U.S. patent application number 10/084291 was filed with the patent office on 2002-12-26 for surgical navigation systems and processes for high tibial osteotomy.
Invention is credited to Carson, Christopher P..
Application Number | 20020198451 10/084291 |
Document ID | / |
Family ID | 26955127 |
Filed Date | 2002-12-26 |
United States Patent
Application |
20020198451 |
Kind Code |
A1 |
Carson, Christopher P. |
December 26, 2002 |
Surgical navigation systems and processes for high tibial
osteotomy
Abstract
Systems and processes for tracking anatomy, instrumentation, and
references, and rendering images and data related to them in
connection with surgical operations, particularly high tibial
osteotomy ("HTO"). These systems and processes are accomplished by
using a computer to intraoperatively obtain images of body parts
and to register, navigate, and track surgical instruments.
Inventors: |
Carson, Christopher P.;
(Memphis, TN) |
Correspondence
Address: |
CHIEF PATENT COUNSEL
SMITH & NEPHEW, INC.
1450 BROOKS ROAD
MEMPHIS
TN
38116
US
|
Family ID: |
26955127 |
Appl. No.: |
10/084291 |
Filed: |
February 27, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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60271818 |
Feb 27, 2001 |
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60355899 |
Feb 11, 2002 |
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Current U.S.
Class: |
600/424 ;
600/426; 600/427; 606/130 |
Current CPC
Class: |
A61F 2/4657 20130101;
A61B 34/20 20160201; A61B 2034/2055 20160201; A61B 2034/252
20160201; A61B 90/10 20160201; A61F 2002/4632 20130101; A61B 34/10
20160201; A61B 2034/256 20160201; A61F 2/4684 20130101; A61B 34/25
20160201; A61B 2034/105 20160201; A61B 2034/102 20160201; A61B
2034/254 20160201; A61F 2/389 20130101; A61B 2090/376 20160201;
A61B 17/70 20130101; A61B 2034/2068 20160201; A61B 2090/3916
20160201; A61F 2002/30616 20130101; A61B 2034/2072 20160201; A61F
2002/30892 20130101; A61B 2090/3983 20160201; A61F 2/38 20130101;
A61F 2/3859 20130101; A61B 90/36 20160201; A61B 2034/107
20160201 |
Class at
Publication: |
600/424 ;
600/426; 600/427; 606/130 |
International
Class: |
A61B 005/05; A61B
019/00 |
Claims
What is claimed is:
1. A process for performing high tibial osteotomy surgical
operations on portions of a tibia, comprising: (a) obtaining at
least one image of a body part forming a portion of a knee joint
with an imager, wherein the body part and the imager are each
attached to a fiducial capable of being tracked by at least one
position sensor; (b) registering a surgical instrument adapted to
assist the surgeon in shaping bone during high tibial osteotomy,
which instrument is attached to a fiducial capable of being tracked
by at least one position sensor; (c) using a computer which
receives signals from the at least one sensor, tracking position
and orientation of the surgical instrument relative to the body
part; (d) generating and displaying on a monitor associated with
the computer a visual image of the instrument properly positioned
and oriented relative to the body part; (e) navigating the surgical
instrument relative to the body part and attaching the surgical
instrument to the body part according to the image; and (f)
modifying the body part using the surgical instrument attached to
the body part; and (g) assessing performance of the knee joint
using images displayed on said monitor.
2. The process of claim 1, further comprising registering a body
part by intraoperatively designating at least one point on the body
part with a probe, wherein the probe is attached to a fiducial
capable of being tracked by said at least one position sensor.
3. The process of claim 1, wherein the body part comprises one of a
femur and a tibia.
4. The process of claim 1, wherein the imager comprises one of a
C-arm fluoroscope, a CT scanner, and an MRI machine.
5. The process of claim 1, wherein the fiducials comprise one of
active fiducials, passive fiducials and hybrid active/passive
fiducials.
6. The process of claim 1, wherein the position tracking sensors
comprise one of infrared sensors, electromagnetic sensors,
electrostatic sensors, light sensors, sound sensors, and
radiofrequency sensors.
7. The process of claim 1, wherein the surgical instrument
comprises a pivot pin and a cutting jig.
8. The process of claim 1, further comprising: (a) discontinuing
tracking of the surgical instrument using the fiducial attached to
a drill sleeve; and (b) initiating tracking of the surgical
instrument using the fiducial attached to the body part on which
the surgical instrument is installed.
9. The process of claim 1, further comprising: (a) performing soft
tissue balancing tests while the computer continues to track the
fiducials; (b) using data generated by the computer to assess
alignment and stability of the surgical instrument and the knee
joint; and (c) changing the angle of the surgical instrument to
adjust alignment and stability of the knee joint.
10. A process for performing high tibial osteotomy surgical
operations on portions of a tibia comprising: (a) obtaining at
least one image of a body part forming a portion of a knee joint
with an imager, wherein the body part and the imager are each
attached to a fiducial capable of being tracked by at least one
position sensor; (b) registering a surgical instrument adapted to
assist the surgeon in shaping bone during high tibial osteotomy,
which instrument is attached to a fiducial capable of being tracked
by at least one position sensor; (c) using a computer which
receives signals from the at least one sensor, tracking position
and orientation of the surgical instrument relative to the body
part; (d) generating and displaying on a monitor associated with
the computer a visual image of the instrument properly positioned
and oriented relative to the body part; (e) navigating the
instrument relative to the body part and attaching the instrument
to the body part according to the image; (f) discontinuing tracking
of the instrument using the fiducial attached to the instrument;
(g) initiating tracking of the instrument using the fiducial
attached to the body part on which the instrument is installed; (h)
generating and displaying on the monitor a visual image of the
instrument properly positioned and oriented relative to the body
part; (i) modifying the body part using the instrument attached to
the body part; and (j) assessing performance of the knee joint
using images displayed on said monitor.
