Surgical blade abstract
The present invention is directed to an ultrasonic surgical blade
including a top surface, a bottom surface and a cutting-edge. The
cutting-edge is defined by a cutting-surface intermediate the top
surface and the bottom surface, and the top surface has a width
greater than the width of the bottom surface. The blade may be straight
or curved. In one embodiment of the invention, at least a portion
of the cutting-surface is substantially parallel to at least a portion
of the top surface. In still another embodiment of the invention
first and second side-walls intersect the top surface to form first
and second cutting-edges that may be sharp or blunt. Alternately,
a second cutting-edge may be defined by a second cutting surface
intermediate the top and bottom surfaces. Depending on the angle
between the intermediate cutting-surface and the top surface, the
cutting-edge may be sharp or blunt. In yet another embodiment of
the present invention, a central ridge is provided on the bottom
surface of the blade to eliminate blade burrowing and improve precision
during coagulation. The cutting-edge is optimized to increase cutting
speed of the blade while providing desirable hemostasis. The invention
is of particular benefit for breast surgery, due to its cutting
and coagulation characteristics.
Surgical blade claims
What is claimed is:
1. An ultrasonic surgical blade comprising: a flat bottom surface;
a top surface, wherein said top surface has a width greater than
said bottom surface; and a cutting-edge, wherein said cutting-edge
is defined by a first cutting-surface intermediate said top surface
and said bottom surface.
2. An ultrasonic surgical blade according to claim 1 wherein said
ultrasonic surgical blade is sterile.
3. An ultrasonic surgical blade according to claim 1 wherein the
included angle at the intersection between said top surface and
said first cutting-surface is from about 25 to about 35 degrees.
4. An ultrasonic surgical blade according to claim 1 wherein said
first cutting surface is curvilinear.
5. An ultrasonic surgical blade according to claim 1 wherein said
top surface further comprises a second cutting-surface intersecting
said first cutting-surface at said cutting-edge.
6. An ultrasonic surgical blade according to claim 5 wherein the
intersection of said first cutting-surface and said second cutting-surface
has an included angle of between about 10 to about 60 degrees.
7. An ultrasonic surgical blade according to claim 6 wherein the
included angle between said first cutting-surface and said second
cutting-surface is from about 25 to about 35 degrees.
8. An ultrasonic surgical blade according to claim 7 wherein at
least a portion of said top surface is flat, and at least a portion
of said first cutting-surface is flat, wherein said flat portion
of said top surface is substantially parallel to said flat portion
of said first cutting-surface.
9. An ultrasonic surgical blade according to claim 7 wherein said
top surface has a width about 0.002 inches to about 0.060 inches
wider than the width of said bottom surface.
10. An ultrasonic surgical blade according to claim 9 wherein said
cutting-edge is sharp.
11. An ultrasonic surgical blade according to claim 9 wherein said
cutting-edge is blunt.
12. An ultrasonic surgical blade according to claim 11 wherein
said blunt cutting-edge is square.
13. The ultrasonic surgical blade of claim 1 wherein the blade
is curved.
14. A curved ultrasonic surgical blade comprising: a bottom surface;
a top surface; a cutting-edge, wherein said cutting-edge is defined
by a first cutting-surface intermediate said top surface and said
bottom surface; and said top surface comprising a second cutting-surface
intersecting said first cutting-surface at said cutting edge.
15. A curved ultrasonic surgical blade according to claim 14 wherein
the intersection of said first cutting-surface and said second cutting-surface
has an included angle of between about 10 to about 60 degrees.
16. A curved ultrasonic surgical blade according to claim 15 wherein
the included angle between said first cutting-surface and said second
cutting-surface is from about 25 to about 35 degrees.
17. A curved ultrasonic surgical blade according to claim 16 wherein
said top surface has a width about 0.002 inches to about 0.060 inches
wider than the width of said bottom surface.
18. A curved ultrasonic surgical blade according to claim 17 wherein
said first cutting-surface is curvilinear.
19. A curved ultrasonic surgical blade according to claim 17 wherein
said cutting-edge is sharp.
20. A curved ultrasonic surgical blade according to claim 17 wherein
said cutting-edge is blunt.
21. A curved ultrasonic surgical blade according to claim 17 wherein
said curved ultrasonic blade is sterile.
22. A curved ultrasonic surgical blade according to claim 20 wherein
said blunt cutting-edge is square.
