U.S. patent application number 15/415543 was filed with the patent office on 2017-06-01 for ultrasonic surgical apparatus with silicon waveguide.
The applicant listed for this patent is Ethicon LLC. Invention is credited to Danik Brand, Juergen Burger, William D. Dannaher, Timothy G. Dietz, Franz Friedrich, Herbert Keppner, Robert Lockhart, Phillippe Margairaz, William A. Olson, Sora Rhee, Jean-Paul Sandoz, Foster B. Stulen, John W. Willis.
Application Number | 20170151708 15/415543 |
Document ID | / |
Family ID | 50070672 |
Filed Date | 2017-06-01 |
United States Patent
Application |
20170151708 |
Kind Code |
A1 |
Dietz; Timothy G. ; et
al. |
June 1, 2017 |
ULTRASONIC SURGICAL APPARATUS WITH SILICON WAVEGUIDE
Abstract
Ultrasound surgical apparatus are disclosed, including: medical
ultrasound handpieces with proximally mounted ultrasound radiators
configured to create a distally-focused beam of ultrasound energy,
in combination with distal guide members for control of focal point
depth; medical ultrasound handpieces with proximally mounted
ultrasound radiators configured to create a distally-focused beam
of ultrasound energy, in combination with distal rolling members
for manipulability and control of focal point depth; medical
ultrasound handpiece assemblies with coupled end effectors
providing a probe with a probe dilation region configured to have
an average outside diameter that is equal to or greater than the
average outside diameter of a probe tip and neck; as well as
junctions to an ultrasonically inactive probe sheath; medical
ultrasound handpiece assemblies with coupled end effectors having
positionable, ultrasonically inactive probe sheath ends slidably
operable to both cover and expose at least a probe tip; and
ultrasound transducer cores including a transducer structure
affixed to a longitudinally elongated, generally planar, single
crystal or polycrystalline material waveguide.
Inventors: |
Dietz; Timothy G.; (Wayne,
PA) ; Stulen; Foster B.; (Mason, OH) ; Olson;
William A.; (Lebanon, OH) ; Dannaher; William D.;
(Cincinnati, OH) ; Willis; John W.; (Milford,
OH) ; Rhee; Sora; (Pennsylvania Furnace, PA) ;
Burger; Juergen; (Ipsach, CH) ; Margairaz;
Phillippe; (La Chaux-de-Fonds, CH) ; Lockhart;
Robert; (Lausanne, CH) ; Friedrich; Franz;
(Den Haag, NL) ; Brand; Danik; (Savagnier, CH)
; Keppner; Herbert; (Colombier, CH) ; Sandoz;
Jean-Paul; (Cormondreche, CH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ethicon LLC |
Guaynabo |
PR |
US |
|
|
Family ID: |
50070672 |
Appl. No.: |
15/415543 |
Filed: |
February 16, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13745385 |
Jan 18, 2013 |
|
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|
15415543 |
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|
12857399 |
Aug 16, 2010 |
8882792 |
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13745385 |
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61233945 |
Aug 14, 2009 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29C 66/01 20130101;
A61B 2017/320098 20170801; A61N 2007/0082 20130101; B29C 65/48
20130101; A61N 7/00 20130101; A61N 2007/0078 20130101; A61B
2217/007 20130101; A61B 2017/00473 20130101; A61N 7/02 20130101;
B29L 2031/753 20130101; A61B 2217/005 20130101; B06B 3/00 20130101;
A61N 2007/0034 20130101; A61B 2017/32007 20170801; A61B 8/4272
20130101; Y10T 156/1062 20150115; A61M 2207/00 20130101; A61B
2017/320088 20130101; A61B 2017/320089 20170801; A61M 37/0092
20130101; A61B 2017/00964 20130101; A61B 2017/306 20130101; A61B
2017/320073 20170801; G10K 11/24 20130101; A61B 2017/2253 20130101;
A61B 2017/320084 20130101; Y10T 156/10 20150115 |
International
Class: |
B29C 65/48 20060101
B29C065/48; A61M 37/00 20060101 A61M037/00; B29C 65/00 20060101
B29C065/00; A61N 7/02 20060101 A61N007/02 |
Claims
1. A method of manufacturing an ultrasonic core for an ultrasonic
surgical instrument, the method comprising the steps of: selecting
a single crystal piezoelectric material and cutting the material to
form a plate having major faces coincident with the <011>
crystallographic plane; adding at least one planar electrode member
to a major face of the plate; bonding the opposite major face of
the plate to a side of a longitudinally elongated, generally planar
waveguide; and after the bonding step, applying a poling current
across the at least one planar electrode member and the plate to
pole the single crystal piezoelectric material in the <011>
crystallographic direction.
2. The method of claim 1, wherein the single crystal piezoelectric
material is cut in with a zxt +0.degree. cut direction, with a
ratio of longitudinal extent to lateral extent between edge of
greater than 5 to 1, and with a ratio of longitudinal extent to
thickness of greater than 5 to 1.
3. The method of claim 1, wherein the single crystal piezoelectric
material is cut in with a zxt +45.degree. cut direction, with a
ratio of longitudinal extent to lateral extent between edges of
greater than 3.5 to 1, and with a ratio of longitudinal extent to
thickness of greater than 3.5 to 1.
4. The method of claim 1, wherein the step of adding the at least
one planar electrode member includes adding a second planar
electrode member to the opposite major face of the plate.
5. A method of manufacturing an ultrasonic core for an ultrasonic
surgical instrument, the method comprising the steps of: obtaining
both a transducer having a first longitudinal extent and a carrier
having a second, shorter longitudinal extent; bonding the
transducer to a side of the carrier to form a subassembly in which
the ends of the transducer project longitudinally beyond the ends
of the carrier; applying a pair of poling electrodes to the ends of
the transducer in the subassembly and applying a poling current
longitudinally through the transducer via the pair of poling
electrodes; and bonding the opposite side of the carrier of the
subassembly to a side of a longitudinally elongated, generally
planar waveguide.
6. The method of claim 5, wherein the step of bonding the
transducer includes applying a discontinuous pattern of balls or
edge-to-edge oriented strips of bonding material to the mutually
opposing sides of the transducer and the carrier.
7. The method of claim 6, further including the step of
underfilling transducer of the subassembly with a second,
conductive bonding material after the applying step.
8. The method of claim 7, wherein the carrier includes a plurality
of through-holes, and the second, conductive bonding material is
introduced to the space between the mutually opposing sides of the
transducer and the carrier through the plurality of through-holes.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 13/745,385 filed on Jan. 18, 2013, which is a
continuation-in-part of U.S. Non-provisional application Ser. No.
12/857,399, filed on Aug. 16, 2010, now granted U.S. Pat. No.
8,882,792, issue date Nov. 11, 2014, which claims the benefit of
U.S. Provisional Application No. 61/233,945, filed on Aug. 14,
2009, the entire contents of which are incorporated herein by
reference.
FIELD
[0002] The various embodiments relate to an ultrasonic surgical
apparatus and, more particularly, to ultrasonic surgical
instruments having a generally planar, monolithic or composite
silicon waveguide.
BACKGROUND
[0003] Human skin is composed of two major layers, the epidermis
and the dermis. Below these layers lies the hypodermis, which is
not usually classified as a layer of skin. The thinner outer layer
of the skin, the epidermis, provides a barrier to the external
environment. The epidermis is typically about 0.05 to 1.5 mm thick
(varying from its minimum at the eyelids to its maximum over the
palms and soles of the feet). It is composed of many different cell
types including keratinocytes, melanocytes, and Langerhan cells.
Keratinocytes are the major cell type (being about 75 to 80% of the
total number of cells), and are responsible for keeping water in
the body and keeping other harmful chemicals and pathogens out. The
epidermis is made up of a stratified squamous epithelium with an
underlying basement membrane. It contains no blood vessels, and is
nourished by diffusion from the dermis.
[0004] The thicker inner layer of the skin, the dermis, is the
major component of human skin. The dermis, or corium, is typically
about 0.3 to 5 mm thick (varying from its minimum at the eyelids to
its maximum over the back). It is composed of a network of
connective tissue, which provides strength, elasticity, and
thickness to the skin, and contains other structures including
capillaries, nerve endings, hair follicles, smooth muscle, glands,
and lymphatic tissue. The main cell type of the dermis is the
fibroblast, which is responsible for the synthesis and secretion of
dermal matrix components such as collagen, elastin, and
glycosaminoglycans. Collagen provides the strength, elastin the
elasticity, and glycosaminoglycans the moistness and plumpness of
the skin. With ageing, the thickness of the dermal layer is
reduced, and this is believed to be partially responsible for the
formation of wrinkles in ageing skin.
[0005] The hypodermis, also commonly referred to as the
subcutaneous fat layer or subcutaneous tissue, lies below the
dermis. Its purpose is to attach the skin to underlying bone and
muscle as well as to supply the dermis with blood vessels and
nerves. It is made up of loose connective tissue and elastin. The
main cell types are fibroblasts, macrophages, and adipocytes. The
hypodermis contains about 50% of total body fat, the fat serving as
padding, insulation, and an energy reserve for the body.
[0006] Facial aging occurs as the result of several factors:
inherent changes within the skin, the effects of gravity, the
effects of facial muscles acting on the skin (dynamic lines), soft
tissue loss or shift, bone loss, and a gradual loss of tissue
elasticity. The epidermis begins to thin, causing the junction with
the dermis to flatten. Collagen also decreases, and bundles of
collagen, which give the skin turgor, become looser and lose
strength. When the skin loses elasticity it is less able to resist
stretching. The skin begins to wrinkle as a result of gravity,
muscle pull, and tissue changes. Water loss and a breakdown of the
connective bonds between cells also weakens the barrier function of
the skin, which can cause the skin's pore size to increase.
[0007] As a person ages, the face loses volume, soft tissue, and
fat. The appearance of jowls and folds is usually caused by the
drooping of facial tissues and the folding of skin over areas where
it is attached to and supported by the muscles below. Due to the
reduction in soft tissue, the face appears more hollow. In various
facial areas such as the forehead, eyes, nose, midface, and lower
face, changes relating to aging have been well documented. For
example, in the forehead area, the forehead and brow droop over
time, which lowers the eyebrows and causes the upper eyelid skin to
bunch. Forehead lines appear when one tries to hold the brows and
eyelids up to counteract these changes. It is well known that the
eye area is often the first facial feature to show signs of aging.
Skin changes around the eyes occur earlier than in the rest of the
face since the skin is thinnest here. The skin in this area also
contains fewer glands and is subjected to constant blinking,
squinting, rubbing, and pulling.
[0008] The midface area ages when the cheeks begin to droop,
causing nasolabial folds, which are the lines that run from the
sides of the nose to the corners of the mouth. It is known to treat
these folds with facial fillers. In the nose area, the nose appears
to elongate. Common causes of elongation are thinning of the soft
tissue and loss of elasticity, which causes "drooping of the tip"
and unmasking of the bone, creating a new hump.
[0009] In the lower face area, facial tissues descend, causing
so-called "laugh lines." It is known to treat these folds and lines
with facial fillers. Further down on the lower face, the corners of
the mouth may droop, and a descent of the jowls can create folds
often referred to as "marionette lines." Furthermore, jowls form
when the cheeks sag around a fixed point along the jaw where the
facial muscles attach to the jawbone.
[0010] Various injectables have been used for restoring tissue loss
in the face. Since the 1980s, injectable collagen has been used as
a soft-tissue filler to fill wrinkles, lines, and scars on the
face. Collagen is a naturally occurring protein that supports
various parts of the body including skin, tendons, and ligaments.
Fat injections have also been used to add volume, fill wrinkles and
lines, and enhance the lips. Fat injections involve taking fat from
one part of a patient's body (typically the abdomen, thighs, or
buttocks) and reinjecting it beneath the facial skin. Botulinum
toxins, which were first approved for the treatment of neck spasms,
cranial nerve disorders, and eye spasms, have also been used
"off-label" for cosmetic purposes. With the recent FDA approval of
Botox for cosmetic use in the glabellar region, the drug is
becoming widely used for the temporary treatment of dynamic lines.
In contrast to fillers, the botulinum toxin is injected into facial
muscles, temporarily blocking nerve impulses and relaxing the
muscles to smooth so-called "worry lines."
[0011] Hyaluronic acid is one of most commonly used cosmetic dermal
fillers. Hyaluronic acid is a linear polysaccharide that exists
naturally in all living organisms, and is a universal component of
the extra-cellular spaces of body tissues. The identical structure
of hyaluronic acid in all species and tissues makes this
polysaccharide an ideal substance for use as a bio-material in
health and medicine. Hyaluronic acid is present in many places in
the human body. It gives volume to the skin, shape to the eyes, and
elasticity to the joints. The highest concentrations of hyaluronic
acid are found in connective tissues, and most of the hyaluronic
acid produced by the human body (about 56%) is found in the
skin.
[0012] Various forms of hyaluronic acid are provided commercially
by a number of manufacturers. The most commonly used hyaluronic
acid is a non-animal stabilized hyaluronic acid (NASHA),
distributed in a clear gel form and produced by bacterial
fermentation using streptococci bacteria. Different from
animal-derived hyaluronic acid, the non-animal-derived hyaluronic
acid is free from animal proteins. This limits the risk of
animal-based disease transmission or the development of an allergic
response. The most known non-animal stabilized hyaluronic acid is
manufactured by Q-med AB of Seminariegatan, Uppsala, Sweden and
commercially available under the tradename Restylane.RTM.. Since
its commercialization in 1996, it is estimated that over 2,500,000
treatments have been carried out worldwide. Other non-animal
stabilized hyaluronic acid products include Perlane.RTM. from
Q-med, which has larger particles than Restylane.RTM., and
Captique.TM. from Genzyme Corporation. Another commonly used filler
is a hyaluronic acid derivative manufactured by Genzyme Corporation
and commercially available under the tradename Hylaform Plus.
Hylaform Plus is a sterile, nonpyrogenic, viscoelastic, clear,
colorless, transparent gel implant composed of cross-linked
molecules of hyaluronan. Although hyaluronic acid and its
derivatives are the most commonly used dermal fillers, they have
limited long-term viability. The material must be reinjected
periodically, typically every 4 to 12 months, due to hyaluronan
metabolism in the body.
[0013] To increase the longevity of dermal fillers, high molecular
weight formulations are being developed. However, increasing
molecular weights result in higher and higher viscosities. The
higher the viscosity, the more difficult it is to inject the
desired amount of dermal filler into the desired location, or to
extract any excess. In addition, because the dermal filler must be
injected within the existing skin layers, and there is minimal
ability to create a pocket for the filler to reside in, it is
difficult to manipulate high molecular weight fillers within
existing skin tissue to achieve the desired cosmetic effect. Also,
once injected, high molecular weight dermal fillers may shift to a
different location and create an undesirable cosmetic defect.
Current methods which seek to use a lysing agent to remove excess
or unwanted filler do not provide much differential action with
respect to native tissue, causing damage to adjacent tissues and
substantially increasing the risk of a poor aesthetic outcome.
[0014] Ultrasonic energy can be used to shear-thin highly viscous
materials, and the applicants have found that ultrasonic energy can
successfully be used to shear-thin collagen-based dermal fillers.
The energy can be applied via direct contact ultrasound (at
frequencies of 20-200 kHz) or via high intensity, focused, field
effect ultrasound or "HIFU" (at frequencies of 50 kHz-20 MHz).
Since a non-thermal shearing action will be desired from the HIFU
source, the frequencies of interest will dip below the traditional
lower frequency limit of high frequency medical ultrasound, 500
kHz, to at least 100 kHz. The lower frequency limit will typically
be defined by the desired resolution of the focal point for
treatment. Ultrasonic energy can also be used to undermine or
dissect tissue, to release folds, or to create pockets within
tissue.
[0015] The requirements and construction of devices for delivering
contact ultrasound and HIFU will be different. Contact devices must
come into direct contact with a filler in order for an ultrasonic
element to shear-thin the filler material. HIFU devices, on the
other hand, focus field effect ultrasound so as to shear-thin the
filler material without direct contact between the ultrasound
radiator and the filler. However, readily known devices are
deficient in that contact devices are generally designed for the
macroscopic coagulation or ablation of tissue surfaces, while HIFU
devices are generally designed for the image-guided hyperthermic,
coagulative, or cavitation-induced destruction of tissue at depth.
Accordingly, improved ultrasonic apparatuses that are safe and
effective for non-thermal, shallow depth dermatological treatments
are required. In addition, methods for manipulating high molecular
weight, high viscosity dermal fillers and shallow facial tissues
are desired.
SUMMARY
[0016] A first embodiment of an ultrasonic surgical apparatus
includes a medical ultrasound handpiece having a distal end and an
ultrasound radiator mounted proximally from the distal end. The
ultrasound radiator is configured to create a beam of ultrasound
energy having a focal point at a predetermined distance from the
ultrasound radiator in the direction of the distal end, and has at
least one monolithic ultrasound source with a focused emitting
surface or at least one array ultrasound source configured as an
electronically focusable array. The first embodiment also includes
a guide member for placement around a facial feature, whereupon the
ultrasound handpiece is slidably engaged with the guide member to
position the focal point within the skin.
