U.S. patent application number 15/415414 was filed with the patent office on 2017-05-25 for soft body automatic registration and surgical monitoring system.
The applicant listed for this patent is Navigate Surgical Technologies, Inc.. Invention is credited to Ehud (Udi) DAON.
Application Number | 20170143431 15/415414 |
Document ID | / |
Family ID | 48427604 |
Filed Date | 2017-05-25 |
United States Patent
Application |
20170143431 |
Kind Code |
A1 |
DAON; Ehud (Udi) |
May 25, 2017 |
SOFT BODY AUTOMATIC REGISTRATION AND SURGICAL MONITORING SYSTEM
Abstract
A surgical hardware and software monitoring system and method
allows for surgical planning while the patient is available for
surgery, for example while the patient is being prepared for
surgery so that the system may model the surgical site. In one
embodiment, the model may be used to track contemplated surgical
procedures and warn the physician regarding possible boundary
violations that would indicate an inappropriate location in a
surgical procedure. In another embodiment, the monitoring system
may track the movement of instruments during the procedure and in
reference to the model to enhance observation of the procedure. In
a further embodiment the monitoring system can be used to model and
track the changes in the surgical site itself.
Inventors: |
DAON; Ehud (Udi); (North
Vancouver, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Navigate Surgical Technologies, Inc. |
Vancouver |
|
CA |
|
|
Family ID: |
48427604 |
Appl. No.: |
15/415414 |
Filed: |
January 25, 2017 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
13745762 |
Jan 19, 2013 |
9554763 |
|
|
15415414 |
|
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 1/00 20130101; A61B
2090/3983 20160201; G06F 19/321 20130101; A61B 6/12 20130101; A61C
1/082 20130101; A61B 6/145 20130101; A61C 3/02 20130101; A61B 90/39
20160201; A61B 6/467 20130101; G06F 19/3481 20130101; A61B 6/032
20130101; A61B 34/20 20160201; G16H 20/40 20180101; A61B 10/0233
20130101; G16H 30/20 20180101; A61B 2034/2065 20160201; G16H 50/50
20180101; H04L 67/42 20130101; A61B 6/14 20130101; A61B 6/481
20130101; A61B 2090/3966 20160201 |
International
Class: |
A61B 34/20 20060101
A61B034/20; A61B 6/12 20060101 A61B006/12; G06F 19/00 20060101
G06F019/00; A61B 90/00 20060101 A61B090/00; A61C 1/08 20060101
A61C001/08; A61C 3/02 20060101 A61C003/02; A61B 6/03 20060101
A61B006/03; A61B 6/14 20060101 A61B006/14 |
Claims
1. A method for real time monitoring the position of an object in
relation to a surgical site of a patient, the method comprising the
steps of: removably attaching a fiducial reference to a fiducial
location on the patient proximate the surgical site; performing a
scan with the fiducial reference attached to a fiducial location to
obtain scan data; determining the three-dimensional location and
orientation of the fiducial reference from the scan data; obtaining
real time image information of the surgical site; determining in
real time the three-dimensional location and orientation of the
fiducial reference from the image information; deriving a spatial
transformation matrix for expressing in real time the
three-dimensional location and orientation of the fiducial
reference as determined from image information in terms of the
three-dimensional location and orientation of the fiducial
reference as determined from scan data; determining in real time
the three-dimensional location and orientation of the object from
the image information; and relating the three-dimensional location
and orientation of the object to the three-dimensional location and
orientation of the fiducial reference as determined from the image
information.
2. The surgical monitoring method of claim 1 wherein the fiducial
reference is configured in at least one of marked and shaped for
having at least one of its location and its orientation determined
from the scan data.
3. The surgical monitoring method of claim 1 wherein the fiducial
reference is configured in at least one of marked and shaped to
allow the fiducial reference to be uniquely identified from the
scan data.
4. The surgical monitoring method of claim 1 further comprising a
tracking marker in fixed three-dimensional spatial relationship
with the fiducial reference, wherein the tracking marker is
configured for having at least one of its location and its
orientation determinable based on the image information and the
scan data.
5. The surgical monitoring method of claim 4 further comprising a
first tracking pole, wherein the tracking marker is configured to
be removably and rigidly connected to the fiducial reference by the
first tracking pole.
6. The surgical monitoring method of claim 5 wherein that the first
tracking pole has a three-dimensional structure uniquely
identifiable by the controller from the image information.
7. The surgical monitoring method of claim 5 wherein the first
tracking pole has a three-dimensional structure allowing for
three-dimensional orientation to be determinable from image
information.
8. The surgical monitoring method of claim 5 wherein the first
tracking pole and fiducial reference are configured to allow the
first tracking pole to connect to a single unique location on the
fiducial reference in a first single unique three-dimensional
orientation.
9. The surgical monitoring method of claim 5 wherein the fiducial
reference is configured for the attachment in a single second
unique three-dimensional orientation of at least a second tracking
pole attached to a second tracking marker.
10. The surgical monitoring method of claim 5 wherein the first
tracking marker has a three-dimensional shape uniquely identifiable
by the controller from image information.
11. A method for tracking in real time changes in a surgical site,
the method comprising the steps of: removably attaching a
multi-element fiducial reference to a fiducial location on the
patient body proximate the surgical site, the multi-element
fiducial reference comprising a plurality of pattern segments
individually locatable based on scan data; performing a scan with
the fiducial reference attached to the fiducial location to obtain
the scan data; determining the three-dimensional locations and
orientations of at least a selection of the pattern segments based
on the scan data; obtaining real time image information of the
surgical site; determining in real time the three-dimensional
locations and orientations of the at least a selection of the
pattern segments from the image information; and deriving in real
time the spatial distortion of the surgical site by comparing in
real time the three-dimensional locations and orientations of the
at least a selection of the pattern segments as determined from the
image information with the three-dimensional locations and
orientations of the at least a selection of the pattern segments as
determined from the scan data.
12. The surgical tracking method of claim 11 wherein the marker
pattern includes a multi-element fiducial pattern comprising a
plurality of pattern segments and every one of said plurality of
segments is individually configured for having a segmental
three-dimensional location and orientation determinable based on
scan data of the surgical site, and for having the segmental
three-dimensional location and orientation determinable based on
image information about the surgical site.
13. The surgical tracking method of claim 12 wherein the plurality
of pattern segments have unique differentiable shapes that allow
the determining step to identify them uniquely from at least one of
scan data and image information.
14. The surgical tracking method of claim 12 further comprising
tracking markers attached to at least a selection of the pattern
segments, the tracking markers having at least one of identifying
marks and orientation marks that allow their three-dimensional
orientations to be determined by the controller from the image
information.
15. The surgical monitoring system of claim 12 wherein the
determining step further calculates the locations of anatomical
features in the proximity of the multi-element fiducial
pattern.
16. The surgical tracking method of claim 12 further comprising
tracking markers attached to at least a selection of the pattern
segments, the tracking markers having at least one of identifying
marks and orientation marks that allow their three-dimensional
orientations to be determinable from the image information.
17. The surgical monitoring system of claim 14 wherein the
determining step finds the locations and orientations of at least a
selection of the pattern segments based on image information and
scan data.
18. The surgical monitoring system of claim 14 wherein the
determining step further calculates the locations of anatomical
features in the proximity of the multi-element fiducial pattern.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present Application is a Divisional of U.S. patent
application Ser. No. 13/745,762, filed on Jan. 1, 2013, now U.S.
Pat. No. 9,554,763, issued Jan. 31, 2017; and claims priority under
35 U.S.C. .sctn.119(e) of U.S. Provisional Patent Application Ser.
No. 61/616,673, filed on Mar. 28, 2012 and titled "Soft Body
Automatic Registration and Surgical Monitoring System"; and claims
priority from PCT International Patent Application which designates
the United States Serial No. PCT/IL2012/000363, filed on Oct. 21,
2012, U.S. Non-Provisional patent application Ser. No. 13/571,284,
filed on Aug. 9, 2012, and which claims priority from U.S.
Provisional Patent Application Ser. Nos. 61/553,058 and 61/616,718
filed on Oct. 28, 2011, and Mar. 28, 2012 respectively, said PCT,
Non-Provisional and Provisional applications all entitled "SURGICAL
LOCATION MONITORING SYSTEM AND METHOD"; the disclosures of all of
which are expressly incorporated by reference herein.