23. A curved ultrasonic surgical blade according to claim 21 wherein
at least a portion of said top surface is flat, and at least a portion
of said first cutting-surface is flat, wherein said flat portion
of said top surface is substantially parallel to said flat portion
of said first cutting-surface.
24. The curved ultrasonic surgical blade according to claim 14
wherein the top surface has a width greater than the bottom surface.
Surgical blade description
FIELD OF THE INVENTION
The present invention relates, in general, to ultrasonic surgical
blades for use in surgical instruments and, more particularly, to
an ultrasonic surgical blade with improved cutting and coagulation
features.
BACKGROUND OF THE INVENTION
Ultrasonic instruments, including both hollow core and solid core
instruments, are used for the safe and effective treatment of many
medical conditions. Ultrasonic instruments, and particularly solid
core ultrasonic instruments, are advantageous because they may be
used to cut and/or coagulate organic tissue using energy in the
form of mechanical vibrations transmitted to a surgical end-effector
at ultrasonic frequencies. Ultrasonic vibrations, when transmitted
to organic tissue at suitable energy levels and using a suitable
end-effector, may be used to cut, dissect, or cauterize tissue.
Ultrasonic instruments utilizing solid core technology are particularly
advantageous because of the amount of ultrasonic energy that may
be transmitted from the ultrasonic transducer, through the waveguide,
to the surgical end-effector. Such instruments may be used for open
procedures or minimally invasive procedures, such as endoscopic
or laparoscopic procedures, wherein the end-effector is passed through
a trocar to reach the surgical site.
Activating the end-effector (e.g. cutting blade) of such instruments
at ultrasonic frequencies induces longitudinal vibratory movement
that generates localized heat within adjacent tissue, facilitating
both cutting and coagulation. Because of the nature of ultrasonic
instruments, a particular ultrasonically actuated end-effector may
be designed to perform numerous functions, including, for example,
cutting and coagulation. The structural stress induced in such end-effectors
by vibrating the blade at ultrasonic frequencies may have a number
of undesirable effects. Such undesirable effects may include, for
example, transverse motion in the instrument waveguide that may
lead to, for example, excess heat generation in the waveguide or
premature stress failure.
Long thin ultrasonic waveguides, such as those used in instruments
for minimally invasive surgery, are particularly susceptible to
transverse vibrations introduced by imbalances in the end-effector.
For certain applications, it is desirable to include one or more
axially asymmetrical features, (e.g. blade curvature) to enhance
performance of the end-effector. It may also be desirable to design
such end-effectors to be relatively long, in order to facilitate
certain surgical procedures. A method of balancing asymmetric ultrasonic
surgical blades is described in U.S. patent application Ser. No.
09/106661 filed Jun. 29 1999 hereby incorporated herein by reference.
Although ultrasonic surgical instruments such as those described
in U.S. patent application Ser. No. 09/106661 have been eminently
successful, some areas of improvement still remain. One complaint
sometimes heard from surgeons is that cutting is too slow, or that
control is not as precise as would be desired. Ultrasonic surgical
blade edges are often dulled or rounded to slow the cutting process,
thereby providing more heat delivery to the tissue during cutting.
This improves hemostasis during cutting. It would, therefore, be
desirable to design an improved ultrasonic surgical blade. It would
further be advantageous to provide an ultrasonic surgical blade
that cuts faster, while maintaining hemostasis desired by the surgeon.
It would also be advantageous to provide an ultrasonic surgical
blade that is more controllable and precise, to providing cutting
where needed with significant control. An ultrasonic surgical instrument
is described with improved cutting and coagulation features to provide
these advantages and overcome the disadvantages of previous instruments.
SUMMARY OF THE INVENTION
The present invention is directed to an ultrasonic surgical blade
including a top surface, a bottom surface and at least one cutting-edge.
The cutting-edge is defined by a cutting-surface intermediate the
top surface and the bottom surface, and whereby the top surface
has a width greater than the width of the bottom surface. The cutting-edge
is optimized to increase cutting speed of the blade while providing
desirable hemostasis. Further, the blade may be straight or curved.
In one embodiment, at least a portion of the cutting-surface is
substantially parallel to at least a portion of the top surface.
