U.S. patent application number 15/120522 was filed with the patent office on 2017-01-12 for steerable medical device.
The applicant listed for this patent is HUMAN EXTENSIONS LTD.. Invention is credited to Yuval BLYAKHMAN, Mordehai SHOLEV.
Application Number | 20170007224 15/120522 |
Document ID | / |
Family ID | 54239492 |
Filed Date | 2017-01-12 |
United States Patent
Application |
20170007224 |
Kind Code |
A1 |
SHOLEV; Mordehai ; et
al. |
January 12, 2017 |
STEERABLE MEDICAL DEVICE
Abstract
A medical device is provided. The medical device includes an
elongated device body having a steerable portion including a
plurality of segments. The segments are co-axially mounted over at
least one elongated elastic element which is configured for
limiting rotation of the segments with respect to each other. The
medical device also includes a control wire running alongside the
elongated device body and being unrestrained at the steerable
portion such that tensioning of the control wire angles the
steerable portion from a longitudinal axis of the elongated device
body and deflects the control wire away from the steerable
portion.
Inventors: |
SHOLEV; Mordehai; (Moshav
Amikam, IL) ; BLYAKHMAN; Yuval; (Tel-Aviv,
IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HUMAN EXTENSIONS LTD. |
Natanya |
|
IL |
|
|
Family ID: |
54239492 |
Appl. No.: |
15/120522 |
Filed: |
March 31, 2015 |
PCT Filed: |
March 31, 2015 |
PCT NO: |
PCT/IL2015/050342 |
371 Date: |
August 21, 2016 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
61972518 |
Mar 31, 2014 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 2017/00738
20130101; A61B 2017/2927 20130101; A61B 2034/302 20160201; A61B
2017/00314 20130101; A61B 2017/2919 20130101; A61B 17/00234
20130101; A61M 25/0147 20130101; G02B 23/2476 20130101; A61B
2017/291 20130101; A61M 25/0136 20130101; A61B 2017/00323 20130101;
A61B 1/0055 20130101; A61B 1/0057 20130101; A61B 17/29 20130101;
A61B 1/0011 20130101 |
International
Class: |
A61B 17/00 20060101
A61B017/00; A61B 17/29 20060101 A61B017/29; A61B 1/005 20060101
A61B001/005; A61M 25/01 20060101 A61M025/01 |
Claims
1. A medical device comprising: (a) an elongated device body having
a steerable portion including a plurality of segments; (b) at least
one control wire running alongside said elongated device body and
being unrestrained at said steerable portion such that tensioning
of said at least one control wire angles said steerable portion
from a longitudinal axis of said elongated device body and deflects
said at least one control wire away from said steerable portion;
and optionally; (c) at least one elongated elastic element running
through said plurality of segments and being configured for
limiting rotation of said segments with respect to each other.
2. The medical device of claim 1, wherein each of said plurality of
segments is configured so as to limit rotation thereof with respect
to flanking segments.
3. The medical device of claim 1, wherein said at least one
elongated elastic element has a rectangular cross section.
4. The medical device of claim 1, further comprising an elastic
tubular sheath covering said steerable portion.
5. The medical device of claim 1, comprising a plurality of control
wires, each being for angling said steerable portion of said
elongated device body in a specific direction.
6. The medical device of claim 2, wherein said plurality of
segments are interlinked.
7. The medical device of claim 1, further comprising a tissue
manipulator attached to a distal end of said elongated device
body.
8. The medical device of claim 7, wherein said tissue manipulator
is a grasper, a tissue cutter, or a needle holder.
9. The medical device of claim 1, further comprising a rigid sheath
covering non-steerable portion of said elongated device body.
10. The medical device of claim 1, wherein said elongated elastic
element is a spring coil.
11. The medical device of claim 2, wherein rotation between
adjacent segments of said plurality of segments is limited by
tab-slot engagement between said adjacent segments.
12. The medical device of claim 9, wherein said control wire is
trapped between said device body and said rigid sheath at said
non-steerable portion.
13. The medical device of claim 1, further comprising at least one
retractable lever positioned at a distal end of said steerable
portion, said at least one retractable lever being attached to a
distal end of said at least one control wire.
14. A medical device comprising: (a) an elongated device body
having a steerable portion including an elastic shaft; and (b) at
least one control wire running alongside said elongated device body
and being unrestrained at said steerable portion such that
tensioning of said at least one control wire angles said steerable
portion from a longitudinal axis of said elongated device body and
deflects said at least one control wire away from said steerable
portion.
15. The medical device of claim 14, wherein said at least one
control wire is routed through a pair of guide clamps flanking said
steerable portion.
Description
FIELD AND BACKGROUND OF THE INVENTION
[0001] The present invention relates to a steerable medical device
and, more particularly, to a medical device which includes
unrestrained control wires capable of deflecting away from the
steerable portion of the medical device when tensioned.
[0002] Medical devices such as endoscopes and catheters are widely
used in minimally invasive surgery for viewing or treating organs,
cavities, passageways, and tissues. Generally, such devices include
an elongated device body which is designed for delivering and
positioning a distally-mounted instrument (e.g. scalpel, grasper or
camera/camera lens) within a body cavity, vessel or tissue.
[0003] Since such devices are delivered though a delivery port
which is positioned through a small incision made in the tissue
wall (e.g. abdominal wall), and are utilized in an anatomically
constrained space, it is desirable that the medical device or at
least a portion thereof be steerable, or maneuverable inside the
body using controls positioned outside the body (at the proximal
end of the medical device). Such steering enables an operator to
guide the device within the body and accurately position the
distally-mounted instrument at an anatomical landmark.
[0004] In order to control deflection of a steerable portion of the
device and thus steer the instrument mounted thereon, steerable
medical devices typically employ one or more control wires which
run the length of the device and terminate at the distal end of the
steerable portion or at the distal tip.
[0005] The proximal end of each control wire is connected to the
user operated handle; pulling of the wire bends the device body and
deflects the steerable portion with relation the pulled wire.
[0006] Numerous examples of steerable devices are known in the art,
see for example, U.S. Pat. Nos. 2,498,692; 4,753,223; 6,126,649;
5,873,842; 7,481,793; 6,817,974; 7,682,307 and U.S. Patent
Application Publication No. 20090259141.
