U.S. patent application number 17/096932 was filed with the patent office on 2021-03-11 for rapid pulse electrohydraulic (eh) shockwave generator apparatus and methods for medical and cosmetic treatments.
The applicant listed for this patent is Board of Regents, The University of Texas System, Soliton, Inc.. Invention is credited to Christopher C. CAPELLI, Robert CROWLEY.
Application Number | 20210069529 17/096932 |
Document ID | / |
Family ID | 1000005237257 |
Filed Date | 2021-03-11 |
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United States Patent
Application |
20210069529 |
Kind Code |
A1 |
CAPELLI; Christopher C. ; et
al. |
March 11, 2021 |
RAPID PULSE ELECTROHYDRAULIC (EH) SHOCKWAVE GENERATOR APPARATUS AND
METHODS FOR MEDICAL AND COSMETIC TREATMENTS
Abstract
Apparatuses and methods for electrohydraulic generation of
shockwaves at a rate of between 10 Hz and 5 MHz, and/or that permit
a user to view a region of a patient comprising target cells during
application of generated shockwaves to the region. Methods of
applying electro-hydraulically generated shockwaves to target
tissues (e.g., for reducing the appearance of tattoos, treatment or
reduction of certain conditions and/or maladies).
Inventors: |
CAPELLI; Christopher C.;
(Houston, TX) ; CROWLEY; Robert; (Sudbury,
MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Soliton, Inc.
Board of Regents, The University of Texas System |
Houston
Austin |
TX
TX |
US
US |
|
|
Family ID: |
1000005237257 |
Appl. No.: |
17/096932 |
Filed: |
November 12, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14773568 |
Sep 8, 2015 |
10857393 |
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PCT/US14/21746 |
Mar 7, 2014 |
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17096932 |
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13798710 |
Mar 13, 2013 |
10835767 |
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14773568 |
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61775232 |
Mar 8, 2013 |
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61775232 |
Mar 8, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61N 7/00 20130101; A61B
2090/3616 20160201; A61B 2017/00769 20130101; A61B 17/225 20130101;
A61N 2007/0034 20130101; A61N 2007/0013 20130101; A61N 2007/0008
20130101 |
International
Class: |
A61N 7/00 20060101
A61N007/00 |
Claims
1. An apparatus associated with generation of therapeutic shock
waves, the apparatus comprising: a spark housing configured to be
removably coupled to a probe, the spark housing including: a body
that defines a chamber having a shockwave outlet, the chamber
configured to be filled with a liquid; a first connector coupled to
the body and configured to be electrically coupled to the probe via
a second connector of the probe; and a plurality of electrodes
disposed in the chamber and configured to define one or more spark
gaps, at least one electrode of the plurality of electrodes
electrically coupled to the first connector; where the spark
housing is removable from the probe as a single unit that includes
the body, the first connector, and the plurality of electrodes.
2. The apparatus of claim 1, where the spark housing comprises a
spark head and a first housing coupled to the spark head.
3. The apparatus of claim 2, where: the spark head defines a first
portion of the chamber; and the first housing defines a second
portion of the chamber, the first portion and the second portion
cooperate to define the chamber.
4. The apparatus of claim 2, where spark head is permanently
adhered to the first housing.
5. The apparatus of claim 1, where the spark housing further
includes a first liquid connector in fluid communication with the
chamber, the first liquid connector configured to be coupled to a
conduit of the probe to enable circulation of the liquid.
6. The apparatus of claim 5, further comprising: the probe
including a first plurality of electrical connectors associated
with the second connector of the probe and configured to be coupled
to a pulse-generation system; and where, the spark housing further
includes a second plurality of electrical connectors associated
with the first connector of the spark housing and configured to be
electrically coupled to the first plurality of electrical
connectors of the probe.
7. The apparatus of claim 5, further comprising: the probe
including: a handle portion; a high voltage connector positioned on
the handle portion and coupled to a pulse-generation system; and
where the spark housing is configured to be couple to the
pulse-generation system via the probe.
8. The apparatus of claim 5, where the plurality of electrodes
include a first electrode and a second electrode moveable relative
to the first electrode, the first electrode and the second
electrode defining a first spark gap of the one or more spark
gaps.
9. The apparatus of claim 8, where, when the chamber is filled with
the liquid and the spark housing is coupled to a pulse-generation
system, the plurality of electrodes are configured to receive
voltage pulses from the pulse-generation system via the first and
second connectors such that portions of the liquid are vaporized to
generate therapeutic shockwaves that propagate through the liquid
and out the shockwave outlet.
10. An apparatus associated with generation of therapeutic
shockwaves, the apparatus comprising: a spark housing configured to
be removably coupled to a hand-held probe, the spark housing
comprising: a body defining a chamber and having: a first end that
defines an outlet of the chamber; and a second end that is opposite
the first end, the second end configured to be removably coupled to
the probe; at least two electrodes disposed within the chamber, the
at least two electrodes defining a first spark gap configured to
generate one or more shockwaves that propagate through the chamber
and out of the outlet; and a first electrical connector coupled to
the body and configured to be electrically coupled to one or more
second electrical connectors of the probe; and where the spark
housing is removable from the probe as a single unit that includes
the body, the first electrical connector, and the at least two
electrodes.
11. The apparatus of claim 10, where when the chamber is filled
with liquid and the spark housing is coupled to a pulse-generation
system, the at least two electrodes are configured to receive
voltage pulses from the pulse-generation system via the first and
second electrical connectors such that portions of the liquid are
vaporized to generate therapeutic shockwaves that propagate through
the liquid and to the outlet.
12. The apparatus of claim 10, where the spark housing further
includes a cap member coupled to the first end of the body.
