U.S. patent application number 17/396656 was filed with the patent office on 2021-11-25 for systems and methods for intra-operative image analysis.
The applicant listed for this patent is Depuy Synthes Products, Inc.. Invention is credited to Cameron Albert, Andrew J. Cooper, Xiu Jiang, Noah D. Wollowick.
Application Number | 20210361252 17/396656 |
Document ID | / |
Family ID | 1000005764556 |
Filed Date | 2021-11-25 |
United States Patent
Application |
20210361252 |
Kind Code |
A1 |
Wollowick; Noah D. ; et
al. |
November 25, 2021 |
SYSTEMS AND METHODS FOR INTRA-OPERATIVE IMAGE ANALYSIS
Abstract
A system and method for analyzing images to optimize orthopaedic
functionality at a site within a patient, including obtaining at
least a first, reference image of the site, or a corresponding
contralateral site, the first image including at least a first
anatomical region or a corresponding anatomical region. At least a
second, intra-operative results image of the site is obtained. At
least one point is selected to serve as a reference for both images
during analysis including at least one of scaling, calculations,
and image comparisons.
Inventors: |
Wollowick; Noah D.;
(Westport, CT) ; Cooper; Andrew J.; (Largo,
FL) ; Jiang; Xiu; (Powhatan, VA) ; Albert;
Cameron; (Powhatan, VA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Depuy Synthes Products, Inc. |
Raynham |
MA |
US |
|
|
Family ID: |
1000005764556 |
Appl. No.: |
17/396656 |
Filed: |
August 7, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16690392 |
Nov 21, 2019 |
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17396656 |
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14630300 |
Feb 24, 2015 |
10758198 |
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16690392 |
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61944520 |
Feb 25, 2014 |
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61948534 |
Mar 5, 2014 |
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61980659 |
Apr 17, 2014 |
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62016483 |
Jun 24, 2014 |
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62051238 |
Sep 16, 2014 |
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62080953 |
Nov 17, 2014 |
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62105183 |
Jan 19, 2015 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 2034/108 20160201;
A61B 6/12 20130101; A61B 34/10 20160201; G06T 7/0014 20130101; A61B
2034/2068 20160201; G06T 2207/30008 20130101; G06T 2207/10116
20130101; G06T 2207/30052 20130101; G06T 7/33 20170101; A61B 6/463
20130101; A61B 6/5235 20130101; A61B 6/505 20130101 |
International
Class: |
A61B 6/00 20060101
A61B006/00; A61B 6/12 20060101 A61B006/12; A61B 34/10 20060101
A61B034/10; G06T 7/33 20060101 G06T007/33; G06T 7/00 20060101
G06T007/00 |
Claims
1. A system to provide intraoperative analysis related to an
acetabular component, the system comprising: a memory, and a
processor coupled to the memory, wherein the processor is
configured to: obtain an image of a surgical site of a patient with
the acetabular component installed; identify the acetabular
component in the image, wherein identifying the acetabular
component comprises determining an acetabular component bottom and
including a plurality of positioning arcs corresponding to the
acetabular component bottom in the image; and determine anteversion
information based on the positioning arcs.
2. The system of claim 1, wherein the processor is further
configured to display guide handles to facilitate position
adjustment of at least one of the positioning arcs.
3. The system of claim 1, wherein the processor is further
configured to display a slider control to facilitate size
modification of the positioning arcs.
4. The system of claim 3, wherein the processor is further
configured to contemporaneously update the anterversion information
in response to the size modification of the positioning arcs.
5. The system of claim 1, wherein the processor is further
configured to determine an abduction angle, wherein the abduction
angle is formed at the intersection of a neutral axis line and an
abduction line.
6. The system of claim 5, wherein: with the slider control at one
end of the slider range, the positioning arcs overlay the abduction
line, and with the slider control at another end of the slider
range, the positioning arcs overlay a hemispherical surface of the
acetabular component in the image.
7. The system of claim 5, wherein to determine the abduction angle,
the processor is configured to determine a left ischial tuberosity
and a right ischial tuberosity in the image.
8. The system of claim 7, wherein the neutral axis line touches a
left ischial tuberosity and a right ischial tuberosity in the
image.
9. The system of claim 5, wherein the abduction line runs along the
acetabular component bottom in the image.
10. The system of claim 1, wherein the acetabular component
comprises one of a standard acetabular cup, or a reamer, or a trial
acetabular cup
11. A processor-implemented method to provide intraoperative
analysis related to an acetabular component, the method comprising:
obtaining an image of a surgical site of a patient with the
acetabular component installed; identifying the acetabular
component in the image, wherein identifying the acetabular
component comprises determining an acetabular component bottom and
including a plurality of positioning arcs corresponding to the
acetabular component bottom in the image; and determining
anteversion information based on the positioning arcs.
12. The method of claim 11, further comprising displaying guide
handles to facilitate position adjustment of at least one of the
positioning arcs.
13. The method of claim 11, further comprising displaying a slider
control to facilitate size modification of the positioning
arcs.
14. The method of claim 13, further comprising contemporaneously
updating the anterversion information in response to performing
size modification of the positioning arcs.
15. The method of claim 11, further comprising determining an
abduction angle, wherein the abduction angle is formed at the
intersection of a neutral axis line and an abduction line.
16. The method of claim 15, wherein: with the slider control at one
end of the slider range, the positioning arcs overlay the abduction
line, and with the slider control at another end of the slider
range, the positioning arcs overlay a hemispherical surface of the
acetabular component in the image.
17. The method of claim 15, wherein determining the abduction angle
comprises determining a left ischial tuberosity and a right ischial
tuberosity in the image, wherein the neutral axis line touches the
left ischial tuberosity and the right ischial tuberosity.
18. A non-transitory computer-readable medium comprising executable
instructions to provide intraoperative analysis related to an
acetabular component by configuring a processor to: obtain an image
of a surgical site of a patient with the acetabular component
installed; identify the acetabular component in the image, wherein
identifying the acetabular component comprises determining an
acetabular component bottom and including a plurality of
positioning arcs corresponding to the acetabular component bottom
in the image; and determine anteversion information based on the
positioning arcs.
19. The computer-readable medium of claim 18, wherein the
executable instructions further configure the processor to display
a slider control to facilitate size modification of the positioning
arcs.
20. The computer-readable medium of claim 19, wherein the
executable instructions further configure the processor to
contemporaneously update the anterversion information in response
to the size modification of the positioning arcs.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. Non-Provisional
application Ser. No. 16/690,392 filed Nov. 21, 2019, which is a
continuation of U.S. Non-Provisional application Ser. No.
14/630,300 filed on Feb. 24, 2015 (now U.S. Pat. No. 10,758,198),
which claims priority to: U.S. Provisional Application No.
61/944,520 filed Feb. 25, 2014, U.S. Provisional Application No.
61/948,534 filed Mar. 5, 2014, U.S.
[0002] Provisional Application No. 61/980,659 filed Apr. 17, 2014,
U.S. Provisional Application No. 62/016,483 filed Jun. 24, 2014,
U.S. Provisional Application No. 62/051,238 filed Sep. 16, 2014,
U.S. Provisional Application No. 62/080,953 filed Nov. 17, 2014,
and U.S. Provisional Application No. 62/105,183 filed Jan. 19,
2015. All of the above applications are incorporated by reference
herein in their entireties.
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0003] The invention relates to analysis of images of features
within a patient and more particularly to accurately scaling and/or
analyzing such images during surgery.
2. Brief Description of the Prior Art
[0004] Orthopedic surgeons and other healthcare professionals
commonly rely on surgical guidance techniques that can be broadly
classified in two categories: pre-operative digital templating or
training systems that enable pre-surgical planning, and
computer-assisted navigation systems providing intra-operative
guidance for placement and movement of surgical instruments within
a patient. There are benefits to both of these technologies, but
each has respective limitations.
[0005] Preoperative digital templating techniques enable
preoperative surgical planning by utilizing digital or hard copy
radiographic images or similar X-ray-type, scaled according to an
object of known size. Commonly, a spherical ball marker of known
size is placed between the legs or next to the hip of a patient
undergoing hip surgery so that it appears in the image; the ball
marker is then utilized as a reference feature for image scaling.
This preoperative scaling technique has inherent limitations to
accuracy because it assumes that the bones within a patient and the
surface ball marker will magnify at the same ratio. Commonly, the
surgeon will realize during the surgery that this scale factor is
inaccurate, due to deviations in magnification ratios, rendering
the preoperative template ineffective for intraoperative decision
making. For emergency cases such as hip fractures, preoperative
digital templating often cannot be utilized, because the X-ray
images are taken in a hospital setting without utilizing a ball
marker or other scaling device.
[0006] Surgeons also have the option of utilizing computer-assisted
navigation systems which provide intraoperative guidance. The
purported benefits of computer navigation include reduction of
outliers and adverse outcomes related to intraoperative positioning
of surgical hardware. For example, computer navigation is utilized
in hip replacement surgery to add precision to implant positioning
by providing data on functional parameters such as leg length and
offset changes during surgery.
[0007] Despite obvious clinical benefit, these systems have had
limited adoption due to their expense, the learning curve and
training requirements for surgeons and, for some systems, the
additional procedure and time associated with hardware insertion
into the patient. These adoption barriers have limited the use of
computer assisted navigation to an extremely small percentage of
overall hip arthroplasty surgeries. The surgeons that do not use
these systems are limited to traditional techniques that are
generally based on visual analysis and surgeon experience. However,
these techniques are inconsistent, often leading to outliers in
functional parameters which may affect patient satisfaction and
implant longevity.
[0008] Details of one such technique, specifically used in a
minimally invasive hip arthroplasty technique referred to as the
direct anterior approach, are mentioned in the description of a
total hip arthroplasty surgery, by Matta et al. in "Single-incision
Anterior Approach for Total hip Arthroplasty on an Orthopedic
Table", Clinical Ortho. And Related Res. 441, pp. 115-124 (2005).
The intra-operative technique described by Matta et al. is
time-consuming and has a high risk of inaccuracy due to differences
in rotation, magnification and/or scaling of various images. The
high risk of inaccurate interpretation using this technique has
limited its utility in guiding surgical decision making.
[0009] What appears to be a software implementation of this
technique is described by Penenberg et al. in U.S. Patent
Publication No. 2014/0378828, which is a continuation-in-part
application of U.S. Pat. No. 8,831,324 by Penenberg. While the use
of a computer system may facilitate some aspects of this technique,
the underlying challenges to the technique are consistent with the
challenges to Matta's approach, and limit the system's potential
utility.
[0010] There are various other examples of where intra-operative
guidance systems could improve quality of patient care in
orthopedics through the reduction of outliers. One such example is
in the treatment of peritrochanteric hip fractures. The selection
of the proper implant and associated neck-shaft angle is often
incompletely evaluated by the surgeon and implant representative
utilizing conventional techniques. Furthermore, variations in
placement of screws and other fixation devices and implants can
significantly alter patient outcomes in treatment of these
fractures. These variations and resulting outcomes are analyzed by
Baumgaertner et al. in "The Value of the Tip-Apex Distance in
Predicting Failure of Fixation of Peritrochanteric Fractures of the
Hip", J. Bone Joint Surg. 77-A No. 7, pp. 1058-1064 (1995). Other
techniques relating to femoral fractures, including measurement of
tip apex distance and screw position, are discussed by Bruijin et
al. in "Reliability of Predictors for Screw Cutout in
Intertrochanteric Hip Fractures", J. Bone Joint Surg. Am. 94, pp.
1266-72 (2012).
[0011] Proper reduction of fractures, that is, proper alignment of
bones during surgery, often leads to more consistent patient
outcomes, and intraoperative analysis of such reductions is
incompletely evaluated currently because of the lack of
non-invasive technologies that enable intraoperative analysis. One
example is in the treatment of distal radius fractures. As
referenced by Mann et al, "Radiographic evaluation of the wrist:
what does the hand surgeon want to know?" Radiology, 184(1), pp
15-24 (1992), accurate restoration of certain parameters, such as
radial inclination, radial length and Palmar Slope or Tilt, during
the treatment of distal radius fractures is important. Currently,
intraoperative images are utilized by surgeons, but there is no
ability to readily analyze these parameters and form comparative
analysis to normal anatomy.
[0012] Given the inherent scaling limitations of preoperative
surgical planning and adoption barriers of current intraoperative
computer navigation systems, an opportunity exists for a system and
method that provides accurate intraoperative guidance and data, but
without the barriers to adoption and invasive hardware requirements
of traditional computer-assisted navigation.
[0013] It is therefore desirable to have a system and method to
effectively scale and adjust images intra-operatively using
comparative anatomical features, to enhance patient quality of care
by providing accurate intra-operative guidance and data. However,
in view of the art considered as a whole at the time the present
invention was made, it was not obvious to those of ordinary skill
in the field of this invention how the shortcomings of the prior
art could be overcome.
[0014] All referenced publications are incorporated herein by
reference in their entirety. Furthermore, where a definition or use
of a term in a reference, which is incorporated by reference
herein, is inconsistent or contrary to the definition of that term
provided herein, the definition of that term provided herein
applies and the definition of that term in the reference does not
apply.
[0015] While certain aspects of conventional technologies have been
discussed to facilitate disclosure of the invention, Applicant in
no way disclaims these technical aspects, and it is contemplated
that the claimed invention may encompass one or more of the
conventional technical aspects discussed herein.
[0016] The present invention may address one or more of the
problems and deficiencies of the prior art discussed above.
However, it is contemplated that the invention may prove useful in
addressing other problems and deficiencies in a number of technical
areas. Therefore, the claimed invention should not necessarily be
construed as limited to addressing any of the particular problems
or deficiencies discussed herein.
[0017] In this specification, where a document, act or item of
knowledge is referred to or discussed, this reference or discussion
is not an admission that the document, act or item of knowledge or
any combination thereof was at the priority date, publicly
available, known to the public, part of common general knowledge,
or otherwise constitutes prior art under the applicable statutory
provisions; or is known to be relevant to an attempt to solve any
problem with which this specification is concerned.
SUMMARY OF THE INVENTION
[0018] An object of the present invention is to provide a system
and method to accurately and effectively scale, adjust and/or
perform calculations on images of anatomical features and/or
implants such as prosthetic devices during surgery.
[0019] Another object of the present invention is to provide image
analysis and feedback information to enable more accurate planning,
better fracture reduction, and/or optimal implant selection during
the surgery.
[0020] Yet another object of the present invention is to capture
and preserve a digital record of patient results for data
collection and quality improvements in surgical procedures.
[0021] A still further object of the present invention is to
improve the outcome of bone repositioning, fracture repair, and/or
fixation within a patient.
[0022] This invention results from the realization that
intraoperative scaling and other analysis of a primary image and at
least one secondary image can be more accurately accomplished based
on an object of known dimension which, along with at least two
points that are consistent in those images, can facilitate precise
scaling and other analysis of the secondary image in addition to
the primary image as needed. At least one of the primary image and
the secondary image is a results image taken during a surgical
procedure on a portion of a patient. Further, at least another of
the primary and secondary images is a reference image including (i)
a preoperative ipsilateral image and/or (ii) a contralateral image,
taken before or during surgery, of a comparable portion of the
patient.
[0023] This invention features a system to analyze images at a
surgical site within a patient, including an image selection module
to acquire (i) at least a first, reference image including one of a
preoperative image of the surgical site and a contralateral image
on an opposite side of the patient from the surgical site, and (ii)
at least a second, results image of the site. The system further
includes a data input module that receives the first and second
images and generates at least two points to establish a first
stationary base and a second stationary base on at least one
anatomical feature that is present in each of the first and second
images, respectively, and an analysis module that utilizes the
stationary base in each image to provide at least one of (a)
overlaying the first and second images and comparing at least one
of bone alignment, scaling and implant alignment within the images
and (b) analyzing at least one of image rotation, image alignment,
scaling, offset, abduction angle, length differential and
orientation of at least one of a bone and an implant within the
images.
[0024] In some embodiments, the first and second images are
provided by the image selection module to the data input module in
a digitized format. At least one dimension of each of the first and
second stationary bases is retrievably stored in at least one
storage medium as a count of pixels for that dimension, and the
analysis module utilizes the pixel count for that dimension. In
certain embodiments, the analysis module utilizes the stationary
base in a selected one of the first and second images to provide at
least relative scaling of the other of the first and second images
to the match the scaling of the selected one of the first and
second images. In one embodiment, the analysis module utilizes at
least one object of known dimension in at least one of the first
and second images to provide absolute scaling, that is, objective
scaling according to a measurement system, to at least that image.