[0017] A method of using the device of the first embodiment
includes the steps of: injecting a dermal filler into the dermis of
a facial feature; placing the distal guide member of the first
embodiment on the surface of the skin so as to surround the facial
feature; applying an acoustic gel to the skin over the facial
feature; engaging the distal end of the ultrasound handpiece of the
first embodiment with the emplaced guide member; and slidably
translating the ultrasound handpiece upon the emplaced guide member
to position the focal point of the ultrasound radiator within the
injected dermal filler, then subsequently powering the ultrasound
radiator to shear-thin the dermal filler.
[0018] A second embodiment of an ultrasonic surgical apparatus
includes a medical ultrasound handpiece having a distal end, a
distal rolling member for placement over a facial feature, and a
ultrasound radiator mounted proximally from the distal end. The
ultrasound radiator is configured to create a beam of ultrasound
energy having a focal point at a predetermined distance from the
ultrasound radiator in the direction of the distal end, and has at
least one monolithic ultrasound source with a focused emitting
surface or at least one array ultrasound source configured as an
electronically focusable array. In certain expressions of the
embodiment, the distal rolling member is externally coupled to the
ultrasound radiator through an acoustic coupling medium generally
contained within the medical ultrasound handpiece. In other
expressions of the embodiment, the distal rolling member is
internally coupled to the focusing ultrasound radiator, which is
contained within the distal rolling member.
[0019] A method of using the device of the second embodiment
includes the steps of: injecting a dermal filler into the dermis of
the facial feature; placing the distal rolling member of the device
of the second embodiment on the surface of the skin over the facial
feature; applying an acoustic gel to the skin over the facial
feature; and rollingly translating the distal rolling member over
the skin to position the focal point of the focusing ultrasound
radiator within the injected dermal filler, then subsequently
powering the ultrasound radiator to shear-thin the dermal
filler.
[0020] A third embodiment of an ultrasonic surgical apparatus
includes a medical ultrasound handpiece assembly having an
ultrasound transducer and an end effector coupled to the ultrasound
transducer. The end effector has, in order, a distal probe tip, a
probe neck, a probe dilation region, and ultrasonically active
shaft, with the shaft being coaxially held within an ultrasonically
inactive probe sheath. The probe dilation region is configured to
have an average outside diameter that is equal to or greater than
the average outside diameter of the probe tip and the average
outside diameter of the probe neck. The probe sheath is configured
to have an outside diameter that is approximately equal to the
outside diameter of the probe dilation region so as to create a
uniform junction between the probe sheath and the probe dilation
region. In certain expressions of the embodiment, the junction may
be tight between the probe sheath and the probe dilation region. In
other expressions of the embodiment, the junction may be loose but
self-cleaning.
[0021] A method of using the device of the third embodiment
includes the steps of: injecting a dermal filler into a facial
feature; inserting at least the distal probe tip of the device of
the third embodiment beneath the surface of the skin and into the
injected dermal filler; powering the ultrasound transducer to
operate the probe tip; and inserting at least the distal probe tip
into the injected dermal filler. A preferred method further
includes the step, following the powering step, of inserting the
probe dilation region beneath the surface of the skin to protect
the surface of the skin from unintended contact with ultrasonically
active portions of the probe.
[0022] A fourth embodiment of an ultrasound surgical apparatus
includes a medical ultrasound handpiece assembly having an
ultrasound transducer and an end effector coupled to the ultrasound
transducer. The end effector has, in order, a distal probe tip, a
probe neck, and an ultrasonically active shaft, with the shaft
coaxially being held within an ultrasonically inactive probe
sheath. The probe sheath is configured such that the distal end of
the probe sheath is slidably operable to both cover and expose at
least the probe tip. In certain expressions of the embodiment, the
distal end of the probe sheath is configured to slidably retract
when the probe sheath experiences a certain longitudinal
resistance. In other expressions of the embodiment, the proximal
end of the probe sheath is coupled to an adjustment mechanism for
slidably retracting and extending the distal end of the probe
sheath.
[0023] A method of using the device of the fourth embodiment
includes the steps of: inserting at least the distal probe tip of
the device of the fourth embodiment beneath the surface of the
skin; powering the ultrasound transducer to operate the distal
probe tip; inserting the distal end of the ultrasonically inactive
probe sheath beneath the surface of the skin while the ultrasound
transducer is powered; advancing the probe tip while the ultrasound
transducer is powered; and retracting the distal end of the probe
sheath to expose a greater length of the distal probe tip. A
preferred method for use with devices including an adjustment
mechanism further includes the step, following the insertion of the
distal probe tip, of inserting the distal end of the probe sheath
beneath the surface of the skin to protect the surface of the skin
from unintended contact with the ultrasonically active portions of
the probe. The method may be applied to injected dermal fillers and
blepharoplasty.
[0024] A fifth embodiment of an ultrasonic core for an ultrasound
surgical apparatus includes a transducer structure affixed to a
longitudinally elongated, generally planar, single crystal or
polycrystalline material waveguide. The waveguide has, in order, a
first resonator or proximal end portion, a transduction portion,
and a second resonator. The fifth embodiment may also include a
single or polycrystalline material end effector portion
monolithically or resonantly coupled to the waveguide to serve at
least as an ultrasonically active shaft.
[0025] Other aspects of the disclosed ultrasonic apparatus and
method for shear-thinning dermal fillers will become apparent from
the following description, the accompanying drawings, and the
appended claims. Several benefits and advantages are obtained from
one or more of the expressions of the embodiments of the invention.
In one example, the ultrasound apparatuses disclosed herein help
enable the economic manipulation of high molecular weight, high
viscosity dermal fillers in vivo. In another example, the
ultrasound apparatuses disclosed herein provide for the ultrasonic
manipulation of tissues within specific layers or at specific
depths while shielding overlying tissue. In yet another example,
the methods of shear-thinning dermal filler materials disclosed
herein help enable the in vivo reshaping of previously injected
dermal fillers. In other examples, the devices and methods are used
in microsurgical applications such as blepharoplasty. In general,
contact and non-contact devices are disclosed which can be
beneficially used to instantaneously decrease the viscosity of a
dermal filler material without permanently decreasing the molecular
weight of the material and/or the ability of the material to `gel,`
thereby increasing the long-term viability of injectable dermal
filler treatments. Features of the devices allowing for the finely
controlled application of ultrasound near or within sensitive soft
tissues, such as the epidermis and dermis, are of course useful in
other types of dermatological and microsurgical procedures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1 is a cross-sectional side view of a medical
ultrasound handpiece and guide member.
[0027] FIG. 2 is a plan view of a guide member, with a distal end
of a medical ultrasound handpiece outlined in phantom lines for
context.
[0028] FIG. 3 is a cross-sectional side view of the guide member of
FIG. 2, with a medical ultrasound handpiece outlined in phantom
lines for context.
[0029] FIG. 4 is a schematic top view of a guide member with a
passive wire loop. A medical ultrasound handpiece with an active
wire loop is shown in phantom lines for sake of clarity.
[0030] FIGS. 5 and 6 are schematic side views of medical ultrasound
handpieces.
[0031] FIG. 7 is a perspective, cut-away view of a medical
ultrasound handpiece with a distal rolling member or "ball."
Obscured portions of the ball are outlined in phantom lines, and
mounting structure, electrical connections, etc., have been
omitted.
[0032] FIG. 8 is a schematic, side detail view of a distal end and
distal rolling member.
[0033] FIG. 9 is a front view of a medical ultrasound handpiece, as
well as multiple rings for attachment to a distal rolling member or
"ball."
[0034] FIG. 10 is a side view of the "ball" of FIG. 9, as well as
multiple rings for attachment to the "ball."
[0035] FIG. 11 is a partially exploded, cross-sectional front view
of the "ball" of FIGS. 9 and 10.
[0036] FIG. 12 is a cross-sectional side view of the "ball" of
FIGS. 9-11.
[0037] FIG. 13 is a schematic side view of a transducer structure
in a medical ultrasound handpiece.
[0038] FIG. 14 is a cross-sectional side view of various end
effector probe constructions.
[0039] FIG. 15 is a side view of a distal probe tip.
[0040] FIGS. 16 and 17 are front views of the distal probe tips
shown in FIG. 14.
[0041] FIGS. 18 and 20 are perspective views of probe necks
(including blunt distal probe tips). FIGS. 19 and 21 are
cross-sectional end views of the respective probe necks.
[0042] FIGS. 22-24 are schematic side views of aspects of a medical
hand piece assembly relating to fluid communications
configurations.
[0043] FIG. 25 is a cut-away side view of a probe sheath retraction
mechanism.
[0044] FIG. 26 combines an edge view ("Before") and cross-sectional
top view ("After") to illustrate another probe sheath retraction
mechanism.
[0045] FIGS. 27 and 28 are a schematic side views of medical hand
piece assemblies relating to operation of the probe sheath.
[0046] FIGS. 29-31 are perspective views of varying probe
configurations.
[0047] FIG. 32 is a cross-sectional view of a probe configuration
including a cannula.
[0048] FIG. 33 is schematic view with side and edge views of an
ultrasonic core.
[0049] FIG. 34 is a cross-sectional edge view of exemplary
laminated ultrasonic core constructions.
[0050] FIG. 35 is a cross-sectional side view of exemplary end
effector portions.
[0051] FIGS. 36 and 37 are schematic side views of exemplary second
resonator configurations.
[0052] FIG. 38 is a perspective view of an exemplary second
resonator configuration, with a resonant transverse mode of
vibration shown in an exaggerated physical representation in
phantom lines (top side only).
[0053] FIGS. 39 and 40 are schematic side views of exemplary second
resonator configurations.
[0054] FIG. 41 is a schematic side view of exemplary second
resonator configurations including a transducer gain portion.
[0055] FIG. 42 is a schematic end view of exemplary
transducer-to-waveguide bond and power structures.
[0056] FIG. 43 is a schematic detail view of a waveguide electrical
contact (Note: structure of transduction portion 594 is exemplary
only).
[0057] FIG. 44 is a schematic perspective view of a laminated
waveguide with internal transducer. First resonator 592 is omitted
but partially outlined in phantom lines for context.
[0058] FIG. 45 is a schematic perspective view of a transduction
portion, with first and second resonators omitted.
[0059] FIG. 46 is a side view of a transduction portion of a
waveguide with the position of a transducer shown in phantom lines
for context.
[0060] FIG. 47 is a cross-sectional edge view of the waveguide of
FIG. 46.
[0061] FIG. 48 is an exploded side view of a transduction portion
of a waveguide.
[0062] FIG. 49 is a cross-sectional edge view of the waveguide of
FIG. 48, including a plate and compressive fastener.
[0063] FIG. 50 is a cross-sectional edge view of a device similar
to that shown in FIG. 48, but with symmetrically disposed
transducers, plates, and a compressive fastener.
[0064] FIGS. 51A and 51B are perspective views of a transduction
portion of a waveguide before and after the application of metal
band.
[0065] FIG. 52A is an edge view of a waveguide, with braze 601
exaggerated for visual clarity.
[0066] FIG. 52B is a diagram of a process for assembling an
ultrasonic core with post-assembly poling.
[0067] FIGS. 52C and 52D are schematic perspective views of
ultrasonic core transducer structures amenable to post-assembly
poling.
[0068] FIG. 53A is an exploded perspective view of a transduction
portion of a waveguide including a carrier-transducer
subassembly.
[0069] FIGS. 53B and 53C are detailed edge and side views,
respectively, of a carrier-transducer subassembly amenable to
post-subassembly poling.
[0070] FIG. 53D is exploded perspective view of a transduction
portion of a waveguide including the carrier-transducer subassembly
of FIGS. 53B and 53C.
[0071] FIG. 53E is a diagram of a process for assembling a
carrier-transducer subassembly with post-assembly poling.
[0072] FIGS. 53F and 53G are partially exploded perspective views
of magnetostrictive ultrasonic cores for use with a surrounding and
encased coil.
[0073] FIGS. 54 and 55 are schematic edge views of ultrasonic core
transducer structures.
[0074] FIG. 56 is a schematic side view of an ultrasound core
transducer structure.
[0075] FIG. 57A is a side view of an ultrasound core configured for
surface mounting of a transducer 602 on a transduction portion
594.
[0076] FIG. 57B is an edge view, with detail inset, of an
ultrasound transducer electrode structure and transduction portion
electrical contact 612. Transduction portion 594 of waveguide 590
is shown in phantom lines for sake of clarity.
[0077] FIG. 58A is a schematic side view of an ultrasound
transducer and waveguide configured for surface mount assembly.
[0078] FIG. 58B is a schematic edge view of a waveguide with a
surface mounted ultrasound transducer.
[0079] FIG. 59A is a schematic side view of an ultrasound
transducer and waveguide configured for surface mount assembly.
[0080] FIG. 59B is a perspective view of the an ultrasound
transducer and waveguide of FIG. 59A.
[0081] FIG. 60 is an exploded side view of a first resonator of a
waveguide.
[0082] FIG. 61 is a cross-sectional edge view of the waveguide of
FIG. 60, including a compressive fastener.
[0083] FIG. 62 is an edge view of a first resonator, with inset
detail of a toothed connection.
[0084] FIG. 63 is a schematic side view of a first resonator and
abutting end mass, with interconnecting lumen shown in phantom
lines for context
[0085] FIG. 64 is a cross-sectional edge view of the first
resonator, end mass, and interconnecting lumen structure of FIG.
63.
[0086] FIG. 65 is a schematic side view of an instrument employing
a proximally spaced-apart and fixed end mass, with interconnecting
lumen shown in phantom lines for context.
[0087] FIG. 66 is a cross-sectional edge view of the instrument of
FIG. 65.
[0088] FIG. 67 is a schematic edge view of an exemplary instrument
including the ultrasonic core of the fifth embodiment.
[0089] FIG. 68 is a perspective view of an exemplary ultrasonic
core for an ultrasonic surgical instrument including a composite
distal tip.
[0090] FIG. 69A is an exploded perspective view of one construction
of the composite distal tip of FIG. 68. The exterior of the top
layer of the end effector/waveguide is shown in phantom lines for
sake of clarity.
[0091] FIG. 69B is an exploded perspective view of another
construction of the composite distal tip of FIG. 68. The exterior
of the top layer of the end effector/waveguide is shown in phantom
lines for sake of clarity.
[0092] FIG. 69C is a perspective view of yet another construction
of the composite distal tip of FIG. 68. A portion of the top layer
of the end effector/waveguide is shown in phantom lines for sake of
clarity.
[0093] FIG. 70 is a cross sectional side view of an exemplary
ultrasonic core for an ultrasonic surgical instrument.
[0094] FIG. 71 is a schematic side view of an ultrasonic core
construction.
[0095] FIGS. 72 and 73 are plots from ANOVA analyses of a DOE model
of an exemplary ultrasonic core, illustrating the component effect
of transducer length upon gain and acoustic impedance,
respectively, of the modeled construction.
[0096] FIGS. 74 and 75 are plots from parametric analyses of the
DOE model, illustrating the effect of modal frequency separation
upon acoustic impedance and phase peak, respectively, in the
modeled construction.
[0097] FIG. 76 is a plot from a parametric analyses of the DOE
model, illustrating the effect of distal margin between a distal
end of a transducer and a proximal end of the distal resonator upon
the drive power of a component end effector.
DETAILED DESCRIPTION
[0098] Before explaining the several embodiments of the present
invention in detail, it should be noted that the expressions and
embodiments are not limited in their application or use to the
details of construction and arrangement of parts and steps
illustrated in the accompanying drawings and description. The
illustrative expressions and embodiments may be implemented or
incorporated in other expressions, 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 embodiments of the present invention for the
convenience of the reader, and are not for the purpose of limiting
the invention.
[0099] It is further understood that any one or more of the
following-described expressions, embodiments, examples, etc. may be
combined with any one or more of the other following-described
expressions, embodiments, examples, etc. Such modifications and
variations are intended to be included within the scope of the
claims.
[0100] A first embodiment of the invention is shown in FIGS. 1-4.
The first embodiment includes a medical ultrasound handpiece 100
having a distal end 102 and a focusing ultrasound radiator 104
mounted proximally from the distal end. The ultrasound radiator 104
is configured to create a beam of ultrasound energy having a focal
point, f at a predetermined distance, d, from the ultrasound
radiator 104 in the direction of the distal end 102. This
configuration is used to focus ultrasound energy within a facial
feature 10 having a pocket of dermal filler 12 implanted in the
dermis (including the dermal junctions) to cause shear-thinning of
the dermal filler 12. The ultrasound radiator 104 has at least one
monolithic source with a focused emitting surface, at least one
array source configured as an electronically focusable array, or a
combination of such ultrasound sources. Examples of array sources
are disclosed in PCT Application Publication No. WO/2006/082573,
the entire contents of which are incorporated herein by
reference.
[0101] Because a focused monolithic source generates a shear which
is strongest at the perimeter of the generated acoustic wave
profile, additional sources may configured so that the beam axes,
B.sub.1 through B.sub.n, of the sources generally converge upon the
focal point f to enhance the ability of device to create shear
proximate the focal point. A configuration of multiple ultrasound
sources in a non-overlapping, convergingly focused assembly, as
illustrated in FIG. 6, can enable this edge effect to be
accentuated by varying the relative phases and intensities of the
emitted ultrasound energy. However, this advantage is limited as a
matter of practicality to devices which include a small plurality
of focused monolithic sources, since a large array of transducers
operated in this manner approximates the function of a single array
source, i.e., multiplicity has rapidly diminishing returns in the
face of increasing customization and complexity. The ultrasound
radiator 104 is preferably configured to create both longitudinal
and transverse acoustic waves, and should be coupled to the skin
through an acoustic gel 16, which serves to improve coupling to the
skin 14 and to improve the lubricity of the distal end 102 for
movement over the skin 14. The use of acoustic gels and the
dispensing of such gels are known in the art. See, for example,
U.S. Pat. App. Publication No. 2008/0027328. The ultrasound
radiator 104 should emit about 1 to 20 watts of effective power,
with the heat generated thereby being dissipated or removed via
thermal radiation, thermal conduction, or thermal mass or
capacitance in order to prevent injury during continuous acoustic
excitation. The acoustic gel 16 may be used to assist in such heat
dissipation or removal.