13. The apparatus of claim 11, where the second end of the body
defines a channel configured to be in communication with the probe
while the spark housing is coupled to the probe.
14. The apparatus of claim 13, where the at least two electrodes
are aligned with the channel.
15. The apparatus of claim 13, where the spark housing further
includes a first liquid connector in fluid communication with the
chamber, the first liquid connector configured to be coupled to a
conduit of the probe to enable circulation of the liquid within the
chamber.
16. The apparatus of claim 11 further comprising: the probe
including: a handle portion; a high voltage connector positioned on
the handle portion and coupled to the pulse-generation system; the
second electrical connector coupled to the handle portion; and
where the spark housing is configured to be coupled to the
pulse-generation system via the probe.
17. A method comprising: generating a plurality of shockwaves, via
a plurality of electrodes disposed within a chamber of a first
spark housing, the first spark housing including: a body defining
the chamber and having: a first end that defines a shockwave outlet
of the chamber; and a second end that is opposite the first end,
the second end configured to be removably coupled to a handheld
probe; the plurality of electrodes disposed within the chamber, the
plurality of electrodes defining a first spark gap; and a first
electrical connector coupled to the body and configured to be
electrically coupled to one or more second electrical connectors of
the probe; and propagating the plurality of shockwaves through the
chamber and out of the shockwave outlet; where the spark housing is
removable from the probe as a single unit that includes the body,
the first electrical connector, and the plurality of
electrodes.
18. The method of claim 17, further comprising coupling the first
spark housing to the probe.
19. The method of claim 17, further comprising decoupling the first
spark housing from the probe.
20. The method of claim 19, further comprising coupling a second
spark module to the probe, the second spark module including a
second body defining a second chamber, a second plurality of
electrodes coupled to the second body, and a third electrical
connector configured to be electrically coupled to one or more
second electrical connectors of the probe.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. patent
application Ser. No. 14/773,568 filed Sep. 8, 2015, which is a
national phase application under 35 U.S.C. .sctn. 371 of
International Application No PCT/US2014/021746, filed Mar. 7, 2014,
which is a continuation-in-part of U.S. patent application Ser. No.
13/798,710, filed Mar. 13, 2013 which claims priority of U.S.
Provisional Patent Application No. 61/775,232, filed Mar. 8, 2013.
The contents of the above-referenced applications are incorporated
into the present specification by reference.
BACKGROUND
1. Field of the Invention
[0002] The present invention relates generally to therapeutic uses
for shock waves or shockwaves. More particularly, but not by way of
limitation, the present invention relates to an apparatus for
generating therapeutic shock waves or shockwaves (shock waves with
therapeutic uses).
2. Description of Related Art
[0003] Acoustic shockwaves have been used for certain therapies for
a number of years. "Shock wave" or "shockwave" is generally used to
refer to an acoustic phenomenon (e.g., resulting from an explosion
or lightning) that creates a sudden and intense change in pressure.
These intense pressure changes can produce strong waves of energy
that can travel through elastic media such as air, water, human
soft tissue, or certain solid substances such as bone, and/or can
induce an inelastic response in such elastic media. Methods for
creating shock waves for therapeutic uses include: (1)
electrohydraulic, or spark gap (EH); (2) electromagnetic, or EMSE;
and (3) piezoelectric. Each is based upon its own unique physical
principles.
[0004] A. Devices and Systems for Shockwave Generation
[0005] U.S. patent application Ser. No. 13/574,228 (a
national-stage application of PCT/US2011/021692, which published as
WO 2011/091020), by one of the present inventors, discloses a
device for producing shock waves at a high pulse rate using a
transducer. That device includes an acoustic-wave generator
configured to emit acoustic waves having at least one frequency
between 1 MHz and 1000 MHz; a shockwave housing coupled to the
acoustic-wave generator; and a shockwave medium disposed in the
shockwave housing; where the apparatus is configured such that if
the acoustic-wave generator emits acoustic waves then at least some
portion of the acoustic waves will travel through the shockwave
medium and form shock waves. That device can be actuated to form
shock waves configured to cause particles within a patient to
rupture one or more cells of the patient, and the shock waves can
be directed to cells of a patient such that the shock waves cause
particles to rupture one or more of the cells. This
acoustic-transducer device can produce high powered shockwaves at
high frequencies or pulse rates.
[0006] Other systems for producing shockwaves can include an
electrohydraulic (EH) wave generator. EH systems can generally
deliver similar levels of energy as other methods, but may be
configured to deliver that energy over a broader area, and
therefore deliver a greater amount of shock wave energy to targeted
tissue over a shorter period of time. EH systems generally
incorporate an electrode (i.e., a spark plug) to initiate a shock
wave. In EH systems, high energy shock waves are generated when
electricity is applied to an electrode immersed in treated water
contained in an enclosure. When the electrical charge is fired, a
small amount of water is vaporized at the tip of the electrode and
the rapid, nearly instantaneous, expansion of the vaporized water
creates a shock wave that propagates outward through the liquid
water. In some embodiments, the water is contained in an ellipsoid
enclosure. In these embodiments, the shock wave may ricochet from
the sides of the ellipsoid enclosure and converge at a focal point
that coincides with the location of the area to be treated.