BACKGROUND OF THE INVENTION
[0002] Field of the Invention
[0003] The invention relates to location monitoring hardware and
software systems. More specifically, the field of the invention is
that of surgical equipment and software for monitoring surgical
conditions.
[0004] Description of the Related Art
[0005] Visual and other sensory systems are known, with such
systems being capable of both observing and monitoring surgical
procedures. With such observation and monitoring systems, computer
aided surgeries are now possible, and in fact are being routinely
performed. In such procedures, the computer software interacts with
both clinical images of the patient and observed surgical images
from the current surgical procedure to provide guidance to the
physician in conducting the surgery. For example, in one known
system a carrier assembly bears at least one fiducial marker onto
an attachment element in a precisely repeatable position with
respect to a patient's jaw bone, employing the carrier assembly for
providing registration between the fiducial marker and the
patient's jaw bone and implanting the tooth implant by employing a
tracking system which uses the registration to guide a drilling
assembly. With this relatively new computer implemented technology,
further improvements may further advance the effectiveness of
surgical procedures.
SUMMARY OF THE INVENTION
[0006] The present invention is a surgical hardware and software
monitoring system and method which allows for surgical planning
while the patient is available for surgery, for example while the
patient is being prepared for surgery so that the system may model
the surgical site. In one embodiment, the model may be used to
track contemplated surgical procedures and warn the physician
regarding possible boundary violations that would indicate an
inappropriate location in a surgical procedure. In another
embodiment, the hardware may track the movement of instruments
during the procedure and in reference to the model to enhance
observation of the procedure. In this way, physicians are provided
an additional tool to improve surgical planning and
performance.
[0007] The system uses a particularly configured fiducial
reference, to orient the monitoring system with regard to the
critical area. The fiducial reference is attached to a location
near the intended surgical area. For example, in the example of a
dental surgery, a splint may be used to securely locate the
fiducial reference near the surgical area. The fiducial reference
may then be used as a point of reference, or a fiducial, for the
further image processing of the surgical site. The fiducial
reference may be identified relative to other portions of the
surgical area by having a recognizable fiducial marker apparent in
the scan.
[0008] The system of embodiments of the invention involves
automatically computing the three-dimensional location of the
patient by means of a tracking device that may be a tracking
marker. The tracking marker may be attached in fixed spatial
relation either directly to the fiducial reference, or attached to
the fiducial reference via a tracking pole that itself may have a
distinct three-dimensional shape. In the dental surgery example, a
tracking pole is mechanically connected to the base of the fiducial
reference that is in turn fixed in the patient's mouth. Each
tracking pole device has a particular observation pattern, located
either on itself or on a suitable tracking marker, and a particular
geometrical connection to the base, which the computer software
recognizes as corresponding to a particular geometry for subsequent
location calculations. Although individual tracking pole devices
have distinct configurations, they may all share the same
connection base and thus may be used with any keyucial reference.
The particular tracking information calculations are dictated by
the particular pole tng pole used, and actual patient location is
calculated accordingly. Thus, pole trackine devices may be
interchanged and calculation of the location remains the same. This
provides, in the case of dental surgery, automatic recognition of
the patient head location in space. Alternatively, a sensor device,
or a tracker, may be in a known position relative to the fiducial
key and its tracking pole, so that the current data image may be
mapped to the scan image items.
[0009] The fiducial reference and each tracking pole or associated
tracking marker may have a pattern made of radio opaque material so
that when imaging information is scanned by the software, the
particular items are recognized. Typically, each instrument used in
the procedure has a unique pattern on its associated tracking
marker so that the tracker information identifies the instrument.
The software creates a model of the surgical site, in one
embodiment a coordinate system, according to the location and
orientation of the patterns on the fiducial reference and/or
tracking pole(s) or their attached tracking markers. By way of
example, in the embodiment where the fiducial reference has an
associated pre-assigned pattern, analysis software interpreting
image information from the tracker may recognize the pattern and
may select the site of the base of the fiducial to be at the
location where the fiducial reference is attached to a splint. If
the fiducial key does not have an associated pattern, a fiducial
site is designated. In the dental example this can be at a
particular spatial relation to the tooth, and a splint location can
be automatically designed for placement of the fiducial
reference.
[0010] In a first aspect of the invention there is provided a
surgical monitoring system comprising a fiducial reference
configured for removably attaching to a location proximate a
surgical site, for having a three-dimensional location and
orientation determinable based on scan data of the surgical site,
and for having the three-dimensional location and orientation
determinable based on image information about the surgical site; a
tracker arranged for obtaining the image information; and a
controller configured for spatially relating the image information
to the scan data and for determining the three-dimensional location
and orientation of the fiducial reference. In one embodiment of the
invention the fiducial reference may be rigidly and removably
attachable to a part of the surgical site. In such an embodiment
the fiducial reference may be repeatably attachable in the same
three-dimensional orientation to the same location on the
particular part of the surgical site.
[0011] The fiducial reference is at least one of marked and shaped
for having at least one of its location and its orientation
determined from the scan data and to allow it to be uniquely
identified from the scan data. The surgical monitoring system
further comprises a first tracking marker in fixed
three-dimensional spatial relationship with the fiducial reference,
wherein the first tracking marker is configured for having at least
one of its location and its orientation determined by the
controller based on the image information and the scan data. The
first tracking marker may be configured to be removably and rigidly
connected to the fiducial reference by a first tracking pole. The
first tracking pole can have a three-dimensional structure uniquely
identifiable by the controller from the image information. The
three-dimensional structure of the first tracking pole allows its
three-dimensional orientation of the first tracking pole to be
determined by the controller from the image information.
[0012] The first tracking pole and fiducial reference may be
configured to allow the first tracking pole to connect to a single
unique location on the fiducial reference in a first single unique
three-dimensional orientation. The fiducial reference may be
configured for the attachment in a single second unique
three-dimensional orientation of at least a second tracking pole
attached to a second tracking marker. The first tracking marker may
have a three-dimensional shape that is uniquely identifiable by the
controller from the image information. The first tracking marker
can have a three-dimensional shape that allows its
three-dimensional orientation to be determined by the controller
from the image information. The first tracking marker may have a
marking that is uniquely identifiable by the controller and the
marking may be configured for allowing at least one of its location
and its orientation to be determined by the controller based on the
image information and the scan data.
[0013] The fiducial reference may be a multi-element fiducial
pattern comprising a plurality of pattern segments and every
segment is individually configured for having a segmental
three-dimensional location and orientation determinable based on
scan data of the surgical site, and for having the segmental
three-dimensional location and orientation determinable based on
image information about the surgical site. The plurality of pattern
segments can have unique differentiable shapes that allow the
controller to identify them uniquely from at least one of the scan
data and the image information. Tracking markers canmay attached to
at least a selection of the pattern segments, the tracking markers
having at least one of identifying marks and orientation marks that
allow their three-dimensional orientations to be determined by the
controller from the image information. The controller may be
configured for determining the locations and orientations of at
least a selection of the pattern segments based on the image
information and the scan data. The controller may be configured for
calculating of the locations of anatomical features in the
proximity of the multi-element fiducial pattern.
[0014] The surgical monitoring system may comprise further tracking
markers attached to implements proximate the surgery site and the
controller may be configured for determining locations and
orientations of the implements based on the image information and
information about the further tracking markers.
[0015] In another aspect of the invention there is provided a
method for relating in real time the three-dimensional location and
orientation of a surgical site on a patient to the location and
orientation of the surgical site in a scan of the surgical site,
the method comprising removably attaching a fiducial reference to a
fiducial location on the patient proximate the surgical site;
performing the scan with the fiducial reference attached to the
fiducial location to obtain scan data; determining the
three-dimensional location and orientation of the fiducial
reference from the scan data; obtaining real time image information
of the surgical site; determining in real time the
three-dimensional location and orientation of the fiducial
reference from the image information; deriving a spatial
transformation matrix for expressing in real time the
three-dimensional location and orientation of the fiducial
reference as determined from the image information in terms of the
three-dimensional location and orientation of the fiducial
reference as determined from the scan data.
