U.S. patent application number 14/634363 was filed with the patent office on 2015-09-03 for system and methods for positioning bone cut guide.
The applicant listed for this patent is Branislav Jaramaz, Constantinos Nikou. Invention is credited to Branislav Jaramaz, Constantinos Nikou.
Application Number | 20150245878 14/634363 |
Document ID | / |
Family ID | 54006212 |
Filed Date | 2015-09-03 |
United States Patent
Application |
20150245878 |
Kind Code |
A1 |
Jaramaz; Branislav ; et
al. |
September 3, 2015 |
SYSTEM AND METHODS FOR POSITIONING BONE CUT GUIDE
Abstract
Systems and methods for positioning a cut guide using
navigation-based techniques are discussed. For example, a system
for use in an orthopedic surgery on a target bone can comprise a
cut guide adjustably positionable onto the target bone via two or
more coupling receptacles created on the target bone. The coupling
receptacles can include one or more guide members and a plurality
of landing members. The system also includes an input interface
that can receive a target bone representation, and a model receiver
module that can receive a generic post-coupling bone model. The
target bone representation can include a data set representing two
or more landing sites of the target bone, and the generic
post-coupling bone model can include a data set representing a bone
having two or more coupling receptacles each sized, shaped or
otherwise configured to receive and secure the respective coupling
feature of the landing members. The system can include a
navigation-based guide coupling preparation system that can
generate a plan for positioning the cut guide onto or conforming to
the target bone. The system can further include a display module
that provides presentations of the coupling between the target bone
and the cut guide.
Inventors: |
Jaramaz; Branislav;
(Pittsburgh, PA) ; Nikou; Constantinos;
(Pittsburgh, PA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Jaramaz; Branislav
Nikou; Constantinos |
Pittsburgh
Pittsburgh |
PA
PA |
US
US |
|
|
Family ID: |
54006212 |
Appl. No.: |
14/634363 |
Filed: |
February 27, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61946428 |
Feb 28, 2014 |
|
|
|
Current U.S.
Class: |
606/87 |
Current CPC
Class: |
A61B 2034/108 20160201;
G16H 40/63 20180101; A61B 17/15 20130101; A61B 2034/107 20160201;
G16H 50/50 20180101; A61B 34/20 20160201; A61B 17/155 20130101;
A61B 17/16 20130101; A61B 2034/105 20160201; A61B 17/17 20130101;
G16H 40/40 20180101; G16H 20/40 20180101; A61B 2034/2074 20160201;
A61B 34/10 20160201 |
International
Class: |
A61B 19/00 20060101
A61B019/00; A61B 17/17 20060101 A61B017/17 |
Claims
1. An orthopedic surgical device for use in operating on a target
bone, comprising: a cut guide configured to be adjustably
positioned onto or otherwise conform to the target bone, the cut
guide comprising: a guide body forming the cut guide, the guide
body including one or more guide members each sized, shaped or
otherwise configured to constrain and guide a cutting tool along a
respective cutting trajectory; and a plurality of landing members,
each of the plurality of landing members including a respective
coupling feature configured to removably couple to a landing site
of the target bone, wherein the one or more guide members are
configured to guide the cutting tool to cut the target bone along
the respective cutting trajectory when the plurality of landing
members are coupled to the landing site of the target bone.
2. The device of claim 1, wherein the coupling feature of each of
the landing members includes a protruding portion configured to be
end-user engaged into a respective coupling receptacle on the
landing site of the target bone, the coupling receptacle including
a recessed portion sized, shaped or otherwise configured to receive
and secure the protruding portion of the respective coupling
feature of each of the plurality of landing members.
3. The device of claim 1, wherein the plurality of landing members
are configured to be fixed onto an exterior of the guide body.
4. The device of claim 1, wherein at least one of the plurality of
landing members is reconfigurable relative to the guide body, the
at least one reconfigurable landing member connected to the guide
body and having at least one degree of freedom of movement relative
to the guide body.
5. The device of claim 4, wherein the at least one reconfigurable
landing member is configured to adjustably lock onto the guide body
when the at least one reconfigurable landing member is positioned
at the landing site and attached to the target bone, or when the at
least one reconfigurable landing member is not used for attaching
to the target bone.
6. The device of claim 1, wherein the protruding portions of the
landing members do not cross the cutting trajectories associated
with the one or more guide members.
7. A system for use in an orthopedic surgery on a target bone,
comprising: a cut guide adjustably positionable onto the target
bone via two or more coupling receptacles created on the target
bone, the cut guide comprising: a guide body forming the cut guide,
the guide body including one or more guide members each sized,
shaped or otherwise configured to guide a cutting tool with respect
to a respective cutting trajectory; and a plurality of landing
members, each of the plurality of landing members including a
respective coupling feature; an input interface configured to
receive a target bone representation including a data set
representing two or more landing sites of the target bone
(X.sub.pre-coupling); a model receiver module configured to receive
a generic post-coupling bone model (M.sub.coupling) including a
data set representing a bone having the two or more coupling
receptacles each sized, shaped or otherwise configured to receive
and secure the respective coupling feature of each of the plurality
of landing members; a navigation-based guide coupling preparation
system, including a cut guide positioning planning module
configured to generate a plan for positioning the cut guide onto or
conforming to the target bone, the cut guide positioning planning
module including: a first registration module configured to
register M.sub.coupling to X.sub.pre-coupling and create a
registered generic post-coupling bone model; and a positioning plan
formation module configured, using the registered generic
post-coupling bone model, to respectively determine the two or more
landing sites of the target bone for creating the two or more
coupling receptacles and geometric or morphological descriptors of
the two or more coupling receptacles; and a display module
configured to provide one or more of: the data set representing the
two or more landing sites of the target bone (X.sub.pre-coupling);
the generic post-coupling bone model (M.sub.coupling); the landing
site of the target bone; and the size, shape, and geometric or
morphological descriptors of the two or more coupling receptacles
on the target bone.
8. The system of claim 7, wherein the navigation-based guide
coupling preparation system further includes a temporary coupling
receptacle preparation tool used for producing the two or more
coupling receptacles on the landing site of the target bone,
wherein each of the two or more coupling receptacles includes a
recessed portion sized, shaped or otherwise configured to receive
and secure the protruding portion of the respective coupling
feature of each of the plurality of landing member, and wherein the
temporary coupling receptacle preparation tool is configured to be
capable of creating the recessed portion on the target bone.
9. The system of claim 7, wherein: the input interface configured
to receive a peri-operative target bone representation including a
data set representing the size, shape, volume, or other geometric
or morphological descriptors of the coupling receptacle of the
target bone (X.sub.peri-coupling); the positioning plan formation
module is further configured to (1) compute a similarity metric
between the coupling receptacle on the registered generic
post-coupling bone model and the corresponding perioperative
coupling receptacle on the perioperative target bone representation
X.sub.peri-coupling and (2) to generate an indication of completion
of the coupling receptacle preparation in response to the
similarity metric meeting a specified criterion; and the display
module configured to provide the peri-operative target bone
representation X.sub.peri-coupling, the similarity metric, and the
indication of the completion of the coupling receptacle
preparation.
10. The system of claim 7, further comprising a navigation-based
surgical system including a surgical planning module configured to
generate a surgical plan for altering a portion of the target bone
when the cut guide is securely positioned onto or otherwise
conforms to the target bone, wherein: the input interface is
further configured to receive a target bone representation
including a data set representing a portion of the target bone to
be altered (X.sub.pre-op); the model receiver module is further
configured to receive a generic post-operative bone model
(M.sub.post-op including a data set representing a post-operative
bone, and wherein the surgical planning module includes: a second
registration module configured to register M.sub.post-op to
X.sub.pre-op and create a registered generic post-operative bone
model; and a surgical plan formation module configured, using the
registered generic post-operative bone model, to select one or more
guide members, and to schedule a sequence of bone cuts along the
cutting trajectories associated with the selected one or more guide
members; and the display module is further configured to provide
one or more of: the data set representing the portion of the target
bone to be altered (X.sub.pre-op); the generic post-operative bone
model (M.sub.post-op); the selected guide members on the cut guide;
and the scheduled sequence of bone cuts along the cutting
trajectories.
11. The system of claim 7, wherein: the positioning plan formation
module is further configured to determine a degree of coupling
between the coupling feature and the respective coupling receptacle
using a measurement of position of the coupling feature relative to
the respective coupling receptacle; and the display module is
configured to provide a representation of a degree of coupling
between the coupling feature and the respective coupling
receptacle.
12. A method for operating a system for use in an orthopedic
surgery on a bone, the method comprising: providing a cut guide
configured to be adjustably positionable onto or otherwise to
conform to the target bone, the cut guide including (1) a guide
body having one or more guide members sized, shaped or otherwise
configured to guide a cutting tool along a respective cutting plan,
and (2) a plurality of landing members, each of the plurality of
landing members including a respective coupling feature configured
to removably couple to the target bone via two or more coupling
receptacles created on the target bone; receiving a target bone
representation including a data set representing two or more
landing sites of the target bone (X.sub.pre-coupling); receiving a
generic post-coupling bone model (M.sub.coupling) including a data
set representing a bone having the two or more coupling
receptacles; and generating a cut guide positioning plan for
positioning the cut guide onto or conforming to the target
bone.
13. The method of claim 12, wherein generating the cut guide
positioning plan includes: registering M.sub.coupling to
X.sub.pre-coupling and creating a registered generic post-coupling
bone model; and determining, using the registered generic
post-coupling bone model, the two or more landing sites of the
target bone for creating the two or more coupling receptacles and
geometric or morphological descriptors of the two or more coupling
receptacles.
