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| United States Patent | 5501654 |
| Link to this page | http://www.wikipatents.com/5501654.html |
| Inventor(s) | Failla; Stephen J. (Cincinnati, OH);
Stokes; Michael J. (Gates Mills, OH);
Price; Daniel W. (Loveland, OH);
Rarey; Charles M. (Akron, OH);
Thompson; Bennie (Cincinnati, OH) |
| Abstract | An elastically deformable element having multiple stacked strips for
articulation in an endoscopic surgical instrument. The deformable element
is usable in a variable retractor and an instrument having an articulating
housing. The working section of the retractor variably moves from a curved
configuration when outside of a sheath to a substantially straightened
configuration when inside the sheath. |
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Title Information  |
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Drawing from US Patent 5501654 |
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Endoscopic instrument having articulating element |
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| Publication Date |
March 26, 1996 |
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| Filing Date |
August 16, 1994 |
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| Parent Case |
This application is a continuation, of application Ser. No. 08/092,326,
filed Jul. 15, 1993, now abandoned. |
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Title Information |
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Description |
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FIELD OF THE INVENTION
This invention relates generally to surgical instruments; and more
particularly, the invention relates to an endoscopic surgical instrument
for insertion through a trocar cannula. The endoscopic surgical instrument
in accordance with the present invention includes an articulating element
which deforms elastically.
BACKGROUND OF THE INVENTION
The burgeoning field of endoscopic surgery has created a demand for a whole
new set of articulating endoscopic surgical instruments for insertion
through a trocar cannula. These instruments have evolved from similar
instruments used in open surgery.
In open surgery, the working sections of retractors and other articulating
instruments are made to specific non-linear shapes and sizes to conform to
the specific organs or anatomical structures for which they were designed.
In endoscopic surgery, these instruments often cannot fit through trocar
cannulas. Therefore, a means must be employed wherein a substantially
straightened instrument fits through a trocar cannula and articulates to a
curvilinear or other non-linear shape after it is extended beyond the end
of the cannula. Some prior art endoscopic devices achieve such
articulation by means of linked elements in an articulating working
section. Other prior art devices achieve such articulation by employing a
single, deformable piece which forms at least part of the articulating
working section.
The prior art includes variable retractors for endoscopic use wherein a
retractable, deformable working section slides in and out of a sheath.
When the working section is retracted, it is substantially straightened
within the sheath and the sheath is extendable through a trocar cannula.
After the sheath is extended through a trocar cannula, the working section
is extended from the sheath and assumes a working, curvilinear
configuration.
Typically, the deformable working section is a single curved strip which
assumes a curved configuration in an unstressed state. The strip is
elastically deformable from a curved configuration to a substantially
straightened position. It is desirable to be able to bend the working
section from a relatively small radius of curvature to a substantially
straightened configuration.
The prior art also includes endoscopic instruments wherein an articulating
section includes an articulating housing that contains a single,
deformable strip. Typically, the strip assumes a substantially
straightened configuration in an unstressed state. When the housing is
articulated, the strip is elastically deformed to a curved configuration.
It is desirable to be able to bend the strip to a relatively small radius
of curvature.
The design and construction of an elastically deformable working section is
limited by the properties of the materials used. Deformable working
sections have been constructed from materials such as nitinol, which is a
metal alloy composed of 50 percent nickel and 50 percent titanium and is
relatively expensive.
The prior art further includes deformable working sections constructed from
shape memory alloys. A description of these alloys and their use in the
construction of medical instruments, including endoscopic surgical
instruments, is discussed in U.S. Pat. Nos. 4,665,906 and 5,067,957. These
shape memory alloys are also relatively expensive.
More conventional materials, such as spring steel, have less elasticity and
therefore are less desirable for use in prior art designs of a deformable
working section. For example, if desiring a portion or all of the working
section to have a radius of curvature of approximately 5/16 of an inch
using a spring temper stainless steel strip, the thickness of the strip is
limited to no more than about 0.007 inches, which is the approximate
maximum thickness of spring steel that will elastically bend between a
straightened configuration and a 5/16 inch radius of curvature.
Unfortunately a 0.007 inch thick strip of steel does not provide much
stiffness or resistance to deflection while under load.
