U.S. patent application number 11/796220 was filed with the patent office on 2008-02-21 for steerable segmented endoscope and method of insertion.
Invention is credited to Amir Belson.
Application Number | 20080045794 11/796220 |
Document ID | / |
Family ID | 25516188 |
Filed Date | 2008-02-21 |
United States Patent
Application |
20080045794 |
Kind Code |
A1 |
Belson; Amir |
February 21, 2008 |
Steerable segmented endoscope and method of insertion
Abstract
A steerable endoscope has an elongated body with a selectively
steerable distal portion and an automatically controlled proximal
portion. The endoscope body is inserted into a patient and the
selectively steerable distal portion is used to select a desired
path within the patient's body. When the endoscope body is
advanced, an electronic motion controller operates the
automatically controlled proximal portion to assume the selected
curve of the selectively steerable distal portion. Another desired
path is selected with the selectively steerable distal portion and
the endoscope body is advanced again. As the endoscope body is
further advanced, the selected curves propagate proximally along
the endoscope body, and when the endoscope body is withdrawn
proximally, the selected curves propagate distally along the
endoscope body. This creates a serpentine motion in the endoscope
body allowing it to negotiate tortuous curves along a desired path
through or around and between organs within the body.
Inventors: |
Belson; Amir; (Cupertino,
CA) |
Correspondence
Address: |
SHAYGLENN LLP
2755 CAMPUS DRIVE
SUITE 210
SAN MATEO
CA
94403
US
|
Family ID: |
25516188 |
Appl. No.: |
11/796220 |
Filed: |
April 27, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10622801 |
Jul 18, 2003 |
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11796220 |
Apr 27, 2007 |
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09969927 |
Oct 2, 2001 |
6610007 |
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10622801 |
Jul 18, 2003 |
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09790204 |
Feb 20, 2001 |
6468203 |
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09969927 |
Oct 2, 2001 |
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60194140 |
Apr 3, 2000 |
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Current U.S.
Class: |
600/145 ;
600/117; 600/146 |
Current CPC
Class: |
A61B 1/0016 20130101;
A61B 1/31 20130101; A61B 5/065 20130101; A61B 2034/301 20160201;
A61B 1/015 20130101; A61B 1/00004 20130101; A61B 1/05 20130101;
A61B 1/00055 20130101; A61B 1/0053 20130101; A61B 1/008 20130101;
A61B 2034/741 20160201; A61B 2034/742 20160201; A61B 1/018
20130101; A61B 1/0055 20130101 |
Class at
Publication: |
600/145 ;
600/117; 600/146 |
International
Class: |
A61B 1/00 20060101
A61B001/00 |
Claims
1. A system for determining the shape of an instrument during or
after insertion of the instrument into a body cavity, comprising:
an instrument having an elongate body comprising a selectively
steerable distal tip, and a plurality of automatically controlled
segments proximal to said selectively steerable distal tip; a
segment controller associated with each of said plurality of
automatically controlled segments, wherein each segment controller
provides angular position data for the segment with which it is
associated; a controller in communication with each segment
controller using a communication channel; and an axial motion
transducer that provides axial position data of said elongate body
to said controller; wherein said controller generates a three
dimensional model of the shape of said instrument within said body
cavity.
2. The system according to claim 1, wherein said controller
commands each segment controller to control the geometry of the
segment with which it is associated.
3. The system according to claim 1 further comprising: a display
for displaying said three dimensional model.
4. The system according to claim 1, wherein said communication
channel comprises an electrically conductive material.
5. The system according to claim 1, wherein said communication
channel is an optical fiber.
6. The system according to claim 1, wherein said communication
channel comprises wireless transmission.
7. The system according to claim 1 further comprising: an actuator
within each segment adapted to modify the shape of the segment.
8. The system according to claim 7, wherein the actuator is a
plastic actuator.
9. The system according to claim 1, wherein an image of said three
dimensional model of the shape of said instrument is combined with
a three dimensional image of said body cavity to form a combined
three dimensional image, thereby facilitating guidance of said
instrument within said body cavity.
10. The system according to claim 1, wherein said three dimensional
model of the shape of said instrument approximately defines a three
dimensional shape of said body cavity.
11. The system according to claim 7, wherein the combined three
dimensional image shows corresponding movement of said instrument
within said body cavity.
12. A method for determining the three dimensional shape of an
instrument during or after insertion of said instrument into a body
cavity, wherein said instrument comprises an elongate body
comprising a selectively steerable distal tip, and a plurality of
automatically controlled segments proximal to said selectively
steerable distal tip, said method comprising the steps of:
advancing said instrument into said body cavity; providing axial
position data to a controller, wherein said axial position data is
relative to a datum; providing angular position data to said
controller from a segment controller associated with each of said
plurality of automatically controlled segments; and generating in
electronic memory of said controller a three-dimensional shape of
said instrument using the provided axial position data and the
angular position data.
13. The method for determining the three dimensional shape of an
instrument according to claim 12, wherein the step of providing
angular position data further comprises: providing angular position
data to said controller from each segment controller using an
optical fiber communications channel between said controller and
each segment controller.
14. The method for determining the three dimensional shape of an
instrument according to claim 12, wherein the step of providing
angular position data further comprises: providing angular position
data to said controller from each segment controller using an
electrically conductive communication channel between said
controller and each segment controller.
15. The method for determining the three dimensional shape of an
instrument according to claim 12, wherein the step of providing
angular position data further comprises: wirelessly providing
angular position data to said controller from each segment.
Description
CROSS-REFERENCE TO OTHER APPLICATIONS
[0001] The present application is a continuation of U.S. patent
application Ser. No. 09/969,927 entitled "Steerable Segmented
Endoscope and Method of Insertion" filed Oct. 2, 2001, which is a
continuation-in-part of U.S. patent application Ser. No. 09/790,204
entitled "Steerable Endoscope and Improved Method of Insertion"
filed Feb. 20, 2001, which claims priority of U.S. Provisional
Patent Application No. 60/194,140 filed Apr. 3, 2000, each of which
is incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates generally to endoscopes and
endoscopic medical procedures. More particularly, it relates to a
method and apparatus to facilitate insertion of a flexible
endoscope along a tortuous path, such as for colonoscopic
examination and treatment.
BACKGROUND OF THE INVENTION
[0003] An endoscope is a medical instrument for visualizing the
interior of a patient's body. Endoscopes can be used for a variety
of different diagnostic and interventional procedures, including
colonoscopy, bronchoscopy, thoracoscopy, laparoscopy and video
endoscopy.
[0004] Colonoscopy is a medical procedure in which a flexible
endoscope, or colonoscope, is inserted into a patient's colon for
diagnostic examination and/or surgical treatment of the colon. A
standard colonoscope is typically 135-185 cm in length and 12-19 mm
in diameter, and includes a fiberoptic imaging bundle or a
miniature camera located at the instrument's tip, illumination
fibers, one or two instrument channels that may also be used for
insufflation or irrigation, air and water channels, and vacuum
channels. The colonoscope is inserted via the patient's anus and is
advanced through the colon, allowing direct visual examination of
the colon, the ileocecal valve and portions of the terminal ileum.