In still a further embodiment, the cutting edge is defined by a
second cutting surface that intersects the first cutting surface
to form the cutting edge. In yet another embodiment of the invention,
the bottom surface further includes a first side-wall that intersects
the first cutting-surface to form the first cutting-edge. Depending
on the angle between the cutting-surfaces and the top surface, the
cutting-edge may be sharp or blunt. In yet another embodiment of
the present invention, a central ridge is provided on the bottom
surface of the blade to eliminate blade burrowing and improve precision
during coagulation. A second cutting edge may be formed by including
a second intermediate cutting surface formed between the top and
bottom surfaces. The second cutting edge may be further defined
by a second cutting surface intersecting the second intermediate
cutting surface and/or a second side wall intersecting the second
intermediate cutting surface to form the second cutting edge.
BRIEF DESCRIPTION OF THE DRAWINGS
The novel features of the invention are set forth with particularity
in the appended claims. The invention itself, however, both as to
organization and methods of operation, together with further objects
and advantages thereof, may best be understood by reference to the
following description, taken in conjunction with the accompanying
drawings in which:
FIG. 1 is an exploded perspective view of an ultrasonic surgical
instrument according to the present invention;
FIG. 2 is a top view of the distal end of an ultrasonic transmission
assembly according to the present invention;
FIG. 3 is a side view of the distal end of an ultrasonic transmission
assembly according to the present invention;
FIG. 4 is a bottom view of the distal end of an ultrasonic transmission
assembly according to the present invention;
FIG. 5 is a bottom perspective view of the distal end of an ultrasonic
transmission assembly according to the present invention;
FIG. 6 is a top perspective view of the distal end of the ultrasonic
transmission assembly shown in FIG. 5;
FIG. 7 is a side view of a straight blade in accordance with the
present invention;
FIG. 8 is a section view taken along line 8--8 of FIG. 7;
FIG. 9 is a side view of a curved blade according to the present
invention, including radii of curvatures;
FIG. 10 is a section view taken along line 10--10 of FIG. 9;
FIG. 10-A is an alternate embodiment section view taken along line
10--10 of FIG. 9;
FIG. 11 is a magnification of the blade edge region indicated in
FIG. 10;
FIG. 12 is a magnification of an alternate embodiment of the blade
edge region indicated in FIG. 10;
FIG. 13 illustrates a blade in accordance with the present invention
connected to an ultrasonic transducer and its associated ultrasonic
generator; and
FIG. 14 illustrates a method of deburring an ultrasonic surgical
blade in accordance with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates, in general, to ultrasonic surgical
blades for use in surgical instruments and, more particularly, to
an ultrasonic surgical blade with improved cutting and coagulation
features. A blade according to the present invention is of particular
benefit for breast surgery, due to its cutting and coagulation characteristics,
however the blade is useful for general soft tissue cutting and
coagulation. The blade may be straight or curved, and useful for
both open or laparoscopic applications.
FIG. 1 illustrates an exploded perspective view of a sterile ultrasonic
surgical instrument 10 according to the present invention. Ultrasonic
surgical instrument 10 may be sterilized by methods known in the
art such as, for example, gamma radiation sterilization, Ethelyne
Oxide processes, autoclaving, soaking in sterilization liquid, or
other known processes. In FIG. 1 ultrasonic transmission assembly
11 includes an ultrasonic end-effector, generally designated blade
12 and ultrasonic transmission waveguide 14. Ultrasonic blade 12
and ultrasonic transmission waveguide 14 are illustrated as a single
unit construction from a material suitable for transmission of ultrasonic
energy such as, for example, Ti6Al4V (an alloy of Titanium including
Aluminum and Vanadium), Aluminum, Stainless Steel, or other known
materials. Alternately, blade 12 may be separable (and of differing
composition) from waveguide 14 and coupled by, for example, a stud,
welding, gluing, or other known methods.
Ultrasonic transmission waveguide 14 is positioned in outer sheath
16 by mounting o-ring 18 and sealing ring 20. One or more additional
dampers or support members (not shown) may also be included along
ultrasonic transmission waveguide 14. Ultrasonic transmission waveguide
14 is affixed to outer sheath 16 by mounting pin 21 that passes
through mounting holes 23 in outer sheath 16 and mounting slot 25
in transmission waveguide 14.