By comparison, a strip of nitinol having a thickness of 0.018 inches can
elastically bend between a substantially straightened configuration and a
5/16 inch radius of curvature. The stiffness of a 0.018 inch thick nitinol
strip is about five times greater than the stiffness of a 0.007 inch thick
spring steel strip.
While using nitinol strengthens a deformable curved working section of an
articulating endoscopic surgical instrument, its main drawback is its high
cost. It would be desirable to construct the deformable working section
from a low cost materials such as spring steel, having properties similar
to that of nitinol. It would be desirable to develop variations of
surgical instruments employing such a deformable working section to
perform a variety of surgical functions.
SUMMARY OF THE INVENTION
The present invention comprises an endoscopic surgical instrument that is
extendable through a trocar cannula and has an elastically deformable
working section that is constructed from at least two adjacent strips of
elastically deformable material.
One embodiment of the surgical instrument in accordance with the invention
has an elongated element having a distal end portion and a proximal end
portion. The distal end portion is variably movable between a retracted
position wherein the distal end portion is inside a sheath and a series of
extended positions wherein the distal end portion is outside the sheath.
The distal end portion has a deformable working section which is
elastically movable from a curved configuration when the working section
is outside the sheath to a substantially straightened configuration when
the working section is inside the sheath.
The deformable working section has at least two layers or strips which are
positioned adjacent each other and constructed so as to cause the working
section to be biased towards its curved configuration. The strips are
relatively thin and slidably connected to each other so as to permit them
to be longitudinally slidable relative to each other in at least one
section.
In accordance with a preferred embodiment of the invention, the curved
working section is constructed from at least two strips of stainless steel
which are elastically bendable from a curved configuration to a
substantially straightened configuration. The strips have a thickness in a
range of about 0.002 inches to about 0.020 inches, and the number of steel
strips is in the range of two to six. The radius of curvature of each
strip is in a range of about 0.10 inches to 2.0 inches.
In accordance with a preferred embodiment, the working section has four
strips of 301 stainless steel having a thickness of approximately 0.007
inches and having a radius of curvature of approximately 0.25 inches. The
working section has a curvature of approximately 180 degrees in the fully
extended position. The distal end portion, including the working section,
is covered with a shrink wrap plastic tube.
The proximal end portion of the elongated element is a connecting rod that
is connected to the curved working section inside the sheath. The
connecting rod extends rearwardly from the curved working section and is
inserted into a handle that is connected to the proximal end of the
sheath.
The handle has a driver mechanism connected to the connecting rod for
variably moving the elongated element, including the proximal and distal
end portions, between a retracted position and any of a series of extended
positions. Preferably the driver mechanism includes a sliding gear rack
connected to the connecting rod and a rotatable pinion mechanism which is
actuated by a thumbwheel. In an alternative embodiment, the driver
mechanism includes a push rod extending rearwardly from the gear rack.
In accordance with alternative embodiments of the invention, the distal end
portion of the elongated element may include a paddle, scoop, scalpel,
cotton tip, or cautery tip.
In accordance with another alternative embodiment of the invention, the
elongated element has multiple distal end portions which separate and form
a flared arrangement when in the extended position.
In accordance with another alternative embodiment of the invention, there
are multiple elongated elements having one or more distal end portions
which are oriented so as to form opposing fingers when in the extended
position. Each of the elongated elements is connected to a separate driver
mechanism so as to permit each elongated element to be individually and/or
sequentially actuated.
In accordance with another embodiment of the invention, an elongated
element is contained within an articulating housing. The elongated element
has an elastically deformable working section that articulates with the
articulating housing.