Insertion of the colonoscope is complicated by the fact that the
colon represents a tortuous and convoluted path. Considerable
manipulation of the colonoscope is often necessary to advance the
colonoscope through the colon, making the procedure more difficult
and time consuming and adding to the potential for complications,
such as intestinal perforation. Steerable colonoscopes have been
devised to facilitate selection of the correct path though the
curves of the colon. However, as the colonoscope is inserted
farther and farther into the colon, it becomes more difficult to
advance the colonoscope along the selected path. At each turn, the
wall of the colon must maintain the curve in the colonoscope. The
colonoscope rubs against the mucosal surface of the colon along the
outside of each turn. Friction and slack in the colonoscope build
up at each turn, making it more and more difficult to advance and
withdraw the colonoscope. In addition, the force against the wall
of the colon increases with the buildup of friction. In cases of
extreme tortuosity, it may become impossible to advance the
colonoscope all of the way through the colon.
[0005] Steerable endoscopes, catheters and insertion devices for
medical examination or treatment of internal body structures are
described in the following U.S. patents, the disclosures of which
are hereby incorporated by reference in their entirety: U.S. Pat.
Nos. 4,753,223; 5,337,732; 5,662,587; 4,543,090; 5,383,852;
5,487,757 and 5,337,733.
SUMMARY OF THE INVENTION
[0006] In keeping with the foregoing discussion, the present
invention takes the form of a steerable endoscope for negotiating
tortuous paths through a patient's body. The steerable endoscope
can be used for a variety of different diagnostic and
interventional procedures, including colonoscopy, upper endoscopy,
bronchoscopy, thoracoscopy, laparoscopy and video endoscopy. The
steerable endoscope is particularly well suited for negotiating the
tortuous curves encountered when performing a colonoscopy
procedure.
[0007] The steerable endoscope has an elongated body with a
manually or selectively steerable distal portion and an
automatically controlled proximal portion. The selectively
steerable distal portion can be selectively steered or bent up to a
full 180 degree bend in any direction. A fiberoptic imaging bundle
and one or more illumination fibers extend through the body from
the proximal end to the distal end. Alternatively, the endoscope
can be configured as a video endoscope with a miniaturized video
camera, such as a CCD camera, which transmits images to a video
monitor by a transmission cable or by wireless transmission, or
alternatively through the use of CMOS imaging technology.
Optionally, the endoscope may include one or two instrument
channels that may also be used for insufflation or irrigation, air
and water channels, and vacuum channels.
[0008] A proximal handle attached to the elongate body includes an
ocular for direct viewing and/or for connection to a video camera,
a connection to an illumination source and one or more luer lock
fittings that are connected to the instrument channels. The handle
is connected to a steering control for selectively steering or
bending the selectively steerable distal portion in the desired
direction and to an electronic motion controller for controlling
the automatically controlled proximal portion of the endoscope. An
axial motion transducer is provided to measure the axial motion of
the endoscope body as it is advanced and withdrawn. Optionally, the
endoscope may include a motor or linear actuator for both
automatically advancing and withdrawing the endoscope, or for
automatically advancing and passively withdrawing the
endoscope.
[0009] One preferable embodiment of the endoscope includes a
segmented endoscopic embodiment having multiple independently
controllable segments which may be individually motorized and
interconnected by joints. Each of the individual adjacent segments
may be pivotable about two independent axes to offer a range of
motion during endoscope insertion into a patient.
[0010] This particular embodiment, as mentioned, may have
individual motors, e.g., small brushed DC motors, to actuate each
individual segment. Furthermore, each segment preferably has a
backbone segment which defines a lumen therethrough to allow a
continuous lumen to pass through the entire endoscopic instrument
to provide an access channel through which wires, optical fibers,
air and/or water channels, various endoscopic tools, or any variety
of devices and wires may be routed. The entire assembly, i.e.,
motors, backbone, cables, etc., may be encased or covered in a
biocompatible material, e.g., a polymer, which is also preferably
lubricious to allow for minimal frictional resistance during
endoscope insertion and advancement into a patient. This
biocompatible cover may be removable from the endoscopic body to
expose the motors and backbone assembly to allow for direct access
to the components. This may also allow for the cover to be easily
replaced and disposed after use in a patient.
[0011] The method of the present invention involves inserting the
distal end of the endoscope body into a patient, either through a
natural orifice or through an incision, and steering the
selectively steerable distal portion to select a desired path. When
the endoscope body is advanced or inserted further into the
patient's body, the electronic motion controller operates the
automatically controlled proximal portion of the body to assume the
selected curve of the selectively steerable distal portion. This
process is repeated by selecting another desired path with the
selectively steerable distal portion and advancing the endoscope
body again. As the endoscope body is further advanced, the selected
curves propagate proximally along the endoscope body. Similarly,
when the endoscope body is withdrawn proximally, the selected
curves propagate distally along the endoscope body, either
automatically or passively. This creates a sort of serpentine
motion in the endoscope body that allows it to negotiate tortuous
curves along a desired path through or around and between organs
within the body.
[0012] The method can be used for performing colonoscopy or other
endoscopic procedures, such as bronchoscopy, thoracoscopy,
laparoscopy and video endoscopy. In addition, the apparatus and
methods of the present invention can be used for inserting other
types of instruments, such as surgical instruments, catheters or
introducers, along a desired path within the body.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 shows a prior art colonoscope being employed for a
colonoscopic examination of a patient's colon.
[0014] FIG. 2 shows a first embodiment of the steerable endoscope
of the present invention.
[0015] FIG. 3 shows a second embodiment of the steerable endoscope
of the present invention.
[0016] FIG. 4 shows a third embodiment of the steerable endoscope
of the present invention.
[0017] FIG. 5 shows a fourth embodiment of the steerable endoscope
of the present invention.
[0018] FIG. 6 shows a wire frame model of a section of the body of
the endoscope in a neutral or straight position.
[0019] FIG. 7 shows the wire frame model of the endoscope body
shown in FIG. 6 passing through a curve in a patient's colon.
[0020] FIG. 8 shows a representative portion of an alternative
endoscopic body embodiment having multiple segments interconnected
by joints.
[0021] FIG. 9 shows a partial schematic representation of the
embodiment of FIG. 8 showing two segments being pivotable about two
independent axes.
[0022] FIG. 10 shows a preferable endoscope embodiment having
motorized segmented joints.
[0023] FIGS. 11A-11B show exploded isometric assembly views of two
adjacent segments and an individual segment, respectively, from the
embodiment shown in FIG. 10.
[0024] FIGS. 12-17 show the endoscope of the present invention
being employed for a colonoscopic examination of a patient's
colon.
[0025] FIGS. 18-20 show an endoscope being advanced through a
patient's colon while a datum measures the distance advanced into
the patient.
[0026] FIG. 21 shows a schematic representation of one embodiment
of a control system which may be used to control and command the
individual segments of a segmented endoscopic device of the type
shown in FIGS. 8-11B.
[0027] FIG. 22 shows a flow chart embodiment for the master
controller algorithm which may be used to control the overall
function during endoscope insertion into a patient.
