U.S. patent application number 11/555889 was filed with the patent office on 2007-03-29 for ultrasonic surgical blade and instrument having a gain step.
Invention is credited to Kevin L. Houser, Steven K. Neuenfeldt, Foster B. Stulen.
Application Number | 20070073325 11/555889 |
Document ID | / |
Family ID | 34551459 |
Filed Date | 2007-03-29 |
United States Patent
Application |
20070073325 |
Kind Code |
A1 |
Stulen; Foster B. ; et
al. |
March 29, 2007 |
ULTRASONIC SURGICAL BLADE AND INSTRUMENT HAVING A GAIN STEP
Abstract
An ultrasonic surgical blade, and an instrument, having a gain
step. The blade body has, in any half wave length of the
ultrasonic-surgical-blade body, a first vibration antinode, a
vibration node, a second vibration antinode, and a gain step. The
gain step is located between the second vibration antinode and the
first vibration antinode. The gain step is spaced apart from the
vibration node by a gain-step distance greater than 5% of the
distance between the second vibration antinode and the first
vibration antinode. The instrument includes the blade, a handpiece
having an ultrasonic transducer, and an ultrasonic transmission rod
whose proximal end is operatively connected to the ultrasonic
transducer and whose distal end activates the blade. In one option,
the first vibration antinode is the distal tip, and the gain step
is located between the vibration node and the distal tip, resulting
in an increased active length of the blade.
Inventors: |
Stulen; Foster B.; (Mason,
OH) ; Neuenfeldt; Steven K.; (Cincinnati, OH)
; Houser; Kevin L.; (Springboro, OH) |
Correspondence
Address: |
DONALD EDWARD MC INNIS
2636 SUTRO DRIVE
SAN JOSE
CA
95124
US
|
Family ID: |
34551459 |
Appl. No.: |
11/555889 |
Filed: |
November 2, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10701588 |
Nov 5, 2003 |
7163548 |
|
|
11555889 |
Nov 2, 2006 |
|
|
|
Current U.S.
Class: |
606/169 |
Current CPC
Class: |
A61B 17/320068 20130101;
A61B 2017/320072 20130101; A61B 2217/005 20130101; A61B 2017/320089
20170801; A61B 2017/22018 20130101; A61B 2017/32008 20130101 |
Class at
Publication: |
606/169 |
International
Class: |
A61B 17/32 20060101
A61B017/32 |
Claims
1. An ultrasonic surgical blade comprising an
ultrasonic-surgical-blade body having a longitudinal axis, having a
distal tip which is a most-distal vibration antinode, having a
most-distal vibration node, having a second-most-distal vibration
antinode, and having a gain step, wherein the longitudinal axis
consists essentially of a first geometric solid having a
substantially constant first transverse cross-sectional area from
the gain step to the distal tip and a second geometric solid having
a substantially constant second transverse cross-sectional area
from the gain step to the second-most-distal vibration antinode
wherein at least one of the first and second transverse
cross-sectional areas surrounds a void.
2. The ultrasonic surgical blade of claim 1, wherein the second
transverse cross-sectional area is different than the first
transverse cross-sectional area.
3. The ultrasonic surgical blade of claim 1, wherein the void
includes a first longitudinal hole which is disposed in the first
geometric solid and which extends proximally from the distal
tip.
4. The ultrasonic surgical blade of claim 3, wherein the void
includes a second longitudinal hole which is disposed in the second
geometric solid and which is in fluid communication with the first
longitudinal hole, and wherein the first and second longitudinal
holes are adapted for irrigation and/or suction.
5. The ultrasonic surgical blade of claim 3, also including a
membrane, which covers the first longitudinal hole, and which is
removably or permanently attached to the first geometric solid at
the distal tip.
6. The ultrasonic surgical blade of claim 1, wherein the first
geometric solid has a first mass, extends from the gain step to the
distal tip, and has a non-constant first transverse cross-sectional
area, wherein the second geometric solid has a second mass, extends
from the gain step to the second-most-distal vibration antinode,
and has a non-constant second transverse cross-sectional area, and
wherein the second mass is different than the first mass.