[0102] It is important to note that if energy delivery is focused
too deeply, then vital nerves and/or muscles may be damaged.
However, if energy delivery is focused too shallowly, then the
epidermis may be burned. The first embodiment also includes a guide
member 106 for placement around the facial feature 10. The guide
member 106 serves to define an area for treatment and to protect
the skin 14 around that area from diffuse ultrasound energy near
the focal point (or erroneous manipulation of the handpiece). The
predetermined distance d may generally be adjusted electrically
within an array ultrasound source, mechanically by varying the
thickness of the guide member 106 (or adding additional members
106), and/or mechanically by varying the position of the focusing
ultrasound radiator 104 with respect to the distal end 102 with a
mechanical positioning system. However, guide member 106 may also
serve to resist localized distortion of the skin 14 during
application of the handpiece 100 to ensure that the predetermined
distance d falls within the dermis (including the dermal
junctions), as opposed to the epidermis or hypodermis, during a
treatment procedure so as to minimize the need to adjust the
distance d during a procedure.
[0103] In a first expression of the first embodiment, shown in FIG.
1, the distal guide member 106 may be a locating ring 108 to be
positioned around the facial feature 10. In one construction, the
locating ring 108 may be adhered to the surface of the skin 14
surrounding the facial feature 10 by an adhesive backing 109. In
another construction, the locating ring 108 may be adhered to the
surface of the skin 14 surrounding the facial feature 10 by a
partial vacuum applied by a vacuum port 110 connected to a chamber
112 defined within locating ring 108 (and between the medical
ultrasound handpiece 100 and the skin 14). In these or other
constructions, the chamber 112 may be supplied with an acoustic gel
16 through the vacuum port 110, or through a separate fluid port
114. In one exemplary construction, the locating ring 108 is
constructed from a flexible foam sheet. The foam is preferably
flexible to conform to the face but essentially incompressible
under typical loads (up to 5 psi) in order to maintain its shape
thickness. The foam is preferably open-celled to provide a path for
vacuum and to enhance acoustic protection around the periphery of
the chamber 112. Locating ring 108 may define a substantially
annular periphery for chamber 112, but may also or alternately be
cut by the user to define the periphery of an area for treatment.
The distal end 102 is slidably engaged with the locating ring 108
to position the focal point f within the skin 14.
[0104] In a second expression of the first embodiment, shown in
FIGS. 2 and 3, the distal guide member 106 may be a locating base
118 with a slidable, interlocking shuttle member 120. In one
construction, the locating base 118 may be adhered to the surface
of the skin 14 surrounding the facial feature 10 by an adhesive
backing 119. The shuttle member 120 is configured to receive the
distal end 102 of the medical ultrasound handpiece 100, which may
serve as or provide a repositionable foot 122. The repositionable
foot 122 may treat larger areas or long tracks by enabling the
sequential treatment of a series of contiguous `spots` within the
facial feature 10. The repositionable foot 122 may be slidably
repositioned within the locating base 118 by the user or under
computer control. In one construction, the repositionable foot 122
may be detachable from the medical ultrasound handpiece 100. In one
variation, the repositionable foot 122 may be a single use,
consumable part. In another variation, the repositionable foot 122
may be a reusable, sterilizable part. In an exemplary construction,
one of a plurality of repositionable feet 122 having varying
thicknesses may be detachably affixed to the ultrasound handpiece
100 to mechanically vary the position of the focusing ultrasound
radiator 104 with respect to the distal end 102, and thus the depth
at which the predetermined distance d is found within the skin 14.
In another exemplary construction, one of a plurality of
repositionable feet 122 having varying areal dimensions may be
detachably affixed to the ultrasound handpiece 100 to control the
application of diffuse ultrasound energy near the focal point to
the skin 14. The distal end 102 is slidably engaged with the
locating base 118, via the shuttle 120, to position the focal point
f within the skin 14.
[0105] In a third expression of the first embodiment, the medical
ultrasound handpiece 100 includes a registration system 124
configured to monitor the location and/or track of the focal point
f with respect to the distal guide member 106. Registration and
tracking systems may include: software for tracking instrument
position; electrically resonant rings, defined by a passive wire
loop 125 (with a load such as a resistor and capacitor connected in
series) affixed to the guide member 106 and an active wire loop 126
excited by a radio frequency element 127 mounted in the ultrasound
handpiece 100, for proximity warning; magnetic coupling between the
ultrasound handpiece 100 and the guide member 106, established in
part by loading the guide member 106 with either a high
susceptibility material or a permanent magnet material, for
proximity warning; an electrical conductivity sensor (not shown),
configured to detect the different electrical conductivities of the
guide member 106 and the skin 14, for perimeter violation warnings;
or a polarization sensor (not shown), configured to indirectly
measure the differential electrical susceptibility of tissue prior
to and after ultrasonic treatment, for indirectly tracking
instrument position (more precisely, prior treatment positions).
The guide member 106 may also be designed to have a very different
electrical susceptibility so that the polarization sensor may be
used for perimeter violation warnings. The delivery of ultrasound
energy may be manually or automatically controlled based on the
residence time of the ultrasound handpiece 100 over any particular
portion of the facial feature 10 as it is moved back and forth
across the surface of the skin 14 within the guide member 106. The
delivery of ultrasound energy may also be automatically controlled
based on measurements of skin characteristics during ultrasound
treatment, such as the electrical susceptibility of pre-treatment
and post-treatment tissue during the course of a procedure.
[0106] In a method of using the expressions of the first
embodiment, a dermal filler 12 is injected into the dermis of the
facial feature 10, and a distal guide member 106 is placed on the
surface of the skin 14 so as to surround the facial feature 10. The
dermal filler 12 may be injected before or after placement of the
guide member 106. The medical ultrasound handpiece 100 is placed on
the guide member 106, and an acoustic gel 16 is applied to the skin
14 over the facial feature 10. The acoustic gel 16 may be applied
before or after placement of the ultrasound handpiece 100 on the
guide member 106, depending upon the source of the gel, e.g.,
separate applicator or application via a handpiece port 110 or 114.
The distal end 102 of the ultrasound handpiece 100 is engaged with
the guide member 106, and slidably translated upon the guide member
106 to position the focal point f of the focusing ultrasound
radiator 104 within the injected dermal filler 12, whereupon the
ultrasound radiator 104 is powered to shear-thin the dermal filler
12. In one variation of the method, the ultrasound handpiece 100 is
removed from engagement with the guide member 106 and the dermal
filler 12 is manipulated from the surface of the skin 14 while in a
shear-thinned state. In another variation of the method, both the
ultrasound handpiece 100 and the guide member 106 are removed from
the skin 14, and the dermal filler 12 is manipulated from the
surface of the skin 14 while in a shear-thinned state.
[0107] In an implementation of the method, the skin 14 of the
facial feature 10 is pulled into the chamber 112 defined by the
distal guide member 106 by a partial vacuum. This permits more
robust definition of the skin surface plane in the presence of
wrinkles, and serves to accurately position the surface of the skin
14 with respect to the focusing ultrasound radiator 104 and focal
point f The focusing ultrasound radiator 104 is subsequently
powered to shear-thin the injected dermal filler 12. In another
implementation of the method, the skin 14 of the facial feature 10
is placed into tension, and the distal guide member is subsequently
adhered onto the tensioned surface of the skin 14. This similarly
improves the definition of the skin surface plane, as well as the
accuracy of the positioning of the surface of the skin 14 with
respect to the ultrasound radiator 104. The ultrasound radiator 104
is subsequently powered to shear-thin the injected dermal filler
12.
[0108] A second embodiment of the invention is shown in FIGS. 5-8.
The second embodiment includes a medical ultrasound handpiece 200
having a distal end 202, a distal rolling member 206 for placement
over a facial feature 10, and a focusing ultrasound radiator 204
mounted proximally from the distal end 202. The ultrasound radiator
204 is configured to create a beam of ultrasound energy having a
focal point, f, at a predetermined distance, d, as otherwise
described in the context of the first embodiment.
[0109] In a first expression of the second embodiment, shown in
FIGS. 5 and 6, the distal rolling member 206 may be a ring of
bearings 208, e.g., roller bearings or ball bearings, disposed at
the distal end 202 to facilitate motion across the surface of the
skin 14. The distal end 202 of the medical ultrasound handpiece 200
includes an acoustic head 216 coupled to the focusing ultrasound
radiator 204 through an internal acoustic coupling medium 218 such
as a fluid or gel. The acoustic head 216 is preferably constructed
from polysulfone, REXOLITE.RTM. (a thermoset material produced by
crosslinking polystyrene with divinylbenzene, marketed by C-LEC
Plastics of Willingboro, N.J.) or "LOTEN" (marketed by Sigma
Transducers of Kennewick Wash.). Regardless of the material used,
the acoustic impedance of the acoustic head 216 should be within a
factor of 5 of the acoustic impedance of water, 1.5.times.10.sup.6
kg/m.sup.2*sec. Additional construction details intended to
minimize the reflection of ultrasound energy are known within the
art. See, e.g., U.S. Pat. Nos. 6,082,180 and 6,666,825. In one
construction, the acoustic head 216 includes a separable
interfacial boot 220 configured to shield the acoustic head 216
from contact with the surface of the skin 14. The interfacial boot
220 is preferably constructed from silicone, since it provides a
reasonable impedance match and is biocompatible for patient
contact. Functionally, silicone may also be stretched across the
acoustic head 216 by the user for a tight, gapless fit. The
interfacial boot 220 may be treated as a single use, consumable
part or a reusable, sterilizable part. In another construction, a
partial vacuum may be applied to the skin 14 proximate the distal
end 202 by a vacuum manifold 212 to enhance contact between the
acoustic head 216 and the skin 14. In this or other constructions,
the distal end 202 may be supplied with an acoustic gel 16 through
the vacuum manifold 212 or through a fluid port 214 disposed
proximate the acoustic head 216. In one variation, the ultrasound
handpiece 200 may include both a vacuum manifold 212 and a fluid
port 214, with the fluid port 214 being located circumferentially
oppositely from a vacuum source 210 within the vacuum manifold
212.
[0110] In a second expression of the second embodiment, shown in
FIGS. 7 and 8, the distal rolling member 206 may be a cylinder or a
generally smoothly curved volume of rotation 228, .e.g., truncated
ellipsoids, semi-ellipsoids, spheres, and the like, hereinafter
generalized under the term "ball," disposed at the distal end 202.
The ball 228 is externally coupled to the focusing ultrasound
radiator 204 through an acoustic coupling medium 218 generally
contained within the medical ultrasound handpiece 200. In one
construction, the ball 228 may be formed from an acoustically
transparent material. In another construction, the surfaces of the
ball may be internally coupled through an acoustic coupling fluid
or gel 226 contained within the ball 228. In one construction,
acoustic gel 16 may be dispensed from within the ultrasound
handpiece 200 as a coating on the surface of the ball 228 for use
as a lubricant and acoustic coupling medium between the exposed
surface of the ball 228 and the surface of the skin 14. In another
construction, acoustic gel 16 may be dispensed onto the ball 228
through a separate fluid port 214 at the distal end 202.
[0111] In a third expression of the second embodiment, shown in
FIGS. 9-12, the distal rolling member 206 may also be a ball 228.
However, the ball 228 may be mounted to the medical ultrasound
handpiece 200 for rotation about a predetermined axis, R. The ball
228 in fact serves in part as the distal end 202 of the medical
ultrasound handpiece 200, with the focusing ultrasound radiator 204
being located within the ball 228 and the ball 228 being internally
coupled to the ultrasound radiator 204 through an acoustic coupling
fluid 226 contained within the ball 228. The ball 228 may include a
stator 230 extending between the axial ends, R.sub.1 and R.sub.2,
of the axis of rotation of the ball 228, one or more seals 232
disposed about the interface between the stator 230 and the axial
ends R.sub.1 and R.sub.2 and, optionally, bearings 234 disposed at
the interface between the stator 230 and the axial ends R.sub.1 and
R.sub.2. The ultrasound radiator 204 is mounted to the stator 230,
which may be fixed or user-adjustably fixed in orientation with
respect to a handle portion 250 of the ultrasound handpiece 200. In
one construction, the stator is fixed in orientation with respect
to the handle by a pin-and-plug connection 236 between the stator
230 and the handle portion 250. In another construction, the stator
is user-adjustably fixed in orientation with respect to the handle
portion 250 by a pin-and-plug connection 236 in which the pin and
plug (illustrated for exemplary purposes as rectangular projections
and voids) may be conformably interconnected together in any of a
plurality of positions. In one variation, the handle portion 250
may be a single use, consumable part. In another variation, the
handle portion 250 may be a reusable, sterilizable part.
[0112] In an implementation of the third expression, a ring 240 of
material may be removably attached to the ball 228. The ring 240
serves as a rotating patient-contact surface. In one variation, the
ring 240 may be a single use, consumable part. In another
variation, the ring 240 may be a reusable, sterilizable part. In
one exemplary construction, one of a plurality of rings 240 having
varying material thicknesses may be removably attached to the ball
228 to mechanically vary the position of the focusing ultrasound
radiator 204 with respect to the distal end 202, and thus the depth
at which the predetermined distance d is found within the skin 14.
In another exemplary construction, one of a plurality of rings 240
having varying widths may be removably attached to the ball 228 to
mechanically limit the transmission of diffuse ultrasound energy
from the ball 228 to portions of the skin 14 adjacent to a linear
facial feature 10.
[0113] In a method of using the expressions of the second
embodiment, a dermal filler 12 is injected into the dermis of the
facial feature 10, and the distal rolling member 206 is placed on
the surface of the skin 14 over the facial feature 10. An acoustic
gel 16 may be applied to the skin 14 over the facial feature 10
before or after placement of the distal rolling member 206 on the
skin 14, depending upon the source of the acoustic gel, .e.g.,
separate applicator, application via a handpiece port 214, or
transfer from the surface of the distal rolling member 206. The
distal rolling member 206 is rollingly translated over the skin 14
to position the focal point f of the focusing ultrasound radiator
204 within the injected dermal filler 12, whereupon the ultrasound
radiator 204 is powered to shear-thin the dermal filler 12. In one
variation of the method, ultrasound radiator 204 is depowered and
the distal rolling member 206 is further rollingly translated over
the skin 14 to manipulate the dermal filler from the surface of the
skin 14 while in a shear-thinned state. In another variation of the
method, the ultrasound handpiece 200 is removed, and the dermal
filler 12 is manipulated from the surface of the skin 14 while in a
shear-thinned state.
[0114] In an implementation of the method relating to the first
expression, the skin 14 of the facial feature 10 is pulled against
the acoustic head 216 by a partial vacuum. This permits more robust
definition of the skin surface plane in the presence of wrinkles,
and serves to accurately position the surface of the skin 14 with
respect to the focusing ultrasound radiator 204 and focal point f.
The focusing ultrasound radiator 204 is subsequently powered to
shear-thin the injected dermal filler 12.
[0115] A third embodiment of the invention is shown in FIGS. 13-21.
The third embodiment includes a medical ultrasound handpiece
assembly 300 having an ultrasound transducer 310, which may be
configured as a "Langevin stack." A "Langevin stack" generally
includes, in order, a first resonator or end-bell 312, a transducer
portion 314,and a second resonator or fore-bell 316, as well as
various ancillary components such as mounts, intermediate gain
stages, and the like which may be interposed between or mounted
around components 312, 314, and 316. Examples of ultrasonic
surgical instruments with this general configuration are disclosed
in U.S. Pat. Nos. 5,322,055 and 5,954,736. The transducer material
in the transducer portion 312 may be piezoelectric, but may
alternately be magnetostrictive, with a coils 318 and permanent
magnets 319 bracketing the transducer material, or
electrostrictive. Unless otherwise indicated, illustrations
omitting specialized transducer components as the aforementioned
coils and magnets should be understood as being generic, schematic
representations rather than limiting disclosures. The ultrasound
handpiece assembly 300 and ultrasound transducer 310 are coupled to
an end effector 320, as further described below. Examples of
medical ultrasound handpieces coupled to ultrasonic blades and
other surgical end effectors are disclosed in U.S. Pat. Nos.
6,278,218; 6,283,981; 6,309,400; 6,325,811; and 6,423,082, as well
as U.S. patent application Ser. No. 11/726,625, entitled
"Ultrasonic Surgical Instruments," filed on Mar. 22, 2007, and Ser.
No. 11/998,543, entitled "Ultrasonic Surgical Instrument Blades,"
filed on Nov. 30, 2007, all of which are incorporated by reference
herein. The ultrasonic transducer 310 and coupled end effector 320
are preferably an integral number of one-half system wavelengths
(n.lamda./2) in length. Unless otherwise indicated, illustrations
omitting routine components or illustrating partial structures
should be understood as being generic, schematic representations
rather than limiting disclosures.