11. A process for performing high tibial osteotomy surgical
operations on portions of a tibia comprising: (a) obtaining at
least one image of a body part forming a portion of a knee joint
with an imager, wherein the body part and the imager are each
attached to a fiducial capable of being tracked by at least one
position sensor; (b) registering a surgical instrument adapted to
assist the surgeon in shaping bone during high tibial osteotomy,
which instrument is attached to a fiducial capable of being tracked
by at least one position sensor; (c) using a computer which
receives signals from the at least one sensor, tracking position
and orientation of the instrument relative to the body part; (d)
generating and displaying on a monitor associated with the computer
a visual image of the instrument properly positioned and oriented
relative to the body part; (e) navigating the instrument relative
to the body part and attaching the instrument to the body part
according to the image; (f) discontinuing tracking of the
instrument using the fiducial attached to the instrument; (g)
initiating tracking of the instrument using the fiducial attached
to the body part on which the instrument is installed; (h)
generating and displaying on the monitor a visual image of the
instrument properly positioned and oriented relative to the body
part; (i) performing soft tissue balancing tests while the computer
continues to track the fiducials; (j) using data generated by the
computer to assess alignment and stability of the knee joint with
the surgical instrument attached; and (k) changing the angle of the
surgical instrument to adjust alignment and stability. (l)
modifying the body part using the instrument attached to the body
part; and (m) assessing performance of the knee joint using images
displayed on said monitor.
12. A system for performing high tibial osteotomy surgical
operations on portions of a tibia comprising: (a) an imager for
obtaining an image of a tibia, wherein the imager and the tibia are
each attached to a fiducial capable of being tracked by a position
sensor; (b) at least one position sensor adapted to track position
of said fiducials; (c) a computer adapted to store at least one
image of the tibia and to receive information from said at least
one sensor in order to track position and orientation of said
fiducials and thus the tibia; (d) a pivot pin adapted to be
attached to a tibia using a drill sleeve in a high tibial osteotomy
procedure, said drill sleeve attached to a fiducial, whereby the
position of the pivot pin is capable of being tracked by said
sensor and the position and orientation of the pin is capable of
being tracked by said computer; and (e) a monitor adapted to
receive information from the computer in order to display at least
one image of said pivot positioned and oriented relative to the
tibia for navigation and positioning of the pin in the tibia.
13. A system for performing high tibial osteotomy surgical
operations on portions of a tibia comprising: (a) an imager for
obtaining an image of a tibia, wherein the imager and the tibia are
each attached to a fiducial capable of being tracked by a position
sensor; (b) at least one position sensor adapted to track position
of said fiducials; (c) a computer adapted to store at least one
image of the tibia and to receive information from said at least
one sensor in order to track position and orientation of said
fiducials and thus the tibia; (d) a cutting jig adapted to be
positioned over a pivot pin in a high tibial osteotomy procedure,
whereby the position of the cutting jig is capable of being tracked
by said computer according to the position and orientation of the
pivot pin; and (e) a monitor adapted to receive information from
the computer in order to display at least one image of said cutting
jig positioned and oriented relative to the tibia for navigation
and positioning of the cutting jig on the tibia.
14. A system for performing high tibial osteotomy surgical
operations on portions of a tibia comprising: (a) an imager for
obtaining an image of a tibia, wherein the imager and the tibia are
each attached to a fiducial capable of being tracked by a position
sensor; (b) at least one position sensor adapted to track position
of said fiducials; (c) a computer adapted to store at least one
image of the tibia and to receive information from said at least
one sensor in order to track position and orientation of said
fiducials and thus the tibia; (d) a pivot pin adapted to be
attached to a tibia using a drill sleeve in a high tibial osteotomy
procedure, said drill sleeve attached to a fiducial, whereby the
position of the pivot pin is capable of being tracked by said
sensor and the position and orientation of the pin is capable of
being tracked by said computer; (e) a cutting jig adapted to be
positioned over a pivot pin, whereby the position of the cutting
jig is capable of being tracked by said computer according to the
position and orientation of the pivot pin; and (f) a monitor
adapted to receive information from the computer in order to
display at least one image of at least one of said pivot pin and
cutting jig, positioned and oriented relative to the tibia for
navigation and positioning of the pin and the cutting jig on the
tibia.
Description
RELATED APPLICATION DATA
[0001] This document claims the benefit of U.S. S No. 60/271,818,
filed Feb. 27, 2001 entitled "Image Guided System for Arthroplasty"
and U.S. S No. 60/355,899, filed Feb. 11, 2002 entitled "Surgical
Navigation Systems and Processes," which documents are incorporated
herein by this reference.
FIELD OF THE INVENTION
[0002] This invention generally relates to use in certain osteotomy
surgery, of systems and processes for tracking anatomy, implements,
instrumentation, trial implants, implant components and virtual
constructs or references, and rendering images and data related to
them in connection with orthopedic, surgical and other operations.
Anatomical structures and such items may be attached to or
otherwise associated with fiducial functionality, and constructs
registered in position using fiducial functionality, whose position
and orientation can be sensed and tracked by systems and according
to processes of the present invention in three dimensions. Such
structures, items and constructs can be rendered onscreen properly
positioned and oriented relative to each other using associated
image files, data files, image input, or other sensory input, based
on the tracking. Such systems and processes, among other things,
allow surgeons to navigate and perform surgical operations using
images that reveal interior portions of the body combined with
computer generated or transmitted images that show surgical
implements, instruments, trials, implants, and other devices
located and oriented properly relative to the body part. Such
systems and processes allow, among other things, more accurate and
effective resection of bone, placement and assessment of trial
implants and joint performance, and placement and assessment of
performance of actual implants and joint performance.
BACKGROUND
[0003] In unicompartmental arthritis of the knee, high tibial
osteotomy ("HTO") is a treatment of choice. HTO is a common
treatment for tibia vara (bow legs). An osteotomy is a surgical
procedure to realign a bone in order to change the biomechanics of
a joint, especially to change the force transmission through a
joint. HTO is a corrective surgical procedure in which the upper
part of the tibia is resected so that the lower limb can be
realigned. The purpose of HTO is to realign the deformed tibial
plateau to shift the load bearing into the unaffected compartment
of the knee.
[0004] There are three types of HTO: closing wedge, open wedge, and
cylindrical barrel. The closing wedge HTO is the most common
procedure and it involves realignment of the bone by removal of a
lateral wedge of bone from the proximal tibia. The wedge is first
planned on a frontal-plane standing X-ray by drawing a wedge of the
desired correction angle, where the wedge's upper plane is parallel
to the tibial plateau and the lower plane is above the tibial
tubercle. Ideally, the wedge will produce a hinge of cortical bone
approximately 2-5 mm in thickness.