7. The ultrasonic surgical blade of claim 6, wherein the shape and
size of the first external perimeter of the first transverse
cross-sectional area is substantially equal to the shape and size
of the second external perimeter of the second transverse
cross-sectional area.
8. The ultrasonic surgical blade of claim 7, wherein at least one
of the first and second transverse cross-sectional areas surrounds
a void.
9. The ultrasonic surgical blade of claim 8, wherein the void
includes a first longitudinal hole which is disposed in the first
geometric solid and which extends proximally from the distal
tip.
10. The ultrasonic surgical blade of claim 9, wherein the void
includes a second longitudinal hole which is disposed in the second
geometric solid and which is in fluid communication with the first
longitudinal hole, and wherein the first and second longitudinal
holes are adapted for irrigation and/or suction.
11. The ultrasonic surgical blade of claim 9, also including a
membrane, which covers the first longitudinal hole, and which is
removably or permanently attached to the first geometric solid at
the distal tip.
12. The ultrasonic surgical blade of claim 1, wherein the
ultrasonic-surgical-blade body has a longitudinal axis, has an
active length, and is substantially asymmetric about the
longitudinal axis along at least a portion of the active
length.
13. The ultrasonic surgical blade of claim 12, wherein the
ultrasonic-surgical-blade body is curved.
Description
RELATED APPLICATIONS
[0001] The application is a continuation of U.S. patent
application, Ser. No. 10/701,588, filed on Nov. 5, 2003.
FIELD OF THE INVENTION
[0002] The present invention relates generally to ultrasonic
surgical blades and ultrasonic surgical instruments which include
ultrasonic surgical blades, and more particularly to those having a
gain step.
BACKGROUND OF THE INVENTION
[0003] Ultrasonic surgical instruments are known which include
ultrasonic surgical blades. A handpiece of a known ultrasonic
surgical instrument includes an ultrasonic transducer which is
powered by an ultrasonic generator through a cable. An ultrasonic
transmission rod of the instrument has a proximal end and a distal
end, wherein the proximal end is operatively connected to the
ultrasonic transducer. An ultrasonic surgical blade is activated by
the distal end of the ultrasonic transmission rod. Known blade
shapes include straight blades and asymmetric about a longitudinal
axis or about a curved centerline of the blade.
[0004] A known ultrasonic surgical blade is a cylindrical blade
which has a distal tip, a most-distal vibration node (a vibration
node being a point of substantially zero displacement), and a
second most-distal vibration antinode (a vibration antinode being a
point of maximum displacement relative to all other points in a
half wave), wherein the most-distal vibration antinode is the
distal tip. Longitudinal ultrasonic vibration of the blade
generates motion and heat in the contacted tissue, wherein the heat
primarily provides the means for the blade to cut and/or coagulate
patient tissue. The blade has a gain step located a distance from
the most-distal vibration node which is less than 5% of the
distance between the distal tip and the second-most-distal
vibration antinode because locating the gain step close to the
most-distal vibration node maximizes the vibration amplitude gain.
The known blade consists of a larger-diameter right-circular
geometrically-solid cylinder from the second most-distal vibration
antinode to the most-distal vibration node. The known blade
consists of a smaller-diameter right-circular geometrically-solid
cylinder from the most-distal vibration node to the distal tip. The
change in diameter provides a gain in vibration amplitude for the
smaller-diameter section of the blade equal to the ratio of the
transverse cross-sectional areas of the larger diameter blade
section to the smaller diameter blade section when the gain step is
located at the node.
[0005] The active length of an ultrasonic surgical blade is defined
by applicants as the distance from the distal tip to where the
vibration amplitude (i.e., the longitudinal vibration amplitude)
has fallen to 50% of the tip amplitude. The blade is not considered
useful beyond its active length. The active length is about 15 mm
for a straight cylindrical titanium rod at a resonant frequency of
about 55.5 kHz.
[0006] It is known in ultrasonic welding of plastics to provide an
ultrasonic welding rod having a gain step, such as a discontinuity
between a larger and a smaller rod diameter, which is located
between the most-distal vibration node and the distal end of the
welding horn and which is spaced apart from the most-distal
vibration node of the welding rod by a distance less than 5% of the
distance between the second-most-distal vibration antinode and the
distal end of the welding rod. It is also known in ultrasonic
welding of plastics to provide an ultrasonic welding rod with a
hole or a slot to provide a gain in longitudinal vibration
amplitude.