In an embodiment, the analysis module rotates at least one of the
first and second images relative to the other of the first and
second images so that both images are aligned according to their
respective stationary bases.
[0025] In a number of embodiments, the data input module generates
at least one landmark point for each image that is spaced from the
stationary base in that image, and the analysis module utilizes the
landmark points to assist alignment of the first and second images
relative to each other. In other embodiments, the analysis module
utilizes the landmark points to position a digital template on at
least one of the first and second images. In certain embodiments,
the system further includes a template input module that provides
at least one digital template that is superimposed over at least
one feature in at least one of the first and second images. In some
embodiments, the at least one digital template is matched to at
least one feature in each of the first and second images. In one
embodiment, at least one digital template is matched to an implant
in the second, results image and then the digital template is
superimposed on the first, reference image to analyze at least one
parameter such as abduction angle, offset, and/or length
differential of at least one bone of the patient. Preferably, the
system further includes a display to provide at least visual
guidance to a user of the system.
[0026] In one embodiment, the first image is a contralateral image
that is flipped and overlaid on the second image and, in another
embodiment, the first image is a contralateral image, the data
input module generates a common stitching line in each image,
typically separate from the stationary base established in each
image, and the first and second images are stitched together to
form a unitary view of both sides of the patient. In some
embodiments, scaling or rescaling of at least one of the images is
accomplished by measuring a portion of an anatomical feature during
surgery, such as a femoral head, and comparing the measured feature
to an initial, preoperative image which includes that feature. In
other embodiments, scaling or rescaling is accomplished by
identifying at least one known dimension of an implant with an
intraoperative image including that implant and then scaling
according to that known dimension.
[0027] This invention further features a system and method for
analyzing images to optimize the restoration of orthopedic
functionality, while minimizing failures and patient discomfort, by
providing intraoperative comparison including calculations, scaling
and/or re-scaling for at least one operative, results image of a
site within a patient taken during surgery. The operative or
results image is compared with at least one reference image of (i)
a preoperative ipsilateral image and/or (ii) a contralateral image,
taken before or during surgery, of comparable portions of a
patient. At least one stationary base is selected in each image to
serve as a reference during the image comparisons and/or
scaling.
[0028] In certain embodiments, the system and method include
optimizing the sizing and placement of an implant at the site
within the patient. The step of analyzing includes estimating an
optimally-configured implant, and the method further includes
selecting a final implant based on the optimally-configured
implant. Certain embodiments further include generating an
estimated measurement of the first anatomical feature utilizing the
first image, and scaling the first image includes calculating a
difference between the estimated measurement and the direct
measurement. In some embodiments, an initial scaling is re-scaled
based on the direct measurement.
[0029] In a number of embodiments, the step of analyzing the
placement includes comparing the second image with the accurately
scaled first image on a mobile computing device. In one embodiment,
the step of analyzing includes comparing the first anatomical
feature with a corresponding contra-lateral anatomical feature of
the patient, such as a joint on the opposite side of the patient.
In certain embodiments, the first anatomical feature is located on
a portion of a bony part of the patient to be replaced, such as a
femoral head, and obtaining the direct measurement includes
excising the bony part from the patient, and measuring the first
anatomical feature substantially along the first viewing angle. In
some embodiments, a guidance system is provided to adjust the
viewing area of one image on a screen to track actions made by a
user to another image on the screen, such as to focus or zoom in on
selected landmarks in each image. In certain embodiments, at least
one of abduction angle and anteversion is calculated. In certain
embodiments, error analysis and/or correction is provided for at
least one image, such as providing a confidence score or other
normalized numeric error analysis, and/or a visual representation
of at least one error value or error factor, such as relative
alignment of one or more geometric shapes or symbols in two or more
images.
[0030] This invention also features a system and method for
analyzing images to optimize the restoration of orthopedic
functionality at a surgical site within a patient, including at
least one of capturing, acquiring, selecting and receiving to
provide: (i) at least a first, reference image along at least a
first viewing angle including one of a preoperative image of the
surgical site and a contralateral image on an opposite side of the
patient from the surgical site; and (ii) at least a second, results
image of the site along the first viewing angle after a surgical
procedure has been performed at the site. The system and method
further include generating on each of the first and second images
at least two points to establish a stationary base on a stable
portion of the surgical site and identifying at least one landmark
on another portion of the surgical site spaced from the stationary
base, and providing at least one of (a) an overlay of the first and
second images to enable comparison of at least one of bone and
implant alignment within the images, (b) matching of at least one
digital template to at least one feature in each of the first and
second images, and (c) a numerical analysis of at least one
difference between points of interest, such as at least one of
offset, length differential and orientation of at least one of a
bone and an implant within the images.
[0031] These and other important objects, advantages, and features
of the invention will become clear as this disclosure proceeds.
[0032] The invention accordingly comprises the features of
construction, combination of elements, and arrangement of parts
that will be exemplified in the disclosure set forth hereinafter
and the scope of the invention will be indicated in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] For a fuller understanding of the invention, reference
should be made to the following detailed description, taken in
connection with the accompanying drawings, in which:
[0034] FIG. 1 is a schematic image of a frontal, X-ray-type view of
a pelvic girdle of a patient illustrating various anatomical
features;
[0035] FIG. 1A is a schematic image viewable on a display screen by
a user of a system and method according to the present invention,
depicting a template image of a prosthesis superimposed over the
upper portion of a femur in an X-ray image of the hip region of a
patient;
[0036] FIG. 1B is an enlargement of the digital template image of
FIG. 1A;
[0037] FIG. 2 is an image rendering similar to FIG. 1A after the
digital template has been removed, illustrating measurement of a
portion of the femoral head utilizing a reference line;
[0038] FIG. 3 is an image similar to FIG. 1A after the digital
template has been re-scaled according to the present invention;
[0039] FIG. 4A is a schematic diagram of a system according to the
present invention that interfaces with a user;
[0040] FIG. 4B is a schematic diagram illustrating how multiple
types of user interfaces can be networked via a cloud-based system
with data and/or software located on a remote server;
[0041] FIG. 4C is a high-level schematic diagram of a system
according to the present invention;
[0042] FIG. 4D is a schematic diagram of the Intraoperative
Analysis Module in FIG. 4C;
[0043] FIG. 4E is a schematic diagram of several variations of the
Surgical Analysis Module in FIG. 4D;
[0044] FIG. 4F is a schematic diagram of the Intraoperative
Rescaling Module in FIG. 4C;
[0045] FIG. 4G is a schematic diagram of an alternative
Intraoperative Analysis System according to the present
invention;
[0046] FIG. 4H is a schematic diagram of an AP (Anterior-Posterior)
Pelvis Reconstruction System according to the present
invention;
[0047] FIG. 5 depicts Flowchart A for the operation of
Intraoperative Rescaling in one construction of the system and
method according to the present invention;
[0048] FIG. 6 depicts Flowchart B for an Anterior Approach for hip
surgery utilizing Flowcharts G and J;
[0049] FIG. 7 depicts Flowchart G showing technique flow for both
contralateral and ipsilateral analysis;
[0050] FIG. 8 depicts Flowchart W of several functions performed
for hip analysis;
[0051] FIG. 9 is an image of the right side of a patient's hip
prior to an operation and showing a marker placed on the greater
trochanter as a landmark or reference point;
[0052] FIG. 10 is an image similar to FIG. 9 showing a reference
line, drawn on (i) the pre-operative, ipsilateral femur or (ii) the
contra-lateral femur, to represent the longitudinal axis of the
femur;
[0053] FIG. 11 is an image similar to FIG. 10 with a line drawn
across the pelvic bone intersecting selected anatomical
features;
[0054] FIG. 12 is a schematic screen view of two images, the
left-hand image representing a pre-operative view similar to FIG.
10 and the right-hand image representing an intra-operative view
with a circle placed around the acetabular component of an implant
to enable rescaling of that image;
[0055] FIG. 13 is a schematic screen view similar to FIG. 12
indicating marking of the greater trochanter of the right-hand,
intra-operative image as a femoral landmark;
[0056] FIG. 14 is a schematic screen view similar to FIG. 13 with a
reference line drawn on the intra-operative femur in the right-hand
view;
[0057] FIG. 15 is an image similar to FIGS. 11 and 14 with a line
drawn across the obturator foramen in both pre- and intra-operative
views;
[0058] FIG. 16 is an overlay image showing the right-hand,
intra-operative image of FIG. 15 superimposed and aligned with the
left-hand, pre-operative image;
[0059] FIG. 17 represents a screen viewable by the user during a
surgical procedure guided according to the present invention;
[0060] FIG. 18 depicts Flowchart J of AP Pelvis Stitching and
Analysis;
[0061] FIG. 19 represents a screen view with a left-hand image of
the contra-lateral, left side of a patient having a line drawn on
the pubic symphysis;
[0062] FIG. 20 is a view similar to FIG. 19 plus a right-hand,
intra-operative image of the right side of the patient, also having
a line drawn on the pubic symphysis;
[0063] FIG. 21 shows the images of FIG. 20 overlaid and "stitched
together" to reconstruct a view of the entire hip region of the
patient
[0064] FIG. 22 is view similar to FIG. 21 with one reference line
drawn across the acetabular component of the image and another
reference line touching the lower portions of the pelvis
[0065] FIG. 23 depicts Flowchart L showing Intraoperative Guidance
for Intertrochanteric Reduction and Femoral Neck Fractures
according to another aspect of the present invention, referencing
Flowcharts M and N;
[0066] FIG. 24 depicts Flowchart M for Intertrochanteric Reduction
Guidance, referencing Flowchart P;
[0067] FIG. 25 depicts Flowchart P for processing a Contralateral
or Ipsilateral Image;
[0068] FIG. 26 is a representation of a screen view with a
left-hand image of the left, contralateral, "normal" side of a
patient's hip region inverted to resemble the right, "fractured"
side of the patient and showing marking of the lesser trochanter to
serve as a femoral reference point;
[0069] FIG. 27 is a view similar to FIG. 26 showing drawing of a
line across the obturator foramen for overlay reference;
[0070] FIG. 28 is a view similar to FIG. 27 showing measurement of
neck shaft angle;
[0071] FIG. 29 is a screen view with the left-hand image similar to
FIG. 28 and a right-hand image of the fractured side of the
patient, showing marking of the lesser trochanter on the fractured
side;
[0072] FIG. 30 is a view similar to FIG. 29 showing marking of the
obturator foramen of the fractured side;
[0073] FIG. 31 is a view similar to FIG. 30 showing measurement of
neck shaft angle on the fractured side;
[0074] FIG. 32 is a combined image showing the fractured side image
overlaid on the normal, inverted side image;
[0075] FIG. 33 depicts Flowchart N showing scaling and measurement
as referenced in Flowchart L;
[0076] FIG. 34 represents a screen view of an image of a screw
implanted to treat an inter-trochanteric hip fracture, showing
measurement of the screw;
[0077] FIG. 35 is a view similar to FIG. 34 showing measurement of
Tip-Apex distance in an AP image;
[0078] FIG. 36 is a view similar to FIG. 35 plus a lateral view on
the right-hand side of the screen, showing measurement of the
screw;
[0079] FIG. 37 is a view similar to FIG. 36 showing measurement of
Tip-Apex distance in the right-hand image;
[0080] FIG. 38 is a combined "Intertroch" view showing both
Tip-Apex Analysis and Neck Shaft Analysis;
[0081] FIG. 39 depicts Flowchart Q of Intraoperative Guidance for
Distal Radius Fracture Reduction according to another aspect of the
present invention, referencing Flowcharts R and S;
[0082] FIG. 40 depicts Flowchart R showing Radial Inclination and
Length Reduction Guidance, and referencing Flowchart T;
[0083] FIG. 41 depicts Flowchart S showing Palmar Slope Reduction
Guidance;
[0084] FIG. 42 depicts Flowchart T showing identification of
various anatomical features in the wrist and image processing;
[0085] FIG. 43 represents a screen view of an image of a "normal"
wrist of a patient with a line drawn on the radius to indicate its
central axis;
[0086] FIG. 44 is a view similar to FIG. 43 with marking of
selected anatomical points;
[0087] FIG. 45 is a view similar to FIG. 44 with a reference line
drawn across the carpal bones to provide a stationary base
reference;
[0088] FIG. 46 is a view of an image of the normal wrist rotated to
draw Palmar Tilt;
[0089] FIG. 47 is a screen view with the left-hand image similar to
FIG. 45 and a right-hand image of the fractured side of the
patient, showing marking of the central axis of the radius on the
fractured side;
[0090] FIG. 48 is a view similar to FIG. 47 showing marking of
anatomical points on the fractured side;
[0091] FIG. 49 is a view similar to FIG. 48 with a reference line
drawn across the carpal bones on the fractured side;
[0092] FIG. 50 is a screen view with the left-hand image similar to
FIG. 46 and a right-hand image of the fractured wrist rotated to
draw Palmar Tilt;
[0093] FIG. 51 is a combined view as a Distal Radius Report
according to the present invention;
[0094] FIG. 52 is an image similar to FIG. 15 with points marking
the lowest point on the ischial tuberosity and points marking the
obturator foramen and top of the pubic symphysis in both pre- and
intra-operative views;
[0095] FIG. 53 is an overlay image showing the right-hand,
intra-operative image of FIG. 52 superimposed and aligned with the
left-hand, pre-operative image utilizing triangular stable
bases;
[0096] FIG. 54 is a schematic combined block diagram and flow chart
of an identification guidance module utilized according to the
present invention;
[0097] FIG. 55 is a schematic block diagram of modules that analyze
the orientation of a component such as an acetabular cup to
generate abduction angle and anteversion information;
[0098] FIG. 56 is an image of an acetabular cup positioned in the
left acetabulum of a patient with a circle drawn around its
hemispherical surface to provide diameter information;
[0099] FIG. 57 is an image similar to that of FIG. 56 with a line
segment drawn under the cup to calculate abduction angle relative
to a neutral axis line;
[0100] FIG. 58 is an image similar to that of FIG. 57 with arcs
drawn at the bottom of the acetabular cup to assist calculation of
anteversion;
[0101] FIG. 59 depicts Flowchart X of abduction angle and
anteversion analysis by the modules of FIG. 55 relative to the
images of FIGS. 56-58
[0102] FIG. 60 is a schematic screen view of an image of the right
side of a patient's hip prior to an operation and showing a mark
placed on the greater trochanter as a landmark or reference point
according to the present invention;
[0103] FIG. 61 represents a screen viewable by the user during a
surgical procedure guided according to the present invention
showing two images, the left-hand image representing a
pre-operative view similar to FIG. 60 and the right-hand image
representing an intra-operative view with a circle placed around
the acetabular component of an implant to enable scaling or
rescaling of that image based on an object of known size;
[0104] FIG. 62 is a schematic screen view similar to FIG. 61
indicating marking of the lateral shoulder of the prosthesis of the
right-hand, intra-operative image, also with the greater trochanter
marked in both images as a femoral landmark;
[0105] FIG. 63 is a schematic screen view similar to FIG. 62 with a
reference box indicating an acetabular template generated on top of
the acetabular component of the prosthesis on the intra-operative
femur in the right-hand view;
[0106] FIG. 64 is a schematic screen view similar to FIG. 63 with
the acetabular template now rendered in a precise location across
the femoral head in the preoperative view, using intraoperative
data gathered during the step represented by FIG. 63;
[0107] FIG. 65 is a schematic screen view similar to FIG. 64
showing the acetabular component outline overlaid on the femoral
head on the left-hand, preoperative image with an overlay image of
the prosthesis superimposed and aligned with the femoral stem of
the prosthesis in the right-hand, intra-operative image;
[0108] FIG. 66 is a schematic screen view similar to FIG. 65
showing the femoral stem template placed on the pre-operative
image, utilizing intraoperative data gathered in the step
represented by FIG. 65, with intraoperative Offset and Leg Length
calculations;
[0109] FIG. 67 is a schematic diagram of an Intra-operative
Analysis Module according to the present invention to implement the
Templating Technique generating images as shown above in FIGS.