[0116] The end effector 320 includes, in order, a distal probe tip
322, a probe neck 324, a proximal probe dilation region 326, and an
ultrasonically active shaft 328, with the shaft coaxially held
within an ultrasonically inactive probe sheath 330 and operatively
connected to the dilation region 326. The probe tip 322 is
generally rounded or paddle like, but may include a minor
distal-most blade portion 323 as described below. The dilation
region 326 is configured to have an average outside diameter that
is equal to or larger than the average outside diameter of the
probe tip 322, as well as that of probe neck 324. The probe sheath
330 is configured to have an outside diameter that is approximately
equal to the outside diameter of the dilation region 326. The
dilation region 326 is positioned at a proximal anti-node 332, and
is used to dilate the surface of the skin 14 so that the insertion
force associated inserting with the probe sheath 330 under an
initial perforation is minimized. A small initial hole, formed by
probe tip 322 or another instrument, followed by reversible
dilation appears to create the smallest long term hole in the
surface of the skin 14. The end effector should emit about 1 to 20
watts of effective power, but may have an instantaneous requirement
of up to about 30 watts during penetration of the skin 14. It is
important to note that while dermal filler procedures are a primary
application for such devices due to post-surgical cosmetic
concerns, the devices may also advantageously be scaled for use in
deep blunt dissection or sculpting procedures where the snagging of
the probe sheath 330 on tissue surfaces during an insertion
transition from the device blade/probe 322-326 to the probe sheath
330 is a concern.
[0117] In a first expression of the third embodiment, shown in FIG.
14, the probe dilation region 326 is located proximate the first
anti-node 332 proximal from the probe tip 322. In variations of the
first embodiment, the dilation region could be located proximate an
even more proximal anti-node. In one construction, the junction
between the dilation region 326 and the ultrasonically inactive
probe sheath 330 (when the end effector 320 is closed) may be
located at a node 334 proximal from the anti-node 332. This allows
for a very tight junction, which minimizes the likelihood of tissue
snagging at the interface between the dilation region 326 and the
probe sheath 330. In another construction, the junction between the
dilation region 326 and the probe sheath 330 (when the end effector
320 is closed) may be located at an anti-node 332. The junction is
preferably located at the same anti-node 332 as the transition
between the probe neck 324 and the dilation region 326. The latter
construction minimizes ultrasound gain impact, but necessitates a
gap between the dilation region 326 and the probe sheath 330. The
impact of the gap is somewhat mitigated because the ultrasonically
active shaft 328 and dilation region 326 are active at the junction
and will tend to self-clean.
[0118] In a second expression of the third embodiment, shown in
FIG. 15, the distal probe tip 322 may be sharpened to include a
distal-most mechanical blade portion 323 to facilitate rapid
penetration with minimal thermal spread. The mechanical blade
portion 323, while useful to enable rapid skin penetration, is
preferably minimized in size and extent to reduce the likelihood
that other tissue structures will be inadvertently damaged or
disrupted as the probe tip 322 is wanded back and forth to
shear-thin, blunt dissect tissue, and/or emulsify fat. Alternately,
in a third expression of the third embodiment, illustrated in the
topmost example in FIG. 14 and in an end view in FIG. 16, the probe
tip 322 may be dull. A dull tip allows the user to safely push the
probe tip 322 around in a blunt dissection mode, while initial
penetration and dilation of the skin are accomplished with an
unpowered needle or an obturator.
[0119] In a fourth expression of the third embodiment, shown in
FIGS. 17-21, the surface area of the distal probe tip 322 and/or
probe neck 324 is increased, while holding the cross-sectional area
of the part(s) constant, by configuring at least one of these
structures to have an undulating periphery in cross-section. This
improves power transfer efficiency into the dermal filler 12 and/or
other target tissues. In one construction, illustrated in the
bottommost example in FIG. 14 and in an end view in FIG. 17, the
probe tip 322 may have a high aspect ratio, with portions of the
probe tip 322 being wider than the width of the probe dilation
region 326. A high aspect ratio probe tip 322 allows for an
increase in the surface area-to-volume ratio of the device, but may
be inserted through, or itself create, a small incision-like slit
in the surface of the skin 14. Such constructions are intended to
be within the scope of devices where the dilation region 326 has an
average outside diameter that is equal to or larger than the
average outside diameter of the probe tip 322. In another
construction, shown in FIGS. 18 and 19, a portion of the probe neck
324 may be configured to include a plurality of longitudinally
extending, circumferentially arrayed slats 324a with openings 324b
to an internal lumen 331. The slats 324a may be have a sheet-like
cross-sectional profile, or may be configured to include one or
more externally protruding structures, such as ribs 324c, in order
to increase the surface-area-to-volume ratio of the device. In yet
another construction, shown in FIGS. 20 and 21, portions of the
distal probe tip 322 and/or probe neck 324 may be configured as a
solid rod defining a plurality of longitudinally extending,
circumferentially arrayed ribs 324c alternating with plurality of
similarly disposed indentations 324d. In one modification of the
latter construction, a proximal portion of the probe neck 324 may
be configured to provide an internal lumen 331 in fluid
communication with the indentations 324d for the injection and/or
withdrawal of fluid material proximate the probe tip 322.
[0120] Finally, it is important to note that in various
constructions, and as illustrated in middle example of FIG. 14, the
end effector 320, and particularly the probe tip 322 and/or probe
neck 324, may be axisymmetric or axially asymmetric, so that the
term diameter should be understood generally as referring to the
characteristic width of the referenced part, rather than a
geometric diameter determined with respect to a single central
longitudinal axis.
[0121] In a fifth expression of the third embodiment, the medical
ultrasound handpiece assembly 300 is configured to shear-thin or
fluidize a material transiting within one more lumens in the end
effector 320. The challenge of injecting precise amounts of dermal
filler in a precise location along a facial feature 10, such as the
nasolabial fold, increases as the viscosity of the dermal filler
increases and the size of the injection needle lumen decreases.
Ultrasonic energy may be used to shear-thin the dermal filler while
the dermal filler passes from a reservoir on the surgical
instrument and through a lumen in the end effector 320. Ultrasonic
energy may also be used to shear-thin the dermal filler or to
fluidize other materials while those materials are transiting
within the end effector 320. Ultrasound handpiece assembly 300
consequently may include at least one fluid lumen 302 in fluid
communication with the end effector 320. In one construction,
ultrasonically active shaft 328 includes an internal lumen 331,
with fluid lumen 302 in fluid communication with internal lumen
331. In one exemplary construction, shown in FIG. 22, shaft 328 is
secured to ultrasound transducer 310, which may be configured as a
"Langevin stack" with an integrated fluid path. In another
construction, the interstitial space 329 between ultrasonically
inactive probe sheath 330 and shaft 328 serves as a fluid lumen,
with fluid lumen 302 in fluid communication with the proximal end
of probe sheath 330 and interstitial space 329. In one exemplary
construction, shown in FIG. 23, a fluid lumen 302 bypasses the
ultrasound transducer 310 within the handpiece assembly 300 and
joins a manifold 304 receiving the proximal end of probe sheath 330
upon assembly of the end effector 320 with the handpiece assembly
300. In one variation, the internal lumen 331 is used to suction
material from the distal end of the end effector 320, and the
interstitial space 329 is used to inject materials such as dermal
filler or irrigation fluids. In another variation, the internal
lumen 331 is used to inject materials such as dermal filler or
irrigation fluids, and the interstitial space 329 is used to
suction material from the distal end of the end effector 320. In
other variations, only one structure may serve as a fluid lumen,
and both functions may take place through that lumen. Where the
interstitial space 329 is used as a fluid lumen, the end effector
may be opened by retracting the probe sheath 330 from the dilation
region 326. Adjustment mechanisms for retracting the probe sheath
330 are described in detail in the context of the fourth embodiment
of the invention, described below.
[0122] In an implementation of the fifth expression, shown in FIG.
24, ultrasonically active shaft 328 includes an oppositely
projecting portion 336 serving as the fluid lumen 302. Portion 336
projects from a proximal end of the ultrasound transducer 310 and
within a handpiece port 306 configured for connection to a syringe
340 via, e.g., a complementary-configured port 306 and syringe tip
342 such as those in found luer lock connections. Portion 336
projects within at least the syringe tip 342, whereupon ultrasound
energy transmitted to portion 336 during operation of ultrasound
transducer shear-thins dermal filler held within syringe 340. The
handpiece port 306 is preferably located at a node 334 of the
projecting portion 336. The free end of the projecting portion 336
is preferably located at an anti-node 332 so as to maximize
shear-thinning at the entrance of the comparatively narrow-bore
fluid lumen 302. In other implementations, syringe 340 may be
combined within the handpiece assembly 300 as a unit, so that port
306 is an internal point of connection to an integrated syringe
structure.
[0123] In a method of using the expressions of the third
embodiment, a dermal filler 12 is injected into the facial feature
10, and at least the distal probe tip 322 of the device is inserted
beneath the surface of the skin 14. The dermal filler 12 may be
injected before or after insertion of the distal probe tip 322
within the skin, depending upon the source of the dermal filler,
.e.g., separate applicator or injection through a fluid lumen of
the end effector 320 (such as interstitial space 329 or internal
lumen 331). Also, the probe tip 322 may be inserted through an
existing perforation in the skin 14 (such as made by an applicator
or obturator) or through a perforation made by a distal-most blade
portion 323 of the probe tip 322. The ultrasound transducer 310 is
powered to operate the probe tip 322, and the probe tip is inserted
into the dermal filler 12 to shear-thin the filler. In one
variation of the method, the ultrasound transducer 310 is depowered
and the dermal filler 12 is manipulated from the surface of the
skin 14 while in a shear-thinned state. In another variation of the
method, the ultrasound transducer 310 is depowered and the probe
tip 322 withdrawn from the skin, whereupon the dermal filler 12 is
manipulated from the surface of the skin 14 while in a
shear-thinned state.
[0124] In a preferred implementation of the method, the probe
dilation region 326 is inserted beneath the surface of the skin 14
after the ultrasound transducer 310 is powered, whereupon the
ultrasonically inactive probe sheath 430 is inserted beneath the
skin to protect the surface of the skin 14 from unintended contact
with ultrasonically active portions of the probe. Ultrasound
transducer 320 may be depowered prior to removal of the probe
sheath 430, dilation region 326, and probe tip 422 to further
protect the surface of the skin 14. In a variation of the
implementation possible where separate instruments provide initial
penetration and dilation of the skin, the dilation region 326 is
brought into contact with the surface of the skin, whereupon the
ultrasound transducer 320 is powered and the dilation region 326
and probe sheath 430 are inserted beneath the skin.
[0125] In another method of using the expressions of the third
embodiment, the devices may be used to perform blepharoplasty. The
distal probe tip 322 is inserted beneath the surface of the skin
above a periorbital fat pad. Although the probe tip 322 may be
inserted through an existing perforation in the skin 14 (such as
made by an obturator), the skin is preferably perforated by a
distal-most blade portion 323 of the probe tip 322. The ultrasound
transducer 310 is powered to operate the probe tip 322 and to
advance the distal probe tip 322 into the periorbital fat pad.
Advantageously, devices scaled for typical dermal filler procedures
are also suitably scaled for blepharoplasty, such that the probe
dilation region 326 and the ultrasonically inactive probe sheath
330 may be inserted beneath the surface of the skin 14 during
advancement of the distal probe tip 322. This isolates the skin 14
from prolonged contact with ultrasonically active portions of the
probe. Upon reaching the interior of the periorbital fat pad, the
distal probe tip 322, and potentially a distal portion of the probe
neck 324, is manipulated within the periorbital fat pad while the
ultrasound transducer 310 is powered to fluidize and shift or lyse
and remove periorbital fat. The distal probe tip 322 may also be
used to shear-thin a dermal filler 12 that has been injected into
the periorbital fat pad in order to further shape the pad, or to
inject a dermal filler 12 to take the place of previously removed
fat.
[0126] A fourth embodiment of the invention is shown in FIGS.
25-33. The fourth embodiment is substantially similar to the third
embodiment, as heretofore described, but omits the probe dilation
region 326, and consequently the junction between the
ultrasonically inactive probe sheath 330 and the dilation region
326. In the referenced figures, elements with reference numbers
differing only in the lead digit, e.g., distal probe tips 322 and
422, should be understood to be similar or identical to those
elements described in the context of the third embodiment, but for
the above-indicated points of distinction. With specific regard to
the fourth embodiment, ultrasonically active shaft 428 is coaxially
held within the ultrasonically inactive probe sheath 430 and
operatively connected to the probe neck 424. The probe sheath 430
is configured such that the distal end of the probe sheath 430 is
slidably operable to both cover and expose at least the probe tip
422. It is important to note that in some procedures, dermal
fillers are injected substantially below the dermis, particularly
at or above the interface between the musculature and the
periosteum in order to alter facial features such as the jaw line.
Consequently, some expressions of the embodiment are adapted for
use in this application, or similar microsurgical procedures in
which ultrasonic instruments are used to inject material, remove
material, or dissect tissues at very precise locations.
[0127] In a first expression of the fourth embodiment, shown in
FIG. 25, at least a portion of the ultrasonically inactive probe
sheath 430 is longitudinally flexible and includes an S-shaped
crease 442. The crease 442 allows the distal end of the probe
sheath 430 to slidably retract in response to a longitudinal
resistance to the advancement of the probe sheath 430.
Specifically, portions of the probe sheath 430 distally adjacent to
the crease 442 may slide proximally over the crease 442, and
ultimately be folded under successive distally adjacent portions of
the sheath, in response to sufficient and continued longitudinal
resistance to advancement. This folding action causes the probe
sheath 430 to retract relative to the ultrasonically active
portions of the probe, exposing greater lengths of the probe tip
422 and probe neck 424. The stiffness of the probe sheath 430 may
be adapted such that portions of the probe sheath 430 distally
adjacent to the crease 442 will not fold into the crease as the
probe tip 422 and probe sheath 430 are advanced into soft tissue,
but will fold into the crease when the probe tip 422 is advanced
into stiff tissue such as muscle or hard tissue such bone. The
stiffness may also be adapted solely with respect to hard tissue.
Soft tissues proximate the insertion track can then be
substantially protected from ultrasonically active portions of the
probe both during and after advancement of the probe.
[0128] In a second expression of the fourth embodiment, shown in
FIG. 26, the distal end of the ultrasonically inactive probe sheath
430 includes a spring-biased mechanism 450 configured to normally
extend a distal-most segment 446 of the probe sheath 430 out from a
proximally adjoining segment 448, but slidably retract the
distal-most segment 446 in response to sufficient longitudinal
resistance to the advancement of the probe sheath 430. In one
construction, the spring-biased mechanism 450 includes at least two
circumferentially opposing elastic dogbones 452 having opposing
ends anchored to the distal-most segment 446 and the proximal
segment 448, respectively. Preferably, the elastic dogbones 452 are
configured to stretch within longitudinal slots 454 of the proximal
segment so that interference between the proximal ends of the
dogbones 452 and the proximal ends of the longitudinal slots 454
limits the travel of the distal-most segment 446 In modifications
of the construction, other structures such as internal stops in the
interior of the proximal segment 448, external stops on the
exterior of distal-most segment 446, and longitudinal grooves in
the proximal end of the distal-most segment 446 may serve as travel
limiting structures. In other constructions, coil springs or volute
springs may be used with various combinations of anchorings, slots,
and stops.
[0129] The spring force of the spring-biased mechanism 450 may be
adapted such that the distal-most segment 446 will not appreciably
expose proximal portions of the probe tip 422 as it is advanced
into soft tissue, but will operate when the probe tip 422 is
advanced into stiff tissue such as muscle or hard tissue such bone.
Soft tissues proximate the insertion track can then be
substantially protected from the ultrasonically active portions of
the probe both during and after advancement of the probe. The probe
sheath 430 and sheath segments 446, 448 are constructed from a
comparatively rigid material, and preferably constructed from
thermoplastic materials such as ULTEM.RTM. (a polyetherimide
marketed by SABIC Americas, Inc. of Houston, Tex.), fiber
reinforced composites (e.g., pultruded glass or carbon fiber
tubing), or braided catheter tubing.
[0130] In a third expression of the fourth embodiment, shown in
FIGS. 27 and 28, a proximal portion of the ultrasonically inactive
probe sheath 430 is coupled to an adjustment mechanism 460
configured to positively position the distal end of the probe
sheath 430 over at least the distal probe tip 422. In one
construction, the adjustment mechanism 460 includes an internally
threaded drive member 462 that couples to external threads 464 on
the proximal portion of the probe sheath 430. Such threads may be
integral to the proximal portion of the probe sheath 430 or be part
of an adapter bound to the proximal portion of the probe sheath
430. In another construction, the adjustment mechanism includes a
slide member 466 that is mechanically linked or chemically bound to
the proximal portion of the probe sheath 430. The adjustment
mechanism is manually or mechanically actuated to slidably operate
the distal end of the probe sheath 430 over at least the distal
probe tip 422.