14. The method of claim 13, wherein selecting the two or more
landing sites includes determining locations of the two or more
landing sites on the target bone using information including size
and shape of the coupling features of the plurality of landing
members and the cutting trajectories relative to the target
bone.
15. The method of claim 12, further comprising: receiving a target
bone representation including a data set representing a portion of
the target bone to be altered (X.sub.pre-op ); receiving a generic
post-operative bone model (M.sub.post-op) including a data set
representing a post-operative bone having an anatomical origin
comparable to the target bone; generating a surgical plan for
altering a portion of the target bone when the cut guide is
securely positioned onto or otherwise conforms to the target bone;
and altering the target bone in accordance with the surgical plan
using the cutting tool and the cut guide.
16. The method of claim 15, wherein generating the surgical plan
includes: registering M.sub.post-op to X.sub.pre-op and creating a
registered generic post-operative bone model; selecting one or more
guide members using the registered generic post-operative bone
model; and scheduling a sequence of bone cuts along the cutting
trajectories associated with the selected one or more guide members
when the coupling features of the cut guide are coupled to the
coupling receptacles of the target bone.
17. The method of claim 15, wherein receiving X.sub.pre-op includes
receiving a mathematical descriptive model or a two-dimensional or
three-dimensional graphical model of the target bone, and wherein
receiving M.sub.post-op includes receiving a mathematical
descriptive model or a two-dimensional or three-dimensional
graphical model of the post-operative bone.
18. The method of claim 12, further comprising: producing,
respectively at the two or more landing sites, the two or more
coupling receptacles sized, shaped or otherwise configured to
receive and secure the respective coupling feature of each of the
plurality of landing members; and attaching the cut guide to the
landing site of the target bone by respectively engaging the
coupling features with the coupling receptacles, wherein producing
a coupling receptacle includes producing a recessed portion at the
landing site of the target bone, the recessed portion sized, shaped
or otherwise configured to receive and secure the protruding
portion of the respective coupling feature of each of the plurality
of landing members.
19. The method of claim 18, wherein producing the recessed portion
includes: generating a recess creation plan including geometric or
morphological descriptors of the recessed portion; and creating the
recessed portion using a surgical tool in accordance with the
recess creation plan.
20. A machine-readable storage medium including instructions that,
when executed by a machine, cause the machine to: receive a target
bone representation including a data set representing two or more
landing sites of the target bone (X.sub.pre-coupling); select a cut
guide configured to be adjustably positionable onto or otherwise to
conform to the target bone, the cut guide including (1) a guide
body having one or more guide members sized, shaped or otherwise
configured to guide a cutting tool along a respective cutting plan,
and (2) a plurality of landing members, each of the plurality of
landing members including a respective coupling feature configured
to removably couple to the target bone via two or more coupling
receptacles created on the target bone; receive a generic
post-coupling bone model (M.sub.coupling) including a data set
representing a bone having the two or more coupling receptacles;
and generate a cut guide positioning plan for positioning the cut
guide onto or conforming to the target bone.
21. The machine-readable storage medium of claim 20, wherein the
instruction causing the machine to generate the cut guide
positioning plan includes causing the machine to register
M.sub.coupling to X.sub.pre-coupling and create a registered
generic post-coupling bone model, and to determine, using the
registered generic post-coupling bone model, the two or more
landing sites of the target bone for creating the two or more
coupling receptacles and geometric or morphological descriptors of
the two or more coupling receptacles.
22. The machine-readable storage medium of claim 21, wherein the
instruction causing the machine to select the two or more landing
sites includes causing the machine to determine locations of the
two or more landing sites on the target bone using information
including size and shape of the coupling features of the plurality
of landing members and the cutting trajectories relative to the
target bone.
23. The machine-readable storage medium of claim 20, further
comprising instructions that cause the machine to: receive a target
bone representation including a data set representing a portion of
the target bone to be altered (X.sub.pre-op); receive a generic
post-operative bone model (M.sub.post-op) including a data set
representing a post-operative bone having an anatomical origin
comparable to the target bone; generate a surgical plan for
altering a portion of the target bone when the cut guide is
securely positioned onto or otherwise conforms to the target bone;
and alter the target bone in accordance with the surgical plan
using the cutting tool and the cut guide.
24. The machine-readable storage medium of claim 23, wherein the
instruction causing the machine to generate the surgical plan
includes causing the machine to: register M.sub.post-op to
X.sub.pre-op and create a registered generic post-operative bone
model; select one or more guide members using the registered
generic post-operative bone model; and schedule a sequence of bone
cuts along the cutting trajectories associated with the selected
one or more guide members when the coupling features of the cut
guide are coupled to the coupling receptacles of the target
bone.
25. The machine-readable storage medium of claim 23, wherein the
instruction causing the machine to receive X.sub.pre-op includes
causing the machine to receive a mathematical descriptive model or
a two-dimensional or three-dimensional graphical model of the
target bone, and wherein the instruction causing the machine to
receive M.sub.post-op includes causing the machine to receive a
mathematical descriptive model or a two-dimensional or
three-dimensional graphical model of the post-operative bone.
26. The machine-readable storage medium of claim 20, further
comprising instructions that cause the machine to: produce,
respectively at the two or more landing sites, the two or more
coupling receptacles sized, shaped or otherwise configured to
receive and secure the respective coupling feature of each of the
plurality of landing members; and attach the cut guide to the
landing site of the target bone by respectively engaging the
coupling features with the coupling receptacles, wherein the
instruction causing the machine to produce a coupling receptacle
includes causing the machine to produce a recessed portion at the
landing site of the target bone, the recessed portion sized, shaped
or otherwise configured to receive and secure the protruding
portion of the respective coupling feature of each of the plurality
of landing members.
27. The machine-readable storage medium of claim 26, wherein the
instruction causing the machine to produce the recessed portion
includes causing the machine to generate a recess creation plan
including geometric or morphological descriptors of the recessed
portion, and to create the recessed portion using a surgical tool
in accordance with the recess creation plan.
Description
CLAIM OF PRIORITY
[0001] This patent application claims the benefit of priority of
U.S. Provisional Patent Application Ser. No. 61/946,428, titled
"System and Methods for Positioning Bone Cut Guide," filed on Feb.
28, 2014, which is hereby incorporated by reference herein in its
entirety.
TECHNICAL FIELD
[0002] This document relates generally to computer-aided orthopedic
surgery, and more specifically to systems and methods for
positioning a cut guide to a target bone and for altering the
target bone using the cut guide.
BACKGROUND
[0003] The use of computers, robotics, and imaging to aid
orthopedic surgery is well known in the art. There has been a great
deal of study and development of computer-aided navigation and
robotics systems used to guide surgical procedures. For example, a
precision freehand sculptor (PFS) employs a robotic surgery system
to assist the surgeon in accurately cutting a bone into a desired
shape. In interventions such as total hip replacement,
computer-aided surgery techniques have been used to improve the
accuracy, reliability of the surgery. Orthopedic surgery guided by
images has also been found useful in preplanning and guiding the
correct anatomical position of displaced bone fragments in
fractures, allowing a good fixation by osteosynthesis.
[0004] A cut guide can be used in an orthopedic surgery to assist a
surgeon in cutting or modifying some portions of a target bone. For
example, in joint replacement surgeries such as total hip
replacement (THR) or total knee replacement (TKR), a cut guide can
be temporarily attached to the target bone such as a femur or a
tibia. An orthopedic surgical cutting tool can be used together
with the cut guide to allow the surgeon to selectively cut portions
of the ends of the target bone and replaced with endoprosthetic
implants. Positioning a cut guide for use in preparing the target
bone can be a time consuming and complicated process, which is
critical to positive outcomes for the patient.
SUMMARY
[0005] Quick and reliable positioning of a cut guide can be crucial
to the outcome of orthopedic surgeries such as prosthesis
implantation. In joint replacement surgeries, for example, portions
of the articulation tissues of a target bone, such as acetabulum, a
femur, or a tibia, need to resected and altered to allow an implant
to be securely positioned onto the target bone. A cut guide
positioned on the target bone can be used to guide a cutting saw to
resect the target bone to a desired shape. Proper positioning of
the cut guide on the bone can improve the accuracy of the bone
resection and reduce procedure time. On the contrary, improper
positioning of the cut guide can result in undesirable cutting
surfaces on the target bone, which can further cause impingement,
increased rates of implant dislocation, wear and failure of the
implant, among many other complications. The procedure time can
also be lengthened due to the requirement of modifying the
undesirable cutting shape.
[0006] Positioning of cut guide onto a target bone usually requires
a surgeon to mentally map and compare the shape, orientation, and
relative positions of the implant and the target bones. Mechanical
jigs that align to general specifications, rather than aligning to
parameters optimal for the patient. This method can be difficult to
operate and may suffer from lack of reliability and certainty.
Determining and visualizing the correct positions and orientations
of the prosthesis with respect to the target bone can be
practically difficult. Computer-aided tools can be used to assist
the surgeon in positioning the cut guide relative to the bone.
However, often the computer-assistance is limited to intraoperative
navigation of traditional cutting jigs. The designs of these jigs,
the tools to align them, and the implants that they support are all
compromises meant to serve a general population. Other systems uses
computers to analyze patient specific images used to design
patient-conforming instrumentation and sometimes even implants
specific to the patient. However, these images either use ionizing
radiation (e.g. computed tomography images) or are prone to error
or gaps in tissue differentiation (e.g. magnetic resonance
imaging).Therefore, the present inventors have recognized that
there remains a considerable need for systems and methods that can
assist the surgeon in reliably positioning a cut guide onto the
target bone with improved accuracy, speed, and consistency, while
still allowing for some customization.
