U.S. patent application number 15/529036 was filed with the patent office on 2017-09-28 for computer-assisted cranioplasty.
The applicant listed for this patent is THE JOHNS HOPKINS UNIVERSITY. Invention is credited to Mehran ARMAND, Chad R. GORDON, Gerald T. GRANT, Peter LIACOURAS, Ryan MURPHY, Kevin WOLFE.
Application Number | 20170273797 15/529036 |
Document ID | / |
Family ID | 56075005 |
Filed Date | 2017-09-28 |
United States Patent
Application |
20170273797 |
Kind Code |
A1 |
GORDON; Chad R. ; et
al. |
September 28, 2017 |
COMPUTER-ASSISTED CRANIOPLASTY
Abstract
Provided is a surgical method. The method includes detecting a
location of a reference unit having a trackable element with a
detector, the detector configured to provide at least one signal
corresponding to a detected location of at least the reference
unit's trackable element, wherein the reference unit is associated
with a location of an anatomical feature of a being's anatomy;
accessing a computer-readable reconstruction of the being's
anatomy, the computer-readable reconstruction of the being's
anatomy having a first updatable orientation, wherein the first
updatable orientation is updated in response to the at least one
signal; accessing a computer-readable reconstruction of an implant
having a second updatable orientation; detecting a location of a
pointer tool comprising a trackable element with the detector, the
detector further configured to provide at least one other signal
corresponding to a detected location of at least the pointer tool,
wherein the pointer tool is associated with a location of an
anatomical feature of interest; accessing at least one
computer-readable reconstruction of a trace, the trace
corresponding to a geometry of the anatomical feature of interest
based on updated detected locations of the pointer tool;
superimposing the at least one updatable, computer-readable trace
on the second computer-readable reconstruction of the implant.
Inventors: |
GORDON; Chad R.; (Baltimore,
MD) ; ARMAND; Mehran; (Baltimore, MD) ; GRANT;
Gerald T.; (Baltimore, MD) ; LIACOURAS; Peter;
(Baltimore, MD) ; MURPHY; Ryan; (Baltimore,
MD) ; WOLFE; Kevin; (Baltimore, MD) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
THE JOHNS HOPKINS UNIVERSITY |
Baltimore |
MD |
US |
|
|
Family ID: |
56075005 |
Appl. No.: |
15/529036 |
Filed: |
November 24, 2015 |
PCT Filed: |
November 24, 2015 |
PCT NO: |
PCT/US2015/062521 |
371 Date: |
May 23, 2017 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
62117782 |
Feb 18, 2015 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 34/20 20160201;
A61F 2002/30948 20130101; A61F 2/2875 20130101; A61F 2/30942
20130101; A61F 2/3094 20130101; A61B 34/10 20160201; A61B 2090/3979
20160201; A61B 2034/108 20160201; A61B 2034/104 20160201; A61B
2034/2068 20160201; A61B 2090/395 20160201; A61B 2034/2055
20160201; A61B 2034/2057 20160201 |
International
Class: |
A61F 2/30 20060101
A61F002/30; A61B 34/10 20060101 A61B034/10; A61B 34/20 20060101
A61B034/20 |
Goverment Interests
GOVERNMENT RIGHTS
[0002] This invention was made with government support under NCATS
Grant No. UL1TR000424-06 awarded by the National Institutes of
Health. The government has certain rights in the invention.
Foreign Application Data
Date |
Code |
Application Number |
Nov 24, 2014 |
US |
PCT2014/067167 |
Nov 24, 2014 |
US |
PCT2014/067174 |
Nov 25, 2014 |
US |
PCT2014/067504 |
Nov 26, 2014 |
US |
PCT2014/067581 |
Nov 26, 2014 |
US |
PCT2014/067656 |
Nov 26, 2014 |
US |
PCT2014/067671 |
Nov 26, 2014 |
US |
PCT2014/067692 |
Claims
1. A surgical method, comprising: detecting a first location of a
reference unit comprising a first trackable element with a
detector, the detector configured to provide an at least one signal
upon detecting the first trackable element of the reference unit,
wherein the reference unit is associated with a location of a
reference anatomical feature of a being's anatomy; accessing a
computer-readable reconstruction of the being's anatomy, the
computer-readable reconstruction of the being's anatomy comprising
a first updatable orientation, wherein the first updatable
orientation is updated in response to the at least one signal;
accessing a computer-readable reconstruction of an implant
comprising a second updatable orientation; detecting a location of
a pointer tool comprising a second trackable element with the
detector, the detector further configured to provide an at least
one other signal upon detecting the second trackable element of the
pointer tool, wherein the pointer tool is associated with a
location of an anatomical feature of interest; accessing at least
one computer-readable reconstruction of a trace, the trace
corresponding to a geometry of the anatomical feature of interest
based on updated detected locations of the pointer tool; and
superimposing the at least one updatable, computer-readable trace
on the computer-readable reconstruction of the implant.
2. The surgical method of claim 1, wherein the first trackable
element and the second trackable element comprise an IR reflector
or an IR emitter.
3. The surgical method of claim 1, further comprising displaying
the computer-readable reconstruction of the trace.
4. The surgical method of claim 3, wherein displaying the
computer-readable reconstruction of the trace comprises projecting
the computer-readable reconstruction of the trace onto the
implant.
5. The surgical method of claim 4, further comprising removing
portions of the implant adjacent to an implant surface on which the
computer-readable reconstruction of the trace is projected.
6. The surgical method of claim 4, further comprising marking the
implant with a marking tool at points on the implant on which the
computer-readable reconstruction of the trace is projected.
7. The surgical method of claim 6, further comprising removing
portions of the implant adjacent to the marking on the implant.
8. The surgical method of claim 3, wherein displaying the
computer-readable reconstruction of the trace comprises projecting
the trace onto the implant, removing portions of the implant not
enclosed by a projection on the surface of the implant formed on
the implant surface on which the projected computer-readable
reconstruction of the trace is projected, and fitting the implant
onto the being.
9. The surgical method of claim 1, further comprising generating
the computer-readable reconstruction of the trace, wherein the
generating of the computer-readable reconstruction of the trace
comprises detecting an updated location of the pointer tool upon
physically contacting the anatomical feature of interest with the
pointer tool.
10. The surgical method of claim 1, further comprising attaching
the reference unit to the reference anatomical feature being's
anatomy.
11. A method of sizing an implant to an anatomical feature,
comprising: generating at least one computer-readable
reconstruction of a being's anatomy with a source, wherein the at
least one computer-readable reconstruction of the being's anatomy
includes position information corresponding to an orientation of
the source; accessing the at least one computer-readable
reconstruction of the being's anatomy and position information;
displaying an image based on the at least one computer-readable
reconstruction of the being's anatomy and the position information;
and superimposing the image onto an object.
12. The method of claim 11, wherein the at least one
computer-readable reconstruction of the being's anatomy comprises a
plurality of digital images, wherein at least one of the plurality
of digital images is associated with position information.
13. The method of claim 12, further comprising stitching the
plurality of digital images together to form the computer-readable
reconstruction of the being's anatomy.
14. The method of claim 11, wherein the object is an implant and
the displaying comprises projecting the image onto a surface of the
implant.
15. The method of claim 11, wherein the source that generates the
at least one computer-readable reconstruction of the being's
anatomy is a camera.
16. The method of claim 15, wherein the camera is an RGB
camera.
17. The method of claim 11, wherein the source that generates the
at least one computer-readable reconstruction of the being's
anatomy is a depth sensor.
18. The method of claim 11, wherein the source that generates the
at least one computer-readable reconstruction of the being's
anatomy is a combination of a depth sensor and a camera.