60-66;
[0110] FIGS. 68A and 68B depict Flowchart U showing Intraoperative
Templating Flow within the Module of FIG. 67;
[0111] FIG. 69 depicts Flowchart Y showing functions applied to the
pre-operative and intraoperative hip images for Intraoperative
Templating of Flowchart U; and
[0112] FIG. 70 is an image of a trial implant in a hip with the
acetabular component transacted by a stationary base line and with
two error analysis triangles.
DETAILED DESCRIPTION OF THE INVENTION
[0113] In the following detailed description of the preferred
embodiments, reference is made to the accompanying drawings, which
form a part thereof, and within which are shown by way of
illustration specific embodiments by which the invention may be
practiced. It is to be understood that other embodiments may be
utilized and structural changes may be made without departing from
the scope of the invention.
[0114] This invention may be accomplished by a system and method
that provides intraoperative guidance via analysis including at
least one of scaling, calculations, comparisons, and alignment for
operative images taken during surgery by comparing them with
preoperative ipsilateral images and/or contralateral images, taken
before or during surgery, of comparable portions of a patient. At
least one stationary base is selected in each image to serve as a
reference during the image analysis. Broadly, some techniques
according to the present invention, referred to by the present
inventors as "Image Overlay", place one image over another image
during analysis to generate a combined overlapped image, while
certain other techniques according to the present invention,
referred to by the present inventors as "Reverse Templating" or
"Templating Technique", place a digital template first on a
properly-scaled intra-operative image and then on a scaled
pre-operative image during analysis.
[0115] In general, accurate analysis of two images of a patient is
directly related not only to how similar the two images are, but
also how similarly the images are aligned with respect to scale,
rotation, and translation. Using conventional techniques, a user
would have to manually adjust the images and/or retake multiple
images to achieve this goal, something that would be difficult to
do reliably and accurately. Utilizing two or more points as a
stationary base according to the present invention in each image
enables accurate analysis of the two images. Furthermore, the
present Image Overlay technique can analyze how "similar" these
images are to give the user feedback as to how accurate the results
are, that is, to provide a confidence interval.
[0116] To obtain useful information, the images (the "intraop"
intra-operative image and a "preop" pre-operative image, for
example) must be scaled similarly and preferably rotated similarly.
If the scale is off, this will lead to error unless re-scaled
properly. If the rotation is off, the user is likely to spend
significant time "eyeballing" to manually align the digital
template on the preop image to match the intraop position during
Reverse Templating according to the present invention. Use of one
or more landmarks, such as the teardrop of the pelvis and/or the
greater trochanter of the femur for hip-related surgery, according
to the present invention aids in automated and accurate
superimposing of a template onto the preop image to match the
intraop position of an implant and superimposed digital template
during Reverse Templating. For example, the teardrop helps
accurately place the acetabular template and the greater trochanter
helps place the femoral template at the right level on each image.
As compared to the present Image Overlay technique, the present
Reverse Templating technique is less sensitive to how similar the
images are, and therefore has a wider breadth of use as images can
be taken in different settings, such as comparing a preop image
taken in a physician's office with an intraop image taken during
hip surgery involving a posterior approach or other surgical
procedure.
[0117] In some implementations, a system and method according to
the present invention analyzes images to provide guidance to
optimize the restoration of orthopedic functionality at a surgical
site within a patient, including capturing, selecting or receiving:
(i) at least a first, reference image along at least a first
viewing angle including one of a preoperative image of the surgical
site and a contralateral image on an opposite side of the patient
from the surgical site; and (ii) at least a second, results image
of the site, preferably also along the first viewing angle, after a
surgical procedure has been performed at the site. The system and
method further include generating on each of the first and second
images at least two points to establish a stationary base on a
stable portion of the surgical site and identifying at least one
landmark on another portion of the surgical site spaced from the
stationary base, and providing at least one of (a) an overlay of
the first and second images to enable comparison of at least one of
bone and implant alignment within the images, (b) matching of at
least one digital template to at least one feature in each of the
first and second images, and (b) a numerical analysis of at least
one difference between points of interest, such as an analysis of
at least one of offset, length differential and orientation of at
least one of a bone and an implant within the images.
[0118] Establishing at least three points for the stationary base,
such as described below in relation to FIG. 70, is especially
useful for determining rotational differences between images. One
or more points may be shared with points establishing a scaling
line. Preferably, at least one landmark is selected that is spaced
from the stationary base points to increase accuracy of overlaying
and/or comparing images.
[0119] In some constructions, scaling, which includes rescaling in
some implementations, of at least one of the images is accomplished
by measuring an anatomical feature during surgery, and comparing
the measured feature to an initial, preoperative image which
includes that feature. In other constructions, scaling or rescaling
is accomplished by comparing an intraoperative image with at least
one known dimension of (i) an implant feature, such as the diameter
of an acetabular cup or a screw, or (ii) a temporarily-positioned
object such as a ball marker or a tool such as a reamer. Typically,
scaling or rescaling is accomplished by establishing two points on
a feature, generating a line between the two points, and
determining the correct length for the line.
[0120] In certain constructions utilizing implants, especially
prostheses, the combination of accurately scaled templating,
together with an innovative approach of combining a software-driven
system according to the present invention with intra-operative
medical imaging such as digital X-ray images, dramatically improves
the accuracy of various surgeries, especially difficult-to-see
anterior approach surgery for total hip replacement. The present
invention enables a surgeon to compensate for unintended variations
such as how a reamer or other tool interacts with a bone during
preparation of the surgical site before or during insertion of the
implant. In some constructions, the surgeon or other user is able
to compare a pre-operative or intra-operative X-ray-type image of a
patient's anatomy with an initial intra-operative X-ray-type image
of a trial prosthesis, and deduce changes of offset and/or leg
length to help guide surgical decision making. This unique process
will greatly improve patient satisfaction by increasing the
accuracy of direct anterior surgery and other types of surgeries,
and greatly increase surgeon comfort in performing these
less-invasive procedures.
[0121] In some implementations, a system and method according to
the present invention includes an inventive alternative "Reverse
Templating" methodology for analyzing parameters such as abduction
angle, intraoperative leg length and offset changes using a
different application of the stationary base, intraoperative
scaling and anatomical landmark identification techniques. For
Reverse Templating implementations, the system and method combines
the use of intraoperative data, gathered from intraoperative image
analysis, with intraoperative templating on a preoperative
ipsilateral image. The method can be applied in a wider range of
hip arthroplasty surgeries because it is less sensitive to
inconsistencies in preoperative and intraoperative image
acquisition, allowing the user to apply this system and method
during arthroplasty in the lateral position (i.e. posterior
approach). This alternative system and method also enables a user
to precisely analyze, intraoperatively, how a potential change in
implant selection would affect parameters such as abduction angle,
offset and/or leg length. In this approach, described below in
relation to FIGS. 60-69, the user will analyze the preoperative
ipsilateral and intraoperative images `side by side`, without the
need to overlap the images themselves. The system will scale and
align these images relative to one another using at least
intraoperative data, and then analyze offset and leg length changes
by combining intraoperative data with a unique utilization of
digital prosthetic templates.
[0122] For image analysis according to the present invention,
preferably at least one stationary base and at least one anatomical
landmark are selected. The term "stationary base", also referred to
herein as a "stable base", means a collection of two or more
points, which may be depicted as a line or other geometric shape,
drawn on each of two or more images that includes at least one
anatomical feature that is present in the two or more images of a
region of a patient. For example, different images of a pelvic
girdle PG of a patient, FIG. 1, typically show one or both
obturator foramen OF and a central pubic symphysis PS, which the
present inventors have recognized as suitable reference points or
features for use as part of a stationary base according to the
present invention. Other useful anatomical features, especially to
serve as landmarks utilized according to the present invention,
include femoral neck FN and lesser trochanter LT, shown on right
femur F.sub.R, and femoral head FH and greater trochanter GT shown
on left femur F.sub.L, for example. Femoral head FH engages the
left acetabulum of the pelvic girdle PG. Also shown in FIG. 1 are
ischial tuberosities IT at the bottom of the ischium, a "tear drop"
TD relating to a bony ridge along the floor of the acetabular
fossa, and the anterior superior iliac spine ASIS and the anterior
inferior iliac spine AIIS of the ileum. As described below, carpal
bones serve as a stationary base in images for radial bone fixation
and other wrist-related procedures. In general, having a
"non-movable" anatomical feature associated with the trunk of a
patient is preferred for a stationary base, rather than a jointed
limb that can be positioned differently among two or more
images.
[0123] In general, a longer stationary base is preferred over a
shorter stationary base, because the longer base, especially if it
is a line, will contain more pixels in images thereof and will
increase accuracy of overlays and scaling according to the present
invention. However, the further the stationary base is from the
area of anatomical interest, the greater the risk of
parallax-induced error. For example, if the area of interest is the
hip joint, then the ideal stationary base will be near the hip. In
some procedures involving hip surgery, for example, a stationary
base line begins at the pubic symphysis PS, touches or intersects
at least a portion of an obturator foramen OF, and extends to (i)
the "tear drop" TD, or (ii) the anterior interior iliac spine AIIS.
Of course, only two points are needed to define a line, so only two
reliable anatomical features, or two locations on a single
anatomical feature, are needed to establish a stationary base
utilized according to the present invention. More complex,
non-linear stationary bases may utilize additional identifiable
points to establish such non-linear bases.
[0124] Additionally, at least one identifiable anatomic "landmark",
or a set of landmarks, is selected to be separate from the
stationary base; the one or more landmarks are utilized in certain
constructions to analyze the accuracy of the overlay process. This
additional "landmark" preferably is part of the stationary anatomy
being anatomically compared. For example, the inferior portion of
the ischial tuberosity IT can be identified as an additional
landmark. This landmark, in conjunction with the stationary base,
will depict any differences or errors in pelvic anatomy or the
overlay which will enable the physician to validate, or to have
more confidence in, the output of the present system.
[0125] The term "trial hip prosthetic" is utilized herein to
designate an initial implant selected by a surgeon as a first
medical device to insert at the surgical site, which is either the
right side or the left side of a patient's hip in this
construction. In some techniques, the trial prosthetic is selected
based on initial digital templating similar to the procedure
described below for FIGS. 1A-3, for example.
[0126] One technique for accomplishing the present invention is
described in relation to FIGS. 1A-3, which illustrate successive
views or "screenshots" visible to a user of a system and method
according to the present invention utilized for hip surgery. FIG.
1A is a schematic representation of a screen view 10 depicting a
digital template image 20 of a prosthesis superimposed over the
upper portion of a right femur F.sub.R. In some techniques a
digitized X-ray image of the hip region of a patient along a
frontal or anterior-to-posterior viewing angle is utilized for
screen view 10 and, in other techniques, a digital photograph
"secondary" image of a "primary" X-ray image of the hip region of a
patient along a frontal or anterior-to-posterior viewing angle is
utilized for screen view 10. In one construction, screen view 10 is
shown on a computer monitor and, in another construction, is shown
on the screen or viewing region of a tablet or other mobile
computing device, as described in more detail below. Dashed line SK
represents skin of the patient and provides an outline of soft
tissues for this viewing angle. Pelvic Girdle PG may also be
referred to as a pelvis or hip.
[0127] Ball marker BM represents a spherical metal reference object
of known dimension placed between right leg RL and left leg LL, as
traditionally utilized to scale many types of medical images
including X-ray images. Use of a ball marker or other
non-anatomical feature is optional in techniques according to the
present invention, as described in more detail below. In
particular, the present invention is useful for unplanned trauma
surgery, where direct measurement of an anatomical feature, such as
caliper measurements of an extracted femoral head during emergency
hip surgery, can be utilized by the present invention to
intraoperatively guide such surgery.
[0128] Template image 20 is shown in greater detail in FIG. 1B with
a body component 22 including a stem 24, a fastener recess 26, and
a support 28 with a trunion 29, and an acetabular component 30
carried by support 28. Dashed line 32 indicates the longitudinal
axis of support 28 and dashed line 34 indicates a longitudinal body
axis for template image 20 to be aligned relative to a longitudinal
axis of the femur F, as described in more detail below.
[0129] Additional icons and reference elements are provided in this
construction, such as a reference line delete icon 40 for line 41,
FIG. 1A, a template body delete icon 42 and an acetabular component
delete icon 44 for body component 22 and acetabular component 30,
FIG. 1B, respectively. One or more of these "virtual" items can be
removed or added to view 10 by a user as desired by highlighting,
touching or clicking the "soft keys" or "soft buttons" represented
by the icons. In certain embodiments, one or more of the icons 40,
42 and/or 44 serves as a toggle to provide "on-off" activation or
de-activation of that feature. Characters or other indicia 46, FIG.
1A, can be utilized to designate image number and other identifying
information. Other useful information 48 can be shown such as
Abduction Angle, Offset Changes and Leg Length Changes, as
discussed in more detail below.
[0130] Screen view 51, FIG. 2, is similar to view 10 of FIG. 1A
after the digital template 20 has been removed, illustrating
measurement of a portion of the femoral head FH of femur F.sub.R
utilizing a reference line 60. Four indicator squares 52, 54, 56
and 58, also referred to as reference squares, navigation handles,
or navigation points, are provided in this construction to guide a
user to draw the reference line 60 in the viewing plane of screen
view 51. In some constructions, a user touches one of the squares
52-58 with a finger or a mouse cursor, and utilizes the square,
such as by `dragging` it, to move a marker to a desired location.
This enables manipulation without blocking the location of
interest.
[0131] Characters 70 such as "New Femoral Head Width" invite a user
to enter a direct measurement into field 72, such as "50" to
represent an actual 50 mm caliper measurement for the dimension
represented by line 60, as described in more detail below. In this
example, an initial scaling of image 51 had generated an estimated
measurement of "45.6 mm" for line 60. Other functional "soft
buttons" are "Rescale" 74, "Retemplate" 76, "Cancel" 78 and "Done"
80. In other constructions, as described in more detail below,
intraoperative rescaling is conducted separately from a hip
replacement process, and the direct measurement value, if needed,
is utilized for intraoperative rescaling, for adjusting the
template size, for comparing drawn lines, and other uses.
[0132] Direct measurement of the femoral head, such as with
calipers, typically is conducted before a trial implant is
inserted. The femoral head measurement enables (i) re-scaling of
the preoperative template or (ii) accurate scaling for the first
time, especially where a preoperative template has not been
utilized. During overlay analysis, however, scaling is accomplished
in some constructions by measuring or looking up a dimension of an
implant, such as the radius or width of the acetabular component of
a hip prosthesis, for example.
[0133] FIG. 3 is an image of a view 90 similar to view 10 of FIG.
1A, along the same viewing angle, after the digital template 20 has
been re-scaled according to the present invention to a revised
template 20'. In this example, reference line 41 was 13.1 mm in
FIG. 1A, and reference line 41', FIG. 3, is now 14.3 mm as
calculated by the system after re-scaling based on the direct
measurement. Also, for revised information 48', the Offset Changes
are re-calculated to be "0.9 mm" and the Leg Length Changes are
recalculated to be "4.1 mm".
[0134] In one construction, the JointPoint Intraop.TM. system
utilizes an interpolation mapping approach with one or more
reference points or "landmarks" to achieve template auto-rescaling.
Certain important landmarks on an X-ray image, or on a photograph
of an X-ray image, are used to anchor each fragment of a template.
This is the basic model:
.SIGMA..sub.0.sup.mP.sub.i=.SIGMA..sub.0.sup.mf(p.sub.i) EQ. 1
[0135] In this model, m is the number of landmarks, P.sub.i is
landmark after interpolation mapping, and is the original landmark.
f(p.sub.i) is the mapping function for rescaling.
f .function. ( p i ) = p i - p 1 .times. i p 2 .times. i - p 3
.times. i EQ . .times. 2 ##EQU00001##
[0136] where P.sub.i1 and P.sub.i2 are two reference landmarks
automatically provided by program based on the size of x-ray
image.
p.sub.1i=.left brkt-bot.p.sub.i.times.ratio.right brkt-bot.
EQ.3
p.sub.2i=.left brkt-top.p.sub.i.times.ratio.right brkt-bot.
EQ.4
[0137] Where "ratio" is the comparison of size of a regulator in a
target x-ray image and a compared x-ray image. The regulator can be
a ball marker, or a user-defined line or circle such as a circle
drawn around an acetabular component.
ratio = size .times. .times. of .times. .times. target .times.