[0007] Various embodiments described herein can help improve the
efficacy and the reliability in positioning a cut guide onto a
target bone to alter a portion of the target bone. For example, an
orthopedic surgical device can comprise a cut guide that is
configured to be adjustably positioned onto or otherwise conform to
the target bone. The cut guide includes a plurality of landing
members. Each landing member includes a coupling feature that can
removably couple to a landing site of the target bone. The cut
guide also includes one or more guide members on the guide body.
Each guide member can be sized, shaped or configured to constrain
and guide a cutting tool along a respective cutting trajectory. The
guide member can guide the cutting tool to cut the target bone
along the respective cutting trajectory when the landing members
are coupled to the landing site of the target bone. In an example,
the guide member can include guide slots or surfaces for guiding a
surgical saw in making cuts on a target bone. Multiple cut guides
with the same cutting trajectories can be made available that have
different landing member placements, in order to accommodate
different sizes and shapes of bones.
[0008] A system embodiment for use in an orthopedic surgery on a
target bone can comprise a cut guide adjustably positionable onto a
target bone via two or more coupling receptacles created on the
target bone. The cut guide can include one or more guide members
and a plurality of landing members. The system also includes an
input interface that can receive a target bone representation, and
a model receiver module that can receive a generic post-coupling
bone model. The target bone representation can include a data set
representing two or more landing sites of the target bone, and the
generic post-coupling bone model can include a data set
representing a bone having two or more coupling receptacles each
sized, shaped or otherwise configured to receive and secure the
respective coupling feature of the landing members. The system can
include a navigation-based guide coupling preparation system that
can generate a plan for positioning the cut guide onto or
conforming to the target bone. The system can further include a
display module that provides presentations of the coupling between
the target bone and the cut guide.
[0009] A method embodiment for operating a system for use in an
orthopedic surgery on a bone can comprise the operations of
providing a cut guide that is adjustably positionable onto or
conformed to the target bone, and receiving a target bone
representation and a generic post-coupling bone model. The target
bone representation can include a data set representing two or more
landing sites of the target bone, and the generic post-coupling
bone model can include a data set representing a bone having two or
more coupling receptacles configured to receive and secure the
respective coupling feature of the landing members. The method can
comprise the operations of generating a cut guide positioning plan
for positioning the cut guide onto or conforming to the target
bone, producing at the landing sites coupling receptacles that are
sized, shaped or configured to receive and secure the respective
coupling features of the landing members, and attaching the cut
guide to the landing site of the target bone by engaging the
coupling features with the coupling receptacles.
[0010] This Summary is an overview of some of the teachings of the
present application and not intended to be an exclusive or
exhaustive treatment of the present subject matter. Further details
about the present subject matter are found in the detailed
description and appended claims. Other aspects of the invention
will be apparent to persons skilled in the art upon reading and
understanding the following detailed description and viewing the
drawings that form a part thereof, each of which are not to be
taken in a limiting sense. The scope of the present invention is
defined by the appended claims and their legal equivalents.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Various embodiments are illustrated by way of example in the
figures of the accompanying drawings. Such embodiments are
demonstrative and not intended to be exhaustive or exclusive
embodiments of the present subject matter.
[0012] FIGS. 1A-D illustrate an example of an orthopedic surgical
device for use in operating on a target bone.
[0013] FIGS. 2A-B are block diagrams that illustrate an example of
a cut guide positioning system.
[0014] FIGS. 3A-B illustrate an example of preparing coupling
receptacles on a target bone.
[0015] FIGS. 4A-B are block diagrams that illustrate an example of
an orthopedic surgical system.
[0016] FIGS. 5A-C illustrate an example of selecting a set of guide
members and generating an ordered sequence of bone cuts on a target
bone.
[0017] FIG. 6 is a flowchart that illustrates an example of a
method for positioning a cut guide onto a target bone.
[0018] FIG. 7 is a flowchart that illustrates an example of a
method for producing coupling receptacles on the target bone.
[0019] FIG. 8 is a flowchart that illustrates an example of a
method for resecting a portion of a target bone using a cut
guide.
[0020] FIG. 9 is a block diagram that illustrates an example of a
computer system within which instructions for causing the computer
system to perform bone cut positioning may be executed.
DETAILED DESCRIPTION
[0021] Disclosed herein are systems, devices and methods for
positioning a cut guide onto a target bone using a plurality of
coupling receptacles produced with the assistance of a
navigation-based guide coupling preparation system. Various
embodiments described herein can help improve the efficacy and the
reliability in osteoplasty planning, such as resecting portions of
bone surface for cut guide positioning. The methods and devices
described herein can also be applicable to planning surgery of
pathological bones under various other conditions.
[0022] FIGS. 1A-D illustrate an example of an orthopedic surgical
device for use in operating on a target bone 300. The orthopedic
surgical device comprises a cut guide 100, illustrated in FIG. 1B,
configured to be adjustably positioned onto or otherwise conform to
the target bone 300 as illustrated in FIG. 1A. The cut guide 100
includes a guide body 110 forming the cut guide 100, and a
plurality of landing members such as 130A-B. The guide body 110
forms the supporting structure of the cut guide 100, and can be
made of metal, alloy, polymer, or other rigid dimensionally stable
materials.
[0023] The guide body 110 includes one or more guide members
120A-D. Each guide member can be sized, shaped or otherwise
configured to constrain and guide a cutting tool (not shown) along
a respective cutting trajectory determined by the guide member. The
guide members 120A-D can have slotted structures sized to securely
receive and constrain the cutting tool, and allow the cutting tool
to move freely within the respective slotted structure. The guide
members 120A-D can have openings on an exterior of the guide body
110. The openings can be sized to facilitate placement of the
cutting tool into one or more of the guide members 120A-D, and
connection between a portion of the cutting tool and an external
driving device such as a robotic arm for manipulating the cutting
tool within the guide members.
[0024] Each guide member (such as a slot) has a pre-determined
orientation that defines the cutting trajectory. As illustrated in
FIG. 1B, the guide member 120A is horizontally oriented, the guide
member 120B vertically oriented, and the guide members 120C and
120D each oriented at specified tilt angles. The orientations of
the guide members 120A-D can be different from each other, thereby
allowing bone cuts from different angles. In some examples, at
least two guide members have the same orientation. This provides a
system end-user with flexibility in selecting desired amount of
bone cut along a particular cutting plane. The number of guide
members on the guide body 110 can be more than what is needed for
resecting a particular target bone. Such redundancy of guide
members can make the cut guide 100 a generic tool for modifying
target bones that have different desired post-operative sizes or
shapes.
[0025] Each of the landing members 130A-B on the cut guide 100 can
include a respective coupling feature. The coupling features can be
configured to removably couple to the target bone 300 at two or
more landing sites on the target bone 300. The landing sites define
desired locations on the target bone onto which the cut guide can
be securely positioned.
[0026] As illustrated in FIG. 1B, on the cut guide 100, the
coupling features can further include protruding portions such as
131A-B extended from the landing members 130A-B. The protruding
portions 131A-B can have a shape of a cylinder, a cube, a
rectangular prism, a triangular prism, a pyramid, a cone, or other
three-dimensional structures. As illustrated in FIG. 1A, on the
target bone 300, two or more coupling receptacles such as 331A-B
can be produced at the landing sites with assistance of a
navigation-based guide coupling preparation system. The coupling
receptacles 331A-B on the target bone 300 each include a recessed
portion that is sized, shaped or otherwise configured to receive
and secure a respective protruding portion, such as 131A-B, of the
coupling features on the cutting guide 100. For example, when the
protruding portion 131A is in a shape of rectangular prism, the
corresponding coupling receptacle 331A can be a receptacle in a
shape of rectangular prism sized to securely match the protruding
portion 131A. The interfacing surfaces of the protruding portion
131A and of the coupling receptacle 331A can be processed to allow
for an interference fit in at least one dimension, such that the
protruding portion 131A can be held within the coupling receptacle
331A by compression or by friction. The amount of interference can
be produced at either or both of the interfacing surfaces of the
protruding portion 131A and of the coupling receptacle 331A so as
to achieve desired tightness of fit.
[0027] In some examples, the size and shape of the coupling
receptacle can also be determined using the information including
the location of the landing site of the target bone, and the
anatomical, mechanical, or physical properties of the bone and
surrounding tissues at the landing site. The coupling between the
cut guide 100 and the target bone 300 can therefore be accomplished
by engaging the protruding portions 131A-B into the respective
coupling receptacles 331A-B on the target bone 300. Examples of
creating the coupling receptacles 331A-B for positioning the cut
guide 100 onto the target bone 300 are discussed below, such as
with reference of FIG. 3.
[0028] The landing members 131A-B can be an extended portion of the
guide body 100. In some examples, the landing members 131A-B can be
structures separate from but fixed onto an exterior of the guide
body 100. In an embodiment, at least one of the landing members is
reconfigurable. The reconfigurable landing member can be connected
to the guide body 100 via an adjustable connector, through which
the reconfigurable landing member can have at least one degree of
freedom of movement relative to the guide body 100. Examples of the
adjustable connector can include a releasable lock, such that the
reconfigurable landing member can be adjustably locked onto the
guide body 110 when the reconfigurable landing member is positioned
once the cutting guide is at the landing site and attached to the
target bone, or when the reconfigurable landing member is not used
for attaching to the target bone.