[0016] The obtaining of real time image information of the surgical
site may comprise rigidly and removably attaching to the fiducial
reference a first tracking marker in a fixed three-dimensional
spatial relationship with the fiducial reference. The first
tracking marker may be configured for having its location and its
orientation determined based on the image information. The
attaching of the first tracking marker to the fiducial reference
may comprise rigidly and removably attaching the first tracking
marker to the fiducial reference by means of a tracking pole. The
obtaining of the real time image information of the surgical site
may comprise rigidly and removably attaching to the fiducial
reference a tracking pole in a fixed three-dimensional spatial
relationship with the fiducial reference, and the tracking pole may
have a distinctly identifiable three-dimensional shape that allows
its location and orientation to be uniquely determined from the
image information. In the case where the fiducial reference is a
multi-element fiducial pattern comprising a plurality of pattern
segments individually locatable based on the scan data, the
determining of the three-dimensional location and orientation of
the fiducial reference from the scan data may comprise determining
the three-dimensional location and orientation of at least a
selection of the plurality of pattern segments from the scan data;
and the determining in real time the three-dimensional location and
orientation of the fiducial reference from the image information
may comprise determining the three-dimensional location and
orientation of the at least a selection of the plurality of pattern
segments from the image information.
[0017] In another aspect of the invention there is provided a
method for tracking in real time changes in a surgical site, the
method comprising removably attaching a multi-element fiducial
reference to a fiducial location on the patient proximate the
surgical site, the multi-element fiducial reference comprising a
plurality of pattern segments individually locatable based on scan
data; performing a scan with the fiducial reference attached to the
fiducial location to obtain the scan data; determining the
three-dimensional locations and orientations of at least a
selection of the pattern segments from the scan data; obtaining
real time image information of the surgical site; determining in
real time the three-dimensional locations and orientations of the
at least a selection of the pattern segments from the image
information; and deriving in real time the spatial distortion of
the surgical site by comparing in real time the three-dimensional
locations and orientations of the at least a selection of the
pattern segments as determined from the image information with the
three-dimensional locations and orientations of the at least a
selection of the pattern segments as determined from the scan
data.
[0018] In yet a further aspect of the invention there is provided a
method for real time monitoring the position of an object in
relation to a surgical site of a patient, the method comprising
removably attaching a fiducial reference to a fiducial location on
the patient proximate the surgical site; performing a scan with the
fiducial reference attached to the fiducial location to obtain scan
data; determining the three-dimensional location and orientation of
the fiducial reference from the scan data; obtaining real time
image information of the surgical site; determining in real time
the three-dimensional location and orientation of the fiducial
reference from the image information; deriving a spatial
transformation matrix for expressing in real time the
three-dimensional location and orientation of the fiducial
reference as determined from the image information in terms of the
three-dimensional location and orientation of the fiducial
reference as determined from the scan data; determining in real
time the three-dimensional location and orientation of the object
from the image information; and relating the three-dimensional
location and orientation of the object to the three-dimensional
location and orientation of the fiducial reference as determined
from the image information. The determining in real time of the
three-dimensional location and orientation of the object from the
image information may comprise rigidly attaching a tracking marker
to the object.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The above mentioned and other features and objects of this
invention, and the manner of attaining them, will become more
apparent and the invention itself will be better understood by
reference to the following description of an embodiment of the
invention taken in conjunction with the accompanying drawings,
wherein:
[0020] FIG. 1 is a schematic diagrammatic view of a network system
in which embodiments of the present invention may be utilized.
[0021] FIG. 2 is a block diagram of a computing system (either a
server or client, or both, as appropriate), with optional input
devices (e.g., keyboard, mouse, touch screen, etc.) and output
devices, hardware, network connections, one or more processors, and
memory/storage for data and modules, etc. which may be utilized as
controller and display in conjunction with embodiments of the
present invention.
[0022] FIGS. 3A-J are drawings of hardware components of the
surgical monitoring system according to embodiments of the
invention.
[0023] FIGS. 4A-C is a flow chart diagram illustrating one
embodiment of the registering method of the present invention.
[0024] FIG. 5 is a drawing of a dental fiducial key with a tracking
pole and a dental drill according to one embodiment of the present
invention.
[0025] FIG. 6 is a drawing of an endoscopic surgical site showing
the fiducial key, endoscope, and biopsy needle according to another
embodiment of the invention.
[0026] FIGS. 7A and 7B are drawings of a multi-element fiducial
pattern comprising a plurality of pattern segments in respectively
a default condition and a condition in which the body of a patient
has moved to change the mutual spatial relation of the pattern
segments.
[0027] FIGS. 8A-C is a flow chart diagram illustrating one
embodiment of the registering method of the present invention as
applied to the multi-element fiducial pattern of FIGS. 7A and
7B.
[0028] Corresponding reference characters indicate corresponding
parts throughout the several views. Although the drawings represent
embodiments of the present invention, the drawings are not
necessarily to scale and certain features may be exaggerated in
order to better illustrate and explain the present invention. The
flow charts and screen shots are also representative in nature, and
actual embodiments of the invention may include further features or
steps not shown in the drawings. The exemplification set out herein
illustrates an embodiment of the invention, in one form, and such
exemplifications are not to be construed as limiting the scope of
the invention in any manner.
DESCRIPTION OF EMBODIMENTS OF THE PRESENT INVENTION
[0029] The embodiments disclosed below are not intended to be
exhaustive or limit the invention to the precise form disclosed in
the following detailed description. Rather, the embodiments are
chosen and described so that others skilled in the art may utilize
their teachings.
[0030] The detailed descriptions that follow are presented in part
in terms of algorithms and symbolic representations of operations
on data bits within a computer memory representing alphanumeric
characters or other information. The hardware components are shown
with particular shapes and relative orientations and sizes using
particular scanning techniques, although in the general case one of
ordinary skill recognizes that a variety of particular shapes and
orientations and scanning methodologies may be used within the
teaching of the present invention. A computer generally includes a
processor for executing instructions and memory for storing
instructions and data, including interfaces to obtain and process
imaging data. When a general-purpose computer has a series of
machine encoded instructions stored in its memory, the computer
operating on such encoded instructions may become a specific type
of machine, namely a computer particularly configured to perform
the operations embodied by the series of instructions. Some of the
instructions may be adapted to produce signals that control
operation of other machines and thus may operate through those
control signals to transform materials far removed from the
computer itself. These descriptions and representations are the
means used by those skilled in the art of data processing arts to
most effectively convey the substance of their work to others
skilled in the art.
[0031] An algorithm is here, and generally, conceived to be a
self-consistent sequence of steps leading to a desired result.
These steps are those requiring physical manipulations of physical
quantities, observing and measuring scanned data representative of
matter around the surgical site. Usually, though not necessarily,
these quantities take the form of electrical or magnetic pulses or
signals capable of being stored, transferred, transformed,
combined, compared, and otherwise manipulated. It proves convenient
at times, principally for reasons of common usage, to refer to
these signals as bits, values, symbols, characters, display data,
terms, numbers, or the like as a reference to the physical items or
manifestations in which such signals are embodied or expressed to
capture the underlying data of an image. It should be borne in
mind, however, that all of these and similar terms are to be
associated with the appropriate physical quantities and are merely
used here as convenient labels applied to these quantities.
[0032] Some algorithms may use data structures for both inputting
information and producing the desired result. Data structures
greatly facilitate data management by data processing systems, and
are not accessible except through sophisticated software systems.
Data structures are not the information content of a memory, rather
they represent specific electronic structural elements that impart
or manifest a physical organization on the information stored in
memory. More than mere abstraction, the data structures are
specific electrical or magnetic structural elements in memory,
which simultaneously represent complex data accurately, often data
modeling physical characteristics of related items, and provide
increased efficiency in computer operation.
[0033] Further, the manipulations performed are often referred to
in terms, such as comparing or adding, commonly associated with
mental operations performed by a human operator. No such capability
of a human operator is necessary, or desirable in most cases, in
any of the operations described herein that form part of the
present invention; the operations are machine operations. Useful
machines for performing the operations of the present invention
include general-purpose digital computers or other similar devices.