BRIEF DESCRIPTION OF THE DRAWINGS
A more complete appreciation of this invention, and many of the attendant
advantages thereof will be readily apparent as the same becomes better
understood by reference to the following detailed description, when
considered in conjunction with the accompanying drawings in which like
reference numerals indicate the same or similar components, wherein:
FIG. 1 is an elevational view of an endoscopic surgical device constructed
in accordance with the invention;
FIG. 2 is a cross-sectional, elevational view of the endoscopic surgical
device in accordance with the invention;
FIG. 3 is an elevational view of an elongated element in accordance with
the invention;
FIG. 4 is an elevational view of the multiple layers of the distal end
portion of the elongated element;
FIG. 5 is an elevational view of the distal end portion wrapped in a
plastic tube;
FIG. 6 is a top view of the distal end portion shown in FIG. 5;
FIG. 7 is an elevational view of a distal end portion having a rounded tip;
FIG. 8 is an elevational view of the assembly of strips used to make a
distal end portion with a rounded tip as shown in FIG. 7;
FIG. 9 is an elevational view of the strips shown in FIG. 8 after being
wrapped in a plastic tube;
FIG. 10 is a partial, cross-sectional view of a distal end portion with a
rounded tip that is retracted into a sheath;
FIG. 11 is an elevational view of an endoscopic surgical instrument in
accordance with the invention that is extended through a trocar cannula
wherein the distal end portion is extended into its curved configuration;
FIG. 12 is a partial view of the working section of a distal end portion
extended approximately 90 degrees from a sheath;
FIG. 13 is an elevation view of a scalpel attached to a distal end portion;
FIG. 14 is a view of the scalpel shown in FIG. 13 along the line 14--14;
FIG. 15 is an enlarged plan view of a paddle attached to a distal end
portion;
FIG. 16 is a side view of the paddle shown in FIG. 15;
FIG. 17 is an enlarged plan view of a scoop attached to a distal end
portion;
FIG. 18 is a side view of the scoop shown in FIG. 17;
FIG. 19 is an enlarged side view of cotton tip on a distal end portion;
FIG. 20 is a partial view of the working section of a distal end portion
extended approximately 270 degrees from a sheath;
FIG. 21 is a partial elevational view of an alternative embodiment of the
invention having an S-shaped distal end portion;
FIG. 22 is a partial elevational view of an alternative embodiment of the
invention having a distal end portion with multiple curves in the same
direction;
FIG. 23 is a partial elevational view of an alternative embodiment of the
invention having a distal end portion with multiple curves in the same
direction, each curve having a different radii of curvature;
FIG. 24 is a plan view of a three-fingered distal end portion extending
from a sheath;
FIG. 25 is an elevational view of the three fingered distal end portion
shown in FIG. 24;
FIG. 26 is a cross-sectional view taken along the line 26--26 in FIG. 25;
FIG. 27 is a partial elevational view of an alternative embodiment of the
invention having two opposed distal end portions;
FIG. 28 is an elevational view of the two opposed distal end portions in
FIG. 27 wherein the distal end portions are fully separated;
FIG. 29 is a perspective view of an alternative embodiment of the invention
which includes two elongated elements wherein one of the elongated
elements having three fingers is extended from the sheath and around an
internal organ;
FIG. 30 is a perspective view of the embodiment shown in FIG. 29 wherein a
second elongated element having two fingers is extended from the sheath
and around the other side of the internal organ; and
FIG. 31 is a partial cross-sectional view of an alternative embodiment of
the invention which includes a housing with an articulating joint and an
elongated deformable element contained therein.
DETAILED DESCRIPTION OF THE INVENTION
The following is a detailed description of the invention. The detailed
description is not intended to be an exhaustive description of all
embodiments within the scope of the invention and is not intended to limit
the scope of the claims to the disclosed embodiments. Other embodiments
within the scope of the claims will be apparent to those skilled in the
art.
Referring to FIGS. 1 and 2, the endoscopic surgical instrument of this
invention 8 has two basic portions: an endoscopic portion 10 and a handle
portion 12. The endoscopic portion includes a sheath 14 that encloses an
elongated element, as described in detail below, which is longitudinally
slidable within the sheath 14. Preferably, the sheath 14 is stainless
steel and has a steel spacer or tongue 15 affixed inside of the distal end
of the sheath 14.
Referring to FIG. 3, the elongated element 16 is an assembly comprising a
proximal end portion 18 and distal end portion 20 that are connected by a
pin connection 19. The proximal end portion 18 is preferably a stainless
steel rod. The distal end portion 20 defines a curved working section 22.
Referring to FIG. 4, the working section 22 has at least two curved layers
or strips 24 which are positioned adjacent each other. The strips 24 are
relatively thin and slidably connected to each other so as to permit them
to be longitudinally slidable relative to each other.