FIG. 2 includes an ordinate system in which: the x-axis lies along
central axis 24 of ultrasonic transmission waveguide 14 while the
y-axis is the axis of curvature of treatment region 26. In the embodiments
of the invention described herein, blade 12 is affixed to the distal
end of transmission waveguide 14 at balance node 22. Central axis
24 of transmission waveguide 14 extends from the proximal end of
transmission waveguide 14 to the distal end of transmission waveguide
14. Blade 12 includes treatment region 26 located at the distal
end of blade 12. Treatment region 26 further includes rounded tip
34.
Referring to FIG. 3 treatment region 26 includes one or more cutting-edges
36. Cutting-edges 36 (only one shown) are positioned on both sides
of treatment region 26 and extend from the proximal end of treatment
region 26 to rounded tip 34. Treatment region 26 includes atop surface
30 and a bottom surface 32. Top surface 30 is substantially planar
or flat along the z-axis of the blade.
As illustrated in FIG. 4 bottom surface 32 includes side-walls
33 and central ridge 37. Central ridge 37 runs from the distal end
of balance region 28 to rounded tip 34 along the center of treatment
region 26. Central ridge 37 adds strength, stiffness and rigidity
to treatment region 26.
In FIG. 5 central ridge 37 and side-walls 33 form the substantial
portion of bottom surface 32. Side-walls 33 originate at central
ridge 37 and terminate at cutting-surface 52. Cutting-edge 36 is
defined by the intersection of top surface 30 and cutting-surface
52 as shown in FIG. 10-A. Alternatively, top surface 30 may include
a second cutting-surface 54 whereby cutting-edge 36 is defined
by the intersection of second cutting-surface 54 and cutting-surface
52 as illustrated in FIG. 10.
FIGS. 7 and 8 illustrate an alternate embodiment of the present
invention wherein top surface 300 does not include a second cutting-surface.
Treatment region 26 includes one or more cutting-edges 360. Cutting-edges
360 are positioned on both sides of treatment region 26 and extend
from the proximal end of treatment region 26 to rounded tip 340.
Treatment region 26 includes a top surface 300 and a bottom surface
320. Top surface 300 is substantially planar or flat along the z-axis
of the blade, but may alternately be curvilinear. Cutting-edge 360
is defined by the intersection of top surface 300 and cutting-surface
520.
In FIG. 9 treatment region 26 is a curved blade 31 having a blade
curvature A. In one embodiment of the present invention, blade curvature
A may be, for example, about 0.9 inches.+-.about 0.3 inches. Further,
curved blade 31 may have a thickness R of about 0.050 inches.+-.about
0.02 inches. Curved blade 31 may, in one embodiment of the invention,
include first radius of curvature M and second radius of curvature
S. In this embodiment of the invention, first radius of curvature
M and second radius of curvature S act as first and second balance
features respectively. In one embodiment of the present invention,
radius of curvature S may be, for example, about 0.25 inches.+-.about
0.125 inches. In the illustrated embodiment of the invention, curved
blade 31 may have a radius M of approximately about 0.750 inches.+-.about
0.749 inches. In one embodiment of the invention, curved blade 31
may have a length G of approximately 1.0 inches.+-.about 0.5 inches
where G is measured from node point 22 to the distal end of curved
blade 31.
In the embodiment of the invention illustrated in FIG. 10 top
surface 30 has a width C of, for example, about 0.115 inches.+-.about
0.001 inches. Central ridge 37 has a width D of, for example, about
0.030 inches.+-.about 0.003 inches. In the embodiment of FIG. 10
the cross section of curved blade 31 is formed by side-walls 33
central ridge 37 cutting-surface 52 and top surface 30. Top surface
30 has a width about 0.004 inches wider than the width of bottom
surface 32 and preferably, about 0.010 inches wider than the width
of bottom surface 32.
The cutting-edge 36 is seen in greater detail in FIG. 11. Top surface
30 is beveled, or shaved, by second cutting-surface 54. Second cutting-surface
54 intersects cutting-surface 52 with an included angle of .alpha..
Angle a has a useful range of from about 10 to about 60 degrees,
and is preferably within the range of about 25 to about 35 degrees.
The width of cutting-surface 52 has a useful range of from about
0.002 to about 0.060 inches, and is preferably within the range
of about 0.005 to about 0.020 inches. Providing cutting-edges 36
with cutting-surface 52 has the unexpected result of increasing
the cutting speed of treatment region 26 without compromising coagulation.