[0029] FIG. 1C illustrates an example of positioning the cut guide
100 onto the target bone 300 such as via coupling between the
protruding portion 131A-B and the coupling receptacles 331A-B. The
guide members 120A-D can guide a cutting tool (not shown) to cut
the target bone 300 along the cutting trajectories 150A-D as
defined by the orientations of the guide members 120A-D. In some
examples, the protruding portions 131A-B of the landing members do
not cross the cutting trajectories or the cutting planes 150A-D.
This will prevent bone cutting along the cutting trajectories from
interfering with the protruding portion 131A-B that are coupled to
the coupling receptacles 331A-B. When the bone cut is completed, an
implant 500 can be attached to the post-operative bone. As
illustrated in FIG. 1D, the implant 500 can include an interfacing
surface sized and shaped to be in close contact with the
post-operative surfaces of the target bone. The interfacing surface
can include multiple facets 550A-D oriented in conformity with the
cutting planes 150A-D, respectively.
[0030] FIGS. 2A-B are block diagrams that illustrate an example of
a cut guide positioning system 200 for use in an orthopedic
surgery. The system 200 includes a cut guide 100, a model receiver
module 210, an input interface 220, a navigation-based guide
coupling preparation system 230, and a communication interface 240.
The system 200 can be configured to securely position the cut guide
100 onto a target bone via two or more coupling receptacles created
on the target bone. Once positioned on the target bone, the cut
guide 100 can be used to guide resection of a portion of the target
bone for prosthesis implantation.
[0031] The model receiver module 210 can be configured to receive a
generic post-coupling bone model (M.sub.coupling). The model
M.sub.coupling can include a data set representing a bone having an
anatomical origin comparable to the target bone to be altered by
the system 200. The data set can include shape or appearance
information of the bone. The model M.sub.coupling can be in a form
of a parametric model, a statistical model, a shape-based model
such as a statistical shape model, or a volumetric model. The model
M.sub.coupling can also be based on physical properties of the
normal bone, such as an elastic model, a geometric spine model, or
a finite element model.
[0032] The model M.sub.coupling can include representations of two
or more coupling receptacles each sized, shaped or otherwise
configured to receive and secure the respective coupling feature on
the cut guide 100, such as protruding portions 131A-B. The coupling
receptacle representation can include indications of locations,
sizes, shapes, volume, or other geometric or morphological
descriptors. In an example, the model M.sub.coupling can be derived
from a plurality of images of post-coupling bones (i.e., bones with
the coupling receptacles created) having comparable anatomical
origin from a group of subjects. In another example, the coupling
receptacle representation includes computer-simulated graphs or
annotative markings that identify the boundaries of the recessed
portions of the coupling receptacle. The sizes, shapes, volume, or
other geometric or morphological descriptors of the coupling
receptacle representations can be determined using the size, shape,
volume, or other geometric or morphological descriptors of the
respective protruding portion (such as 131A-B) of the landing
members on the cut guide 100. The computer-simulated coupling
receptacle representation can be separately generated and then
added to a coupler-free normal bone model to create the generic
post-coupling bone model M.sub.coupling.
[0033] The model M.sub.coupling can be generated using a system
external to the system 200, and stored in a machine-readable medium
such as a memory device. The model receiver module 210 can retrieve
model M.sub.coupling from the memory device upon receiving a
command from an end-user. Alternatively, the system 200 can include
a post-coupling bone model generator that can create a generic
post-coupling bone model (M .sub.coupling) using shape data or
appearance data. The shape data may include geometric
characteristics of a bone such as landmarks, surfaces, boundaries
of three-dimensional images objections. The appearance data may
include both geometric characteristics and intensity information of
a bone. The shape or appearance data can be constructed from a
plurality of medical images of the normal bones of comparable
anatomical origin from a group of subjects. The medical images can
include two-dimensional (2D) or three-dimensional (3D) images,
including an X-ray, an ultrasound image, a computed tomography (CT)
scan, a magnetic resonance (MR) image, a positron emission
tomography (PET) image, or a single-photon emission computed
tomography (SPECT) image, or an arthrogram. The shape or appearance
data can be constructed from a plurality of point clouds acquired
from bones having comparable anatomical origin from a group of
subjects using a coordinated measuring system such as one or more
tracking probes.
[0034] The input interface 220 can be configured to receive a
target bone representation (X.sub.pre-coupling) from a patient
database. Alternatively, the target bone representation
(X.sub.pre-coupling) can be generated by an imaging system or other
image acquisition module within or external to the system 200, and
received by the system 200 via the input interface 220. Examples of
target bone can include an acetabulum, a proximal or distal
extremity of a femur, a proximal or distal extremity of a tibia, or
other bones in a body. The representation X.sub.pre-coupling can be
in a form of a medical image, a point cloud, a parametric model, or
other morphological description of the target bone. The
representation X.sub.pre-coupling includes a data set representing
the shape, appearance, or other morphological characteristics of
the target bone. The representation X.sub.pre-coupling includes two
or more landing site representations on a surface of the target
bone where two or more coupling receptacles can be created.
[0035] The navigation-based guide coupling preparation system 230
can include a cut guide positioning planning module 231 configured
to generate a plan for positioning the cut guide onto or conforming
to the target bone. The cut guide positioning planning module 231
can include a registration module 232 and a positioning plan
formation module 233.
[0036] The registration module 232 can take as an input the generic
post-coupling bone model M.sub.coupling and the target bone
representation X.sub.pre-coupling, register M.sub.coupling to
X.sub.pre-coupling, and create a registered post-coupling bone
model M*.sub.coupling. FIG. 2B is a block diagram illustrating an
embodiment of the registration module 232. In this embodiment, the
registration module 232 can include a segmentation module 271, a
model transformation module 272, a matching module 273, and an
alignment module 274. The segmentation module 271 can be configured
to partition the model M.sub.coupling and the target bone
representation X.sub.pre-coupling each into a plurality of
segments. Each segment can represent a specified anatomical
structure. In some examples, a label can be assigned to each of the
segments, such that the segments with the same label share
specified characteristics such as a shape, anatomical structure, or
intensity. For example, the segmentation module 271 can
differentiate a portion of M.sub.coupling containing the coupling
receptacle representation from a different portion of the
M.sub.coupling free of coupling receptacle representation, and
identify from the segments of the M.sub.coupling a registration
area free of coupling receptacles.
[0037] The model transformation module 272 can transform the
generic post-coupling bone model M.sub.coupling to create the
registered post-coupling model M*.sub.coupling using a comparison
between the coupler-free segment of M.sub.coupling and the
corresponding segments of the X.sub.pre-coupling. The
transformation can include linear or nonlinear operations such as
scaling, rotation, translation, expansion, dilation, or other
affine transformation. The transformation can include rigid
transformations that preserve the distance (such as translation,
rotation, and reflection) or non-rigid transformations such as
stretching, shrinking, or model-based transformations such as
radial basis functions, splines, or finite element model. In some
embodiments, the registration module 232 can employ both the rigid
transformation to bring the M.sub.coupling in global alignment with
the size and orientation of the target bone representation
X.sub.pre-coupling and the non-rigid transformation to reduce the
local geometric discrepancies by aligning the M.sub.coupling with
the X.sub.pre-coupling. In some embodiments, the model
transformation module 272 can determine a desired transformation
.THETA. that minimizes the difference between the identified
coupler-free segments on the M.sub.coupling and the corresponding
segments of X.sub.pre-coupling. The desired transformation
.THETA..sub.opt can then be applied to the M.sub.coupling to create
M e the registered post-coupling model
M*.sub.coupling=.THETA..sub.opt(M.sub.coupling). The model
M*.sub.coupling contains desired size, shape, volume, and other
geometric or morphological descriptors of the coupling receptacles
on the target bone.
[0038] The matching module 273 can match one or more segments of
the registered post-coupling model M*.sub.coupling to the
corresponding registration area of the X.sub.pre-coupling. The
alignment module 274 can align the remaining segments of
M*.sub.coupling with the remaining segments of the target bone
representation X.sub.pre-coupling based at least on the matching.
This produces an alignment between the registered post-coupling
model M*.sub.coupling and the target bone representation
X.sub.pre-coupling.
[0039] Referring back to FIG. 2A, the positioning plan formation
module 233 can use the comparison between the registered
post-coupling model M*.sub.coupling and the target bone
representation X.sub.pre-coupling to determine the two or more
landing sites on the target bone for respectively creating the
coupling receptacles, and determining sizes, shapes, volume, or
other geometric or morphological descriptors of the coupling
receptacles. The comparison can be performed on all or selected
segments (such as the segments containing the coupling receptacles)
of the registered post-coupling model M*.sub.coupling and the
target bone representation X.sub.pre-coupling.
[0040] As illustrated in FIG. 2A, the system 230 can further
include a coupling receptacle preparation tool 235. The coupling
receptacle preparation tool 235 can be a temporary tool used for
producing the two or more coupling receptacles on the landing site
of the target bone according to the positioning plan generated by
the positioning plan formation module 233. The coupling receptacle
preparation tool 235 can be operated manually by an end-user, or
automatically by a computer-controlled system. An example of such a
cutting tool can be found in Brisson et al., U.S. Pat. No.
6,757,582, entitled "Methods and systems to control a shaping
tool", which is incorporated herein by reference in its entirety.
Examples of the coupling receptacle preparation tool and the
creation of the coupling receptacles are discussed below, such as
with reference of FIG. 3.