Preferably, the strips 24 of the distal end portion 20 are constructed from
stainless steel having a thickness in the range of about 0.002 inches to
about 0.020 inches. There are preferably four strips in the curved working
section 22, each constructed from fully hardened 301 stainless steel which
is about 0.007 inches thick.
Also, there may be a fifth strip 26 (FIG. 4) in the straight section of the
distal end portion 20 to add rigidity. The fifth strip is preferably
constructed from fully hardened 301 stainless steel which is somewhat
thicker than the other strips. Other comparable materials that are
suitable for surgical use, having similar bending and strength
characteristics and having similar dimensions, may also be used.
The strips 24 are constructed so as to be biased toward a curved
configuration (FIG. 4). The radius of curvature of the working section 22
is in the range of from about 0.10 inches to about 1.5 inches. The radius
of curvature is preferably about 0.25 inches.
The multiple strips 24 of the working section 22 are slidably connected to
each other so that during bending and straightening of the working section
22 the individual strips 24 bend individually and slide relative to each
other rather than bending as a monolithic unit. This bending and sliding
of the individual strips enhances elastic bending of the working section
as a whole between its curved configuration and a substantially
straightened configuration. Elastic bending refers to bending without
yielding.
Referring to FIG. 5, the curved strips 24 of the distal end portion 20 are
slidably connected to each other with a plastic tube 26. The plastic tube
26 permits the enclosed strips to slide relative to each during the
bending and straightening of the curved working section 22. Preferably,
the plastic tube 26 is a tubing sold under the trademark KYNAR.RTM. by
Raychem Corporation.
The plastic tubing 26 is slipped over the distal end portion 20, cut off
slightly beyond the distal tip, and then shrunk with an application of
heat. Referring to FIG. 6, the tubing 26 is preferably engaged by a series
of notches 28 in a straight section of the distal end portion 20 so as to
minimize slippage of the strips 24 relative to each other in the straight
section while permitting such slippage in the curved working section 22.
Using a plastic tube 26 to cover the distal end portion 20 has the
advantage of providing a soft touch when the working section 22 of the
distal end portion 20 comes into contact with delicate internal organs.
Thus, the danger of trauma is reduced.
The plastic tubing also has the advantage of providing a smooth surface to
minimize friction between the distal end portion 20 and the sheath 14 when
the distal end portion is being moved into or out of the sheath.
It is preferable to provide an elongated hole 30 in the distal end portion
20 (FIG. 6) for receiving a pin 19 that is inserted through the hole 30
and connecting the distal end portion 20 and the proximal end portion 18
of the elongated element 16 (FIG. 3). This permits the longitudinal
movement of the strips 24 relative to each other when the strips bend.
In an alternative embodiment (not illustrated), the strips of the distal
end portion may be rigidly connected at only one point located in, or
adjacent to, the curved working section by brazing, welding, etc. A rigid
connection at only one point permits the strips to slide relative to each
other at all other locations as they are moved between a curved
configuration and substantially straightened configuration.
Referring to FIG. 7, in an alternative embodiment, the tip 29 of the distal
end portion 20 is looped. Referring to FIG. 8, the loop is constructed
from three strips 31 which are stacked on the outside of a fourth strip
having an extended tip 32. A fifth reinforcing straight strip 33 runs
along the bottom of the stacked strips. The entire stack of strips is
wrapped with a plastic tubing 34 as shown in FIG. 9. Then the tip is bent
around to form the loop 29 as shown in FIG. 7. As seen in FIG. 10, the
width of the loop 29 is less than the inside diameter of the sheath 14 so
that the loop can be fully withdrawn inside the sheath.
The loop construction of the tip 29 of the distal end portion 20 has the
advantage of providing a rounder, more blunt tip which is less likely to
cause inadvertent trauma when it is inserted into a body cavity. Further,
the open end of the plastic tubing 34 is turned inwardly and away from
tissue in the body cavity where it might contact and collect unwanted
tissue.