[0005] Upon surgical exposure of the proximal tibia, the correction
is mapped to the bones of the patient with a ruler or a jig system.
The surgery is then performed either free-hand or with the
assistance of Kirschner wires (K-wires) as cutting guides.
Intraoperative fluroscopic X-ray is often employed for verification
before and during the procedure.
[0006] Unlike total knee arthroplasty ("TKA"), HTO preserves the
joint's original cartilaginous surfaces and corrects the
fundamental mechanical problem of the knee. This advantage is
especially important to young active patients because TKA has a
greater probability of earlier failure in active patients.
[0007] However, problems remain in HTO performance. A major
difficulty with HTO is that the outcome is sometimes not acceptably
predictable because it is difficult for a surgeon to attain the
desired correction angle. Current instrumentation cannot accurately
produce the desired resection from preoperative plans. On average,
the margin of error is reported between 6.degree. and 14.degree..
Technical difficulties also arise from the use of fluoroscopy, such
as image-intensifier nonlinearities and distortions that compromise
accuracy, and parallax errors that can provide misleading angular
and positional guidance. Additionally, the use of continual
fluoroscopic imaging is sometimes required thus exposing the
surgeon and assistants to radiation.
[0008] Several providers have developed and marketed improved
cutting jigs that have improved the accuracy of the resection in
HTO. However, extensive fluoroscopic time is still needed for the
positioning of the jigs. Inaccurate pin placement can also affect
the accuracy of the alignment of the resection, thus increasing
shear stresses across the osteotomy. Other providers have developed
various forms of imaging systems for use in surgery. Many are based
on CT scans and/or MRI data or on digitized points on the anatomy.
Other systems align preoperative CT scans, MRIs or other images
with intraoperative patient positions. A preoperative planning
system allows the surgeon to select reference points and to
determine the final implant position. Intraoperatively, the system
calibrates the patient position to that preoperative plan, such as
using a "point cloud" technique, and can use a robot to make
femoral and tibial preparations.
[0009] Accordingly, there is a continuing need for an
intraoperative planning system and process for performing HTO's
with minimal fluroscopic exposure. There is also a need for a
system and process that allows improved accuracy in performing the
wedge resection and in placing pins or staples.
SUMMARY
[0010] The present invention is applicable not only for knee
repair, reconstruction or replacement surgery, but also repair,
reconstruction or replacement surgery in connection with any other
joint of the body as well as any other surgical or other operation
where it is useful to track position and orientation of body parts,
non-body components and/or virtual references such as rotational
axes, and to display and output data regarding positioning and
orientation of them relative to each other for use in navigation
and performance of the operation.
[0011] Systems and processes according to one embodiment of the
present invention use position and/or orientation tracking sensors
such as infrared sensors acting stereoscopically or otherwise to
track positions of body parts, surgery-related items such as
implements, instrumentation, trial prosthetics, prosthetic
components, and virtual constructs or references such as rotational
axes which have been calculated and stored based on designation of
bone landmarks. Processing capability such as any desired form of
computer functionality, whether standalone, networked, or
otherwise, takes into account the position and orientation
information as to various items in the position sensing field
(which may correspond generally or specifically to all or portions
or more than all of the surgical field) based on sensed position
and orientation of their associated fiducials or based on stored
position and/or orientation information. The processing
functionality correlates this position and orientation information
for each object with stored information regarding the items, such
as a computerized fluoroscopic imaged file of a femur or tibia, a
wire frame data file for rendering a representation of an
instrumentation component, trial prosthesis or actual prosthesis,
or a computer generated file relating to a rotational axis or other
virtual construct or reference. The processing functionality then
displays position and orientation of these objects on a screen or
monitor, or otherwise. Thus, systems and processes according to one
embodiment of the invention can display and otherwise output useful
data relating to predicted or actual position and orientation of
body parts, surgically related items, implants, and virtual
constructs for use in navigation, assessment, and otherwise
performing surgery or other operations.
[0012] As one example, images such as fluoroscopy images showing
internal aspects of the femur and tibia can be displayed on the
monitor in combination with actual or predicted shape, position and
orientation of surgical implements, instrumentation components,
trial implants, actual prosthetic components, and rotational axes
in order to allow the surgeon to properly position and assess
performance of various aspects of the tibia being repaired,
reconstructed or replaced. The surgeon may navigate tools,
instrumentation, trial prostheses, actual prostheses and other
items relative to the tibia in order to perform HTO's more
accurately, efficiently, and with better alignment and
stability.
[0013] Systems and processes according to the present invention can
also use the position tracking information and, if desired, data
relating to shape and configuration of surgical related items and
virtual constructs or references in order to produce numerical data
which may be used with or without graphic imaging to perform tasks
such as assessing performance of trial prosthetics statically and
throughout a range of motion, appropriately modifying tissue such
as ligaments to improve such performance and similarly assessing
performance of actual prosthetic components which have been placed
in the patient for alignment and stability. Systems and processes
according to the present invention can also generate data based on
position tracking and, if desired, other information to provide
cues on screen, aurally or as otherwise desired to assist in the
surgery such as suggesting certain bone modification steps based on
performance of components as sensed by systems and processes
according to the present invention.
[0014] According to a preferred embodiment of systems and processes
according to the present invention, at least the following steps
are involved:
[0015] 1. Obtain appropriate images such as fluoroscopy images of
appropriate body parts such as femur and tibia, the imager being
tracked in position via an associated fiducial whose position and
orientation is tracked by position/orientation sensors such as
stereoscopic infrared (active or passive) sensors according to the
present invention.
[0016] 2. Register tools, instrumentation and other items to be
used in surgery, each of which corresponds to a fiducial whose
position and orientation can be tracked by the position/orientation
sensors.
[0017] 3. Locating and registering body structure such as
designating points on the femur and tibia using a probe associated
with a fiducial in order to provide the processing functionality
information relating to the body part such as rotational axes.
[0018] 4. Navigating and positioning instrumentation such as
cutting instrumentation in order to modify bone, at least partially
using images generated by the processing functionality
corresponding to what is being tracked and/or has been tracked,
and/or is predicted by the system, and thereby resecting bone
effectively, efficiently and accurately.