19. The method of claim 11, wherein the source that generates the
at least one computer-readable reconstruction of the being's
anatomy is a laser scanning device.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Patent
Application Ser. No. 62/117,782, filed on Feb. 18, 2015 the
entirety of which is incorporated herein by reference, and to
Patent Cooperation Treaty Application Ser. Nos. PCT/US14/67167
entitled "Cranial Reference Mount" filed on Nov. 24, 2014,
PCT/US14/67174 entitled "Patient-Specific Trackable Cutting Guides"
filed on Nov. 24, 2014, PCT/US14/67504 entitled "Computer-Assisted
Face-Jaw-Teeth Transplantation" filed on Nov. 25, 2014,
PCT/US14/67656 entitled "Computer-Assisted Craniomaxillofacial
Surgery" filed on Nov. 26, 2014, PCT/US14/67671 entitled
"Computer-Assisted Planning and Execution System" filed on Nov. 26,
2014, PCT/US14/67581 entitled "Orthognathic Biomechanical
Simulation" filed on Nov. 26, 2014, and PCT/US14/67692 entitled
"Real-Time Cephalometry For Cranimaxillofacial Surgery" filed on
Nov. 26, 2014, the entireties of which are incorporated herein by
reference.
FIELD
[0003] The embodiments described herein relate generally to the
field of surgery, particularly cranioplasty and craniomaxillofacial
surgery, and specifically to the field of computer-assisted
surgery.
BACKGROUND
[0004] Craniectomies requiring cranioplasty are either
decompressive following stroke/trauma--or occur as a result of
oncological ablation for masses involving the bony calvarium. In
the setting of trauma with cerebral edema, stroke with bleeding, or
autologous bone flap infections requiring removal, delayed
cranioplasties are necessary at a secondary stage. Nearly 250,000
primary brain tumors/skull-based neoplasms are diagnosed each year
resulting in a range of 4500-5000 second-stage implant
cranioplasties/year.
[0005] Craniectomy defects following resection of calvarial lesions
are most often reconstructed using on-table manufacturing, as
similar to all defects in the craniomaxillofacial skeleton. For
tumor ablative surgery--where tumors and/or processes involve the
bony calvarium--cranioplasties are most often performed primarily
using suboptimal hand-molding techniques. Currently, the standard
of care is to reconstruct the cranial defects with on-table
manipulation using a varying combination of materials. For example,
oncological defects are commonly reconstructed with "off-the-shelf"
materials, as opposed to using a pre-fabricated customized
implant--simply because the exact defect size/shape is unknown. A
variety of materials may be used to reconstruct large cranial
defects, including titanium mesh, porous hydroxyapatite (HA),
polymethylmethacrylate (PMMA), and polyether ether ketone (PEEK),
among others.
[0006] Some of these materials can be molded and/or shaped in the
operating room to approximate concave defects--especially in
instances greater than 5 cm squared in size. Of note, the most
frequently used material next to titanium mesh is liquid PMMA,
which is used alone for small defects and/or in conjunction with
titanium mesh for larger defects. It is affordable, time-tested and
easy to use. However, on-table manipulation results in some form of
craniofacial asymmetry and a post-operative appearance which is
suboptimal. Furthermore, the difficult shaping process may take
several hours--which in turn increases anesthesia, total blood
loss, risk for infection, morbidity, and all costs associated with
longer operative times.
[0007] With the advent of computer-aided design/manufacturing
(CAD/CAM) and customized craniofacial implants (CCIs), more suited
alternatives are available. Thus, CAD/CAM adds another dimension to
the material chosen for reconstruction, for example, by allowing
one to match the contralateral, non-operated side for ideal contour
and appearance. With CAD/CAM fabrication, near-perfectly shaped
CCIs can be ordered and pre-fabricated based on fine cut
preoperative computed tomography (CT) scans and three-dimensional
reconstruction (+/-stereolithographic models). In fact, recent
reports suggest that CCI's have the ability to improve cosmesis,
decrease operative times and enhance patient satisfaction.
[0008] In the literature, there are only a few case reports where
immediate reconstructions with CCI's were performed for benign
skull neoplasms following resection (i.e. meningioma, fibrous
dysplasia). While studies have reported favorable results and
acceptable outcomes, there is a trend towards decreased operative
times, and less overall surgery--by avoiding revision surgery. In
cases of malignant neoplasms involving the bony calvarium,
secondary cranioplasty (after surgical margins have been cleared)
is advocated. However, there is only one successful case report of
immediate CCI reconstruction following resection of a Ewing
sarcoma.
[0009] Historically, cranioplasties with such CCIs can only be
performed as second stage operations during which a clinician, such
as a surgeon, ensures that the CCI fits perfectly into the skull
defect. The recent developments have demonstrated the feasibility
of CCIs for "single-stage cranioplasty", but this involves using a
handheld bur to shave down the pre-fabricated implant artistically.
However, challenges in both assessing and predicting each
tumor-resection deformity pre-surgery still limits the
applicability of CCIs in this patient population. For example,
challenges such as 1) unknown exact tumor size, 2) unknown growth
from time of pre-op CT scan-to-actual day of surgery, and 3) the
unknown resection margins needed to minimize local recurrence.
Thus, in the typical case, the implant is designed preoperatively
knowing that the neoplasm may be larger (i.e. may have grown in the
interim, more invasive to the surrounding tissues, etc.) than the
pre-op radiographic imaging depicts, which means removing more
normal tissue along the periphery to help minimize local tumor
recurrence. In some cases, surgeons may resect the diseased bone
using a cutting template (i.e. pre-fabricated guide) to help
eradicate the need for intra-operative modification and additional
labor, but this technique does not follow true oncological
principle--since the tumor resection should be limitless and
ideally based on visual evaluation, rather than the pre-operative
radiographic study. For these cases, the CCI would need to be
reshaped/resized intraoperatively from a size slightly larger than
expected--which is a process that may take, on average, between
10-80 minutes.
[0010] Accordingly, use of a computer-assisted surgical system of
an embodiment may significantly reduce the intraoperative time used
for reshaping/resizing the customized implant. However, with no
established planning and execution systems available to assist
these single-stage reconstructions, a technology and/or surgical
method that allows surgeons to resize, adjust, modify or trim
alloplastic or bio-engineered implants during surgery to fit the
surgical cuts, defects, and/or pre-existing deformities requiring
complex reconstruction, or generally overcome the limitations of
current technology and surgical methods, would be welcome in the
art.
SUMMARY
[0011] In an embodiment, there is a surgical method. The method
includes detecting a location of a reference unit having a
trackable element with a detector, the detector configured to
provide at least one signal corresponding to a detected location of
at least the reference unit's trackable element, wherein the
reference unit is associated with a location of an anatomical
feature of a being's anatomy; accessing a computer-readable
reconstruction of the being's anatomy, the computer-readable
reconstruction of the being's anatomy having a first updatable
orientation, wherein the first updatable orientation is updated in
response to the at least one signal; accessing a computer-readable
reconstruction of an implant having a second updatable orientation;
detecting a location of a pointer tool comprising a trackable
element with the detector, the detector further configured to
provide at least one other signal corresponding to a detected
location of at least the pointer tool, wherein the pointer tool is
associated with a location of an anatomical feature of interest;
accessing at least one computer-readable reconstruction of a trace,
the trace corresponding to a geometry of the anatomical feature of
interest based on updated detected locations of the pointer tool;
superimposing the at least one updatable, computer-readable trace
on the second computer-readable reconstruction of the implant.
[0012] In another embodiment, there is a method of sizing an
implant to an anatomical feature. The method includes generating at
least one computer-readable reconstruction of a being's anatomy
with a first source, wherein the at least one computer-readable
reconstruction of the being's anatomy includes position information
corresponding to an orientation of the first source; accessing the
at least one computer-readable reconstruction of the being's
anatomy and position information; displaying an image based on the
at least one computer-readable reconstruction of the being's
anatomy and the position information; and superimposing the
displayed image onto an object.
[0013] Additional advantages of the embodiments will be set forth
in part in the description which follows, and in part will be
understood from the description, or may be learned by practice of
the embodiment(s). The advantages will be realized and attained by
means of the elements and combinations particularly pointed out in
the appended claims.