[0041] In some examples, the coupling receptacle preparation tool
235 is operated to progressively create the coupling receptacles
using a comparison between the registered post-coupling model
M*.sub.coupling and a perioperative target bone representation
X.sub.peri-coupling. The input interface 220 can receive the
perioperative target bone representation X.sub.peri-coupling
including coupling receptacle representations during the process of
creating the coupling receptacles. The perioperative representation
X.sub.peri-coupling can be updated in real-time such as using a
camera and a monitoring device, or upon receiving a user command.
The cut guide positioning planning module 231 can compute a
similarity metric between the desired coupling receptacles on the
registered post-coupling model M*.sub.coupling and the
corresponding perioperative coupling receptacles on the
perioperative target bone representation X.sub.peri-coupling.
Examples of the similarity metric can include L1 norm, L2 norm
(Euclidian distance), infinite norm, or other norm in the normed
vector space. The similarity metric can also include correlation
coefficient, mutual information, or ratio image uniformity. If the
similarity metric meets a specified criterion such as falling
within a specified range or below a threshold value, the
perioperative coupling receptacles on the representation
X.sub.peri-coupling are deemed substantially similar to the desired
coupling receptacle on the registered post-coupling model
M*.sub.coupling, and the positioning plan formation module 233 can
generate an indicator indicating the completion of the coupling
receptacle preparation.
[0042] The communication interface 240, coupled to the
navigation-based guide coupling preparation system 230, can be
configured to present information of the model and the target bone
in audio, visual, or other multi-media formats to assist the
surgeon during the process of creating and evaluating a surgical
plan. The information presented can include the generic
post-coupling bone model M.sub.coupling, the registered
post-coupling model M*.sub.coupling, the target bone representation
X.sub.pre-coupling, the landing sites representation and the
coupling receptacles on the target bone, the perioperative target
bone representation X.sub.peri-coupling, the similarity metric
between the desired coupling receptacles and the perioperative
coupling receptacles, and the indication of the completion of the
coupling receptacle preparation. In an example, the communication
interface 240 can include a display module such as a monitor for
displaying dialog, text, 2D or 3D graphs, or animations of the bone
models and the target bone representation, among other things. The
graphs or animation can include color-codes, annotations, or other
visual enhancements on the perioperative coupling receptacles. The
communication interface 240 can also include a user input device
configured to receive user input to accept or modify the surgical
plan generated by the surgical planning module 130.
[0043] The communication interface 240 can communicate over an
internal bus to other modules within the system 200. In some
examples, the communication interface 240 can be configured to
communicate with one or more external devices including, for
example, a tracking device, a positioning device, a surgical
navigation system, or a medical robotic system. The communication
interface 240 can include both wired interface (such as cables
coupled to the communication ports on the communication interface
240) and wireless connections such as Ethernet, IEEE 802.11
wireless, or Bluetooth, among others.
[0044] FIGS. 3A-B illustrate an example of preparing coupling
receptacles on a target bone 300. In this example, two coupling
receptacles 331A-B are created at two different landing sites
330A-B on the surface of the target bone 300. The coupling
receptacles can be created using a temporary coupling receptacle
preparation tool 335, or any suitable surgical cutting tool,
according to a positioning plan such as generated by the cut guide
positioning planning module 231. The coupling receptacles 331A-B
can each include a respective recessed portion sized, shaped or
otherwise configured to receive and secure a protruding portion of
the coupling feature on the landing members of a cut guide 100,
such as the protruding portions 131A-B. The landing sites 330A-B,
as well as the sizes, shapes, volume, or other geometric or
morphological descriptors of the coupling receptacles, can be
determined by the cut guide positioning planning module 231. In an
example, the size and shape of the coupling receptacles can be
determined based on the size and shape of the protruding portions
131A-B of the landing members. The recessed portion of the coupling
receptacles 331A-B can be in a shape of a cylinder, a cube, a
rectangular prism, a triangular prism, a pyramid, a cone, or other
three-dimensional shapes. The size and shape of the coupling
receptacles can also be determined based on the location of the
landing sites, or based on the anatomical, mechanical, and physical
properties of the bone and soft tissues at the landing sites.
[0045] The temporary coupling receptacle preparation tool 335 can
be an embodiment of the coupling receptacle preparation tool 235.
In an example where the coupling receptacles include recessed
portions such as 331A-B for receiving and securing the protruding
portions of the landing members, the coupling receptacle
preparation tool 335 can include a surgical drill, a surgical mill,
a surgical saw, or other surgical equipment capable of creating the
recessed portion on the target bone. The temporary coupling
receptacle preparation tool 335 can be operated manually by an
operator such as a surgeon. Alternatively, it can be connected to
and operated by an automated computer-controlled system such as a
precision freehand sculptor (PFS) or other robotic surgical
system.
[0046] FIGS. 4A-B are block diagrams that illustrate an example of
an orthopedic surgical system 400 for operating on a target bone.
The system 400 includes a cut guide 100, a model receiver module
410, an input interface 420, a navigation-based guide coupling
preparation system 230, a navigation-based surgical system 450, and
a communication interface 440. The system 400 includes some or all
components of the system 200, and thus can be configured to
position the cut guide 100 onto a target bone via two or more
coupling receptacles created on the target bone. Additionally, the
system 400 can be configured to assist in bone cut after the cut
guide is positioned onto or otherwise conforms to the target
bone.
[0047] The model receiver module 410 can be an embodiment of the
model receiver 210, and can receive a generic post-coupling bone
model (M.sub.coupling). Additionally, the model receiver module 410
can be further configured to receive a generic post-operative bone
model (M.sub.post-op) including a data set representing a shape or
appearance of a post-operative bone (i.e., after the bone cut). The
model M.sub.post-op can be in a form of a parametric model, a
statistical model, a shape-based such as a statistical shape model,
or a volumetric model. The model M.sub.post-op can be derived from
a plurality of images of post-operative bones having comparable
anatomical origin from a group of subjects. Alternatively, at least
a portion of the model M.sub.post-op, such as resected surfaces
that interface with the implant 500, can be computer-simulated
representation of the post-operative bone surface. The
post-operative bone model M.sub.post-op can be generated using an
external system and retrieved from a database, or it can be
generated by a system within or external to the system 400.
[0048] The input interface 420 can be an embodiment of the input
interface 220, and can receive a target bone representation
(X.sub.pre-coupling) including a data set representing the shape,
appearance, or other morphological characteristics of the target
bone including representations of the two or more landing sites on
the target bone. Additionally, the input interface 420 can be
further configured to receive a preoperative target bone
representation including a data set representing a portion of the
target bone to be altered (X.sub.pre-op) which can be different and
broader than the landing sites on the target bone. A set of bone
cuts on the target bone can be determined by the navigation-based
surgical system 450. The representation X.sub.pre-op can include
one of more of a medical image, a point cloud, a parametric model,
or other morphological description of the target bone. In some
examples, the input interface 420 can be configured to be coupled
to an imaging system or other image acquisition module within or
external to the system 400. The post-operative bone model
M.sub.post-op can have data format or modality comparable to the
target bone representation X.sub.pre-op.
[0049] In some embodiments, the representation X.sub.pre-op can be
taken as the post-coupling representation of the target bone, that
is, the target bone presentation X.sub.pre-coupling with two or
more coupling receptacles created according to the navigation-based
guide coupling preparation system 230. The representation
X.sub.pre-op thus includes both a data set representing a portion
of the target bone to be altered as well as the coupling receptacle
representations.
[0050] The navigation-based surgical system 450 can include a
surgical planning module 451 configured to generate a surgical plan
for altering at least a portion of the target bone when the cut
guide is securely positioned onto or otherwise conforms to the
target bone. Similar to the cut guide positioning planning module
231, the surgical planning module 451 can include a registration
module 452 and a surgical plan formation module 453.
[0051] The registration module 452 can be configured to register
M.sub.post-op to X.sub.pre-op and create a registered
post-operative bone model M*.sub.post-op. FIG. 4B is a block
diagram illustrating an embodiment of the registration module 452.
Similar to the registration module 232 in FIG. 2B, the registration
module 452 in this embodiment includes a segmentation module 471, a
model transformation module 472, a matching module 473, and an
alignment module 474. The segmentation module 471 can partition the
bone model M.sub.post-op and the pre-operative bone representation
X.sub.pre-op each into a plurality of segments. Each segment can
represent a specified anatomical structure. In some examples, a
label can be assigned to each of the segments, such that the
segments with the same label share specified characteristics such
as a shape, anatomical structure, or intensity. For example, the
segmentation module 471 can differentiate a portion of the
M.sub.post-op containing the resection surface representation from
a different portion of the M.sub.post-op free of resection surface
representation, and identify from the segments of the M.sub.post-op
a registration area free of resection surface representation.
[0052] The model transformation module 472 can transform the
generic post-coupling bone model M.sub.post-op to create a
registered post-operative bone model M .sub.post-op, such as using
a comparison between the segment of the M.sub.post-op free of
resection surface representation and the corresponding segments of
the X.sub.pre-op. The transformation can include linear or
nonlinear operations, rigid or non-rigid transformations as
discussed with reference to FIG. 2B. The model transformation
module 472 can determine a desired transformation that minimizes
the difference between the identified coupling receptacle-free
segments on the M.sub.post-op and the corresponding segments of
X.sub.pre-op. The desired transformation .omega..sub.opt can then
be applied to the M.sub.post-op to create the registered
post-operative model M*.sub.post-op=.omega..sub.opt(M.sub.post-op).
The model M*.sub.post-op contains desired size, shape, volume, and
other geometric or morphological descriptors of the bone cuts on
the target bone.