[0131] The adjustment mechanism is preferably a component of the
medical ultrasound handpiece assembly 400. Positive positioning of
the distal end of the probe sheath 430 over at least the distal
probe 422 from a handpiece assembly enables ready modification of
the contact length between tissue and at least the distal probe tip
422 to a length suitable for the intended target. For example, the
distal most-end of the probe sheath 430 may be retracted to expose
a predetermined length of the probe tip 422 (and potentially the
probe neck 424, as further discussed below) corresponding to the
spread of tiers in which a dermal filler has been injected. Where a
single, small tier has been injected, only a small contact length
is needed, with greater contact lengths increasing the risk of
unintended tissue damage. Where multiple tiers have been injected,
a larger contact length may be desired so as to permit
shear-thinning of the entire tiered depth in a single procedure.
Finally, in other procedures, and particularly procedures such as
liposuction, very large contact lengths may be required into order
to employ the surgical device efficiently. For further example, as
noted above, dermal fillers may be injected even below musculature
in some procedures. Positive positioning of the distal end of the
probe sheath 430 over the distal probe tip 422 from the handpiece
assembly enables shallower tissues proximate the insertion track,
even stiff or tough tissues, to be substantially protected from
ultrasonically active portions of the probe after further
advancement of ultrasonically active portions of the probe.
[0132] In implementations of the expressions of the fourth
embodiment, shown in FIG. 29, the distal probe tip 422 may be a
blunt tip with an opening to an internal lumen 431 continuing
through the probe neck 424 and ultrasonically active shaft 428 to
establish fluid communication with the handpiece assembly 400. The
blunt tip is atraumatic and will tend to stay within structures
like fat pockets once it has been introduced. The blunt tip may
also be used in other procedures to sculpt bone and cartilage or to
remove deposits. Alternately, the probe tip 422 may be a beveled
needle tip with a distal-most blade portion 423 and an opening to
the internal lumen 431. The needle tip is useful for penetrating
tough tissues such as fascia. Probe tip and probe neck
configurations such as those described in the context of the third
embodiment are envisioned as well. Finally, the distal-most portion
of the ultrasonically inactive probe sheath 430 may be blunt, but
may alternately be beveled to aid in insertion into soft
tissue.
[0133] In further implementations of the expressions of the fourth
embodiment, shown in FIGS. 30 and 31, the probe neck 424 may
include a plurality of slots 470 opening into an internal lumen
431. As indicated earlier, probe tip configurations such as those
described in the context of the third embodiment are envisioned as
well, so that internal lumen 431 may or may not extend distally
into distal probe tip 422. In a first construction, the plurality
of slots is configured as a longitudinal array of slots 472. This
allows the device to provide additional injection or suction
capability along an extended length of the active probe when the
probe neck 424 is exposed. In a second construction, the plurality
of slots is configured as a plurality of longitudinally elongated,
circumferentially arrayed slots 474 alternating with plurality of
similarly elongated and disposed bridges 476. The bridges, of
course, join proximal and distal portions of the probe neck 424.
However, the bridges will also develop a transverse mode of
vibration when the probe neck 424 (and ultrasonically active shaft
428 and probe tip 422) are driven longitudinally by the ultrasound
transducer 410. The plurality of slots 474 and alternating bridges
476 are preferably located at a node 434. When the bridges 476
experience transverse vibration, proximate dermal filler will be
readily shear-thinned. Where tissue removal can be performed, or in
other procedures such a liposuction, soft tissues proximate to the
bridges 476 will be readily lysed for suction by the end effector
420. The applicants note that in other procedures, the probe sheath
430 may be partially or completely omitted in favor of a separate
obturator, with the remainder of the probe scaled to dimensions
generally unsuitable for dermal applications. A probe sheath 430,
if any, would serve to protect the user from accidental contact
with the active portions of the probe 428 at the proximal end of
the end effector 420, with a distal end of the end effector being
exposed for several inches or more. The longitudinal array of slots
472 may then be configured as a longitudinal array where each
longitudinal position in the array includes a plurality of
longitudinally elongated, circumferentially arrayed slots 474
alternating with plurality of similarly elongated and disposed
bridges 476. The longitudinal positions in the array may correspond
to nodes 434. Such a extended-length device may be usefully
employed in conventional liposuction procedures occuring
essentially within the hypodermis.
[0134] In yet further implementations of the expressions of the
fourth embodiment, where all of the ultrasonically active shaft
428, probe neck 424, and distal probe tip 422 include an internal
lumen 431, and the shaft 428 and ultrasonically inactive probe
sheath 430 form an interstitial space 429, a proximal portion of
the probe neck 424 may include a lateral aperture 480 for fluid
communication between the internal lumen 431 and the interstitial
space 429, and a seal 482 disposed proximally from the lateral
aperture 480 to seal the internal lumen 431. At least one cannula
484 providing an inner lumen 486 may penetrate the seal 482 and
extend distally from the lateral aperture 480. In one variation,
the cannula 484 extends distally to the distal probe tip 422. In
another variation, the proximal portion of the probe neck 484 is
configured as a distally-opening bell 486, with the lateral
aperture 480 being disposed in the narrowing portion of the bell.
In this variation, the probe sheath preferably seals
(generally--the seal does not need to be complete or particularly
efficient) against the probe neck 424. The cannula 484 may be used
for suction or to inject materials such as dermal filler or
irrigation fluids. The distal portion of the internal lumen 431,
i.e., that portion distal from the seal 482, may be also be for
suction or to inject materials such as dermal filler or irrigation
fluids. In a preferred mode of operation, the cannula 484 is used
for suction and the internal lumen is used for irrigation. The
slots 472 or 474 described previously may present. In the preferred
mode of operation, the slots 472 or 474 may serve as irrigation
paths to establish a longitudinally-oriented `flushing circuit` for
tissue and tissue debris generated by ultrasonic operation of the
probe tip 422 and probe neck 424.
[0135] In a method of using the expressions of the fourth
embodiment, the distal probe tip 422 of the device is inserted
beneath the surface of the skin 14. The probe tip 422 may be
inserted through an existing perforation in the skin 14 (such as
made by an applicator or obturator) or through a perforation made
by a distal-most blade portion 423 of the probe tip 422. The
ultrasound transducer 410 is powered to operate the probe tip 422.
The distal end of the ultrasonically inactive probe sheath 430 is
inserted beneath the surface of the skin 14. As the probe tip is
advanced, the distal end of the probe sheath 430 is retracted to
expose a greater length of at least probe tip 422. In one
variation, the retraction of the distal end of the probe sheath 430
is caused by a longitudinal resistance to the advancement of the
distal end of the probe sheath 430. In another variation, the user
retracts the distal end of the probe sheath using an adjustment
mechanism 460. In another variation, the distal end of the probe
sheath 430 initially covers substantially all proximal portions of
the probe tip 422, with retraction of the distal end of the probe
sheath exposing proximal portions of the probe tip only after an
initial penetration of the skin.
[0136] In an implementation of the method, a dermal filler 12 is
injected into the facial feature 10. The dermal filler 12 may be
injected before or after insertion of the probe tip 422 within the
skin, depending upon the source of the dermal filler, .e.g.,
separate applicator or injection through a fluid lumen of the end
effector 420 (such as interstitial space 429 or internal lumen
431). The probe tip is used to shear-thin the dermal filler 12. In
one variation of the implementation, the ultrasound transducer 410
is depowered and the dermal filler 12 is manipulated from the
surface of the skin 14 while in a shear-thinned state. In another
variation of the method, the ultrasound transducer 410 is
depowered, and the probe tip 422 and probe sheath 430 withdrawn
from the skin, whereupon the dermal filler 12 is manipulated from
the surface of the skin 14 while in a shear-thinned state.
[0137] In another implementation of the method, the device is used
to perform blepharoplasty. The distal probe tip 422 is inserted
beneath the surface of the skin above a periorbital fat pad. Upon
reaching the interior of the periorbital fat pad, the distal probe
tip 422, and potentially a distal portion of the probe neck 424,
may be manipulated within the periorbital fat pad while the
ultrasound transducer 410 is powered to fluidize and shift or lyse
and remove periorbital fat. The distal probe tip 422 may also be
used to shear-thin a dermal filler 12 that has been injected into
the periorbital fat pad in order to further shape the pad, or to
inject a dermal filler 12 to take the place of previously removed
fat. In a variation of the method, presented in the context of the
present implementation, the distal end of the ultrasonically
inactive probe sheath 430 is separable from the ultrasonic surgical
instrument, e.g., by separating a frangible portion of the probe
sheath 430 providing a perforated or scored periphery, or
uncoupling coupling between distal and proximal portions of the
probe sheath. The distal end of the probe sheath 430 is separated
from the instrument (although still coaxially positioned on the
instrument), whereupon the instrument is withdrawn while the
separated distal end of the probe sheath remains in place beneath
the surface of the skin. The separated distal end of the probe
sheath 430 can thus function as an obturator, and the ultrasonic
surgical instrument can later be reinserted through this obturator.
Also, other surgical instruments, exploratory instruments,
cannulae, and the like can be inserted through this obturator as
part of a greater surgical procedure. The separated distal end of
the probe sheath is, of course, eventually withdrawn from beneath
the skin to complete that stage of the overall surgical
procedure.
[0138] The expressions of the third and fourth embodiments
advantageously shear-thin dermal fillers to make injection
procedures more precise while simultaneously enabling the use of
highly molecular weight, high longevity biomaterials. The same
ultrasound end effector may be used to inject dermal fillers and to
facilitate the bloodless dissection of tissue, as well as to create
pockets for dermal filler and/or to remove unwanted tissue, such as
fat. The end effectors 320 and 420 also may be used in vivo to thin
previously injected filler so that it can be finger massaged to the
desired location and thickness, as well as to remove excess filler
if it has been inadvertently injected. If irrigation of a tissue
pocket is desired, the same fluid lumen may be used for suction
irrigation as for dermal filler injection and adjustment.
[0139] In a fifth embodiment of the invention, shown in FIGS.
33-76, the active portions of medical ultrasound handpiece
assemblies 300 or 400 (and similar devices) and contact end
effectors 320 or 420 (and similar devices) may be constructed from
a single crystal or polycrystalline resonating material,
principally silicon, although germanium, diamond, and sapphire may
also be used. Preferably, these structures are manufactured from a
semiconductor wafer so as to be manufacturable using existing
semiconductor processes. In addition, the transducer material may
be a lead-free piezoelectric material, such as barium titanate, or
a magnetostrictive material, such as nickel or "GALFENOL"
(gallium-iron alloys marketed by ETREMA Products, Inc. of Ames,
Iowa), so that the device may be both inexpensive enough to be
employed as a single use device and suitable for disposal as
ordinary medical waste, as opposed to lead-bearing hazardous waste.
Other transducing materials, including ceramic PZT materials and
electrostrictive materials, as well as single crystal materials,
can also be used. PZT materials are typically lead-bearing, but
have generally better piezoelectric performance. Electrostrictive
materials are also frequently lead-bearing, but exhibit less
hysteresis than piezoelectrics, have higher strain energy densities
than piezoelectrics, and do not need to be poled; however
electrostrictive materials also have greater temperature
sensitivity, require greater differential voltages, and require
different modes of electrical control (since strain varies
quadratically rather than linearly with respect to the applied
voltage). Electrostrictive transducer structures and transducers
may be manufactured from materials such as PMN (lead magnesium
niobate), PSN (lead strontium niobate), or PMN-PT (lead magnesium
niobate with lead titanate dopant), and may be driven in either a
d.sub.31 or d.sub.33 mode. Magnetrostrictive materials do not
require poling, are ductile, can be used with low voltage drive
circuits, and permit the use of designs which minimize potential
electrical leakage by electrically isolating the waveguide and end
effector from the surrounding electromagnetic coil, electrical
contacts, and handpiece housing; however magnetostrictive materials
are subject to eddy current effects and magnetostrictive power
transfer is comparatively less power efficient, so as to require
some form of active cooling of magnetostrictive actuators and
surrounding electromagnetic coils.
[0140] The fifth embodiment, illustrated schematically in FIGS. 33
and 34, includes an ultrasonic core 510 for an ultrasonic surgical
apparatus including a longitudinally elongated, generally planar
waveguide 590 constructed from a single crystal or polycrystalline
material, and a transducer structure 600 including one or more
transducers 602 affixed to the waveguide 590. The waveguide
material is preferably silicon. For sake of clarity in the
following discussion, the term "end" will be understood as
referring to a longitudinal boundary, or a surface representing
such a boundary; the term "edge" will be understood as referring to
a lateral boundary, or surface representing such boundary, in a
direction within the plane of the waveguide 590; and the term
"side" will be understood as referring to a lateral boundary, or
surface representing such a boundary, in a direction perpendicular
to the plane of the waveguide 590.
[0141] The waveguide 590 includes, in order, a first resonator or
proximal end portion 592, a transduction portion 594, and a second
resonator or distal end portion 596, as well as optional ancillary
structures such as mounts or mount connections, intermediate gain
stage structures, and the like which may be formed between
components 592, 594, and 596. In one construction, the waveguide
590 is a monolithic structure. In another construction, shown in
FIG. 34, the waveguide 590 is a laminated structure including a
plurality of planar layers 590a, 590b, etc. of the material. In one
variation of the latter construction, two adjoining layers, e.g.,
590a and 590b, may define a longitudinal channel, or other internal
voids, which may serve, for example, as an internal lumen 591. In
another variation of the latter construction, adjacent layers 590c
and 590e may be separated by other materials, as further described
below, in the laminated structure. The fifth embodiment may also
include a single or polycrystalline material end effector portion
520a, such as those shown in FIG. 35, configured to serve at least
as an ultrasonically active shaft 528. The end effector portion
520a preferably is configured to serve as a complete surgical probe
(excepting ultrasonically inactive components such as the probe
sheath 530); for example, one having an ultrasonically active shaft
528 and a distal probe tip 522. In one construction, the end
effector portion 520a and the waveguide 590 (or a plurality of the
layers thereof) are a monolithic structure, and thus monolithically
coupled. Such a construction is suitable for precision
microsurgical procedures such as dermatological procedures, dermal
filler procedures like those described above, or neurological or
hand surgeries. In another construction, the end effector portion
520a and the waveguide 590 are resonantly adjoining, i.e.,
resonantly connected at a node 534 for the transmission of a mode
of vibration, and thus resonantly coupled.
[0142] In a first expression of the fifth embodiment, shown in
FIGS. 36-41, the second resonator 596 of waveguide 590 is
configured to vary the magnitudes and/or modes of ultrasonic
vibration created in the transduction portion 594 prior to
transmission into an end effector portion 520a. The second
resonator 596 includes a proximal end 596a having first transverse
extent, e.g., a width w.sub.p, a distal end 596b having a second,
lesser transverse extent, e.g., a width w.sub.d, and a body
generally narrowing between the first and second transverse extents
so as to create vibrational gain. In various constructions, the
edges 596c and 596d of the second resonator 596 may be sinusoidally
curved (FIG. 37 bottom), convexly or concavely curved (FIG. 36, top
and bottom), constantly tapered (FIG. 37 top left), discontinuously
stepped (FIG. 37 top right), or a shaped with a combination of any
of the foregoing to vary the mode of ultrasonic vibration and,
typically, to separate desirable modes of vibration from
undesirable modes of vibration. As shown in FIG. 37, bottom
instance, portions of a transducer 602 may extend over the proximal
end 596a of the second resonator 596, which in a monolithic
structure such as the present waveguide 590 is generally
distinguished by a rapid change in geometry near a node 534, or (as
in FIG. 37 bottom) an intermediate or stack node 535.
[0143] In a first construction of the first expression, shown in
FIG. 38, the second resonator 596 is symmetric with respect to the
central longitudinal axis of the waveguide 590 and has a
substantial body portion with an essentially invariant transverse
extent matching the second transverse extent of the distal end
596b. This symmetric and highly uniform construction can create a
transverse mode of vibration at a subharmonic frequency,
.omega..sub.n/N (where N=1, 2, 3, etc.), when transduction portion
594 is longitudinally vibrated at a primary frequency,
.omega..sub.n, due to autoparametric resonance. An end effector
portion 520a coupled to the second resonator 596 may be configured
to operate in a transverse working mode at a frequency equal to the
subharmonic frequency, so that the mode of ultrasonic vibration is
effectively transformed from a longitudinal driving mode at
frequency .omega..sub.n to a transverse working mode at frequency
.omega..sub.n/N.
[0144] In a second construction of the first expression, the second
resonator 596 is asymmetric with respect to the central
longitudinal axis of the waveguide 590. In an exemplary
construction, shown in FIG. 39, the edges of the second resonator
are asymmetric with respect to the central longitudinal axis of the
wave guide 590, with one edge 596c of the second resonator 596
being sinusoidally curved and the opposite edge 596d of the second
resonator 596 being concavely curved. In other exemplary
constructions, edges 596c and 596d may be shaped with one or more
of the foregoing shapes, but are not identically shaped. These
asymmetric constructions cause symmetric shear mode vibrations
which create an additional transverse mode of vibration in proximal
end 596a when transduction portion 594 is longitudinally vibrated.
In another exemplary construction, shown FIG. 40, the body of the
second resonator is rendered asymmetric with respect to the central
longitudinal axis of the wave guide 590 by at least one aperture
597. The aperture 597 may be a slot extending partially
longitudinally and partially laterally inwards from an edge 596c or
596d of the second resonator 596. In one modification (FIG. 40
middle) apertures 597 may be a staggered array of holes. In another
modification (FIG. 40 bottom) the aperture 597 may be a
longitudinally extending, sinusoidal slot. These asymmetric
constructions cause the longitudinal resonant mode to couple into
an additional torsional mode of vibration when transduction portion
594 is longitudinally vibrated.