[0007] What is needed is an improved ultrasonic surgical blade, and
an improved ultrasonic surgical instrument which includes an
ultrasonic surgical blade, having a longer or shorter active
length.
SUMMARY OF THE INVENTION
[0008] A first expression of an embodiment of the invention is for
an ultrasonic surgical blade including an ultrasonic-surgical-blade
body. The ultrasonic-surgical-blade body has a distal tip which is
a most-distal vibration antinode, has a most-distal vibration node,
has a second-most-distal vibration antinode, and has a gain step.
The gain step is located between the second-most-distal vibration
antinode and the distal tip, and the gain step is spaced apart from
the most-distal vibration node by a gain-step distance greater than
5% of the distance between the second-most-distal vibration
antinode and the distal tip.
[0009] A second expression of an embodiment of the invention is for
an ultrasonic surgical instrument including a handpiece, an
ultrasonic transmission rod, and an ultrasonic surgical blade. The
handpiece includes an ultrasonic transducer. The ultrasonic
transmission rod has a proximal end and a distal end, wherein the
proximal end is operatively connected to the ultrasonic transducer.
The ultrasonic surgical blade is activated by the distal end and
includes an ultrasonic-surgical-blade body. The
ultrasonic-surgical-blade body has a distal tip which is a
most-distal vibration antinode, has a most-distal vibration node,
has a second-most-distal vibration antinode, and has a gain step.
The gain step is located between the second-most-distal vibration
antinode and the distal tip, and the gain step is spaced apart from
the most-distal vibration node by a gain-step distance greater than
5% of the distance between the second-most-distal vibration
antinode and the distal tip.
[0010] A third expression of an embodiment of the invention is for
an ultrasonic surgical blade including an ultrasonic-surgical-blade
body. The ultrasonic-surgical-blade body has, in any half wave
length of the ultrasonic-surgical-blade body, a first vibration
antinode, a vibration node, a second vibration antinode, and a gain
step. The gain step is located between the second vibration
antinode and the first vibration antinode. The gain step is spaced
apart from the vibration node by a gain-step distance greater than
5% of the distance between the second vibration antinode and the
first vibration antinode.
[0011] Several benefits and advantages are obtained from one or
more of the expressions of the embodiment of the invention.
Applicants found that locating a gain step having a gain greater
than unity (i.e., an amplification step) further than
conventionally taught from the most-distal vibration node toward
the distal tip further increased the active length of the
ultrasonic surgical blade even though the vibration amplitude gain
was less than when conventionally locating the gain step closer to
the most-distal vibration node. Applicants determined that locating
the gain step further than conventionally taught from the
most-distal vibration node toward the second-most-distal vibration
antinode should shorten the half wave length of the ultrasonic
surgical blade. Applicants also determined that such changes in
active and half wave lengths of the ultrasonic surgical blade would
also result from gain steps having gains less than unity (i.e., a
deamplification step) but with a deamplification step causing a
decrease in active length where an identically located
amplification step would cause an increase in active length and
with a deamplification step causing an increase in active length
where an identically located amplification step would cause a
decrease in active length. Being able to lengthen or shorten the
active length of an ultrasonic surgical blade offers advantages for
particular surgical applications, as can be appreciated by those
skilled in the art.
[0012] The present invention has, without limitation, application
in robotic-assisted surgery.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a schematic view of a first embodiment of an
ultrasonic surgical instrument including a first embodiment of an
ultrasonic surgical blade of the invention;
[0014] FIG. 2 is a longitudinal cross-sectional view of the
most-distal one-half wavelength, including the distal tip, of the
ultrasonic surgical blade of FIG. 1;
[0015] FIG. 3 is a longitudinal cross-sectional view of the
most-distal one-half wavelength, including the distal tip, of a
second embodiment of the surgical blade of FIG. 1; and
[0016] FIG. 4 is a longitudinal cross-sectional view of the
most-distal one-half wavelength, including the distal tip, of a
third embodiment of the surgical blade of FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
[0017] Before explaining the present invention in detail, it should
be noted that the invention is not limited in its application or
use to the details of construction and arrangement of parts
illustrated in the accompanying drawings and description. The
illustrative embodiment of the invention may be implemented or
incorporated in other embodiments, variations and modifications,
and may be practiced or carried out in various ways. Furthermore,
unless otherwise indicated, the terms and expressions employed
herein have been chosen for the purpose of describing the
illustrative embodiment of the present invention for the
convenience of the reader and are not for the purpose of limiting
the invention.
