U.S. patent application number 12/425272 was filed with the patent office on 2010-04-15 for tendon-driven endoscope and methods of use.
Invention is credited to Scott C. Anderson, Amir Belson, Christopher A. Julian, Wade A. Keller, Robert M. Ohline, Alex T. Roth, Joseph M. Tartaglia.
Application Number | 20100094088 12/425272 |
Document ID | / |
Family ID | 31976259 |
Filed Date | 2010-04-15 |
United States Patent
Application |
20100094088 |
Kind Code |
A1 |
Ohline; Robert M. ; et
al. |
April 15, 2010 |
TENDON-DRIVEN ENDOSCOPE AND METHODS OF USE
Abstract
A steerable, tendon-driven endoscope is described herein. The
endoscope has an elongated body with a manually or selectively
steerable distal portion and an automatically controlled, segmented
proximal portion. The steerable distal portion and the segment of
the controllable portion are actuated by at least two tendons. As
the endoscope is advanced, the user maneuvers the distal portion,
and a motion controller actuates tendons in the segmented proximal
portion so that the proximal portion assumes the selected curve of
the selectively steerable distal portion. By this method the
selected curves are propagated along the endoscope body so that the
endoscope largely conforms to the pathway selected. When the
endoscope is withdrawn proximally, the selected curves can
propagate distally along the endoscope body. This allows the
endoscope to negotiate tortuous curves along a desired path through
or around and between organs within the body.
Inventors: |
Ohline; Robert M.; (Redwood
City, CA) ; Tartaglia; Joseph M.; (Morgan Hill,
CA) ; Belson; Amir; (Los Altos, CA) ; Roth;
Alex T.; (Redwood City, CA) ; Keller; Wade A.;
(Aliso Viejo, CA) ; Anderson; Scott C.;
(Sunnyvale, CA) ; Julian; Christopher A.; (Los
Gatos, CA) |
Correspondence
Address: |
PATENT DEPT.;INTUITIVE SURGICAL, INC
1266 KIFER ROAD BLDG 101
SUNNYVALE
CA
94086
US
|
Family ID: |
31976259 |
Appl. No.: |
12/425272 |
Filed: |
April 16, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11019963 |
Dec 20, 2004 |
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12425272 |
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10229577 |
Aug 27, 2002 |
6858005 |
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11019963 |
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Current U.S.
Class: |
600/118 |
Current CPC
Class: |
A61B 1/0057 20130101;
A61B 5/065 20130101; A61B 1/0058 20130101; A61B 1/0016 20130101;
A61B 1/00006 20130101; A61B 2034/301 20160201; A61B 1/00128
20130101; A61B 2034/742 20160201; A61B 1/31 20130101; A61B 1/0053
20130101; A61B 1/00057 20130101; A61B 2034/741 20160201; A61B 1/01
20130101 |
Class at
Publication: |
600/118 |
International
Class: |
A61B 1/005 20060101
A61B001/005 |
Claims
1. An apparatus for insertion into a body cavity comprising: An
elongated body comprising a steerable distal portion and a
plurality of automatically controlled segments proximal to the
steerable distal portion that are articulatable relative to one
another; a plurality of tensioning members each attached proximally
to an actuator and distally to one of the plurality of
automatically controlled segments; a steering controller that
allows a user to selectively steer the steerable distal portion;
and a motion controller that controls the actuator to bend the
plurality of automatically controlled segments to follow a path
defined by the steerable distal portion.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 11/019,963, filed Dec. 20, 2004 entitled
"TENDON-DRIVEN ENDOSCOPE AND METHODS OF USE", which is a
continuation of U.S. patent application Ser. No. 10/229,577 filed
Aug. 27, 2002, entitled "TENDON-DRIVEN ENDOSCOPE AND METHODS OF
INSERTION", now U.S. Pat. No. 6,858,055.
INCORPORATION BY REFERENCE
[0002] All publications and patent applications mentioned in this
specification are herein incorporated by reference to the same
extent as if each individual publication or patent application was
specifically and individually indicated to be incorporated by
reference.
FIELD OF THE INVENTION
[0003] The present invention relates generally to endoscopes and
endoscopic 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
[0004] 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.
[0005] 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.
[0006] 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 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,
and can result in looping of 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.
[0007] 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. 4,054,128; 4,543,090; 4,753,223; 4,873,965; 5,174,277;
5,337,732; 5,383,852; 5,487,757; 5,624,380; and 5,662,587. 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.
[0008] 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.
[0009] 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 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,
and can result in looping of 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.
[0010] 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. 4,054,128; 4,543,090; 4,753,223; 4,873,965; 5,174,277;
5,337,732; 5,383,852; 5,487,757; 5,624,380; and 5,662,587.
SUMMARY OF THE INVENTION
[0011] The present invention relates . . . The following is a
description of steerable endoscopes for the examination of a
patient's colon, other internal bodily cavities, or other internal
body spaces with minimal impingement upon the walls of those
organs. One variation of the steerable endoscope described herein
has a segmented, elongated body with a manually or selectively
steerable distal portion (at least one segment) and an
automatically controlled proximal portion. The selectively
steerable distal portion can be flexed in any direction by
controlling the tension on tendons, e.g., cables, wires, etc., from
their proximal ends; these tendons are routed selectively
throughout the length of the endoscope. The controllable proximal
portion of the endoscope contains at least one independently
articulatable segment that can also be bent in any direction via
the tendons, and can be made to assume the shape of the distal
segment as the endoscope is advanced distally.
[0012] The selectively steerable distal portion can be selectively
steered (or bent) up to, e.g., a full 180 degrees, in any
direction. A fiberoptic imaging bundle and one or more illumination
fibers may extend through the body from the proximal portion to the
distal portion. The illumination fibers are preferably in
communication with a light source, i.e., conventional light
sources, which may be positioned at some external location, or
other sources such as LEDs. Alternatively, the endoscope may be
configured as a video endoscope with a miniature video camera, such
as a CCD camera, positioned at the distal portion of the endoscope
body. The video camera may be used in combination with the
illumination fibers. Optionally, the body of the endoscope may also
include one or two access lumens that may be used, for example,
for: insufflation or irrigation, air and water channels, and vacuum
channels, etc. Generally, the body of the endoscope is highly
flexible so that it is able to bend around small diameter curves
without buckling or kinking while maintaining the various channels
intact. The endoscope can be made in a variety of sizes and
configurations for other medical and industrial applications.
[0013] In operation, the steerable distal portion of the endoscope
may be first advanced into the patient's rectum via the anus. The
endoscope may be simply advanced, either manually or automatically
by a motor, until the first curvature is reached. At this point,
the user (e.g., a physician or surgeon) can actively control the
steerable distal portion to attain an optimal curvature or shape
for advancement of the endoscope. The optimal curvature or shape is
the path that presents the least amount of contact or interference
from the walls of the colon. In one variation, once the desired
curvature has been determined, the endoscope may be advanced
further into the colon such that the automatically controlled
segments of the controllable portion follow the distal portion
while transmitting the optimal curvature or shape proximally down
the remaining segments of the controllable portion. Thus, as the
instrument is advanced, it follows the path that the distal portion
has defined. The operation of the controllable segments will be
described in further detail below.