In all cases the distinction between the method operations in
operating a computer and the method of computation itself should be
recognized. The present invention relates to a method and apparatus
for operating a computer in processing electrical or other (e.g.,
mechanical, chemical) physical signals to generate other desired
physical manifestations or signals. The computer operates on
software modules, which are collections of signals stored on a
media that represents a series of machine instructions that enable
the computer processor to perform the machine instructions that
implement the algorithmic steps. Such machine instructions may be
the actual computer code the processor interprets to implement the
instructions, or alternatively may be a higher level coding of the
instructions that is interpreted to obtain the actual computer
code. The software module may also include a hardware component,
wherein some aspects of the algorithm are performed by the
circuitry itself rather as a result of an instruction.
[0034] The present invention also relates to an apparatus for
performing these operations. This apparatus may be specifically
constructed for the required purposes or it may comprise a
general-purpose computer as selectively activated or reconfigured
by a computer program stored in the computer. The algorithms
presented herein are not inherently related to any particular
computer or other apparatus unless explicitly indicated as
requiring particular hardware. In some cases, the computer programs
may communicate or relate to other programs or equipments through
signals configured to particular protocols, which may or may not
require specific hardware or programming to interact. In
particular, various general-purpose machines may be used with
programs written in accordance with the teachings herein, or it may
prove more convenient to construct more specialized apparatus to
perform the required method steps. The required structure for a
variety of these machines will appear from the description
below.
[0035] The present invention may deal with "object-oriented"
software, and particularly with an "object-oriented" operating
system. The "object-oriented" software is organized into "objects",
each comprising a block of computer instructions describing various
procedures ("methods") to be performed in response to "messages"
sent to the object or "events" which occur with the object. Such
operations include, for example, the manipulation of variables, the
activation of an object by an external event, and the transmission
of one or more messages to other objects. Often, but not
necessarily, a physical object has a corresponding software object
that may collect and transmit observed data from the physical
device to the software system. Such observed data may be accessed
from the physical object and/or the software object merely as an
item of convenience; therefore where "actual data" is used in the
following description, such "actual data" may be from the
instrument itself or from the corresponding software object or
module.
[0036] Messages are sent and received between objects having
certain functions and knowledge to carry out processes. Messages
are generated in response to user instructions, for example, by a
user activating an icon with a "mouse" pointer generating an event.
Also, messages may be generated by an object in response to the
receipt of a message. When one of the objects receives a message,
the object carries out an operation (a message procedure)
corresponding to the message and, if necessary, returns a result of
the operation. Each object has a region where internal states
(instance variables) of the object itself are stored and where the
other objects are not allowed to access. One feature of the
object-oriented system is inheritance. For example, an object for
drawing a "circle" on a display may inherit functions and knowledge
from another object for drawing a "shape" on a display.
[0037] A programmer "programs" in an object-oriented programming
language by writing individual blocks of code each of which creates
an object by defining its methods. A collection of such objects
adapted to communicate with one another by means of messages
comprises an object-oriented program. Object-oriented computer
programming facilitates the modeling of interactive systems in that
each component of the system may be modeled with an object, the
behavior of each component being simulated by the methods of its
corresponding object, and the interactions between components being
simulated by messages transmitted between objects.
[0038] An operator may stimulate a collection of interrelated
objects comprising an object-oriented program by sending a message
to one of the objects. The receipt of the message may cause the
object to respond by carrying out predetermined functions, which
may include sending additional messages to one or more other
objects. The other objects may in turn carry out additional
functions in response to the messages they receive, including
sending still more messages. In this manner, sequences of message
and response may continue indefinitely or may come to an end when
all messages have been responded to and no new messages are being
sent. When modeling systems utilizing an object-oriented language,
a programmer need only think in terms of how each component of a
modeled system responds to a stimulus and not in terms of the
sequence of operations to be performed in response to some
stimulus. Such sequence of operations naturally flows out of the
interactions between the objects in response to the stimulus and
need not be preordained by the programmer.
[0039] Although object-oriented programming makes simulation of
systems of interrelated components more intuitive, the operation of
an object-oriented program is often difficult to understand because
the sequence of operations carried out by an object-oriented
program is usually not immediately apparent from a software listing
as in the case for sequentially organized programs. Nor is it easy
to determine how an object-oriented program works through
observation of the readily apparent manifestations of its
operation. Most of the operations carried out by a computer in
response to a program are "invisible" to an observer since only a
relatively few steps in a program typically produce an observable
computer output.
[0040] In the following description, several terms that are used
frequently have specialized meanings in the present context. The
term "object" relates to a set of computer instructions and
associated data, which may be activated directly or indirectly by
the user. The terms "windowing environment", "running in windows",
and "object oriented operating system" are used to denote a
computer user interface in which information is manipulated and
displayed on a video display such as within bounded regions on a
raster scanned video display. The terms "network", "local area
network", "LAN", "wide area network", or "WAN" mean two or more
computers that are connected in such a manner that messages may be
transmitted between the computers. In such computer networks,
typically one or more computers operate as a "server", a computer
with large storage devices such as hard disk drives and
communication hardware to operate peripheral devices such as
printers or modems. Other computers, termed "workstations", provide
a user interface so that users of computer networks may access the
network resources, such as shared data files, common peripheral
devices, and inter-workstation communication. Users activate
computer programs or network resources to create "processes" which
include both the general operation of the computer program along
with specific operating characteristics determined by input
variables and its environment. Similar to a process is an agent
(sometimes called an intelligent agent), which is a process that
gathers information or performs some other service without user
intervention and on some regular schedule. Typically, an agent,
using parameters typically provided by the user, searches locations
either on the host machine or at some other point on a network,
gathers the information relevant to the purpose of the agent, and
presents it to the user on a periodic basis.
[0041] The term "desktop" means a specific user interface which
presents a menu or display of objects with associated settings for
the user associated with the desktop. When the desktop accesses a
network resource, which typically requires an application program
to execute on the remote server, the desktop calls an Application
Program Interface, or "API", to allow the user to provide commands
to the network resource and observe any output. The term "Browser"
refers to a program which is not necessarily apparent to the user,
but which is responsible for transmitting messages between the
desktop and the network server and for displaying and interacting
with the network user. Browsers are designed to utilize a
communications protocol for transmission of text and graphic
information over a worldwide network of computers, namely the
"World Wide Web" or simply the "Web". Examples of Browsers
compatible with the present invention include the Internet Explorer
program sold by Microsoft Corporation (Internet Explorer is a
trademark of Microsoft Corporation), the Opera Browser program
created by Opera Software ASA, or the Firefox browser program
distributed by the Mozilla Foundation (Firefox is a registered
trademark of the Mozilla Foundation). Although the following
description details such operations in terms of a graphic user
interface of a Browser, the present invention may be practiced with
text based interfaces, or even with voice or visually activated
interfaces, that have many of the functions of a graphic based
Browser.
[0042] Browsers display information, which is formatted in a
Standard Generalized Markup Language ("SGML") or a HyperText Markup
Language ("HTML"), both being scripting languages, which embed
non-visual codes in a text document through the use of special
ASCII text codes. Files in these formats may be easily transmitted
across computer networks, including global information networks
like the Internet, and allow the Browsers to display text, images,
and play audio and video recordings. The Web utilizes these data
file formats to conjunction with its communication protocol to
transmit such information between servers and workstations.
Browsers may also be programmed to display information provided in
an eXtensible Markup Language ("XML") file, with XML files being
capable of use with several Document Type Definitions ("DTD") and
thus more general in nature than SGML or HTML. The XML file may be
analogized to an object, as the data and the stylesheet formatting
are separately contained (formatting may be thought of as methods
of displaying information, thus an XML file has data and an
associated method).
[0043] The terms "personal digital assistant" or "PDA", as defined
above, means any handheld, mobile device that combines computing,
telephone, fax, e-mail and networking features. The terms "wireless
wide area network" or "WWAN" mean a wireless network that serves as
the medium for the transmission of data between a handheld device
and a computer. The term "synchronization" means the exchanging of
information between a first device, e.g. a handheld device, and a
second device, e.g. a desktop computer, either via wires or
wirelessly. Synchronization ensures that the data on both devices
are identical (at least at the time of synchronization).