[0014] It is to be understood that both the foregoing general
description and the following detailed description are exemplary
and explanatory only and are not restrictive of the embodiment(s),
as claimed.
[0015] The accompanying drawings, which are incorporated in and
constitute a part of this specification, illustrate embodiments
described herein and together with the description, serve to
explain the principles of the embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIGS. 1A-1C provide schematic overviews of a
computer-assisted surgical system.
[0017] FIGS. 1D-1H are graphical reconstructions of some components
and/or features of the surgical system of FIGS. 1A-1C.
[0018] FIG. 2 is a flowchart depicting representative steps for
executing a method of an embodiment.
[0019] FIG. 3 is a flowchart depicting representative steps for
executing a method of an embodiment.
[0020] FIG. 4 is a flowchart depicting representative steps for
executing a method of an embodiment.
[0021] FIG. 5 is a flowchart depicting representative steps for
executing a method of an embodiment.
[0022] FIG. 6A illustrates an example tracker digitization. A
reference geometry is attached to the patient (via a cranial mount,
for example) and to a digitizer. A tracking unit, such as an
optical tracker, tracks the reference geometries. The digitizer
captures the outline of the cut region.
[0023] FIG. 6B illustrates a three dimensional rendering formed
according to a computer-readable reconstruction of a being's
anatomy including a representation of a cranial defect as captured
using the system of FIG. 6A.
[0024] FIG. 6C illustrates the three dimensional rendering of FIG.
6B and includes an implant overlay for use in performing a
computer-assisted cranioplasty in accordance to an embodiment. The
implant overall is a computer-readable representation of a geometry
defining the dimensions of a resized implant and may be
superimposed over the three dimensional rendering.
[0025] FIG. 6D is a distance map generated from a quantitative
analysis between dimensions of the implant and dimensions of a
defect site on a being's anatomy.
[0026] FIG. 7 illustrates an example for camera digitization. The
camera can be any of a standard color (RGB) camera, a depth sensor,
or a combination of RGB and depth (like the Structure sensor,
http://structure.io/). The camera is attached to a passive arm of a
stand. The surgeon uses the camera to take several pictures of a
cut region (i.e., a geometry of a patient's anatomical defect).
Each time a picture is taken, the camera position is recorded. This
information may be stitched into a 3D model from which an outline
of the cut region may be extracted.
[0027] FIG. 8A illustrates an example setup that may be a part of a
surgical system for projecting a trace onto the implant according
to an embodiment. The setup includes a stand on which the implant
is placed and a projector, which may be connected to the stand, for
projecting a trace/image onto the implant.
[0028] FIG. 8B illustrates an alternative example setup that may be
a part of a surgical system for projecting a trace onto an implant
according to an embodiment The setup includes a stand on which the
implant is placed and a projector, which may be connected to the
stand, for projecting a trace/image onto the implant.
[0029] FIGS. 9A-9D illustrates an example surgical method according
to an embodiment. In FIG. 9A, an anatomical feature of interest
(e.g., a defect) is identified. In FIG. 9B, an oversized implant
(with four tabs for mounting and image alignment) is shown with a
trace/image of a patient's anatomical defect generated according to
an embodiment (i.e., a resected overlay) is superimposed/projected
on the surface of the implant. In FIG. 9B, a surgeon traces the
projected resected overlay with a sterile marking pen directly onto
a surface of the implant and then shaves off excess implant
material. In FIG. 9D, the resized implant is shown attached to the
resected surface of the being's anatomy.
[0030] FIG. 10 is a flow chart depicting an embodiment of a
surgical method which can be executed for sizing an implant to an
anatomical feature.
[0031] FIG. 11 is a flow chart depicting an embodiment of a
surgical method which can be executed for sizing an implant to an
anatomical feature.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0032] Reference will now be made in detail to the present
embodiments, examples of which are illustrated in the accompanying
drawings. Wherever possible, the same reference numbers will be
used throughout the drawings to refer to the same or like
parts.
[0033] Notwithstanding that the numerical ranges and parameters
setting forth the broad scope of the embodiments are
approximations, the numerical values set forth in the specific
examples are reported as precisely as possible. Any numerical
value, however, inherently contains certain errors necessarily
resulting from the standard deviation found in their respective
testing measurements. Moreover, all ranges disclosed herein are to
be understood to encompass any and all sub-ranges subsumed therein.
For example, a range of "less than 10" can include any and all
sub-ranges between (and including) the minimum value of zero and
the maximum value of 10, that is, any and all sub-ranges having a
minimum value of equal to or greater than zero and a maximum value
of equal to or less than 10, e.g., 1 to 5. In certain cases, the
numerical values as stated for the parameter can take on negative
values. In this case, the example value of range stated as "less
that 10" can assume negative values, e.g. -1, -2, -3, -10, -20,
-30, etc.
[0034] The following embodiments are described for illustrative
purposes only with reference to the figures. Those of skill in the
art will appreciate that the following description is exemplary in
nature, and that various modifications to the parameters set forth
herein could be made without departing from the scope of the
present embodiments. It is intended that the specification and
examples be considered as examples only. The various embodiments
are not necessarily mutually exclusive, as some embodiments can be
combined with one or more other embodiments to form new
embodiments.
[0035] In cranioplasty, surgeons remove bone to correct conditions
such as a tumor. Preoperative imaging such as CT or magnetic
resonance imaging (MRI) identifies the patient anatomy. The surgery
is planned using this imaging to identify an area of interest
(e.g., the tumor). Bony cuts are created virtually and the implant
is designed to fit into the resected region. In single-stage
cranioplasty, this implant is ordered oversized to account for
additional bone that may be removed during the operation. After
resecting the bony region of interest the surgeon shaves down the
oversized implant to fit into the resected area. In embodiments
described herein, there are methods and devices for reducing the
time necessary for reducing the size of an implant for better
sizing relative to the removed bone. The methods rely on the use of
a computer-assisted surgery system (here, a CAPE system).
[0036] A CCI may be either supplied by a third-party vendor,
printed with an additive or subtractive manufacturing device, such
as a 3D printer, that receives instructions generated provided by a
system of the embodiments, as described below, so that a custom
implant is available to the surgeon and placed utilizing feedback
from the CAPE system to achieve ideal positioning and alignment to
the native anatomy. An embodiment of the CAPE system described
above can be used to provide the clinician with real-time visual
feedback as to the ideal positioning of the implant (i.e. planned
versus actual). Also, the CAPE system can access computer-readable
reconstructions of a being's anatomy, such as computer-readable
files containing soft tissue and/or skeletal CT scan data, which
may be uploaded ahead of time into a memory of a computer of the
CAPE system, and which can be utilized to by a clinician for
predicting a patient's appearance during and after surgery.
[0037] At least some embodiments described herein can be used for
the immediate surgical repair of large cranial defects (e.g., >5
cm.sup.2). For example, embodiments described herein may be used
for designing, forming and implanting customized craniofacial
implants following benign/malignant skull neoplasm (tumor)
resection (i.e., referred to as "single-stage implant
cranioplasty").
[0038] For example, embodiments provide visualization related to a
tumor, the resulting skull defect, and the reshaped implant for
exact positioning. In other words, in an embodiment, a CAPE system
can be used for improving both the pre-operative planning and
intra-operative execution of single-stage implant
cranioplasties.
[0039] As described above, cranioplasties may be performed to
reconstruct large defects following stroke, trauma, aneurysmal
bleeding, bone flap removal for infection, and oncological
ablation. With this in mind, embodiments described herein include a
computer-assisted algorithm that may allow surgeons to reconstruct
tumor defects with pre-customized CCIs for an ideal result.
[0040] Accordingly, embodiments described herein may be used by
surgeons in performing single-stage cranioplasty following
oncological resection. In other words, embodiments include
algorithms for real-time updates related to single-stage customized
implant cranioplasty. For example, in an embodiment, a CAPE system,
which is a single, seamless platform capable of being used for both
planning (pre-op use) and navigation (intra-op use), overcomes the
limitations of conventional systems that do either one or the
other. In addition, embodiments include novel hardware such as a
rigid cranial reference mount.