[0053] The matching module 473 can match one or more segments of
the registered post-operative model M*.sub.post-op to the
corresponding registration area of the X.sub.pre-op and align the
remaining segments of M*.sub.post-op with the remaining segments
X.sub.pre-op based at least in part on the matching. This produces
an alignment between the registered post-operative model
M*.sub.post-op and the target bone representation X.sub.pre-op.
[0054] The surgical plan formation module 453 can be configured,
using the registered post-operative model M*.sub.post-op, to
generate a surgical plan for cutting the target bone such that the
altered target bone is in substantial conformity to the registered
post-operative model M*.sub.post-op. The surgical plan formation
module 453 can include a guide member selection module to select
one or more guide members from those available (such as 102A-D) on
the cut guide 100. In an embodiment, the guide member selection
module can compare the orientations of the desired bone cuts as
defined by the registered post-operative model M*.sub.post-op to
the cutting trajectories of the available guide members in the cut
guide 100, and select the guide members that match the orientation
of the desired bone cuts.
[0055] The surgical plan formation module 453 can also include a
cutting sequence scheduler module to determine an ordered sequence
of executing bone cuts along the cutting trajectories (such as
150A-D) associated with the selected guide members. The cutting
sequence can be determined using the anatomical, geometric,
physical and mechanical properties of the portions of the bone to
be altered. The cutting sequence can also be scheduled considering
the locations, sizes, shapes, volumes, or other geometric or
morphological descriptors of the coupling receptacles relative to
the cutting trajectories. For example, the bone cuts along the
cutting trajectories that are spatially farther away from the
coupling receptacles can be executed earlier (i.e., at the front of
the sequence), the bone cuts along the cutting trajectories that
are spatially closer to the coupling receptacles can be executed
later (i.e., at a latter part of the sequence), and the bone cuts
along the cutting trajectories that intersect with one or more
coupling receptacles can be executed last (i.e., at the end of the
sequence). The ordered bone cuts as such allow the cut guide to
remain securely attached to the target bone while performing bone
cuts, and prevent a bone cut from interfering with the coupling
between the cut guide and the target bone. Examples of selecting
guide members and generating an ordered bone cut sequence are
discussed below, such as with reference of FIGS. 5A-C.
[0056] As illustrated in FIG. 4A, the navigation-based surgical
system 450 can further include a surgical tool 455 for resecting
the target bone according to the surgical plan such as generated by
the surgical planning module 451. The surgical tool 455 can be
adjustably positioned within the guide members, and can securely
move along the cutting trajectories defined by the guide members.
Examples of the surgical too can include a surgical saw, a surgical
blade, a surgical saw-blade, a surgical mill, or other surgical
equipment. The surgical tool 455 can be operated manually by an
end-user such as a surgeon. Alternatively, the surgical tool 455
can be connected to and operated by an automated
computer-controlled system such as a precision freehand sculptor
(PFS) or other robotic surgical.
[0057] In some examples, perioperative target bone representation
during the bone cuts can be updated in real-time such as using a
camera and a monitoring device, or upon receiving a user command.
The surgical planning module 451 can compute a similarity metric
between the desired bone cuts on M.sub.post-op and the
perioperative bone cuts, and determines the bone cuts on the target
bone are completed if the similarity metric meets a specified
criterion such as falling within a specified range or below a
threshold value. The surgical plan formation module 453 can
generate an indicator indicating the completion of the bone
cut.
[0058] The communication interface 440 can be an embodiment of the
communication interface 240, and can generate and display on a
display module one or more of the generic post-coupling bone model
(M -coupling) and the target bone representations
(X.sub.pre-coupling), among other information as discussed with
reference to FIG. 2A. Additionally, the communication interface 440
can further be configured to generate and display on the display
module one or more of the data set representing the portion of the
target bone to be altered (X.sub.pre-op), the generic
post-operative bone model (M.sub.post-op), the selected guide
members on the cut guide, the scheduled sequence of bone cuts along
the cutting trajectories, the perioperative target bone
representation during bone cutting, and the indication of the
completion of bone cuts.
[0059] FIGS. 5A-C illustrate an example of selecting a set of guide
members and generating an ordered sequence of bone cuts along the
trajectories associated with the selected guide members. FIG. 5A
illustrates a registered generic post-operative bone model 510,
which can be an embodiment of M*.sub.post-op. The model 510 has
desired resection surface representations defined by flat facets
520A-D. The resection surface representations can be derived from a
plurality of images of post-operative bones having comparable
anatomical origin from a group of subjects. Alternatively, the
resection surface representations can be computer-simulated
representations created based on the shape of the surfaces 550A-D
of the bone implant to be interfaced with the resected target
bone.
[0060] The orientations of the flat facets 520A-D can be compared
to the cutting trajectories of the available guide members 120A-D
on the cut guide 100, as illustrated in FIG. 5B. The flat facets
520A-D are determined to match the trajectories defined by guide
members 120A-D, respectively; hence the guide members 120A-D can be
selected for bone cutting. Although in this example all guide
members 120A-D available in the cut guide 100 are selected, in
other examples where the cut guide includes multiple or redundant
guide members, only a subset rather than all of the available guide
members are necessarily selected to match the orientation of the
desired bone cuts. In some examples, two or more guide members
having parallel trajectories can be selected, and the bone cuts can
be executed along the parallel trajectories one at a time to
progressively resect the target bone in multiple layers.
[0061] An ordered bone cut sequence can be decided by comparing the
locations, sizes, shapes, volumes, or other geometric or
morphological descriptors of the coupling receptacles and the
cutting trajectories of the selected guide members 120A-D. For
example, the trajectories of the guide members 120A and 120C shown
in FIG. 5B are farther away from, and therefore less likely to
interfere with, the coupling receptacles at the landing sites 330A
and 330B as illustrated in FIG. 5C. The trajectory of the guide
member 120B is close to, and is likely to interfere with, the
landing site 330A. The trajectory of the guide member 120D is close
to, and is likely to interfere with, both the landing sites 330A
and 330B. Therefore, bone cuts along the trajectories associated
with 120A-C can be performed first, the trajectory associated with
120B next, and the trajectory associated with 120D the last.
[0062] FIG. 6 is a flowchart that illustrates an example of a
method 600 for operating a system to generate a cut guide
positioning plan for positioning a cut guide onto a target bone. In
an embodiment, the cut guide 100 and the cut guide positioning
system 200, including their respective various embodiments
discussed in this document, can be configured to perform method
600, including its various embodiments discussed in this
document.
[0063] The method 600 can begin at 610 with receiving a
representation of a target bone, such as by using the input
interface 220. The target bone, such as a portion of a femur, a
tibia, or other bone or articulation in the body, can be scheduled
for surgical alteration, resection, or repair. The target bone
representation includes two or more landing sites on the target
bone, such as surfaces of an acetabulum, a proximal or distal
extremity of a femur, or a proximal or distal extremity of a tibia.
The target bone representation X.sub.pre-coupling can include a
data set representing the shape, appearance, contour, or other
geometric or morphological characteristics of the target bone. The
target bone representation can also include intensity information.
The representation X.sub.pre-coupling can include one of more of a
medical image, a point cloud, a parametric model, or other
morphological description of the target bone. Examples of medical
images can include an X-ray, an ultrasound image, a computed
tomography (CT) scan, a magnetic resonance (MR) image, a positron
emission tomography (PET) image, a single-photon emission computed
tomography (SPECT) image, or an arthrogram, among other 2D or 3D
images.
[0064] At 620, a cut guide can be selected such as by a cut guide
selection module. The cut guide can be selected based on the size,
shape, anatomy, and mechanical properties of the target bone, such
that the selected cut guide can be appropriately used in assisting
bone cuts on the target bone. The selected cut guide, such as the
cut guide 100, can include one or more guide members on the body of
the cut guide with pre-determined cutting trajectories, and a
plurality of landing members each including a respective coupling
feature configured to removably couple to a landing site of the
target bone.
[0065] At 630, a generic post-coupling bone model (M.sub.coupling)
is received, such as by using the model receiver module 210. The
model M.sub.coupling may be derived from a plurality of images of
bones taken from a group of subjects, where the images can have
anatomical origin similar to the target bone representation
X.sub.pre-coupling. The model M.sub.coupling can be in a form of a
parametric model, a statistical model, a shape-based model such as
a statistical shape model, a volumetric model, an elastic model, a
geometric spine model, or a finite element model. In addition to
the representation of the shape and morphology of the bone, the
model M.sub.coupling can include representations of two or more
coupling receptacles produced at respective two or more landing
sites on the bone. An example of the coupling receptacle includes
recessed portions created at specified landing sites on the target
bone. Each coupling receptacle is sized, shaped or otherwise
configured to receive and secure the respective coupling feature of
the landing members on the cut guide. The representations of the
two or more coupling receptacles can include indications of the
location on the model M.sub.coupling, size, shape, volume, or other
geometric or morphological descriptors. In an embodiment, the
coupling receptacle representation can be computer-simulated based
on the size, shape, volume, or other geometric or morphological
descriptors of the coupling features on the landing members of the
cut guide. The computer-simulated coupling receptacle
representations can be added to the coupler-free normal bone model
to create a post-coupling bone model M.sub.coupling.