[0028] FIG. 23 shows a flowchart embodiment of the segment
controller algorithm.
[0029] FIGS. 24-26 shows a non-contact method of measurement and
tracking of an endoscope using an external navigational system such
as a global positioning system.
DETAILED DESCRIPTION OF THE INVENTION
[0030] FIG. 1 shows a prior art colonoscope 500 being employed for
a colonoscopic examination of a patient's colon C. The colonoscope
500 has a proximal handle 506 and an elongate body 502 with a
steerable distal portion 504. The body 502 of the colonoscope 500
has been lubricated and inserted into the colon C via the patient's
anus A. Utilizing the steerable distal portion 504 for guidance,
the body 502 of the colonoscope 500 has been maneuvered through
several turns in the patient's colon C to the ascending colon G.
Typically, this involves a considerable amount of manipulation by
pushing, pulling and rotating the colonoscope 500 from the proximal
end to advance it through the turns of the colon C. After the
steerable distal portion 504 has passed, the wall of the colon C
maintains the curve in the flexible body 502 of the colonoscope 500
as it is advanced. Friction develops along the body 502 of the
colonoscope 500 as it is inserted, particularly at each turn in the
colon C. Because of the friction, when the user attempts to advance
the colonoscope 500, the body 502' tends to move outward at each
curve, pushing against the wall of the colon C, which exacerbates
in the problem by increasing the friction and making it more
difficult to advance the colonoscope 500. On the other hand, when
the colonoscope 500 is withdrawn, the body 502'' tends to move
inward at each curve taking up the slack that developed when the
colonoscope 500 was advanced. When the patient's colon C is
extremely tortuous, the distal end of the body 502 becomes
unresponsive to the user's manipulations, and eventually it may
become impossible to advance the colonoscope 500 any farther. In
addition to the difficulty that it presents to the user, tortuosity
of the patient's colon also increases the risk of complications,
such as intestinal perforation.
[0031] FIG. 2 shows a first embodiment of the steerable endoscope
100 of the present invention. The endoscope 100 has an elongate
body 102 with a manually or selectively steerable distal portion
104 and an automatically controlled proximal portion 106. The
selectively steerable distal portion 104 can be selectively steered
or bent up to a full 180 degree bend in any direction. A fiberoptic
imaging bundle 112 and one or more illumination fibers 114 extend
through the body 102 from the proximal end 110 to the distal end
108. Alternatively, the endoscope 100 can be configured as a video
endoscope with a miniaturized video camera, such as a CCD camera,
positioned at the distal end 108 of the endoscope body 102. The
images from the video camera can be transmitted to a video monitor
by a transmission cable or by wireless transmission where images
may be viewed in real-time or recorded by a recording device onto
analog recording medium, e.g., magnetic tape, or digital recording
medium, e.g., compact disc, digital tape, etc. Optionally, the body
102 of the endoscope 100 may include one or two instrument channels
116, 118 that may also be used for insufflation or irrigation, air
and water channels, and vacuum channels. The body 102 of the
endoscope 100 is highly flexible so that it is able to bend around
small diameter curves without buckling or kinking while maintaining
the various channels intact. When configured for use as a
colonoscope, the body 102 of the endoscope 100 is typically from
135 to 185 cm in length and approximately 12-13 mm in diameter. The
endoscope 100 can be made in a variety of other sizes and
configurations for other medical and industrial applications.
[0032] A proximal handle 120 is attached to the proximal end 110 of
the elongate body 102. The handle 120 includes an ocular 124
connected to the fiberoptic imaging bundle 112 for direct viewing
and/or for connection to a video camera 126 or a recording device
127. The handle 120 is connected to an illumination source 128 by
an illumination cable 134 that is connected to or continuous with
the illumination fibers 114. A first luer lock fitting, 130 and a
second luer lock fitting 132 on the handle 120 are connected to the
instrument channels 116, 118.
[0033] The handle 120 is connected to an electronic motion
controller 140 by way of a controller cable 136. A steering control
122 is connected to the electronic motion controller 140 by way of
a second cable 13 M. The steering control 122 allows the user to
selectively steer or bend the selectively steerable distal portion
104 of the body 102 in the desired direction. The steering control
122 may be a joystick controller as shown, or other known steering
control mechanism. The electronic motion controller 140 controls
the motion of the automatically controlled proximal portion 106 of
the body 102. The electronic motion controller 140 may be
implemented using a motion control program running on a
microcomputer or using an application-specific motion controller.
Alternatively, the electronic motion controller 140 may be
implemented using, a neural network controller.
[0034] An axial motion transducer 150 is provided to measure the
axial motion of the endoscope body 102 as it is advanced and
withdrawn. The axial motion transducer 150 can be made in many
possible configurations. By way of example, the axial motion
transducer 150 in FIG. 2 is configured as a ring 152 that surrounds
the body 102 of the endoscope 100. The axial motion transducer 150
is attached to a fixed point of reference, such as the surgical
table or the insertion point for the endoscope 100 on the patient's
body. As the body 102 of the endoscope 100 slides through the axial
motion transducer 150, it produces a signal indicative of the axial
position of the endoscope body 102 with respect to the fixed point
of reference and sends a signal to the electronic motion controller
140 by telemetry or by a cable (not shown). The axial motion
transducer 150 may use optical, electronic or mechanical means to
measure the axial position of the endoscope body 102. Other
possible configurations for the axial motion transducer 150 are
described below.
[0035] FIG. 3 shows a second embodiment of the endoscope 100 of the
present invention. As in the embodiment of FIG. 2, the endoscope
100 has an elongate body 102 with a selectively steerable distal
portion 104 and an automatically controlled proximal portion 106.
The steering control 122 is integrated into proximal handle 120 in
the form or one or two dials for selectively steering, the
selectively steerable distal portion 104 of the endoscope 100.
Optionally, the electronic motion controller 140 may be
miniaturized and integrated into proximal handle 120, as well. In
this embodiment, the axial motion transducer 150 is configured with
a base 154 that is attachable to a fixed point of reference, such
as the surgical table. A first roller 156 and a second roller 158
contact the exterior of the endoscope body 102. A multi-turn
potentiometer 160 or other motion transducer is connected to the
first roller 156 to measure the axial motion of the endoscope body
102 and to produce a signal indicative of the axial position.
[0036] The endoscope 100 may be manually advanced or withdrawn by
the user by grasping the body 102 distal to the axial motion
transducer 150. Alternatively, the first roller 156 and/or second
roller 158 may be connected to at least one motor, e.g., motor 162,
for automatically advancing and withdrawing the body 102 of the
endoscope 100.
[0037] FIG. 4 shows a third embodiment of the endoscope 100 of the
present invention, which utilizes an elongated housing 170 to
organize and contain the endoscope 100. The housing 170 has a base
172 with a linear track 174 to guide the body 102 of the endoscope
100. The housing 170 may have an axial motion transducer 150' that
is configured as a linear motion transducer integrated into the
linear track 174. Alternatively, the housing, 170 may have an axial
motion transducer 150'' configured similarly to the axial motion
transducer 150 in FIG. 2 or 3. The endoscope 100 may be manually
advanced or withdrawn by the user by grasping the body 102 distal
to the housing 170. Alternatively, the housing 170 may include a
motor 176 or other linear motion actuator for automatically
advancing and withdrawing the body 102 of the endoscope 100. In
another alternative configuration, a motor with friction wheels,
similar to that described above in connection with FIG. 3, may be
integrated into the axial motion transducer 150''.