[0041] A computer-assisted surgical system, such as the system 100
is depicted in FIGS. 1A-1G. System 100 may be utilized, for the
pre-operative planning and intra-operative execution of a
single-stage implant cranioplasty 100-R instead of (or in addition
to) transplantation. For example, in a single-stage implant
cranioplasty, a being's anatomy 108, which may be that of a human
being, may include an anatomical feature 111-D, such as a diseased
portion of the anatomy, that requires removal or replacement with
an implant 111-i. During a surgical procedure, the anatomical
feature 111-D may be separated from the being 108 by cutting away
from healthy portions 109-R of the being's anatomy. For example, a
custom-made cutting guide 106-D may be used to provide a surgeon
with slots that provide access for a cutting tool at preselecting
cutting locations along the being's anatomy. After cutting
sufficiently through the being's anatomy at the locations specified
by the cutting guide 117-D, the anatomical feature is removed away
from the being. Subsequently, an implant, such as a customized
craniofacial implant 111-I, which may be fabricated via additive or
subtractive manufacturing technology, may be attached near the
healthy portions 109-R of the being's anatomy via an attachment
119-R.
[0042] System 100 may include a reference unit 105-R, an implant
111-I and a detector 113-R. The reference unit 105-R may include a
first trackable element 101-R. The implant may include a second
trackable element 101-I. The implant 111-I may include an
attachment 119-R which may have a contoured attachment surface
107-R. In addition to, or instead of trackable element 101-R, the
attachment 119-R may also include one of a second trackable element
117-R. The detector may be configured to provide at least one
signal 191 corresponding to a detected location of at least one of
the first trackable element 101-R and the second trackable element
117-R. Reference unit 105-R may include a cranial reference mount
103-R that may be attached to a first anatomical feature 110 (such
as a reference feature of a being's anatomy) to provide a static
frame of reference for tracking the location of first trackable
element 101-R.
[0043] The system 100 may further include a cutting guide 106-D
having a third trackable element 117-D, and may be detected by the
detector 113-R. Thus, the at least one signal 191 may further
correspond to a detected location of at the third trackable element
117-D of the cutting guide 106-D. The cutting guide 106-D may be a
surgical guide assembly having an attachment device 108-D
configured to be coupled to a bone. A cut location indicator 110-D
may be coupled to the attachment device. The cut location indicator
identifies a location where the bone is to be cut. The support
structure may be configured to have the third trackable element
117-D coupled thereto.
[0044] The system 100 may also include at least one computer 115-R,
that receives the at least one signal 191 from detector 113-R, may
also include an additive manufacturing device 187, which may be in
communication with and controlled by the computer 115-R. The
computer may be connected to a display on which computer-readable
reconstructions of items, such as the implant and a being's
anatomy, may be displayed. The at least one signal 191 may be
communicated between the detector and computer via a communications
link, which may include data transmission wires and/or wireless
transmissions either of which may be communicated through a
network, such as a local area network (LAN) or wide area network
(WAN), including communication over an intranet or over the
internet, including TCP/IP data transfer. The at least one computer
115-R may be selected from a desktop computer, a network computer,
a mainframe, a server, or a laptop. The at least one computer may
be configured to access at least one computer-readable
reconstruction of at least one object, such as a being's anatomy,
or at least portions of the being's anatomy, for example, a first
computer-readable reconstruction 181 and a second computer-readable
reconstruction 185, and a third computer-readable reconstruction.
The computer-readable reconstruction may include three-dimensional
(3D) views, such as those created by scanning a patient via, for
example, CT scan. At least one display may be connected to the at
least one computer 115-R. The display may be configured to
represent the computer-readable reconstruction in a format visible
to a user. The first computer may include at least one memory to
store data and instructions, and at least one processor configured
to access the at least one memory and to execute instructions such
as instructions included in software files.
[0045] The detector 113-R may be an optical tracker, a magnetic
tracker or both an optical tracker and a magnetic tracker. Optical
trackers typically emit and capture light in the invisible
(infrared) electromagnetic spectrum. Trackable fiducials (i.e., the
trackable elements) used with these systems can include passive
(i.e., reflective) or active (i.e., those that actively emit
infrared light) markers. Using specific geometries known to the
camera, the pose of a reference can be tracked through a field of
view (as indicated by the dash-dotted lines). An example system is
the NDI Polaris available from Northern Digital, Inc. (Ontario,
Canada). Magnetic trackers rely on a magnetic field generator and
(typically) a passive coil architecture. The field generator
creates a time-varying field, which induces a current in the
passive sensor. This current is measured and, through a calibration
procedure, used to identify up to a 6-dof pose of the sensor. An
example system is the NDI Aurora available from Northern Digital,
Inc. (Ontario, Canada).
[0046] One or more of the first trackable element 101-R, the second
trackable element 101-I, and the third trackable element 117-D, may
be an infrared (IR) reflector or an IR emitter, each of which may
be detachably connected to an attachment surface. As an example, an
IR reflector may be a detachably connected surface, such as a
sphere. As an example, an IR emitter may be a light emitting diode
configured to emit infrared light.
[0047] The implant 111-I may be fabricated during a surgical
procedure by an additive or subtractive manufacturing device, or
may be a pre-fabricated implant such as a 3.sup.rd-party sourced
alloplastic implant, including a customized craniofacial implant
(CCI) implant. In an embodiment, the implant may include a polymer,
metal, bioengineered material, or combinations thereof. For
example, the implant may include titanium mesh, porous
hydroxyapatite (HA), polymethylmethacrylate (PMMA), polyether ether
ketone (PEEK) and/or combinations thereof.
[0048] The first computer may include at least one memory to store
data and instructions, and at least one processor configured to
access the at least one memory and to execute instructions, such as
instructions 200 included in the flow chart in FIG. 2. Instructions
200 may include one or more of the steps included in the flowchart
on FIG. 2. For purposes of providing examples, some of the steps
are described below with reference to components of system 100 from
FIGS. 1A-1G.
[0049] In an embodiment, instructions 200 include accessing a first
computer-readable reconstruction of a being's anatomy at 201 and
accessing a second computer-readable reconstruction of an implant
at 202. The first computer-readable reconstruction of the being's
anatomy may include a first updatable orientation and the second
computer-readable reconstruction of the implant may include a
second updatable orientation.
[0050] During a surgical procedure, such as an implantation of an
alloplastic, metal and/or bioengineered implant onto the
craniomaxillofacial anatomy of a patient being's anatomy (i.e. head
or face), it is useful to track the location of the implant
relative to the anatomy of the patient being before, during and/or
after the implantation. Accordingly, a signal--such as the at least
one signal 191 in the system 100--may correspond to a location of
the first, second and/or third trackable element as detected by the
detector 113. Thus, the instructions 200 may also include updating
the orientation of the first, second and/or third computer-readable
reconstruction of the implant with an orientation that is updated
based on the signal, which may correspond to a physical location of
the first, second and/or third trackable element, respectively, as
sensed by the detector. For example, at 203, the instructions 200
may also include updating at least one of the first (updatable)
orientation and the second (updatable) orientation. In an example,
step 203 may be initiated by user input, for example, via user
interaction with the computer, or by a signal, such as a signal
provided by a detector. As described above, the first orientation
and the second orientation may be updated, for example, on a
display connected to the computer, in response to the at least one
signal.
[0051] The instructions 200 may include superimposing a planned
cutting plane over portions of the first computer-readable
reconstruction at 204. Other steps may include generating a second
computer-readable reconstruction of an implant at 205 and
controlling an additive manufacturing device at 206 to form an
implant. In an example, the second computer-readable reconstruction
of the implant generated at 205 may include a geometry defined by
at least one of: i) an interface between the planned cutting plane
and the first computer-readable reconstruction, and ii) a selected
portion of the computer-readable reconstruction, the selected
portion comprising an anatomical feature of the being's anatomy,
including but not limited to oncological defect sites, such as a
benign/malignant skull neoplasm, large defects following stroke,
trauma, aneurysmal bleeding, bone flap removal for infection, and
oncological ablation. Additionally, the implant fabricated by the
manufacturing device at 206 may have dimensions defined by the
geometry of the second computer-readable reconstruction.