[0044] In wireless wide area networks, communication primarily
occurs through the transmission of radio signals over analog,
digital cellular, or personal communications service ("PCS")
networks. Signals may also be transmitted through microwaves and
other electromagnetic waves. At the present time, most wireless
data communication takes place across cellular systems using second
generation technology such as code-division multiple access
("CDMA"), time division multiple access ("TDMA"), the Global System
for Mobile Communications ("GSM"), Third Generation (wideband or
"3G"), Fourth Generation (broadband or "4G"), personal digital
cellular ("PDC"), or through packet-data technology over analog
systems such as cellular digital packet data ("CDPD") used on the
Advance Mobile Phone Service ("AMPS").
[0045] The terms "wireless application protocol" or "WAP" mean a
universal specification to facilitate the delivery and presentation
of web-based data on handheld and mobile devices with small user
interfaces. "Mobile Software" refers to the software operating
system, which allows for application programs to be implemented on
a mobile device such as a mobile telephone or PDA. Examples of
Mobile Software are Java and Java ME (Java and JavaME are
trademarks of Sun Microsystems, Inc. of Santa Clara, Calif.), BREW
(BREW is a registered trademark of Qualcomm Incorporated of San
Diego, Calif.), Windows Mobile (Windows is a registered trademark
of Microsoft Corporation of Redmond, Wash.), Palm OS (Palm is a
registered trademark of Palm, Inc. of Sunnyvale, Calif.), Symbian
OS (Symbian is a registered trademark of Symbian Software Limited
Corporation of London, United Kingdom), ANDROID OS (ANDROID is a
registered trademark of Google, Inc. of Mountain View, Calif.), and
iPhone OS (iPhone is a registered trademark of Apple, Inc. of
Cupertino, Calif.), and Windows Phone 7. "Mobile Apps" refers to
software programs written for execution with Mobile Software.
[0046] The terms "scan," "fiducial reference", "fiducial location",
"marker," "tracker" and "image information" have particular
meanings in the present disclosure. For purposes of the present
disclosure, "scan" or derivatives thereof refer to x-ray, magnetic
resonance imaging (MRI), computerized tomography (CT), sonography,
cone beam computerized tomography (CBCT), or any system that
produces a quantitative spatial representation of a patient. The
term "fiducial reference" or simply "fiducial" refers to an object
or reference on the image of a scan that is uniquely identifiable
as a fixed recognizable point. In the present specification the
term "fiducial location" refers to a useful location to which a
fiducial reference is attached. A "fiducial location" will
typically be proximate a surgical site. The term "marker" or
"tracking marker" refers to an object or reference that may be
perceived by a sensor proximate to the location of the surgical or
dental procedure, where the sensor may be an optical sensor, a
radio frequency identifier (RFID), a sonic motion detector, an
ultra-violet or infrared sensor. The term "tracker" refers to a
device or system of devices able to determine the location of the
markers and their orientation and movement continually in `real
time` during a procedure. As an example of a possible
implementation, if the markers are composed of printed targets then
the tracker may include a stereo camera pair. The term "image
information" is used in the present specification to describe
information obtained by the tracker, whether optical or otherwise,
and usable for determining the location of the markers and their
orientation and movement continually in `real time` during a
procedure.
[0047] FIG. 1 is a high-level block diagram of a computing
environment 100 according to one embodiment. FIG. 1 illustrates
server 110 and three clients 112 connected by network 114. Only
three clients 112 are shown in FIG. 1 in order to simplify and
clarify the description. Embodiments of the computing environment
100 may have thousands or millions of clients 112 connected to
network 114, for example the Internet. Users (not shown) may
operate software 116 on one of clients 112 to both send and receive
messages network 114 via server 110 and its associated
communications equipment and software (not shown).
[0048] FIG. 2 depicts a block diagram of computer system 210
suitable for implementing server 110 or client 112. Computer system
210 includes bus 212 which interconnects major subsystems of
computer system 210, such as central processor 214, system memory
217 (typically RAM, but which may also include ROM, flash RAM, or
the like), input/output controller 218, external audio device, such
as speaker system 220 via audio output interface 222, external
device, such as display screen 224 via display adapter 226, serial
ports 228 and 230, keyboard 232 (interfaced with keyboard
controller 233), storage interface 234, disk drive 237 operative to
receive floppy disk 238, host bus adapter (HBA) interface card 235A
operative to connect with Fibre Channel network 290, host bus
adapter (HBA) interface card 235B operative to connect to SCSI bus
239, and optical disk drive 240 operative to receive optical disk
242. Also included are mouse 246 (or other point-and-click device,
coupled to bus 212 via serial port 228), modem 247 (coupled to bus
212 via serial port 230), and network interface 248 (coupled
directly to bus 212).
[0049] Bus 212 allows data communication between central processor
214 and system memory 217, which may include read-only memory (ROM)
or flash memory (neither shown), and random access memory (RAM)
(not shown), as previously noted. RAM is generally the main memory
into which operating system and application programs are loaded.
ROM or flash memory may contain, among other software code, Basic
Input-Output system (BIOS), which controls basic hardware operation
such as interaction with peripheral components. Applications
resident with computer system 210 are generally stored on and
accessed via computer readable media, such as hard disk drives
(e.g., fixed disk 244), optical drives (e.g., optical drive 240),
floppy disk unit 237, or other storage medium. Additionally,
applications may be in the form of electronic signals modulated in
accordance with the application and data communication technology
when accessed via network modem 247 or interface 248 or other
telecommunications equipment (not shown).
[0050] Storage interface 234, as with other storage interfaces of
computer system 210, may connect to standard computer readable
media for storage and/or retrieval of information, such as fixed
disk drive 244. Fixed disk drive 244 may be part of computer system
210 or may be separate and accessed through other interface
systems. Modem 247 may provide direct connection to remote servers
via telephone link or the Internet via an Internet service provider
(ISP) (not shown). Network interface 248 may provide direct
connection to remote servers via direct network link to the
Internet via a POP (point of presence). Network interface 248 may
provide such connection using wireless techniques, including
digital cellular telephone connection, Cellular Digital Packet Data
(CDPD) connection, digital satellite data connection or the
like.
[0051] Many other devices or subsystems (not shown) may be
connected in a similar manner (e.g., document scanners, digital
cameras and so on), including the hardware components of FIGS.
3A-I, which alternatively may be in communication with associated
computational resources through local, wide-area, or wireless
networks or communications systems. Thus, while the disclosure may
generally discuss an embodiment where the hardware components are
directly connected to computing resources, one of ordinary skill in
this area recognizes that such hardware may be remotely connected
with computing resources. Conversely, all of the devices shown in
FIG. 2 need not be present to practice the present disclosure.
Devices and subsystems may be interconnected in different ways from
that shown in FIG. 2. Operation of a computer system such as that
shown in FIG. 2 is readily known in the art and is not discussed in
detail in this application. Software source and/or object codes to
implement the present disclosure may be stored in computer-readable
storage media such as one or more of system memory 217, fixed disk
244, optical disk 242, or floppy disk 238. The operating system
provided on computer system 210 may be a variety or version of
either MS-DOS.RTM. (MS-DOS is a registered trademark of Microsoft
Corporation of Redmond, Wash.), WINDOWS.RTM. (WINDOWS is a
registered trademark of Microsoft Corporation of Redmond, Wash.),
OS/2.RTM. (OS/2 is a registered trademark of International Business
Machines Corporation of Armonk, N.Y.), UNIX.RTM. (UNIX is a
registered trademark of X/Open Company Limited of Reading, United
Kingdom), Linux.RTM. (Linux is a registered trademark of Linus
Torvalds of Portland, Oreg.), or other known or developed operating
system.
[0052] Moreover, regarding the signals described herein, those
skilled in the art recognize that a signal may be directly
transmitted from a first block to a second block, or a signal may
be modified (e.g., amplified, attenuated, delayed, latched,
buffered, inverted, filtered, or otherwise modified) between
blocks. Although the signals of the above-described embodiments are
characterized as transmitted from one block to the next, other
embodiments of the present disclosure may include modified signals
in place of such directly transmitted signals as long as the
informational and/or functional aspect of the signal is transmitted
between blocks. To some extent, a signal input at a second block
may be conceptualized as a second signal derived from a first
signal output from a first block due to physical limitations of the
circuitry involved (e.g., there will inevitably be some attenuation
and delay). Therefore, as used herein, a second signal derived from
a first signal includes the first signal or any modifications to
the first signal, whether due to circuit limitations or due to
passage through other circuit elements which do not change the
informational and/or final functional aspect of the first
signal.