[0066] At 640, a cut guide positioning plan for positioning the cut
guide onto or conforming to the target bone is generated, such as
by using the navigation-based guide coupling preparation system
230. To generate the cut guide positioning plan, the generic
post-coupling bone model M.sub.coupling can be registered to the
target bone representation X.sub.pre-coupling to create a
registered post-coupling model M.sub.coupling. In one embodiment,
the registration includes a process of segmentation, model
transformation, and matching and alignment between the target bone
representation and the transformed or registered model. The bone
model M.sub.coupling and the target bone representation
X.sub.pre-coupling can each be partitioned into a plurality of
segments representing various anatomical structures on the
respective image. The portion of the M.sub.coupling that contains
the coupling receptacle representation can be differentiated from
other portions of the M.sub.coupling free of coupling receptacle
representation, and a registration area free of coupling receptacle
representation can be identified from the segments of the
M.sub.coupling. Using a comparison between the coupler-free segment
of M.sub.coupling and the corresponding segments of
X.sub.pre-coupling, a desired transformation can be determined
which minimizes the difference between the identified coupling
receptacle-free segments on the M.sub.coupling and the
corresponding segments of X.sub.pre-coupling. The desired
transformation can then be applied to the model M.sub.coupling to
create the registered post-coupling model M*.sub.coupling. One or
more segments of the registered post-coupling model M*.sub.coupling
can then be matched to the corresponding registration area of the
X.sub.pre-coupling, and the remaining segments of the registered
post-coupling model M*.sub.coupling can be aligned with the
remaining segments of the target bone representation
X.sub.pre-coupling based on the matching.
[0067] The registered post-coupling model M*.sub.coupling can then
be compared to the target bone representation X.sub.pre-coupling to
determine the landing sites for creating the two or more coupling
receptacles, and to determine size, shape, and other geometric or
morphological descriptors of the coupling receptacles. The landing
sites of the coupling receptacles can also be determined using
information about the cut guide, including size and shape of the
coupling features of the landing members, and the cutting
trajectories associated with the guide members.
[0068] The cut guide positioning plan can be used by a system, such
as the cut guide positioning system 200, for locating the landing
sites on the target bone, and controlling a surgical cutting tool
to produce two or more coupling receptacles to desired size and
shape at the landing sites. The surgical cutting tool, such as a
surgical drill, a surgical mill, a surgical saw, or other surgical
equipment, can be manually operated or driven by an automated
computer-controlled system. The cut guide can therefore be
positioned onto or conform to the target bone via the established
coupling between the coupling features on the cut guide and the
coupling receptacles created on the target bone.
[0069] To ensure tight and secure coupling, the method 600 can
optionally include an operation of processing the interfacing
surfaces of the coupling receptacle to allow for an interference
fit in at least one dimension between the coupling features and the
coupling by compression or by friction. The amount of interference
can be produced at the coupling receptacle to achieve desired
tightness of fit. The positioning can be performed manually by an
operator or with the assist of an automated system such as a
computer-controlled robotic arm. Examples of methods for creating
the coupling receptacle in accordance with the cut guide positing
plan are discussed below, such as with reference of FIG. 7.
[0070] In some embodiments, the method 600 can further includes
providing audio, visual, or other multi-media presentations of the
post-coupling bone model M.sub.coupling the registered
post-coupling model M*.sub.coupling, the target bone
representation, among other things. The presentation can be
displayed on a monitor or other communication interface. The
presentation formats can also include sound, dialog, text, 2D or 3D
graphs, or animations to assist an end-user such as a surgeon
during the process of creating and evaluating the cut guide
positioning plan. Presentation of the coupling between the target
bone model and the cut guide, including a measurement of relative
positions between the coupling feature and the respective coupling
receptacle, can also be provided to the end-user when the cut guide
is positioned onto or conform to the target bone.
[0071] FIG. 7 is a flowchart that illustrates an example of a
method 700 for producing coupling receptacles on a target bone. The
method 700 can be used for progressively creating bond couplers
using a navigation-based feedback-controlled mechanism. The method
700 can be an embodiment of producing coupling receptacles on the
target bone at 650 in method 600.
[0072] A cut guide positioning plan, including a registered
post-coupling bone model M*.sub.coupling, is generated at 710. The
cut guide positioning plan and the post-coupling bone model
M*.sub.coupling can be generated using the steps 610-640 in the
method 600. At 720, a perioperative target bone representation
X.sub.peri-coupling can be received. The perioperative target bone
representation X.sub.peri-coupling can include a data set
representing the target bone with two or more coupling receptacles
during the coupling receptacle creation process. Prior to the
coupling receptacle creating, the perioperative target bone
representation X.sub.peri-coupling can be initialized to the target
bone representation X.sub.pre-coupling.
[0073] At 730, a similarity metric between the coupling receptacles
on the model M*.sub.coupling and the corresponding perioperative
coupling receptacles on the representation X.sub.peri-coupling is
computed. In an embodiment, statistical or morphological features
representing sizes, shapes, volume, or other geometric or
morphological descriptors of the coupling receptacles can be
extracted from M*.sub.coupling and X.sub.peri-coupling. Similarity
metric can be computed using the statistical or morphological
features of the model M*.sub.coupling and those of the
representation X.sub.peri-coupling. Examples of the similarity
metric can include L1 norm, L2 norm (Euclidian distance), infinite
norm, or other norm in the normed vector space. The similarity
metric can also include correlation coefficient, mutual
information, or ratio image uniformity.
[0074] The similarity metric can be provided to the operator such
as a surgeon via a displaying module, or to an automated
computer-controlled system. At 740, the similarity metric can be
compared to specified criterion such as a pre-determined threshold
value. If the similarity metric fails to meet the specified
criterion, the coupling receptacle creation process continues at
750 with further bone cut according to the positioning plan, and
peri-operative bone representation can be re-generated at 720. The
navigation-based feedback-controlled coupling receptacle creation
process then continues. If, however, the similarity metric meets
the specified criterion, the perioperative coupling receptacles on
X.sub.peri-coupling are deemed substantially similar to the desired
coupling receptacles on the model M*.sub.coupling. An indicator can
then be generated to indicate a completion of the coupling
receptacle creation process at 760.
[0075] FIG. 8 is a flowchart that illustrates an example of a
method 800 for resecting a portion of a target bone using a cut
guide. In an embodiment, the cut guide 100 and the orthopedic
surgical system 400, including their respective various embodiments
discussed in this document, can be configured to perform method
800, including its various embodiments discussed in this
document.
[0076] At 810, a cut guide, such as the cut guide 100, can be
positioned onto a target bone. In an embodiment, positioning the
cut guide can be performed using the method 600. A target bone
representation (X.sub.pre-op) is received at 820. The
representation X.sub.pre-op can include a data set representing a
portion of the target bone to be altered. For example, the
representation X.sub.pre-op can include a medical image, a point
cloud, a parametric model, or other morphological description of
the target bone. In some embodiments, the X.sub.pre-op can include
a representation of the target bone following the creation of the
coupling receptacles.
[0077] At 830, a generic post-operative bone model (M.sub.post-op)
is received. The model M.sub.post-op can include a data set
representing a post-operative bone (i.e., after the bone cut)
having an anatomical origin comparable to the target bone. The
model M.sub.post-op can be in a form of a parametric model, a
statistical model, a shape-based model such as a statistical shape
model, or a volumetric model. In an example, the model
M.sub.post-op can be derived from a plurality of images of
post-operative bones of comparable anatomical origin from a group
of subjects. Alternatively, at least a portion of the
post-operative bone model M.sub.post-op, such as the resection
surfaces that interface with an implant, can be computer-simulated
representation of the post-operative bone surface.
[0078] At 840, a surgical plan for altering a portion of the target
bone can be created when the cut guide is securely positioned onto
or conforms to the target bone.
[0079] The post-operative bone model M.sub.post-op can be
registered to the representation X.sub.pre-op to create a
registered post-operative bone model M*.sub.post-op. Similar to the
process of registering the generic post-coupling bone model
M.sub.coupling to the target bone representation X.sub.pre-coupling
as discussed above in FIG. 6, the registration can include a
process of segmentation, model transformation, and matching and
alignment between X.sub.pre-op and M*.sub.post-op. In particular,
after portioning the model M.sub.post-op and the pre-operative bone
representation X.sub.pre-op each into a plurality of segments, the
generic post-coupling bone model M.sub.post-op can be transformed
to create a registered post-operative bone model M*.sub.post-op,
such as using a comparison between the segment of the M.sub.post-op
free of resection surface representation and the corresponding
segments of the X.sub.pre-op. One or more segments of the
registered post-operative bone modelM*.sub.post-op can then be
matched to the corresponding registration area of the X.sub.pre-op.
The remaining segments of the registered post-operative bone model
M*.sub.post-op can be aligned with the remaining segments of
X.sub.pre-op based on the matching.
[0080] A surgical plan can then be generated using the registered
post-operative model M*.sub.post-op for cutting the target bone
until the altered target bone is in substantial conformity with the
registered post-operative model M*.sub.post-op. The orientations of
the desired resection surface as defined by the registered
post-operative model M*.sub.post-op can be compared to the cutting
trajectories of the guide members of the cut guide. One or more
guide members that match the orientation of a portion of the
resection surface can then selected. An ordered sequence of bone
cuts along the trajectories associated with the selected guide
members is then determined. The cutting sequence can be determined
using the anatomical, geometric, physical and mechanical properties
of the portions of the bone to be altered. The cutting sequence can
also be scheduled considering the locations, sizes, shapes,
volumes, or other geometric or morphological descriptors of the
coupling receptacles relative to the cutting trajectories. For
example, the bone cuts along the cutting trajectories that are
spatially farther away from the coupling receptacles can be
executed earlier (i.e., at the front of the sequence), the bone
cuts along the cutting trajectories that are spatially closer to
the coupling receptacles can be executed later (i.e., at a latter
part of the sequence), and the bone cuts along the cutting
trajectories that intersect with one or more coupling receptacles
can be executed last (i.e., at the end of the sequence). The
ordered bone cuts as such allow the cut guide to remain securely
attached to the target bone while performing bone cuts, and prevent
a bone cut from interfering with the coupling between the cut guide
and the target bone.
