illustrated with the unlocked
pad lock symbol.
[0122] As is illustrated with a locked pad lock symbol in FIG. 9c,
the tracker interfaces may be locked to each other when the lever
arm 235 is pushed or swivel to a locked position, such that the
eccentric rod 234 is positioned within the locking feature 242.
Hence, the locking element is positioned such that the maximum
distance between the eccentric rod and the semi-circular surface of
the recess is smaller than the maximum diameter of the protrusion
226 measured at the longitudinal axis of the non-circular surface
241 perpendicularly to the semi-circular surface of the protrusion
226. Furthermore, the tracker interface of the tracker may be
pushed towards the tracker interface of the attachment component in
the locked position, such as by the eccentric rod 234 engaging the
locking feature 242. This may e.g. be provided by the eccentric rod
engaging at least a portion of the semi-circular recess provided in
the non-circular surface 241, such as at an upper or lower surface
thereof. Hence, the tracker interfaces are locked in a position
such that the tracked surface of the tracker abuts a tracked
surface of the attachment component. Thereby the tracker interfaces
share a common origin, as is illustrated with the y/z axes (x axis
extending into the plane of FIG. 9c). Hence, tracking position and
orientation of the tracker interface of the tracker also tracks the
attachment component when locked to each other.
[0123] Furthermore, the tracker interface 213 of the tracker 202 is
a calibrated tracker interface, wherein its exact position and
orientation in the navigation system is predefined and known and
does not need to be calibrated. The position and orientation within
the navigation system may be pre-calibrated during manufacturing,
such as against a master calibration tool, e.g. including an
interface corresponding to the tracker interface of the attachment
component, which is mounted in a fixed relationship relative
calibration markers. Reading the position and orientation of the
position transmitter relative the coordinate system of the master
tool calibration markers may pre-calibrate or characterize the
tracker interface of the tracker to the master tool. This may be
done prior to delivery of the navigation system.
[0124] The calibration station 101 described with regard to FIGS.
6a-6d is a calibration object that may be stationary, i.e. it is
not attached to the instrument. As such, the calibration object may
have a platform, which is configured to be positioned stably on a
surface during the calibration procedure, e.g. such that the
instrument can be positioned at a predefined position relative the
calibration location. This provides for a simple and stable
positioning of the instrument relative the calibration station. The
instrument does not need to be fastened to the stationary
calibration station during the calibration procedure. However, the
navigation system may only include a single position tracker 6,
such as a single camera or a receiver of accelerometer and gyro
data from the trackers. For example, the calibration may be done
shortly before a surgery commences in order to assure accuracy of
the system. That means that the position tracker 6 is arranged such
that the patient will be located within the operational range of
the position tracker 6, which may cover a portion of the operating
table and a relatively small volume surrounding the operating
table. During calibration, the trackers also need to be within the
operational range of the position tracker 6. This has the
consequence that it may in certain situations and/or for certain
navigation systems be inconvenient or impractical to arrange the
calibration station 101 in the operational range of the position
tracker 6, which is arranged in an optimal position for surgery but
not necessarily for calibration. This may e.g. be the case for
optical navigation systems, but not for inertial navigations
systems, which are not limited by a field of view of a camera.
[0125] FIGS. 10a-10e and 11a-11c disclose embodiments of
calibration objects 101a, 101b, 101c, 101d that are mobile
calibration stations, as is envisaged within the scope of the
calibration station as discussed with regard to FIG. 4, i.e. for
calibrating location, such as position and/or orientation of the
instrument 103b, 14a within a navigation system. The mobile
calibration station 101a-101d may comprise elements as disclosed
with regard to FIGS. 6a-6d, and the same features are denoted with
the same reference numerals. Hence, the mobile calibration object
101a-101d can be used for calibrating location of any of the
instruments 103b illustrated in FIG. 6a-6d, which may comprise a at
least a portion of a reamer instrument, e.g. a reamer shaft as
illustrated in FIGS. 10a, and 10c-10e, and the instrument 14a,
which may comprise a cup inserter, as illustrated in FIG. 10b. The
instruments illustrated in FIGS. 10a-10e and 11a-11c are only
examples, other examples as disclosed herein as well as other
instruments or portions thereof may be subject of the embodiments
disclosed herein for calibrating their location within the
navigation system, such as an instrument positioning a stem of a
hip implant.
[0126] As the previous embodiments discussed above, the embodiments
of FIGS. 10a-10e and 11a-11c may be used together with a first
tracker 102e, and a second tracker 102b. The embodiments of the
tracker interface for attaching a tracker 102e of the navigation
system to the mobile calibration objects 101a-101d may correspond
to the tracker interface 124 discussed above, such as with regard
to FIGS. 6a-6d and will not be discussed again with regard to FIGS.