[0019] 5. Navigating and positioning items such as pivot pins and,
if desired, at the appropriate time discontinuing tracking the
position and orientation of the items using the fiducial that is
attached to the item and starting to track that position and
orientation using the body part fiducial on which the item is
installed.
[0020] 6. Assessing alignment and stability of pivot pins and
joint, both statically and dynamically as desired, using images of
the body parts in combination with images of the pivot pins or
trial components while conducting appropriate rotation,
anterior-posterior drawer and flexion/extension tests and
automatically storing and calculating results to present data or
information which allows the surgeon to assess alignment and
stability.
[0021] 7. Adjusting pivot pins if necessary and adjusting trial
components as desired for acceptable alignment and stability.
[0022] 8. Fixing cutting jigs to the body part at the desired angle
as calculated by the system.
[0023] 9. Assessing alignment and stability of the wedge resection
and joint by use of some or all tests mentioned above and/or other
tests as desired, adjusting if desired, and otherwise verifying
acceptable alignment, stability and performance of the wedge
resection, both statically and dynamically.
[0024] This process, or processes including it or some of it may be
used in any total or partial joint repair, reconstruction or
replacement, including knees, hips, shoulders, elbows, ankles and
any other desired joint in the body.
[0025] Systems and processes according to the present invention
represent significant improvement over other previous systems and
processes. For instance, systems which use CT and MRI data
generally require the placement of reference frames pre-operatively
which can lead to infection at the pin site. The resulting 3D
images must then be registered, or calibrated, to the patient
anatomy intraoperatively. Current registration methods are less
accurate than the fluoroscopic system. These imaging modalities are
also more expensive. Some "imageless" systems, or non-imaging
systems, require digitizing a large number of points to define the
complex anatomical geometries of the knee at each desired site.
This can be very time intensive resulting in longer operating room
time. Other imageless systems determine the mechanical axis of the
knee by performing an intraoperative kinematic motion to determine
the center of rotation at the hip, knee, and ankle. This requires
placement of reference frames at the iliac crest of the pelvis and
in or on the ankle. This calculation is also time consuming at the
system must find multiple points in different planes in order to
find the center of rotation. This is also problematic in patients
with pathologic conditions. Ligaments and soft tissues in the
arthritic patient are not normal and thus will give a center of
rotation that is not desirable for normal knees.
[0026] Robotic systems require expensive CT or MRI scans and also
require pre-operative placement of tibial markers, usually the day
before surgery, or pre-operative construction of tibia surface
models. These systems are also much slower, almost doubling
operating room time and expense.
[0027] None of these systems can effectively track pivot pins
during a range of motion and calculate the relative angle of the
wedge resection, among other things. Also, none of them currently
make suggestions on the appropriate angle or surgical techniques
for wedge resection based on reference axes and correction
algorithms. Additionally, none of these systems currently track the
patella.
[0028] An object of certain aspects of the present invention is to
use computer processing functionality in combination with imaging
and position and/or orientation tracking sensors to present to the
surgeon during surgical operations visual and data information
useful to navigate, track and/or position implements,
instrumentation, and other items and virtual constructs relative to
the human body in order to improve performance of a repaired,
replaced or reconstructed bone.
[0029] Another object of certain aspects of the present invention
is to use computer processing functionality in combination with
imaging and position and/or orientation tracking sensors to present
to the surgeon during surgical operations visual and data
information useful to assess performance of a tibia and certain
items positioned therein, for stability, alignment and other
factors, and to instrumentation and resection in order to improve
such performance of a repaired, reconstructed or replaced bone.
[0030] Another object of certain aspects of the present invention
is to use computer processing functionality in combination with
imaging and position and/or orientation tracking sensors to present
to the surgeon during surgical operations visual and data
information useful to show any or all predicted position and
movement of instrumentation and other items and virtual constructs
relative to the human body in order to select appropriate angles,
resect bone accurately, effectively and efficiently, and thereby
improve performance of a repaired, replaced or reconstructed
bone.
[0031] Other objects, features and advantages of the present
invention are apparent with respect to the remainder of this
document.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] FIG. 1 is a schematic view of a particular embodiment of
systems and processes according to the present invention.
[0033] FIG. 2 is a view of a knee prepared for surgery to which
fiducials according to one embodiment of the present invention have
been attached.
[0034] FIG. 3 is a view of a portion of a leg prepared for surgery
according to the present invention with a C-arm for obtaining
fluoroscopic images associated with a fiducial according to one
embodiment of the present invention.
[0035] FIG. 4 is a fluoroscopic image of free space rendered on a
monitor according to one embodiment of the present invention.
[0036] FIG. 5 is a fluoroscopic image of femoral head obtained and
rendered according one embodiment of the present invention.
[0037] FIG. 6 is a fluoroscopic image of a knee obtained and
rendered according to one embodiment of the present invention.
[0038] FIG. 7 is a fluoroscopic image of a tibia distal end
obtained and rendered according to one embodiment of the present
invention.
[0039] FIG. 8 is a fluoroscopic image of a lateral view of a knee
obtained and rendered according to one embodiment of the present
invention.
[0040] FIG. 9 is a fluoroscopic image of a lateral view of a knee
obtained and rendered according to one embodiment of the present
invention.
[0041] FIG. 10 is a fluoroscopic image of a lateral view of a tibia
distal end obtained and rendered according to one embodiment of the
present invention.
[0042] FIG. 11 shows a probe according to one embodiment of the
present invention being used to register a surgically related
component for tracking according to one embodiment of the present
invention.
[0043] FIG. 12 shows a probe according to one embodiment of the
present invention being used to designate landmarks on bone
structure for tracking according one embodiment of the present
invention.
[0044] FIG. 13 is a screen face produced according to one
embodiment of the present invention during designation of landmarks
to determine a femoral mechanical axis.
[0045] FIG. 14 is a screen face produced according to one
embodiment of the present invention during designation of landmarks
to determine an epicondylar axis.
[0046] FIG. 15 is a screen face produced according to one
embodiment of the present invention during designation of landmarks
to determine an anterior-posterior axis.