[0081] The target bone can then be altered at 850 in accordance
with the surgical plan. A cutting tool can be positioned in the
selected guide members of the cut guide and resect portions of the
target bone along the cutting trajectories in the determined
ordered sequence. Bone cutting can be performed manually by an
operator or with the assist of an automated system such as a
computer-controlled robotic arm. In some examples, the method 800
can further include presenting, on a display module or a
communication interface, audio, visual, or other multi-media
presentations of one or more of the data set representing the
portion of the target bone to be altered (X.sub.pre-op), the
generic post-operative bone model (M.sub.post-op) the selected
guide members on the cut guide, and the scheduled sequence of bone
cuts along the cutting trajectories, among other things.
[0082] FIG. 9 is a block diagram that illustrates an example of a
machine in the form of a computer system 900 within which
instructions, for causing the computer system to perform any one or
more of the methods discussed herein, may be executed. In various
embodiments, the machine can operate as a standalone device or may
be connected (e.g., networked) to other machines. In a networked
deployment, the machine may operate in the capacity of a server or
a client machine in server-client network environment, or as a peer
machine in a peer-to-peer (or distributed) network environment. The
machine may be a personal computer (PC), a tablet PC, a set-top box
(STB), a PDA, a cellular telephone, a web appliance, a network
router, switch or bridge, or any machine capable of executing
instructions (sequential or otherwise) that specify actions to be
taken by that machine. Further, while only a single machine is
illustrated, the term "machine" shall also be taken to include any
collection of machines that individually or jointly execute a set
(or multiple sets) of instructions to perform any one or more of
the methodologies discussed herein.
[0083] The example computer system 900 includes a processor 902
(such as a central processing unit (CPU), a graphics processing
unit (GPU), or both), a main memory 904 and a static memory 906,
which communicate with each other via a bus 908. The computer
system 900 may further include a video display unit 910 (such as a
liquid crystal display (LCD) or a cathode ray tube (CRT)), an
alpha-numeric input device 912 (such as a keyboard), a user
interface (UI) navigation device (or cursor control device) 914
(such as a mouse), a disk drive unit 916, a signal generation
device 918 (e.g., a speaker) and a network interface device
920.
[0084] The disk drive unit 916 includes a machine-readable storage
medium 922 on which is stored one or more sets of instructions and
data structures (e.g., software) 924 embodying or used by any one
or more of the methods or functions described herein. The
instructions 924 may also reside, completely or at least partially,
within the main memory 904, static memory 906, and/or within the
processor 902 during execution thereof by the computer system 900,
the main memory 904 and the processor 902 also constituting
machine-readable media. In an example, the instructions 924 stored
in the machine-readable storage medium 922 include instructions
causing the computer system 900 to receive receive a target bone
representation including a data set representing two or more
landing sites of the target bone (X.sub.pre-coupling), to select a
cut guide configured to be adjustably positionable onto or
otherwise to conform to the target bone, and to receive a generic
post-coupling bone model (M.sub.coupling) including a data set
representing a bone having the two or more coupling receptacles.
The instructions 924 can also store the instructions 924 that cause
the computer system 900 to generate a cut guide positioning plan
for positioning the cut guide onto or conforming to the target
bone.
[0085] The machine-readable storage medium 922 may further store
the instructions 924 that cause the computer system 900 to produce,
respectively at the two or more landing sites, the two or more
coupling receptacles sized, shaped or otherwise configured to
receive and secure the respective coupling feature of each of the
plurality of landing members, and to attach the cut guide to the
landing site of the target bone by respectively engaging the
coupling features with the coupling receptacles. The instructions
in the machine-readable storage medium 922 may also cause the
computer system 900 to receive a target bone representation
including a data set representing a portion of the target bone to
be altered, receive a generic post-operative bone model including a
data set representing a post-operative bone having an anatomical
origin comparable to the target bone, generate a surgical plan for
altering a portion of the target bone when the cut guide is
securely positioned onto or otherwise conforms to the target bone,
and alter the target bone in accordance with the surgical plan
using the cutting tool and the cut guide.
[0086] While the machine-readable medium 922 is shown in an example
embodiment to be a single medium, the term "machine-readable
medium" may include a single medium or multiple media (e.g., a
centralized or distributed database, and/or associated caches and
servers) that store the one or more instructions or data
structures. The term "machine-readable storage medium" shall also
be taken to include any tangible medium that is capable of storing,
encoding or carrying instructions for execution by the machine and
that cause the machine to perform any one or more of the methods of
the present invention, or that is capable of storing, encoding or
carrying data structures used by or associated with such
instructions. The term "machine-readable storage medium" shall
accordingly be taken to include, but not be limited to, solid-state
memories, and optical and magnetic media. Specific examples of
machine-readable media include non-volatile memory, including by
way of example, semiconductor memory devices (e.g., erasable
programmable read-only memory (EPROM), electrically erasable
programmable read-only memory (EEPROM)) and flash memory devices;
magnetic disks such as internal hard disks and removable disks;
magneto-optical disks; and CD-ROM and DVD-ROM disks. A
"machine-readable storage medium" shall also include devices that
may be interpreted as transitory, such as register memory,
processor cache, and RAM, among others. The definitions provided
herein of machine-readable medium and machine-readable storage
medium are applicable even if the machine-readable medium is
further characterized as being "non-transitory." For example, any
addition of "non-transitory," such as non-transitory
machine-readable storage medium, is intended to continue to
encompass register memory, processor cache and RAM, among other
memory devices.
[0087] In various examples, the instructions 924 may further be
transmitted or received over a communications network 926 using a
transmission medium. The instructions 924 may be transmitted using
the network interface device 920 and any one of a number of
well-known transfer protocols (e.g., HTTP). Examples of
communication networks include a LAN, a WAN, the Internet, mobile
telephone networks, plain old telephone (POTS) networks, and
wireless data networks (e.g., Wi-Fi and WiMAX networks). The term
"transmission medium" shall be taken to include any intangible
medium that is capable of storing, encoding or carrying
instructions for execution by the machine, and includes digital or
analog communications signals or other intangible media to
facilitate communication of such software.
[0088] The above detailed description includes references to the
accompanying drawings, which form a part of the detailed
description. The drawings show, by way of illustration, specific
embodiments in which the invention can be practiced. These
embodiments are also referred to herein as "examples." Such
examples can include elements in addition to those shown or
described. However, the present inventors also contemplate examples
in which only those elements shown or described are provided.
Moreover, the present inventors also contemplate examples using any
combination or permutation of those elements shown or described (or
one or more aspects thereof), either with respect to a particular
example (or one or more aspects thereof), or with respect to other
examples (or one or more aspects thereof) shown or described
herein.
[0089] In the event of inconsistent usages between this document
and any documents so incorporated by reference, the usage in this
document controls.
[0090] In this document, the terms "a" or "an" are used, as is
common in patent documents, to include one or more than one,
independent of any other instances or usages of "at least one" or
"one or more." In this document, the term "or" is used to refer to
a nonexclusive or, such that "A or B" includes "A but not B," "B
but not A," and "A and B," unless otherwise indicated. In this
document, the terms "including" and "in which" are used as the
plain-English equivalents of the respective terms "comprising" and
"wherein." Also, in the following claims, the terms "including" and
"comprising" are open-ended, that is, a system, device, article,
composition, formulation, or process that includes elements in
addition to those listed after such a term in a claim are still
deemed to fall within the scope of that claim. Moreover, in the
following claims, the terms "first," "second," and "third," etc.
are used merely as labels, and are not intended to impose numerical
requirements on their objects.
[0091] Method examples described herein can be machine or
computer-implemented at least in part. Some examples can include a
computer-readable medium or machine-readable medium encoded with
instructions operable to configure an electronic device to perform
methods as described in the above examples. An implementation of
such methods can include code, such as microcode, assembly language
code, a higher-level language code, or the like. Such code can
include computer readable instructions for performing various
methods. The code may form portions of computer program products.
Further, in an example, the code can be tangibly stored on one or
more volatile, non-transitory, or non-volatile tangible
computer-readable media, such as during execution or at other
times. Examples of these tangible computer-readable media can
include, but are not limited to, hard disks, removable magnetic
disks, removable optical disks (e.g., compact disks and digital
video disks), magnetic cassettes, memory cards or sticks, random
access memories (RAMs), read only memories (ROMs), and the
like.
[0092] The above description is intended to be illustrative, and
not restrictive. For example, the above-described examples (or one
or more aspects thereof) may be used in combination with each
other. Other embodiments can be used, such as by one of ordinary
skill in the art upon reviewing the above description. The Abstract
is provided to comply with 37 C.F.R. .sctn.1.72(b), to allow the
reader to quickly ascertain the nature of the technical disclosure.
It is submitted with the understanding that it will not be used to
interpret or limit the scope or meaning of the claims. Also, in the
above Detailed Description, various features may be grouped
together to streamline the disclosure. This should not be
interpreted as intending that an unclaimed disclosed feature is
essential to any claim. Rather, inventive subject matter may lie in
less than all features of a particular disclosed embodiment. Thus,
the following claims are hereby incorporated into the Detailed
Description as examples or embodiments, with each claim standing on
its own as a separate embodiment, and it is contemplated that such
embodiments can be combined with each other in various combinations
or permutations. The scope of the invention should be determined
with reference to the appended claims, along with the full scope of
equivalents to which such claims are entitled.
* * * * *