[0018] It is understood that any one or more of the
following-described expressions of an embodiment, examples, etc.
can be combined with any one or more of the other
following-described expressions of an embodiment, examples, etc.
For example, and without limitation, a gain feature of a reduced
diameter can be combined with a gain feature of a hole.
[0019] Referring now to the drawings, FIGS. 1-2 illustrate a first
embodiment of the invention. A first expression of the first
embodiment of FIGS. 1-2 is for an ultrasonic surgical blade 10
including an ultrasonic-surgical-blade body 12 having a distal tip
14 which is a most-distal vibration antinode (a vibration antinode
being a point of maximum displacement relative to all other points
in a half wave), having a most-distal vibration node 16 (a
vibration node being a point of substantially zero displacement),
having a second-most-distal vibration antinode 18, and having a
gain step 20. The gain step 20 is disposed between the
second-most-distal vibration antinode 18 and the distal tip 14 and
is spaced apart from the most-distal vibration node 16 by a
gain-step distance 22 greater than 5% of the distance 24 between
the second-most-distal vibration antinode 18 and the distal tip
14.
[0020] In one implementation of the first expression of the first
embodiment of FIGS. 1-2, the gain step distance 22 is between
substantially 25% and substantially 45% of the distance 24 between
the second-most-distal vibration antinode 18 and the distal tip 14.
Those of ordinary skill in the art, employing the teachings of the
invention for the location of the gain step 20, can create
analytical blade models and evaluate them using a computer program
to optimize design trade-offs between increased or decreased active
length of the ultrasonic surgical blade and increased or decreased
amplitude of the longitudinal ultrasonic vibrations for locating
the gain step 20 substantially away from the most-distal vibration
node 16 in the direction of the distal tip 14 or in the direction
of the second-most-distal vibration antinode 18.
[0021] In one example of the first expression of the first
embodiment of FIGS. 1-2, between the second-most-distal vibration
antinode 18 and the distal tip 14, the maximum vibration amplitude
of the ultrasonic-surgical-blade body 12 proximal the gain step 20
is less than the maximum vibration amplitude of the
ultrasonic-surgical-blade body 12 distal the gain step 20. In this
example, the gain of the gain step 20 is greater than unity and
results from a reduction in mass of the ultrasonic-surgical-blade
body 12 between the gain step 20 and the distal tip 14 compared to
the mass of the ultrasonic-surgical-blade body 12 between the gain
step 20 and the second-most-distal vibration antinode 18.
[0022] In a different embodiment, not shown, between the
second-most-distal vibration antinode and the distal tip, the
maximum vibration amplitude of the ultrasonic-surgical-blade body
proximal the gain step is greater than the maximum vibration
amplitude of the ultrasonic-surgical-blade body distal the gain
step. In this embodiment, the gain of the gain step is less than
unity and results from an increase in mass of the
ultrasonic-surgical-blade body between the gain step and the distal
tip compared to the mass of the ultrasonic-surgical-blade body
between the gain step and the second-most-distal vibration
antinode. This embodiment can be easily visualized, in one example,
by switching the locations of the distal tip 14 and the
second-most-distal vibration antinode 18 in FIG. 2.
[0023] In one enablement of the first expression of the first
embodiment of FIGS. 1-2, the gain step 20 is disposed between the
most-distal vibration node 16 and the distal tip 14 resulting in an
increased active length of the ultrasonic surgical blade 10. In a
different embodiment, not shown, the gain step is disposed between
the most-distal vibration node and the second-most-distal vibration
antinode resulting in a decreased half wave length of the
ultrasonic surgical blade. This embodiment can be easily visualized
by moving the gain step 20 between the most-distal vibration node
16 and the second-most-distal vibration antinode 18 in FIG. 2.