[0014] Tendons, also called tensioning members, may be used to
articulate the controllable segments of the endoscope, including
the distal steerable portion. Examples of appropriate tendons are
push-pull cables that are flexible but minimally compressible or
extensible. In one variation, this tendon is a Bowden cable where
an internal cable is typically coaxially surrounded by a housing or
sleeve through which the cable is free to move. Bowden cables can
be used to apply either tensile or compressive forces in order to
articulate the endoscope and can be actuated remotely to deliver
forces as desired at locations on the endoscope.
[0015] In one variation using Bowden push-pull cables for the
tendons, three tendons may be attached at sites equally spaced
around the circumference of the controllable endoscope segment.
Another variation may alternatively use two tendons, as described
further below. The sleeves of the Bowden cables may be affixed at
the proximal end of the segment, and the internal cables may be
attached to the distal end of the same segment. Applying a tensile
or compressive force to one of these internal cables causes the
segment to bend in the direction of the cable being pushed or
pulled. The bending is continuous and proportional to the
displacement of the cable. Thus, a segment can be bent in virtually
any direction using tendons by applying tension or compression on
one or a combination of tendons attached to the distal end of the
segment. Other variations of this invention using Bowden cables may
use four or more Bowden cables spaced either equally or in
specified positions around the circumference of the segment to be
bent depending upon the desired articulation. A further variation
may even use two Bowden cables in combination with biasing
elements, e.g., springs, elastic elements, pistons, etc., to
articulate the segments.
[0016] Another variation of the tendon uses a non-compressible,
non-extensible push-pull cable in compression rather than in
tension in order to bend a segment. Alternatively, a combination of
tendons under both compression and tension could also be used.
[0017] The controllable proximal portion of the endoscope is
comprised of at least one segment and preferably many segments that
are each articulatable relative to one another via a controller
and/or a computer located at a distance from the endoscope. In one
variation, the majority of the insertable length of the endoscope
comprises controllable segments. Segments are preferably
non-compressible and non-expansible, and therefore maintain a
constant length along their centerline when bending. An example
describing such a variation may be found in U.S. patent application
Ser. No. 09/790,204 entitled "Steerable Endoscope and Improved
Method of Insertion", which is commonly owned and incorporated
herein by reference in its entirety. Each of the segments may have
tendons to allow for controlled motion of the segments in space.
Thus, coordinating the articulation of individual tendons can bend
each segment across a wide range of motion. Individual tendons can
be actuated by, for example, an electromechanical motor operably
connected to the proximal end of the tendon. Alternatively,
pneumatic or hydraulic cylinders, pneumatic or hydraulic motors,
solenoids, shape memory alloy wires, or electronic rotary actuators
could be utilized to actuate the segments using the tendons.
[0018] Another variation of the endoscope uses ring-shaped support
pieces, or vertebrae, as control rings to achieve bendable
segments. A segment is comprised of a plurality of adjacent or
stacked vertebrae where the vertebrae are connected to each other
by jointed sections, e.g., hinged joints, giving the segment
flexibility in any direction. Thus, vertebra-type control rings can
be hinged to adjacent vertebrae by flanges with through holes. In
one variation, pairs of hinge joints project perpendicularly from
the face of each vertebra and can connect to the hinge joints of
adjacent vertebrae both proximally and distally. Each pair of hinge
joints allows limited motion in one axis. The hinge joints
projecting from the opposite face of the vertebra are preferably
located 90 degrees in rotation from the pair on the other face of
the vertebra. This creates a second axis of motion in a plane
perpendicular to the first. Adding additional vertebrae in this way
result in a segment that could be bent in any direction. For
example, approximately ten vertebrae could be linked to create one
such segment. Other variations can have more or fewer vertebrae per
segment.
[0019] In addition to hinged joints; there are other features that
could be included in the control ring. Thus, the inner surface of
the vertebra could have channels forming a common lumen in the
endoscope, such as for the working channels, the air and water
channels, the optical fiber channels, tendons, and so forth. The
vertebra could also include attachment sites for the tendons,
including the sleeve and inner cable of the Bowden cable
embodiments. Further, the outer edge of the control ring could
include channels for holding tendons that control more distal
segments. These channels could provide methods of arranging and
organizing such tendons. For example, in another variation, the
tendons controlling more distal segments are helically wound around
the outer surface of more proximal segments as the tendons project
proximally to the controller. Such helical winding could prevent
unintended tension on tendons controlling more distal segments when
proximal segments are bent. Alternatively, the tendons can include
excess "slack." Such excess slack could also help prevent proximal
segments from being constrained by bypassing tendons controlling
more distal segments.
[0020] Another variation of the control ring omits hinged
vertebrae, but instead relies on a flexible backbone throughout the
endoscope, to which control rings (also called support rings) are
attached at intervals. In one variation using a Bowden cable, the
tendon inner cables are attached at the most distal control ring in
a segment, and the tendon sleeve is attached at the most proximal
control ring. The control rings may have spaces allowing components
to pass through the segments, and most of the same features
described for the vertebra-type control rings.
[0021] A proximal handle may be attached to the proximal end of the
endoscope and may include imaging devices connected to the
fiberoptic imaging bundle for direct viewing and/or for connection
to a video camera or a recording device. The handle may be
connected to other devices, e.g., illumination sources and one or
several luer lock fittings for connection to various instrument
channels. The handle may also be connected to a steering control
mechanism for controlling the steerable distal portion. The handle
may optionally have the steering controller integrated directly
into the handle, e.g., in the form of a joystick, conventional disk
controller using dials or wheels, etc.
[0022] As the endoscope is advanced or withdrawn axially, a depth
referencing device, or axial transducer, may be used to measure the
relative current depth (axial position) of the endoscope. This
axial motion transducer can be made in many possible
configurations, such as devices that work by contacting, signaling,
or communicating to the endoscope. For example, as the body of the
endoscope slides through the transducer, it produces a signal
indicating the axial position of the endoscope body with respect to
the fixed point of reference. This measure corresponds to the depth
of the endoscope within the body cavity. The transducer may also
use non-contact methods for measuring the axial position of the
endoscope body, such as optical, capacitive, resistive, radio
frequency or magnetic detection.
[0023] Another variation of the endoscope is fully articulatable
over its entire length. Thus, for example, if the endoscope is a
standard length of 180 cm, a total of 18 segments (including the
steerable distal end), each 10 cm long, could be combined to create
a fully articulating, controllable endoscope. In an alternative
variation, a passive region proximal to the automatically
controlled proximal region could be made of a flexible tubing
member that can conform to an infinite variety of shapes.
[0024] In this variation, the entire assembly, i.e. segments,
tendons, etc., may be encased in a sheath or covering of a
biocompatible material, e.g. a polymer, that is also preferably
lubricious to allow for minimal friction resistance during
endoscope insertion and advancement into a patient. Because the
endoscope is used medically, it may be desirable that this covering
being removable, replaceable and/or sterilizable.