.times. regulator size .times. .times. of .times. .times. compared
.times. .times. regulator EQ . .times. 5 ##EQU00002##
[0138] By following the model indicated above, each of the template
fragments lands in the same position when the size of a template is
changed and, therefore, users avoid the need to replace templates
every time a rescaling happens. Correct template placement can also
be facilitated by storing coordinates of a particular location on
the femoral component of a template, such as the midpoint of the
top of the trunion 29 shown in FIG. 1B, for example.
[0139] In one implementation, a system 101 according to the present
invention, FIG. 4A, has a user interface 103, a processor 105, and
a communications module 107 that communicates with a remote server
and/or other devices via a cloud 109, which represents a
cloud-based computing system. User interface 103 includes a display
111, a user input module 113 and device input 115 such as (i) a
camera, to take a digital photo of a fluoroscopic imaging screen,
also referred to as a "fluoro" image, or of a printed or otherwise
fixed X-ray-type image, or (ii) a connection to a conventional
medical imaging system (not shown). Display 111 is a separate
computer monitor or screen in some constructions and, in other
constructions, is an integrated touch-screen device which
facilitates input of data or commands of a user to processor 105.
In some constructions, user input 113 includes a keyboard and a
mouse.
[0140] Processor 105 includes capability to handle input, module
119, to send and receive data, module 121, and to render analysis
and generate results, module 123. Two-way arrows 117 and 125
represent wired or integrated communications in some constructions
and, in other constructions, are wireless connections.
Communications module 107 has a send/upload module 127 and a
receive/download module 129 to facilitate communications between
processor 105 and cloud 109 via wired or wireless connections 125
and 131, respectively.
[0141] In some constructions, the present invention provides the
ability to accurately adjust implants and corresponding templates
intra-operatively by combining mobile-based templating
functionality, utilizing a mobile computing device such as a
tablet, a Google Glass.TM. device, a laptop or a smart phone
wirelessly interconnected with a main computing device, and a
unique scaling technique translating real life intra-operative
findings into selection of an optimally-configured implant for a
patient. Preferably, the system includes a mode that does not
require connection with a remote server, in the event of loss of
internet connectivity or other extended system failure.
[0142] FIG. 4B is a schematic diagram of system 141 according to
the present invention illustrating how multiple types of user
interfaces in mobile computing devices 143, 145, 147 and 149, as
well as laptop 151 and personal computer 153, can be networked via
a cloud 109 with a remote server 155 connected through web
services. Another useful mobile imaging and computing device is the
Google Glass wearable device. Data and/or software typically are
located on the server 155 and/or storage media 157.
[0143] Software to accomplish the techniques described herein is
located on a single computing device in some constructions and, in
other constructions such as system 141, FIG. 4B, is distributed
among a server 155 and one or more user interface devices which are
preferably portable or mobile.
[0144] A system 200 according to the present invention, FIG. 4C,
includes a User Input Module 202 with one or more data items that
are provided to a Scaling Module 204, a Templating Module 206, an
Intraoperative Analysis Module 208, and a Display 210. Although
Scaling Module 204 is illustrated and described as separate from
Intraoperative Module 208 in some constructions, both Modules 204
and 208 can be considered as forms of analysis conducted according
to the present invention utilizing a stationary base generated on
at least two images. Further, User Input can be considered as a
data input module that generates at least two points to establish a
stationary base on at least one anatomical feature that is present
in the images. In this construction, system 200 also includes a
storage media 212 which receives and/or provides data to Modules
204, 206, 208 and Display 210. Scaling Module 204 includes Standard
Preoperative Scaling unit 214, Intraoperative Scaling unit 216 and
Intraoperative Rescaling unit 218 in this construction and provides
data to Templating Module 206 and/or Display 210.
[0145] The Intraoperative Analysis Module 208 is illustrated in
more detail in FIG. 4D with an Image Selection Module 220, a Stable
Base Identification Module 222 which guides the selection of at
least one stationary base, and a Landmark Identification Module
224. Module 222 provides instructions to Overlay Module 226; Module
224 provides instructions to the Overlay Module 226 and/or to an
optional Longitudinal Axis Identification Module 228, shown in
phantom. When utilized, module 228 communicates with Differential
Analysis Module 230 which in turn communicates with Surgical
Analysis Module 232, shown in more detail in FIG. 4E. Overlay
Module 226 communicates with Surgical Analysis Module 232 either
directly or via Differential Analysis Module 230.
[0146] Also optional and present in some constructions in the
Intraoperative Analysis Module 208 is a Stable Base Error Analysis
Module 2100 that can provide outputs to Overlay Module 226 and/or
Differential Analysis Module 230. When utilized, the Stable Base
Error Analysis Module 2100 compares at least two images selected in
Image Selection Module 220, and analyzes error or differences
between the anatomic structures that contain the stationary base
points. The module 2100 provides visual and/or quantitative data of
image inconsistencies, such as shown in FIG. 70 below, providing
guidance of how much value to place in the output of Intraoperative
Analysis Module 208, FIGS. 4C and 4D. Within the module 2100, the
system automatically, or the user manually, identifies one or more
anatomic error reference points located within the anatomic
structure selected to contain the stationary base. At least one of
the error reference points, but preferably all of them, must be
separate from the points utilized to establish the stationary base.
The two images are scaled, rotated and transformed utilizing the
stationary base according to the present invention. Because the
error reference points identified in this module 2100 are separate
from the stationary base points used to align the images, but are
on the same non-movable anatomic structure, differences in error
reference point location between the two images allow for the
analysis within this module 2100. If the points seem extremely
close, the anatomic structures are likely to be positioned very
consistently between the two images being analyzed. If points are
further apart, such as shown and described in relation to FIG. 70
below, then there are likely to be imaging and/or anatomic
inconsistencies that may impact the data provided by the Analysis
Module 208.
[0147] FIG. 4E is a schematic diagram of several variations of the
Surgical Analysis Module 232, FIG. 4D, depending on the surgical
procedures to be guided according to the present invention. One or
more of the following modules are present in different
constructions according to the present invention: Hip Arthroplasty
Module 240, Intertrochanteric Reduction Analysis Module 242,
Femoral Neck Reduction Analysis Module 244 and/or Distal Radius
Fracture Reduction Analysis Module 246. In the illustrated
construction, the Hip Arthroplasty Module 240 includes at least one
of an Ipsilateral Analysis unit 250a, a Contralateral Analysis unit
252, an AP Pelvis Stitching and Analysis unit 254 and an
alternative Contralateral Analysis unit 256 which communicates with
an Image Flip unit 258 and an AP Pelvis Stitching and Analysis unit
260. In some constructions, Ipsilateral Analysis module 250a
optionally provides inputs to a Reverse Templating Module 250b,
shown in phantom. Hip Arthroplasty is described in more detail
below in relation to FIGS. 6-17, with AP Pelvis Stitching and
Analysis described in relation to FIGS. 18-22 below.
[0148] Intertrochanteric Reduction Analysis Module 242 includes a
Contralateral Analysis Module 270, a Neck Shaft Analysis unit 272
and a Tip Apex Analysis unit 274 in this construction. Femoral Neck
Reduction Analysis Module 244 includes a Contralateral Analysis
Module 276 in this construction. Intertrochanteric Reduction
Analysis and Femoral Neck Reduction Analysis are described in
combination with FIGS. 23-38 below.
[0149] Distal Radius Fracture Reduction Analysis Module 246
includes Contralateral Analysis Module 278 in this construction.
Distal Radius Fracture Reduction is described in relation to FIGS.
39-51 below.
[0150] Three aspects of the present invention are represented by
FIGS. 4F-4H for intraoperative rescaling, intraoperative analysis,
and AP Pelvis reconstruction, respectively. FIG. 4F is a schematic
diagram of the Intraoperative Rescaling Module 218, FIG. 4C, with
Image Input Module 210 which contains Templated Input Module 201a,
Direct Measurement Recording Module 203, Image Rescaling Module
205, and Template Object Re-rendering Module 207. A digital
representation of a prosthesis, referred to as a "template", is
provided to Template Input Module 201 in one construction and, in
another construction, is generated by that Module 201. The digital
template is provided to Direct Measurement Recording Module 203,
which also records a direct measurement such as the width of the
femoral head in one construction and, in another construction,
utilizes a known implant dimension such as the width of a screw or
the radius of the acetabular component of a hip prosthesis. The
Image Rescaling Module 205 calculates possible adjustments in
sizing that may be required. For example, if a first image of a hip
depicted a femoral head as having a width of 48 mm, but direct
measurement by calipers reveals that the true dimension is 50 mm,
then the 2 mm discrepancy represents a four percent difference or
deviation, and the first image is rescaled by four percent
accordingly.
[0151] In some constructions, Re-rendering Module 207 includes a
Prosthetic Placement Update Module 280 and/or, in certain
constructions, an Other Object Placement Update Module 282 to
re-render objects other than prostheses. Prosthetic Placement
Update Module typically utilizes coordinate information, referred
to herein as `centroid` information, that is stored in a database
and tells the system what reference point should remain stationary,
relative to the image, during the rescaling process. Optionally,
Intraoperative Rescaling Module 218 further includes a Stationary
Base Identification Module 2110 and a Secondary Image Rescaling
Module 2112, both shown in phantom, which can provide rescaling of
the secondary image to Templated Object Re-rendering Module 207.
These phantom modules facilitate the scaling of a second image
based on directly observable measurements in the first image, if
both images include a stationary base that identify the same
anatomic points. More specifically, the first image is scaled
directly via the Direct Measurement Recording Module 203, but this
scaling is then applied to the second image by using the length
ratios between the stable bases identified in Stationary Base
Identification Module 2110.
[0152] An alternative Intraoperative Analysis System 208', FIG. 4G,
includes an Image Capture Module 209, a User Data Input Module 211,
and an Analysis Module 213. Optional additional capabilities
include a Mathematical Correction Input Module 215 and an Error
Analysis Module 217 as described in more detail below. Image
Capture Module 209 preferably includes at least one of a Camera
Picture input 219 for receiving or otherwise acquiring at least one
photograph, a Radiographic Image input 221 for accessing a
radiographic image from storage media or other location, and an
Interface 223 which communicates with a fluoroscope or other
medical imaging device to capture, receive or otherwise acquire an
image in real time. At least one of inputs 219, 221 and/or 223
captures or otherwise acquires (i) at least one preoperative or
contralateral reference image and (ii) at least one intraoperative
or postoperative results image. The at least two images are
provided to User Input Data Module 211 which utilizes a Stable Base
Identification Module 225 to guide a user to select at least two
stable base points, such as points on a pelvis, to generate a
stable base on each image, and a Landmark Identification Module 227
to prompt the user to select a location spaced from and separate
from the stable base, such as a location on the greater trochanter,
on each image. Optionally, in certain constructions the Image
Capture Module 209 also provides the images to the Error Analysis
Module 217, which guides a user to select at least one point on the
bony anatomy which contains the stable base points, to be analyzed
for anatomical or imaging inconsistencies that could create error
in the Analysis Module 213. An example of the operation of Error
Analysis Module 217 is illustrated in FIG. 70 below, where the
difference between two overlaid triangles, representing sets of
three points in each image along the bony pelvis, is analyzed for
pelvic alignment inconsistencies. These images with selected
identifications are provided to the Analysis Module 213 which
utilizes at least one of the following modules in this
construction: Overlay Module 229 which utilizes visual analysis by
the user and/or an image recognition program; Mathematical Analysis
Module 231 which performs math calculations; or Other Analysis
Module 233 which utilizes different visual change criteria or
quantification analysis.
[0153] If anatomy of the patient being analyzed shifts or otherwise
moves between capture of the at least two images, then optional
Mathematical Correction Input Module 215 is beneficial to
compensate for such movement. Hip Analysis Correction Module 235 is
useful for hip surgery, such as by utilizing user identification of
the femoral longitudinal axis in each image, while Other
Mathematical Correction Modules 237 are utilized as appropriate for
other anatomical regions of a patient undergoing surgery or other
corrective treatment.
[0154] An alternative AP Pelvis Reconstruction System 260', FIG.
4H, utilizes Image Capture 239 to obtain an image of each side of a
patient, such as both sides of a hip, both shoulders, or two images
of other anatomy for which two locations are substantially
symmetrical or otherwise comparable. The at least two images are
provided to Image Scaling Module 241 and Image Stitching Location
Capture Module 243, which identifies corresponding locations such
as the tip of the pubic symphysis in each image. After scaling and
location identification by Modules 241 and 243, the images updated
with that information are provided to Image Stitching Module 245
which generates an overlay as described in more detail below.
[0155] Optional modules include Contralateral Image Flipping Module
247 which reverses one of the images before it is provided directly
to Image Stitching Module 245, or is provided indirectly via one or
both of Image Scaling Module 241 and/or Image Stitching Location
Capture Module 243. The output of a larger, stitched, overlay-type
image from Image Stitching Module 245 can be provided directly to
an AP Pelvis Analysis Module 251 or via an Image Cropping Module
249 to adjust the viewing area of the stitched image. In this
construction, Analysis Module 251 includes one or more of Leg
Length Analysis Module 253, Acetabular Cup Angle Analysis Module
255, and Other AP Pelvis Analysis Modules.
[0156] Flowchart A, FIG. 5, depicts the operation of Intraoperative
Rescaling in one construction of the system and method according to
the present invention related to hip surgery. The operation is
initiated, as represented by "Start" in step 300, and the femoral
head is extracted and measured using calipers, step 302. The
technique proceeds to step 304, and a line is drawn in software
corresponding to femoral head measurement such as illustrated in
FIG. 2 above. The caliper measurement is recorded, step 306, FIG.
5, and the system calculates intraoperative rescaling from directly
measured information, step 308. The system applies rescaling to the
selected image, step 310, and, in one construction, uses prosthetic
centroid information and rescaling data to update location of the
prosthesis on the image. More generally, the system utilizes at
least one selected point, such as the mid-point of the trunion,
that is associated with the prosthetic template to identify where
the prosthesis should remain stationary on the rescaled image. The
system rescales and redraws all other objects on the image, step
314, and rescaling is concluded, step 316.
[0157] Flowchart B, FIG. 6, illustrates an Anterior Approach for
hip surgery utilizing Flowcharts G and J. This technique is
commenced, step 320, and the decision whether to conduct
ipsilateral analysis is made, step 322. If yes, Flowchart G is
initiated, step 324; if no, then a decision is made whether to
conduct Contralateral analysis, step 326. If yes, then Flowchart G
is utilized, step 328, after which it is decided whether to create
and analyze stitched AP Pelvis, step 330. If yes, then Flowchart J
is activated. The Anterior Approach is concluded, step 334.
[0158] Flowchart G, FIG. 7, shows technique flow for both
contralateral and ipsilateral analysis. This technique is
commenced, step 340, and either contralateral or ipsilateral
analysis is selected, step 342. For contralateral analysis, the
contralateral hip image is captured, step 344, and the image is
flipped, step 346. For ipsilateral analysis, the preoperative
ipsilateral hip image is opened, step 348. For both types of
analysis, Flowchart W is applied, step 350.
[0159] Flowchart W, FIG. 8, after being activated by step 350, FIG.
7, guides a user to identify a femoral landmark such as the greater
trochanter in step 370, FIG. 8, and then the femoral axis is
identified, step 372. These steps are illustrated in FIGS. 9 and
10, below. A line is then drawn across the bony pelvis, step 374,
as shown in FIG. 11.
[0160] The technique proceeds to capturing an operative hip image,
step 352, FIG. 7, and identifying an acetabular component, step
354, such as shown in FIG. 12 below. Acetabular components are also
shown in and discussed relative to FIGS. 52-53 and FIGS. 55-59
below. The image is scaled by entering the size of the acetabular
component, step 356, and Flowchart W is then applied to the
operative hip, step 358. The operative and comparative hip images
are scaled by a stationary base generated by selecting at least two
reference points on the bony pelvis, step 360, such as shown in
FIG. 15. The scaled images are then overlaid in step 362 using the
bony pelvis points, such as the overlaid lines 386 and 412 shown in
FIG. 16. Differences in offset and leg length are calculated, step
364, and the technique is terminated, step 366, returning to step
326, FIG. 6, for ipsilateral comparison or to step 330 for
contralateral comparison.