10a-10e and 11a-11c except with regard to alternative embodiments.
Similarly, the attachment components 10a-10d and 110 discussed
above may equally be used together with the embodiments of FIGS.
10a-10e and 11a-11c and will not be discussed again with regard to
FIGS. 10a-10e and 11a-11c except with regard to alternative
embodiments.
[0127] FIGS. 10a-10e and 11a-11c illustrate embodiments of
calibration objects 101a-101d that may be mobile. As is illustrated
in FIGS. 11a-11c, the calibration object 101a, 101b comprises a
calibration body 111a, 111b having a calibration location 108a,
108b for receiving a portion of the instrument 013b in a predefined
position, in the same way as the embodiments of FIGS. 6a-6d. The
tracker interface has a predetermined location relative the
calibration location 108a, 108b. The tracker interface may comprise
the protrusion 226 extending from the base 227, the top surface
240, the radially facing non-circular surface 241, and/or the
locking feature 242, which may be a semi-circular recess provided
in the non-circular surface 241, as has been discussed above.
Furthermore, the tracker interface of the calibration object
101a-101d may comprise the origin for the calibration. The origin
may have a predetermined location, such as fixed position and
orientation, relative the calibration location 108a, 108b.
[0128] As is illustrated in FIG. 11a, the embodiments of FIG.
10a-10d, 11a-11b, as well as the embodiments of FIGS. 6a-6d, the
calibration location 108a, 108b may comprise an instrument
attachment member configured for releasable fastening of the
calibration object 101a-101d to an instrument, such as in a
predetermined position and/or orientation. Hence, the calibration
body 111a, 111b may be releasably fastened in the rotational and/or
axial direction relative the instrument 14a, 103a. Hence, the
tracker 102b, when attached to the calibration object 101a-101d, is
also fixed in the rotational and/or axial direction relative the
instrument 14a, 103a. Surgical instruments, such as instrument 14a,
103a, may have an attachment interface in order to switch between
different sizes of end effectors and/or for releasable fastening of
an implant. The instrument attachment member may be configured for
releasable attachment to the attachment interface of any such
surgical instrument. For example, the instrument attachment member
of the embodiment of FIG. 11a comprises pins forming a cross, that
hooks of the instrument attachment interface may engage. The size
of the pins corresponds to the size of the hooks. The pins may be
formed in the center of a ring shaped body, which comprises the
tracker interface attached on its surface projecting outwardly
relative the center. The pins provide for axial and rotational
attachment of the instrument to the calibration location 108a,
108b. Similarly, the embodiment of FIG. 11b-11c comprises a surface
with at least one recesses and/or protrusion forming the instrument
attachment member. The embodiment of FIG. 11c comprises two
recesses. Each recess may comprise a snap fit attachment interface,
e.g. comprising protrusions extending in the radial direction of
the recess. Such a snap fit attachment interface may be fixed in
the axial direction, but may not necessarily be fixed in the
rotation direction, such as if a position of the tool is to be
guided but not an orientation of the tool. The recess of the
surface may alternatively or additionally comprise a press-fit
and/or friction fit connection. Hence, the calibration object
101a-101d, such as its instrument attachment member, may comprise
at least one surface that has a shape that is complementary to a
shape of a surface of the instrument attachment interface.
[0129] In the embodiment of FIG. 11a, the calibration body 111
comprises a circular member, such as ring shaped member, with the
instrument attachment member in the center. Such a calibration body
may be useful for a tool such as a reamer.
[0130] In the embodiment of FIGS. 11b-11c, the calibration body 111
comprises a part-spherical member, such as half-spherical, with the
attachment member at a substantially flat surface of the
part-spherical member. Such a calibration body may be useful for a
tool such as a cup inserter.
[0131] Returning to FIGS. 10a-10e, the calibration object 101a-101d
provides for a more flexible calibration method. The calibration
object 101a-101d may be temporarily fixedly attached or fastened to
the surgical instrument 14a, 103a, and the trackers 102a, 102e
attached to their respective tracker interfaces. Then, the operator
can grab the instrument 14a, 103a with a single hand, move the
entire unit including the attachment component 110, the calibration
object 101a-101d, and the trackers 102a, 102e, and hold the unit
within the operational range of the position tracker 6. Hence, the
operator can prepare the instrument 14a, 103a for calibration at
one location, and than only be within the operational range of the
position tracker 6 for a short period of time. Furthermore, this
means that one operator may prepare the navigation system for
surgery while another operator prepares the instrument(s) for
calibration. Calibration may conveniently be carried out also when
the position tracker 6 is positioned for surgery relative an
operating table. Hence, the calibration process as well as the
entire navigation system is more flexible, which is useful for any
navigation system, but particularly for navigation systems with
more limited operational range, such as optical navigation
systems.