[0007] Although prior art devices can be effectively steered inside
the body, the relatively small diameter of the elongated device
body (which is dictated by the diameter of the delivery port),
severely limits angle-of-deflection capabilities and increases the
pull force required to deflect the steerable device portion.
[0008] As such, it would be highly advantageous to have a steerable
medical device having a device body narrow enough for delivery
through standard delivery ports and yet capable of providing wide
angle steering of the deflectable portion within the body while
minimizing the pull force required for such steering.
SUMMARY OF THE INVENTION
[0009] According to one aspect of the present invention there is
provided medical device comprising: (a) an elongated device body
having a steerable portion including a plurality of segments; (b)
optionally, at least one elongated elastic element running through
the plurality of segments and being configured for limiting
rotation of the segments with respect to each other; and (c) at
least one control wire running alongside the elongated device body
and being unrestrained at the steerable portion such that
tensioning of the at least one control wire angles the steerable
portion from a longitudinal axis of the elongated device body and
deflects the at least one control wire away from the steerable
portion.
[0010] According to further features in preferred embodiments of
the invention described below, each of the plurality of segments is
configured so as to limit rotation thereof with respect to flanking
segments.
[0011] According to still further features in the described
preferred embodiments the at least one elongated elastic element
has a rectangular cross section.
[0012] According to still further features in the described
preferred embodiments the medical further comprises an elastic
tubular sheath covering the steerable portion.
[0013] According to still further features in the described
preferred embodiments the medical device comprises a plurality of
control wires, each being for angling the steerable portion of the
elongated device body in a specific direction.
[0014] According to still further features in the described
preferred embodiments the plurality of segments are
interlinked.
[0015] According to still further features in the described
preferred embodiments the medical device further comprises a tissue
manipulator attached to a distal end of the elongated device
body.
[0016] According to still further features in the described
preferred embodiments the tissue manipulator is a grasper, a tissue
cutter, or a needle holder.
[0017] According to still further features in the described
preferred embodiments the medical device further comprises a rigid
sheath covering non-steerable portion of the elongated device
body.
[0018] According to still further features in the described
preferred embodiments the elongated elastic element is a spring
coil.
[0019] According to still further features in the described
preferred embodiments rotation between adjacent segments of the
plurality of segments is limited by tab-slot engagement between the
adjacent segments.
[0020] According to still further features in the described
preferred embodiments the control wire is trapped between the
device body and the rigid sheath at the non-steerable portion.
[0021] According to still further features in the described
preferred embodiments the medical device further comprises at least
one retractable lever positioned at a distal end of the steerable
portion, the at least one retractable lever being attached to a
distal end of the at least one control wire.
[0022] According to another aspect of the present invention there
is provided a medical device comprising: (a) an elongated device
body having a steerable portion including an elastic shaft; and (b)
at least one control wire running alongside the elongated device
body and being unrestrained at the steerable portion such that
tensioning of the at least one control wire angles the steerable
portion from a longitudinal axis of the elongated device body and
deflects the at least one control wire away from the steerable
portion.
[0023] According to still further features in the described
preferred embodiments the at least one control wire is routed
through a pair of guide clamps flanking the steerable portion.
[0024] The present invention successfully addresses the
shortcomings of the presently known configurations by providing a
steerable medical device having a deflectable region being
configured capable of angling more than 180 degrees with respect to
a longitudinal axis of the device.
[0025] Unless otherwise defined, all technical and scientific terms
used herein have the same meaning as commonly understood by one of
ordinary skill in the art to which this invention belongs. Although
methods and materials similar or equivalent to those described
herein can be used in the practice or testing of the present
invention, suitable methods and materials are described below. In
case of conflict, the patent specification, including definitions,
will control. In addition, the materials, methods, and examples are
illustrative only and not intended to be limiting.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0026] The invention is herein described, by way of example only,
with reference to the accompanying drawings. With specific
reference now to the drawings in detail, it is stressed that the
particulars shown are by way of example and for purposes of
illustrative discussion of the preferred embodiments of the present
invention only, and are presented in the cause of providing what is
believed to be the most useful and readily understood description
of the principles and conceptual aspects of the invention. In this
regard, no attempt is made to show structural details of the
invention in more detail than is necessary for a fundamental
understanding of the invention, the description taken with the
drawings making apparent to those skilled in the art how the
several forms of the invention may be embodied in practice.
[0027] In the drawings:
[0028] FIGS. 1a-1h illustrate the present device and the operation
of the handle controlling the deflection of the steerable
portion(s) and effector end.
[0029] FIG. 2 illustrates the elongated body (fitted with grasper
end) and the drive unit components of the device of FIG. 1.
[0030] FIGS. 3a-b illustrate one embodiment of a steerable potion
of the present device.
[0031] FIGS. 4a-b illustrate another embodiment of a steerable
potion of the present device.
[0032] FIGS. 5a-d illustrate one embodiment of a link utilizable
for constructing a steerable portion of the present device (FIGS.
5a-c), and a steerable portion constructed from a plurality of
links.
[0033] FIG. 6 illustrates a steerable portion with several links
removed exposing the spring element fitted within a central core of
the links.
[0034] FIGS. 7a-h illustrate an embodiment of the present device
that includes a steerable portion fabricated from interconnected
disc-shaped links. FIGS. 7a-c illustrate isometric and side views
of the device, while FIGS. 7d-h illustrate the disc-shaped
links.
[0035] FIGS. 8a-q illustrate an embodiment of the present device
that includes two offset steerable portions deflectable to form,
for example, U-shaped (FIG. 8k) and S-shaped (FIG. 8l) articulation
configurations.
[0036] FIGS. 9a-b illustrate an embodiment of the present device
that includes a unitary flexible shaft fitted with guides for
routing the control wires. FIG. 9b illustrates deflection of the
shaft between guides.
[0037] FIGS. 9c-i illustrate another embodiment of the present
device that includes a unitary flexible shaft including cutouts for
enabling deflection. FIG. 9i illustrates deflection of the shaft
between guides.
[0038] FIGS. 9j-k illustrate a unitary flexible shaft (FIG. 9k)
constructed from disc-like links (FIG. 9j) that are pinned together
around a single rotatably-offset pivot point.
[0039] FIGS. 10a-c are images of a prototype device tested through
various articulation states and deflection angles of the steerable
portion.