[0161] Leg displacement is calculated in the pre-operation and
post-operation (intra-operation) to give users a visualization of
the operation process. The following steps 1-6 with Equations 6-10
are utilized in one construction:
[0162] 1. Draw a landmark, such as a single point or dot to
represent a feature such as the greater trochanter, and a
"stationary base" generated by selecting at least two points on the
bony pelvis in each of the pre-op image and post-op x-ray
image.
[0163] 2. One procedure for aligning two images utilizing
corresponding stationary bases, each base comprised of precisely
two points that define a line, is accomplished by the following
approach. Based on the positions of zero coordinate in each x-ray
image, translate the line segment position into screen coordinate
system. P.sub.original is the point's coordinate on each image's
coordinate plane. Z.sub.screen is the coordinate of zero in each
image on the screen coordinate plane.
P.sub.screen=P.sub.original+Z.sub.screen EQ. 6
[0164] 3. Find the rotation angle .theta. between the two line
segment line.sub.postop and line.sub.preop are the line vector of
each line segment.
.theta. = cos - 1 .times. ( line postop , line preop ) line preop
.times. line preop EQ . .times. 7 ##EQU00003##
[0165] 4. Calculate the rotation matrix R and apply it to the
landmark in pre-op image. lm.sub.preop is the center point position
of landmark, lm'.sub.preop is the center point position of landmark
after rotation.
R = ( cos .times. .times. .theta. sin .times. .times. .theta. sin
.times. .times. .theta. - cos .times. .times. .theta. ) .times.
.times. im preop ' = R * im preop EQ . .times. 8 ##EQU00004##
[0166] 5. Calculate the length ratio 5 between the two line
segments and scale the pre-op image based on it to get the landmark
position after scaling. Use of more than two points for a
stationary base benefits from a `best fit model` approach, such as
an algorithm that minimizes the distance between respective points
in each of the images.
S=length.sub.postop/length.sub.preop
lm''.sub.preop=*lm'.sub.preop EQ. 9
[0167] 6. Finally, calculate the distance of the two landmark in
both horizontal and vertical direction, visualize the results along
with the two overlaid x-ray images.
{offset,leg length}=lm.sub.postop-lm''.sub.preop EQ. 10
[0168] A currently preferred implementation of the JointPoint
IntraOp.TM. Anterior system, which provides the basis for
intraoperative analysis of the anterior approach to hip surgery, is
illustrated in relation to FIGS. 9-22. FIG. 9 is an image 376 of
the right side of a patient's hip prior to an operation and showing
a marker 378, bracketed by reference squares 377 and 379, placed by
a user as guided by the system, or placed automatically via image
recognition, on the greater trochanter as a landmark or reference
point, such as indicated in box 224, FIG. 4D and in box 227, FIG.
4G, for the Landmark Identification Module of systems 208 and 208',
respectively. FIG. 10 is an image 376' similar to FIG. 9 showing a
reference line 380, bracketed by reference squares 381, 382, 383
and 384, drawn on (i) the pre-operative, ipsilateral femur or (ii)
the contra-lateral femur, to represent the longitudinal axis of the
femur. FIG. 11 is an image 376'' similar to FIG. 10 with a line
386, defined by two end-points, which is drawn across the pelvic
bone intersecting selected anatomical features.
[0169] FIG. 12 is a schematic screen view of two images, the
left-hand image 376' representing a pre-operative view similar to
FIG. 10 and the right-hand image 390 representing an
intra-operative view with a circle 392 placed around the acetabular
component 394 of an implant 398 to enable rescaling of that image.
In some constructions, circle 392 is placed by an image recognition
program and then manually adjusted by a user as desired. Reference
square 398 designates implant 398 to the user. FIG. 13 is a
schematic screen view similar to FIG. 12 indicating marking of the
greater trochanter of the right-hand, intra-operative image 390' as
a femoral landmark 400, guided by reference squares 402 and 404.
FIG. 14 is a schematic screen view similar to FIG. 13 with a
reference line 406 drawn on the intra-operative femur in the
right-hand view 390'', guided by reference squares 407, 408, 409
and 410.
[0170] FIG. 15 is an image similar to FIGS. 11 and 14 with a line
386, 412 drawn across the obturator foremen in both pre- and
intra-operative views 376'' and 390''', respectively. Reference
squares 413, 414, 415 and 416 guide the user while drawing
reference line 412.
[0171] FIG. 16 is an overlay image showing the right-hand,
intra-operative, PostOp image 390''' of FIG. 15 superimposed and
aligned with the left-hand, pre-operative PreOp image 376''. In
this construction, soft button icons for selectively changing PreOp
image 376'' and/or PostOp image 390''' are provided at the lower
left-hand portion of the screen.
[0172] In another construction, more than two points are generated
for the stationary base for each image, such as illustrated in FIG.
52 for a preoperative image 1200 and a postoperative image 1201,
and in FIG. 53 for a combined overlay image 1298 of the
preoperative image 1200 and the postoperative image 1201 of FIG.
52. Similar locations on the pelvis in each image are selected to
generate the points utilized to establish a stationary base for
each image. In image 1200, for example, a first point 1202 is
generated on an upper corner of the obturator foramen or at the
pelvic tear drop, a second point 1204 is generated at the top or
superior portion of the pubic symphysis, and a third point 1206 is
generated at the lowest or inferior point on the ischial
tuberosity. Lines 1208, 1210 and 1212 are drawn connecting those
points to generate a visible stationary base triangle 1216 on image
1200. Also shown is a point 1214 on the greater trochanter. In
postoperative image 1201, first and second points 1203 and 1205
correspond with first and second points 1202 and 1204 in image
1200. A third point 1207 is shown in image 1201 between reference
squares 1209 and 1211 in the process of a user selecting the lowest
point on the ischial tuberosity to correspond with third point 1206
in image 1200. The user is prompted by "Mark lowest point on
Ischial Tuberosity" in the upper portion of image 1201. Also shown
is a circle 1213 around the acetabular component and a point 1215
on the greater trochanter.
[0173] Establishing at least three points is especially useful for
determining rotational differences between images. Overlay image
1298, FIG. 53, shows the three points 1202, 1204 and 1206 of preop
image 1200, forming the visible preop stationary base triangle
1216, which is positioned relative to the corresponding three
points 1203, 1205 and 1207 of postop image 1201, forming a visible
postop stationary base triangle 1311 overlaid relative to triangle
1216 in FIG. 53. A `best fit overlay` can be created using these
points by identifying the centroid of the polygon created by these
point, and rotating the set of point relative to one another to
minimize the summation of distance between each of the related
points. In this construction, scaling of the two images may be
performed by these same set of points or, alternatively, a separate
set of two or more points may be utilized to scale the two images
relative to each other. Clicking on a PreOp soft-button icon 1300
and a PostOp icon 1301 enable a user to alter positioning of images
1200 and 1201, respectively, within image 1298 in a
toggle-switch-type manner to selectively activate or de-activate
manipulation of the selected feature. One or more points of a
stationary base may be shared with points establishing a scaling
line. Preferably, at least one landmark is selected that is spaced
from the stationary base points to increase accuracy of overlaying
and/or comparing images.
[0174] Also illustrated in FIG. 53 are "Offset and Leg Length
Changes" with "Leg Length: -0.2 mm", "Offset: 21.8 mm" and
"Confidence Score: 8.1". A confidence ratio that describes the
quality of fit can be created by comparing the overlay area of the
two triangles relative to the size of the overall polygon formed by
the two triangles, including the non-overlapping areas of each
triangle. Abduction angle and anteversion calculations are
described below in relation to FIGS. 55-59.
[0175] A screen 420 viewable by a user during a surgical procedure
guided by a JointPoint.TM. IntraOp Anterior.TM. system according to
the present invention is represented by FIG. 17. The user selects
OVERLAY-IPSILATERAL HIP 422 or OVERLAY-CONTRALATERAL HIP 424 with
the option to use an existing overlay. The operative hip side to be
"replaced" is selected, via window 426, to confirm which will be
the operative side and the comparative side; the comparative side
is the same side as the operative side when a prior ipsilateral
image is chosen. Another option for the user is to select AP
(Anterior-Posterior) Pelvis simulation, step 425; in another
construction, AP Pelvis is presented to a user at a later stage
within Contralateral Hip overlay creation.
[0176] Flowchart J, FIG. 18, presents one technique according to
the present invention for AP Pelvis Stitching and Analysis. The
technique is commenced, step 500, and a contralateral image is
flipped to its original orientation, step 502. A stitching line is
drawn in the operative image, step 504, such as a line 516 on the
pubic symphysis shown in FIG. 19 for image 515, guided by reference
squares 517, 518, 519 and 520. A similar line is drawn on the
contralateral image, step 506, such as shown by line 522 in FIG. 20
for image 521, guided by reference squares 523, 524, 525 and 526.
The images are stitched, step 508, to simulate an AP Pelvis image
as shown in FIG. 21 with overlapped stitching lines 516 and 522,
with optional user adjustment by touching movement control icon
527, also referred to as a "rotation handle". The images are
cropped, step 510, and the simulated AP Pelvis is utilized for
intraoperative analysis, step 512, such as leg length analysis or
acetabular cobb angle. The technique terminates, step 514, and
returns to step 334, FIG. 6, in one construction.
[0177] FIG. 22 is view similar to FIG. 21 with one reference line
530 drawn across the acetabular component of the image 521', as
guided by reference squares 531, 532, 533 and 534, and another
reference line 536, as guided by reference squares 537, 538, 539
and 540, touching the lower portions of the pelvis to enable
accurate stitching for intraoperative analysis, including
acetabular component cobb angle determination, according to the
present invention. Additional analysis of the acetabular component,
such as anteversion or other alterations of position, orientation
or size, can be utilized as well.
[0178] Flowchart L, FIG. 23, illustrates Intraoperative Guidance
for Intertrochanteric Reduction and Femoral Neck Fractures
according to another aspect of the present invention, referencing
Flowcharts M and N. The technique begins, step 600, and reduction
guidance is considered, step 602. If selected, then the procedure
outlined in Flowchart M is initiated, step 604. Otherwise, or after
the Flowchart M procedure has been completed, the technique
proceeds to step 606 where the type of surgical procedure is
selected. In this construction, for Femoral Neck Fracture
Reduction, the technique proceeds to step 612 to generate a report
and store data for future reference. If Intertrochanteric Reduction
is selected, then guidance for Apex-Tip calculation is considered.
If selected, then the procedure described by Flowchart N is
followed, step 610. Otherwise, or after the Flowchart N procedure
has been completed, the technique proceeds to step 612 where a
report is generated and data stored as mentioned above. Guidance
for those procedures then ends, step 614.
[0179] Flowchart M, FIG. 24, for Intertrochanteric Reduction
Guidance, commences at step 620 when selected and the technique
proceeds to step 622 where a contralateral hip image is taken and
then flipped, step 624, to achieve a screen view such as
illustrated in FIG. 26. The inverted contralateral image is then
processed as outlined in Flowchart P as described below. The
surgeon then reduces the hip fracture, step 628, and the user of
this Guidance takes an X-ray-type image of the operative hip,
indicated in step 630 as "User takes ipsilateral hip fluoro". That
image is then processed by the procedure of Flowchart P, step 632,
and the contralateral and ipsilateral images are overlaid, step
634, such as shown in FIG. 32.
[0180] The overlay and neck shaft angles are analyzed in step 636,
FIG. 24 and, if not acceptable, the procedure returns to step 628
for another round of fracture reduction and analysis. Once
acceptable, the procedure of Flowchart M is ended, step 638, and
the technique returns to step 606, FIG. 23 as discussed above.
[0181] Flowchart P, FIG. 25, for processing a Contralateral or
Ipsilateral Image, begins at step 640 and then at least one femoral
landmark is identified, step 642, such as marking the lesser
trochanter with mark 660 as shown in FIG. 26 for an inverted image
661 of the normal, un-injured contralateral side of the patient. A
stationary base reference, preferably established by at least two
points, such as for line 662, is drawn on the pelvis, step 644,
FIG. 25, as shown in FIG. 27 for image 661'. The neck shaft angle
663 is measured, step 646, as shown in FIG. 28 as 138 degrees for
image 661''. Typically, this step 646, FIG. 25, includes
identifying the longitudinal axis 664 of the femur, FIG. 28,
because the femoral line 664 serves as one "leg" of the angle 663
to be measured, with the other leg 666 established by the
longitudinal axis of the femoral head. In some constructions, the
femoral line 664 provides an important reference relative to the
stationary base 662 so that the present system and method can
compensate for any difference in leg positions between images. It
is not unusual for a leg to shift its orientation by 5 degrees to
15 degrees even when the leg is held in traction.
[0182] If scaling is desired, step 648, FIG. 25, then it is
considered whether a scaling object is present in the image, step
650. If yes, then the scaling object is identified, step 652, and
the object size is entered, step 654. After those steps 652-654 are
completed, or if no scaling object is found in step 650, the
technique proceeds to the optional step of drawing a femoral line,
step 656 shown in phantom, if additional analysis is desired beyond
measuring the neck shaft angle in step 646 as described above. In
any event, after the procedure of Flowchart P is completed, step
658, the technique returns to step 628 or step 634, FIG. 24, in
this construction.
[0183] FIG. 29 is a screen view with the left-hand image 661''
similar to FIG. 28 and a right-hand image 670 of the fractured side
of the patient, showing marking of the lesser trochanter on the
fractured side with a mark 672. FIG. 30 is a view similar to FIG.
29 showing marking of the obturator foramen of the fractured side
with stable base line 674 in image 670'. FIG. 31 is a view similar
to FIG. 30 showing measurement of neck shaft angle of 123 degrees
on the fractured side as determined by measuring angle 676 between
femoral axis 678 and femoral head axis 679. FIG. 32 is a combined
image showing the fractured side image 670'' overlaid on the
normal, inverted side image 661''. Stable base lines 662 and 674
are overlapped exactly in this construction.
[0184] Flowchart N, FIG. 33, shows scaling and measurement for APEX
TIP calculation as referenced in Flowchart L, step 610, FIG. 23.
The technique begins, step 700, and a fixation screw is inserted,
step 702. An AP (Anterior-Posterior) X-ray-type photo is taken,
step 704, and the AP image is scaled, step 706, by measuring the
length or width of the screw as shown in FIG. 34 or by measuring
another object of known size. The Tip-Apex distance is measured,
step 708, such as shown in FIG. 35. A lateral X-ray-type image is
taken, step 710, and the lateral image is scaled, step 712, by
measuring the screw as shown in the right-hand image of FIG. 36;
alternatively, another object of known size is measured in the
image and compared to the known measurement. The Tip-Apex distance
is measured, step 714, in the lateral image such as shown in FIG.
37. AP and lateral Tip-Apex distances are calculated, step 716, and
the results are displayed such as shown in FIG. 38. If the
measurement is not satisfactory, step 718, then the technique
returns in one construction to step 704 where replacement
x-ray-type photos are taken and reanalyzed. Alternatively, or if
re-analysis still does not reveal acceptable measurements, the
surgeon repositions the screw as an alternative to step 702, and
then the guidance resumes with step 704. Once acceptable, the
procedure concludes, step 720, and the technique returns to step
612, FIG. 23.
[0185] FIG. 34 represents a screen view 730 of an image of a screw
732 implanted through an implant 734 to treat an intertrochanteric
hip fracture, showing measurement of the screw 732 with a
longitudinal axis or length line 736, guided by reference squares
737, 738, 739 and 740 generated by the present system in this
construction. FIG. 35 is a view 730' similar to FIG. 34 showing
measurement of Tip-Apex distance 742 of 8.2 mm, guided by reference
squares 743, 744, 745 and 746. FIG. 36 is a view 730' similar to
FIG. 35 plus a lateral view 750 on the right-hand side of the
screen, showing measurement of the width of the screw 732 with line
752, guided by reference squares 753, 754, 755 and 756. FIG. 37 is
a view similar to FIG. 36 showing measurement of Tip-Apex distance
in the right-hand image 750' with a Tip-Apex line 762 of 3.6 mm,
guided by reference squares 763, 764, 765 and 766. FIG. 38 is a
combined "Intertroch" view 770 showing both Tip-Apex Analysis and
Neck Shaft Analysis. The Lateral Tip Apex measurement of 3.6 mm
from view 750' is added to the AP Tip Apex measurement of 8.2 mm
from view 730' to calculate a Combined Distance of 11.8 mm in this
example. An overlay 780 of normal view 782 and fractured view 784
enables visual comparison, as well as image recognition and
analysis, to calculate a Fractured Neck Shaft Angle of 123 degrees
and a Normal Neck Shaft Angle of 133 degrees.