[0007] For example, U.S. Pat. No. 7,189,209 (the '209 patent)
describes a method of treating pathological conditions associated
with bone and musculoskeletal environments and soft tissues by
applying acoustic shock waves. The '209 patent describes that
shockwaves induce localized trauma and cellular apotosis therein,
including micro-fractures, as well as to induce osteoblastic
responses such as cellular recruitment, stimulate formation of
molecular bone, cartilage, tendon, fascia, and soft tissue
morphogens and growth factors, and to induce vascular
neoangiogenesis. The '209 patent claims several specific
implementations of its method. For instance, the '209 patent claims
a method of treating a diabetic foot ulcer or a pressure sore,
comprising: locating a site or suspected site of the diabetic foot
ulcer or pressure sore in a human patient; generating acoustic
shock waves; focusing the acoustic shock waves throughout the
located site; and applying more than 500 to about 2500 acoustic
shock waves per treatment to the located site to induce
micro-injury and increased vascularization thereby inducing or
accelerating healing. The '209 patent discloses a frequency range
of approximately 0.5-4 Hz, and application of about 300 to 2500 or
about 500 to 8,000 acoustic shock waves per treatment site, which
can result in a treatment duration for each treatment site and/or a
"total time per treatment" for all sites that is inconveniently
large. For example, the '209 patent discloses total times per
treatment for different examples ranging from 20 minutes to 3
hours.
[0008] U.S. Pat. No. 5,529,572 (the '572 patent) includes another
example of the use of electro-hydraulically generated shockwaves to
produce therapeutic effect on tissues. The '572 patent describes a
method of increasing the density and strength of bone (to treat
osteoporosis), comprising subjecting said bone to substantially
planar, collimated compressional shock waves having a substantially
constant intensity as a function of distance from a shock wave
source, and wherein said collimated shock waves are applied to the
bone at an intensity of 50-500 atmospheres. The '572 patent
describes the application of unfocussed shock waves to produce
dynamic repetitive loading of the bone to increase mean bone
density, and thereby strengthen bone against fracture. As described
in the '572 patent, "the unfocussed shock waves preferably are
applied over a relatively large surface of the bone to be treated,
for example to cover an area of from 10 to 150 cm.sup.2. The
intensity of the shock waves may be from 50-500 atmospheres. Each
shock wave is of duration of a few microseconds, as in a
conventional lithotripter, and is preferably applied at a frequency
of 1-10 shock waves per second for a period of 5-30 minutes in each
treatment. The number of treatments depends on the particular
patient."
[0009] U.S. patent application Ser. No. 10/415,293 (the '293
application), which is also published as US 2004/0006288, discloses
another embodiment of the use of EH-generated shockwaves to provide
a therapeutic effect on tissues. The '293 application discloses a
device, system, and method for the generation of therapeutic
acoustic shock waves for at least partially separating a deposit
from a vascular structure. The '293 application describes that the
device can produce shockwaves at a pulse rate of about 50 to about
500 pulses per minute (i.e., 0.83 to 8.33 Hz) with a number of
pulses per treatment site (in terms of per length of vascular unit
being treated) from about 100 to about 5,000 per 1 cm.sup.2.
[0010] B. Shockwave Rate
[0011] Prior art literature has indicated that faster pulse rates
using EH systems to provide shockwaves can lead to tissue damage.
For example, in one study (Delius, Jordan, & et al, 1988) [2],
the effect of shock waves on normal canine kidneys was examined in
groups of dogs whose kidneys were exposed to 3000 shockwaves. The
groups differed only in the rate of shockwave administration which
was 100 Hz and 1 Hz, respectively. Autopsy was performed 24 to 30
hours later. Macroscopically and histologically, significantly more
hemorrhages occurred in kidney parenchyma if shockwaves were
administered at a rate of 100 Hz (vs 1 Hz). The results showed that
kidney damage is dependent on the rate of shockwave
administration.
[0012] In another study (Madbouly & et al, 2005) [7], slow
shockwave lithotripsy rate (SWL) was associated with a
significantly higher success rate at a lower number of total
shockwaves compared to the fast shockwave lithotripsy rate. In this
paper, the authors discussed how human studies have also shown a
decrease in the incidence of SWL induced renal injury or need for
anesthesia when slower rates of test SWL were used.
[0013] In yet another study (Gillitzer & et al, 2009) [5],
slowing the delivery rate from 60 to 30 shockwaves per minute also
provides a dramatic protective effect on the integrity of real
vasculature in a porcine model. These findings support potential
strategies of reduced pulse rate frequency to improve safety and
efficacy in extracorporeal shockwave lithotripsy.
[0014] C. Tissue as a Viscoelastic Material
[0015] One reason for sensitivity to pulse rate found in the prior
art may be due in part to the relaxation time of tissue. Cells have
both elastic and viscous characteristics, and thus are viscoelastic
materials. Unlike most conventional materials, cells are highly
nonlinear with their elastic modulus depending on the degree of
applied or internal stress. (Kasza, 2007) [6]. One study (Fernandez
(2006) [3] suggests that fibroblast cells can be modeled as a gel
having a cross-linked actin network that show a transition from a
linear regime to power law strain stiffening.
[0016] The authors of another paper (Freund, Colonius, & Evan,
2007) [4] hypothesize that the cumulative shear of the many shocks
is damaging, and that the mechanism may depend on whether there is
sufficient time between shocks for tissue to relax to the
unstrained state. Their viscous fluid model suggested that any
deformation recovery that will occur is nearly complete by the
first 0.15 second after the shock. As a result, their model of the
mechanism for cell damage would be independent of shock rate for
shock rates slower than .about.6 Hz. However, actual
viscoelasticity of the interstitial material, with a relaxation
time about 1 second, would be expected to introduce its sensitivity
to the shock delivery rate. Assuming the interstitial material has
a relaxation time of .about.1 second, the authors would expect
significantly decrease damage for delivery rates lower than
.about.1 Hz. Conversely, damage should increase for faster delivery
rates. Implications of their model are that slowing delivery rates
and broadening focal zones should both decrease injury.