[0038] FIG. 5 shows a fourth embodiment of the endoscope 100 of the
present invention, which utilizes a rotary housing 180 to organize
and contain the endoscope 100. The housing 180 has a base 182 with
a rotating drum 184 to guide the body 102 of the endoscope 100. The
housing 180 may have an axial motion transducer 150''' that is
configured as a potentiometer connected to the pivot axis 186 of
the rotating drum 184. Alternatively, the housing 180 may have an
axial motion transducer 150'' configured similarly to the axial
motion transducer 150 in FIG. 2 or 3. The endoscope 100 may be
manually advanced or withdrawn by the user by grasping the body 102
distal to the housing 180. Alternatively, the housing 180 may
include a motor 188 connected to the rotating drum 184 for
automatically advancing and withdrawing the body 102 of the
endoscope 100. In another alternative configuration, a motor with
friction wheels, similar to that described above in connection with
FIG. 3, may be integrated into the axial motion transducer
150''.
[0039] FIG. 6 shows a wire frame model of a section of the body 102
of the endoscope 100 in a neutral or straight position. Most of the
internal structure of the endoscope body 102 has been eliminated in
this drawing for the sake of clarity. The endoscope body 102 is
divided up into sections 1, 2, 3 . . . 10, etc. The geometry of
each section is defined by four length measurements along the a, b,
c and d axes. For example, the geometry of section 1 is defined by
the four length measurements l.sub.1a, l.sub.1b, l.sub.1c,
l.sub.1d, and the geometry of section 2 is defined by the four
length measurements l.sub.2a, l.sub.2b, l.sub.2c, l.sub.2d, etc.
Preferably, each of the length measurements is individually
controlled by a linear actuator (not shown). The linear actuators
may utilize one of several different operating principles. For
example, each of the linear actuators may be a self-heating NiTi
alloy linear actuator or an electrorheological plastic actuator, or
other known mechanical, pneumatic, hydraulic or electromechanical
actuator. The geometry of each section may be altered using the
linear actuators to change the four length measurements along the
a, b, c and d axes. Preferably, the length measurements are changed
in complementary pairs to selectively bend the endoscope body 102
in a desired direction. For example, to bend the endoscope body 102
in the direction of the a axis, the measurements l.sub.1a,
l.sub.2a, l.sub.3a . . . l.sub.10a would be shortened and the
measurements l.sub.1b, l.sub.2b, l.sub.3b . . . l.sub.10b would be
lengthened an equal amount. The amount by which these measurements
are changed determines the radius of the resultant curve.
[0040] In the selectively steerable distal portion 104 of the
endoscope body 102, the linear actuators that control the a, b, c
and d axis measurements of each section are selectively controlled
by the user through the steering control 122. Thus, by appropriate
control of the a, b, c and d axis measurements, the selectively
steerable distal portion 104 of the endoscope body 102 can be
selectively steered or bent up to a full 180 degrees in any
direction.
[0041] In the automatically controlled proximal portion 106,
however, the a, b, c and d direction measurements of each section
are automatically controlled by the electronic motion controller
140, which uses a curve propagation method to control the shape of
the endoscope body 102. To explain how the curve propagation method
operates, FIG. 7 shows the wire frame model of a part of the
automatically controlled proximal portion 106 of the endoscope body
102 shown in FIG. 6 passing, through a curve in a patient's colon
C. For simplicity, an example of a two-dimensional curve is shown
and only the a and b axes will be considered. In a
three-dimensional curve all four of the a, b, c and d axes would be
brought into play.
[0042] In FIG. 7, the endoscope body 102 has been maneuvered
through the curve in the colon C with the benefit of the
selectively steerable distal portion 104 (this part of the
procedure is explained in more detail below) and now the
automatically controlled proximal portion 106 resides in the curve.
Sections 1 and 2 are in a relatively straight part of the colon C,
therefore l.sub.1a=l.sub.1b and l.sub.2a=l.sub.2b. However, because
sections 3-7 are in the S-shaped curved section,
l.sub.3a<l.sub.3b, l.sub.4a<l.sub.4b and
l.sub.5a<l.sub.5b, but l.sub.6a>l.sub.6b,
l.sub.7a>l.sub.7b and l.sub.8a>l.sub.8b. When the endoscope
body 102 is advanced distally by one unit, section 1 moves into the
position marked 1', section 2 moves into the position previously
occupied by section 1, section 3 moves into the position previously
occupied by section 2, etc. The axial motion transducer 150
produces a signal indicative of the axial position of the endoscope
body 102 with respect to a fixed point of reference and sends the
signal to the electronic motion controller 140, under control of
the electronic motion controller 140, each time the endoscope body
102 advances one unit, each section in the automatically controlled
proximal portion 106 is signaled to assume the shape of the section
that previously occupied the space that it is now in. Therefore,
when the endoscope body 102 is advanced to the position marked 1',
l.sub.1a=l.sub.1b, l.sub.2a=l.sub.2b, l.sub.3a=l.sub.3b,
l.sub.4a<l.sub.4b, l.sub.5a<l.sub.5b, l.sub.6a<l.sub.6b,
l.sub.7a>l.sub.7b and l.sub.8a>l.sub.8b, and
l.sub.9a>l.sub.9b, when the endoscope body 102 is advanced to
the position marked 1'', l.sub.1a=l.sub.1b, l.sub.2a=l.sub.2,
l.sub.3a=l.sub.3b, l.sub.4a=l.sub.4b, l.sub.5a<l.sub.5b,
l.sub.6a<l.sub.6b, l.sub.7a<l.sub.7b, l.sub.8a>l.sub.8b,
l.sub.9a>l.sub.9b, and l.sub.10a>l.sub.10b. Thus, the
S-shaped curve propagates proximally along the length of the
automatically controlled proximal portion 106 of the endoscope body
102. The S-shaped curve appears to be fixed in space, as the
endoscope body 102 advances distally.
[0043] Similarly, when the endoscope body 102 is withdrawn
proximally, each time the endoscope body 102 is moved proximally by
one unit, each section in the automatically controlled proximal
portion 106 is signaled to assume the shape of the section that
previously occupied the space that it is now in. The S-shaped curve
propagates distally along the length of the automatically
controlled proximal portion 106 of the endoscope body 102, and the
S-shaped curve appears to be fixed in space, as the endoscope body
102 withdraws proximally.
[0044] Whenever the endoscope body 102 is advanced or withdrawn,
the axial motion transducer 150 detects the change in position and
the electronic motion controller 140 propagates the selected curves
proximally or distally along the automatically controlled proximal
portion 106 of the endoscope body 102 to maintain the curves in a
spatially fixed position. This allows the endoscope body 102 to
move through tortuous curves without putting unnecessary force on
the wall of the colon C.