[0025] Similarly, it is desirable that the endoscope be easily
disconnected from the controller. The tendons projecting proximally
from the segments of the endoscope are collectable in a umbilicus
that has an interface which couples with a controller unit
containing the actuators, e.g., motors, that apply force to the
tendons. This interface may be a quick-disconnect mechanism between
the tendons and the controller. One variation of the
quick-disconnect mechanism is a "nail head" positionable in a slot
design in which the terminus of each tendon cable is configured
into, e.g., a flattened protrusion. An array of such tendons at the
end of the umbilicus mates with an interface on the controller. The
flattened tendon ends may be fitted into corresponding slots
defined in the controller housing. The corresponding fit enables
the tendon ends to be removably secured within their respective
slots and thereby allows the actuators to apply force to specific
tendons. Further, the controller can determine the shape of a
segment based on the tension being applied by its controlling
tendons. The controller can also be adapted to determine segment
configuration based upon the position of the cable relative to the
cable housing. Moreover, the controller may be further adapted to
sense the amount of rotation or linear movement of the controlling
tendons and can determine segment configuration based upon this
data.
[0026] Many alternatives of the quick-disconnect mechanism are
contemplated by this invention. Another variation has a mating
connector with pins that couple to dimpled receptors; motions of
the pins against the receptor are translated into motion of the
tendons, e.g. using levers, gears or gear racks, or threaded
couplings.
[0027] A typical endoscope has a diameter less than 20 mm, although
various industrial applications may utilize endoscopes having a
diameter greater than 20 mm. Likewise, one variation of this
invention also has a radial dimension of less than 20 mm. In
another variation of the invention, the radius of more distal
segments decreases in a telescope-like fashion. This allows the
steerable distal portion to have a much smaller radius, e.g., 12.5
mm, than the more proximal segments. In this variation, the larger
radius of more proximal segments provides increased space for
tendons from distal segments.
[0028] Another alternative variation of this invention uses fewer
segments by having segments of different lengths. Thus, more
distally located segments can be made shorter, e.g., the most
distal segment can have a length of 6 cm, and more proximally
located segments increasingly longer, e.g., up to 20 cm length for
the most proximal segment. This variation modifies the way selected
curves are propagated by the advancement of the endoscope,
resulting in an "averaging" or smoothing of the curve as it
propagates down the scope. In this variation, a special algorithm
can be used to coordinate the automation of the differently sized
segments.
[0029] One method of propagating the selected turns of the
steerable tip along the body of the endoscope involves having the
endoscope follow the pathway selected by the user as it is advanced
or withdrawn from the body. This method begins by inserting the
distal end of the endoscope 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 controller registers the motion and
controls the proximal portion of the endoscope to assume the curve
selected by the user when the steerable distal tip was in
approximately the same position within the body. Similarly, when
the endoscope is withdrawn proximally, the selected curves are
propagated distally along the endoscope body, either automatically
or passively.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] FIG. 1 shows a representation of a conventional endoscope in
use.
[0031] FIG. 2 shows a variation of the tendon driven endoscope of
the present invention
[0032] FIG. 3A shows the range of motion of a controllable segment
of the present invention actuated by three tendons.
[0033] FIGS. 3B to 3F show the use of three tendons to actuate a
controllable segment used in the endoscope of the present
invention.
[0034] FIGS. 4A and 4B show the use of two tendons to actuate a
controllable segment in the endoscope of the present invention.
[0035] FIGS. 4C and 4D show the use of four tendons to actuate a
controllable segment in the endoscope of the present invention.
[0036] FIG. 5 shows a partial schematic representation of a single
tendon bending a segment.
[0037] FIGS. 6A and 6B show an end view and a side view,
respectively, of a vertebra-type control ring which may be used to
form the controllable segments of the endoscope of the present
invention.
[0038] FIG. 6C shows a side view of interconnected vertebra-type
control rings used to form the controllable segments of the
endoscope of the present invention.
[0039] FIG. 6D and 6E show a side view and a perspective view,
respectively, of another embodiment of a vertebra-type control
ring.
[0040] FIG. 7A shows a perspective view of an endoscope device
variation with the outer layers removed to reveal the control rings
and backbone.
[0041] FIG. 7B shows an end view of a variation of the control ring
for an endoscope of the present invention.
[0042] FIGS. 8A to 8C illustrate advancing the tendon driven
endoscope of the present invention through a tortuous path.
[0043] FIG. 9 shows a variation of the tendon driven endoscope of
the present invention that has segments of differing diameters.
[0044] FIG. 10 shows a variation of the tendon-driven endoscope of
the present invention that has segments of different length.
[0045] FIG. 11A shows a variation of a quick-release mechanism for
attaching and detaching the tendon driven endoscope from the
actuators that relies on pins to actuate the tendons.
[0046] FIG. 11B shows a second variation of a quick-release
mechanism for attaching and detaching the tendon driven endoscope
from the actuators that relies on a nail-head configuration to
actuate the tendons.
[0047] FIGS. 12A to 12E illustrate a representative example of
advancing an endoscope through a patient's colon using a tendon
driven endoscope of the present invention.
[0048] FIG. 12F illustrates a variation on withdrawing the tendon
driven endoscope of the present invention.
[0049] FIG. 13 shows a flow diagram for initializing or
re-initializing an endoscopic device during a procedure.
DETAILED DESCRIPTION OF THE INVENTION
[0050] FIG. 1 shows a prior art colonoscope 10 being employed for a
colonoscopic examination of a patient's colon C. The colonoscope 10
has a proximal handle 16 and an elongate body 12 with a steerable
distal portion 14. The body 12 of the colonoscope 10 has been
lubricated and inserted into the colon C via the patient's anus A.
Utilizing the steerable distal portion 14 for guidance, the body 12
of the colonoscope 10 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 10 from the proximal end to advance it
through the turns of the colon C. After the steerable distal
portion 14 has passed, the walls of the colon C maintains the curve
in the flexible body 12 of the colonoscope 10 as it is advanced.
Friction develops along the body 12 of the colonoscope 10 as it is
inserted, particularly at each turn in the colon C. Because of the
friction, when the user attempts to advance the colonoscope 10, the
body 12' tends to move outward at each curve, pushing against the
wall of the colon C, which exacerbates the problem by increasing
the friction and making it more difficult to advance the
colonoscope 10. On the other hand, when the colonoscope 10 is
withdrawn, the body 12'' tends to move inward at each curve taking
up the slack that developed when the colonoscope 10 was advanced.
When the patient's colon C is extremely tortuous, the distal end of
the body 12 becomes unresponsive to the user's manipulations, and
eventually it may become impossible to advance the colonoscope 10
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.
[0051] FIG. 2 shows a variation of the tendon driven endoscope 20
of the present invention. The endoscope 20 has an elongate body 21
with a manually or selectively steerable distal portion 24, an
automatically controlled portion 28, and a flexible and passively
manipulated proximal portion 22, which may be optionally omitted
from the device. The steerable distal portion 24 can be articulated
by hand or with mechanical assistance from actuators. The
automatically controlled portion 28 is segmented, and each segment
is capable of bending through a full range of steerable motion. The
distal portion 24 is also a controllable segment.