[0024] In one illustration of the first expression of the first
embodiment of FIGS. 1-2, the ultrasonic-surgical-blade body 12 has
a longitudinal axis 26 and consists essentially of a first
geometric solid 28 having a substantially constant first transverse
cross-sectional area from the gain step 20 to the distal tip 14 and
a second geometric solid 30 having a substantially constant second
transverse cross-sectional area from the gain step 20 to the
second-most-distal vibration antinode 18. The second transverse
cross-sectional area is different than the first transverse
cross-sectional area. In one variation, the shape and size of the
first external perimeter of the first transverse cross-sectional
area is substantially equal to the shape and size of the second
external perimeter of the second transverse cross-sectional area.
In one modification, at least one of the first and second
transverse cross-sectional areas surrounds a void 32. In one
construction, the void 32 includes a first longitudinal hole 34
which is disposed in the first geometric solid 28 and which extends
proximally from the distal tip 14. Applicants found that locating
the gain step 20 at the point where the gain equaled the square
root of the ratio of the transverse cross-sectional areas of the
second geometric solid 30 to the first geometric solid 28 optimized
the increase in the active length of the blade. In one arrangement,
the void 32 includes a second longitudinal hole 36 which is
disposed in the second geometric solid 30 and which is in fluid
communication with the first longitudinal hole 34, and the first
and second longitudinal holes 34 and 36 are adapted for irrigation
and/or suction. In another arrangement, the ultrasonic surgical
blade 10 also includes a membrane 38 which has a composition
substantially the same as the composition of the
ultrasonic-surgical-blade body 12, which covers the first
longitudinal hole 34, and which is removably or permanently
attached to the first geometric solid 28 at the distal tip 14. It
is noted that the membrane 38 would be removed from the first
geometric solid 28 in FIG. 2 when irrigation and/or suction is
desired. Alternatively, membrane 38 may be made from a permeable
fabric, such as a wire mesh or screen, or sintered mesh made from
titanium or other appropriate material to facilitate irrigation
and/or suction.
[0025] In a different embodiment, not shown, the
ultrasonic-surgical-blade body has a longitudinal axis and consists
essentially of a first geometric solid and a second geometric
solid. The first geometric solid has a first mass, extends from the
gain step to the distal tip, and has a non-constant first
transverse cross-sectional area. The second geometric solid has a
second mass, extends from the gain step to the second-most-distal
vibration antinode, and has a non-constant second transverse
cross-sectional area. The second mass is different than the first
mass. This embodiment is easily visualized, in one example, by
considering the second longitudinal hole 36 to have a diameter
which decreases from the second-most-distal vibration antinode 18
to the gain step 20 and the first longitudinal hole 34 to have a
diameter which increases from the gain step 20 to the distal tip 14
in FIG. 2. The variations, modifications, etc. of the preceding
paragraph are equally applicable to this embodiment.
[0026] In a further embodiment, not shown, the ultrasonic surgical
blade body has a longitudinal axis and consists essentially of a
first geometric solid having a first mass and having a first axial
length extending from the gain step to the distal tip and a second
geometric solid having a second mass and having a second axial
length extending from the gain step to the second-most-distal
vibration antinode. The second mass is different than the first
mass. One of the first and second geometric solids has a
substantially constant transverse cross-sectional area along its
corresponding axial length, and a different one of the first and
second geometric solids has a non-constant transverse
cross-sectional area along its corresponding axial length. This
embodiment is easily visualized, in one example, by considering the
first longitudinal hole 34 to have a diameter which increases from
the gain step 20 to the distal tip 14 in FIG. 2. The variations,
modifications, etc. of the second preceding paragraph are equally
applicable to this embodiment.