[0047] FIG. 16 is a screen face according to one embodiment of the
present invention showing mechanical and other axes which have been
established according to one embodiment of the present
invention.
[0048] FIG. 17 is another screen face according to one embodiment
of the present invention showing mechanical and other axes which
have been established according to one embodiment of the present
invention.
[0049] FIG. 18 shows a pivot pin according to one embodiment of the
present invention being placed in the tibia.
[0050] FIG. 19 shows tibial cutting jigs according to one
embodiment of the present invention.
[0051] FIG. 20 shows proximal and distal cutting jigs according to
one embodiment of the present invention being placed on the tibia
around the pivot pin.
[0052] FIG. 21 is a screen face produced according to one
embodiment of the present invention which assists in navigation
and/or placement of a distal cutting jig.
[0053] FIG. 22 shows a tibia that has been stapled after a closed
wedge resection.
DETAILED DESCRIPTION
[0054] Systems and processes according to a preferred embodiment of
the present invention use computer capacity, including standalone
and/or networked, to store data regarding spatial aspects of
surgically related items and virtual constructs or references
including body parts, implements, instrumentation, trial
components, prosthetic components and rotational axes of body
parts. Any or all of these may be physically or virtually connected
to or incorporate any desired form of mark, structure, component,
or other fiducial or reference device or technique which allows
position and/or orientation of the item to which it is attached to
be sensed and tracked, preferably in three dimensions of
translation and three degrees of rotation as well as in time if
desired. In a preferred embodiment, orientation of the elements on
a particular fiducial varies from one fiducial to the next so that
sensors according to the present invention may distinguish between
various components to which the fiducials are attached in order to
correlate for display and other purposes data files or images of
the components. In a referred embodiment, "fidicuals" are reference
frames each containing at least three, preferably four, sometimes
more, reflective elements such as spheres reflective of lightwave
or infrared energy, or active elements such as LED's. In a
preferred embodiment of the present invention, some fiducials use
reflective elements and some use active elements, both of which may
be tracked by preferably two, sometimes more infrared sensors whose
output may be processed in concert to geometrically calculate
position and orientation of the item to which the fiducial is
attached.
[0055] Position/orientation tracking sensors and fiducials need not
be confined to the infrared spectrum. Any electromagnetic,
electrostatic, light, sound, radiofrequency or other desired
technique may be used. Alternatively, each item such as a surgical
implement, instrumentation component, trial component, implant
component or other device may contain its own "active" fiducial
such as a microchip with appropriate field sensing or
position/orientation sensing functionality and communications link
such as spread spectrum RF link, in order to report position and
orientation of the item. Such active fiducials, or hybrid
active/passive fiducials such as transponders can be implanted in
the body parts or in any of the surgically related devices
mentioned above, or conveniently located at their surface or
otherwise as desired. Fiducials may also take the form of
conventional structures such as a screw driven into a bone, or any
other three dimensional item attached to another item, position and
orientation of such three dimensional item able to be tracked in
order to track position and orientation of body parts and
surgically related items. Hybrid fiducials may be partly passive,
partly active such as inductive components or transponders which
respond with a certain signal or data set when queried by sensors
according to the present invention.
[0056] Systems and processes according to a preferred embodiment of
the present invention employ a computer to calculate and store
reference axes of body components such as in a HTO for example, the
mechanical axis of the femur and tibia. From these axes such
systems track the position of the instrumentation and osteotomy
guides so that bone resections will locate the implant position
optimally, usually aligned with the mechanical axis. Furthermore,
during trial reduction of the knee, the systems provide feedback on
the balancing of the ligaments in a range of motion and under
varus/valgus, anterior/posterior and rotary stresses and can
suggest or at least provide more accurate information than in the
past about which ligaments the surgeon should release in order to
obtain correct balancing, alignment and stability. Systems and
processes according to the present invention can also suggest
modifications to implant size, positioning, and other techniques to
achieve optimal kinematics. Systems and processes according to the
present invention can also include databases of information
regarding tasks such as ligament balancing, in order to provide
suggestions to the surgeon based on performance of test results as
automatically calculated by such systems and processes.
[0057] FIG. 1 is a schematic view showing one embodiment of a
system according to the present invention and one version of a
setting according to the present invention in which surgery on a
knee, in this case a High Tibial Osteotomy, may be performed.
Systems and processes according to the present invention can track
various body parts such as tibia 12 and femur 10 to which fiducials
of the sort described above or any other sort may be implanted,
attached, or otherwise associated physically, virtually, or
otherwise. In the embodiment shown in FIG. 1, fiducials 14 are
structural frames some of which contain reflective elements, some
of which contain LED active elements, some of which can contain
both, for tracking using stereoscopic infrared sensors suitable, at
least operating in concert, for sensing, storing, processing and/or
outputting data relating to ("tracking") position and orientation
of fiducials 14 and thus components such as 10 and 12 to which they
are attached or otherwise associated. Position sensor 16, as
mentioned above, may be any sort of sensor functionality for
sensing position and orientation of fiducials 14 and therefore
items with which they are associated, according to whatever desired
electrical, magnetic, electromagnetic, sound, physical, radio
frequency, or other active or passive technique. In the preferred
embodiment, position sensor 16 is a pair of infrared sensors
disposed on the order of a meter, sometimes more, sometimes less,
apart and whose output can be processed in concert to provide
position and orientation information regarding fiducials 14.
[0058] In the embodiment shown in FIG. 1, computing functionality
18 can include processing functionality, memory functionality,
input/output functionality whether on a standalone or distributed
basis, via any desired standard, architecture, interface and/or
network topology. In this embodiment, computing functionality 18 is
connected to a monitor on which graphics and data may be presented
to the surgeon during surgery. The screen preferably has a tactile
interface so that the surgeon may point and click on screen for
tactile screen input in addition to or instead of, if desired,
keyboard and mouse conventional interfaces. Additionally, a foot
pedal 20 or other convenient interface may be coupled to
functionality 18 as can any other wireless or wireline interface to
allow the surgeon, nurse or other desired user to control or direct
functionality 18 in order to, among other things, capture
position/orientation information when certain components are
oriented or aligned properly. Items 22 such as trial components,
instrumentation components may be tracked in position and
orientation relative to body parts 10 and 12 using fiducials
14.