SUMMARY
[0017] Soft tissues may transition from elastic to viscous behavior
for pulse rates (PRs) between 1 Hz and 10 Hz. As a result,
potential damage to tissue from shockwaves at PRs between 1 Hz and
10 Hz is unpredictable when typical lithotripsy power levels are
used. Perhaps as a result, the prior art teaches slower PRs and
large total times per treatment (TTPT). For example, currently
known EH shockwave systems generally deliver PRs of less than 10 Hz
and require large total times per treatment (TTPT) (e.g., TTPT
periods of minutes or even hours for even a single treatment site).
When, as may be typical, a treatment requires repositioning of a
device at multiple treatment sites, the TTPT becomes large and
potentially impractical for many patients and treatment needs.
[0018] While long treatment times may be acceptable for
extracorporeal shockwave lithotripsy, the use of shockwaves to
provide non-lithotripsy therapeutic effects on tissue in the
medical setting is less than optimal if not impractical. For
example, the cost of treatment often increases with the time needed
to administer a treatment (e.g., due to the labor, facilities and
other resource costs allocated to the administration of the
treatment). Furthermore, in addition to costs, at some point the
duration of providing treatment to the patient becomes unbearable
for the patient receiving, and healthcare staff providing, the
treatment.
[0019] This disclosure includes embodiments of apparatuses and
methods for electrohydraulic generation of therapeutic shockwaves.
The present EH-shockwave systems and methods are configured to
deliver shockwaves to tissues to provide a predictable therapeutic
effect on the tissue, such as by delivering shockwaves at higher
(e.g., greater than .about.10 Hz) to reduce TTPT relative to known
systems.
[0020] The present embodiments of electrohydraulic (EH) apparatuses
can be configured to generate high-frequency shock waves in a
controlled manner (e.g., using an electrohydraulic spark generator
and a capacitive/inductive coil spark generating system). The
present pulse-generation (e.g., electrohydraulic spark circuits)
can comprise one or more EH tips and, with the present
capacitive/inductive coil spark generating systems, can produce a
spark pulse rate of 10 Hz to 5 MHz. The shock waves can be
configured to impose sufficient mechanical stress to the targeted
cells of the tissue to rupture the targeted cells, and can be
delivered to certain cellular structures of a patient for use in
medical and/or aesthetic therapeutic applications.
[0021] The present high-pulse rate (PR) shockwave therapies can be
used to provide a predictable therapeutic effect on tissue while
having a practical total time per treatment (TTPT) at the treatment
site. The present high-PR shockwave therapies can be used to
provide a predictable therapeutic effect on tissue, if the
viscoelastic nature of the tissue is considered. Specifically,
shockwave therapy utilizing a PR greater than 10 Hz and even
greater than 100 Hz can be used to provide a predictable
therapeutic effect on tissue because at those PRs the tissue is,
for the most part, predictably viscous in nature and generally does
not vary between elastic and viscous states. Given that tissue
behaves as a viscous material at great enough PRs, the PR and power
level can be adjusted to account for the tissue's viscous
properties. When the viscous nature of the tissue is accounted for
using higher PRs, lower power levels can be used to achieve
therapeutic effects. One benefit of using higher PRs in combination
with lower power levels is the reduction in cavitation formation,
which further improves predictability of the present shockwave
therapies. Embodiments of the present EH apparatuses and methods
can provide targeted rupturing of specific cells without damaging
side effects such as cavitation or thermal degradation of
surrounding non-targeted cells.
[0022] Some embodiments of the present apparatuses (for generating
therapeutic shock waves) comprise: a housing defining a chamber and
a shockwave outlet; a liquid disposed in the chamber; a plurality
of electrodes configured to be disposed in the chamber to define
one or more spark gaps; and a pulse-generation system configured to
apply voltage pulses to the plurality of electrodes at a rate of
between 10 Hz and 5 MHz; where the pulse-generation system is
configured to apply the voltage pulses to the plurality of
electrodes such that portions of the liquid are vaporized to
propagate shockwaves through the liquid and the shockwave
outlet.
[0023] Some embodiments of the present apparatuses (for generating
therapeutic shock waves) comprise: a housing defining a chamber and
a shockwave outlet, the chamber configured to be filled with a
liquid; and a plurality of electrodes disposed in the chamber to
define a plurality of spark gaps; where the plurality of electrodes
is configured to receive voltage pulses from a pulse-generation
system at a rate of between 10 Hz and 5 MHz such that portions of
the liquid are vaporized to propagate shockwaves through the liquid
and the shockwave outlet.
[0024] Some embodiments of the present apparatuses (for generating
therapeutic shock waves) comprise: a housing defining a chamber and
a shockwave outlet, the chamber configured to be filled with a
liquid; and a plurality of electrodes configured to be disposed in
the chamber to define one or more spark gaps; where the plurality
of electrodes is configured to receive voltage pulses from a
pulse-generation system such that portions of the liquid are
vaporized to propagate shockwaves through the liquid and the
shockwave outlet; and where the housing comprises a translucent or
transparent window that is configured to permit a user to view a
region of a patient comprising target cells.
[0025] In some embodiments of the present apparatuses, the
plurality of electrodes are not visible to a user viewing a region
through the window and the shockwave outlet. Some embodiments
further comprise: an optical shield disposed between the window and
the plurality of electrodes. In some embodiments, the plurality of
electrodes are offset from an optical path extending through the
window and the shockwave outlet. Some embodiments further comprise:
an acoustic mirror configured to reflect shockwaves from the
plurality of electrodes to the shockwave outlet. In some
embodiments, the acoustic mirror comprises glass. In some
embodiments, the one or more spark gaps comprise a plurality of
spark gaps. In some embodiments, the plurality of electrodes are
configured to be removably coupled to the pulse-generation system.
In some embodiments, the housing is replaceable.