[0186] Guidance according to the present invention can be provided
for other anatomical regions such as wrists-hands, ankles-feet, and
spinal anatomy. Flowchart Q, FIG. 39, provides Intraoperative
Guidance for Distal Radius Fracture Reduction in wrists according
to another aspect of the present invention, referencing Flowcharts
R and S. This procedure begins, step 800, and a choice is made
whether to use radial inclination and length for reduction
guidance, step 802. If yes, the procedure outlined in Flowchart R
is followed, step 804. Once completed, or if those features are not
selected at step 802, then use of Palmar slope for reduction
guidance is considered at step 806. If selected, the procedure
summarized by Flowchart S is followed, step 808. After completion,
or if Palmar slope is not selected at step 806, then a report is
generated and data stored, step 810. If the radial fracture
reduction is not satisfactory, additional reduction is performed on
the affected wrist, step 814, and the technique returns to step
802. Once satisfactory, the procedure ends, step 816.
[0187] Flowchart R, FIG. 40, illustrates Radial Inclination and
Length Reduction Guidance. An AP (Anterior-Posterior) image of the
contralateral wrist is captured, step 822, and the contralateral
image is flipped or inverted, step 824. The flipped contralateral
image is processed utilizing the procedure outlined in Flowchart T,
step 826, and an AP image is captured, step 828, for the affected
wrist on which surgery is to be performed. The affected wrist image
is processed utilizing the Flowchart T procedure, step 830, and the
images are scaled and overlaid, step 832, such as illustrated in
FIG. 51. The affected and contralateral wrist radial inclination
angles are calculated for comparison, step 836, and a decision
whether to scale the images is made, step 838. If yes, the affected
and contralateral wrist radial lengths are calculated for
comparison, step 840. After such calculations, or if not selected,
the procedure ends, step 842, and the technique returns to step
806, FIG. 39.
[0188] Flowchart S, FIG. 41, depicts Palmar Slope Reduction
Guidance. This procedure begins, step 850, and an image of the
contralateral, normal wrist is captured, step 852. The Palmar slope
or tilt is measured, step 854, such as shown in FIG. 46. A lateral
image of the affected wrist is captured, step 856, and the Palmar
slope of the affected wrist is measured, step 858, such as shown in
FIG. 50. Data and images for the affected and contralateral wrist
are displayed, step 860, such as shown in FIG. 51. The procedure
ends, step 862, and the technique returns to step 810, FIG. 39.
[0189] Flowchart T, FIG. 42, shows identification of various
anatomical features in the wrist and image processing. It
commences, step 870, and a radial styloid is identified, step 872,
such as shown in FIG. 44. The ulnar styloid is identified, step
874, and the ulnar articular surface of the radius is identified,
step 876. The longitudinal axis of the radius is identified, step
878, such as shown in FIGS. 43 and 47 for the normal and affected
images, respectively.
[0190] A stationary base reference line is drawn across the carpal
bones in this construction, step 880, such as shown in FIG. 45. The
radial inclination is calculated, step 882. If the image is to be
scaled, step 884, then at least one scaling object is identified,
step 886, and the object size is entered, step 888. Intraoperative
scaling is applied to the image, step 890, and radial length is
calculated, step 892. Once completed, or if scaling is not desired,
the procedure ends, step 894, and the technique returns to steps
828 or 832 of FIG. 40 as appropriate.
[0191] FIG. 43 represents a screen view of an image 900 of a
"normal" wrist of a patient with a line 900 drawn on the radius to
indicate its central axis, guided by reference squares 904, 906,
908 and 910. FIG. 44 is a view 900' similar to FIG. 43 with marking
of selected anatomical points: Radial Styloid 912, guided by
reference squares 914 and 916; Ulnar Border of Radius 918, guided
by reference squares 920 and 922; and Ulnar Styloid 924, guided by
reference squares 926 and 928. FIG. 45 is a view 900'' similar to
FIG. 44 with a reference line 930 drawn across the carpal bones to
provide a stationary base reference, as guided by reference squares
932, 934, 936 and 938.
[0192] FIG. 46 is a view of an image 940 of the normal wrist
rotated to draw Palmar Tilt with longitudinal reference line 942,
guided by reference squares 944 and 946, and lateral reference line
948, guided by reference squares 950, 952, 954 and 956, with a
calculated Tilt of 7 degrees in this example.
[0193] FIG. 47 is a screen view with the left-hand image 900''
similar to FIG. 45 and a right-hand image 960 of the fractured side
of the patient, showing marking of the central axis 962 of the
radius on the fractured side, guided by reference squares 964, 966,
968 and 970. FIG. 48 includes a screen view image 960' similar to
image 960, FIG. 47, showing marking of anatomical points on the
fractured side: Radial Styloid 972, guided by reference squares 974
and 976; Ulnar Border of Radius 982, guided by squares 984 and 986;
and Ulnar Styloid 992, guided by squares 994 and 996. FIG. 49 is a
view 960'' similar to FIG. 48 with a reference line 1000 drawn
across the carpal bones on the fractured side, guided by reference
squares 1002, 1004, 1006 and 1008. In this constructions, a user
touches one of the squares with a finger or a mouse cursor, and
utilizes the square, such as by `dragging` it, to move a marker to
a desired location. This enables manipulation without blocking the
location of interest.
[0194] FIG. 50 is a screen view with the left-hand image 940'
similar to FIG. 46 and a right-hand image 1010 of the fractured
wrist rotated to draw Palmar Tilt with longitudinal reference line
1012, guided by reference squares 1014 and 1016, and lateral
reference line 1020, guided by reference squares 1022, 1024, 1026
and 1028, with a calculated Tilt of 3 degrees in this example. FIG.
51 is a combined view as a Distal Radius Report according to the
present invention, after the fractured side has been reduced, that
is, after a surgical operation has been performed on the fractured
side. The "Normal" image is an inverted contralateral image of the
opposite wrist-bones of the patient. Although not illustrated, one
or more plates or other implants may be utilized before and/or
after analysis according to the present invention to reduce
fractures as part of the surgical procedures to restore orthopaedic
functionality at the surgical site. Upper-left Image 1030 is an AP
Overlay of Radial Inclination to analyze radial bone fracture
reduction with specific regard to angle in AP orientation.
Contralateral or `Normal` Radial Inclination is 2.4 degrees in this
example and the Fractured Radial Inclination is 10.5 degrees.
Radial inclination reference lines for the normal wrist-bones are
shown in dashed lines while reference lines for the fractured
wrist-bones are shown in solid lines. Preferably, an overlay line
passing through the carpal bones in the each of images is utilized
as stationary bases to generate images 1030 and 1050, although
these overlay lines are not shown in images 1030 and 1050.
Lower-left Image 1040 is an AP image of Reduced Fracture, after
reduction has been analyzed by the system, to confirm image capture
for future reference and digital record-keeping.
[0195] Upper-right Image 1050 in FIG. 51 is an AP Overlay of Radial
Length to compare analysis of reduced radial bone location, with
two sets 1052 and 1054 of substantially parallel lines, also with
dashed lines for Normal and solid lines for Fractured wrist-bones.
The distance between the two sets 1053, 1054 of lines indicates
radial length measurement. Radial length lines are drawn using
radial styloid and ulnar styloid location information. The quality
of the fracture reduction is thereby analyzed; changes in radial
length may indicate an orthopaedic problem. Image 1050 enables the
user to visually inspect and analyze the quality of the fracture
reduction and, therefore, numerical values are not provided in
image 1050 in this construction. Lower-right Image 1060 is a
Lateral View of Distal Radius Fracture after Reduction to provide
Palmar Tilt analysis that compares fractured Palmar Tilt angle of 3
degrees in this example to the contralateral or `Normal` Palmar
Tilt angle of 7 degrees, although only the fractured wrist-bones
are shown in image 1060 in this construction.
[0196] FIGS. 52 and 53 are described above.
[0197] In some constructions, a guidance system is provided to
adjust the viewing area of one image on a screen to track actions
made by a user to another image on the screen, such as to focus or
zoom in on selected landmarks in each image. This feature is also
referred to as an automatic `centering` function: as a user moves a
cursor to `mark` a feature on one image, such as placing a point
for a landmark or a stationary base on an intraoperative image, the
other image on the screen is centered by the system to focus on
identical points of interest so that both images on the screen are
focused on the same anatomical site. FIG. 54 is a schematic
combined block diagram and flow chart of an identification guidance
module 1400 utilized in one construction to assist a user to select
landmarks when comparing a post- or intra-operative results image,
box 1402, with a reference image, box 1404. The module is initiated
with a Start 1401 and terminates with an End 1418. When a visual
landmark is added to a post-operative image, box 1406, the module
1400 locates all landmarks "1" on the pre-operative reference
image, box 1408, and calculates the visible area "v" within the
pre-operative image in which to scale, such as by using Equation
11:
v=[maxx(l)-minx(l),maxy(l)-miny(l)] EQ. 11
[0198] The identical landmark on the pre-operative image is located
and its center-point "c" is determined, box 1410. The identical
landmark on the pre-operative image is highlighted in one
construction to increase its visual distinctiveness, box 1414. The
pre-operative image is centered, box 1410, and scaled, box 1412,
such as by utilizing the following Equations 12 and 13,
respectively:
Center=c-(v)(0.5) EQ. 12
Scale=i/v EQ. 13
[0199] The user manipulates one or more visual landmarks in the
results image, box 1416, as desired and/or as appropriate. In some
constructions, the user manually ends the guidance activities, box
1418 and, in other constructions, the system automatically
discontinues the guidance algorithm.
[0200] In certain constructions, image recognition capabilities
provide "automatic", system-generated matching and alignment, with
a reduced need for user input. Currently utilized image recognition
provides automatic detection of selected items including: the
spherical ball marker frequently utilized in preoperative digital
templating; the acetabular cup in digital templates and in trial
prosthetics; and the Cobb Angle line, also referred to as abduction
angle.
[0201] Note that "PostOp" typically indicates post-insertion of a
trial prosthesis during the surgical procedure, and is preferably
intra-operative. The PostOp image can also be taken and analysis
conducted after a "final" prosthesis is implanted. "PreOp"
designates an image preferably taken before any surgical incision
is made at the surgical site. In some situations, the image is
taken at an earlier time, such as a prior visit to the medical
facility and, in other situations, especially in emergency rooms
and other critical care situations, the "PreOp" image is taken at
the beginning of the surgical procedure. Ball markers BM are shown
but are not utilized for alignment because ball markers can move
relative to the patient's anatomy. Further PreOp and PostOp icons
are provided to adjust viewing features such as contrast and
transparency. Preferably, at least one icon enables rotation in one
construction and, in another construction, "swaps" the images so
that the underlying image becomes the overlying image.
[0202] In certain constructions, intraoperative analysis and
guidance is also provided to a user for one or more individual
components of an implant such as an acetabular cup of a hip
implant. System 1500, FIG. 55, analyzes the orientation, including
abduction angle and anteversion, of an acetabular cup in this
construction. System 1500 includes Image Selection Module 1502,
Image Recognition Module 1504, Landmark Identification Module 1506,
Acetabular Cup Bottom Identification Module 1508 and Abduction
Angle and Anteversion Calculation Module 1510 in this construction,
with system operation and technique described below in relation to
FIGS. 56-59.
[0203] FIG. 56 is an image 1520 of an acetabular cup 1522
positioned in the left acetabulum of a patient with a circle 1524
drawn around its outer hemispherical surface to provide diameter
information for the component. In some constructions, a user
initiates component analysis by touching a finger or a stylus to
the "Diameter Information" field 1532. At any time, as described in
relation to FIG. 59 below, the user preferably is able to return to
a previous action such as by touching or clicking another field
1532, for example "Mark Greater Trochanter". In one construction,
an image recognition algorithm in Image Recognition Module 1504
automatically operates to identify the acetabular cup 1522 in the
image 1520 of FIG. 56 and surround it with the circle 1524,
bracketed by small guide dots 1526, 1528, as indicated by the
prompt "Diameter information" 1532 at the top of image 1520. In
some constructions, the guide dots or squares serve as "navigation
handles" to enable the user to manipulate one or more features
designated by the handles, such as by touching or clicking and
dragging the handles to move the designated features. This screen
1520 relates to step 1608 in flowchart X, algorithm 1600, FIG. 59
below. If the initial, auto-generated circle is not acceptable,
then the user manually adjusts the position and/or size of circle
as appropriate, step 1610.
[0204] FIG. 57 is an image 1540 similar to that of FIG. 56 with two
lines 1542 and 1560 drawn to calculate abduction angle. The user
accesses screen 1540, having a heading or prompt 1541 of "Calculate
Abduction Angle", for example, to fit in the abduction angle
landmarks for calculation. The terms "abduction" and "abduction
angle" are also known as "inclination". The "User positions neutral
axis" step 1612 in flowchart X, FIG. 59 below relates to screen
1540, FIG. 57, in which neutral axis line 1560 is placed to touch
the two ischial tuberosities of the pelvic girdle. Guide squares
1562, 1564, 1566 and 1568 enable the user to manipulate the neutral
axis line 1560. Abduction angle line segment 1542 is
auto-positioned across circle 1524 using image recognition, step
1614, FIG. 59, wherein the system automatically detects where the
acetabular cup 1522 is positioned, FIG. 57, and the system places
the line segment 1542 across the abduction angle on the cup as
accurately as it can do so. The abduction line segment 1542
preferably is a diameter line of the circle; when segment 1542 is
extended virtually by the system to intersect the neutral axis line
1560, the abduction angle is generated and measured at that
intersection. In one construction, the abduction line defaults to
about 45 degrees from the neutral line 1560 until more accurate
auto recognition occurs. The guide square "handles" 1544, 1546,
1548 and 1550 around the abduction line segment 1542 enable the
user to rotate the abduction line segment 1542, but the abduction
line continues to look like a diameter line so that it remains
properly aligned with the actual orientation of the acetabular cup
1522.
[0205] During the "User adjusts abduction angle manually if
required", step 1616, FIG. 59, the user can use the navigation
handles 1544, 1546, 1548 and 1550, FIG. 57, after the image
recognition has run, to make the abduction angle substantially
perfect. In "System calculates and displays abduction angle", step
1618, the neutral axis 1560 is mathematically compared to the
abduction line segment 1542 to determine the angle. In this
construction, the abduction angle data of "32.degree.", for
example, is displayed in lower right field 1543 in FIG. 57.
[0206] If the user wants anteversion information, then at step
1620, FIG. 59, "YES" is selected and arcs 1572, 1574, FIG. 58, are
positioned that identify the bottom of the acetabular component
1522 in step 1622. The system then calculates and displays the
anteversion angle, which relates to the z-plane rotation of the
acetabular component 1522. Some users may only want to use
abduction angle data and will then skip anteversion at step 1620
and proceed to step 1626 where it is decided whether to modify
placement of the acetabular component intraoperatively. If "yes" is
selected, then the algorithm proceeds as indicated by path 1628 to
re-position the acetabular component, step 1604 et seq. Once the
user is satisfied with the placement, then algorithm 1600
terminates, step 1630, and the system resumes from where step 1602
was initiated.
[0207] FIG. 58 is an image 1570 similar to that of FIG. 57 with
arcs drawn at the bottom of the acetabular cup 1522 to assist
calculation of anteversion in the z-plane. Image 1570 includes a
vertically-oriented "slider control" 1580 in this construction,
with vertical line 1582 and a movable setting knob 1584, to enable
a user to easily increase or decrease the size of arcs 1572 and
1574. Vertical slider control 1580 increases or decrease the size
of the arcs 1572, 1574. These arc lines 1572, 1574 are mirror
images of one another relative to the abduction line segment 1542
and are used to identify the location of the bottom of the cup 1522
in the image 1570. Sliding knob 1584 all the way to `0` will cause
the arcs 1572, 1574 to overlay the abduction angle line segment
1542. Sliding all the way to `100` will cause the arcs to overlay
the existing circle 1524. This relates to "Arcs are positioned that
identify bottom of acetabular component", step 1622, FIG. 59. Guide
handles 1569 and 1571, FIG. 58, are provided for at least one of
arcs 1572 and 1574 as described in relation to FIG. 59 below.