[0059] Computing functionality 18 can process, store and output on
monitor 24 and otherwise various forms of data which correspond in
whole or part to body parts 10 and 12 and other components for item
22. For example, in the embodiment shown in FIG. 1, body parts 10
and 12 are shown in cross-section or at least various internal
aspects of them such as bone canals and surface structure are shown
using fluoroscopic images. These images are obtained using a C-arm
attached to a fiducial 14. The body parts, for example, tibia 12
and femur 10, also have fiducials attached. When the fluoroscopy
images are obtained using the C-arm with fiducial 14, a
position/orientation sensor 16 "sees" and tracks the position of
the fluoroscopy head as well as the positions and orientations of
the tibia 12 and femur 10. The computer stores the fluoroscopic
images with this position/orientation information, thus correlating
position and orientation of the fluoroscopic image relative to the
relevant body part or parts. Thus, when the tibia 12 and
corresponding fiducial 14 move, the computer automatically and
correspondingly senses the new position of tibia 12 in space and
can correspondingly move implements, instruments, references,
trials and/or implants on the monitor 24 relative to the image of
tibia 12. Similarly, the image of the body part can be moved, both
the body part and such items may be moved, or the on screen image
otherwise presented to suit the preferences of the surgeon or
others and carry out the imaging that is desired. Similarly, when
an item 22 such as a pivot pin that is being tracked moves, its
image moves on monitor 24 so that the monitor shows the item 22 in
proper position and orientation on monitor 24 relative to the femur
10. The pin 22 can thus appear on the monitor 24 in proper or
improper alignment with respect to the mechanical axis and other
features of the femur 10, as if the surgeon were able to see into
the body in order to navigate and position the pin 22 properly.
[0060] The computer functionality 18 can also store data relating
to configuration, size and other properties of items 22 such as
implements, instrumentation, trial components, implant components
and other items used in surgery. When those are introduced into the
field of position/orientation sensor 16, computer functionality 18
can generate and display overlain or in combination with the
fluoroscopic images of the body parts 10 and 12, computer generated
images of implements, instrumentation components, trial components,
implant components and other items 22 for navigation, positioning,
assessment and other uses.
[0061] Additionally, computer functionality 18 can track any point
in the position/orientation sensor 16 field such as by using a
designator or a probe 26. The probe also can contain or be attached
to a fiducial 14. The surgeon, nurse, or other user touches the tip
of probe 26 to a point such as a landmark on bone structure and
actuates the foot pedal 20 or otherwise instructs the computer 18
to note the landmark position. The position/orientation sensor 16
"sees" the position and orientation of fiducial 14 "knows" where
the tip of probe 26 is relative to that fiducial 14 and thus
calculates and stores, and can display on monitor 24 whenever
desired and in whatever form or fashion or color, the point or
other position designated by probe 26 when the foot pedal 20 is hit
or other command is given. Thus, probe 26 can be used to designate
landmarks on bone structure in order to allow the computer 18 to
store and track, relative to movement of the bone fiducial 14,
virtual or logical information such as mechanical axis 28, medial
laterial axis 30 and anterior/posterior axis 32 of femur 10, tibia
12 and other body parts in addition to any other virtual or actual
construct or reference.
[0062] Systems and processes according to an embodiment of the
present invention such as the subject of FIGS. 2-22, can use the
so-called FluoroNAV system and software provided by Medtronic
Sofamor Danek Technologies. Such systems or aspects of them are
disclosed in U.S. Pat. Nos. 5,383,454; 5,871,445; 6,146,390;
6,165,81; 6,235,038 and 6,236,875, and related (under 35 U.S.C.
Section 119 and/or 120) patents, which are all incorporated herein
by this reference. Any other desired systems can be used as
mentioned above for imaging, storage of data, tracking of body
parts and items and for other purposes.
[0063] The FluoroNav system requires the use of reference frame
type fiducials 14 which have four and in some cases five elements
tracked by infrared sensors for position/orientation of the
fiducials and thus of the body part, implement, instrumentation,
trial component, implant component, or other device or structure
being tracked. Such systems also use at least one probe 26 which
the surgeon can use to select, designate, register, or otherwise
make known to the system a point or points on the anatomy or other
locations by placing the probe as appropriate and signaling or
commanding the computer to note the location of, for instance, the
tip of the probe. The FluoroNav system also tracks position and
orientation of a C-arm used to obtain fluoroscopic images of body
parts to which fiducials have been attached for capturing and
storage of fluoroscopic images keyed to position/orientation
information as tracked by the sensors 16. Thus, the monitor 24 can
render fluoroscopic images of bones in combination with computer
generated images of virtual constructs and references together with
implements, instrumentation components, trial components, implant
components and other items used in connection with surgery for
navigation, resection of bone, assessment and other purposes.
[0064] FIGS. 2-22 are various views associated with High Tibial
Osteotomy surgery processes according to one particular embodiment
and version of the present invention being carried out with the
FluoroNav system referred to above. FIG. 2 shows a human knee in
the surgical field, as well as the corresponding femur and tibia,
to which fiducials 14 have been rigidly attached in accordance with
this embodiment of the invention. Attachment of fiducials 14
preferably is accomplished using structure that withstands
vibration of surgical saws and other phenomenon which occur during
surgery without allowing any substantial movement of fiducial 14
relative to body part being tracked by the system.
[0065] FIG. 3 shows fluoroscopy images being obtained of the body
parts with fiducials 14 attached. The fiducial 14 on the
fluoroscopy head in this embodiment is a cylindrically shaped cage
which contains LEDs or "active" emitters for tracking by the
sensors 16. Fiducials 14 attached to tibia 12 and femur 10 can also
be seen. The fiducial 14 attached to the femur 10 uses LEDs instead
of reflective spheres and is thus active, fed power by the wire
seen extending into the bottom of the image.