The embodiment of FIG. 12 illustrates an alternate way to provide
a cutting-surface to an ultrasonic blade in accordance with the
present invention. In this embodiment, side-wall 33 meets second
cutting-surface 54 through radial-cutting-surface 72. Radial cutting-surface
72 may be formed by, for example, machining side-wall 33 with a
rounded cutting tool having a radius of curvature 70. Angle .beta.
is the angle between the tangent of radial-cutting-surface 72 at
edge 36 and second cutting-surface 54. Angle .beta. has a useful
range of from about 10 to about 60 degrees, and is preferably within
the range of about 25 to about 35 degrees.
FIGS. 13 and 14 illustrate a method of deburring the edges, including
cutting-edges 36 of treatment region 26. Burrs are fragments of
material at the blade 31 edges due to the manufacturing process.
These burrs can cause inconsistent cutting speed from blade to blade
resulting in a lowered sense of precision by the surgeon during
use. It is desirable to remove the burrs to provide consistent function
from blade to blade. However, standard deburring methods are less
than optimal for preserving the advantages of cutting-surface 52
on edge 36.
Normally burrs are removed by, for example, buffing, sanding, or
chemical etching. However standard deburring methods may dull edge
36 and decrease the cutting speed of blade 31. A novel approach
to deburring ultrasonic devices such as blade 31 is to use the tuned
ultrasonic properties of the ultrasonic surgical instrument 10 to
deburr, as described below in conjunction with FIGS. 13 and 14.
In FIG. 13 ultrasonic transmission assembly 11 is shown acoustically
coupled to hand-piece 56. Hand-piece 56 is electrically connected
to generator 60 which is activated by foot-switch 58. Depressing
foot-switch 58 activates generator 60 and delivers electrical energy
to hand-piece 56. Hand-piece 56 converts the electrical energy to
ultrasonic motion of ultrasonic transmission assembly 11 and treatment
region 26. Treatment region 26 vibrates at an excursion magnitude
of 20 micrometers to 150 micrometers, and at a frequency of approximately
55.5 kilohertz.
The method of deburring ultrasonically activated devices is illustrated
in FIG. 14 using, as an example, treatment region 26 of the distal
portion of ultrasonic surgical instrument 10. A jar 64 including
a lid 66 contains an abrasive material, or media 62. Lid 66 includes
at least one opening 68 through which treatment region 26 is inserted
into media 62. Activation of treatment region 26 in media 62 deburrs
treatment region 26 while maintaining desirable qualities of treatment
region 26.
Media 62 is an abrasive material. For example, media 62 may include,
either singly or in combinations, talc, crushed walnut shells, crushed
fired ceramics, glass beads, plastic, Aluminum oxide, steel, sand,
crushed champagne bottle glass, or other known materials used for
polishing, bead-blasting, sand-blasting, or the like. For an ultrasonic
surgical instrument such as treatment region 26 it is preferable
to use crushed champagne bottle glass using particles of glass having
a mesh size of from 10 to 40 mesh, and most preferably 24 mesh.
A mesh is a size of screen or of particles passed by it in terms
of the number of openings per linear inch. A suitable media is Aluma
Glass #24 available from N. T. Ruddock, 26123 Broadway Ave., Cleveland,
Ohio 44140.
Finer mesh media 62 produces a sand-blasted appearance without
removing large burrs from treatment region 26. Coarser mesh media
62 removes large burrs from treatment region 26 and produces an
appealing finish without dulling the cutting-edges 36 and compromising
clinical efficacy. However, very course media does not remove burrs
and leaves the blade 31 with a scratched or damaged surface appearance.
Short durations of blade 31 activation in media 62 knocks off large
burrs, while maintaining cutting-edge 36 sharpness due to the motion
of cutting-edges 36 preferred direction while in contact with media
62. Two to twenty seconds of activation are sufficient to remove
all unwanted burrs without compromising sharpness, depending on
media type and mesh size. Longer durations of activation will controllably
decrease cutting-edge 36 radius, or sharpness, to optimize desired
treatment region 26 efficacy.
While preferred embodiments of the present invention have been
shown and described herein, it will be obvious to those skilled
in the art that such embodiments are provided by way of example
only. Numerous variations, changes, and substitutions will now occur
to those skilled in the art without departing from the invention.
Accordingly, it is intended that the invention be limited only by
the spirit and scope of the appended claims.
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