Referring to FIGS. 1 and 2, the handle portion 12 includes a handle 36 that
is connected to the proximal end of the sheath 14. In accordance with a
preferred embodiment, the handle 36 is molded plastic and has recesses to
hold and retain a flange 38 or other protrusion on the sheath (FIG. 2) so
as to rigidly connect the sheath to the handle.
Referring to FIG. 2, the rod 18 extends proximally into the interior of the
handle 36 wherein it is connected to a gear rack 44 through a pin
connection 42. Preferable, the gear rack 44 is molded plastic. The rod 18
and gear rack 44 assembly slide longitudinally as a single unit within the
handle 36.
The gear rack 44 engages a pinion gear 48 which is connected to a
thumbwheel 50. The pinion 48 is preferably plastic and is molded integral
with one of the two halves of the plastic thumbwheel 50 and rigidly
attached to the other half. The pinion 48 is located between the two
halves of the thumbwheel 50 and acts as a spacer separating them.
An axle pin 52 extends outwardly from each side of the thumbwheel 50 and is
held and retained by corresponding holes (not shown) in the interior of
the handle 36. Thus, the pinion 48 and thumbwheel 50 are rotatably
connected to the handle so as to permit rotation of the pinion and
thumbwheel relative to the handle.
The gear rack 44 extends rearwardly between the two halves of the
thumbwheel 50 as it engages the pinion 48. When the thumbwheel and pinion
are rotated, the pinion drives the gear rack in a longitudinal direction
(forwardly or rearwardly depending upon the direction of rotation of the
thumbwheel and pinion). Thus, the thumbwheel, pinion and gear rack operate
as a driver mechanism for moving the rod 18 in a longitudinal direction.
A detent mechanism may be provided for restricting rotation of the
thumbwheel 50 and thereby controlling incremental longitudinal movement of
the thumbwheel 50 and driver mechanism. Referring to FIG. 2, the detent
mechanism consists of a plastic strip 58 or "clicker" affixed to the
handle 36 and extending into corresponding notches on the exterior of the
thumbwheel 50. The clicker 58 rides in the notches of the thumbwheel 50
and thus acts as a ratchet-type mechanism. Preferably, the restriction
against distal movement of the gear rack 44 is greater than the
restriction against proximal movement.
Movement of the gear rack 44 in the proximal direction is limited by a stop
pin 59. (FIG. 2). Movement in the distal direction is limited by a
shoulder 45 against which the distal end of the gear rack 44 makes
contact.
In an alternative embodiment, the driver mechanism also includes a push rod
54 which is rigidly connected to the rear end of the gear rack 44, as
shown in phantom lines in FIG. 2. The push rod 54 extends rearwardly from
the gear rack through a hole in the rear end of the handle 36. Preferably,
the push rod 54 is plastic. The push rod 54 may be used for gross
adjustments of the driver mechanism, or when heavier loads are
anticipated.
Referring to FIG. 11, the endoscopic surgical instrument of this invention
8 is designed to function as a variable retractor that is extendable
through a trocar cannula 60. In order to insert the instrument into a
trocar cannula 60, the distal end portion 20, must be retracted into the
sheath 14 to avoid interference as the sheath 14 is inserted into the
trocar cannula 60.
When the distal end portion 20 is retracted into the sheath 14, the working
section 22 is straightened from its unstressed curved configuration to a
substantially straightened configuration. Since the working section 22
comprises strips 24 (FIG. 4), each strip 24 will bend independently and
slide relative to one another as the working section 22 is straightened.
This separate and independent bending of the various strips 24 permits the
working section 22 to have more resilience than a comparable monolithic
construction of the same total thickness. As a result of this resilience,
the working section 22 may be substantially straightened from a curved
configuration having a much smaller radius of curvature than would be
possible in a comparable monolithic structure of the same material and
dimensions.
During usage as a retractor, the distal end portion 20, with its layered
construction, has a sufficient amount of "give" in order to avoid trauma
when the surgical instrument is inadvertently moved or jostled.
After the distal end portion 20 is fully retracted into the sheath 14, the
sheath 14 is inserted into the trocar cannula 60 and pushed through the
cannula until it emerges from the end of the cannula inside a body cavity
(FIG. 11). Then, the distal end portion 20 is moved distally to its
extended position. As the distal end portion 20 emerges, it travels around
its original r | | |