[0053] The present invention relates to a surgical hardware and
software monitoring system and method which allows for surgical
planning while the patient is available for surgery, for example
while the patient is being prepared for surgery so that the system
may model the surgical site. The system uses a particularly
configured piece of hardware, represented as fiducial key 10 in
FIG. 3A, to orient tracking marker 12 of the monitoring system with
regard to the critical area of the surgery. Fiducial key 10 is
attached to a location near the intended surgical area, in the
exemplary embodiment of the dental surgical area of FIG. 3A,
fiducial key 10 is attached to a dental splint 14. Tracking marker
12 may be connected to fiducial key 10 by tracking pole 11. In
embodiments in which the fiducial reference is directly visible to
a suitable tracker (see for example FIG. 5 and FIG. 6) that
acquires image information about the surgical site, a tracking
marker may be attached directly to the fiducial reference. For
example a dental surgery, the dental traking marker 14 may be used
to securely locate the fiducial 10 near the surgical area. The
fiducial key 10 may be used as a point of reference, or a fiducial,
for the further image processing of data acquired from tracking
marker 12 by the tracker.
[0054] In other embodiments additional tracking markers 12 may be
attached to items independent of the fiducial key 10 and any of its
associated tracking poles 11 or tracking markers 12. This allows
the independent items to be tracked by the tracker.
[0055] In a further embodiment at least one of the items or
instruments near the surgical site may optionally have a tracker
attached to function as tracker for the monitoring system of the
invention and to thereby sense the orientation and the position of
the tracking marker 12 and of any other additional tracking markers
relative to the scan data of the surgical area. By way of example,
the tracker attached to an instrument may be a miniature digital
camera and it may be attached, for example, to a dentist's drill.
Any other markers to be tracked by the tracker attached to the item
or instrument must be within the field of view of the tracker.
[0056] Using the dental surgery example, the patient is scanned to
obtain an initial scan of the surgical site. The particular
configuration of fiducial key 10 allows computer software stored in
memory and executed in a suitable controller, for example processor
214 and memory 217 of computer 210 of FIG. 2, to recognize its
relative position within the surgical site from the scan data, so
that further observations may be made with reference to both the
location and orientation of fiducial key 10. In some embodiments,
the fiducial reference includes a marking that is apparent as a
recognizable identifying symbol when scanned. In other embodiments,
the fiducial reference includes a shape that is distinct in the
sense that the body apparent on the scan has an asymmetrical form
allowing the front, rear, upper, and lower, and left/right defined
surfaces that may be unambiguously determined from the analysis of
the scan, thereby to allow the determination not only of the
location of the fiducial reference, but also of its
orientation.
[0057] In addition, the computer software may create a coordinate
system for organizing objects in the scan, such as teeth, jaw bone,
skin and gum tissue, other surgical instruments, etc. The
coordinate system relates the images on the scan to the space
around the fiducial and locates the instruments bearing markers
both by orientation and position. The model generated by the
monitoring system may then be used to check boundary conditions,
and in conjunction with the tracker display the arrangement in real
time on a suitable display, for example display 224 of FIG. 2.
[0058] In one embodiment, the computer system has a predetermined
knowledge of the physical configuration of fiducial key 10 and
examines slices/sections of the scan to locate fiducial key 10.
Locating of fiducial key 10 may be on its distinct shape, or on the
basis of distinctive identifying and orienting markings upon the
fiducial key or on attachments to the fiducial key 10 as tracking
marker 12. Fiducial key 10 may be rendered distinctly visible in
the scans through higher imaging contrast by the employ of
radio-opaque materials or high-density materials in the
construction of the fiducial key 10. In other embodiments the
material of the distinctive identifying and orienting markings may
be created using suitable high density or radio-opaque inks or
materials.
[0059] Once fiducial key 10 is identified, the location and
orientation of the fiducial key 10 is determined from the scan
segments, and a point within fiducial key 10 is assigned as the
center of the coordinate system. The point so chosen may be chosen
arbitrarily, or the choice may be based on some useful criterion. A
model is then derived in the form of a transformation matrix to
relate the fiducial system, being fiducial key 10 in one particular
embodiment, to the coordinate system of the surgical site. The
resulting virtual construct may be used by surgical procedure
planning software for virtual modeling of the contemplated
procedure, and may alternatively be used by instrumentation
software for the configuration of the instrument, for providing
imaging assistance for surgical software, and/or for plotting
trajectories for the conduct of the surgical procedure.
[0060] In some embodiments, the monitoring hardware includes a
tracking attachment to the fiducial reference. In the embodiment
pertaining to dental surgery the tracking attachment to fiducial
key 10 is tracking marker 12, which is attached to fiducial key 10
via tracking pole 11. Tracking marker 12 may have a particular
identifying pattern. The trackable attachment, for example tracking
marker 12, and even associated tracking pole 11 may have known
configurations so that observational data from tracking pole 11
and/or tracking marker 12 may be precisely mapped to the coordinate
system, and thus progress of the surgical procedure may be
monitored and recorded. For example, as particularly shown in FIG.
3J, fiducial key 10 may have hole 15 in a predetermined location
specially adapted for engagement with insert 17 of tracking pole
11. In such an arrangement, for example, tracking poles 11 may be
attached with a low force push into hole 15 of fiducial key 10, and
an audible haptic notification may thus be given upon successful
completion of the attachment.
[0061] It is further possible to reorient the tracking pole during
a surgical procedure. Such reorientation may be in order to change
the location of the procedure, for example where a dental surgery
deals with teeth on the opposite side of the mouth, where a surgeon
switches hands, and/or where a second surgeon performs a portion of
the procedure. For example, the movement of the tracking pole may
trigger a re-registration of the tracking pole with relation to the
coordinate system, so that the locations may be accordingly
adjusted. Such a re-registration may be automatically initiated
when, for example in the case of the dental surgery embodiment,
tracking pole 11 with its attached tracking marker 12 are removed
from hole 15 of fiducial key 10 and another tracking marker with
its associated tracking pole is connected to an alternative hole on
fiducial key 10. Additionally, boundary conditions may be
implemented in the software so that the user is notified when
observational data approaches and/or enters the boundary areas.
[0062] In a further embodiment of the system utilizing the
invention, a surgical instrument or implement, herein termed a
"hand piece" (see FIGS. 5 and 6), may also have a particular
configuration that may be located and tracked in the coordinate
system and may have suitable tracking markers as described herein.
A boundary condition may be set up to indicate a potential
collision with virtual material, so that when the hand piece is
sensed to approach the boundary condition an indication may appear
on a screen, or an alarm sound. Further, target boundary conditions
may be set up to indicate the desired surgical area, so that when
the trajectory of the hand piece is trending outside the target
area an indication may appear on screen or an alarm sound
indicating that the hand piece is deviating from its desired
path.
[0063] An alternative embodiment of some hardware components are
shown in FIGS. 3G-I. Fiducial key 10' has connection elements with
suitable connecting portions to allow a tracking pole 11' to
position a tracking marker 12' relative to the surgical site.
Conceptually, fiducial key 10' serves as an anchor for pole 11' and
tracking marker 12' in much the same way as the earlier embodiment,
although it has a distinct shape. The software of the monitoring
system is pre-programmed with the configuration of each
particularly identified fiducial key, tracking pole, and tracking
marker, so that the location calculations are only changed
according to the changed configuration parameters.
[0064] The materials of the hardware components may vary according
to regulatory requirements and practical considerations. Generally,
the key or fiducial component is made of generally radio opaque
material such that it does not produce noise for the scan, yet
creates recognizable contrast on the scanned image so that any
identifying pattern associated with it may be recognized. In
addition, because it is generally located on the patient, the
material should be lightweight and suitable for connection to an
apparatus on the patient. For example, in the dental surgery
example, the materials of the fiducial key must be suitable for
connection to a plastic splint and suitable for connection to a
tracking pole. In the surgical example the materials of the
fiducial key may be suitable for attachment to the skin or other
particular tissue of a patient.
[0065] The tracking markers are clearly identified by employing,
for example without limitation, high contrast pattern engraving.