[0027] In one design of the first expression of the first
embodiment of FIGS. 1-2, the ultrasonic-surgical-blade body 12 has
a longitudinal axis 26 and is substantially symmetrical about the
longitudinal axis 26. In another design, not shown, the
ultrasonic-surgical-blade body has a longitudinal axis, has an
active length, and is substantially asymmetric about the
longitudinal axis along at least a portion of the active length. In
one variation, the ultrasonic-surgical-blade body is curved. This
variation is easily visualized, in one example, by curving the
distal portion of the ultrasonic-surgical-blade body 12 upward from
the longitudinal axis 26 in FIG. 2.
[0028] In one deployment of the first expression of the first
embodiment of FIGS. 1-2, the ultrasonic-surgical-blade body 12 has
at least one gain feature 40 selected from the group consisting of:
a discrete change in outer diameter or perimeter, a taper, a
longitudinal hole, a discrete change in diameter of a longitudinal
hole, a transverse hole, a surface flat, and a surface slot. It is
noted that, in this deployment, the gain step 20 is the location of
the portion of the gain feature 40 which is closest to the
most-distal vibration node 16. It is also noted that the term
"hole" includes a through hole and a non-through hole. Other gain
features are left to the artisan.
[0029] FIG. 3 illustrates a second embodiment of the ultrasonic
surgical blade 110 of the invention. In this embodiment, the
ultrasonic-surgical-blade body 112 has an additional gain step 142
which is spaced-apart from the gain step 120, which is disposed
between the second-most-distal vibration antinode 118 and the
distal tip 114, and which is spaced apart from the most-distal
vibration node 116 by a gain-step distance 122 greater than 5% of
the distance 124 between the second-most-distal vibration antinode
118 and the distal tip 114. The ultrasonic-surgical-blade body 112
has a longitudinal axis 126 and a longitudinally hole 134, wherein
the longitudinal hole has a shoulder 144 defining the additional
gain step 142.
[0030] A third embodiment of an ultrasonic surgical blade 210 is
shown in FIG. 4, wherein the ultrasonic-surgical-blade body 212
consists essentially of a right-circular first geometrically-solid
cylinder 288 from the gain step 220 to the distal tip 214. In this
embodiment, the ultrasonic-surgical-blade body 212 consists
essentially of a right-circular second geometrically-solid cylinder
230 from the gain step 220 to the second-most-distal vibration
antinode 218. The diameter of the first geometrically-solid
cylinder 288 is less than the diameter of the second
geometrically-solid cylinder 230. It is noted that in this
embodiment, the gain feature 240 is a reduced diameter from the
distal tip 214 to the gain step 220 which reduces mass and which
creates the first geometrically-solid cylinder 288. The gain step
220 is disposed between the second-most-distal vibration antinode
218 and the distal tip 214 and is spaced apart from the most-distal
vibration node 216 by a gain-step distance 222 greater than 5% of
the distance 224 between the second-most-distal vibration antinode
218 and the distal tip 214.
[0031] In one construction of the first expression of the first
embodiment of FIGS. 1-2, the ultrasonic-surgical-blade body 12
consists essentially of titanium. In other constructions, blade
bodies consist essentially of aluminum, a ceramic, sapphire, or any
other material that transmits ultrasound in an efficient manner.
Mathematical analysis of various titanium blade designs using the
described principles of the invention calling for locating the gain
step 20 substantially away from the most-distal vibration node 16
in the direction of the distal tip 14 achieved increases in the
active length of the ultrasonic surgical blade 10 up to 40%.
Applicants have seen increases up to 60% in theory. As previously
mentioned, the active length of an ultrasonic surgical blade 10 is
defined as the distance from the distal tip 14 to where the
vibration amplitude (i.e., the longitudinal vibration amplitude)
has fallen to 50% of the tip amplitude. The blade is not considered
useful beyond its active length. The active length is about 15 mm
for a straight cylindrical titanium rod at a resonant frequency of
about 55.5 kHz without applying the principles of the invention. An
increase in active length up to about 5 mm can be expected using
the described principles of the invention when the gain step 20 is
disposed between the most-distal vibration node 16 and the distal
tip 14.
[0032] In one arrangement, the ultrasonic surgical blade 10 is used
alone as the end effector of an ultrasonic surgical instrument. In
another arrangement, the ultrasonic surgical blade 10 is used with
a clamp arm (not shown) to create a shears end effector of an
ultrasonic surgical instrument for cutting and/or coagulating
patient tissue.