[0052] The instructions 200 may also include generating a third
computer-readable reconstruction of a cutting guide at 207 and
controlling the additive manufacturing device to form a cutting
guide at 208. In an example, the third computer-readable
reconstruction of the cutting guide may include a geometry defined
by an interface between the planned cutting plane and the first
computer-readable reconstruction, and may also include a third
updatable orientation. Additionally, the cutting guide fabricated
by the manufacturing device at 208 may include selected dimensions
of the geometry of the third computer-readable reconstruction.
[0053] The device may be any manufacturing device that fabricates
an object based on instructions, such as computer-readable
instructions, for example, instructions provided in digital data,
including any device that utilizes additive or subtractive
manufacturing technologies, such as those that fabricate an object
from appropriately approved materials for medical use.
[0054] Accordingly, the at least one device may be an additive
manufacturing device, such as a 3D printer, or another kind of
manufacturing device, including subtractive manufacturing device,
such as a Computer Numerical Control (CNC) machine. Examples of
additive manufacturing technologies may include vat polymerization
(e.g., PROJET.RTM. 6000, 7000, 8000 available from 3D Systems
Corp., Rock Hill, S.C.), materials jetting (e.g., Objet500 or
Eden250, each available from Stratasys, Ltd., Eden Prairie, Minn.),
powder binding (e.g., PROJET.RTM. 460, 650 available from 3D
Systems Corp., Rock Hill, S.C.), powder fusion (e.g., EBM.RTM.
available from Arcam AB, Sweden), material extrusion (e.g.,
Fortus250 or Fortus400, available from Stratasys, Ltd., Eden
Prairie, Minn.), or any one denoted by the ASTM F42 committee on
additive manufacturing. Accordingly, system 100 may include a
device (not shown) for manufacturing components, such as cutting
guides, reference units and/or the trackable elements, and the
device may be connected to the at least one first computer via the
communications link described above. The instructions may also
include generating a computer-readable file that contains
instructions for manufacturing the cutting guide and/or implant,
for example a computer-readable file that contains dimensions of a
component, such as a cutting guide based on the geometry of the
third computer-readable reconstruction. The computer-readable
reconstruction of the being's anatomy may be a computer-readable
file created from a CT-scan. For example, the computer-readable
reconstruction may be a 3D reconstruction of a patient's
anatomy.
[0055] In an embodiment, there is also a computer-assisted surgical
method. The method includes use of the CAPE system, which may
provide a user enhanced implant reconstruction experience, for
example, providing a surgeon unprecedented, immediate visual
feedback and allowing single-stage implant cranioplasty and all
related craniomaxillofacial reconstruction for scenarios related to
skull neoplasms, etc--in situations where the tumor defect is not
known beforehand, but where a customized implant is needed
requiring on-table modification via CAPE system guidance.
[0056] Generally, the method can include the following: a)
generating and/or accessing a computer-readable reconstruction of a
patient's anatomy, such as via a preoperative CT scan that includes
an anatomical feature, such as a defect, and constructing a 3D
model of the anatomy; b) preselecting a resection area on the
model; c) determining implant dimensions (can be a few millimeters
greater than the size of the defect) and fabricating the implant
with an additive and/or subtractive manufacturing device
incorporated with the CAPE system; d) designing a trackable cutting
guide based on the 3D model and fabricate with an additive and/or
subtractive manufacturing device incorporated with the CAPE system;
e) attaching a reference unit having a trackable element onto the
patient's anatomy, such as at the patient's skull; f) registering
the location of the trackable element/reference unit to the
computer-readable reconstruction (preoperative CT scan); g) using
the optically trackable cutting guide to perform bone cuts in the
patient; h) using a detector to generate a signal in response to
performing a trace of the defect boundaries, for example, if
additional resection is required; i) superimposing information
corresponding to signals generated by optical digitizer, such as
signals in response to performing a trace of the defect boundaries,
on the computer-readable reconstruction; j) registering the implant
to the computer-readable reconstruction with the optical digitizer,
for example, via tracking a location of a trackable element
attached to the implant; k) tracing cut lines on the implant based
on information obtained from the 3D model, such as a size mismatch
between the implant and the defect; l) attaching the implant to the
patient; m) obtaining a post-operative image of the patient and the
attached implant, such as a CT scan.
[0057] The method may include any step or combination of steps
included in the flow charts of FIG. 3-4 and described below. In an
example shown in the flow-chart of FIG. 3, with reference to the
features of the system 100 in FIGS. 1A-1H, a method 300 can include
attaching a reference unit that includes a first trackable element
to a first anatomical feature of a being's anatomy at 301. The
method may also include detecting a location of at least the first
trackable element with a detector at 302, and accessing a first
computer-readable reconstruction of the being's anatomy at 303. The
detector may be detector 113 as described above, and may be
configured to provide at least one signal corresponding to a
detected location of at least the first trackable element. The
first computer-readable reconstruction may be first
computer-readable reconstruction 181 and may include a first
updatable orientation. Accordingly, the first updatable orientation
may be updated in response to user input and/or the at least one
signal such as the at least one signal 191 described above.
[0058] In an embodiment, a method 400 may include one or more or
all of the steps of method 300 of FIG. 3 and may also include any
step or combination of steps included in the flow charts of FIGS.
3-5. In an example shown in the flow chart of FIG. 4, in addition
to method 300, method 400 may include generating a second
computer-readable reconstruction of an implant at 401. The second
computer-readable reconstruction may be second computer-readable
reconstruction 185 as described above, and may include a second
updatable orientation, such as an orientation that may be updated
in response to user input and/or the at least one signal, such as
the at least one signal 191 described above. The method 400 may
also include assessing a size-mismatch between at least one
dimension of a portion of the first computer-readable
reconstruction, for example, a portion corresponding to a selected
anatomical feature of the being's anatomy, and at least one
dimension of the second computer-readable reconstruction at 402. In
an example, assessment of the size-mismatch may be performed via a
cephalometric analysis, including a real-time cephalometric
analysis. The method 400 may also include tracing cut lines on the
implant based on the size-mismatch. In an example, the cut lines
may be traced on the implant such that an anatomical discrepancy at
an area of removal or reconstruction of the anatomical feature is
minimized. In an example, the anatomical discrepancy may be
minimized based on a preselected tolerance, for example, in
instructions provided for fabricating the implant, including
instructions provided in computer-readable files, such as digital
data, provided to an implant manufacturing device. The method 400
may also include attaching the implant to a preselected anatomical
feature at 404, such as to a patients anatomy surrounding
oncological defect sites, such as a benign/malignant skeletal
neoplasm, or large defect sites formed following stroke, trauma,
aneurysmal bleeding, bone flap removal for infection, and
oncological ablation. After implantation of the implant at 404, for
example, the method can also include obtaining a post operative
image of at least the implant attached to the preselected
anatomical feature at 405. For example, a CT scan may be taken of
the patient with implant attached.
[0059] In an embodiment, a method 500 may include one or more or
all of the steps of method 300 in FIG. 3, and may also include any
step or combination of steps included in the flow charts of FIGS.
3-5. In an example shown in the flowchart in FIG. 5, in addition to
method 300, method 500 may include superimposing a planned cutting
plane over portions of the first computer-readable reconstruction
at 501. In an example, the planned cutting plane may be
superimposed to bisect the first computer-readable reconstruction
to define at least one portion of the first-computer-readable
reconstruction corresponding to at least one diseased anatomical
feature of the being's anatomy that is to be removed or replaced.