[0145] In a third construction of the first expression, shown in
FIG. 41, the second resonator 596 may include a gain portion 603 of
a transducer 602 generally affixed to the adjoining transduction
portion 594 of waveguide 590. The gain portion 603 may include a
proximal end 603a having first transverse extent, e.g., a width
w.sub.p, a distal end 603b having a second, lesser transverse
extent, e.g., a width w.sub.d, and a body generally narrowing
between the first and second transverse extents so as to create
vibrational gain. In various constructions, the edges 603c and 603d
of the gain portion 603 may be sinusoidally curved, convexly or
concavely curved, constantly tapered, discontinuously stepped, or a
shaped with a combination of any of the foregoing to vary the mode
of ultrasonic vibration at the a distal end 596b of second
resonator 596. The gain portion 603 may structured, affixed to the
second resonator 596, and powered in essentially the same manners
discussed below in the context of the transducer 602 and the
transduction portion 594. The exposed side of the gain portion 603
may also be tapered from the proximal end 603a to the distal end
603b, i.e., the gain portion 603 may gradually reduce in thickness,
as an additional means of increasing gain.
[0146] In a second expression of the fifth embodiment, shown in
FIGS. 42-59B, at least one transducer 602 is affixed to a side of
the transduction portion 594 of waveguide 590. In a first
construction of the second expression, shown in FIG. 42, the
transducer 602 is a piezoelectric or electrostrictive ceramic
directly bonded to a side of the transduction portion 594. In a
first variation of the first construction, the bonded surface of
the transduction portion 594 may consist essentially of an oxygen
rich surface layer, e.g., silicon dioxide (SiO.sub.2), to insulate
the transducer 602 from the transduction portion 594. In a second
variation of the first construction, the bonded surface of the
transduction portion 594 may consist essentially of elemental
silicon (Si), elemental silicon containing a dopant (Si.sub.d), or
a silicide. The substrate of the transduction portion 594 in the
second variation may consist essentially of elemental silicon or
elemental silicon containing a dopant (i.e., bulk-doped silicon).
Where the subsurface of the transduction portion 594 consists
essentially of undoped elemental silicon, an embedded path 610 of
silicon containing a dopant, or silicide, may be included to
provide a preferential electrical path. Other surfaces of the
waveguide 590 may be insulated by an oxygen rich surface layer
formed on the waveguide 590 to prevent unintentional grounding. At
least one electrical contact 612 may be provided on the waveguide,
e.g., on an exposed surface of the transduction portion 594,
proximate a node 534. An exemplary electrical contact 612, shown in
cross section in FIG. 43, is a solder pad penetrating the oxygen
rich surface layer (if present), in electrical contact with the
subsurface of the transduction portion, and in electrical contact
with the embedded path 610 (if present). In one exemplary
construction, the electrical contact 612 includes an
aluminum-copper alloy bonding layer 614, a nickel pad 616, and a
gold top coat 618. A ground wire may be soldered to the electrical
contact 612 to complete the ground path for the transducer 602.
[0147] In a third variation of the first construction, shown in
FIGS. 44 and 45, the transducer 602 is a piezoelectric or
electrostrictive ceramic directly bonded on opposite sides to the
transduction portions 594 of adjacent or adjoining layers 590a and
590b of a laminated waveguide 590. In a further variation, one
layer may serve as an electrical source for the
interstitially-disposed transducer 602 (when wired to an electrical
source), and the other adjacent or adjoining layer may serve as an
electrical ground (when wired to ground). In such a variation, the
structure of the transduction portions 594 of both layers 590a and
590b may be the same as that described above, with an oxygen rich
surface layer insulating adjoining portions, if any, of the
transduction portions 594 of the layers. Alternately, the laminant
between adjoining layers 590a and 590b may be an insulator. An
exemplary laminant (not intended to be interpreted as "other
materials" or to cause layers 590a and 590b to be considered
adjacent rather than adjoining) is a silicon-to-silicon anodic
bonding glass layer.
[0148] In a fourth variation of the first construction, shown in
FIGS. 46 and 47, the transducer 602 is a piezoelectric or
electrostrictive ceramic directly bonded to both sides of the
transduction portion 594. The transduction portion 594 includes at
least one aperture 595 which is filled by a bridging portion 604 of
a monolithic transducer 602. Abutment portions 606a and 606b of the
transducer 602 abut the respective sides of the transduction
portion 594 adjacent the at least one aperture 595. In addition to
direct bonding of the transducer 602 with the transduction portion
594, mechanical abutment between the portions 604, 606a, 606b of
the transducer 602 and the transduction portion 594 further affixes
the transducer to the sides of the transduction portion 594. The
transducer 602 may be formed in place by slip-forming and sintering
the transducer material on the transduction portion 594.
[0149] In a second construction of the second expression, the
transducer 602 is clamped to a side of the transduction portion
594. This clamped constuction is a simple mechanism for attachment,
but also may be used to preload ceramic and single crystal
transducers to increase power and displacement during shear mode
operation of the transducer 602. In a first variation of the second
construction, shown in FIGS. 48 and 49, the transduction portion
594 includes at least one aperture 595 and the transducer 602
includes at least one corresponding aperture 605. The aperture(s)
595 are preferably positioned at an anti-node 532. The
corresponding apertures 595 and 605 are axially aligned and receive
a compressive fastener 620, such as a bolt or rivet. In one
modification, a plate 622 is disposed between an otherwise exposed
side of the transducer 602 and the fastener 620 to distribute
clamping forces over the transducer 602. In another modification
(not specifically shown), a plate 624 is disposed between an
otherwise exposed side of the transduction portion 594 and the
fastener 620 to relieve local stress on the transduction portion
594 adjacent the aperture 595. As illustrated in FIG. 50, multiple
transducers 602 and, if appropriate, multiple plates 622 may be
clamped to the transduction portion 594 by the same compressive
fastener 620. In a second variation of the second construction,
shown in FIGS. 51A and 51B, a metal band 626 may be secured around
the transduction portion 594 and transducer 602. The metal band is
preferably heated, positioned, and allowed to cool to generate the
clamping force. In one modification, a plate 622 is disposed
between an otherwise exposed side of the transducer 602 and the
metal band 626 to distribute clamping forces over the transducer
602. In another modification (not specifically shown), a plate 624
is disposed between an otherwise exposed side or edge of the
transduction portion 594 and the metal band 626 to relieve local
stress on the transduction portion 594 under the metal band 626. As
illustrated in FIGS. 51A and 51B, multiple transducers 602 and, if
appropriate, multiple plates 622 may be clamped to the transduction
portion 594 by the same metal band 626.
[0150] In a third construction of the second expression, the
transducer 602 is indirectly bonded to the transduction portion 594
by an adhesive or braze 601. Exemplary adhesives are epoxies,
urethane acrylates, and cyanoacrylates, while exemplary brazes are
set out in Table 1. In a first variation of the third construction,
a proximal end 602a and a distal end 602b of the ultrasound
transducer 602 are longitudinally compressed during bonding with
the adhesive or braze 601. Once the adhesive has cured or the braze
has cooled, the ultrasound transducer 602 remains residually
compressed by the established bond between the transducer 602, the
adhesive or braze 601, and the transduction portion 594. In a
further variation, shown in FIG. 52A, a distal end plate 628 may be
similarly bonded to the waveguide 590, in an abutting relationship
with the distal end 602b, to resist decompression of the transducer
602 and, during construction, to distribute compressive forces over
distal end 602b of the transducer 602. The distal end plate 628 may
conveniently be similarly bonded to the distal end 602b to form an
integrally bonded assembly. In a yet further variation, also shown
in FIG. 52A, an end mass 640 may be similarly bonded to the first
resonator or proximal end portion 592 of the waveguide 590, in an
abutting relationship with the proximal end 602a, to resist
decompression of the transducer 602 and, during construction, to
distribute compressive forces over the proximal end 602a of the
transducer 602. Where necessary or desirable, an adhesion layer may
be applied to the bonding surfaces. The adhesion layer for an
electrically conductive surface to be brazed with one of the
compositions described herein may be prepared, for example, with a
nickel plate and a gold top coat.
TABLE-US-00001 TABLE 1 Brazing Compositions and Temperatures
Melting range Melting range Mushy solidus liquidus range (.DELTA.)
Alloy composition .degree. C. .degree. F. .degree. C. .degree. F.
.degree. C. .degree. F. 70Sn/30Pb 183 361 193 380 10 19 63Sn/37Pb
183 361 183 361 0 0 60Sn/40Pb 183 361 190 375 7 14 50Sn/50Pb 183
361 216 420 33 59 40Sn/60Pb 183 361 238 460 55 99 30Sn/70Pb 185 365
255 491 70 126 25Sn/75Pb 183 361 266 511 83 150 10Sn/90Pb 268 514
302 575 34 61 5Snl95Pb 308 586 312 594 4 8 62Sn/36Pb/2Ag 179 355
179 355 0 0 10Sn/88Pb/2Ag 268 514 290 554 22 40 5Sn/95Pb 308 586
312 594 4 8 625Sn/36Pb/2.5Ag 179 355 179 355 0 0 10Sn/88Pb/2Ag 268
514 290 554 22 40 5Sn/90Pb/5Ag 292 558 292 558 0 0 5Sn/92.5Pb/2.5Ag
287 549 296 564 9 15 5Sn/93.5Pb/1.5Ag 296 564 301 574 5 10
2Sn/95.5Pb/2.5Ag 299 570 304 579 5 9 lSn/97.5Pb/1.5Ag 309 588 309
588 0 0 96.5Sn/3.5Ag 221 430 221 430 0 0 95Sn/5Sb 235 455 240 464 5
9 42Sn/58Bi 138 281 138 281 0 0 43Sn/43Pb/14Bi 144 291 163 325 19
34 52Sn/48In 118 244 131 268 13 24 70In/30Pb 160 320 174 345 14 25
60In/40Pb 174 345 185 365 11 20 70Sn/18Pb/12In 162 324 162 324 0 0
90Pb/5In/5Ag 290 554 310 590 20 36 92.5Pb/51In/2.5Ag 300 572 310
590 10 18 97.5Pb/2.5Ag 303 578 303 578 0 0 Source: Charles A.
Harper, Electronic Packaging and Interconnection Handbook (4th
Ed.), McGraw-Hill, 2004.
[0151] In manufacturing devices in accordance with the third
construction, one can affix a pre-poled transducer 602 upon the
transduction portion 594 of the waveguide 590; however, assembly
processes employing high temperature/fast cure adhesives or typical
brazes may depole the piezoelectric material during the assembly
process. Consequently, a preferred method of manufacturing an
ultrasonic core, diagrammed in FIG. 52B, involves selecting a
single crystal piezoelectric material cut along a predetermined
crystallographic plane and disposing said single crystal
piezoelectric material between an opposing pair of planar
electrodes such that poling the material via the planar electrodes
favors the generation of piezoelectric mechanical stress in a
direction parallel to the planes of the electrodes. As a result, as
shown in FIGS. 52C and D, the transducer 602 may be bonded to the
waveguide 590 to assemble the ultrasonic core, and the transducer
may be poled after assembly of the ultrasonic core, permitting the
use of fast cure adhesives or high temperature brazes. In a first
step of the method 1010, one selects a single crystal piezoelectric
material and cuts the material to form a plate having major faces
coincident with the <011> crystallographic plane. In a second
step 1020, one adds at least one planar electrode member 608 to a
major face of the plate. It will also be apparent that an opposing
planar electrode member 608 may be added to the opposite major face
of the plate, and that either or both electrode members may be
subdivided or otherwise configured as a plurality of electrode
members, etc. In a third step 1030, one bonds the opposite major
face of the plate to a side of a longitudinally elongated,
generally planar waveguide 590. As in the fifth embodiment
generally, it is preferred that the waveguide 590 is constructed
from a single crystal or polycrystalline material, and highly
preferred that the material be principally silicon. It should be
noted that the transduction portion 594 of the waveguide 590 may
itself serve as a planar electrode (in the manner illustrated in
FIG. 42), or be provided with an adhesion layer or electrical
contacts 612 (for example, contacts such as those illustrated in
FIG. 43) to be brazed to the opposing planar electrode member 608.
The bonding material used may be a conductive adhesive, e.g.,
conductor-filled epoxies or acrylates such as the epoxies disclosed
in U.S. Pat. No. 4,210,704, or a braze, such as those described in
Table 1. In a fourth step, 1040, one applies a poling current
across the planar electrode member 608 and plate, to the waveguide
590 or opposing planar electrode member 608, to pole the single
crystal piezoelectric material in the <011> direction (i.e.,
as used in the art, a direction perpendicular to the <011>
crystallographic plane).
[0152] The transducer 602 formed by this method may, depending upon
cut direction "c," be operated in a transverse extension mode
(d.sub.31, illustrated as "TE"; cut direction zxt +0.degree.) as
shown in FIG. 52C, or a longitudinal shear mode (d.sub.36,
illustrated as "LS"; cut direction zxt +45.degree.) as shown in
FIG. 52D. For a transverse extension mode transducer, it is
preferred that the ratios of longitudinal extent to lateral extent
between edges of the transducer and longitudinal extend to
thickness each be greater than 5 to 1. For a longitudinal shear
mode transducer, it is preferred that the ratios of longitudinal
extent to lateral extent between edges of the transducer and
longitudinal extent to thickness each be greater than 3.5 to 1.
Exemplary single crystal piezoelectric materials suited for use
with the method include PMN-PT (lead magnesium niobate with lead
titanate dopant) and PIN-PMN-PT (lead indium niobate-lead magnesium
niobate with lead titanate dopant), available from sources such as
H.C. Materials Corp. of Bolingbrook, Ill., USA.
[0153] In one alternative to the third construction, shown in FIG.
53A, the transducer 602 is indirectly bonded to a carrier 630 by an
adhesive or braze 601, and the carrier 630 is subsequently bonded
to the transduction portion 594 as a subassembly. The carrier 630
is preferably constructed from silicon, but other similarly
temperature resistant substrates may be used. The
carrier-transducer subassembly may advantageously be prepared
separately from preparation of the waveguide 590 and non-transducer
structures such as the first resonator 592 and the second resonator
596, as well as any end effector portion 520a. The carrier 630 may
also be bonded to the transduction portion 594 with a low
temperature process, permitting the emplacement and use of surface
mount-like electrical contacts, e.g., electrical contact 612, on
the carrier 630 and/or waveguide 590 during the attachment of the
carrier-transducer subassembly to the transduction portion 594, and
preventing the potential depoling of the transducers 602. The
carrier 630 could then be underfilled with a non-conductive
adhesive around the joined surface mount electrical contacts.
Alternately, the carrier 630 may be bulk-doped silicon, permitting
conductive direct bonding to a bulk-doped silicon transduction
portion 594 via a low-temperature silicon fusion process.
[0154] This may be particularly advantageous if the transducer 602
would otherwise be bonded to silicon with a high temperature braze
(solidus melting point of >275.degree. C.). In a further
variation, the carrier 630 is indirectly bonded to the transduction
portion 594 by a low temperature braze 601, such as the Sn--Bi and
Sn--In alloys listed in Table 1. In yet another variation, the
carrier 630 is indirectly bonded to the transduction portion 594 by
a conductor-filled epoxy, such as those disclosed in in U.S. Pat.
No. 4,210,704, or a conductor-filled acrylate, such as those
disclosed in European Patent No. 0144741. In another further
variation, a silicon carrier 630 is laminated to the transduction
portion 594 by silicon-glass-silicon anodic bonding. Silicon
dioxide layers can be grown on the silicon carrier 630 and
transduction portion 594, and a glass layer can be sputtered or
deposited by a sol-gel process upon one of the silicon dioxide
layers, followed by assembly and bonding using a DC voltage applied
across the assembly, resulting in covalent bonding between the
silicon dioxide and glass layers. Due to the insulating nature of
the anodic bonding surface preparation and bond, the carrier may be
provided with electrical contacts 612 and conductive paths 610 in
the manner illustrated and discussed above with respect to FIGS. 42
and 43 and below with respect to FIGS. 58A-59B.
[0155] In a variation of the alternative, shown in FIGS. 53B-53D,
the transducer 602 is dimensioned to have a greater longitudinal
extent than that of the carrier 630, i.e., the ends of the
transducer 602 project beyond the ends of the carrier 630. The
larger transducer 602 (or smaller carrier 630) advantageously
allows the subassembly to be polled after the transducer 602 is
affixed to the carrier 630 by applying electrodes to poling
surfaces 602z disposed on the proximal end 602a and distal end 602b
of the ultrasound transducer 602. The relative sizing of the
transducer 602 and carrier 630 are not critical to poling via the
transducer end surfaces, but advantageously reduce the precision
and accuracy required for polling electrode positioning versus
arrangements such as that shown in FIG. 53A, in which poling
electrodes must essentially abut the carrier 630 in order to fully
contact the transducer ends. Consequently, a preferred method of
manufacturing an ultrasonic core, diagrammed in FIG. 53E, involves
the step 1110 of obtaining both a transducer having a first
longitudinal extent and a carrier having a second, shorter
longitudinal extent. In a second step of the method 1120, one bonds
the transducer 602 to a side of the carrier 630 to form a
subassembly in which the ends of the transducer 602 project beyond
the ends of the carrier 630. In a third step of the method 1130,
one applies a pair of poling electrodes to the ends of the
transducer 602 and applies a poling current through the transducer
602 via the pair of poling electrodes. In a fourth step of the
method 1140, one subsequently bonds the opposite side of the
carrier 630 to a side of a longitudinally elongated, generally
planar waveguide 590 constructed from a single crystal or
polycrystalline material. It is important to note that the
transducer 602 is preferably not bonded to the carrier 630 across
the entirety of their mutually opposing sides, but rather by a
discontinuous pattern of balls or edge-to-edge oriented strips of
bonding material 601. This first bonding material 601 is preferably
a non-conductive, high strength adhesive such as unfilled expoxies,
urethane acrylates, or the like, but could be a conductive high
strength adhesive or low flow braze.