[0052] The selectively steerable distal portion 24 can be
selectively steered or bent up to, e.g., a full 18020 bend in any
direction 26, as shown. A fiberoptic imaging bundle 40 and one or
more illumination fibers 42 may extend through the body 21 from the
proximal portion 22 to the distal portion 24. Alternatively, the
endoscope 20 may be configured as a video endoscope with a
miniaturized video camera, such as a CCD or CMOS camera, positioned
at the distal portion 24 of the endoscope body 21. 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 and/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. LEDs or other light
sources could also be used for illumination at the distal tip of
the endoscope.
[0053] The body 21 of the endoscope 20 may also include one or more
access lumens 38 that may optionally be used for illumination
fibers for providing a light source, insufflation or irrigation,
air and water channels, and vacuum channels. Generally, the body 21
of the endoscope 20 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 21 of the endoscope 20 may range typically
from 135 to 185 cm in length and about 13-19 mm in diameter. The
endoscope 20 can be made in a variety of other sizes and
configurations for other medical and industrial applications.
[0054] The controllable portion 28 is composed of at least one
segment 30, and preferably several segments 30, which are
controllable via a computer and/or electronic controller
(controller) 45 located at a distance from the endoscope 20. Each
of the segments 30 has tendons mechanically connected to actuators
to allow for the controlled motion of the segments 30 in space. The
actuators driving the tendons may include a variety of different
types of mechanisms capable of applying a force to a tendon, e.g.,
electromechanical motors, pneumatic and hydraulic cylinders,
pneumatic and hydraulic motors, solenoids, shape memory alloy
wires, electronic rotary actuators or other devices or methods as
known in the art. If shape memory alloy wires are used, they are
preferably configured into several wire bundles attached at a
proximal end of each of the tendons within the controller. Segment
articulation may be accomplished by applying energy, e.g.,
electrical current, heat, etc., to each of the bundles to actuate a
linear motion in the wire bundles which in turn actuate the tendon
movement. The linear translation of the actuators within the
controller may be configured to move over a relatively short
distance, e.g., within a few inches or less such as .+-.1 inch, to
accomplish effective articulation depending upon the desired degree
of segment movement and articulation.
[0055] It is preferable that the length of the insertable portion
of the endoscope comprises controllable segments 30, although a
passive proximal portion 22 can also be used. This proximal portion
22 is preferably a flexible tubing member that may conform to an
infinite variety of shapes, and may be made from a variety of
materials such as thermoset and thermoplastic polymers which are
used for fabricating the tubing of conventional endoscopes.
[0056] Each segment 30 preferably defines at least one lumen
running throughout 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. A polymeric covering, or sheath, 39 may also extend over
the body of the endoscope 21 including the controllable portion 28
and steerable distal portion 24. This sheath 39 can preferably
provide a smooth transition between the controllable segments 30,
the steerable distal portion 24, and the flexible tubing of
proximal portion 22.
[0057] A handle 32 may be attached to the proximal end of the
endoscope. The handle 32 may include an ocular connected to the
fiberoptic imaging bundle 42 for direct viewing. The handle 32 may
otherwise have a connector 54 for connection to a video monitor,
camera, e.g., a CCD or CMOS camera, or a recording device 52. The
handle 32 may be connected to an illumination source 43 by an
illumination cable 44 that is connected to or continuous with the
illumination fibers 42. Alternatively, some or all of these
connections could be made at the controller 45. Luer lock fittings
34 may be located on the handle 32 and connected to the various
instrument channels.
[0058] The handle 32 may be connected to a motion controller 45 by
way of a controller cable 46. A steering controller 47 may be
connected to the motion controller 45 by way of a second cable 48
or it may optionally be connected directly to the handle 32.
Alternatively, the handle may have the steering control mechanism
integrated directly into the handle, e.g., in the form of a
joystick, conventional disk controllers such as dials, pulleys or
wheels, etc. The steering controller 47 allows the user to
selectively steer or bend the selectively steerable distal portion
24 of the body 21 in the desired direction 26. The steering
controller 47 may be a joystick controller as shown, or other
steering control mechanism, e.g., dual dials or rotary knobs as in
conventional endoscopes, track balls, touchpads, mouse, or sensory
gloves. The motion controller 45 controls the movement of the
segmented automatically controlled proximal portion 28 of the body
21. This controller 45 may be implemented using a motion control
program running on a microcomputer or using an application-specific
motion controller. Alternatively, the controller 45 may be
implemented using, e.g., a neural network controller.
[0059] The actuators applying force to the tendons may be included
in the motion controller unit 45, as shown, or may be located
separately and connected by a control cable. The tendons
controlling the steerable distal portion 24 and the controllable
segments 30 extend down the length of the endoscope body 21 and
connect to the actuators. FIG. 2 shows a variation in which the
tendons pass through the handle 32 and connect directly to the
motion controller 45 via a quick-release connector 60. In this
variation, the tendons are part of the control cable 46, although
they could independently connect to the actuators, so long as the
actuators are in communication with the controller 45.
[0060] An axial motion transducer (also called a depth referencing
device or datum) 49 may be provided for measuring the axial motion,
i.e., the depth change, of the endoscope body 21 as it is advanced
and withdrawn. The depth referencing device 49 can be made in many
possible configurations. For example, the axial motion transducer
49 in FIG. 2 is configured as a ring 49 that may surround the body
21 of the endoscope 20. The axial motion transducer 49 is
preferably attached to a fixed point of reference, such as the
surgical table or the insertion point for the endoscope 20 on the
patient's body. As the body 21 of the endoscope 20 slides through
the axial motion transducer 49, it indicates the axial position of
the endoscope body 21 with respect to the fixed point of reference
and sends a signal to the electronic controller 45 by telemetry or
by a cable. The axial motion transducer 49 may use optical,
electronic, magnetic, radio frequency or mechanical methods to
measure the axial position of the endoscope body 21.
[0061] When the endoscope body 21 is advanced or withdrawn, the
axial motion transducer 49 detects the change in position and
signals the motion controller 45. The controller can use this
information to propagate the selected curves proximally or distally
along the controllable portion 28 of the endoscope body 21 to keep
the endoscope actively following the pathway selected by the user
steering the distal portion 24. The axial motion transducer 49 also
allows for the incrementing of a current depth within the colon C
by the measured change in depth. This allows the endoscope body 21
to be guided through tortuous curves without putting unnecessary
force on the wall of the colon C.
[0062] A more detailed description on the construction and
operation of a variation of the segments may be found in U.S.
patent application Ser. No. 09/969,927 entitled "Steerable
Segmented Endoscope and Method of Insertion" filed Oct. 2, 2001,
which is incorporated by reference in its entirety.
[0063] FIG. 3A shows an example of the resulting segment
articulation which may be possible through the use of two or three
tendons to articulate the controllable segments, including the
steerable distal section. FIG. 3A shows one example of a possible
range of motion of a controllable segment of the present invention
actuated, in this example, by three tendons. A segment in the
relaxed, upright position 301 can be bent in virtually any
direction relative to the x-y plane. The figure, as an illustrative
example, shows a segment 302 that has been bent down and at an
angle relative to its original position 301. The angles .alpha. and
.beta. describe the bend assumed by the segment. Angle .beta. gives
the angle in the x-y plane, while .alpha. is the angle describing
the motion in the x-z plane. In one variation, the controllable
segments of the endoscope can bend through all 360 degrees in the
.beta. angle and up to 90 degrees in the .alpha. angle. An angle
.alpha. greater than 90 degrees would result in looping of the
endoscope. In FIG. 3A, the segment is shown bent approximately 45
degrees along angle .alpha.. The freedom of movement of a segment
is, in part, determined by the articulation method, the size of the
segment, the materials from which it is constructed, and the manner
in which it is constructed, among others. Some of these factors are
discussed herein.