The materials of the tracking markers are chosen to be capable of
resisting damage in autoclave processes and are compatible with
rigid, repeatable, and quick connection to a connector structure.
The tracking markers and associated tracking poles have the ability
to be accommodated at different locations for different surgery
locations, and, like the fiducial keys, they should also be
relatively lightweight as they will often be resting on or against
the patient. The tracking poles must similarly be compatible with
autoclave processes and have connectors of a form shared among
tracking poles.
[0066] The tracker employed in tracking the fiducial keys, tracking
poles and tracking markers should be capable of tracking with
suitable accuracy objects of a size of the order of 1.5 square
centimeters. The tracker may be, by way of example without
limitation, a stereo camera or stereo camera pair. While the
tracker is generally connected by wire to a computing device to
read the sensory input, it may optionally have wireless
connectivity to transmit the sensory data to a computing
device.
[0067] In embodiments that additionally employ a trackable piece of
instrumentation, such as a hand piece, tracking markers attached to
such a trackable piece of instrumentation may also be light-weight;
capable of operating in a 3 object array with 90 degrees
relationship; optionally having a high contrast pattern engraving
and a rigid, quick mounting mechanism to a standard hand piece.
[0068] In another aspect of the invention there is presented an
automatic registration method for tracking surgical activity, as
illustrated in FIGS. 4A-C. FIG. 4A and FIG. 4B together present,
without limitation, a flowchart of one method for determining the
three-dimensional location and orientation of the fiducial
reference from scan data. FIG. 4C presents a a flow chart of a
method for confirming the presence of a suitable tracking marker in
image information obtained by the tracker and determining the
three-dimensional location and orientation of the fiducial
reference based on the image information.
[0069] Once the process starts [402], as described in FIGS. 4A and
4B, the system obtains a scan data set [404] from, for example, a
CT scanner and checks for a default CT scan Hounsfield unit (HU)
value [at 406] for the fiducial which may or may not have been
provided with the scan based on a knowledge of the fiducial and the
particular scanner model, and if such a threshold value is not
present, then a generalized predetermined default value is employed
[408]. Next the data is processed by removing scan segments with
Hounsfield data values outside expected values associated with the
fiducial key values [at 410], following the collection of the
remaining points [at 412]. If the data is empty [at 414], the CT
value threshold is reduced [at 416], the original value restored
[at 418], and the segmenting processing scan segments continues [at
410]. Otherwise, with the existing data a center of mass is
calculated [at 420], along with calculating the X, Y, and Z axes
[at 422]. If the center of mass is not cross point of the XYZ axes
[at 424], then the user is notified [at 426] and the process
stopped [at 428]. If the center of mass is at the XYZ cross point
then the data points are compared with the designed fiducial data
[430]. If the cumulative error is larger than the maximum allowed
error [432] then the user is notified [at 434] and the process ends
[at 436]. If not, then the coordinate system is defined at the XYZ
cross point [at 438], the scan profile is updated for the HU units
[at 440].
[0070] Turning now to FIG. 4C, an image is obtained from the
tracker, being a suitable camera or other sensor [442]. The image
information is analyzed to determine whether a tracking marker is
present in the image information [444]. If not, then the user is
queried [446] as to whether the process should continue or not. If
not, then the process is ended [448]. If the process is to
continue, then the user can be notified that no tracking marker has
been found in the image information [450], and the process returns
to obtaining image information [442]. If a tracking marker has been
found based on the image information, or one has been attached by
the user upon the above notification [450], the offset and relative
orientation of the tracking marker to the fiducial reference is
obtained from a suitable database [452]. The term "database" is
used in this specification to describe any source, amount or
arrangement of such information, whether organized into a formal
multi-element or multi-dimensional database or not. A single data
set comprising offset value and relative orientation may suffice in
a simple implementation of this embodiment of the invention and may
be provided, for example, by the user or may be within a memory
unit of the controller or in a separate database or memory.
[0071] The offset and relative orientation of the tracking marker
is used to define the origin of a coordinate system at the fiducial
reference and to determine the three-dimensional orientation of the
fiducial reference based on the image information [454] and the
registration process ends [458]. In order to monitor the location
and orientation of the fiducial reference in real time, the process
may be looped back from step [454] to obtain new image information
from the camera [442]. A suitable query point may included to allow
the user to terminate the process. Detailed methods for determining
orientations and locations of predetermined shapes or marked
tracking markers from image data are known to practitioners of the
art and will not be dwelt upon here. The coordinate system so
derived is then used for tracking the motion of any items bearing
tracking markers in the proximity of the surgical site. Other
registration systems are also contemplated, for example using
current other sensory data rather than the predetermined offset, or
having a fiducial with a transmission capacity.
[0072] One example of an embodiment of the invention is shown in
FIG. 5. In addition to fiducial key 502 mounted at a predetermined
tooth and having a rigidly mounted tracking marker 504, an
additional instrument or implement 506, for example a hand piece
which may be a dental drill, may be observed by a camera 508
serving as tracker of the monitoring system.
[0073] Another example of an embodiment of the invention is shown
in FIG. 6. Surgery site 600, for example a human stomach or chest,
may have fiducial key 602 fixed to a predetermined position to
support tracking marker 604. Endoscope 606 may have further
tracking markers, and biopsy needle 608 may also be present bearing
a tracking marker at surgery site 600. Sensor 610, may be for
example a camera, infrared sensing device, or RADAR.
[0074] In another embodiment of the surgical monitoring system of
the present invention, shown schematically in FIG. 7A, the fiducial
key may comprise a multi-element fiducial pattern 710. In one
implementation the multi-element fiducial pattern 710 may be a
dissociable pattern. The term "dissociable pattern" is used in this
specification to describe a pattern comprising a plurality of
pattern segments 720 that topologically fit together to form a
contiguous whole pattern, and which may temporarily separated from
one another, either in whole or in part. The term "breakable
pattern" is used as an alternative term to describe such a
dissociable pattern. In other implementations of the invention the
segments of the multi-element fiducial pattern 710 do not form a
contiguous pattern, but instead their positions and orientations
with respect to one another are known when the multi-element
fiducial pattern 710 is applied on the body of the patient near a
critical area of a surgical site. Each pattern segment 720 is
individually locatable based on scan data of a surgical site to
which multi-element fiducial pattern 710 may be attached.
[0075] Pattern segments 720 are uniquely identifiable by a suitable
tracker 730, being differentiated from one another in one or more
of a variety of ways. Pattern segments 720 may be mutually
differentiable shapes that also allow the identification of their
orientations. Pattern segments 720 may be uniquely marked in one or
more of a variety of ways, including but not limited to barcoding
or orientation-defining symbols. The marking may be directly on the
pattern segments 720, or may be on tracking markers 740 attached to
pattern segments 720. The marking may be accomplished by a variety
of methods, including but not limited to engraving and printing. In
the embodiment shown in FIGS. 7A and 7B, by way of non-limiting
example, the letters F, G, J, L, P, Q and R have been used.
[0076] The materials of the multi-element fiducial pattern 710 and
pattern segments 720, and of any tracking markers 740 attached to
them, may vary according to regulatory requirements and practical
considerations. Generally, the key or fiducial component is made of
generally radio opaque material such that it does not produce noise
for the scan, yet creates recognizable contrast on the scanned
image so that any identifying pattern associated with it may be
recognized. The multi-element fiducial pattern 710 and pattern
segments 720 may have a distinct coloration difference from human
skin in order to be more clearly differentiable by tracker 730. In
addition, because it is generally located on the patient, the
material should be lightweight. The materials should also be
capable of resisting damage in autoclave processes.
[0077] A suitable tracker of any of the types already described is
used to locate and image multi-element fiducial pattern 710 within
the surgical area. Multi-element fiducial pattern 710 may be
rendered distinctly visible in scans of the surgical area through
higher imaging contrast by the employ of radio-opaque materials or
high-density materials in the construction of theti-element
fiducial pattern 710. In other embodiments the distinctive
identifying and orienting markings on the pattern segments 720 or
on the tracking markers 740 may be created using suitable
high-density materials or radio-opaque inks, thereby allowing the
orientations of pattern segments 720 to be determined based on scan
data.