[0026] Some embodiments of the present apparatuses further
comprise: a spark module comprising: a sidewall configured to
releasably couple the spark module to the housing; where the
plurality of electrodes is coupled to the sidewall such that the
plurality of electrodes is disposed in the chamber if the spark
module is coupled to the housing. In some embodiments, the sidewall
comprises a polymer. In some embodiments, the sidewall of the spark
module is configured to cooperate with the housing to define the
chamber. In some embodiments, the sidewall defines a spark chamber
within which the plurality of electrodes is disposed, the spark
chamber is configured to be filled with a liquid, and at least a
portion of the sidewall is configured to transmit shockwaves from a
liquid in the spark chamber to a liquid in the chamber of the
housing. In some embodiments, the sidewall of the spark module
comprises at least one of pins, grooves, or threads, and the
housing comprises at least one of corresponding grooves, pins, or
threads to releasably couple the spark module to the housing. In
some embodiments, the housing includes a first liquid connector
configured to fluidly communicate with the chamber when the spark
module is coupled to the housing, and the sidewall of the spark
module includes a second liquid connector configured to fluidly
communicate with the chamber when the spark module is coupled to
the housing In some embodiments of the present apparatuses, the
housing further comprises two liquid connectors. Some embodiments
further comprise: a liquid reservoir; and a pump configured to
circulate liquid from the reservoir to the chamber of the housing
via the two liquid connectors.
[0027] In some embodiments of the present apparatuses, the
pulse-generation system is configured to apply voltage pulses to
the plurality of electrodes at a rate of between 20 Hz and 200 Hz.
In some embodiments, the pulse-generation system is configured to
apply voltage pulses to the plurality of electrodes at a rate of
between 50 Hz and 200 Hz. In some embodiments, the pulse-generation
system comprises: a first capacitive/inductive coil circuit
comprising: an induction coil configured to be discharged to apply
at least some of the voltage pulses; a switch; and a capacitor;
where the capacitor and the switch are coupled in parallel between
the induction coil and a current source. In some embodiments, the
pulse-generation system comprises: a second capacitive/inductive
coil circuit similar to the first capacitive/inductive coil
circuit; and a timing unit configured to coordinate the discharge
of the induction coils of each of the first and second
capacitive/inductive coil circuits.
[0028] Some embodiments of the present apparatuses comprise: a
spark module that comprises: a sidewall configured to releasably
couple the spark module to a probe; a plurality of electrodes
disposed on a first side of the sidewall and defining one or more
spark gaps; and a plurality of electrical connectors in electrical
communication with the plurality of electrodes and configured to
releasably connect the electrodes to a pulse-generation system to
generate sparks across the one or more spark gaps. In some
embodiments, the sidewall comprises a polymer. In some embodiments,
the sidewall includes a liquid connector configured to communicate
liquid through the sidewall In some embodiments, the sidewall
defines a spark chamber within which the plurality of electrodes is
disposed, the spark chamber is configured to be filled with a
liquid, and at least a portion of the sidewall is configured to
transmit shockwaves from a liquid in the spark chamber to a liquid
in the chamber of the housing. In some embodiments, the spark
module further comprises one or more liquid connectors in fluid
communication with the spark chamber such that the spark chamber
can be filled with a liquid. In some embodiments, the one or more
liquid connectors comprise two liquid connectors through which a
liquid can be circulated through the spark chamber. In some
embodiments, the sidewall is configured to releasably couple the
spark module to a probe having a chamber such that the electrodes
are disposed within the chamber of the probe. In some embodiments,
the sidewall and the probe cooperate to define the chamber. In some
embodiments, the spark module further comprises one or more liquid
connectors in fluid communication with the chamber of the probe
such that the chamber of the probe can be filled with a liquid
through the one or more liquid connectors. In some embodiments, the
one or more liquid connectors comprise two liquid connectors
through which a liquid can be circulated through the chamber of the
probe via the two liquid connectors. In some embodiments, the spark
module includes a first liquid connector configured to fluidly
communicate with the chamber when the spark module is coupled to
the probe and the probe includes a second liquid connector
configured to fluidly communicate with the chamber when the spark
module is coupled to the probe.
[0029] In some embodiments of the present apparatuses comprising a
spark module, the one or more spark gaps comprise a plurality of
spark gaps. In some embodiments, the plurality of electrodes
comprises three or four electrodes defining two spark gaps. In some
embodiments, the three or four electrodes comprises a first
peripheral electrode, a second peripheral electrode spaced apart
from the first electrode, and one or two central electrodes
configured to move back and forth between the peripheral
electrodes. In some embodiments, the spark module further
comprises: an elongated member coupled to the one or two central
electrodes and configured to move to carry the one or two central
electrodes back and forth between the peripheral electrodes. In
some embodiments, the one or two central electrodes comprise two
central electrodes in electrical communication with each other and
disposed on opposing sides of the elongated member. In some
embodiments, the elongated member is configured to self-adjust the
spark gap between the peripheral electrodes and the one or two
central electrodes within an expected range of operating
frequencies. In some embodiments, the expected range of operating
frequencies is between 10 Hz and 5 MHz. In some embodiments, the
elongated member is pivotally coupled to the sidewall and biased
toward an initial position by one or more spring arms. In some
embodiments, the elongated member and the one or more spring arms
are configured to determine a pulse rate of the spark module within
an expected range of operating frequencies. In some embodiments,
the expected range of operating frequencies is between 10 Hz and 5
MHz. In some embodiments, the apparatus is configured to discharge
electrical pulses between the electrodes while the electrodes are
submerged in a liquid such that movement of the elongated member
automatically and alternatingly adjusts the spark gap between the
one or two central electrodes and each of the peripheral
electrodes. In some embodiments, the elongated member comprises a
resilient beam having a base that is coupled in fixed relation to
the sidewall. In some embodiments, the resilient beam is configured
to determine a pulse rate of the spark module at expected operating
conditions. In some embodiments, the apparatus is configured to
discharge electrical pulses between the electrodes while the
electrodes are submerged in a liquid such that movement of the
resilient beam automatically and alternatingly adjusts the spark
gap between the one or two central electrodes and each of the
peripheral electrodes.