[0040] FIGS. 11a-b illustrate a steerable portion composed of
transparent links.
[0041] FIG. 12 is a flowchart diagram describing a design
`algorithm` for constructing an articulating region of
predetermined properties using the teachings of the present
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0042] The present invention is of a medical device and system
which can be used in minimally invasive surgery. Specifically, the
present invention can be used to provide enhanced steering.
[0043] The principles and operation of the present invention may be
better understood with reference to the drawings and accompanying
descriptions.
[0044] Before explaining at least one embodiment of the invention
in detail, it is to be understood that the invention is not limited
in its application to the details set forth in the following
description or exemplified by the Examples. The invention is
capable of other embodiments or of being practiced or carried out
in various ways. Also, it is to be understood that the phraseology
and terminology employed herein is for the purpose of description
and should not be regarded as limiting.
[0045] Steerable medical devices for use in minimally invasive
surgery are well known in the art. Such devices typically utilize
one or more control wires operable from a proximal end of the
device positioned within the body to deflect and thus steer a
distal portion of the device positioned within the body. In order
to enable the control wire to efficiently deflect the distal
portion of the device, the longitudinal axis of the control wire
must be offset from the axis of deflection. In general, the greater
the offset, the greater deflection that can be achieved with less
pulling force applied to the control wire.
[0046] Since the diameter of minimally invasive devices is dictated
by the delivery port used to gain access to the intrabody tissues
(typically 5, 8 or 10 mm), in existing tools the offset between the
control wire and the deflection axis is in fact limited by the
diameter of the tool's shaft the diameter of the port and the
configuration of the device.
[0047] To overcome this limitation, the present inventor has
devised a unique control wire guide configuration which minimizes
the overall diameter of the device body and yet provides control
wire offset when the steerable portion is angled.
[0048] Thus, according to one aspect of the present invention there
is provided a medical device which includes a steerable intrabody
portion capable of being steered through a wide range of angles (up
to 180 degrees) and patterns such as zigzag or varied diameter
curves at one or more points along its length.
[0049] As used herein, the phrase "medical device" refers to any
device utilizable in treatment of a subject, preferably a human
subject. The medical device of the present invention is preferably
used in minimally invasive surgery wherein a steerable distal
portion thereof positioned within a body of a subject is controlled
from a proximal end positioned outside the body (extra corporeally)
via a control mechanism which preferably includes control wires.
The medical device can be used for viewing or for manipulating
tissues within any body cavity. Examples of medical devices which
can benefit from the present invention include an endoscope (e.g.
laparoscope or thorascope), a catheter, a needle holder, grasper,
Scissors, hook, stapler, retractor and the like.
[0050] The medical device of the present invention includes an
elongated device body having a distal portion which is steerable
within a body of a subject (also referred to herein as steerable
portion), preferably via at least one control wire. As is further
described herein, the steerable portion of the device can be
deflected in various directions and configurations, e.g. the entire
steerable portion can be deflected (arced) towards one direction
using a single control wire, or a first segment of the steerable
portion can be deflected in one direction while another can be
deflected in an opposite direction (zigzag and multi-plane
articulation) using two or more control wires. FIGS. 10a-c of the
Examples section which follows provides several examples the
deflection capabilities of the present device.
[0051] The elongated device body includes one or more control wires
disposed along its length. The proximal end of the control wire is
attached to control levers which are actuatable by a handle of the
medical device or by an electro-mechanical mechanism. The distal
end of the control wire is attached to the device body (at a point
past the steerable portion). The length of the control wire can be
routed within or alongside the device body with the section of wire
corresponding to the steerable portion being routed outside the
device body such that it can freely move out from the longitudinal
axis of the device body (offset) when the steerable portion is
angled.
[0052] Enabling the control wire to freely move away from the
device body at the steerable portion provides several
advantages:
[0053] (i) gradually reduces the force needed to deflect the
steerable portion once the steerable portion curves;
[0054] (ii) negates the need for wire guides at the steerable
portion (an optionally along the entire device body) thus
simplifying construction and reducing friction on the control
wires;
[0055] (iii) reduce the friction between the wire and the wire
guides;
[0056] (iv) allows to use smaller diameter wires because the force
needed to steer the articulation is significantly smaller;
[0057] (v) reduces the means of connecting the wire to the distal
end of the articulation because the force needed to steer the
articulation is significantly smaller;
[0058] (vi) (iv)+(v) allows to reduce the diameter of the device
when linear thus facilitating insertion and removal into body
(through, for example, a trocar port);
[0059] (vii) when using the tool manually, all the above a allows
the surgeon to operate the tool with much less effort;
[0060] (viii) makes the use of electro-mechanic actuators possible.
As it will be described later the significant force reducing allows
the use of very small actuators (such as motors) which enables the
design of a light weight fully motorized device;
[0061] (ix) The use of very small actuators (such as motors)
enables to operate a fully motorized device with small energy
consumption; and
[0062] (X) Enabling use of transparent materials in the steerable
portion. FIGS. 1-11b illustrate several embodiments of the present
device which is referred to herein as device 10.
[0063] FIG. 1a illustrates a laparoscopic configuration of device
10. Device 10 includes an elongated device body 12 (also referred
to herein as elongated body 12 or body 12) which includes a
steerable portion 14 fabricated from a series of segments 16 (shown
in FIGS. 5a-c).
[0064] Device body 12 can be 20-40 cm in length and 5-12 mm in
diameter. Device body 12 can be hollow or solid depending on the
use of device 10. For example, in cases where device 10 is used to
steer an endoscopic camera, device body 12 can be hollow in order
to enable routing of wires or fiber optic cables from a user
operable end (handle) to a camera or lens mounted on a distal end
of elongated device body. A hollow device body 12 can also be used
to route wires for controlling an operation of a tissue manipulator
head such as a grasper and/or for accommodating at least one
elongated elastic element for providing device body with elastic
rigidity (further described hereinbelow).
[0065] Device 10 also includes a user operable interface 18
attached to proximal end of device body 12 and an effector end 20
(e.g. tissue manipulator such as a grasper) attached to a distal
end of device body 12. Interface 18 functions in controlling and
setting a orientation and position of elongated body 12, angling of
steerable portion 14 and in operating effector end 20 (e.g.
opening/closing, rotating and angling a grasper).