[0033] A second expression of the first embodiment of FIGS. 1-2 is
for an ultrasonic surgical instrument 46 including a handpiece 48,
an ultrasonic transmission rod 50, and an ultrasonic surgical blade
10. The handpiece 48 includes an ultrasonic transducer 52. The
ultrasonic transmission rod 50 has a proximal end and a distal end,
wherein the proximal end is operatively connected to the ultrasonic
transducer 52. The ultrasonic surgical blade 10 is activated by the
distal end and includes an ultrasonic-surgical-blade body 12. The
ultrasonic-surgical-blade body 12 has a distal tip 14 which is a
most-distal vibration antinode, has a most-distal vibration node
16, has a second-most-distal vibration antinode 18, and has a gain
step 20. The gain step 20 is disposed between the
second-most-distal vibration antinode 18 and the distal tip 14 and
is spaced apart from the most-distal vibration node 16 by a
gain-step distance 22 greater than 5% of the distance 24 between
the second-most-distal vibration antinode 18 and the distal tip
14.
[0034] In one enablement of the second expression of the first
embodiment of FIGS. 1-2, there is also included an ultrasonic
generator 54, activated by a foot pedal 56, and a cable 58
operatively connecting the ultrasonic generator 54 and the
ultrasonic transducer 52 of the handpiece 48. In one construction,
the ultrasonic surgical blade 10 is a monolithic portion of the
ultrasonic transmission rod 50. In another construction, the
ultrasonic surgical blade is a separate piece and is attached to
the ultrasonic transmission rod. It is noted that the embodiments,
implementations, examples, illustrations, etc. previously described
for the ultrasonic surgical blade are equally applicable to the
ultrasonic surgical instrument.
[0035] A third expression of the first embodiment of FIGS. 1-2 is
for an ultrasonic surgical blade including an
ultrasonic-surgical-blade body having, in any half wave length of
the ultrasonic-surgical-blade body, a first vibration antinode, a
vibration node, a second vibration antinode, and a gain step,
wherein the gain step is disposed between the second vibration
antinode and the first vibration antinode, and wherein the gain
step is spaced apart from the vibration node by a gain-step
distance greater than 5% of the distance between the second
vibration antinode and the first vibration antinode. It is noted
that the third expression does not limit the location of the half
wave to the last half wave length of the blade body as with the
previously presented second expression, and that apart from the
second expression's location of the half wave, the embodiments,
implementations, examples, illustrations, etc. previously described
for the second expression are equally applicable to the third
expression.
[0036] Several benefits and advantages are obtained from one or
more of the expressions of the embodiment of the invention.
Applicants found that locating a gain step having a gain greater
than unity (i.e., an amplification step) further than
conventionally taught from the most-distal vibration node toward
the distal tip further increased the active length of the
ultrasonic surgical blade even though the vibration amplitude gain
was less than when conventionally locating the gain step closer to
the most-distal vibration node. Applicants determined that locating
the gain step further than conventionally taught from the
most-distal vibration node toward the second-most-distal vibration
antinode should shorten the half wave length of the ultrasonic
surgical blade. Applicants also determined that such changes in
active and half wave lengths of the ultrasonic surgical blade would
also result from gain steps having gains less than unity (i.e., a
deamplification step) but with a deamplification step causing a
decrease in active length where an identically located
amplification step would cause an increase in active length and
with a deamplification step causing an increase in active length
where an identically located amplification step would cause a
decrease in active length. Being able to lengthen or shorten the
active length of an ultrasonic surgical blade offers advantages for
particular surgical applications, as can be appreciated by those
skilled in the art.
[0037] The foregoing description of several expressions and
embodiments of the invention has been presented for purposes of
illustration. It is not intended to be exhaustive or to limit the
invention to the precise forms disclosed, and obviously many
modifications and variations are possible in light of the above
teaching. For example, as would be apparent to those skilled in the
art, the disclosures herein of the ultrasonic surgical blade and
ultrasonic surgical instrument have equal application in robotic
assisted surgery taking into account the obvious modifications of
such systems, components and methods to be compatible with such a
robotic system.
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