[0066] FIGS. 4-10 are fluoroscopic images shown on monitor 24
obtained with position and/or orientation information received by,
noted and stored within computer 18. FIG. 4 is an open field with
no body part image, but which shows the optical indicia which may
be used to normalize the image obtained using a spherical
fluoroscopy wave front with the substantially flat surface of the
monitor 24. FIG. 5 shows an image of the femur 10 head. This image
is taken in order to allow the surgeon to designate the center of
rotation of the femoral head for purposes of establishing the
mechanical axis and other relevant constructs relating to of the
femur according to which the wedge of bone will ultimately be
resected. Such center of rotation can be established by
articulating the femur within the acetabulum or a prosthesis to
capture a number of samples of position and orientation information
and thus in turn to allow the computer to calculate the average
center of rotation. The center of rotation can be established by
using the probe and designating a number of points on the femoral
head and thus allowing the computer to calculate the geometrical
center or a center which corresponds to the geometry of points
collected. Additionally, graphical representations such as
controllably sized circles displayed on the monitor can be fitted
by the surgeon to the shape of the femoral head on planar images
using tactile input on screen to designate the centers according to
that graphic, such as are represented by the computer as
intersection of axes of the circles. Other techniques for
determining, calculating or establishing points or constructs in
space, whether or not corresponding to bone structure, can be used
in accordance with the present invention.
[0067] FIG. 5 shows a fluoroscopic image of the femoral head while
FIG. 6 shows an anterior/posterior view of the knee which can be
used to designate landmarks and establish axes or constructs such
as the mechanical axis or other rotational axes. FIG. 7 shows the
distal end of the tibia and FIG. 8 shows a lateral view of the
knee. FIG. 9 shows another lateral view of the knee while FIG. 10
shows a lateral view of the distal end of the tibia.
[0068] Registration of Surgically Related Items
[0069] FIG. 11 shows designation or registration of items 22 which
will be used in surgery. Registration simply means, however it is
accomplished, ensuring that the computer knows which body part,
item or construct corresponds to which fiducial or fiducials, and
how the position and orientation of the body part, item or
construct is related to the position and orientation of its
corresponding fiducial or a fiducial attached to an impactor or
other other component which is in turn attached to an item. Such
registration or designation can be done before or after registering
bone or body parts as discussed with respect to FIGS. 4-10. FIG. 11
shows a technician designating with probe 26 an item 22 such as an
instrument component to which fiducial 14 is attached. The sensor
16 "sees" the position and orientation of the fiducial 14 attached
to the item 22 and also the position and orientation of the
fiducial 14 attached to the probe 26 whose tip is touching a
landmark on the item 22. The technician designates onscreen or
otherwise the identification of the item 22 and then activates the
foot pedal or otherwise instructs the computer to correlate the
data corresponding to such identification, such as data needed to
represent a particular cutting jig, with the particularly shaped
fiducial 14 attached to the cutting jig. The computer has then
stored identification, position and orientation information
relating to the fiducial for item 22 correlated with the data such
as configuration and shape data for the item 22 so that upon
registration, when sensor 16 tracks the item 22 fiducial 14 in the
infrared field, monitor 24 can show the item 22 moving and turning,
and properly positioned and oriented relative to the body part
which is also being tracked.
[0070] Registration of Anatomy and Constructs
[0071] Similarly, the mechanical axis and other axes or constructs
of body parts 10 and 12 can also be "registered" for tracking by
the system. Again, the system has employed a fluoroscope to obtain
images of the femoral head, knee and ankle of the sort shown in
FIGS. 4-10. The system correlates such images with the position and
orientation of the C-arm and the patient anatomy in real time as
discussed above with the use of fiducials 14 placed on the body
parts before image acquisition and which remain in position during
the surgical procedure. Using these images and/or the probe, the
surgeon can select and register in the computer 18 the center of
the femoral head and ankle in orthogonal views, usually
anterior/posterior and lateral, on a touch screen. The surgeon uses
the probe to select any desired anatomical landmarks or references
at the operative site of the knee or on the skin or surgical
draping over the skin, as on the ankle. These points are registered
in three dimensional space by the system and are tracked relative
to the fiducials on the patient anatomy which are preferably placed
intraoperatively. FIG. 12 shows the surgeon using probe 26 to
designate or register landmarks on the condylar portion of femur 10
using probe 26 in order to feed to the computer 18 the position of
one point needed to determine, store, and display the epicondylar
axis. (See FIG. 14 which shows the epicondylar axis and the
anterior-posterior plane and for lateral plane.) Although
registering points using actual bone structure such as in FIG. 12
is one preferred way to establish the axis, a cloud of points
approach by which the probe 26 is used to designate multiple points
on the surface of the bone structure can be employed, as can moving
the body part and tracking movement to establish a center of
rotation as discussed above. Once the center of rotation for the
femoral head and the condylar component have been registered, the
computer is able to calculate, store, and render, and otherwise use
data for, the mechanical axis of the femur 10.
[0072] FIG. 13 shows the onscreen images being obtained when the
surgeon registers certain points on the bone surface using the
probe 26 in order to establish the femoral mechanical axis. The
tibial mechanical axis is then established by designating points to
determine the centers of the proximal and distal ends of the tibia
so that the mechanical axis can be calculated, stored, and
subsequently used by the computer 18. FIG. 14 shows designated
points for determining the epicondylar axis, both in the
anterior/posterior and lateral planes while FIG. 15 shows such
determination of the anterior-posterior axis as rendered onscreen.
The posterior condylar axis is also determined by designating
points or as otherwise desired, as rendered on the computer
generated geometric images overlain or displayed in combination
with the fluoroscopic images, all of which are keyed to fiducials
14 being tracked by sensors 16.
[0073] FIG. 16 is an onscreen image showing the anterior-posterior
axis, epicondylar axis and posterior condylar axis from points
which have been designated as described above. These constructs are
generated by the computer 18 and presented on monitor 24 in
combination with the fluoroscopic images of the femur 10, correctly
positioned and oriented relative thereto as tracked by the system.
In the fluoroscopic/computer generated image combination shown at
left bottom of FIG. 16, a "sawbones" knee as shown in certain
drawings above which contains radio opaque materials is represented
fluoroscopically and tracked using sensor 16 while the computer
generates and displays the mechanical axis of the femur 10 which
runs generally horizontally. The epicondylar axis runs generally
vertically, and the anterior/posterior axis runs generally
diagonally. The image at bottom right shows similar information in
a lateral view. Here, the anterior-posterior axis runs generally
horizontally while the epicondylar axis runs generally diagonally,
and the mechanical axis generally vertically.