[0066] For example, in the configuration shown in Figure la, a user
(e.g. surgeon) can press/release handles 300 to close and open the
jaws of the grasper, rotate interface 18 in order to rotate the
grasper jaws, and/or tilt housing 400 in order to deflect steerable
portion 14. These actions can be done separately or
simultaneously.
[0067] An interface 18 that can be used with device 10 is further
described hereinbelow. Alternatively, the device 10 can incorporate
the interface described in U.S. Provisional Patent Application No.
61/694,865, the contents of which are fully incorporated
herein.
[0068] FIG. 2 illustrates routing of control wires 22 from drive
unit 24 to a point distal to steerable portion 14. Drive unit 24
can include levers, pulleys and gears for translating hand
movements of the user (control movements) to pulling of control
wires 22. Such transfer can be mechanical (manual) or motorized. A
motorized embodiment of drive unit 16 is further described in U.S.
Provisional Patent Application No.
[0069] 61/872,727.
[0070] In the embodiment shown in FIG. 2, control wires 22 are
routed within device body 12 (e.g. under a sheath covering device
body 12 or in the tube) up to steerable portion 14. At steerable
portion 14, control wires 22 (one shown) is free from device body
12, such that angulation of steerable portion deflects control wire
22 away from the longitudinal axis of device body 12. Deflection of
the control wire away from the longitudinal axis of the device
(radially outward) increases the offset between the control wire
and the deflection axis of the elongated device body and thus
minimizes the pulling force needed to achieve deflection.
[0071] Steerable portion 14 (composed of links) is shown in greater
detail in FIGS. 3a-4b. In FIGS. 3a-b, control wires 22.sub.2
22.sub.3 are attached to device body 12 at point B and routed into
body 12 through point A.sub.2. In between, control wires 22.sub.2
22.sub.3 are free to move away from device body 12 and thus deflect
away from device body 12 when pulled to angle steerable portion 14.
FIG. 3a illustrates pulling of control wires 22.sub.2 22.sub.3,
control wire 22.sub.1 is not pulled and thus remains flush against
device body 12. Pulling of control wires 22.sub.2 22.sub.3 deflects
effector end 20 (grasper shown) in the plane between control wires
22.sub.2 22.sub.3. FIG. 3b illustrates simultaneous pulling of
control wires 22.sub.2 22.sub.3. Both control wires deflect away
from device body 12 (at steerable portion 14) and pull effector end
20 in a plane between control wires 22.sub.2 22.sub.3 resulting in
angling of effector end 20.
[0072] In the embodiment of FIGS. 3a-b, control wires 22.sub.2
22.sub.3 and 22.sub.1 are attached directly to device body 12 at
B.sub.1 B.sub.2 B.sub.3 and routed into body 12 through A.sub.1
A.sub.2 A.sub.3. In FIGS. 4a-b, control wires 22 are attached to
retractable levers 26 at a distal end thereof. Levers 26 are
disposed within slots 28 in device body 12 when device 10 is
delivered into the body. Levers 26 can be spring loaded and
sequestered within slots 28 during delivery through a port. Once
the region of device body 12 containing levers 26 exits the port
(i.e. is free of the radial constraints imposed by the port inner
wall), levers 26 can spring out; alternatively, levers 26 can fold
out when control wires 22 are pulled. In any case, once deployed,
levers 26 deflect the distal ends of control wires 22 away from
device body thus increasing leverage of control wires 22 and
further reducing the pulling force needed to deflect steerable
portion 14. When device body 12 is pulled out of the body through a
port, levers 26 collapse into slots 28 to facilitate removal
through the port.
[0073] As is mentioned hereinabove, one embodiments of device body
12 or at least steerable portion 14 is preferably constructed from
a series of links. FIGS. 5a-c illustrate one embodiment of links 30
with assembly of links 30 into steerable portion 14 illustrated in
FIG. 5d.
[0074] Links 30 preferably include several arms 32 (3 shown)
mounted around a central hub 34. As is shown in FIG. 5d, the
inter-arm space 36 accommodates control wires 22, and thus the
number of arms 32 (preferably 2-12) dictates the number of control
wires 22 used in device 10.
[0075] Link 30 is preferably fabricated from an alloy or polymer
via machining molding or the like.
[0076] Hub 34 includes a central circular opening 38 (FIG. 5b),
while each arm 32 optionally includes an opening 39 (FIG. 5a).
Opening 38 can accommodate an elongated elastic element (e.g.
spring coil 33 shown in FIG. 6 or an elastic tube) for interlinking
links 30 and providing device body 12 with rigidity and elasticity
at steerable portion 12. Openings 39 can be used to route wires for
actuating effector end 20 or for accommodating elastic rods (as an
alternative to one central rod mounted through opening 38. Openings
39 can also be used to route electrical wires to operate a motor or
a camera or jaws of a grasper or any other sensor or actuator at a
point distal to steerable portion 14. Opening 38 can also serve as
a through lumen for delivering an irrigation tube, optical fibers
and the like.
[0077] In order to prevent or limit rotation of links 30 when
control wires 22 are pulled, each link includes tabs 40 and slots
42 on opposite faces. Preferably each arm 32 includes a tab 40 and
an opposing slot 42 although the length and width can vary between
arms 32 of a single link 30. Tabs 40 of a link 30 are capable of
engaging slots 42 of an adjacent link 30, thus limiting relative
rotation of links 30.
[0078] The configuration and positioning of tabs 40 and slots 42
can be selected so as to completely limit rotation, or limit
rotation to a specific angle range (5-15 degrees) or a specific
direction etc. In any case, the engagement between tabs 40 and
slots 42 can be reversible thus allowing disengagement therebetween
when steerable portion 14 is deflected and links 30 angle with
respect to each other.
[0079] FIGS. 7a-h illustrate another embodiment of links 30, which
can be stacked as shown in FIGS. 7a-c to form steerable portion
14.
[0080] Links 30 of this embodiment of device 10 are roughly
disc-shaped and include a central opening 50, a plurality of
circumferential openings 52 (FIGS. 7d-g), indents 54 (FIGS. 7e, g,
h) and depressions 56 (FIGS. 7d, f).