[0030] In some embodiments of the present apparatuses comprising a
spark module, the sidewall of the spark module comprises at least
one of pins, grooves, or threads, and is configured to be coupled
to a probe that comprises at least one of corresponding grooves,
pins, or threads to releasably couple the spark module to the
housing. Some embodiments further comprise: a probe configured to
be coupled to the spark module such that the plurality of
electrodes is disposed in a chamber that is fillable with a liquid,
and such that shockwaves originating at the electrodes will travel
through a shockwave outlet of the apparatus. In some embodiments,
the chamber is filled with liquid. In some embodiments, the probe
does not define an additional chamber, such that the spark chamber
is the only chamber through which shockwaves originating at the
electrodes will propagate. In some embodiments, the probe defines a
second chamber within which the spark chamber is disposed if the
spark module is coupled to the probe. In some embodiments, the
probe includes a plurality of electrical connectors configured to
be coupled to the plurality of electrical connectors of the spark
module. In some embodiments, the probe includes one or more liquid
connectors configured to be coupled to the one or more liquid
connectors of the spark module. In some embodiments, the probe
includes two liquid connectors configured to be coupled to the two
liquid connectors of the spark module. In some embodiments, the
spark module is configured to be coupled to the probe such that the
electrical and liquid connectors of the spark module are
simultaneously connected to the respective electrical and liquid
connectors of the probe as the spark module is coupled to the
probe. In some embodiments, the probe includes one or more liquid
connectors configured to be coupled to the one or more liquid
connectors of the spark module. In some embodiments, the probe
includes a combined connection having two or more electrical
conductors and two lumens for communicating liquid, the combined
connection configured to be coupled to a combined tether or cable
that has two or more electrical conductors and two lumens for
communicating liquid. In some embodiments, combined connection is
configured to be removably coupled to the combined tether or
cable.
[0031] In some embodiments of the present apparatuses comprising a
spark module and a probe, the probe includes a housing with a
translucent or transparent window that is configured to permit a
user to view a region of a patient comprising target cells. In some
embodiments, if the spark module is coupled to the probe, the
plurality of electrodes is not visible to a user viewing a region
through the window and the shockwave outlet. Some embodiments
further comprise: an optical shield disposed between the window and
the plurality of electrodes. In some embodiments, the optical
shield includes a light-sensitive material that darkens or
increases in opacity in the presence of bright light. In some
embodiments, the plurality of electrodes are offset from an optical
path extending through the window and the shockwave outlet. Some
embodiments further comprise: an acoustic mirror configured to
reflect shockwaves from the plurality of electrodes to the
shockwave outlet. In some embodiments, the acoustic mirror
comprises glass.
[0032] Some embodiments of the present apparatuses comprise: a
probe configured to be coupled to a spark module having a plurality
of electrodes defining one or more spark gaps such that the
plurality of electrodes is disposed in a chamber that is fillable
with a liquid. In some embodiments, the chamber is filled with
liquid. In some embodiments, the probe is configured to cooperate
with the spark module to define the chamber. In some embodiments,
the probe includes a first liquid connector configured to fluidly
communicate with the chamber when the spark module is coupled to
the probe, and is configured to be coupled to a spark module that
includes a second liquid connector that is configured to fluidly
communicate with the chamber when the spark module is coupled to
the probe.
[0033] In some embodiments, the spark module includes a sidewall
defining a spark chamber within which the plurality of electrodes
are disposed, and the probe does not define an additional chamber,
such that the spark chamber is the only chamber through which
shockwaves originating at the electrodes will propagate. In some
embodiments, the spark module includes a sidewall defining a spark
chamber within which the plurality of electrodes are disposed,
where the probe defines a second chamber within which the spark
chamber is disposed if the spark module is coupled to the probe. In
some embodiments, the probe includes a plurality of electrical
connectors configured to be coupled to a plurality of electrical
connectors of the spark module that are in electrical communication
with the plurality of electrodes. In some embodiments, the probe
includes one or more liquid connectors configured to be coupled to
one or more liquid connectors of the spark module. In some
embodiments, the probe includes two liquid connectors configured to
be coupled to the two liquid connectors of the spark module. In
some embodiments, the spark module is configured to be coupled to
the probe such that the electrical and liquid connectors of the
spark module are simultaneously connected to the respective
electrical and liquid connectors of the probe as the spark module
is coupled to the probe.
[0034] In some embodiments of the present apparatuses comprising a
probe, the probe includes a combined connection having two or more
electrical conductors and two lumens for communicating liquid, the
combined connection configured to be coupled to a combined tether
or cable that has two or more electrical conductors and two lumens
for communicating liquid. In some embodiments, the combined
connection is configured to be removably coupled to the combined
tether or cable. In some embodiments, the probe includes a housing
with a translucent or transparent window that is configured to
permit a user to view a region of a patient comprising target
cells. In some embodiments, if the spark module is coupled to the
probe, the plurality of electrodes is not visible to a user viewing
a region through the window and the shockwave outlet. Some
embodiments further comprise: an optical shield disposed between
the window and the plurality of electrodes. In some embodiments,
the plurality of electrodes are offset from an optical path
extending through the window and the shockwave outlet. Some
embodiments further comprise: an acoustic mirror configured to
reflect shockwaves from the plurality of electrodes to the
shockwave outlet. In some embodiments, the acoustic mirror
comprises glass.