[0208] During the next step 1624, "System Calculates and Displays
Anteversion", any updates that are applied to the arcs 1572, 1574
via slider 1580 will lead to re-calculation and updated display of
anteversion value such as "14.degree." in field 1594. Note how the
guide handles 1573, 1575, 1577 and 1579 in FIG. 58 allow the
precise location of the abduction angle to still be updated if
required, via manipulation of abduction line segment 1542, which is
especially useful if the user continues positioning the arcs, to
more closely achieve actual orientation values. Soft-button icons
1590 and 1592 for "Abduction Angle" and "Anteversion", respectively
illustrated with solid and dashed lines, serve as "toggles" when
touched or clicked by a user to selectively activate which screen
features may be manipulated by the user. In one construction, the
functionality of one or more of guide handles 1573, 1575, 1577
and/or 1579 is altered according to which of icons 1590 and 1592 is
selected, to adjust features relating to abduction and anteversion,
respectively.
[0209] FIG. 59 is a flowchart of anteversion and abduction analysis
by the modules of FIG. 55. Flowchart X, algorithm 1600, FIG. 59, is
activated when a user selects "Cup Check" icon or text to initiate
cup analysis. In some constructions, this prompt will persist
somewhere on the navigation screen throughout the workflow. This is
a `forked` or loop workflow which will start, step 1602, from
wherever it is initiated and then return to the same place upon
finish of the fork. First action of "Position Acetabular
Component", step 1604, is conducted by a surgeon. The "acetabular
component" in this situation of "pre-stem insertion", can be a
number of components: a standard acetabular cup, a reamer, or a
trial acetabular cup. The actual component analyzed depends on what
the surgeon would like to have analyzed by the system according to
the present invention.
[0210] After initial installation of a component, a prompt such as
"Take image of acetabular component", step 1606, guides the user to
take a picture of an AP Pelvis view with implanted cup, such as
illustrated in FIG. 56. Alternatively, a prompt of "Select from
Library" or other guidance can be provided to the user, in a manner
similar to other techniques described above. Steps 1608-1616 are
described above in relation to FIGS. 56-57 in which a circle is
established around the acetabular cup and diameter information of
the circle is generated.
[0211] Initiation of step 1618, FIG. 59, "System calculates and
displays abduction angle", causes two lines to appear, the pelvic
reference line 1560 and abduction angle line segment 1542, FIG. 57,
in a manner that is similar to abduction angle analysis on
simulated AP Pelvis described above. Pelvic reference line 1560 is
also referred to as the "neutral axis" line, step 1612.
Alternatively, a "T" or other geometric shape appears on the screen
when a soft button "toggle" is activated. The pelvic reference line
1560 is a line across image 1540, placed by default horizontally on
image 1540 and approximately 75 percent of the way down the image
(in a y-coordinate system). This is similar to the Cobb Angle
functionality discussed above.
[0212] For the abduction angle line, the user draws the line
segment 1542 as precisely as possible across the cup 1522. In some
constructions, an image detection/recognition algorithm is provided
to assist this process. Abduction angle preferably is calculated in
real time and displayed in this step. In one construction, the
abduction angle continues to be displayed to the user throughout
the additional steps in this process. Determining the abduction
angle is a straightforward calculation, calculated as the angle
between the neutral axis 1560 and abduction line segment 1542, FIG.
57, similar to how it works in AP Pelvis reconstruction. When a
user such as a surgeon wants to get return to operating on the
patient and not continue with anteversion, then the user selects
"No" in steps 1620 and 1626, FIG. 59, the system "saves" the
calculated information, and returns to where algorithm 1600 was
initiated while the surgeon resumes surgery on the patient.
[0213] For step 1622, the user works with two inner arcs to analyze
anteversion. The system keeps the acetabular component circle
visible from the earlier step, but it is now non-modifiable. The
abduction line preferably is removed from the visual display.
Preferably the circle appears to be "paper thin" (and even slightly
transparent) in this screen. End points 1526 and 1528, FIG. 57, are
added on each side of the circle 1524 where the abduction line 1542
transected the visual circle 1524.
[0214] Now the system proceeds to modify the two arcs 1572 and
1574, FIG. 58, that are contained within the circle 1524. Each arc
is on one of the sides of the abduction line segment 1542. These
arcs are mirror images of one another relative to the abduction
line. Each arc should default to a distance of 35% of the circle
radius; for example, if the radius is 28 mm (or 28.times. pixels,
whatever it may be, as scaling is not needed for this process), the
distance of the midpoint of the arc from the abduction line should
be approx. 9 mm (or 9.times. pixels). One of the arcs, such as the
lower one 1574, has navigation controls or handles 1569 and 1571 on
it, or directly at the center of the arc 1574. The other arc will
move in tandem with this arc in a "captured" manner. Navigation
control for this object will be a slider control (similar to a
transparency control, but longer and vertical). As described above
for one construction, at a setting of 100 percent on the slider,
the arc will be directly on the cup, while at 0 percent on the
slider, the arc will be directly on the abduction angle line.
Preferably an initial default setting of 35 percent is provided.
Also preferably, the slider control 1580 is movable on the screen,
and is initially positioned by the system in the middle of the
screen.
[0215] Anteversion is calculated in real-time and displayed as arcs
1572 and 1574 are modified. A larger display is desired for both
abduction angle and anteversion. Anteversion is calculated in one
construction according to Liaw et al., "A New Tool for Measuring
Cup Orientation in Total Hip Arthroplasties from Plain
Radiographs", Clinical Orthopaedics and Related Research No. 451,
pp. 134-139 (2006) currently available at:
http://www.csie.ntu.edu.tw/.about.fuh/personal/ANewToolforMeasuringCupOri-
entation.pdf.
[0216] As described on Page 136 of the Liaw et al. article, FIG.
2-B shows calculation of `true anteversion` angle: Point F is
known, as the midpoint of the diameter line, and Point E can be
identified from circle surround the cup. The highest point on the
cup is point E, which has the same x-coordinate as Point F and a
y-coordinate equal to (y coordinate of Point F+radius of circle
diameter). Point G is a point on the `arc` horizontal from Point F.
Angle Beta(t), which represents true anteversion, can be calculated
from this data.
[0217] Finally, the user can Capture/Save this analysis for later
review and then `Go Back` to standard workflow. High Level Workflow
Functionality Summary: preferably, the system provides the user
with the ability to Save, Exit Cup Check, return to previous
screen, and view after the final overlay. In some constructions,
the system captures anteversion on the reconstructed AP Pelvis as
well, in addition to the abduction angle calculation that already
exists. A soft button with a designation such as "Calculate
Anteversion" is provided for the user to click or touch at the end
of `abduction angle` process in simulated AP. If selected, then
process continues, else process stops.
[0218] In some techniques, the Abduction Angle can be altered if
user decides to keep a physical handle attached to the acetabular
cup. The handle will appear on an x-ray image or fluoro image, and
can be used to determine abduction. A perpendicular line to the cup
handle line that intersects the Ischial Tub line will produce a
very accurate Abduction Angle. Finally in Flowchart X, FIG. 59, is
the user satisfied with the results? If not, the user can
reposition the acetabular cup, retake a fluoro shot, and begin the
process again as shown in the flowchart. Thus, a
software-controlled solution is achieved according to the present
invention, anatomically disconnected from the patient, to provide
intraoperative data that improves clinical decision-making during
surgery without increasing trauma to the patient.
[0219] In certain constructions, a system and method according to
the present invention includes an inventive alternative methodology
for analyzing intraoperative leg length and/or offset changes using
a different application of the stationary base, intraoperative
scaling and anatomical landmark identification techniques. Referred
to herein as `Reverse Templating", the system and method combines
the use of intraoperative data, gathered from intraoperative image
analysis, with intraoperative templating on a preoperative
ipsilateral image. The process begins in some constructions by (1)
acquiring preoperative ipsilateral and intraoperative images and
(2) scaling and aligning these images by using identifiable
features on the pelvis to serve as a stationary base, together with
intraoperative data of the acetabular component. The system
initially displays the preoperative and intraoperative images next
to one another, with the system aligning and scaling the images
relative to one another by using the identified stationary bases in
each image. The absolute scale, that is, objective scaling
according to a measurement system such as in millimeters, at least
for the intraoperative image, is determined by visually identifying
the prosthetic implant device itself while entering the known
metric size for at least one dimension of the device. Both images
are scaled in some constructions using their respective stationary
bases and, in other constructions, each image is scaled
independently, such as by using a ball marker for the preoperative
image and the known dimension of the implant for the intraoperative
image.
[0220] In preferred implementations of this Reverse Templating
method, the user is guided to identify one or more landmark points
(i.e. the tear drop anatomical feature of the pelvis) on each image
and is then guided by the system to position templates that
directly overlay the acetabular component and femoral stem implants
visible in the intraoperative image. In other words, a first,
acetabular template is superimposed over the acetabular component
and a second, femoral template is superimposed over the femoral
stem of the implant during certain preferred implementations of the
present overlay technique. This template overlay in the
intraoperative image does not calculate any offset or leg length
data directly, but it provides other intraoperative data (i.e.
abduction angle) that enables the system and user to precisely
position the acetabular component and femoral stem templates on the
preoperative image. The use of intraoperative data in the
preoperative image, as gathered from overlaying templates in the
intraoperative image, transforms this approach from an "estimation"
technique to one that provides extremely precise calculations of
intraoperative offset and leg length changes. The technique's use
of templates additionally allows the surgeon to proactively analyse
how intraoperative changes to implant selection will affect leg
length and offset.
[0221] One system that implements this intraoperative Reverse
Templating technique is shown in Intra-operative Analysis Module
1850 in FIG. 67. The method for one construction of the system is
depicted in flowchart segments 1870 and 1872, FIGS. 68A and 68B,
that comprise a Flowchart U depicting Intraoperative Templating
Flow. The system and method that implements this Intraoperative
Templating technique generates images such as shown in FIGS.
60-66.
[0222] In one construction, intra-operative Analysis Module 1850
according to the present invention, FIG. 67, includes Image
Selection Module 1852 which communicates with a Rotation and
Scaling Module 1860 that preferably includes an optional Stable
Base Identification Module 1854, shown in phantom. In this
construction, Template Input Module 1852 further communicates with
an optional Longitudinal Axis Identification Module 1856, shown in
phantom, that provides femoral axis identification in this
construction which is particularly useful if the first and second
images are not taken in virtually the same position, that is, along
the same viewing angle, and a Landmark Identification Module 1858.
All three of modules 1860, 1856 and 1858 provide inputs to
Intraoperative Template Placement Module 1862; in this
construction, Stable Base Identification Module 1854 generates a
stable base, also referred to as a stationary base formed from two
or more points selected on a patient's anatomy, as part of Rotation
and Scaling Module 1860, whose results are then provided to
Intraoperative Template Placement Module 1862. In one construction,
Module 1862 facilitates placement of digital templates of
acetabular and femoral components onto a preoperative image using
intraoperative data including templating data from the
intraoperative image. After templating, information is provided to
the Differential Analysis Module 1864 for further calculations and
analysis, including offset and leg length calculations in some
constructions. One or more of the modules 1852-1864 can interface
with a display or other interactive communication with a user.
Another optional component is an Intraoperative Templating Module
1863, shown in phantom, which provides further processing of the
output of Intraoperative Template Placement Module 1862, such as
performing "what if" planning analysis or to modify one or more of
the digital templates, before providing the results to Differential
Analysis Module 1864.
[0223] All references to "module" in relation to FIGS. 68A-69
refers to the modules of Intraoperative Analysis Module 1850, FIG.
67, with "ID" referring to "Identification". Further, the order in
which the preoperative, reference image and the intraoperative,
results image are marked or scaled among steps 1876 to 1902 can be
interchanged in other implementations. In other alternative
constructions, analysis is conducted utilizing a contra-lateral
image instead of or in addition to an ipsa-lateral image as
described below.
[0224] The method begins in one construction with initiation, step
1874, FIG. 68A, and a user-selected preoperative ipsilateral hip
image is opened for display, step 1876, by Image Selection Module
1852. The system guides the user to indicate whether the image is a
right or left hip. A screen view 1700, FIG. 60, depicts the
selected image 1702 of the right side of a patient's hip prior to
an operation, with pubic symphysis PS, obturator foramen OF and
right femur F.sub.R. The image 1702 can be acquired by directly
interfacing with an imaging system or otherwise by taking a picture
of a radiographic image using an iPhone camera or similar
technology. A label 1718 of "PreOp" indicates that it is a
pre-operative image.
[0225] The method continues with the preoperative hip image being
processed, step 1878, by the technique of flowchart 1880, FIG. 69,
which is a Flowchart Y showing functions applied to the
pre-operative hip image for Intraoperative Templating of Flowchart
U. The specific functions include identification of a `stable base`
(sometimes referred to as a `stationary base`) according to the
present invention, identification of the femoral axis, and
identification of the greater trochanter in this construction. At
step 1882, FIG. 69, a reference line is drawn by the Stable Base ID
Module 1854 across the bony pelvis, as illustrated by the "stable
base" line 1704 in FIG. 60 which is shown extending from the
teardrop TD to the lower portion of the pubic symphysis PS. A
femoral axis line 1706, representing the longitudinal axis of the
femur, is then identified in step 1884, FIG. 69, by the
Longitudinal Axis ID Module 1856. A femoral landmark such as the
greater trochanter is identified, step 1886, by Landmark ID Module
1858; in other constructions, one or more alternative femoral
landmarks such as the lesser trochanter are identified. As guided
by step 1886, guide squares 1710 and 1712, FIG. 60, assist the user
in placing a marker 1714 on the greater trochanter GT as a landmark
or reference point. In some constructions, the "stable base" line
1704, "femoral axis" line 1706, and marker 1714 on the greater
trochanter (or other femoral landmark) may be automatically placed
in appropriate locations by the system's image recognition
capabilities and then may be modified by the user. In other
constructions, the user is prompted to place these lines and
markers without system intervention.
[0226] Continuing with step 1890, FIG. 68A, the technique captures
the operative hip image, that is, an image is obtained of the
patient's hip during surgery, utilizing the Image Selection Module
1852. The operative hip image may be captured through various
methods, such as through a direct connection with a fluoroscopy
machine, a DICOM file upload, or by the user taking a camera
picture of the radiographic image using an iPad or other mobile
computing device. After capturing the operative hip image, the
acetabular component is identified in step 1892 by the Rotation and
Scaling Module 1860, such as shown in FIG. 61. The intraoperative
image is scaled, step 1894, by entering the size of the acetabular
component into the system, which is processed by Rotation and
Scaling Module 1860.
[0227] FIG. 61 represents a screen 1720 viewable by the user during
a surgical procedure guided according to the present invention
showing two images in split screen view, the left-hand image 1702'
representing a pre-operative view similar to FIG. 60, and the
right-hand image 1722 representing an intra-operative view with a
circle 1724 placed around the acetabular component 1730 of an
implant 1732 to enable rescaling of that image. In some
constructions, the system attempts to automatically place the
circle 1724 around the acetabular component 1730 using image
recognition algorithms. In other constructions, the user is
prompted to place the circle around the acetabular component
without system guidance. The user may use guide squares 1726 and
1728, if required, to alter the size and position of circle 1724 so
that it precisely encircles the acetabular component 1730. In one
construction, the user enters the diameter of circle 1724, such as
"54 mm", using data entry box 1727. This enables the system to
generate absolute scaling in the intraoperative image by taking the
diameter in pixels of the acetabular component and combining that
with the known diameter in millimeters. Other prompts to guide the
user include the choice of soft-key 1740 for "Use Ball Marker" and
soft-key 1742 for "Use Ruler", to allow the user to accomplish
intraoperative scaling using other anatomical features or
observable devices if desired.
[0228] The method continues with step 1896, FIG. 68A, by applying
Flowchart Y, FIG. 69, to the operative hip, including steps
1882-1886 as described above, in order to identify the "stable
base", "femoral axis" and greater trochanter in the operative hip
image, as illustrated in FIG. 62. The shoulder of the femoral
implant is identified, step 1898, in the intraop image by Landmark
ID Module 1858, which is also illustrated in FIG. 62.