[0081] Central opening 50 serves for routing one or more wires from
the device handle to effector end 20. Such wires are actuated by
the handle to control effector end 20 (e.g. open, close, rotate
grasper). Circumferential openings 52 serve for routing control
wires 22 for actuating deflection of steerable portion 14. Indents
54 and depressions 56 interconnect adjacent links 30 and enable
such links to angle with respect to each other. An elastic rod or
tube or spring can be positioned through central opening 50 to
provide elasticity to links 30.
[0082] FIG. 8a illustrates an embodiment of device 10 which
includes two independent steerable portions: 14 and 14'. Device 10
includes a device body 12 (also referred to herein as shaft 12)
with a typical diameter of 5-12 mm. The distal end of device body
12 is fitted with an effector end 20 which can be, for example, a
grasper as shown in this Figure. Steerable portion 14' includes a
proximal base link 29 which is connected to the distal end of shaft
12, a series of links 30 and a distal end link 31. Distal ends of
control wires 22'.sub.1,2,3 are connected to link 31, while the
proximal ends of these wires are connected to a drive unit 24 (FIG.
2) which is operated from the handle.
[0083] Control wires 22.sub.1,2,3 are connected to distal link 32
of steerable portion 14, and are routed through link 31 and the
bodies of links 30' to drive unit 24 (FIG. 2) which is operated
from the handle.
[0084] FIG. 8b illustrates steerable portions 14 and 14' in greater
details. Each of steerable portions 14 and 14' includes 9 identical
links (30 and 30'), however, different number of links of different
geometry can be used in each steerable portion. Tabs 40 and slots
42 (described hereinabove with respect to FIG. 5) of links 30 and
30' are also shown.
[0085] FIG. 8c is a cross sectional view of steerable portions 14
and 14'. Flexible shaft 21 (connected to drive unit 24 at its
proximal end) is positioned through holes 38, 37 of links 29, 30',
30, 31 and 32, the distal end of flexible shaft is connected to
effector 20.
[0086] Control wire 22'.sub.1 passes through hole 28'.sub.1 of link
29 and hole 36'.sub.1 of link 31; distal end of control wire
22'.sub.1 is connected to link 31 to/in hole 36'.sub.1; control
wire 22'.sub.1 is routed out of links 30'. Control wire 22.sub.1
passes through hole 27.sub.1 of link 29 and through hole 35.sub.1
of links 30' (shown in detail in FIG. 8d). At link 31, control wire
22.sup.1 deflects out through elongated opening 34.sub.1 of link 31
and runs out of links 30 to a distal connection point 38 at link
32. Control wires 22'.sub.2 and 22'.sub.3 are similar in routing
and attachment to control wire 22'.sub.1, while control wires
22.sub.2 and 22.sub.3 are similar in routing and attachment as
control wire 22.sub.1.
[0087] FIG. 8d illustrates link 30' in detail. Central hole 37
accommodates flexible shaft 21 while holes 35 accommodate control
wires 22.sub.1,2,3 (tabs 42 and slots 40 are also shown).
[0088] FIG. 8e illustrates link 31 in detail. Central hole 38
accommodates flexible shaft 21 while holes 36.sub.1,2,3 serve as
connection points for control wires 22'.sub.1,2,3. Elongated
openings 34.sub.1,2,3 route control wires 22.sub.1,2,3 out of links
30.
[0089] Deflection of portions 14 and 14' and thus steering and
articulation of shaft 12 is effected via pulling forces on control
wires 22 and 22'. If a control wire is close to the center of a
steerable portion, such as the case with control wires 22 which run
through holes 35 in steerable portion 14', then a pulling force on
these control wires results in a relatively small deflection, in
other words the effect of a pulling force on deflection is in
direct relationship to the distance between control wire 22 to a
center of a steerable portion 14. When a control wire 22 is
connected to a distal end of a steerable portion 14 and is free to
move through the proximal base, e.g. when threaded through holes
36.sub.1,2,3 in link 31, then the effect of a pulling force on
steerable portion 14 is enough to deflect it from the longitudinal
axis. This effect of the pulling force increases as steerable
portion 14 deflects since control wire 22 bows outward (radially)
and the distance between the control wire 22 and center of
steerable portion 14 increases.
[0090] FIG. 8f illustrates a configuration capable of an 80 degree
deflection, i.e. effector end 20 can assume an angle of 100 degrees
with respect to the longitudinal axis of shaft 12. Deflection of
proximal steerable portion 14' is effected by pulling (in a
proximal direction) on control wires 22'.sub.2,3.
[0091] FIG. 8g is a cross sectional view of the device of FIG. 8f
showing routing of control wires 22. A prototype constructed in
accordance with the configuration of FIGS. 8f-g is shown in FIG.
10b.
[0092] FIG. 8h illustrates a configuration capable of an 80 degree
deflection, i.e. effector end 20 can assume an angle of 100 degrees
with respect to the longitudinal axis of shaft 12. Deflection of
distal steerable portion 14 is effected by pulling (in a proximal
direction) on control wire 22.sub.1.
[0093] FIG. 8i is a cross sectional view of the device of FIG. 8h
showing routing of control wire 22.sub.1. Control wire 22.sub.1
runs through hole 35.sub.1 in links 30' of steerable portion 14'
and as such its distance from the center of steerable portion 14'
is minimal. This small distance, ensures that the pulling forces
applied on control wire 22.sub.1,2,3 will have little or no effect
on the deflection of steerable portion 14'. At the distal end of
proximal steerable portion 14', control wire 22.sub.1 runs through
elongated opening 34.sub.1 in link 31 and connects to link 32 at
point 37.sub.1. This direct connection positions control wire
22.sub.1 outward from the center of steerable portion 14, and
therefore increase the moment arm of the pulling force. This
enables steerable portion 14' to deflect (bend) under relatively
small pulling forces.
[0094] FIG. 8j illustrates routing of control wires 22.sub.1 and
22'.sub.1 and central flexible shaft 21 and the effect of wire
routing on deflection forces. In this Figure, "d" represents 1 unit
of distance, in this case, the distance between the center of hole
35.sub.1 to the center of link 30'. The following parameters are
used for calculations:
[0095] "a"--measurement of the longest arm moment of control wire
22.sub.1 from the center point of link 30'. La=1.00d;
[0096] "b"--measurement of the longest arm moment of control wire
22'.sub.1 from the center point of link 30', Lb=2.75d;
[0097] "c"--measurement of the longest arm moment of control wire
22.sub.1 from the center point of link 30, Lc=4.00d.