[0045] FIG. 8 shows a representative portion of an alternative
endoscopic body embodiment 190 which has multiple segments 192
interconnected by joints 194. In this embodiment, adjacent segments
192 can be moved or angled relative to one another by a joint 194
having at least one degree-of-freedom, and preferably having
multiple degrees-of-freedom, preferably about two axes as shown
here. As seen further in FIG. 9, a partial schematic representation
196 of the embodiment 190 is shown where two segments 192 may be
rotated about joint 194 about the two independent axes. The range
of motion may be described in relation to spherical axes 198 by
angles .alpha. and .beta..
[0046] As mentioned above, such a segmented body may be actuated by
a variety of methods. A preferable method involves the use of
electromechanical motors individually mounted on each individual
segment to move the segments relative to one another. FIG. 10 shows
a preferable embodiment 200 having motorized segmented joints. Each
segment 192 is preferably comprised of a backbone segment 202,
which also preferably defines at least one lumen running through it
to provide an access channel through which wires, optical fibers,
air and/or water channels, various endoscopic tools, or any variety
of devices and wires may be routed through. The backbone segment
may be made of a variety of materials which are preferably
biocompatible and which provide sufficient strength to support the
various tools and other components, e.g., stainless steel. Although
much of the description is to an individual segment 192, each of
the segments 192 are preferably identical, except for the segment
(or first few segments) located at the distal tip, and the
following description readily applies to at least a majority of the
segments 192.
[0047] A single motor, or multiple motors depending upon the
desired result and application, may be attached to at least a
majority of the segments. An embodiment having a single motor on a
segment is illustrated in FIG. 10 where an individual motor 204 is
preferably attached to backbone 202 and is sufficiently small and
compact enough so as to present a relatively small diameter which
is comfortable and small enough for insertion into a patient
without trauma. Motor 204, which is shown here as being a small
brushed DC motor, may be used for actuating adjacent segments 192
and may be controlled independently from other motors. Various
motors, aside from small brushed DC motors, may also be used such
as AC motors, linear motors, etc. Each motor 204 also preferably
contains within the housing not only the electromechanical motor
assembly EM itself, but also a gear reduction stage GR, and a
position encoder PE. A gear reduction stage GR attached to the
motor assembly EM will allow for the use of the motor 204 in its
optimal speed and torque range by changing high-speed, low-torque
operating conditions into a more useful low-speed, high-torque
output. The position encoder PE may be a conventional encoder to
allow the controlling computer to read the position of the
segment's joint 194 by keeping track of the angular rotational
movement of the output shaft of the motor 204.
[0048] Each motor 204 has a rotatable shaft which extends from an
end of the motor 204 to provide for the transmission of power to
actuate the segments 192. Upon this shaft, a spool 206 may be
rotatingly attached with a first end of the cable 208 further wound
about the spool 206. The cable 208 may then be routed from spool
206 through a channel 212 which is defined in the cable guide 210
and out through opening 214 (as seen in greater detail in FIGS.
11A-11B) to cable anchor 216, to which the second end of the cable
208 is preferably attached, e.g., by crimping and/or soldering. The
cable guide 210 serves to capture the cable 208 that is wound about
the spool 206. The cable anchor 216 is attached across a universal
joint pivot 220 to an adjacent segment 192 via a pin 218 and may be
shaped like a conventional electronic ring connector having a round
section defining a hole therethrough for mounting to the segment
192 and an extension protruding from the anchor 216 for attaching
the second end of the cable 208. Cable 208 may comprise a wide
variety of filaments, strands, wires, chains, braids, etc. any of
which may be made of a wide variety of biocompatible materials,
e.g., metals such as stainless steel, polymers such as plastics and
Nylon, etc.
[0049] In operation, when the motor 204 is operated to spin the
shaft in a first direction, e.g., clockwise, the spool 206 rotates
accordingly and the cable 208 pulls in a corresponding direction on
the adjacent segment 192 and transmits the torque to subsequently
actuate it along a first axis. When the motor 204 is operated to
spin the shaft in a second direction opposite to the first, e.g.,
counter-clockwise, the spool 206 again rotates accordingly and the
cable 208 would then pull in the corresponding opposing direction
on the adjacent segment 192 to subsequently transmit the torque and
actuate it in the opposite direction.
[0050] FIGS. 11A and 11B show exploded isometric assembly views of
two adjacent segments and an individual segment, respectively, from
the embodiment shown in FIG. 10. As seen in FIG. 11A, backbone 202
is seen with the lumen 221, which may be used to provide a working
channel, as described above. Also seen are channel 212 defined in
cable guide 210 as well as opening 214 for the cable 208 to run
through. In interconnecting adjacent segments and to provide the
requisite degree-of-freedom between segments, a preferable method
of joining involves using the universal joint pivot 220. However,
other embodiments, rather than using a universal joint pivot 220,
may use a variety of joining methods, e.g., a flexible tube used to
join two segments at their respective centers, a series of single
degree-of-freedom joints that may be closely spaced, etc. This
particular embodiment describes the use of the universal joint
pivot 220. At the ends of backbone 202 adjacent to other segments,
a pair of universal yoke members 224 may be formed with a pair of
corresponding pin openings 226. As the universal joint pivot 220 is
connected to a first pair of yoke members 224 on one segment, a
corresponding pair of yoke members 224 from the adjacent segment
may also be attached to the joint pivot 220.
[0051] As seen further in FIG. 11B, the universal joint pivot 220
is shown in this embodiment as a cylindrical ring having two sets
of opposing receiving holes 228 for pivotally receiving
corresponding yoke members 224. The receiving holes 228 are shown
as being spaced apart at 90.degree. intervals, however, in other
variations, receiving holes may be spaced apart at other angles
depending upon the desired degree-of-freedom and application. Also
seen is an exploded assembly of spool 206 removed from motor 204
exposing drive shaft 205. With motor 204 displaced from backbone
202, the groove 230 is revealed as formed in the backbone 202. This
groove 230 may be depressed in backbone 202 to preferably match the
radius of the motor 204 housing not only to help locate the motor
204 adjacent to backbone 202, but also to help in reducing the
overall diameter of the assembled segment. The motor 204 may be
attached to the backbone 202 by various methods, e.g., adhesives,
clamps, bands, mechanical fasteners, etc. A notched portion 232 may
also be formed in the cable guide 210 as shown to help in further
reducing segment diameter.
[0052] Prior to insertion into a patient, the endoscope 200 may be
wound onto the rotating drum 184 within the rotary housing 180 of
FIG. 5 for storage and during use, where it may optionally be
configured to have a diagnostic check performed automatically. When
the endoscope 200 is wound onto the drum 184, adjacent segments 192
will have a predetermined angle relative to one another, as
determined initially by the diameter of the drum 184 and the
initial configuration of the storage unit in which the endoscope
200 may be positioned. During a diagnostic check before insertion,
a computer may be configured to automatically sense or measure the
angles between each adjacent segments 192. If any of the adjacent
segments 192 indicate a relative measured angle out of a
predetermined acceptable range of angles, this may indicate a
segment 192 being out of position and may indicate a potential
point of problems during endoscope 200 use. Accordingly, the
computer may subsequently sound an audible or visual alarm and may
also place each of the segments 192 into a neutral position to
automatically prevent further use or to prevent any trauma to the
patient.