[0064] The steerable distal portion, as well as the endoscope and
the controllable segments are bendable but preferably not
compressible or expansible. Thus, in FIG. 3A, the centerline 304 of
the relaxed segment 301 is approximately the same length as the
centerline 306 of the segment after bending 302.
[0065] FIGS. 3B to 3F show the use of three tendons to actuate a
controllable segment used in an endoscope of the present invention.
The tendons shown in this example are all Bowden type cables 310
that have an internal cable 312 coaxially surrounded by a housing
or sleeve 314 in which the cable is free to move. Bowden cables can
be used to apply either tensile or compressive forces, i.e., they
may be pushed or pulled, to articulate the endoscope and can be
actuated remotely to deliver forces as desired at locations along
the endoscope. Force from a tendon is exerted across or through the
segment by attaching the tendon cable at the distal end of the
segment 320 and the tendon housing 314 at the proximal end of the
segment 322. FIG. 3B shows a view of the top of the segment with
three attachment sites for the tendon cables indicated 320.
[0066] In one variation, three tendons are used to actuate each
segment, including the steerable distal portion, although four or
more tendons could be used. Three tendons can reliably articulate a
segment in any direction without having to rotate the segment or
endoscope about its longitudinal axis. The three cable tendons 312
are preferably attached at the distal end of the segment 320 close
to the segment's edge, spaced equally apart. In FIG. 3B, tendons
are attached at the two o'clock, six o'clock and 10 o'clock
positions. It is desirable to use fewer tendons, because of space
concerns, since the tendons controlling each segment project
proximally to the actuators. Thus, two tendons could be used to
control a segment. It may also be desirable to include one or more
biasing element, e.g., a spring, to assist in articulating a
segment in three dimensions. In another variation, two tendons may
be used to articulate a segment in three dimensional space by
controlling motion in two directions while rotating the segment
about its longitudinal axis.
[0067] FIG. 3C shows a relaxed segment with three tendons attached.
The tendon sleeves 314 are shown attached to the proximal end of
the segment 322 directly below the corresponding cable attachment
sites. FIGS. 3D to 3F show this segment bent by each of the
controlling tendons 310 separately.
[0068] As shown in FIG. 3D, applying tension by pulling on the
first tendon 330 results in a bending in the direction of the first
tendon 330. That is, looking down on the top of the unbent segment
(as in FIG. 3B), if the first tendon is attached at the six o'clock
position, then pulling on just this tendon results in bending the
segment towards the six o'clock position. Likewise, in FIG. 3E,
putting tension only on a second tendon 332 attached at the two
o'clock position results in bending the segment towards the two
o'clock direction. Finally, pulling on the tendon in the ten
o'clock position 334 bends the segment towards the ten o'clock
direction. In all cases, the bending is continuous; the greater the
tension applied, the further the bending (the .alpha. angle, in the
x-z plane of FIG. 3A). A segment can be bent in any direction by
pulling on individual tendons or a combination of two tendons.
Thus, to bend the segment in the twelve o'clock direction, both the
second 332 and the third 334 tendon could be pulled with equal
force. Alternatively, first tendon 330 in the six o'clock position
may be pushed either alone or in combination with second 332 and
third tendons 334 being pulled to result in the same
configuration.
[0069] FIGS. 4A and 4B show a variation in which a segment is
articulated by two tendons and one biasing element. FIG. 4A shows a
planar top view of the segment. The attachment sites for the
biasing element 340 and the two tendons 320 are spaced around the
perimeter of the distal end of the segment as shown. The tendons
320 may be attached at the two o'clock and ten o'clock positions,
looking down on the top of the section, and the biasing element 340
is attached at the six o'clock position. FIG. 4B shows a
perspective view of the segment in the unbent configuration. In
this variation, the biasing element is configured to apply tension
to the side of the segment such that it will bend towards the six
o'clock position. The biasing element can be any element that can
apply compressive or tensile forces across the segment, e.g. a
spring, elastic element, a piston, etc. The segment is held in the
neutral or unbent position shown in FIG. 4B by applying tension
from both tendons 312. Controlling the amount of tension applied by
the tendons results in bending of the segment in three dimensional
space. More than one biasing element could also be used with two or
more tendons. For example, a biasing element could be located
opposite each tendon.
[0070] Alternatively, if the tendon is a push-pull cable, and each
tendon can apply compression as well as tension, then two tendons
can control the motion of segment without any biasing element at
all.
[0071] More than three tendons can also be used to control the
bending of a segment. FIG. 4C shows a top planar view of a segment
that is controlled by four tendons attached in the eleven o'clock,
two o'clock, five o'clock and eight o'clock positions. As with the
three-tendon embodiment, tension applied on one or a combination of
the tendons results in shortening the side of the segment. Thus, if
tension is applied only on the tendon attached distally at the
eleven o'clock position 355, the corresponding side of the tendon
will shorten, and the segment will bend in the eleven o'clock
direction.
[0072] In all these variations, the circumferential locations of
the tendons and/or biasing elements are illustrative and are not
intended to be limited to the examples described herein. Rather,
they may be varied according to the desired effects as understood
by one of skill in the art.
[0073] FIG. 5 shows a partial schematic representation of a single
tendon bending a segment. For clarity, the other parts of a
complete endoscope, including other tendons and segments, have been
omitted from FIG. 5. Tension applied to a tendon cable is
transferred across the entire segment, resulting in bending. By
using a Bowden cable 310 whose sleeve 314 is attached to the base
322 of the segment and also fixed at the proximal actuator end 403,
only the intended segment 401 is bent by applying tension to the
tendon 312, and more proximal segments are unaffected. The tendon
is placed in tension by the actuator 410, which is shown, in this
variation, as a motor pulling on the tendon cable 312.
[0074] Linked control rings may provide the flexible structure
needed to construct the steerable distal portion and the
controllable segments. Two examples of the types of control rings
that may be utilized are shown. The first is shown in FIG. 6A which
shows a vertebra-type control ring that forms the controllable
segments of the present invention. FIG. 6A shows an end view of a
single vertebra. Each ring-shaped vertebra 501 can define a central
channel or aperture 504 or apertures that can collectively form the
internal lumen of the device as previously described. The vertebrae
may have two pairs of hinges; the first pair 506 projecting
perpendicularly from a first face of the vertebra and a second pair
508, located 90 degrees around the circumference from the first
pair, projecting perpendicularly away from the face of the vertebra
on a second face of the vertebra opposite to the first face. The
hinges shown in FIGS. 6A and 6B are tab-shaped, however other
shapes may also be used.
[0075] The vertebra control ring in FIG. 6A is shown with three
holes 510 through the edge of the vertebra that may act, e.g., as
attachment sites for the tendon cable 312 if the vertebra is the
most distal vertebra in a segment, or as a throughway for a tendon
cable that can actuate the segment in which the vertebra is used.