[0098] A force F22.sub.1 is applied to control wire 22.sub.1, thus
the moment force F22.sub.1 applies on portion 14' is:
Ma=F22.sub.1.times.La
Ma=F22.sub.1.times.1.00d
[0099] The moment the force F22.sub.1 applies on portion 14 is:
Mc=F22.sub.1.times.Le
Mc=F22.sub.1.times.4.00d
[0100] The moment applied by on portion 14 compared to the moment
applied on portion 14'' by the same force F22.sub.1 is:
Mc/Ma=F22.sub.1.times.4.00d/F22.sub.1.times.1.00d=4
[0101] The above calculations when applied to commercially
available devices, illustrate that the present invention can reduce
the wire pulling force needed for deflection by at least 25% when
compared to such commercially available devices (see Examples
section for further detail).
[0102] The bending moment on steerable portion 14 (the "target
steerable portion") caused by force (F22.sub.1) applied by control
wire 22.sub.1 is significantly greater than the bending moment on
steerable portion 14' (the "secondary steerable portion"), and as
such, a coupling effect between these two steerable portions is
minimized.
[0103] Minimizing such coupling enables the use of a simple
mechanism, such as hand operated mechanism, to steer the
articulation without the need to add a controller to the control
wires mechanism.
[0104] When using an electro-mechanical mechanism to pull the
control wires then the moments on the secondary portion may be
reduced to zero by using a controller that is programmed to apply
force on control wire 22'.sub.1. The magnitude of this force may be
calculated by:
Ma=Mb (canceling moments)
Ma=F22.sub.1.times.La=F22.sub.1.times.1.00d
Mb=F22'.sub.1.times.L=F22'.sub.1.times.2.35d
F22.sub.1.times.La=F22.sub.1.times.1.00d=F22'.sub.1.times.L=F22'.sub.1.t-
imes.2.35d
F22'.sub.1=F22.sub.1.times.1.00d2.35d
F22'.sub.1=0.42F22.sub.1
[0105] As calculated the controller will operate the actuator that
pulls control wire 22'.sub.1 in a force less than a half of force
F22.sub.1(F22'.sub.1=0.42F22.sub.1).
[0106] It will be appreciated that in cases where an
electro-mechanical drive unit is used for pulling the control
wires, than the control wires routing described above can reduce
the energy consumption of the motors controlling the first and
second steerable portions.
[0107] The routing principles described hereinabove may be used in
any combination to deflect two or more steerable portions and
generate any articulation desired. For example, FIG. 8k illustrates
"U"-shaped articulation with effector end 20 positioned at an angle
of 190 degrees. Such articulation is achieved by pulling control
wires 22'.sub.1 and 22.sub.2.
[0108] FIG. 8l illustrates an "S"-shaped articulation which can be
achieved by pulling control wires 22'.sub.1 and 22.sub.1.
[0109] FIGS. 8m-8p illustrate a device having two steerable
portions with deployable arms positioned at a distal end of each
steerable portion. Arm 39p is hingedly connected to link 31 and arm
39d is hingedly connected to link 33. Arms 39p and 39d can swing
outward and increase the distance between the end of a control wire
connected thereto and the center of the deflectable portion. FIG.
8m illustrates arms 39p and 39d in a folded position, FIG. 8n
illustrates arms 39d and 39p in an open position. FIG. 8o
illustrates "U"-shaped articulation with arms 39d and 39p in an
open position. FIG. 8p illustrates "S"-shaped articulation with
arms 39d and 39p in an open position.
[0110] FIG. 8q is a cross sectional view of the present device in a
"U"-shaped configuration with arms 39d and 39p in an open position.
In this example arms 39p and 39d have the same dimensions. The
moment arm of control wire 22.sub.1 attached to arm 39d is
5.5d.
[0111] The effect of using arms 39d and 39p on the force needed to
deflect the steerable portion can be represented by the following
calculation:
Device with no arms:
Mc=F22.sub.14.00d
Device with arms:
M.sub.armsc=F.sub.arms22.sub.1.times.5.50d
M.sub.armsc=Mc
F22.sub.1.times.4.00d=F.sub.arms22.sub.1.times.5.50d
F.sub.arms22.sub.1=F22.sub.1.times.4.00d/5.50d
F.sub.arms22.sub.1=F22.sub.1.times.4.00d/5.00d
F.sub.arms22.sub.1=0.73F22.sub.1
[0112] The foregoing describes examples of device 10 capable of
single plane articulation, however it will be appreciated that
device 10 having two or more steerable portions can be deflected to
form a multi-planar articulated configuration such as that shown in
FIGS. 10d or even a complete loop. Such multi-planar articulation
can be achieved by actuating control wires which are located at
different planes or by for example applying non symmetrical forces
on pairs of control wires.
[0113] As is mentioned herein above, any handle and mechanism can
be used with device 10 of the present invention. The construction
and operation of one embodiment of a handle utilizable with the
present device is illustrated in FIGS. 1b-h. FIGS. 1b-c illustrate
grasper head 20 and steerable portion 14 which are actuatable via
the device handle interface (18) and its internal mechanism. In
this embodiment the steerable portion is controlled by 4 control
wires 22. Steerable portion 14 is shown deflected in a direction of
pulled control wire 22.sub.2.
[0114] FIGS. 1d-e and 1g are cross sectional views of device 10
showing the mechanism in the handle that enables transfer of
interface movements to the control wires.
[0115] Control wires 22 (22.sub.1, 22.sub.2, 22.sub.3, 22.sub.4)
which are attached to a distal end of steerable portion 14, are
routed via a pair of pulleys. The grasper jaws are actuated via
mechanism 170, to hole 110a at the base of spring 110 of housing
500. Control wires 22 are prevented from slipping through spring
110 by crimp 220. The shape of crimp 220 follows the shape of the
housing of spring 110 to ensure smooth and predictable movement of
a compressed spring 110 when a control wire 22 is pushed away from
center by body 130.
[0116] Body 130 is connected to housing 500 by ball joint bearing.
Body 130 is located at the center of the mechanism, and may be
tilted with respect to housing 500, by forces applied on interface
crown 400 by a user. Control wires 22 surround body 130, when body
130 is in a neutral position each control wire 22 is pressed
against the circumferential edge of body 130 by slot 90a of bead
90.