Accordingly, the planned cutting plane may be planned cutting plane
as described above, and the first computer-readable reconstruction
may be the first computer-readable reconstruction 181 as described
above. The method 500 may also include accessing a second
computer-readable reconstruction of an implant at 502 and
fabricating an implant at 503. The second computer-readable
reconstruction may be second computer-readable reconstruction 185
as described above, and may include a second updatable orientation,
such as an orientation that may be updated in response to user
input and/or the at least one signal, such as the at least one
signal 191 described above. The implant may be implant 111-I
described above, and may include dimensions that correspond to the
geometry of the second computer-readable reconstruction.
Additionally, a second trackable element may be provided on the
implant. For example, a second trackable element such as trackable
element 101-I as described above, may be may be incorporated in the
design of the implant as a detachably connected trackable element,
or may be formed separate from the implant and attached to the
implant. It is noted that the at least one signal, such as the at
least one signal 191, may also correspond to a detected location of
the second trackable element, such as that detected by detector
113. It is also noted that the planned cutting plane may also
include a fourth updatable orientation, such as an orientation that
may be updated in response to user input.
[0060] The described method may be utilized during a surgical
procedure, such as a surgical implantation procedure for various
forms of craniomaxillofacial surgery including an implant-based
cranioplasty. The implant may be a custom, 3D craniofacial implant
made of either alloplastic materials or biologic tissue engineered
cells as described above for implant 111-I and a being, such as a
recipient being, on whom the surgical procedure is performed.
[0061] During a surgical procedure, such as an implantation of an
alloplastic, metal and/or bioengineered implant onto the anatomy of
a patient, it is useful to track the location of the implant
relative to the anatomy of the patient before, during and/or after
the implantation. Accordingly, the signal--such as the at least one
signal 191 in the system 100--may correspond to a location of the
first, second and/or third trackable element as detected by the
detector 113. Thus, the computer-assisted surgical method of the
embodiments may include updating the orientation of the first,
second and/or third computer-readable reconstruction of the implant
with an orientation that is updated based on the signal, which may
correspond to a physical location of the first, second and/or third
trackable element, respectively, as sensed by the detector.
[0062] In an example, the CAPE surgical system of the embodiments
as described herein can be utilized by a user, such as a surgeon,
to quickly and accurately shave down an oversized CCI. Such an
oversized CCI may be designed to the curvature specific only to the
patient's skull--using information about the intraoperative bony
resection following instantaneous, computer-assisted registration.
In an embodiment of a surgical method described with reference to
FIGS. 6-9, a clinician (for example, a surgeon) digitizes points of
the removed anatomical feature, such as a cut region from which
bone is removed to correct conditions such as a tumor, and the
anatomical defect is assessed in real-time using the CAPE system.
In other words, a computer of the system accesses first
computer-readable reconstruction of a being's anatomy, which may be
preoperative surface models of the skull (e.g., segmented from CT).
Additionally, a computer of the system may access a second
computer-readable reconstruction of an implant, which may be a
surface model of the oversized pre-fabricated CCI.
[0063] As illustrated in FIGS. 6A-6D, digitization can be achieved
through tracking technology such as an optical (infrared) and/or
electromagnetic trackers (detector 113) as in system 100. A
trackable pointer tool 101-D with a digitizer (a trackable element)
and/or a reference unit 105-R can be tracked by the detector 113.
As described previously, the tracker may be a detector that
generates signals in response to sensing a trackable element of the
trackable pointer tool 101-D and/or of reference unit 105-R. The
trackable pointer tool 101-D can be used for tracing a geometry of
the region of interest 112, the geometry being digitized and
converted into a computer-readable pattern such as a trace. For
example, as shown in FIG. 6B, by using a registration between the
patient anatomy and patient model (i.e., a computer-readable
reconstruction of the patient's anatomy) such as via a location of
a static point provided by reference element 105-R, the points from
the digitized trace 112 can be transformed to a patient model such
as the computer-readable representation of the being's anatomy 108.
In other words, as the clinician traces the geometry of the region
of interest 112, the detector 113 detects an orientation and
location of the trackable pointer tool 101-D relative to a location
of the reference unit 105-R, generates signals corresponding to the
sensed location of the trackable pointer tool 101-D and/or
reference unit 105-R and sends those signals to a computer which,
in turn, generates a computer-readable reconstruction of the
geometry which can be superimposed over a computer-readable
reconstruction of the patient's anatomy. As shown in FIG. 6C, a
computer-readable representation 601 of the geometry of a
pre-fabricated implant may be superimposed over the
computer-readable representation of the being's anatomy 108 to show
offset in sizing. In some instances, the pre-fabricated implant's
dimensions, for example, thickness, may not match the skull
thickness. Accordingly, a distance map 603 shown in FIG. 6D may be
generated to show similarities/differences between the implants and
defects by identifying the closest point on the implant for each
vertex of a corresponding defect surface.
[0064] Accordingly, a surgical method can include attaching a
reference unit 105-R having a first trackable element to a first
anatomical feature 110 of a being's anatomy 108; detecting a
location of at least the first trackable element with a detector
113 configured to generate at least one first signal corresponding
to a detected location of at least the first trackable element, the
generated signal being provided to, for example, a computer 115-R
having a memory and a processor for executing instructions. The
method may include accessing a first computer-readable
reconstruction of the being's anatomy, the first computer-readable
reconstruction comprising a first updatable orientation, wherein
the first updatable orientation is updated in response to the at
least one first signal. The method can also include accessing a
second computer-readable reconstruction of an implant, the second
computer-readable reconstruction comprising a second updatable
orientation. The method may also include detecting a location of at
least one second trackable element of, for example, the trackable
pointer tool 101-D with the detector 113. The detector may further
be configured to generate at least one second signal corresponding
to a detected location of at least the second trackable element of
the trackable pointer tool 101-D, the second generated signal being
provided to, for example, computer 115-R. Thus, the method may also
include generating at least one updatable, computer-readable trace,
the trace corresponding to a geometry based on updated location
data for the at least one second trackable element of the trackable
pointer tool 101-D. The method also includes superimposing the
least one updatable, computer-readable trace over portions of the
second computer-readable reconstruction of the implant. In an
example, a location of the superimposed computer-readable trace may
be manipulated based on user input.
[0065] In another embodiment illustrated in FIG. 7, a
computer-readable reconstruction of the region of interest 112,
which may be a removed anatomical feature, and/or of other portions
of a being's anatomy may be captured via the use of a source 114
for generating the computer-readable reconstruction. The
computer-readable reconstruction may be at least one digital image
which may be provided to or accessed by computer 115-R. The source
114 may be attached to a passive stand and arm arrangement 116, for
example an arrangement that includes encoders, so that it is
configured to relay positional information, such as a relative
position to a known reference point and tie the positional
information with the at least one digital image based on an
orientation of the source when such digital image(s) is capture.
While in one embodiment, a camera may be attached to the passive
arm such as in FIG. 7, any source for generating a
computer-readable reconstruction of subject being imaged may be
used. Accordingly, the source 114 may be a camera which can be any
of a standard color (RGB) camera. The source 114 may also be a
depth sensor. The source 114 may also be a laser scanning device.
In an embodiment, the source for generating the computer-readable
reconstruction of a subject, for example, a removed anatomical
feature and/or other portions of a being's anatomy may be any
combination of devices that are capable of generating
computer-readable reconstructions of the subject of interest.
Accordingly, such a combination may include an RGB camera and a
depth sensor, for example the Structure sensor, available from
Occipital, Inc., of San Francisco, Calif.). The combination may
also include a laser scanning device. In one embodiment, the source
is a camera attached the arm and the camera/arm may be moved to at
least one position from which an image of the subject of interest
is taken. In an embodiment, a computer-readable reconstruction of
the subject of interest, (an anatomical feature in FIG. 7) may be
generated and may be combined with positional information relative
to the base of the arm. The computer-readable reconstruction, i.e.,
each of the at least one picture/image/digital image, may be
stitched together using appropriate software, and may then be
registered to the patient/implant, and the region of interest (for
example a portion of the anatomical feature, or a geometry of the
anatomical feature such as a perimeter of a removed portion of
bone) is projected onto the implant. Accordingly, the process of
modifying the craniofacial implant for single-stage cranioplasty
(by following the projected geometry on the implant, for example,
removing portions of the implant according to the projected
geometry) can be dramatically reduced, thus decreasing total
operative time, limiting blood loss/morbidity, and improving final
outcomes.