[0035] Some embodiments of the present apparatuses comprising a
probe further comprise: a pulse-generation system configured to
repeatedly store and release an electric charge, the
pulse-generation system configured to be coupled to the electrical
connectors of the spark module to release the electric charge
through the electrodes of the spark module. In some embodiments,
the pulse-generation system is configured to apply voltage pulses
to the plurality of electrodes at a rate of between 20 Hz and 200
Hz. In some embodiments, the pulse-generation system is configured
to apply voltage pulses to the plurality of electrodes at a rate of
between 50 Hz and 200 Hz. In some embodiments, the pulse-generation
system includes a single charge/discharge circuit. In some
embodiments, the pulse-generation system includes a plurality of
charge/discharge circuits and a timing unit configured to
coordinate charging and discharging of the plurality of
charge/discharge circuits. In some embodiments, each of the
charge/discharge circuits includes a capacitive/inductive coil
circuit. In some embodiments, each capacitive/inductive coil
circuit comprises: an induction coil configured to be discharged to
apply at least some of the voltage pulses; a switch; and a
capacitor; where the capacitor and the switch are coupled in
parallel between the induction coil and the timing unit. Some
embodiments further comprise: a liquid reservoir; and a pump
configured to circulate liquid from the reservoir to the chamber of
the housing.
[0036] Some embodiments of the present apparatuses comprise: a
pulse-generation system including a plurality of charge/discharge
circuits and a timing unit configured to coordinate charging and
discharging of the plurality of charge/discharge circuits at a rate
of between 10 where the pulse-generation system is configured to be
coupled to a plurality of electrodes of a spark module to discharge
the charge/discharge circuits through the electrodes. Some
embodiments further comprise: configured each of the
charge/discharge circuits includes a capacitive/inductive coil
circuit. each capacitive/inductive coil circuit comprises: an
induction coil configured to be discharged to apply at least some
of the voltage pulses; a switch; and a capacitor; where the
capacitor and the switch are coupled in parallel between the
induction coil and the timing unit. the pulse-generation system is
configured to apply voltage pulses to the plurality of electrodes
at a rate of between 20 Hz and 200 Hz. the pulse-generation system
is configured to apply voltage pulses to the plurality of
electrodes at a rate of between 50 Hz and 200 Hz. Some embodiments
further comprise: a liquid reservoir; and a pump configured to
circulate liquid from the reservoir to the chamber of the
housing.
[0037] Some embodiments of the present methods comprise:
positioning the shockwave outlet of one of the present apparatuses
adjacent to a region of a patient comprising target cells; and
activating a pulse-generation system to propagate a shockwaves
through the fluid to the target cells. In some embodiments, at
least a portion of the plurality of shock waves are delivered to a
portion of an epidermis layer of a patient that includes a tattoo.
In some embodiments, a housing and/or probe of the apparatus
includes a translucent or transparent window that is configured to
permit a user to view a region of a patient comprising target
cells; and the method further comprises: viewing the region through
the window while positioning the apparatus. In some embodiments,
the apparatus includes a spark module (that comprises: a sidewall
configured to releasably couple the spark module to the housing;
where the plurality of electrodes is coupled to the sidewall such
that the plurality of electrodes is disposed in the chamber if the
spark module is coupled to the housing), and the method further
comprises: coupling the spark module to the housing prior to
activating the pulse-generation system.
[0038] Some embodiments of the present methods comprise:
electro-hydraulically generating a plurality of shock waves at a
frequency of between 10; delivering at least a portion of the
plurality of shock waves to at least one cellular structure
comprising at least one region of heterogeneity; and rupturing the
at least one cellular structure with the continued delivery of the
plurality of shock waves. In some embodiments, the at least one
region of heterogeneity comprises an effective density greater than
an effective density of the at least one cellular structure. Some
embodiments further comprise the step of varying the frequency of
the acoustic waves. In some embodiments, at least a portion of the
plurality of shock waves are delivered to an epidermis layer of a
patient. In some embodiments, a portion of the epidermis layer
receiving the shock waves includes cells that contain tattoo
pigment particles. Some embodiments further comprise: identifying
at least one target cellular structure be ruptured prior to
delivering at least a portion of shock waves to the at least one
target cellular structure.
[0039] Some embodiments of the present methods comprise: delivering
a plurality of electro-hydraulically generated shock waves to at
least one cellular structure comprising at least one region of
heterogeneity until the at least one cellular structure ruptures.
In some embodiments, at least a portion of the plurality of shock
waves are delivered to a portion of an epidermis layer of a patient
that includes cells that contain tattoo pigment particles. In some
embodiments, the shock waves are delivered to the at least one
cellular structure for no more than 30 minutes in a 24-hour period.
In some embodiments, the shock waves are delivered to the at least
one cellular structure for no more than 20 minutes in a 24-hour
period. In some embodiments, between 200 and 5000 shockwaves are
delivered in between 30 seconds and 20 minutes at each of a
plurality of positions of a shockwave outlet. Some embodiments
further comprise: tensioning a portion of a patient's skin while
delivering the shockwaves. In some embodiments, the tensioning is
performed by pressing a convex outlet member against the portion of
the patient's skin. Some embodiments further comprise: delivering
laser light to the at least one cellular structure; and/or
delivering a chemical or biological agent to the at least one
cellular.
[0040] Any embodiment of any of the present systems, apparatuses,
and methods can consist of or consist essentially of--rather than
comprise/include/contain/have--any of the described steps,
elements, and/or features. Thus, in any of the claims, the term
"consisting of" or "consisting essentially of" can be substituted
for any of the open-ended linking verbs recited above, in order to
change the scope of a given claim from what it would otherwise be
using the open-ended linking verb.