[0229] FIG. 62 is a schematic screen view 1750 similar to FIG. 61
with pre-operative image 1702'' and indicating placement of a mark
1760 of the lateral shoulder 1761 of the prosthesis 1732 of the
right-hand, intra-operative image 1722', as guided by guide squares
1762 and 1764. Also shown is the greater trochanter having mark
1756 as a femoral landmark and a stable base line 1754 connecting
the tear drop TD to the lower portion of the pubic symphysis PS.
Alternative constructions may use a stable base line 1754 that
connects a different set of 2 or more anatomical landmarks across
the pelvis, but the landmarks must be placed on consistent points
across the preoperative and intraoperative images. Similarly,
alternative constructions may replace the greater trochanter with a
different femoral landmark (i.e. lesser trochanter) that can be
identified in both preoperative and intraoperative images. In some
constructions, the system will attempt to auto-generate placement
of the mark 1760 at the lateral should 1761 of the prosthesis, the
mark 1756 on the greater trochanter, and stable base 1754 across
pelvic landmarks, and then allow the user to modify placement.
Other constructions will prompt the user to determine placement of
this data without automated guidance.
[0230] The identification of consistent stationary bases in the
preoperative image and intraoperative images can be combined with
the absolute scaling data in the intraoperative image to apply
absolute scaling to the preoperative image. To accomplish this, the
method continues in step 1900, FIG. 68A, by scaling the
preoperative image in pixels by Rotation and Scaling Module 1860,
which scales the lines across the bony pelvis in both the
preoperative and intraoperative images so that they are of
identical size in pixels, such as by using stable base line 1704,
FIG. 61, and stable base line 1754, FIG. 62.
[0231] Continuing with step 1902, FIG. 68A, absolute scaling is
applied to the preoperative image by using the known size of the
acetabular component in the intraoperative image. Because both
images are scaled according to an identical stationary base, the
absolute scale ratio in the intraoperative image, determined by
acetabular component diameter, can be applied to the preoperative
image. This unique technique provides precise scaling to the
preoperative image by using objects of known size in the
intraoperative image and applying this scaling to the preoperative
image. The result is that a significantly more precise absolute
scaling can be determined in the preoperative image, as compared to
traditional preoperative image scaling techniques that utilize ball
markers or similar techniques.
[0232] Alternative constructions may alternatively apply absolute
scaling to the preoperative and intraoperative images directly in
each image, and without the need for a stationary base. For
example, each image may be scaled by a ball marker or other scaling
device, known magnification ratios of a radiographic device, or
direct measurements of anatomical points (such as a direct
measurement, via callipers, of the extracted femoral head, which
can be used to scale the preoperative image).
[0233] Alternative constructions may also replace the `stationary
base` with various other techniques that could be used to scale and
align the preoperative and intraoperative images relative to one
another. One example of such a construction would involve
overlaying two images and displaying them with some transparency so
that they could both be viewed on top of one another. The user
would then be prompted to rotate and change their sizing, so that
the pelvic anatomy in the two images were overlaid as closely as
possible.
[0234] A "side by side" display is generated by the Rotation and
Scaling Module 1860, step 1904, which is consistently rotated and
scaled based on the stable base line across the bony pelvis. In
some constructions, a single image that combines preoperative and
intraoperative picture renderings side by side will be displayed.
Other constructions will maintain the preoperative and
intraoperative images as separate images. All constructions will
rotate and scale the images relative to one another using the
stationary bases across the pelvis.
[0235] After aligning the preoperative and intraoperative images,
the method continues with step 1906, FIG. 68B, with the user or
system drawing an acetabular cup template directly on top of the
implant in the intraoperative image, such as shown in FIG. 63. The
acetabular cup template is placed to match the actual abduction
angle by Intraoperative Templating Module 1862. FIG. 63 is a
schematic screen view 1770 similar to FIG. 62 with a reference
rectangle 1772, also referred to as a "box" or "frame", indicating
an acetabular component template 1774, with a central point 1775,
placed directly above the acetabular component of the prosthesis on
the intra-operative femur in the right-hand view. In some
constructions, the system combines known anatomical data (i.e. the
circle 1724 placed around the acetabular component in FIG. 61) and
image recognition to generate the initial placement of the
acetabular component template on the intraoperative image. In an
alternative construction, the acetabular component template is
placed at a default abduction angle and modified by the user. In
either construction, the user can modify the template abduction
angle to match the actual acetabular component abduction angle by
using movement control icon 1776, also referred to as a "rotation
handle", similar to the icon 527 shown in FIG. 21 above. This
assists "touch" or "click and drag" control used to facilitate
repositioning and adjustment of the template 1774 relative to the
image of the acetabular component 1730 of implant 1732. In one
construction, icon 1777 is clicked or touched to "activate"
rectangle 1772, template 1774 and/or movement control icon 1776 to
enable movement thereof by the user. Additional information is
provided to the user by fields 1778 such as "Size 54 mm", "Type
Standard", and "Offset 0" as illustrated. Markers 1780 and 1782
have been placed in images 1702''' and 1722'', respectively, to
designate the location of tear drop TD in each image. In some
constructions, the system may automatically generate markers 1780
and 1782 because the teardrop TD has already been identified, for
example in a situation when the teardrop is used to create a
stationary base and can be readily identified.
[0236] In step 1908, FIG. 68B, the system positions the acetabular
cup template in identical position, relative to the pelvis, in the
preoperative image as compared to the placement on the
intraoperative image described above. This is illustrated in FIG.
64 using known teardrop locations in the pre- and intra-operative
images.
[0237] FIG. 64 is a schematic screen view 1790 similar to FIG. 63
but with the acetabular template 1774', with a central point 1775',
now re-positioned on top of the femoral head in the preoperative
view 1792. The acetabular template positioning in the preoperative
image, as shown in this figure, is auto-generated by the system
using intraoperative image data gathered from the placement of the
acetabular template in the intraoperative image. Specifically, the
system calculates the x and y distances from the teardrop to the
acetabular prosthesis in the intraoperative image display, and
auto-generates the acetabular template position in the preoperative
image by maintaining the distance from the teardrop to the
acetabular template in the preoperative image. The system also
maintains the abduction angle obtained by maintaining the
acetabular template abduction angle that was analysed in the
intraoperative image. This process ensures that the acetabular
template is placed in the preoperative image in a position,
relative to the pelvis, that precisely matches the acetabular
component position in the intraoperative image. The method
effectively transforms the templating exercise from one of
preoperative estimation and planning to one of precision-guided
intraoperative analysis. The acetabular component placement is
facilitated by the scaling and alignment of the preoperative and
intraoperative images described above.
[0238] In alternative constructions, a physical device, sensors,
caliper measurement of directly observable anatomical landmarks, or
some other form of mechanical and electrical hardware may be used
to create image scaling as a substitute for scaling based on the
acetabular component. One example of an alternative construction
(although not as precise) would be to measure the extracted femoral
head using calipers, and then to scale the image by marking the
femoral head in the preoperative image. In this method, absolute
scaling is initially created in the preoperative image, and then
propagated to the intraoperative image by scaling and aligning
consistent stationary bases.
[0239] The process continues with step 1909, FIG. 68B, by
Intraoperative Templating Module 1862, with the system or user
positioning a femoral stem template directly on top of the femoral
stem in the intraoperative image. As with the acetabular component
template process described above, this step is used to determine
intraoperative data that will be used later in the method. FIG. 65
is a schematic screen view 1800 similar to FIG. 64, demonstrating
positioning of the femoral stem template in the intraoperative
image. The figure shows the acetabular component outline 1774'
overlaid on the femoral head on the left-hand, preoperative image
1801. The user selects the femoral stem template used in surgery,
identified for this implant 1732 as "Depuy Corail AMT Size: Size 9,
Offset: COXA VARA, Head: 5", and the system renders the template
for this model on the screen. The user or system overlays the
template image 1804, within rectangle 1802, of the prosthesis 1732,
directly on top of the observed femoral component in the
intra-operative image 1803. Initial calculations of Offset Changes
and Leg Length Changes are not yet relevant, but are displayed in
one corner of screen 1800 by indicia 1812 including "Offset
Changes: -272.0 mm", and "Leg Length Changes: -12.7 mm", along with
"Abduction Angle: 45.0". Control icon 1808 for the acetabular cup
and an icon 1810 for the femoral stem template 1802 and 1804 are
provided in another portion of screen view 1800.
[0240] Note dashed 1820 extending from the neck of the implant 1732
over the greater trochanter, and a parallel dashed line 1822 which
touches the shoulder of implant 1732. (The user identified the
shoulder of the femoral prosthesis 1732, also referred to as the
superolateral border of the femoral prosthesis, in the
intraoperative image illustrated in FIG. 62 above.) The system
draws both lines 1820 and 1822 perpendicular to the femoral axis
and is guided by user positioning of markers that identify the
greater trochanter and shoulder implant.
[0241] In step 1910, FIG. 68B, the system identifies the distance
between the shoulder of the implant and the greater trochanter
along the femoral axis line, as shown in FIG. 65. In one
construction, this process is supported by dashed reference lines
1820 and 1822 which are generated to be perpendicular to femoral
axis line 1752, identified earlier in the process and displayed in
FIG. 66. The calculated distance between lines 1820 and 1822, along
the femoral stem axis, is intraoperative data that will be applied
to the placement of the femoral stem template in the preoperative
image.
[0242] In step 1912, the system takes the calculated distance
described above and generates a line in the preoperative image that
is perpendicular to the femoral axis line and is the same distance
away from the greater trochanter, as shown in FIG. 66. For step
1914, the system places the femoral stem template in the
preoperative image, using the line generated in step 1912.
[0243] FIG. 66 is a schematic screen view 1830 similar to FIG. 65
showing the femoral stem template 1804', within a rectangle 1802',
placed on the pre-operative image 1801' superimposed and aligned
with the femur F.sub.R. The system automatically repositions the
femoral stem template 1804' in preoperative image 1801' by using
intraoperative data gathered from the placement of the same
template in the intraoperative image. Specifically, the system
draws guidance lines and determines the implant position on the
femur in the preoperative image through the following steps: [0244]
1. The system draws dashed line 1832 through the greater trochanter
point (as previously identified by a marker) and perpendicular to
the femoral axis in the preoperative image (which may be different
than the intraoperative femoral axis). [0245] 2. The system takes
the calculated distance, along the femoral axis, between the
greater trochanter and the shoulder of the implant from the
intraoperative image. The system generates dashed line 1834 in the
preoperative image below the greater trochanter line 1832, and
perpendicular to the femoral axis, based on the distance calculated
in the intraoperative image. [0246] 3. Line 1834 is generated as a
visual guide for the user or system to position the femoral stem
template by placing the shoulder of the femoral stem template on
this line. [0247] 4. The system calculates the difference between
the greater trochanter and the shoulder of the prosthesis in the
intraoperative image along the femoral axis and perpendicular to
the femoral axis. The system then generates the location of the
femoral stem template in the preoperative image by replicating the
distance relative to the greater trochanter and placing the
shoulder of the prosthetic at that location. [0248] 5.
Additionally, the femoral stem is automatically rotated so that it
maintains consistent angle relative to the femoral axis in both
images. For example, if the femoral axis is 15 degrees in the
intraoperative image and 10 degrees in the preoperative image, the
system will automatically rotate the femoral stem template by 5
degrees when it moves it to the preoperative image. Finally, the
femoral stem template may be adjusted, either by the user or
automatically by the system, to match the location of the femoral
canal (i.e. movement of the femoral stem template perpendicular to
the femoral axis). [0249] 6. Having combined intraoperative data
with preoperative imaging, the system now precisely calculates, in
step 1916 and Differential Analysis Module 1864, the offset and leg
length differences based on the positioning of the femoral stem and
acetabular cup templates in the preoperative image. [0250] 7.
Finally, the user can now modify, in step 1918, implant template
selections in the system to perform "what if analysis" and to
proactively analyze how intraoperative implant changes will affect
offset and leg length calculations, allowing intraoperative changes
and decision making to be based on calculations made even before
inserting a different implant during surgery. The system or user
will then place the new implant selection using dashed line 1834
and other guidelines, and will automatically calculate anticipated
offset and leg length changes by combining the template technique
with the intraoperative data being used.
[0251] The Offset and Leg Length change calculations are displayed
in one corner of screen 1830 by indicia 1812' including "Abduction
Angle: 45.0", "Offset Changes: 4.2 mm", and "Leg Length Changes:
-0.2 mm". Also identified is "Pinnacle Acetabular Cup Size: 54 mm"
and "Depuy Corail AMT Size: Size 9, Offset: COXA VARA, Head: 5" for
implant 1732 in this example. Control icon 1808' for the acetabular
cup and an icon 1810' for the femoral stem template 1802' and 1804'
are provided in another portion of screen view 1830. In one
construction, dashed reference lines 1832 and 1834 are generated to
be perpendicular to femoral axis line 1706'.
[0252] In some constructions, the system will begin with the
JointPoint Anterior process and finish with the Reverse Templating
system. Most of the data required to do Reverse Templating can be
carried over from JointPoint Anterior by the system so that very
few steps are required by the system to process the Reverse
Templating technique.
[0253] FIG. 70 is an overlay image 2000 of a preoperative hip image
2001 and an intraoperative hip image 2003 having a trial implant
2002 in a hip with the acetabular component 2004 transacted by
stationary base lines 2006 and 2007 extending between a first point
2008 on the obturator foramen OF and a second point 2010 on the
anterior inferior iliac spine AIIS of the ileum. Also shown are two
error analysis triangles 2020 (solid lines) and 2030 (dashed
lines). Circles 2022 and 2032 in this construction represent a
landmark point on the greater trochanter in images 2001 and 2003,
respectively. Image 2000 is a representation of preoperative and
intraoperative hip images 2001 and 2003 overlaid according to
stationary base lines 2006 and 2007, respectively. Three identical
pelvic points 2024, 2026, 2028 and 2034, 2036, 2038 in images 2001
and 2003, respectively, have been identified, with the system 200,
FIGS. 4C-4F, generating triangles 2020 and 2030 for each image as
represented by FIG. 70. The triangles 2020 and 2030 can be visually
compared to analyze the error in the anatomic area containing the
stationary bases which, in this case, is the pelvis. A numerical
confidence score or other normalized numeric error analysis value
may also be calculated and displayed in the system by calculating
the distance between points, comparing them to the length of the
triangle vectors, and then normalizing the data, possibly using a
log or other such nonlinear algorithm. The visual display and/or
numerical confidence score provides efficacy analysis in the
construction. In other words, error analysis and correction is
provided in some constructions for at least one image, such as
providing a confidence score or other normalized numeric error
analysis, and/or a visual representation of at least one error
value or error factor, such as relative alignment of one or more
geometric shapes, e.g. triangles, or symbols in two or more
images.
[0254] In some constructions of the various alternative systems and
techniques according to the present invention, visual and/or
audible user instructions are sequentially generated by the system
to guide the user such as "Draw line along Pubic Symphysis".
Guidance for surgery utilizing other types of implants, and for
other surgical procedures, including partial or total knee or
shoulder replacements and foot surgery as well as wrist surgery,
will occur to those skilled in the art after reading this
disclosure. Also, other types of medical imaging using energy other
than visible light, such as ultrasound, may be utilized according
to the present invention instead of actual X-rays. Moreover, if a
computer interface tool, such as a stylus or light pen, is provided
to the user in a sterile condition, then the user can remain within
a sterile field of surgery while operating a computing device
programmed according to the present invention.
[0255] Although specific features of the present invention are
shown in some drawings and not in others, this is for convenience
only, as each feature may be combined with any or all of the other
features in accordance with the invention. While there have been
shown, described, and pointed out fundamental novel features of the
invention as applied to one or more preferred embodiments thereof,
it will be understood that various omissions, substitutions, and
changes in the form and details of the devices illustrated, and in
their operation, may be made by those skilled in the art without
departing from the spirit and scope of the invention. For example,
it is expressly intended that all combinations of those elements
and/or steps that perform substantially the same function, in
substantially the same way, to achieve the same results be within
the scope of the invention. Substitutions of elements from one
described embodiment to another are also fully intended and
contemplated.
[0256] It is also to be understood that the drawings are not
necessarily drawn to scale, but that they are merely conceptual in
nature. Other embodiments will occur to those skilled in the art
and are within the scope of the present disclosure.
* * * * *
References