[0074] FIG. 16, as is the case with a number of screen
presentations generated and presented by the system of FIGS. 4-22,
also shows at center a list of landmarks to be registered in order
to generate relevant axes and constructs useful in navigation,
positioning and assessment during surgery. Textural cues may also
be presented which suggest to the surgeon next steps in the process
of registering landmarks and establishing relevant axes. Such
instructions may be generated as the computer 18 tracks, from one
step to the next, registration of items 22 and bone locations as
well as other measures being taken by the surgeon during the
surgical operation.
[0075] FIG. 17 shows mechanical, lateral, anterior-posterior axes
for the tibia according to points are registered by the
surgeon.
[0076] Wedge Resection
[0077] After the mechanical axis and other rotation axes and
constructs relating to the femur and tibia are established,
instrumentation can be properly oriented to resect or modify bone
in order to properly resect a bone wedge according to the
embodiment of the invention shown in FIGS. 4-22. Instrumentation
such as, for instance, cutting jigs, to which fiducials 14 are
mounted, can be employed. The system can then track instrumentation
as the surgeon manipulates it for optimum positioning. In other
words, the surgeon can "navigate" the instrumentation for optimum
positioning using the system and the monitor. In this manner,
instrumentation may be positioned according to the system of this
embodiment in order to align the ostetomies to the mechanical and
rotational axes or reference axes. The touchscreen 24 can then also
display the instrument such as the cutting jig and/or the pivot pin
relative to the cutting jig during this process, in order, among
other things, properly to resect a wedge of bone. As the cutting
jig moves, the varus/valgus, flexion/extension and
internal/external rotation of the relative cutting jig position can
be calculated and shown with respect to the referenced axes; in the
preferred embodiment, this can be done at a rate of six cycles per
second or faster. The cutting jig position is then fixed in the
computer and physically and the bone wedge resections are made.
[0078] FIG. 18 shows the placement of a pivot pin to which a
fiducial is attached via a drill sleeve. The system navigates the
placement of a pivot pin at a level of 1 cm from the medial cortex
of the tibia and 1 cm below the level of the tibial plateau. The
pin is placed perpendicular to the frontal plane and parallel to
the sagittal plane. The pivot pin acts as an intersection point for
two resection planes of the wedge.
[0079] FIG. 19 shows tibial cutting jigs. The system navigates two
cutting jigs on an assembly that slides over the pivot pin. The
proximal jig is aligned parallel to the tibial plateau and fixed to
the tibia, as shown in FIG. 20. The distal jig is then placed
radially about the pivot pin.
[0080] FIG. 21 also shows other information relevant to the surgeon
such as the name of the component being overlain on the tibial
image, suggestions or instructions at the lower left, and angle of
the rod in varus/valgus and extension relative to the axes. Any or
all of this information can be used to navigate and position the
cutting jig relative to the tibia.
[0081] Navigation, Placement and Assessment of Angle
[0082] Once the distal jig is placed radially about the pivot pin,
the jig is adjusted radially to the desired angle calculated by the
system based on desired correction algorithms and reference axes.
The distal jig is fixed to the tibia and the bone wedge is
resected. After removal of the wedge, either the opening is reduced
and plated or stapled for a closed wedge procedure, as shown in
FIG. 22, or it is braced open with a plate for an open wedge
procedure. The open wedge is then grafted to fill the void.
[0083] During the wedge resection process, instrument positioning
process or at any other desired point in surgical or other
operations according to the present invention, the system can
transition or segue from tracking a component according to a first
fiducial to tracking the component according to a second fiducial.
Thus, the pivot pin can be mounted on an drill sleeve to which a
fiducial 14 is attached. The pivot pin is installed and positioned
using the drill sleeve. The computer 18 "knows" the position and
orientation of the pin relative to the fiducial on the drill sleeve
(such as by prior registration of the component attached to the
drill sleeve) so that it can generate and display the image of the
pivot pin on screen 24 overlaid on the fluoroscopic image of the
tibia. At any desired point in time, before, during or after the
pivot pin is properly placed in the tibia to align with mechanical
axis and according to proper orientation relative to other axes,
the system can be instructed by foot pedal or otherwise to begin
tracking the position of the pivot pin using the fiducial attached
to the tibia rather than the one attached to the drill sleeve.
According to the preferred embodiment, the sensor 16 "sees" at this
point in time both the fiducials on the drill sleeve and the tibia
12 so that it already "knows" the position and orientation of the
pivot pin relative to the fiducial on the drill sleeve and is thus
able to calculate and store for later use the position and
orientation of the pivot pin relative to the tibia 12 fiducial.
Once this "handoff" happens, the drill sleeve can be removed and
the pivot pin tracked with the tibia fiducial 14 as part of or
moving in concert with the tibia 12. Similar handoff procedures may
be used in any other instance as desired in accordance with the
present invention.
[0084] At the end of the case, all alignment information can be
saved for the patient file. This is of great assistance to the
surgeon due to the fact that the outcome of implant positioning can
be seen before any resectioning has been done on the bone. The
system is also capable of tracking the patella and resulting
placement of cutting guides and the patellar trial position. The
system then tracks alignment of the patella with the patellar
femoral groove and will give feedback on issues, such as, patellar
tilt.
[0085] The tracking and image information provided by systems and
processes according to the present invention facilitate telemedical
techniques, because they provide useful images for distribution to
distant geographic locations where expert surgical or medical
specialists may collaborate during surgery. Thus, systems and
processes according to the present invention can be used in
connection with computing functionality 18 which is networked or
otherwise in communication with computing functionality in other
locations, whether by PSTN, information exchange infrastructures
such as packet switched networks including the Internet, or as
otherwise desire. Such remote imaging may occur on computers,
wireless devices, videoconferencing devices or in any other mode or
on any other platform which is now or may in the future be capable
of rending images or parts of them produced in accordance with the
present invention. Parallel communication links such as switched or
unswitched telephone call connections may also accompany or form
part of such telemedical techniques. Distant databases such as
online catalogs of implant suppliers or prosthetics buyers or
distributors may form part of or be networked with functionality 18
to give the surgeon in real time access to additional options for
implants which could be procured and used during the surgical
operation.
* * * * *