These holes 510 can also be used to attach the sleeve of the
Bowden-type tendon cable 314 when the vertebra is the most proximal
control disk in a segment. Alternatively, rather than a hole 510,
the attachment sites could be a recess or other specialized shape.
Although FIG. 6A shows three holes 510, the number of holes may
depend upon the number of tendons used to control the segment to
which the vertebra belongs. Since the holes 510 may be used as
attachment sites for the tendons, there are as many holes as there
are tendons controlling the segment.
[0076] The outer edge of the vertebra in FIG. 6A may be scalloped
to provide spaces 512 for tendon housings of tendons that control
more distal segments and bypass the vertebra. These tendon bypass
spaces preferably conform to the outer diameter of the tendons
used. The number of tendon bypass spaces 512 may vary depending on
the number of tendons. Also, the orientation of the tendon bypass
spaces may be varied if it is desirable to vary the way in which
the bypassing tendons are wound around the endoscope. For example,
the spaces 512' in FIG. 6C are oriented at an angle relative to the
longitudinal axis of the vertebra, allowing the tendons to wind
around the body of the endoscope as they project proximally.
Furthermore, the tendon bypass spaces could be lubricated or
composed of a lubricious material in order to facilitate free
movement of the bypassing tendons across the segment, and prevent
interference between the bending of the segment and the bypassing
tendons.
[0077] FIGS. 6B and 6C show side views of the same vertebra as FIG.
6A. The two pairs of hinge joints 508, 506 are shown. Hinge joints
508, 506 are preferably located 90 degrees apart and extend axially
so that the hinge joints can pivotally mate with hinge joints from
adjacent vertebrae. This mating 520 with adjacent vertebrae is more
clearly seen in FIG. 6C. These hinges can be joined, pinned, or
connected through the holes 525 as shown 522. Alternatively, hinges
may also be made from materials utilizing, e.g., thermoplastics,
shape memory alloys, etc. Once hinged, each vertebra can rotate
relative to an adjoining vertebra in one axis. However, because
vertebrae are hinged to each other in directions alternating by 90
degrees, an assembly of multiple vertebrae is able to move in
virtually any direction. The greater the number of vertebrae joined
in this manner, the greater the range of motion. In one embodiment,
two to ten vertebrae are used to comprise one segment, achieving a
length of around 4 cm to 10 cm per segment. The dimensions of both
the vertebrae and the hinge joints can be varied, e.g., longer
hinge joints will have a greater bending radius when joined to
another vertebra. Furthermore, the number of vertebrae per segment
can vary, e.g. more than ten vertebrae could be used.
[0078] FIGS. 6D and 6E show another variation of a vertebra in
sectional and perspective views, respectively. In FIGS. 6D and 6E,
the tendons that bypass the segment may be contained within the
body of the vertebra in a tendon bypassing space 550 rather than
along the outer edge of the vertebra as shown in FIG. 6A. The
vertebra of FIGS. 6D and 6E show four tendon bypassing spaces 550,
and each space can hold approximately fifteen bypassing tendon
sleeves. The number, shape and sizes of the tendon bypassing spaces
can be varied. For example, a vertebra could have two tendon
bypassing spaces that could hold more than thirty-five tendon
sleeves. Moreover, the tendon bypassing space could also be located
on the inside of the central aperture or lumen of the vertebra
504.
[0079] Although FIG. 6D shows tendon sleeves holding only a single
tendon cable 560, more than one tendon cable could be contained in
a tendon housing or sleeve. For example, if three tendons
articulate a segment, all three tendons could be contained in a
single tendon housing. Such a combined tendon housing could further
utilize lubrication to accommodate independent movement by
individual tendon cables and/or could be divided into compartments
that isolate the tendons within the housing.
[0080] FIG. 6E also shows a perspective view of the hinge joints
506, 508 that can pivotally mate with pairs of hinge joints from
adjacent vertebrae. Although FIGS. 6A and 6B shows two pairs of
hinge joints projecting axially, a single hinge joint on each face
of the vertebra could also be used. Moreover, as long as the hinge
joints can pivotally mate with adjacent vertebrae, the hinge joints
can be located at different radial locations from the center of the
vertebra. For example, the pairs of hinge joints shown in FIGS. 6A
to 6C are located closer to the center of the vertebra than the
hinge joints in FIGS. 6D and 6E.
[0081] FIG. 7 shows a second variation of control ring. The
variation shown in the figure utilizes a flexible backbone 601
preferably made of a material that is relatively non-compressible
and non-extensible, to which control rings 602 are attached at
intervals. This structure allows bending in a continuous curve in
any desired direction. FIG. 7A shows a side view of one
controllable segment of this variation with the outer layers
removed to show the control rings and backbone. Multiple control
rings 602 may be attached to the flexible backbone at regular
intervals. Fewer or more control rings could be used to comprise a
single segment depending upon the desired degree of articulation.
The tendon cable 312 attaches to the most distal control ring of
the segment 604. As with the vertebra-type variation, this central
backbone embodiment is shown actuated by three tendons 310 attached
at sites equally spaced around the edge of the most distal control
ring of the segment 604. The tendon cables controlling the segment
312 pass through spaces or holes 610 defined in the control rings
602 through which they are free to move. These holes 610 could be
lubricated, lined with a lubricious material or the control rings
602 may be composed of some lubricious material to facilitate cable
motion through the holes 610. The tendon sleeve preferably attaches
at a location 614 to the most proximal control ring in the segment
612. When a tendon 312 is placed under tension, this force is
distributed along the entire segment. Because the inner tendon
cable 312 is freely slidable within the tendon sleeve 314, and the
tendon sleeve is fixed at both ends of the tendon 614, pulling on
the tendon cable causes bending only in the selected segment.
[0082] FIG. 7A also shows the first control ring of a more proximal
segment 604'. The tendons controlling the more distal segment may
pass over the outside of the more proximal segments as they project
proximally to the actuators. The outer edge of the control rings
for the flexible backbone embodiment are shown with channels or
tendon bypassing spaces 616 for bypassing tendons, as seen in FIG.
7B. As with the vertebra-type control rings, these tendon bypassing
spaces could also be located within the control ring, for example,
in an enclosed tendon bypassing space.
[0083] FIG. 7B shows an end view of control ring 602 which may be
used with the flexible backbone embodiment of the endoscope. The
center of the control ring contains a channel through which the
flexible backbone 601 can be attached. A number of additional
channels through the control ring 618 are also shown. These
channels can be aligned with channels in neighboring control rings
to form an internal lumen or channel for a fiber optic imaging
bundle, illumination fibers, etc. as discussed above. Moreover,
adjacent control rings may be spaced adjacently to one another at
uniform or various distances depending upon the desired degree of
bending or control. FIG. 7B shows three equally spaced holes 610
through which the tendon cable can pass; these holes 610 could also
be used as attachment sites for the tendon cable, e.g., when the
control ring is the most distal control ring in the segment 604, or
for the tendon cable sleeve, e.g. when the control ring is the most
proximal control ring in the segment 612. These holes 610 could be
shaped specifically to receive either the tendon end or the tendon
sleeve. Control rings of other designs could be used for different
regions of the segment, or for different segments.