[0132] As is illustrated in FIG. 10a, the system may be calibrated
with the surgical tool, such as a drilling machine, attached to the
surgical instrument 103b. Alternatively, the system may be
calibrated with the surgical tool detached from the surgical
instrument, such as illustrated in FIG. 10c.
[0133] FIGS. 10d-10e illustrate embodiments wherein the calibration
object 101c, 101d is attached to a tool-engaging end of the
instrument 103b, such as for engaging a chuck of a surgical tool,
e.g. a chuck of a drilling machine. The tool-engaging end of the
instrument 103b may have an antirational engagement member for
antirational engagement with the surgical tool. The calibration
object 101c, 101b may be configured with complementary surfaces
corresponding to the chuck of the surgical tool, such that the
calibration object 101c, 101d may be attached at a predetermined
location relative an end-effector end of the instrument 103b.
Hence, the location of the calibration object 101c, 101d, when
temporarily attached to the tool-engaging end of the instrument
102b, relative the location of the end-effector end is
predetermined and known. Knowing the shape of the end-effector, the
relative position relative to the end-effector, when attached to
the end-effector end, may also predetermined and known. This
information may be stored in a database.
[0134] The calibration object 101c, 101d may have a body that
comprises the tracker interface for attachment to the tracker and
an instrument attachment interface for engagement to the
tool-engaging end of the instrument 103b. The instrument attachment
interface has a fixed predetermined location relative the
end-effector end of the instrument 103b. Hence, by calibrating
against the tool-engaging end, the location of the end-effector end
of the instrument 103b may be determined and tracked using the
tracker 102b attached to the attachment components 10a-10d and 110
as discussed above.
[0135] As is illustrated in FIGS. 10d, 10e, the tracker interface
of the calibration body 101c, 101d can be arranged at an arbitrary
position relative the instrument 103b. In the embodiment of FIG.
10d, the tracker interface is arranged parallel to the longitudinal
axis of the instrument 103b. In the embodiment of FIG. 10e, the
tracker interface is arranged non-parallel to the longitudinal axis
of the instrument 103b, such as substantially perpendicular to the
longitudinal axis of the instrument 103b. Hence, the orientation of
the tracker interfaces relative the instrument 103b may be
optimized for visibility to the position tracker 6, wherein the
calibration process is optimized.
[0136] The calibration object 101a, 101b may comprise the body
111a, 111b, which may comprises at least one of the calibration
location 108a, 108b and the tracker interface. The calibration
location 108a, 108b may be integrally formed with the body.
Additionally or alternatively, the tracker interface of the
calibration body may be integrally formed with the calibration body
111a, 111b. Hence, the calibration location 108a, 108b and/or the
tracker interface of the calibration object 101a, 101b, as well as
the calibration body 111a, 111b, may be formed as a single unit,
such as in a single material. Alternatively, the tracker interface
is detachably attached to the calibration body at a predetermined
location relative the calibration location 108a, 108b in the same
way as the tracker interface 13d relative the body 11d of FIG. 2e.
Hence, the tracker interface may be detachably attached to the
calibration body 111a, 111b at a predetermined location relative
the calibration location 108a, 108b.
[0137] As described above, the system for calibrating position and
orientation of an instrument within a navigation system may
comprise a calibration object, such as a stationary and/or mobile
calibration body, wherein the tracker interface of the calibration
object is a first tracker interface, the attachment component
comprises a tracker interface, which is a second tracker interface.
The navigation system comprises the first tracker 102e attachable
to the first tracker interface and a second tracker 102b attachable
to the second tracker interface. The first tracker interface and
the second tracker interface may be identical.
[0138] As will be apparent, the features and attributes of the
specific embodiments disclosed above may be combined in different
ways to form additional embodiments, all of which fall within the
scope of the present disclosure.
[0139] Conditional language used herein, such as, among others,
"can," "could," "might," "may," "e.g.," and the like, unless
specifically stated otherwise, or otherwise understood within the
context as used, is generally intended to convey that certain
embodiments include, while other embodiments do not include,
certain features, elements and/or states. Thus, such conditional
language is not generally intended to imply that features, elements
and/or states are in any way required for one or more embodiments
or that one or more embodiments necessarily include logic for
deciding, with or without author input or prompting, whether these
features, elements and/or states are included or are to be
performed in any particular embodiment.
[0140] Any process descriptions, elements, or blocks in the flow
diagrams described herein and/or depicted in the attached figures
should be understood as potentially representing modules, segments,
or portions of code which include one or more executable
instructions for implementing specific logical functions or steps
in the process. Alternate implementations are included within the
scope of the embodiments described herein in which elements or
functions may be deleted, executed out of order from that shown or
discussed, including substantially concurrently or in reverse
order, depending on the functionality involved, as would be
understood by those skilled in the art.