[0078] During surgery the surgical area may undergo changes in
position and orientation. This may occur, for example, as a result
of the breathing or movement of the patient. In this process, as
shown in FIG. 7B, pattern segments 720 of multi-element fiducial
pattern 710 change their relative locations and also, in general,
their relative orientations. Information on these changes may be
used to gain information on the subcutaneous motion of the body of
the patient in the general vicinity of the surgical site by
relating the changed positions and orientations of pattern segments
720 to their locations and orientations in a scan done before
surgery.
[0079] Using abdominal surgery as example, the patient is scanned,
for example by an x-ray, magnetic resonance imaging (MRI),
computerized tomography (CT), or cone beam computerized tomography
(CBCT), to obtain an initial image of the surgical site. The
particular configuration of multi-element fiducial pattern 710
allows computer software to recognize its relative position within
the surgical site, so that further observations may be made with
reference to both the location and orientation of multi-element
fiducial pattern 710. In fact, the computer software may create a
coordinate system for organizing objects in the scan, such as skin,
organs, bones, and other tissue, other surgical instruments bearing
suitable tracking markers, and segments 720 of multi-element
fiducial pattern 710 etc.
[0080] In one embodiment, the computer system has a predetermined
knowledge of the configuration of multi-element fiducial pattern
710 and examines slices of a scan of the surgical site to locate
pattern segments 720 of multi-element fiducial pattern 710 based on
one or more of the radio-opacity density of the material of the
pattern segments 720, their shapes and their unique tracking
markers 740. Once the locations and orientations of the pattern
segments 720 have been determined, a point within or near
multi-element fiducial pattern 710 is assigned as the center of the
coordinate system. The point so chosen may be chosen arbitrarily,
or the choice may be based on some useful criterion. A
transformation matrix is derived to relate multi-element fiducial
pattern 710 to the coordinate system of the surgical site. The
resulting virtual construct may then be used by surgical procedure
planning software for virtual modeling of the contemplated
procedure, and may alternatively be used by instrumentation
software for the configuration of the instrument, for providing
imaging assistance for surgical software, and/or for plotting
trajectories for the conduct of the surgical procedure.
[0081] Multi-element fiducial pattern 710 changes its shape as the
body moves during surgery. The relative locations and relative
orientations of pattern segments 720 change in the process. (see
FIG. 7A relative to FIG. 7B.) In this process the integrity of
individual pattern segments 720 is maintained and they may be
tracked by tracker 730, including but not limited to a stereo video
camera. The changed multi-element fiducial pattern 710' may be
compared with initial multi-element fiducial pattern 710' to create
a transformation matrix. The relocating and reorienting of pattern
segments 720 may therefore be mapped on a continuous basis within
the coordinate system of the surgical site. In FIGS. 7A and 7B a
total of seven pattern segments 720 are shown. In other embodiments
multi-element fiducial pattern 710 may comprise larger or smaller
numbers of pattern segments 720. During operation of the surgical
monitoring system of this embodiment of the present invention a
selection of pattern segments 720 may be employed and there is no
limitation that all pattern segments 720 of multi-element fiducial
pattern 710 have to be employed. The decision as to how many
pattern segments 720 to employ may, by way of example, be based on
the resolution required for the surgery to be done or on the
processing speed of the controller, which may be, for example,
computer 210 of FIG. 2.
[0082] For the sake of clarity, FIG. 7A employs a dissociable
multi-element fiducial pattern. In other embodiments the
multi-element fiducial pattern may have a dissociated fiducial
pattern, such as that of FIG. 7B, as default. The individual
pattern segments 720 then change position as the body of the
patient changes shape near the surgical site during the surgery. In
yet other embodiments tracking markers 740 may be absent and the
tracking system may rely on tracking the pattern segments 720
purely on the basis of their unique shapes, which lend themselves
to determining orientation due to a lack of a center of symmetry.
As already pointed out, in other embodiments the pattern segments
720 are not in general limited to being capable of being joined
topologically at their perimeters to form a contiguous surface. Nor
is there a particular limitation on the general shape of the
multi-element fiducial pattern.
[0083] In another aspect of the invention there is presented an
automatic registration method for tracking surgical activity using
a multi-element fiducial pattern 710, as shown in the flow chart
diagram of FIG. 8A, FIG. 8B and FIG. 8C. FIG. 8A and FIG. 8B
together present, without limitation, a flowchart of one method for
determining the three-dimensional location and orientation of one
segment of multi-element fiducial pattern 710 from scan data. FIG.
8C presents a a flow chart of a method for determining the spatial
distortion of the surgical site based on the changed orientations
and locations of pattern segments 720 of multi-element fiducial
pattern 710, using as input the result of applying the method shown
in FIG. 8A and FIG. 8B to every one of the pan segments 720 that is
to be employed in the determg the spatial distortion of the
surgical site. In principle, not all pattern segments 720 need to
be employed.
[0084] Once the process starts [802], as described in FIGS. 8A and
8B, the system obtains a scan data set [404] from, for example, a
CT scanner and checks for a default CT scan Hounsfield unit (HU)
value [806] for the fiducial, which may or may not have been
provided with the scan based on a knowledge of the fiducial and the
particular scanner model. If such a default value is not present,
then a generalized predetermined system default value is employed
[808]. Next the data is processed by removing scan slices or
segments with Hounsfield data values outside the expected values
associated with the fiducial key [810], followed by the collecting
of the remaining points [812]. If the data is empty [814], the CT
value threshold is adjusted [816], the original data restored
[818], and the processing of scan slices continues [810].
Otherwise, with the existing data a center of mass is calculated
[820], as are the X, Y and Z axes [822]. If the center of mass is
not at the X, Y, Z cross point [824], then the user is notified
[826] and the process ended [828]. If the center of mass is at the
X, Y, Z cross point [824], then the pattern of the fiducial is
compared to the data [836], and if the cumulative error is larger
than the maximum allowed error [838] the user is notified [840] and
the process is ended [842]. If the cumulative error is not larger
than the maximum allowed error [838], then the coordinate system is
defined at the XYZ cross-point [844] and the CT profile is updated
for HU units [846]. This process of FIG. 8A and FIG. 8B is repeated
for every one of the pattern segments 720 that is to be employed in
determining the spatial distortion of the surgical site. The
information on the location and orientation of every one of pattern
segments 720 is then used as input to the method described at the
hand of FIG. 8C.
[0085] Turning now to FIG. 8C, image information is obtained from
the camera [848] and it is determined whether a particular segment
720 of the multi-element fiducial pattern 710 on the patient body
is present in the image information [850]. If the particular
segment 720 is not present in the image information, then the user
is queried as to whether the process should continue [852]. If not,
then the process is ended [854]. If the process is to continue, the
user is notified that the particular segment 720 was not found in
the image information [856] and the process returns to obtaining
image information from the camera [848]. If the particular segment
720 is present in the image information at step [850], then, every
other pattern segment 720 employed is identified and the
three-dimensional location and orientation of all segments 720
employed are determined based on the image information [858]. The
three-dimensional location and orientation of every pattern segment
employed based on the image information is compared with the three
dimensional location and orientation of the same pattern segment as
based on the scan data [860]. Based on this comparison the spatial
distortion of the surgical site is determined [862]. In order to
monitor such distortions in real time, the process may be looped
back to obtain image information from the camera [848]. A suitable
query point [864] may be included to allow the user to terminate
the process [866]. Detailed methods for determining orientations
and locations of predetermined shapes or marked tracking markers
from image data are known to practitioners of the art and will not
be dwelt upon here.
[0086] By the above method the software of the controller, for
example computer 210 of FIG. 2, is capable of recognizing
multi-element fiducial pattern 710 and calculating a model of the
surgical site based on the identity of multi-element fiducial
pattern 710 and its changes in shape based on the observation data
received from multi-element fiducial pattern 710. This allows the
calculation in real time of the locations and orientations of
anatomical features in the proximity of the multi-element fiducial
pattern 710.
[0087] While this invention has been described as having an
exemplary design, the present invention may be further modified
within the spirit and scope of this disclosure. This application is
therefore intended to cover any variations, uses, or adaptations of
the invention using its general principles. Further, this
application is intended to cover such departures from the present
disclosure as come within known or customary practice in the art to
which this invention pertains.
* * * * *