[0084] FIGS. 8A to 8C illustrate a variation of the tendon driven
endoscope navigating a tortuous path. The path 701 is shown in FIG.
8A. This pathway may represent a portion of colon, for example. In
FIG. 8A, the distal tip of the device 704 approaches the designated
bend. FIG. 8B shows the distal tip being steered 705 to assume the
appropriate curve. This steering could be performed manually by the
user, e.g. a doctor, or automatically using an automatic detection
method that could determine the proximity of the walls of the
pathway. As described, the bending of the steerable tip is
performed by placing tension on the tendon, or combination of
tendons that results in the appropriate bending.
[0085] The device is then advanced again in FIG. 8C; as it is
advanced, the selected curve is propagated down the proximal length
of the endoscope, so that the bend of the endoscope remains in
relatively the same position with respect to the pathway 701. This
prevents excessive contact with the walls, and allows the endoscope
to move more easily along the tortuous pathway 701. The endoscope
is in continuous communication with the motion controller, and the
motion controller can monitor the location of the endoscope within
the pathway, e.g., depth of insertion, as well as the selected
bends or curves that define the pathway of the endoscope. Depth can
be determined by, e.g., the axial motion transducer 49 previously
described, or by more direct measurement techniques. Likewise, the
shape of each segment could be determined by the tension applied to
the tendons, or by direct measurement, such as direct measurement
of displacement of the tendon cables. The motion controller can
propagate the selected shape of a segment at a specified location,
or depth, within the body, e.g., by setting the lengths of the
sides of more proximal segments equal to the corresponding lengths
of the sides of more distal segments as the device is moved
distally. The controller can also use this information to
automatically steer the body of the endoscope, or for other
purposes, e.g. creating a virtual map of the endoscope pathway for
analytic use.
[0086] In addition to measuring tendon displacement, the motion
controller can also adjust for tendon stretch or compression. For
example, the motion controller can control the "slack" in the
tendons, particularly in tendons that are not actively under
tension or compression. Allowing slack in inactive tendons reduces
the amount of force that is required to articulate more proximal
segments. In one variation, the umbilicus at the distal end of the
endoscope may contain space to allow slack in individual
tendons.
[0087] The bending and advancing process can be done in a stepwise
or continuous manner. If stepwise, e.g., as the tendon is advanced
by a segment length, the next proximal segment 706 is bent to the
same shape as the previous segment or distal steerable portion. A
more continuous process could also result by bending the segment
incrementally as the tendon is advanced. This could be accomplished
by the computer control, for example when the segments are smaller
than the navigated curve.
[0088] Controllable segments, including the steerable distal
portion, can be selected to have different dimensions, e.g.,
different diameters or lengths, even within the same endoscope.
Segments of different dimensions may be desirable because of
considerations of space, flexibility and method of bending. For
example, the more segments in an endoscope, the further it can be
steered within a body cavity; however, more segments require more
tendons to control the segments. FIGS. 9 and 10 illustrate two
variations on tendon driven endoscopes.
[0089] FIG. 9 shows a tendon driven endoscope variation that has
segments 800 of differing diameters. More distal segments may have
a smaller diameter 803 than more proximal segments, e.g., 802, 801.
The diameter of a typical endoscope could decrease from, e.g., 20
mm, down to, e.g., 12.5 mm. The endoscope shown in FIG. 9 appears
telescoped, as the diameter decreases distally in a stepwise
manner. This design would be responsive, e.g., to internal body
structures that become increasingly narrow. This design would also
help accommodate bypassing tendons from more distal segments as
they proceed towards the proximal actuators because of the larger
diameter of the more proximal segments. FIG. 9 shows four
differently sized segments; however, virtually any number of
differently sized segments could be used. Moreover, although the
segments appear stepped in this variation, the outer surface may be
gently tapered to present a smooth outer surface decreasing in
diameter towards the distal end.
[0090] FIG. 10 shows another variation of the tendon driven
endoscope that has segments of different lengths. Using segments of
different lengths may require fewer overall segments 900 to
construct an equivalent length of articulatable endoscope. As shown
in FIG. 10, more proximal segments 901 are increasingly longer than
more distal, e.g., 902, 903, segments. For example, segment length
could be decreased from 20 cm at a proximal segment down to 6 cm at
a distal most segment. The lengths may be decreased incrementally
segment to segment by a constant factor; alternatively, lengths may
be decreased geometrically, exponentially, or arbitrarily depending
upon the desired articulation. In practice this results in an
"averaging" of curves by more distal segments as bends and turns
are propagated proximally. In order to accomplish this, the motion
controller may be configured to accommodate the differently sized
segments accordingly. Alternatively, endoscopes could be comprised
of a combination of segments of different length and thickness,
depending upon the application.
[0091] The tendons that articulate the segments are in mechanical
communication with the actuators. However, it may be desirable to
have the insertable distal portion of the endoscope be removable
from the actuators and controller, e.g., for cleaning or
disinfecting. A quick-release mechanism between the proximal end of
the endoscope and the actuators is an efficient way to achieve an
endoscope that is easily removable, replaceable or interchangeable.
For example, the proximal ends of the tendons can be organized to
allow predictable attachment to corresponding actuators. The
tendons may be organized into a bundle, array, or rack. This
organization could also provide other advantages to the endoscope,
such as allowing active or passive control of the tendon slack.
Furthermore, the proximal ends of each tendon can be modified to
allow attachment and manipulation, e.g., the ends of the tendons
may be held in a specially configured sheath or casing.
[0092] FIGS. 11A and 11B show two variations on quick-release
mechanisms for attaching and detaching the tendon driven endoscope
from the actuators. FIG. 11A shows one variation of this
quick-release mechanism. The proximal end of the tendons is bundled
in an umbilicus 950, and the individual tendons terminate in
dimpled connectors 962 that are held in an organized array in a
connector interface 952. The connector interface 952 mates to a
complementary receiving interface 956 on the structure that houses
the actuators 970, e.g. as part of the controller box. The
actuators may project "pins" 960 which can mate with the dimpled
connectors and convey force from the actuators to the tendons.
Thus, for example, an actuator may cause a pin 960 to apply
pressure to a corresponding dimpled receiver 962. The dimpled
receiver translates the pushing of the pin into a tensile or
compressive force applied to the affiliated tendon. This could be
achieved using levers to reverse the direction of the force, for
example. Since every pin preferably mates to a corresponding
receiver, it is desirable to maintain the register of the
connectors from the endoscope and the actuators. An orientation
notch 954 on the connector that fits into a receiving orientation
mate 958 on the actuator could be used to align both interfaces.
Alternatively, the arrangement of the pins and receptacles could be
orientation specific.
[0093] This feature is not limited to pins and receptacles, since
virtually any convenient mechanism for transferring force from the
actuator to the tendons would work. FIG. 11B shows a second
variation of a quick-release mechanism for attaching and detaching
the tendon driven endoscope from the actuators that relies on a
nail-head configuration to actuate the tendons. The tendons
preferably terminate in a flattened out protrusion resembling a
nail-head 972. The array of nail-heads project from the connector
interface 952 at the end of the umbilicus holding the endoscope
tendons 950, and can mate with slotted holes 974 on the interface
956 of the actuator mechanism 970. Thus the slotted holes 974 of
the actuators can be individually retracted by the actuators to
apply tension to individual tendons. The quick-release mechanism
could also be designed allow users to use different tendon driven
endoscopes, even of different configurations, from the same
actuator and/or controller unit.