[0156] In a subsequent step 1150, the transducer 602 may be
provided with opposing driving electrodes 608, as illustrated in
FIGS. 53B and 53C. The otherwise exposed side of the transducer 602
may be provided with a first driving electrode 608 by screen
printing, shadow mask vapor deposition, or the like. The side of
the transducer 602 bonded to the carrier 630 may be provided with a
second driving electrode 608 by underfilling the transducer with a
second bonding material which is conductive, such as a metal-filled
or carbon-filled epoxy or acrylate, or with a low temperature, free
flowing braze. Such an underfill serves to surround the other
bonding material 601 between the transducer 602 and carrier 630 and
to provide a discontinuous drive electrode 608 or, where the other
bonding material 601 is a conductive material, a composite drive
electrode 608 for conducting current across the sides of the
transducer 602. In one variation of the method step, the underfill
may be introduced to the space between opposing sides of the
transducer 602 and carrier 630 from the edges and/or ends of the
transducer. In another variation of the method step, the underfill
may be introduced to the space between opposing sides of the
transducer 602 and carrier 630 through a plurality of through-holes
631, similar to through-silicon vias (or TSVs), disposed in the
carrier 630 underneath the transducer. In this later variation, the
underfill may advantageously be introduced and formed as part of
the assembly process of the carrier 630 upon the transduction
portion 594 of the waveguide 590, and remain at least partially
disposed within the through-holes 631 so as to serve as an
electrical connection to the transduction portion. In an exemplary
construction, illustrated generally in FIG. 53D, a
carrier-transducer subsassembly formed by this method is
longitudinally polled and operated in a transverse shear mode
(d.sub.15, illustrated as "TS"; cut direction xzt
-22.5.degree.).
[0157] In another alternative to the third construction, shown in
FIGS. 53F and 53G, a magnetrostrictive transducer 602 and
surrounding encased coil 603 may be substituted for the
piezoelectric materials otherwise described. The magnetostrictive
transducer 602 advantageously does not require poling, and thus may
be quickly and securely bonded to the waveguide 590 using a fast
cure adhesive or high temperature braze 601. The magnetostrictive
transducer 602 may include an aperture 605 configured to receive a
proximal end portion of the transduction portion 594 of the
waveguide 590, in which case the first resonator 592 included in
other constructions of the fifth embodiment may be omitted. The
magnetostrictive transducer 602 is preferably a laminated structure
formed from multiple layers 602m, 602n, 602o, etc. of
magnetostrictive material so as to reduce eddy current losses
during excitation within an oscillating magnetic field. Thus, in a
first construction of the alternative, the aperture 605 may be
formed parallel to the layers of magnetostrictive material by
omitting a distal portion of one or more layers of magnetostrictive
material, e.g., 602p, and in a second construction of the
alternative, the aperture may be formed perpendicular to the layers
of magnetostrictive material by any of various known techniques
(molding, cutting, etc.). The transduction portion 594 is disposed
within the aperture and secured by an adhesive or a braze 601, such
as one from Table 1, in order to minimize acoustical impedance
between the transducer 602 and the waveguide 690. Because operation
of the magnetostrictive ultrasonic core, including transducer 602
and waveguide 590, requires the application of electrical current
to only the encased coil 603, this alternative is particularly well
suited for use in instruments employing the fluid communications
configuration shown in FIG. 23--the encased coil 603 may be more
easily insulated to prevent electrical leakage into irrigation
fluids, cooling fluids, or the like communicated between the
encased coil 603 and the ultrasonic core 510 than the more complex
transducer structures 600 and transduction portions 594 of the
waveguide 590 in other constructions.
[0158] In a fourth construction of the second expression, shown in
FIGS. 54-56, at least one transducer 602 is affixed to the
transduction portion 594 of waveguide 590 and configured to create
a transverse mode of vibration. In a first variation of the fourth
construction, shown in FIG. 54, a transducer 602 is affixed to an
exposed side of the transduction portion 594, and configured to
operate in a transverse resonant mode "T.sub.1" perpendicular to
the plane of the waveguide 590. No transducer is affixed to the
opposite exposed side of the transduction portion 594. A proximal
portion of the transduction portion 594 is fixed against vibration,
e.g., by a handpiece mount M, at a longitudinal distance, d, from
the center of mass of the transducer 602. Operation of the
transducer 602 creates an intermediate or stack anti-node 533 at
the center of mass of the transducer 602, and a transverse mode of
vibration "T.sub.2" out of the plane of the waveguide 590.
Variation of the longitudinal distance d will vary the frequency of
the resonant mode of vibration, i.e., the wavelength of the
standing wave. In a modification of the first construction, a large
end mass 640 is affixed to the first resonator or proximal end
portion 592 to create a virtual node 534 due to the resistance of
the large rest mass to displacement. Varying the longitudinal
separation of the centers of mass of the transducer 602 and the end
mass 640 will vary the frequency of the resonant mode of
vibration.
[0159] In a second variation of the fourth construction, shown in
FIG. 55, a first transducer 602 is affixed to an exposed side of
the transduction portion 594, and a second transducer 602 is
affixed to an opposite exposed side of the transduction portion
594. The centers of mass of the first and second transducers 602
are separated by a longitudinal distance, d, and configured to
operate in a transverse resonant mode "T.sub.1" perpendicular to
the plane of the waveguide 590, with the first transducer 602 180
degrees out of phase with the second transducer 602. Operation of
the transducers creates a transverse mode of vibration "T.sub.2"
out of the plane of the waveguide 590, as well as a node between
the first and second transducers at d/2. Variation of the
longitudinal distance d will vary the frequency of the resonant
mode of vibration, i.e., the wavelength of the standing wave, as
well as the amplitude of the mode of vibration.
[0160] In a third variation of the fourth construction, shown in
FIG. 56, a first transducer 602 is affixed to the transduction
portion 594 adjacent to one edge 594a of the transduction portion,
and a second transducer 602 is affixed to the transduction portion
594 adjacent to the opposite edge 594b of the transduction portion,
with the first and second transducers being separated by the
central longitudinal axis of the waveguide 590. The first and
second transducers 602 are configured to operate in a
longitudinally-oriented shear mode "LS" where the first transducer
602 is 180 degrees out of phase with the second transducer 602.
Operation of the transducers creates a primary transverse mode of
vibration "T.sub.3" within the plane of the waveguide 590, and a
secondary longitudinal mode of vibration "T.sub.4."
[0161] In implementations of the second expression, the transducer
602 may be configured as a multi-element piezoelectric,
electrostrictive, or, in some instances, magnetostrictive
transducer stack. A multi-element transducer stack, in general,
increases the power and amplitude of the modes of vibration created
within the waveguide. A magnetostrictive transducer is preferably
configured as a multi-element transducer stack in order to reduce
eddy current losses during magnetic excitation. It is to be
understood that references to an ultrasound transducer 602, with
respect to the fifth embodiment in particular and to combinations
with other embodiments or known devices generally, are intended to
include both a transducer configured as a single element transducer
and a transducer configured as a multi-element transducer
stack.
[0162] In a fifth construction of the second expression, shown in
FIGS. 57A and 57B, the transduction portion 594 is configured to
have at least one electrical contact 612 disposed on an exposed
side of the transduction portion 594, and the transducer 602 is
configured to have an electrode portion 608 for surface mount
electrical connection to the electrical contact 612, with the
electrode portion 608 electrically joined to the electrical contact
612 by a solder or braze 601. The electrical contact 612 and
transduction portion 594 may be configured as previously described,
however in this construction the electrical contact may be disposed
adjacent to or even under the transducer 602, which, rather than
being directly bonded to the transduction portion 594, is
indirectly bonded to the transduction portion through at least the
electrode portion 608. The transducer 602 may also be bonded to the
transduction portion 594 with an epoxy or other adhesive for
mechanical stability. The electrode portion 608 may have a similar
construction to that of the electrical contact 612, with, for
example, a nickel pad 607 and a gold top coat 609. As shown in the
figures, an opposing electrode portion 608 may be formed upon the
opposite side of the transducer 602, and an electrical source such
as a wire or shim 619 may be soldered or brazed to the exposed side
of the transducer 602 and opposing electrode portion 608. In a
variation of this construction, an acoustically isolating mount
655, e.g., an o-ring or elastomeric stand-off mount, abuts the side
of transducer structure and may be used instead of soldering to
clamp a shim 619 against the opposing electrode portion 608, or in
addition to soldering for the more limited purpose of mounting the
ultrasonic core within a housing 650 (not shown in these
figures).
[0163] In a second variation of the fifth construction, shown in
FIGS. 58A and 58B, the transduction portion 594 is configured to
have first 632a and second 632b generally linear arrays of
electrical contacts 612 disposed on an exposed side of the
transduction portion 594. The first array 632a is electrically
connected to a furst remote electrical contact 612 which is
electrically connectable to an electric source, and the second
array 632b is electrically connected to a second remote electrical
contact 612 which is electrically connectable to ground. The
electrical connections may be the embedded paths discussed above,
or may be surface traces of a conductive material overlaying an
oxygen rich surface layer, e.g., silicon dioxide (SiO.sub.2). Such
surface traces may be formed by screen printing techniques using
materials such as DuPont 7723, a low-temperature firing silver ink
suitable for printing on glass. The transducer 602 is configured as
a multi-element transducer stack having first 608a and second 608b
generally linear arrays of electrode portions 608 projecting from
stack electrodes disposed between every element of the stack, with
the first 608a and second 608b arrays being alternatingly connected
to successive stack electrodes through the stack. The first 608a
and second 608b arrays of the transducer 608 are configured for
surface mount electrical connection to the first 632a and second
632b arrays of electrical contacts 612, respectively, with the
individual electrode portions 608a and 608b electrically joined to
corresponding individual electrical contacts 612 by a braze 601. In
an exemplary configuration shown in FIGS. 58A and 58B, the
transducer stack is longitudinally oriented, and may operate in a
longitudinal extension mode (d.sub.33) to generate a longitudinal
standing wave in the waveguide 590.
[0164] In other variations of the fifth construction, illustrated
in FIGS. 59A and 59B, the transduction portion 594 may be
configured to have a first plurality of source electrical contacts
632c and a second plurality of ground electrical contacts 632d.
Both pluralities 632c and 632d may be disposed on an exposed side
of the transduction portion 594, with the first plurality 632c
being electrically connectable to an electric source and the second
plurality 632d being electrically connectable to an electric
ground. The transducer 602 is again configured as a multi-element
transducer stack having a first plurality of source electrical
contacts 608c, electrically connected to the elements of the stack
to supply power, and a second plurality of ground contacts 608d,
electrically connected to the elements of the stack to provide
ground. The first 608c and second 608d pluralities of contacts of
the transducer stack may project from the transducer stack, may be
disposed upon the ends and/or edges of the transducer stack, or a
combination of foregoing, and provide terminal legs or pads for
bonding to the first plurality 632c and second plurality 632d of
electrical contacts 632c of the transduction portion 594,
respectively. For example, as illustrated in FIG. 59B, the first
plurality 608c (not visible in the view) and second plurality 608d
of contacts may be metallic strips projecting from the main body of
each electrode 608 and along the ends of the transducer stack 602.
Each strip may form a terminal pad for bonding to a corresponding
one for the first plurality 632c (not visible in the view) and
second plurality 632d of electrical contacts, which may take the
form of electrical contacts 612 or other forms of surface mount
pad. Those portions of the strips not constituting the terminal pad
may be affixed to the transducer stack by a non-conductive
adhesive, formed on or deformed against the transducer stack over
an insulating coating, coated with an insulating coating and
subsequently deformed against the transducer stack, etc. In the
exemplary configuration shown in FIGS. 59A and 59B, the transducer
stack is laterally oriented out of the plane of the waveguide 590,
and may operate in a longitudinal extension mode (d.sub.33, with
respect to the electrode arrangement) in order to `squeeze` the
transduction portion 594 and generate a longitudinal move of
vibration "T.sub.4" in the waveguide 590.
[0165] In a third expression of the fifth embodiment, shown in
FIGS. 60-66, an end mass 640 is affixed to the first resonator 592
of the waveguide 590. In a first construction of the third
expression, shown in FIGS. 60 and 61, the first resonator 592
includes at least one aperture 593 and the end mass 640 includes at
least one corresponding aperture 643. The corresponding apertures
593 and 643 are axially aligned and receive a compressive fastener
620, such as a bolt or rivet. As illustrated in FIG. 61, multiple
end masses 640 may be affixed to the first resonator 592 by the
same compressive fastener 620.
[0166] In a second construction of the third expression, shown in
FIG. 62, the sides of the first resonator 592 include teeth 644
with substantially inclined proximal surfaces 644a and
substantially perpendicular distal surfaces 644b. The end mass 640
includes a channel 642 configured to receive the first resonator
592 and teeth 646 with substantially vertical proximal surfaces
646a and substantially inclined distal surfaces 646b corresponding
to inclined proximal surfaces 644a. Teeth 644 and 646 essentially
irreversibly and interlockingly mesh when channel 642 receives
first resonator 592. The second construction may be used to
compress the transducers 602 as the transducers are formed, or to
place pre-formed transducers under compression after they have been
affixed to the transduction portion 594 of the waveguide 590.
[0167] In a third construction of the third expression, shown in
FIGS. 63 and 64, the end mass includes a channel 642 configured to
receive the first resonator 592, and is indirectly bonded to the
first resonator 592 by an adhesive or braze 601. In variations of
the first through third constructions, the first resonator 592 is a
laminated structure having a lumen 531, for example, the top
structure shown in FIG. 34, and the end mass has a correspondingly
positioned lumen 647. The lumen 647 may communicate with a fitting
648, e.g., a luer fitting, on the proximal end of the end mass 640
to permit fluids or other matter to be introduced and/or withdrawn
through the lumens 647 and 531.
[0168] In some implementations of the constructions of the third
expression, the distal end of the end mass 640 may abut a
transducer 602. Structures such as the aperture 593 of the first
resonator 592 may be configured to require the end mass 640 to
longitudinally compress the transducer 602. Structures such as the
teeth 644 and 646 of the first resonator 592 and end mass 640 may
mechanically lock the end mass 640 into longitudinal compression
with the transducer 602. Finally, first resonator 592 and channel
642 of end mass 640 may be dimensioned such that end mass 640 may
be bonded to first resonator while end mass is longitudinally
compressing the transducer 602. Once the adhesive has cured or the
braze has cooled, the ultrasound transducer 602 remains residually
compressed by the established bond between the first resonator 592
and the end mass 640.
[0169] In other implementations of constructions of the third
expression, shown in FIGS. 65 and 66, the end mass 640 may be
proximally spaced apart from the transducer 602. In particular, end
mass 640 may be spaced apart from the transducer 602 and sized
and/or fixed into place so as to function as a virtual node in the
designed, or principal, mode of vibration of the ultrasonic core.
End mass 640 is preferably manufactured from a high density
material, such as 316 stainless steel, titanium, or aluminum and,
optionally, fixed within and with respect to an instrument housing
650 so as to enhance its function as a virtual node. In such
implementations, the end mass 640 creates a virtual node 534
proximate the first resonator 592 of the waveguide 590, one or more
transducers 602 are disposed at an intermediate or stack anti-node
533 in the transduction portion 594 of the waveguide, and an
acoustically isolating mount 655, e.g., an o-ring, is disposed at a
distal node 536 of the waveguide 590. The distal node 536 may
disposed proximate the distal end of the second resonator 596 or
may be disposed within a connecting portion of the end effector
620a, such as an ultrasonically active shaft portion 528, which is
shown as a monolithically coupled portion of the waveguide. The
relative spacing between the virtual node 534, intermediate
anti-node 533, and distal node 536 establish a primary frequency
(or wavelength) for the mode of vibration, but those of skill in
the art will appreciate that the transducer(s) 602 may be operated
at harmonics of this primary frequency in order to achieve a
desired balance between the length of the instrument housing 650
and the frequency of the resonant mode of vibration transmitted to
the end effector 620a.