[0117] FIG. 1f illustrates the relationship between bead 90,
control wire 22 (22.sub.1 shown) and body 130 in detail. Bead 90 is
connected firmly to control wire 22.sub.1 and divides control wire
22 into 2 contiguous regions: upper region 22.sub.1u and lower
region 22.sub.1d. Bead 90 includes a slot 90a that fits into the
circumferential edge 130a of body 130.
[0118] FIG. 1h, illustrates in details the control mechanism, shown
in a tilted position, with control wire 22.sub.1 pushed via bead
90.sub.1 away from center in order to deflect steerable portion 14.
The engagement point between circumferential edge 130a of body 130
and bead 90.sub.1, is at the inner side of slot 90a. While body 130
pushes bead 90 away from the center, opposite-positioned bead
90.sub.3 is released from circumferential edge 130a. Control wire
22.sub.3 is connected at a distal end to an opposite side of
control wire 22.sub.1. As seen in FIG. 1b, when steerable portion
is deflected by control wire 22.sub.1, the inner side of portion
14.sub.in is shortened, and the length of 14.sub.out at the
opposite side of steerable portion 14 is increased. The length of
wire 22.sub.3 must increase accordingly. Such length accommodation
by control wire 22.sub.3 is possible by compressing spring
110.sub.3.
[0119] The grasper jaws are actuated via a mechanism (FIGS. 1g-h)
which is controllable by the surgeon fingers. When handles 300 are
pressed the arms of mechanism 150 elevate piston 240 which closes
the jaws. If the surgeon releases the force applied to handles 3,
springs which are connected to the arms of mechanism 150 push
piston 24 back into body 500 and the jaws open. Piston 24 is
connected to the jaws push/pull mechanism via flexible shaft 17 and
tube 16. Flexible shaft 17 and tube 16 are also used to transfer
rotation and push-pull movement applied on housing 500. Flexible
shaft 17 may be bent without changing its length which enable
bending of portion 17 in centering element 19, without resulting an
unwanted coupled movement of opening and closing of the jaws i.e.
the grasper head and mechanism 150 does not move while steerable
portion 14 is bent. The dimension of the inner side of body 130 is
designed not to touch tube 160 when body 130 is tilted to extreme
positions.
[0120] Although a steerable portion 14 constructed from
interconnected links is advantageous in that it enables modular
design, a steerable portion 14 constructed from a unitary flexible
shaft is also envisaged herein.
[0121] A steerable portion constructed from a unitary flexible
shaft is advantageous in that it simplifies construction and
manufacturability. In addition, such a shaft is better at
insulating central electrical wires, used, for example, in
diathermia (monopolar or dipolar).
[0122] One example of such an embodiment of steerable portion 14 is
shown in FIGS. 9a-b.
[0123] Steerable portion 14 can include one or more steerable
portions 15 (three shown in FIG. 9a) interposed between guides 17
attached along a length of a flexible shaft 19. Shaft 19 can be
made of a tube fabricated from any elastic material including
stainless steel, nitinol, rubber, silicon and is typically shaped
as a solid or hollow cylinder with a diameter of 5-12 mm with wall
thickness 0.1-0.5 mm. Steerable segments 15 can be 5-30 mm in
length and guides 17 can be dimensioned to displace control wire 22
2-4 mm away from shaft 19. Guides are preferably configured with a
central ring 23 for clamping around shaft 19 and several (e.g. 2-8)
circumferentially attached rings 25 for routing of control wires
22.
[0124] Elasticity of shaft 19 ensures that steerable portion 14 or
segment 15 deflect when specific control wire or wires 22 are
pulled and linearize when control wire or wires 22 are released.
Shaft 19 is selected so as to enable elastic deflection of one or
more steerable portions 14 by 45 to 180 degrees.
[0125] Another embodiment of a unitary steerable portion 14 is
shown in FIGS. 9c-i.
[0126] This embodiment of unitary steerable portion 14 can be 5 mm
in diameter (OD) with a central lumen of at least 1.4 mm. Unitary
steerable portion 14 is constructed from a polymeric material (e.g.
polyamide, polypropylene) that is capable of providing 90 degrees
of elastic articulation (repeatedly) under a pulling force of 10 N
(looping, spatial articulation) with a bending radius of about 7
mm. When a pulling force is released, an elastic force returns
steerable portion 14 to a normal, linear configuration.
[0127] FIG. 9e illustrates a single unit 67 of unitary steerable
portion 14 which is designed to allow deflection and yet also
stabilizes steerable portion 14 when one or more control wires 22
are pulled.
[0128] Each control wire 22 of this configuration of steerable
portion 14 (three control wires 22 shown, 22.sub.1, 22.sub.2,
22.sub.3) controls deflection over an arc of 120 degrees. Such a
configuration and control wires 22 positioning stabilizes steerable
portion 14 when all three control wires (22.sub.1, 22.sub.2,
22.sub.3) are pulled.
[0129] FIG. 9f illustrates a unitary steerable portion 14
constructed from several contiguous units 67 such as those shown in
FIG. 9e. Connector 68 functions as a leaf spring-like flexure bar
(virtual joint). The extent of Bending of connector 68 is limited
by the geometry of the unit (FIG. 9g). Thus deflection of one unit
with respect to another will be equal to:
= 2 3 I 2 .sigma. H E ##EQU00001##
[0130] wherein H is the thickness of connector 68, and l is its
height. By increasing l and decreasing H each pair of adjacent
units become more flexible and less rigid. In such a configuration,
the length (L) of steerable portion 14 is determined by the bend
radius desired and can be represented by the following:
2.pi.R/4.apprxeq.L.
[0131] FIG. 9h illustrates a configuration wherein connectors 68
are offset from each other along a series of 4 units 67 to enable
defection in various directions. FIG. 9i illustrates a
configuration of steerable portion 14 that includes 10 contiguous
units 67 with offset connectors 68 and a total length of about 11
mm; force 70 is applied to the distal end of such a unified
steerable body 14 (simulating wire 22 pull) to illustrate
deflection. When such a force is released, connectors 68
elastically return steerable portion 14 to a linear (normal)
configuration.
[0132] In the configuration shown in FIGS. 9e-i, connectors 68
having an 1 of 0.5 mm, an H of 0.9 mm and a unit 67 with a diameter
of 5 mm, will enable a steerable portion 14 11 mm in length to
deflect 90 degrees under a pulling force of about 10 N.