[0066] Once registered, the patient's resected anatomy is digitized
and projected onto the CCI. The surgeon traces the resection with a
marking tool and shaves the implant to a precise fit on the
patient. For example, as shown in FIGS. 8A-9D, after tracing the
area of interest, such as a cut-region (i.e., an area of the
anatomy featuring the removed anatomical feature) and/or other
portions of a being's anatomy as illustrated in FIG. 6, or after
creating an image of the cut-region and/or other portions of a
being's anatomy via the use of a camera-based images (e.g., digital
images) and positional information, as described above for FIG. 7,
a visualization routine may be executed by computer 115-R. The
visualization routine may be software instructions executed by the
computer to generate a display of the computer-readable
reconstruction of the cut-region geometry over an oversized
CCI.
[0067] In one embodiment as shown in FIG. 8A, a first arrangement
800 for executing a visualization routine is shown. A projector 122
disposed on a stand 801 projects an image onto a surface of an
implant 120 from a pre-determined distance h defined by a height of
an arm 803. The image may be a virtual reconstruction 118 based on
a computer-readable reconstruction of the area of interest 112 of
the being's anatomy 108 as described above. That is, the virtual
reconstruction 118 is generated from a computer-readable
reconstruction of the area of interest that is created as discussed
above, onto the implant 120 itself (e.g., an oversized implant). An
alternative embodiment shown in FIG. 8B provides an arching stand
801' which may be attached to an operating room table. In an
embodiment, a projector 122 disposed on a stand 801' displays an
image onto a surface of an implant 120 from a pre-determined
distance h defined by a height of arches 803'. The image may be a
virtual reconstruction 118 based on a computer-readable
reconstruction of the area of interest 112 of the being's anatomy
108 as described above. For both FIGS. 8A-8B, the stands 801 and
801' may be attached to, for example, an operating table. The
stands 801, 801' may include sterile surfaces. Additionally, for
both FIGS. 8A-8B, the height from which the virtual reconstruction
is projected is known, and a thickness or height of the implant is
known, the projected virtual reconstruction can be provided
to-scale at substantially the dimensions of an anatomical feature
of interest as constructed according to the tracking method
described above.
[0068] FIGS. 9A-9D illustrates an example surgical method according
to an embodiment. In FIG. 9A, an anatomical feature of interest
(e.g., a defect) is identified. In an embodiment, the virtual
reconstruction 118 of the area of interest 112 may simply be a
trace that appears as colored lines 118' projected on the implant
as shown in FIG. 9B (which is a top view looking down in, for
example, FIGS. 8B from the projector 122 onto the implant 120). In
an embodiment, the virtual reconstruction 118 of the area of
interest may simply be a projected image of the patient's
anatomical feature (e.g., to scale) that the clinician can then use
to trace around with a marking pen 908 directly on the implant as
shown in FIG. 9C. In another embodiment, a virtual reconstruction
of the oversized implant (i.e., a computer-readable reconstruction
of the oversized implant) can be generated and accessed by the CAPE
system computer. A virtual implant generated by the projector 122
and the physical implant may be aligned by changing source 114
parameters (e.g., the model transformation) until the virtual model
exactly overlays the physical model. A surgeon may then use a
marking tool (e.g., sterile marking pen) to outline the projected
points (the trace from the anatomical feature of interest). The
surgeon then cuts excess material off of the CCI, for example along
the outline of the projected points, and fits the implant into
exact place on the patient as shown in FIG. 9D--in a less
time-intense, labor-intense manner. Significant time reduction (by
up to 90%) and improved implant-to-defect positioning (i.e., fewer
gaps between implant and surrounding bone) are both advantages of
at least one embodiment.
[0069] The methods, tools and systems described with respect to,
for example, FIGS. 7-9 may be included in a surgical method, such
as surgical method 1000 of FIG. 10 which can be executed for sizing
an implant to an anatomical feature. Surgical method 1000 may
include one or more of a registration 1002, a surgical procedure
1004, an implant modification 1006 and an implant attachment 1008.
For example, the surgical method 1000 may include registration 1002
which includes one or more of attaching a first reference unit
comprising a first trackable element at a location on a being's
anatomy at 1001, detecting a location of at least the reference
unit with a detector at 1003, accessing a computer-readable
reconstruction of the being's anatomy 1005, attaching a second
reference unit comprising a second trackable element to an implant
at 1007, detecting a location of at least the second trackable
element with a detector at 1009 and accessing a computer-readable
reconstruction of the implant at 1011. The surgical method 1000 may
include surgical procedure 1004 which includes one or more of
resecting a portion of the beings anatomy at 1013, tracing an
anatomical feature of interest with a pointer tool at 1015 and
detecting a location of the pointer tool with a detector at 1017.
The surgical method 1000 may include an implant modification 1006
which includes one or more of accessing a computer-readable
reconstruction of a trace at 1019, superimposing the
computer-readable reconstruction of the trace on the
computer-readable reconstruction of the implant at 1021, adjusting
a location of the computer-readable reconstruction of the trace
superimposed on the computer-readable reconstruction of the implant
at 1023, displaying the computer-readable reconstruction of the
trace at 1025, tracing the projected computer-readable
reconstruction of the trace on the implant with a marking tool at
1027, and removing excess material from the implant to form a
resized implant at 1029. The surgical method 1000 may include
implant attachment at 1007 which includes placing the resized
implant at an osteotomy site at 1031 (which may be the location
where the portion of the being's anatomy was resected at 1013) and
attaching the resized implant to the being's anatomy at 1033, which
may be done with plates, screws or a combination thereof.
[0070] The methods, tools and systems described with respect to,
for example, FIGS. 7-9 may be included in a surgical method, such
as surgical method 1100 of FIG. 11 which can be executed for sizing
an implant to an anatomical feature. Surgical method 1100 may
include one or more of a surgical procedure 1102, an implant
modification 1104 and an implant attachment 1106. The surgical
method 1100 may include surgical procedure 1102 which includes one
or more of resecting a portion of the beings anatomy at 1101,
tracing and generating a computer-readable reconstruction of the
being's anatomy at 1103. Surgical method 1100 may include implant
modification 1104 which includes accessing the computer-readable
reconstruction of the being's anatomy at 1105, displaying the at
least one computer-readable reconstruction of the being's anatomy
at 1107, superimposing the displayed computer-readable
reconstruction of the being's anatomy onto an implant at 1109,
tracing the displayed computer-readable reconstruction of the
being's anatomy on the implant with a marking tool at 1111, and
removing excess material from the implant to form a resized implant
at 1113. The surgical method 1100 may include implant attachment
1106 which includes placing the resized implant at an osteotomy
site at 1115 (which may be the location where the portion of the
being's anatomy was resected at 1101) and attaching the resized
implant to the being's anatomy at 1117, which may be done with
plates, screws or a combination thereof.
EXAMPLES
Example 1
Comparison Between Conventional Method ("Control Surgery--Cadaver
1) and a Method of the Embodiments ("Experimental Surgery--Cadaver
#2)
[0071] Identical defects were created on two male cadaver heads
(cadaver #1 and cadaver #2) to mimic skull neoplasm resection. For
cadaver #1, a conventional method for reducing the size of an
implant includes hand-drawing an outline for later drill shaving.
This conventional method required the surgeon to use his eyes and
hands to judge on where the implant requires modification in order
to fit the implant within the skull defect. While custom cranial
implants are beneficial, the conventional method required intra-op
modifications and in this particular instance took a total time of
around 35 minutes. The conventional method for modifying an
oversized custom-cranial implant resulted in suboptimal
bone-to-implant gaps (verified in 3D CT post-op scan image).