[0053] FIGS. 12-17 show the endoscope 100 of the present invention
being employed for a colonoscopic examination of a patient's colon.
In FIG. 12, the endoscope body 102 has been lubricated and inserted
into the patient's colon C through the anus A. The distal end 108
of the endoscope body 102 is advanced through the rectum R until
the first turn in the colon C is reached, as observed through the
ocular 124 or on a video monitor. To negotiate the turn, the
selectively steerable distal portion 104 of the endoscope body 102
is manually steered toward the sigmoid colon S by the user through
the steering control 122. The control signals from the steering
control 122 to the selectively steerable distal portion 104 are
monitored by the electronic motion controller 140. When the correct
curve of the selectively steerable distal portion 104 for advancing
the distal end 108 of the endoscope body 102 into the sigmoid colon
S has been selected, the curve is logged into the memory of the
electronic motion controller 140 as a reference. This step can be
performed in a manual mode, in which the user gives a command to
the electronic motion controller 140 to record the selected curve,
using keyboard commands or voice commands. Alternatively, this step
can be performed in an automatic mode, in which the user signals to
the electronic motion controller 140 that the desired curve has
been selected by advancing the endoscope body 102 distally. In this
way, a three dimensional map of the colon or path may be generated
and maintained for future applications.
[0054] Whether operated in manual mode or automatic mode, once the
desired curve has been selected with the selectively steerable
distal portion 104, the endoscope body 102 is advanced distally and
the selected curve is propagated proximally along the automatically
controlled proximal portion 106 of the endoscope body 102 by the
electronic motion controller 140, as described above. The curve
remains fixed in space while the endoscope body 102 is advanced
distally through the sigmoid colon S. In a particularly tortuous
colon, the selectively steerable distal portion 104 may have to be
steered through multiple curves to traverse the sigmoid colon
S.
[0055] As illustrated in FIG. 13, the user may stop the endoscope
100 at any point for examination or treatment of the mucosal
surface or any other features within the colon C. The selectively
steerable distal portion 104 may be steered in any direction to
examine the inside of the colon C. When the user has completed the
examination of the sigmoid colon S, the selectively steerable
distal portion 104 is steered in a superior direction toward the
descending colon D. Once the desired curve has been selected with
the selectively steerable distal portion 104, the endoscope body
102 is advanced distally into the descending colon D, and the
second curve as well as the first curve are propagated proximally
along the automatically controlled proximal portion 106 of the
endoscope body 102, as shown in FIG. 14.
[0056] If, at any time, the user decides that the path taken by the
endoscope body 102 needs to be revised or corrected, the endoscope
100 may be withdrawn proximally and the electronic motion
controller 140 commanded to erase the previously selected curve.
This can be done manually using keyboard commands or voice commands
or automatically by programming the electronic motion controller
140 to go into a revise mode when the endoscope body 102 is
withdrawn a certain distance. The revised or corrected curve is
selected using the selectively steerable distal portion 104, and
the endoscope body 102 is advanced as described before.
[0057] The endoscope body 102 is advanced through the descending
colon D until it reaches the left (splenic) flexure F.sub.l of the
colon. Here, in many cases, the endoscope body 102 must negotiate
an almost 180 degree hairpin turn. As before, the desired curve is
selected using the selectively steerable distal portion 104, and
the endoscope body 102 is advanced distally through the transverse
colon T, as shown in FIG. 15. Each of the previously selected
curves is propagated proximally along the automatically controlled
proximal portion 106 of the endoscope body 102. The same procedure
is followed at the right (hepatic) flexure Fr of the colon and the
distal end 108 of the endoscope body 102 is advanced through the
ascending colon G to the cecum E, as shown in FIG. 16. The cecum E,
the ileocecal valve V and the terminal portion of the ileum I can
be examined from this point using, the selectively steerable distal
portion 104 of the endoscope body 102.
[0058] FIG. 17 shows the endoscope 100 being withdrawn through the
colon C. As the endoscope 100 is withdrawn, the endoscope body 102
follows the previously selected curves by propagating the curves
distally along the automatically controlled proximal portion 106,
as described above. At any point, the user may stop the endoscope
100 for examination or treatment of the mucosal surface or any
other features within the colon C using the selectively steerable
distal portion 104 of the endoscope body 102. At any given time,
the endoscope 100 may be withdrawn or back-driven by a desired
distance.
[0059] In one preferred method according to the present invention,
the electronic motion controller 140 includes an electronic memory
in which is created a three-dimensional mathematical model of the
patient's colon or other anatomy through which the endoscope body
102 is maneuvered. The three-dimensional model can be annotated by
the operator to record the location of anatomical landmarks,
lesions, polyps, biopsy samples and other features of interest. The
three-dimensional model of the patient's anatomy can be used to
facilitate reinsertion of the endoscope body 102 in subsequent
procedures. In addition, the annotations can be used to quickly
find the location of the features of interest. For example, the
three-dimensional model can be annotated with the location where a
biopsy sample was taken during an exploratory endoscopy. The site
of the biopsy sample can be reliably located again in follow-up
procedures to track the progress of a potential disease process
and/or to perform a therapeutic procedure at the site.
[0060] In one particularly preferred variation of this method, the
electronic motion controller 140 can be programmed, based on the
three-dimensional model in the electronic memory, so that the
endoscope body 102 will automatically assume the proper shape to
follow the desired path as it is advanced through the patient's
anatomy. In embodiments of the steerable endoscope 100 that are
configured for automatically advancing and withdrawing the
endoscope body 102, as described above in connection with FIGS. 3,
4 and 5, the endoscope body 102 can be commanded to advance
automatically though the patient's anatomy to the site of a
previously noted lesion or other point of interest based on the
three-dimensional model in the electronic memory.
[0061] Imaging software would allow the three-dimensional model of
the patient's anatomy obtained using the steerable endoscope 100 to
be viewed on a computer monitor or the like. This would facilitate
comparisons between the three-dimensional model and images obtained
with other imaging modalities, for example fluoroscopy,
radiography, ultrasonography, magnetic resonance imaging (MRI),
computed tomography (CT scan), electron beam tomography or virtual
colonoscopy. Conversely, images from these other imaging modalities
can be used to map out an approximate path or trajectory to
facilitate insertion of the endoscope body 102. In addition, images
from other imaging modalities can be used to facilitate locating
suspected lesions with the steerable endoscope 100. For example,
images obtained using a barium-contrast radiograph of the colon can
be used to map out an approximate path to facilitate insertion of
the endoscope body 102 into the patient's colon. The location and
depth of any suspected lesions seen on the radiograph can be noted
so that the endoscope body 102 can be quickly and reliably guided
to the vicinity of the lesion.
[0062] Imaging modalities that provide three-dimensional
information, such as biplanar fluoroscopy, CT or MRI, can be used
to program the electronic motion controller 140 so that the
endoscope body 102 will automatically assume the proper shape to
follow the desired path as it is advanced through the patient's
anatomy. In embodiments of the steerable endoscope 100 that are
configured for automatically advancing and withdrawing the
endoscope body 102, the endoscope body 102 can be commanded to
advance automatically though the patient's anatomy along the
desired path as determined by the three-dimensional imaging
information. Similarly, the endoscope body 102 can be commanded to
advance automatically to the site of a suspected lesion or other
point of interest noted on the images.