[0094] FIGS. 12A to 12F show the endoscope 100 of the present
invention being employed for a colonoscopic examination of a
patient's colon. In FIG. 12A, 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 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. The control signals from the steering
control to the selectively steerable distal portion 104 are
monitored by the electronic motion controller 49. 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
controller 45 as a reference. This step can be performed in a
manual mode, in which the user gives a command to the controller 45
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 controller 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.
[0095] In one variation, the curve is entered into the controller's
memory by recording the change in lengths of the sides of the
steerable distal portion after the distal portion has been
articulated into the selected shape. In variations where the
tendons are Bowden-type cables, the change in the length of the
distal portion may be determined from the distance traveled by the
tendon cable after steering the distal portion from the neutral,
unbent, position. This distance traveled by the tendon cable may be
determined relative to the cable housing or to another point
located within the controller. Likewise, the change in lengths of
the sides of any controllable segment can be determined in the same
way.
[0096] As the endoscope is advanced distally, a curve is propagated
proximally down the endoscope by setting the lengths of the sides
of the more proximal segment equal to the lengths of the same sides
of the steerable distal tip when the distal tip was in
approximately the same axial position. In one variation the lengths
of the sides are equal to the lengths of the non-extensible,
non-compressible tendons. The tendons in the more proximal segment
are tensioned or compressed so that the sides of the proximal
segment are approximately equal in length to the recorded lengths
of the sides of the distal region when it was in the same position.
Alternatively, if the controllable segments are of different
lengths from each other and/or the steerable distal tip, ratios of
the lengths of the sides of the steerable distal tip can be used to
propagate the selected curve down the endoscope rather than
absolute lengths. In variations where the endoscope is withdrawn,
or moved proximally, the lengths of tendons controlling more
proximal segments can be used to set the lengths of the tendons
controlling more distal segments.
[0097] 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.
The axial motion is detected by the axial motion transducer, or
datum, and the selected curve is propagated proximally along the
automatically controlled proximal portion 106 of the endoscope body
102 by the controller 45, 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.
[0098] As illustrated in FIG. 12B, 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. 12C.
[0099] 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 controller 45 commanded to
erase the previously selected curve. This can be done manually
using keyboard commands or voice commands or automatically by
programming the controller 45 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. Alternatively, the user can select a "relaxed" or "reset"
mode from the motion controller, allowing the automatically
controllable proximal portion of the endoscope, possibly including
the steerable distal tip, to be passively advanced or
withdrawn.
[0100] The endoscope body 102 is advanced through the descending
colon D until it reaches the left (splenic) flexure F.sub.1 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. 12D. 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 F.sub.r 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. 12E. 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.
[0101] FIG. 12F 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.
[0102] Thus, when the endoscope 100 is withdrawn proximally, each
time it is moved proximally, the automatically controlled proximal
portion 106 is signaled to assume the shape that previously
occupied the space that it is now in. The curve propagates distally
along the length of the automatically controlled proximal portion
106 of the endoscope body 102, and the shaped curve appears to be
fixed in space as the endoscope body 102 withdraws proximally.
Alternatively, the segments of controlled portion 28 could be made
to become flaccid and the withdrawal would then be passive.
[0103] To initialize or calibrate the endoscope 100, the entire
system may be calibrated prior to use and even during use. During
endoscope procedures, such as those described above, various errors
may accumulate in the controller and/or computer. These errors may
arise from a variety of factors, e.g., errors in detecting cable
motion, software errors in the controller and/or computer,
positioning inaccuracies, etc.
[0104] To account for such possible errors, the position of
endoscope 100 at any arbitrary position and/or depth of insertion
relative to a fixed reference point, as described above, may be
utilized as an additional reference for executing the advancement
and withdrawal by re-initializing the endoscope 100 and the system
while endoscope 100 is in use within the body of the patient. This
newly-created additional reference point may be used for advancing
the endoscope 100 further past this new reference. In this case,
selectably steerable distal portion 104 may be used to define new,
advancing conditions, as described above.
[0105] In the case of withdrawing endoscope 100 relative to the
re-initialized reference point, the distal portion 104 can remain
under the surgeon's control. Proximal portion 106 are placed under
the control of the computer and are made to conform to the
positions of the more-proximal segments at each depth of insertion
as endoscope 100 is withdrawn similarly to the method described
above.
[0106] Initialization or re-initialization may be performed
manually if so desired. To accomplish this, once the surgeon or
technician detects excessive error accumulation in the operation of
endoscope 100, or if the computer detects an error level beyond a
predetermined level, the controller may be programmed to
re-initialize periodically, e.g., every several seconds, several
minutes, or three minutes, etc., based upon the degree of error
accumulation. Alternatively, this re-initializing process may be
performed at least once during an exploratory or treatment
procedure or it may be performed an arbitrary number of times,
again depending upon the error accumulation.
[0107] The controller may be configured to continuously compare the
optimal position of each or several segments against achievable
segment position and actuation effort. When detected discrepancies
are larger than a predetermined value, a reinitialization may be
performed.
[0108] FIG. 13 shows a flow diagram 1000 of one variation for
initializing or re-initializing an endoscope device 100 during use
in, e.g., a patient. Once it has been determined to initialize,
e.g., prior to use, or re-initialize the device and system, an
initialization or re-initialization command may be issued, as in
step 1002. The endoscopic device may then be allowed to relax,
i.e., no force is applied to the tendons to actuate movement of the
segments, and assume a shape of the lumen or passageway in which
the device is positioned, as in step 1004.
[0109] After the device has assumed the new positions, the new
position information of the segments (and/or axes of the segments)
may be logged into the computer to replace and/or supplement prior
logged information with this newly logged information, as shown in
step 1006. The depth of insertion may also be newly logged, as in
step 1008.
[0110] Following logging the new positional information, it may be
determined in step 1010 whether the endoscope 100 is advancing or
withdrawing by sensing the motion, as described above. If the
endoscope 100 is advanced, normal operations may continue as in
step 1014 utilizing the newly logged information. If endoscope 100
is withdrawn, as in step 1012, the newly logged information may be
used to control segments proximally located from the
re-initialization reference point and normal operations may be
continued, as in step 1014.
[0111] 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. The present invention may also be used for
industrial applications such as inspection and exploratory
applications within tortuous regions, e.g., machinery, pipes,
etc.
[0112] In a variation of the method that is particularly applicable
to laparoscopy or thoracoscopy procedures, the steerable endoscope
can be selectively maneuvered along a desired path around and
between organs in a patient's body cavity. The distal end of the
endoscope may be 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 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 motion controller can be used to control the
automatically controlled proximal portion 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 motion
controller. Modification of the above-described assemblies and
methods for carrying out the invention, and variations of aspects
of the invention that are obvious to those of skill in the art are
intended to be within the scope of the claims.
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