[0133] FIGS. 9j-k illustrate another embodiment of a flexible shaft
70 constructed from units 67. Each unit 67 has a top face and a
bottom face each designed for mating with an opposite face of
adjacent unit 67 (i.e. top to bottom and vice versa). As is shown
in FIG. 9j, the bottom face of unit 74 includes two pin engaging
elements 77. The top face of unit 72 includes a single element 77
for fitting into a space between elements 77 of unit 74. When
mated, a pin 73 connects elements 77 of unit 74 and 72 and creates
a hinge for allowing articulation. Any number of units 67 can be
pinned together in various orientations (rotational offset of hinge
region) to create articulation in one of more directions.
[0134] Table 1 below exemplifies two unitary articulating regions
constructed according to the teachings of the present
invention.
TABLE-US-00001 TABLE 1 Bending Length Material Diameter Radius Rh
Rt Pt Nr A 14 mm Polyamide 5 mm 5 mm 0.4 mm 0.3 mm 1.0 mm 10 (pa12)
B 12 mm same 8 mm 8 mm 0.5 mm 0.5 mm 0.7 mm 10 Rh--vertical height
of segment Rt--vertical thickness of segment `body` Pt--vertical
height of articulating unit (two segments spaced by `hinge`)
Nr--number of units
[0135] FIG. 12 describes an `algorithm` for selecting material
properties and unit dimensions based on size and properties of the
articulating region.
[0136] Device 10 of the present invention can be used in any
minimally invasive procedure as follows. An access site is created
in a tissue wall and the shaft of device 10 is inserted through the
access site and positioned therein using interface 18. If a trocar
is used at the access site, device 10 is inserted in a straight
configuration. When the effector end of the device is positioned at
a target tissue (as ascertained via imaging), the surgeon operates
the device through interface 18 as described hereinabove. Following
completion of the procedure, the surgeon withdraws the device from
the body and the access site is closed.
[0137] Steerable portion 14 (constructed from links or as a unitary
body) of the entire shaft of device 10 can also be fabricated from
a transparent material. Use of a transparent material enables
visual inspection of control wires, optical fibers and the like
threaded through the device body.
[0138] FIG. 11a illustrates a steerable portion 14 constructed from
transparent links 30 (some of the links were removed for the sake
of clarity). Optic fibers 62.sub.1,2,3 thread through the shaft
from the handle to steerable portion 14, through holes 39 of links
30. FIG. 11b is an image of a prototype constructed with
transparent links. The transparent steerable portion enables an
operator to see control wires 22.sub.2,3 and push pull cable 21
through the transparent bodies of links 30.
[0139] An illumination source may be connected to the proximal side
of optic fibers 62.sub.1,2,3 at the handle. When illumination is
switched on, the transparent articulation radiates light out of
steerable portion 14. The light can be visualized by an operator or
an assistant, or may serve as a switch for displaying to the
operator data such as CT or MRI data of the patient of tissues near
the tip of the tool. The light may also serve to track the position
of the tool or steerable portion 14 thereof.
[0140] As used herein the term "about" refers to .+-.10%.
[0141] Additional objects, advantages, and novel features of the
present invention will become apparent to one ordinarily skilled in
the art upon examination of the following examples, which are not
intended to be limiting.
EXAMPLES
[0142] Reference is now made to the following example, which
together with the above descriptions, illustrate the invention in a
non limiting fashion.
Force Measurements in Prototype Device
[0143] A test was conducted in order to determine the force needed
to deflect a steerable portion of a prototype device by 45.degree.
and 90.degree. and to measure the travel length of the wires needed
to reach 45.degree. and 90.degree.. Two prototype devices were
constructed. The articulation used to test the forces was as
describe in details in FIG. 5. Two types of steerable portions were
tested, one constructed from 5 mm diameter links and another from 8
mm and 5 mm diameter links. Each steerable portion included 9 links
manufactured by a rapid prototype printer.
[0144] Methods
[0145] The shaft of the prototype device was fixed to a table and
positioned such that one of the control wires resided on the top
side of the shaft. A force measurement device (Shimpo FGN-5b) was
attached to this control wire and was fixed to a linear rail. In
order to measure forces, the force measurement device was driven
away from the shaft until the desired angle of the articulation was
measured. The force was recorded and the travel of device was
measured.
[0146] Results
[0147] Table 2 below summarizes the test results of two prototypes
and a prior art Cambridge articulation unit.
As is shown by the results presented in this table, the forces
needed to deflect the steerable portion of the present invention
were 10% and 15% (present device 5 or 8 mm respectively) of the
forces needed to deflect a commercial tool (Cambridge Endo).
[0148] Thus, the present device design requires significantly less
(6-10 folds less) force by the operator to deflect the steerable
portion. This will enable a surgeon to perform surgery using a
manual handle without having to apply large forces, thus
substantially improving operability and decreasing device-related
fatigue. In addition, when used with an electro-mechanical handle,
the present device would not require bulky motors and batteries but
would rather be fully operable using small motors and battery packs
which would considerably lighten the device and enhance
maneuverability thereof.
[0149] Another advantage of the present device is shown in FIGS.
10a-c which demonstrate the range of articulation and angles of
deflection possible with the present device. The present device is
capable of 2D and 3D articulation and deflection greater than 180
degrees due to the configuration of the links and in particular the
unique routing of cable therein and/or on.
[0150] It is appreciated that certain features of the invention,
which are, for clarity, described in the context of separate
embodiments, may also be provided in combination in a single
embodiment. Conversely, various features of the invention, which
are, for brevity, described in the context of a single embodiment,
may also be provided separately or in any suitable
subcombination.
[0151] Although the invention has been described in conjunction
with specific embodiments thereof, it is evident that many
alternatives, modifications and variations will be apparent to
those skilled in the art. Accordingly, it is intended to embrace
all such alternatives, modifications and variations that fall
within the spirit and broad scope of the appended claims. All
publications, patents and patent applications mentioned in this
specification are herein incorporated in their entirety by
reference into the specification, to the same extent as if each
individual publication, patent or patent application was
specifically and individually indicated to be incorporated herein
by reference. In addition, citation or identification of any
reference in this application shall not be construed as an
admission that such reference is available as prior art to the
present invention.
* * * * *