[0063] As described above, the axial motion transducer 150 can be
made in many possible configurations, e.g., shown in FIG. 2 as a
ring 152. It functions partially as a fixed point of reference or
datum to produce a signal indicative of the axial position of the
endoscope body 102 with respect to the fixed point of reference.
The axial motion transducer 150 may use optical, electronic or
mechanical methods to measure the axial position of the endoscope
body 102. One preferable embodiment of the datum 234 is shown
schematically in FIGS. 18-20 as an instrumented speculum which may
be placed partially into the rectum of the patient or at least
adjacent to the anus A of a patient. Prior to the segmented
endoscopic body 238 being inserted into the anus A, it is
preferably first passed through the datum channel 236 of datum 234.
The datum 234 may house the electronics and mechanical assemblies
necessary to measure the depth of insertion, as discussed below,
and it may also provide a fixed, solid base to aid in co-locating
the endoscopic body 238 adjacent to the anus A or body orifice as
well as provide a base to stabilize and insert the endoscope body
238 into the orifice. The instrumented speculum may be constructed
of a biocompatible material, such as injection-molded plastic, and
house inexpensive electronics, as the speculum may preferably be
disposable.
[0064] As the endoscopic body 238 passes through the datum channel
236, one preferable optical method of measuring the depth of
insertion and axial position may involve measurement through the
use of reflective infra-red sensors mounted on the datum 234. The
outer surface of the endoscopic body 238 may have hatch marks or
some other indicative or reflective marking placed at known
intervals along the body 238. As the endoscopic body 238 is
advanced or withdrawn through the anus A and the datum channel 236,
an optical sensor can read or sense the hatch marks and increment
or decrement the distance traveled by the endoscopic body
accordingly. Thus, a sensor reading such marks may have an output
that registers as a logic-level "1" or "ON" when a mark is sensed
and a logic-level "0" or "OFF" when no mark is sensed. By counting
or tracking the number of 1-to-0 transitions on a sensor output,
the depth may be measured accordingly. Thus resolution of the depth
measurement may be determined in part in this embodiment by the
spacing between the hatch marks.
[0065] A simplified representation of how the distance may be used
to advance the device may be seen in FIG. 18. The endoscopic body
238 is advanced until the distal tip reaches a depth of L.sub.1, as
measured from the midpoint of the datum speculum 234. At this
depth, it is necessary for the user to selectively steer the tip to
follow the sigmoid colon S such that the body forms a radius of
curvature R.sub.1. Once the position and depth of this feature has
been defined by the distal tip, any proximal segment that reaches
this depth of L.sub.1 can be commanded to configure itself in the
same manner as the distal tip segment until it has achieved the
correct combination of bends to negotiate the turn. As the body 238
is further advanced, as seen in FIG. 19, it will eventually reach
the second major bend at a depth of L.sub.1+L.sub.2. Accordingly,
as for L.sub.1, any segment that is advanced and reaches a depth of
L.sub.1+L.sub.2 will likewise be commanded to execute a turn as
defined by the distal tip being selectively steered when it first
passed the second bend into the descending colon D. Again as the
body 238 is further advanced, as shown in FIG. 20, any subsequent
segment that is advanced to reach a depth of
L.sub.1+L.sub.2+L.sub.3 will be commanded to execute and negotiate
the turn to follow the transverse colon T, again where the original
curve has been defined by the selectively steerable distal tip.
[0066] FIG. 21 shows a schematic of one embodiment of a control
system which may be used to control and command the individual
segments of a segmented endoscopic device of the type shown in
FIGS. 8-11B. As seen, a master controller 248, which preferably
resides at a location away from the segmented endoscope 242, may be
used to control and oversee the depth measurement as the endoscope
242 is inserted 256 into a patient. The master controller 248 may
also be used to manage and communicate the actuation efforts of
each of the joints and segments 242.sub.1 to 242.sub.n by remaining
in electrical communication through communications channels 252,
which may include electrical wires, optical fibers, wireless
transmission, etc. As also shown in this embodiment, the master
controller 248 may also be in communication with datum 244 via
datum communication channel 254 to measure and track the depth of
insertion of the endoscope 242 as it passes through datum channel
246, as described above.
[0067] The segmented embodiment 242 may be comprised of a number of
individual segments 242.sub.1 to 242.sub.n (only segments 242, to
2425 are shown for clarity). Each segment 242.sub.1 to 242.sub.n
preferably has its own separate controller 250.sub.1 to 250.sub.n,
respectively, contained within each segment. Types of controllers
used may include microcontrollers. The controllers 250.sub.1 to
250.sub.n may serve to perform several functions, e.g., measuring
the angle of each segment joint in each of the two axes .alpha. and
.beta., as described above, activating the motors contained within
the segments 242.sub.1 to 242.sub.n to actuate endoscope 242
movement, and receiving and handling commands issued from the
master controller 248. Having individual controllers 250.sub.1 to
250.sub.n in each respective segment 242.sub.1 to 242.sub.n enables
each segment to manage the requirements for a given configuration
locally at the controller level without oversight from the master
controller 248 after a command has been issued.
[0068] Accordingly, a flow chart embodiment for the master
controller algorithm 260, as shown in FIG. 22, may be used to
control the overall function during insertion into a patient.
During an initial step 262, the overall system (such as that shown
in FIG. 21) may be initialized where all position sensors are
zeroed. The master controller 248 then enters a waiting state where
it continually monitors the depth measurement gathered by the datum
244 located proximally of body opening, as shown in step 264. Once
movement, i.e., depth measurement, is detected by the datum 244 in
step 264, the master controller 248 then determines whether the
direction of motion of the endoscopic body 242 is being advanced,
i.e., inserted, or withdrawn. As shown in step 266, if the
endoscopic body 242 is being inserted and the depth is increasing,
the current depth is incremented, as in step 268; otherwise, the
current depth is decremented, as in step 270. Once the depth has
been determined, the master controller 248 communicates to each
segment 242.sub.1 to 242.sub.n individually and commands each to
actuate to adjust or correct its position relative to the adjacent
segments for the current depth, as shown in step 272. Afterwards,
the master controller 248 continues to monitor any changes in depth
and the process is repeated as shown.
[0069] To maintain the orientation of each axis .alpha. and .beta.
and the positioning and the depth of each segment 242.sub.1 to
242.sub.n, a data array, or similar data structure, may be used by
the master controller 248 to organize the information, as shown in
the following Table 1. Depth index D.sub.1 to D.sub.n is used here
to denote the individual hatch marks, as seen in FIG. 21, and the
distance between the hatch marks is a known value. Thus, the
resolution with which the endoscope 242 can maintain its shape may
depend at least in part upon the spacing between the depth indices
D.sub.1 to D.sub.n. Moreover, the number and spacing of the indices
D.sub.1 to D.sub.n may be determined and set according to the
specific application and necessary requirements. Additional
smoothing algorithms may be used and implemented to further create
gradual transitions between segments 242.sub.1 to 242.sub.n or
between discrete depth measurement indices D.sub.1 to D.sub.n.