[0072] For cadaver #2, a method of an embodiment was used to modify
a CCI. A similar defect was created on cadaver #2 as was for
cadaver #1. CAPE system hardware, including a cranial mount and a
trackable position indicator were attached to the cadaver #2 for
intra-op assessment of exact defect size to guide real-time implant
modification. Fiducial registration was performed via an on-screen
image with a CT-scan that was preuploaded. The trackable components
of the CAPE system were tracked with an optical tracker (POLARIS).
A modified implant was formed, for example, according to a method
of an embodiment. A red light, corresponding to a geometry of a
trace as described above, was projected onto the implant for
guiding the surgeon on marking areas for further customization of
the implant. A sterile marking pen was used for outlining/marking
on the projected trace. Excess portions of the implant, defined by
those portions outside of a boundary of the outlined/marked trace,
were removed and the implant was attached onto the cadaver via
rigid fixation. This experimental surgery on Cadaver #2 required
only 3 minutes for total implant customization time and resulted in
acceptable bone-to implant gaps.
Example 2
Comparison Between Conventional Method ("Control Technique--Cadaver
#1) and Computer-Assisted Craniomaxillofacial Surgical Method of
the Embodiments ("Experimental Surgery--Cadavers #2-6)
[0073] A total of 6 single-stage cranioplasties with CCIs were
performed on cadaveric specimens obtained through the Maryland
State Anatomy Board. The first surgery on cadaver #1, served as the
control method, and was performed via standard technique which
required the surgeon to use his eyes and hands to judge the
locations of the implant that required modification in order to fit
the skull defect. For objective comparison, the next 5 experimental
surgeries (on cadavers #2-#6) utilized the novel computer-assisted
methods of the embodiments.
[0074] For the purpose of qualitative and quantitative
post-surgical analyses, pre- and post-operative CT scans were
obtained throughout the six experiments on all six cadavers; each
cadaver specimen underwent three CT scans each. A SOMATOM
Definition Flash (Siemens Healthcare; Germany) at
0.48.times.0.48.times.0.50 mm3 resolution was used to identify the
existing skeletal anatomy--and all scans were labeled either
"pre-defect", "pre-cranioplasty" or "post-cranioplasty". Of note,
varying skull defects were manually created simulating previous
skull tumors located around the anterior skull region. Automated
thresholding in Mimics (Materialise; Plymouth, Mich.) generated
surface models of each scan (n=5). From these post-trauma models,
oversized CCI' s were designed and printed using additive
manufacturing techniques for each of the six cadaver specimens. For
the conventional method, the CCI for cadaver #1 was trimmed using
"hand and eye guidance" only.
[0075] For the method of the embodiments, the surgeon (CRG)
registered each of the cadavers #2-#6 skulls intra-operatively and
digitized the respective defect outline following the methods
described in the above-embodiments and oncological resection.
Following digitization, an overhead projector displayed the
skeletal defect outline onto the implant (without any direct
contact risking contamination) using a thin laser and red beam of
light, which then allowed the surgeon to trace the irregular
borderline with a sterile marking pen. For all six cases, the
implant was cut to size using a handheld burr and attached to the
specimen's skeleton with standard fixation plates and screws. The
operations were timed in segments, including the reference fixation
and implant modification times. Post-operative CT scans of the
specimens recorded the final outcome for both quantitative and
qualitative analyses.
[0076] Commercial image processing software--Amira (Visualization
Sciences Group; Burlington, Mass.)--provided segmentation and
visualization for post-hoc analysis of all six CCI cranioplasties.
Registration using normalized mutual information in Amira aligned
the pre-operative and post-defect CT volumes together. A binary
masking operation between manually labeled volumes of the "pre-op"
and "pre-cranioplasty" CT scans was performed to identify the true
defect size and shape. After aligning the post-operative CT volumes
to the pre-operative volumes, a threshold-based segmentation with
manual refinement separated the implants from the bone on all
post-operative scans. The Amira software was used to generate
surface models of the corresponding implants and the defects. Since
implant thickness did not match skull thickness, only the "top"
surfaces of each model were considered. A distance map measured the
similarity between the implants and defects by identifying the
closest point on the implant for each vertex of the defect
surface.
[0077] The conventional method and the method of the embodiments
were quantified objectively with "total time saved" and "total time
used" through various parts of the surgeries (n=6). The "standard
control method" required around 35 minutes for intra-op
modification, which is highly consistent with average times
reported in the literature for single-stage CCI reconstruction.
More importantly, the labor-intense "control method" also resulted
in suboptimal bone-to-implant gaps at the perimeter of the tumor
defect. The conventional method's inaccuracy was demonstrated on a
post-cranioplasty 3D CT scan image. In contrast, all five
experimental surgeries (n=5) performed according the surgical
methods of the embodiments showed significant time reduction and
improved accuracy--with stepwise success as the study progressed
during a nine month time span. Most notably, the experimental
surgeries performed according to methods of the embodiments using
computer-assistance (i.e., surgeries for Cadavers #2-6) required,
on average, only 3-4 minutes in total for implant
customization--which is a staggering time reduction of around
90-95%. More impressively, minimized bone-to implant gaps were
observed, which equates to an improved cranial reconstruction and
aesthetic result.
[0078] Implants resized according to the methods of the embodiments
fit very well in their respective defect, with improved positioning
as compared to the control/conventional method. For example, all
cadavers #2-#6 showed that the entire top surface of the implant
was placed properly within about 1 mm, on average, of the original
skull defect. Actual results are shown in Table 1 for all
surgeries.
TABLE-US-00001 TABLE 1 Cadaver ID 2 3 4 5 6 Mean Timing (sec) Ref
144 270 120 124 124 156.4 mounting Registration + 140 135 160 106
180 144.2 tracing Implant 80 61 n/a 35.6 60 59.2 tracing Cutting
460 435 n/a 126 217.6 309.7 Mount Removal 48 48 48 Total 824 901
280 439.6 629.6 614.8 Software Time 60 60 (sec) Distance on Mean
1.06 0.74 0.92 0.98 1.28 0.996 defect (mm) Std 1.33 0.67 0.48 1.16
1.40 Max 10.29 4.79 2.46 8.07 8.39 Distance on Mean 0.74 0.67 0.92
0.52 0.68 0.706 implant (mm) Std 0.60 0.62 0.48 0.40 0.53 Max 2.98
4.99 2.46 2.65 3.85 Surface Area Initial 14263.90 12431.50 20081.30
18379.90 22003.30 17431.38 (mm2) Final 7682.58 5523.24 8129.26
6504.21 7491.27 7066.11 Intraop Mean 1.49 0.25 0.31 0.76 0.65 0.692
Registration (m) Std 1.14 0.19 0.28 0.58 0.39 Max 4.66 0.87 1.80
2.89 1.96 Notes Revision Revision Revision No revision No
revision
[0079] In summary, the surgeries performed according to the
surgical methods of the embodiments showed unequivocal success in
achieving its milestones, by drastically reducing the time
necessary for single-stage cranioplasty reconstruction, and at the
same time, significantly improving the implant modification for an
ideal fit.
[0080] As used herein, to the extent that the terms "coupled,"
"connected," and "connecting", or variants thereof are used in
either the detailed description and the claims, such terms are
intended to refer to "in direct connection with" or "in connection
with via one or more intermediate elements or members." As used
herein, to the extent that the terms "including", "includes",
"having", "has", "with", or variants thereof are used in either the
detailed description and the claims, such terms are intended to be
inclusive in a manner similar to the term "comprising." As used
herein, the phrase "at least one of" or "one or more of", for
example, A, B, and C means any of the following: either A, B, or C
alone; or combinations of two, such as A and B, B and C, and A and
C; or combinations of three A, B and C.
[0081] Other embodiments will be apparent to those skilled in the
art from consideration of the specification and practice of the
examples disclosed herein. It is intended that the specification
and examples be considered as exemplary only, with a true scope and
spirit of the embodiments being indicated by the following
claims.
* * * * *
References