[0141] The processes and systems described herein may be performed
on or encompass various types of hardware, such as computer
systems. In some embodiments, computer, display, and/or input
device, may each be separate computer systems, applications, or
processes or may run as part of the same computer systems,
applications, or processes--or one of more may be combined to run
as part of one application or process--and/or each or one or more
may be part of or run on a computer system. A computer system may
include a bus or other communication mechanism for communicating
information, and a processor coupled with the bus for processing
information. The computer systems may have a main memory, such as a
random access memory or other dynamic storage device, coupled to
the bus. The main memory may be used to store instructions and
temporary variables. The computer systems may also include a
read-only memory or other static storage device coupled to the bus
for storing static information and instructions. The computer
systems may also be coupled to a display, such as a CRT or LCD
monitor. Input devices may also be coupled to the computer system.
These input devices may include a mouse, a trackball, or cursor
direction keys.
[0142] Each computer system may be implemented using one or more
physical computers or computer systems or portions thereof. The
instructions executed by the computer system may also be read in
from a computer-readable medium. The computer-readable medium may
be a CD, DVD, optical or magnetic disk, laserdisc, carrier wave, or
any other medium that is readable by the computer system. In some
embodiments, hardwired circuitry may be used in place of or in
combination with software instructions executed by the processor.
Communication among modules, systems, devices, and elements may be
over a direct or a switched connection, and wired or wireless
networks or connections, via directly connected wires, or any other
appropriate communication mechanism. The communication among
modules, systems, devices, and elements may include handshaking,
notifications, coordination, encapsulation, encryption, headers,
such as routing or error detecting headers, or any other
appropriate communication protocol or attribute. Communication may
also be messages related to HTTP, HTTPS, FTP, TCP, IP, ebMS
OASIS/ebXML, secure sockets, VPN, encrypted or unencrypted pipes,
MIME, SMTP, MIME Multipart/Related Content-type, SQL, etc.
[0143] Any appropriate 3D graphics processing may be used for
displaying or rendering including processing based on OpenGL,
Direct3D, Java 3D, etc. Whole, partial, or modified 3D graphics
packages may also be used, such packages including 3DS Max,
SolidWorks, Maya, Form Z, Cybermotion 3D, or any others. In some
embodiments, various parts of the needed rendering may occur on
traditional or specialized graphics hardware. The rendering may
also occur on the general CPU, on programmable hardware, on a
separate processor, be distributed over multiple processors, over
multiple dedicated graphics cards, or using any other appropriate
combination of hardware or technique.
[0144] As will be apparent, the features and attributes of the
specific embodiments disclosed above may be combined in different
ways to form additional embodiments, all of which fall within the
scope of the present disclosure.
[0145] Conditional language used herein, such as, among others,
"can," "could," "might," "may," "e.g.," and the like, unless
specifically stated otherwise, or otherwise understood within the
context as used, is generally intended to convey that certain
embodiments include, while other embodiments do not include,
certain features, elements and/or states. Thus, such conditional
language is not generally intended to imply that features, elements
and/or states are in any way required for one or more embodiments
or that one or more embodiments necessarily include logic for
deciding, with or without author input or prompting, whether these
features, elements and/or states are included or are to be
performed in any particular embodiment.
[0146] Any process descriptions, elements, or blocks in the flow
diagrams described herein and/or depicted in the attached figures
should be understood as potentially representing modules, segments,
or portions of code which include one or more executable
instructions for implementing specific logical functions or steps
in the process. Alternate implementations are included within the
scope of the embodiments described herein in which elements or
functions may be deleted, executed out of order from that shown or
discussed, including substantially concurrently or in reverse
order, depending on the functionality involved, as would be
understood by those skilled in the art.
[0147] All of the methods and processes described above may be
embodied in, and fully automated via, software code modules
executed by one or more general purpose computers or processors,
such as those computer systems described above. The code modules
may be stored in any type of computer-readable medium or other
computer storage device. Some or all of the methods may
alternatively be embodied in specialized computer hardware.
[0148] It should be emphasized that many variations and
modifications may be made to the above-described embodiments, the
elements of which are to be understood as being among other
acceptable examples. All such modifications and variations are
intended to be included herein within the scope of this disclosure
and protected by the following claims.
[0149] The present invention has been described above with
reference to specific embodiments. However, other embodiments than
the above described are equally possible within the scope of the
invention. Different method steps than those described above may be
provided within the scope of the invention. The different features
and steps of the invention may be combined in other combinations
than those described. The scope of the invention is only limited by
the appended patent claims.
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