TABLE-US-00001 TABLE 1 Data array of individual segments. Segment 1
Segment 2 Segment N Depth Index .alpha./.beta. .alpha./.beta. . . .
.alpha./.beta. D.sub.1 .alpha..sub.D1/.beta..sub.D1
.alpha..sub.D1/.beta..sub.D1 . . . .alpha..sub.D1/.beta..sub.D1
D.sub.2 .alpha..sub.D2/.beta..sub.D2 .alpha..sub.D2/.beta..sub.D2 .
. . .alpha..sub.D2/.beta..sub.D2 D.sub.3
.alpha..sub.D3/.beta..sub.D3 .alpha..sub.D3/.beta..sub.D3 . . .
.alpha..sub.D3/.beta..sub.D3 . . . . . . . . . . . . . . . D.sub.n
.alpha..sub.Dn/.beta..sub.Dn .alpha..sub.Dn/.beta..sub.Dn . . .
.alpha..sub.Dn/.beta..sub.Dn
[0070] FIG. 23 shows a flowchart embodiment of the segment
controller algorithm 280. While the master controller 248 manages
the measurement of the overall depth of insertion of the endoscope
242 and determines the overall shape, it may also communicate with
the individual controllers 250.sub.1 to 250.sub.n in each segment
242.sub.1 to 242.sub.n, respectively, so that the computation task
of managing the motion of the entire system is preferably
distributed.
[0071] As discussed above, the individual controllers 250.sub.1 to
250.sub.n may serve a variety of functions, including accepting
commands from the master controller 248, managing communications
with other controllers as necessary, measuring and controlling the
position of individual segments 242.sub.1 to 242.sub.n, and
performing diagnostics, error checking, etc., among other things.
The algorithm to control each segment 242.sub.1 to 242.sub.n is
preferably similar for each segment; although the lead segment
242.sub.1 or first few segments are under the guidance of the
physician to selectively control and steer so that the desired
curve is set for an appropriate path to be followed
[0072] The initial step 282 for the system preferably first occurs
where all communications, actuator (or motor), position sensors,
and orientation are initialized. The controllers 250.sub.1 to
250.sub.n may then wait to receive any communications from the
master controller 248 in step 284. If no communications are
received, the controllers 250.sub.1 to 250.sub.n preferably enter
into a main loop while awaiting commands. When a command is
received, each of the controllers 250.sub.1 to 250.sub.n may
request diagnostic data, as in step 286. If diagnostic data is
requested, the appropriate diagnostics are performed in step 288
and the results are sent back to the master controller 248, as in
step 290. If no diagnostic data is requested in step 286, each of
the controllers 250.sub.1 to 250.sub.n in step 292 may then
determine whether actuation or motion has been requested by the
master controller 248. If no actuation or motion has been
requested, the relevant segment may continue to receive a command;
otherwise, the relevant segment determines whether a command has
been issued affecting the segment axis .alpha., as in step 294, or
segment axis .beta., as in step 300. If the segment axis .alpha. is
to be altered, the command is sent to the .alpha. axis PID
controller (or to a superior control scheme) in step 296, and the
appropriate actuator is subsequently activated effecting the
actuation of the segment in the .alpha. axis, as in step 298.
Likewise, if the segment axis .beta. is to be altered, either alone
or in conjunction with the .alpha. axis, the command is sent to the
.beta. axis PID controller (or to a superior control scheme) in
step 302, and the appropriate actuator is subsequently activated
effecting the actuation of the segment in the .beta. axis, as shown
in step 304. Once the appropriate commands have been effectuated,
the controllers 250.sub.1 to 250.sub.n again enter the main loop to
await any further commands.
[0073] Although the endoscope of the present invention has been
described for use as a colonoscope, the endoscope can be configured
for a number of other medical and industrial applications. In
addition, the present invention can also be configured as a
catheter, cannula, surgical instrument or introducer sheath that
uses the principles of the invention for navigating through
tortuous body channels.
[0074] In a variation of the method that is particularly applicable
to laparoscopy or thoracoscopy procedures, the steerable endoscope
100 can be selectively maneuvered along a desired path around and
between organs in a patient's body cavity. The distal end 108 of
the endoscope 100 is inserted into the patient's body cavity
through a natural opening, through a surgical incision or through a
surgical cannula, introducer, or trocar. The selectively steerable
distal portion 104 can be used to explore and examine the patient's
body cavity and to select a path around and between the patient's
organs. The electronic motion controller 140 can be used to control
the automatically controlled proximal portion 106 of the endoscope
body 102 to follow the selected path and, if necessary, to return
to a desired location using the three-dimensional model in the
electronic memory of the electronic motion controller 140.
[0075] A further variation which involves a non-contact method of
measurement and tracking of the steerable endoscope is seen in
FIGS. 24 to 26. This variation may be used in conjunction with
sensor-based systems or transponders, e.g., coils or magnetic
sensors, for tracking of the endoscope via magnetic detection
technology or a navigational system or device external to the
patient employing a scheme similar to that used in global
positioning systems (GPS). Magnetic sensors may be used, but coils
are preferable because of their ability to resonate at distinct
frequencies as well as their ability to have a unique "signature",
which may allow for the use of several different coils to be used
simultaneously. Seen in FIG. 24, the endoscopic body 238 may be
inserted into a patient via the anus A. Located on the endoscope
body 238 are transponders 310 to 318 which may be placed at
predetermined positions such as the selectively steerable distal
tip.
[0076] As the endoscope 238 is advanced through the descending D
and transverse colon T, the transponders may be detected by an
external navigational unit 320 which may have a display 322 showing
the position of the endoscope 238 within the patient. As the
endoscope 238 is further advanced within the patient, as seen in
FIG. 26, the navigational unit 320 may accordingly show the
corresponding movement. The use of a navigational unit 320 presents
a non-contact method of navigating a device such as the endoscope
238 and may be used to measure and locate different positions
within the patient relative to anatomical landmarks, such as the
anus A or ileocecal valve. Furthermore, such an embodiment may be
used either alone or in conjunction with the datum speculum 234
instrumentation as described above.
[0077] Use of the navigational unit 320 may also be particularly
applicable to laparoscopy or thoracoscopy procedures, as described
above, in spaces within the body other than the colon. For example,
the endoscope 238 may also be selectively maneuvered along a
desired path around and between organs in a patient's body cavity
through any of the openings into the body discussed above. While
being maneuvered through the body cavity, the endoscope 238 may be
guided and tracked by the externally located navigational unit 320
while the endoscope's 238 location may be electronically marked and
noted relative to a predetermined reference point, such as the
datum, or relative to anatomical landmarks, as described above.
[0078] While the present invention has been described herein with
respect to the exemplary embodiments and the best mode for
practicing the invention, it will be apparent to one of ordinary
skill in the art that many modifications, improvements and
subcombinations of the various embodiments, adaptations and
variations can be made to the invention without departing from the
spirit and scope thereof.
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