[0170] As further illustrated in FIGS. 65 and 66, in an exemplary
instrument for shear-thinning a dermal filler and/or deep tissue
dissection, the instrument housing 650 may include a sheath 657
projecting over the end effector 520a to protect patient tissue at
an insertion entry point. As shown, the sheath 657 may be a rigid,
generally annular, and concentrically mounted sheath projecting
over ultrasonically active portions of the end effector 520a
proximal of its distal-most end. However, those of skill in the art
will recognize that the sheath 657 could instead be longitudinally
flexible, creased sheath, such as the one shown in FIG. 25, so as
to function similarly to the sheaths of the fourth embodiment. In
such constructions, the sheath may be removably mounted to the
distal end of the instrument housing 650 so as to be disposable or
so as to allow differing extents of the distal-most end of the end
effector 520a to be exposed. Alternately, the sheath 657 could
instead be configured similarly to the sheath 446 of the fourth
embodiment, with a proximally adjoining sheath segment, or the
instrument housing 650 itself, providing a spring-biased mechanism
configured to normally bias the sheath 657 distally from the
adjoining sheath segment or housing. The sheath 657 may then
compress to expose proximal portions of the end effector upon
abutting against tougher patient tissues, such as muscle fascia or
cartilage, while protecting overlying subcutaneous fat or dermal
layers alongside the insertion track. The lumens 531 and 647, as
first introduced above, may be used to introduce dermal fillers,
irrigation fluids, and the like, and/or to provide suction in the
operating field during a procedure.
Other Exemplary Configurations and Applications
[0171] FIG. 67 illustrates an exemplary ultrasonic surgical
instrument 700 functioning as an ultrasonic hemostatic forceps. The
instrument 700 includes a longitudinally elongated, generally
planar waveguide 590, constructed from a single crystal or
polycrystalline material, and a transducer structure 600 affixed to
the transduction portion 594 the waveguide at a node 534, i.e., a
stack node 535. The distal end of the waveguide 590 may include an
end effector 520a configured to provide a generally blunt side
surface 521 for the coaptation of patient tissue, with the distal
end and blunt side surface being positioned at a distal-most
anti-node 538. At least the transduction portion 594 of the
waveguide 590 and the transducer structure 600 are mounted within
an instrument housing 650. The mounting may include a first
acoustically isolating mount 651, e.g., an o-ring, disposed about
the waveguide 590 at a proximal-most node, e.g., node 534, and a
second acoustically isolating mount 655 disposed about the
waveguide at distal node 536. As illustrated, the transducer
structure 600 is disposed at the proximal-most node 534 and the
acoustically isolating mount 651 is also disposed about that
transducer structure, however those of skill in the art will
recognize that acoustically isolating mount 651 need not
necessarily be disposed about the transducer structure 600, but may
instead be disposed about the first resonator 592 of the waveguide
590, with the transducer structure 600 affixed to the transduction
portion 594 at more distally located stack node.
[0172] The instrument 700 further includes a longitudinally
elongated and flexible tine 670 projecting from the instrument
housing 650 and extending alongside the waveguide 590. The flexible
tine 670 is preferably a generally arcuate member configured to
distally converge towards the waveguide 590, but it will be
appreciated that the tine may be a linearly segmented member, a
generally straight member substantially spaced apart from the
waveguide 590 at the member's proximal end (so as not to proximally
diverge away from the waveguide 590 before distally converging
toward the waveguide), an arcuate member substantially spaced apart
from the waveguide 590 at the member's proximal end (so as not to
proximally diverge away from the waveguide 590 before distally
converging toward the waveguide), etc. The flexible time 670 has a
tissue pad 672 opposing the blunt side surface 521 of the end
effector 520a, and may include an integrally formed or affixed
finger pad 673 disposed proximate an intermediate node 535. The
housing may further include an integrally formed or affixed finger
pad 653 disposed proximate the node 535. Thus, manipulation of the
instrument housing 650 and tine 670, or fingerpads 653, 673 where
present, may draw together and compress the blunt side surface 521
against the tissue pad 672, permitting the ultrasonic coaptation of
patient tissue. Advantageously, the simplified construction,
reduced size, and reduced expense allowed by constructions using,
e.g., a silicon waveguide 590, permit the forceps surgical
instrument 700 to be disposable without requiring mounting upon
larger ultrasonic instruments, which may prove unwieldy in
ultrasonic microsurgery, and without requiring the cleaning and
sterilization of complicated end effector attachment
mechanisms.
[0173] FIGS. 68 and 69A-C illustrate an exemplary ultrasonic core
800 for an ultrasonic surgical instrument including an end effector
520a configured to function as an ultrasonic tissue ablator. The
core 800 includes a longitudinally elongated, generally planar
waveguide 590, constructed from a single crystal or polycrystalline
material, and a transducer structure 600 affixed to the waveguide.
The distal end of the waveguide 590 includes or is configured to
provide an end effector 520a having a composite distal tip 522
which is constructed from a dissimilar metallic, glassy,
polycrystalline, or crystalline material. The dissimilar material
may be selected to provide enhanced durability, ductility, or
toughness (as determined by ASTM E1820) in comparison to the
waveguide material, and improve resistance to crack propagation in
comparison to the base material. For example, for a silicon
waveguide 590, the distal tip 522 may be principally comprised of a
metal, such as titanium, aluminum, or known surgical alloys, which
are relatively ductile in comparison to the bulk material of the
waveguide 590. For further example, the distal tip 522 may be
principally comprised of a glassy material such as amorphous
silicon or a polycrystalline material such as polycrystalline
silicon (also called polysilicon). In comparison to single crystal
silicon, such materials have substantially enhanced toughness and
crack resistance. For yet further example, the distal tip may be
principally comprised of a polycrystalline or single crystal
sapphire, which is comparatively tougher (in the sense of its
ability to absorb energy and plastically deform without fracturing)
than the silicon or germanium waveguide materials discussed in the
fifth embodiment.
[0174] At least the end effector 520a, and preferably the waveguide
590, is a laminated structure including a plurality of planar
layers, e.g., 590a, 590b, etc., of the material. The distal tip 522
includes a neck or tang 524 which projects proximally of the distal
tip for embedment within the end effector 520a or end effector
portion of the waveguide 590. As shown in FIG. 68A, the neck or
tang 524 may be tapered its proximal end and secured within a
complementary socket 598a configured to receive it. Such a socket
may be formed by etching two adjoining layers of base material,
e.g., 590a and 590b, to define a proximally tapering blind channel,
or other internal void, at each layer's distal-most end, and the
neck or tang 524 may be secured to the adjoining layers as
described below. Alternatively, as shown in FIG. 68B, the neck or
tang 524 may generally planar with generally perpendicular,
proximal abutment wall that is secured to end a complementary
socket 598b configured to receive it. Such a socket may be formed
by etching two adjoining layers of base material, e.g., 590a and
590b, to define a longitudinal blind channel, or other internal
void, at their distal-most ends, or by etching or otherwise cutting
a socket void in an intermediate layer 590d and laminating
adjoining layers 590c and 590e over it, and the neck or tang 524
may be secured to at least one layer (e.g., 590d, or 590a and 590b)
as described below. In a variation these constructions, shown in
FIG. 68C, the neck or tang 524 may be a full width tang, and
constitute the entire distal portion of an intermediate layer 590d
in a composite end effector 520a or end effector portion of the
waveguide 590. The connection may be formed by foreshortening or
removing a distal end of the intermediate layer 590d, and
laminating adjacent layers, e.g., a first adjacent layer 590c and a
second adjacent layer 590e, to opposite sides of the intermediate
layer 509d and tang 524. In such constructions, the neck or tang
524 may be secured via brazing (using materials such as those
disclosed in Table 1), via an adhesive layer (such as a urethane
acrylate, cyanoacrylate, or epoxy), or via direct bonding, such as
that resulting from various silicate silicon-to-sapphire bonding
processes known in the semiconductor manufacturing arts. Where
brazing is used, the material is preferably a tungsten or gold
eutectic braze so as to provide a strong but low impedance acoustic
joint between the materials.
[0175] FIG. 70 illustrates another exemplary ultrasonic core 900
for an ultrasonic surgical instrument 900. The core 900 includes a
longitudinally elongated, generally planar waveguide 590,
constructed from a single crystal or polycrystalline material, and
a transducer structure 600 affixed to the waveguide. However, the
core 900 also further includes an additional longitudinally
elongated, generally planar waveguide 590', constructed from the
same material, affixed to an opposite side of the transducer
structure 600 to form a mutually opposing pair of spaced apart
waveguides 590, 590'. The waveguides 590, 590' each include an end
effector 520a, 520a' projecting beyond a spacer 655' disposed
between the waveguides at a distal node 536 to form mutually
opposing tines in a coherent interference end effector. The distal
node is preferably a distal-most node 537, with the distal ends of
the end effectors 520a, 520a' being disposed at a distal-most
anti-node 538. Additional spacers 655' may be also disposed at
other distal nodes 536 in order to maintain adequate separation of
the waveguides 590,590'.
[0176] The transducer structure is configured to operate in a
transverse resonant mode "T.sub.1" perpendicular to the planes of
the waveguides 590, 590'. As a result, contraction of the
transducer material will pull transduction portion 594 of each
waveguide toward the other, and expansion of the transducer
material will push the transduction portion of each waveguide away
from each other. This transverse ultrasonic vibration of the
waveguides 590, 590' will be replicated, neglecting the effects of
ultrasonic gain produced in a distal resonator 596 or the like, in
the projecting ends of the end effectors 520a, 520a' at a
distal-most anti-node 538. Since the two waveguides 590, 590a' are
driven at the same resonant frequency by the transducer structure
600, the transverse ultrasonic vibration will be coherent and,
considering one mutually opposing tine with respect to the other,
180.degree. out-of-phase so as to cause constructive interference
at least in the space between the mutually opposing tines. This
constructive interference enhances tissue friction and heating
between the mutually opposing tines, allowing for the use of
smaller, less powerful transducer structures and also enhancing the
frictional heating of tissue surrounding the mutually opposing
tines.
Transducer-to-Waveguide Coupling
[0177] Implementations of the fifth embodiment may be substantially
smaller, more compact, less mechanically complex, and less
expensive due to the transducer-on-planar-waveguide construction,
polycrystalline or single crystal material base, alternate means of
affixing and electrically connecting transducer structures, and
other features discussed above. However, these constructions tend
to have narrow phase margins and tend to be subject to rapid shifts
in system modal frequency when applied to loads such as patient
tissues. As a result, the relative positioning and dimensions of
the transducer structure relative to the longitudinally elongated,
generally planar waveguide have been found to have a substantial
effect upon the ability of such devices to drive power into patient
tissues, dermal fillers, acoustic coupling fluids, and the like
without generating excessive latent or waste heat or causing the
system modal frequency to shift (both in terms of frequency and
rapidity of frequency shift) in a manner which cannot reasonably be
tracked by a ultrasound generator powering the ultrasonic core.
[0178] In a fourth expression of the fifth embodiment, an
ultrasonic core such as that illustrated in FIG. 71, the transducer
structure 600 affixed to the transduction portion 594 has a first
length, L.sub.1, and the transduction portion 594, or the
combination of the first or proximal resonator 592 and transduction
portion 594 where the former is included, has a second longitudinal
length, L.sub.2. The second or distal resonator 596, has a proximal
end 596a, generally distinguished by a change in geometry near a
node 534 (most typically, the start of reduction in transverse
extent, e.g., width w, where w decreases from w.sub.p), and a
distal end 596b, generally distinguished by a cessation in the
change in geometry near more distal node 534 (most typically, the
start of a section of constant transverse extent, e.g., width w,
where w remains equal to w.sub.d), and a length, L.sub.3, between
proximal end 596a and distal end 596b. Accordingly, transducer
structure 600 may be separated from proximal end 596a of the distal
resonator 596 by a distal margin indicated by L.sub.dm. As
indicated in FIG. 71, the transduction portion 594 and any first or
proximal resonator typically have a first lateral extent, a distal
end or end effector portion of the waveguide typically has a
second, narrower lateral extent, with the second or distal
resonator 596 transitioning from the first lateral extent (i.e.,
w.sub.p) to the second lateral extent (i.e., w.sub.d) in one of the
manners described a first expression of the fifth embodiment above.
In a preferred exemplary construction of the illustrated device,
the length L.sub.2 is 40 mm, the length L.sub.3 is 20 mm, the first
lateral extent (corresponding to w.sub.p) is 10 mm, and the second
lateral extent (corresponding to w.sub.d) is 2.5 mm. In the
preferred construction and illustration the waveguide 590,
including a distal end effector portion 520a having a distal-most
anti-node 538, has an overall length of 70 mm; however, those of
skill in the art will appreciate that length of the waveguide 590
distal from the distal resonator may be varied, e.g., by adding
half-wavelength lengths to the distal end effector portion 520a,
without substantially varying the design rules and relative
dimensions discussed below. A DOE model was constructed for the
preferred construction with a transitional catenary shaped distal
resonator 596, where the width of the distal resonator 596 from
proximal end 596a to distal end 596b is describable by:
w ( l ) = w d ( cosh ( .alpha. ( L 3 - l ) ) ) 2 , .alpha. = 1 L 3
cosh - 1 ( w p w d ) ( 1 ) ##EQU00001##
and 1 ranges from 0 at the proximal end 596a to L.sub.3 at the
distal end 596b. This DOE model was subsequently used to test
design rules discussed in the constructions presented below.
[0179] In a first construction of the fourth expression, the ratio
of the length of the transduction portion 594 and any proximal
resonator 592 to the length of the transducer structure 600 should
be less than or equal to 1.8:1, i.e., the transducer structure 600
should be at least half as long as the length of waveguide 790
proximally from the distal resonator 596. As shown in FIG. 72, the
ANOVA component effect of the length of transducer 602 upon the
acoustic gain of the waveguide 590 is negative (so as to decrease
or suppress acoustic amplitude) for ratios greater than 1.8:1,
i.e., for transducers 602 with lengths less than 22 mm in the
preferred construction, but becomes increasingly positive for
ratios less than 1.8:1. As indicated in FIG. 73, such a ratio also
serves to minimize the acoustic impedance of the connection between
the transducer 602 and the waveguide 590, but only for ratios
greater than or equal to 1.4:1. Thus, it is particularly preferred
that the ratio of the length of the transduction portion 594, and
any proximal resonator 592, to the length of the transducer
structure 600 is both less than or equal to 1.8:1 and greater than
or equal to 1.4:1.
[0180] In a second and related construction of the fourth
expression, the difference between an modal frequency of the
ultrasonic core, i.e., the system modal frequency, f.sub.sys, of
the transducer structure, waveguide 590, and any distal end
effector 520a, and an intrinsic modal frequency of the transducer
structure 600 itself, i.e., the intrinsic transducer modal
frequency, f.sub.trans, should be no less than 15 percent and no
greater than 32 percent of the total system modal frequency,
i.e:
0.15 .ltoreq. f sys - f trans f sys .ltoreq. 0.32 ( 2 )
##EQU00002##
As indicated in FIGS. 73 and 74, such a difference serves to
maximize the phase peak of the ultrasonic core while minimizing the
acoustic impedance of the connection between the transducer
structure 600 and the waveguide 590.
[0181] In a third and related construction of the fourth
expression, the distal margin between a distal end of the
transducer structure 600 and proximal end 592a the distal resonator
592 should be no less than 14 percent and no more than 34 percent
of the length of the transduction portion 594 and any proximal
resonator 592, i.e.:
0.14 .ltoreq. L d m L 2 .ltoreq. 0.34 ( 3 ) ##EQU00003##
As indicated in FIG. 75, this margin affects the drivable load and
may be altered by altering either the length of the transducer
structure 600 or the positioning of the transducer structure on the
transduction portion 594 of the waveguide 590.
[0182] The reader will appreciate that the design rules discussed
in the first through third constructions of the fourth expression
are to some extent related to each other, such that other
constructions may employ subcombinations or a complete combination
of these considerations. In a first variation of the preferred
exemplary construction introduced above, the transducer structure
600 has a length, L.sub.1, of 30 mm and is centered 15 mm from the
proximal end of the waveguide, such that there is essentially no
proximal resonator, the ratio of the length of the transduction
portion 594 to the length of the transducer structure 600 is
1.33:1, the modal frequency separation is about 23%, and the distal
margin is 10 mm, or 25%, of the length of the transduction portion
594 (L.sub.2). In a second variation of the preferred exemplary
construction, the transducer structure has a length, L.sub.1, of 27
mm and is centered 20 mm from the proximal end of the waveguide,
such that the ratio of the length of the transduction portion 594
to the length of the transducer structure 600 is about 1.5:1, the
modal frequency separation is about 23%, and the distal margin is
6.5 mm, or about 16%, of the length of the transduction portion 594
combined with the proximal resonator 592 (combined, L.sub.2). With
regard to system modal frequency and intrinsic transducer modal
frequency, the waveguide 590 was modeled as planar silicon
structure which was 1 mm thick and the transducer structure 600 was
modeled as a rectangular, PZT-8 transducer which was 10 mm wide and
2 mm thick, yielding a system modal frequency
f.sub.sys.apprxeq.82.5 kHz and an intrinsic transducer modal
frequency f.sub.trans.apprxeq.63.8 kHz for the first variation, and
a system modal frequency f.sub.sys.apprxeq.74.8 kHz and an
intrinsic transducer modal frequency f.sub.trans.apprxeq.57.7 kHz
for the second variation. Each variation of the exemplary
construction exhibits good acoustic gain and ability to deliver
power into a load, as well as minimal acoustical impedance at the
connection between transducer structure 600 and waveguide 590.
[0183] While the present invention has been illustrated by
description of several embodiments, it is not the intention of the
applicant to restrict or limit the spirit and scope of the appended
claims to such detail. Numerous variations, changes, and
substitutions will occur to those skilled in the art without
departing from the scope of the invention. Moreover, the structure
of each element associated with the present invention can be
alternatively described as a means for providing the function
performed by the element. Accordingly, it is intended that the
invention be limited only by the spirit and scope of the appended
claims.
* * * * *