[0041] Details associated with the embodiments described above and
others are presented below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0042] The following drawings illustrate by way of example and not
limitation. For the sake of brevity and clarity, every feature of a
given structure is not always labeled in every figure in which that
structure appears. Identical reference numbers do not necessarily
indicate an identical structure. Rather, the same reference number
may be used to indicate a similar feature or a feature with similar
functionality, as may non-identical reference numbers. The figures
are drawn to scale (unless otherwise noted), meaning the sizes of
the depicted elements are accurate relative to each other for at
least the embodiment depicted in the figures.
[0043] FIG. 1 depicts a block diagram of a first embodiment of the
present electro-hydraulic (EH) shockwave generating systems.
[0044] FIG. 2 depicts a cross-sectional side view of a handheld
probe for some embodiments of the present EH shockwave generating
systems.
[0045] FIG. 2A depicts a cross-sectional side view of a first
embodiment of a removable spark head usable with embodiments of the
present handheld probes, such as the one of FIG. 2.
[0046] FIG. 2B depicts a cutaway side view of a second embodiment
of a removable spark head usable with embodiments of the present
handheld probes, such as the one of FIG. 2.
[0047] FIG. 2C depicts a cutaway side view of a third embodiment of
a removable spark head usable with embodiments of the present
handheld probes, such as the one of FIG. 2.
[0048] FIG. 3A-3B depict a timing diagrams of one example of the
timed application of energy cycles or voltage pulses in the system
of FIG. 1 and/or the handheld probe of FIG. 2.
[0049] FIG. 4 depicts a waveform that can be emitted by system of
FIG. 1 and/or the handheld probe of FIG. 2 into target tissue.
[0050] FIG. 5 depicts a schematic diagram of one embodiment of a
multi-gap pulse-generation system for use in or with some
embodiments of the present systems.
[0051] FIG. 6 depicts a block diagram of an embodiment of a
radio-frequency (RF) powered acoustic ablation system.
[0052] FIGS. 7A-7B depict perspective and cross-sectional views of
a first prototyped spark chamber housing.
[0053] FIG. 8 depicts a cross-sectional view of a second prototyped
embodiment of spark chamber housing.
[0054] FIG. 9 depicts a schematic diagram of an electric circuit
for a prototyped pulse-generation system.
[0055] FIG. 10 depicts a conceptual flowchart of one embodiment of
the present methods.
[0056] FIG. 11 depicts an exploded perspective view of a further
prototyped embodiment of the present probes having a spark head or
module.
[0057] FIGS. 12A and 12B depict parts of the assembly of the probe
of FIG. 11.
[0058] FIGS. 13A and 13B depict perspective and side
cross-sectional views, respectively, of the probe of FIG. 11.
[0059] FIG. 13C depicts an enlarged side cross-sectional view of a
spark gap of the probe of FIG. 11.
[0060] FIG. 14 depicts a schematic diagram of a second embodiment
of an electric circuit for a prototyped pulse-generation
system.
DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0061] The term "coupled" is defined as connected, although not
necessarily directly, and not necessarily mechanically; two items
that are "coupled" may be unitary with each other. The terms "a"
and "an" are defined as one or more unless this disclosure
explicitly requires otherwise. The term "substantially" is defined
as largely but not necessarily wholly what is specified (and
includes what is specified; e.g., substantially 90 degrees includes
90 degrees and substantially parallel includes parallel), as
understood by a person of ordinary skill in the art. In any
disclosed embodiment, the terms "substantially," "approximately,"
and "about" may be substituted with "within [a percentage] of" what
is specified, where the percentage includes 0.1, 1, 5, and 10
percent.
[0062] The terms "comprise" (and any form of comprise, such as
"comprises" and "comprising"), "have" (and any form of have, such
as "has" and "having"), "include" (and any form of include, such as
"includes" and "including") and "contain" (and any form of contain,
such as "contains" and "containing") are open-ended linking verbs.
As a result, a system or apparatus that "comprises," "has,"
"includes" or "contains" one or more elements possesses those one
or more elements, but is not limited to possessing only those
elements. Likewise, a method that "comprises," "has," "includes" or
"contains" one or more steps possesses those one or more steps, but
is not limited to possessing only those one or more steps.
[0063] Further, a structure (e.g., a component of an apparatus)
that is configured in a certain way is configured in at least that
way, but it can also be configured in other ways than those
specifically described.
[0064] Certain embodiments of the present systems and apparatuses
are configured to generate high-frequency shock waves in a
predictable and consistent manner. In some embodiments, the
generated EH shock waves can be used in medical and/or aesthetic
therapeutic applications (e.g., when directed at and/or delivered
to target tissue of a patient). Examples of medical and/or
aesthetic therapeutic applications in which the present systems can
be used are disclosed in: (1) U.S. patent application Ser. No.
13/574,228, published as US 2013/0046207; and (2) U.S. patent
application Ser. No. 13/547,995, published as, published as US
2013/0018287; both of which are incorporated here in their
entireties. The EH shock waves generated by the present systems can
be configured to impose sufficient mechanical stress to rupture in
cells of the target tissue (e.g., through membrane-degradation
damage).
[0065] When targeted cells (cells of target tissue) are exposed to
the generated high-PR shockwaves, the cells experience sharp
gradients of mechanical stress due to the spatial heterogeneity
parameters of the cells, such as density and shear elasticity
modulus of the different components of the cell. For instance,
dense and/or inelastic components inside a cell undergo greater
mechanical stress when subjected to shock waves as compared to
lighter components. In particular, acceleration of higher-density
particles or components within the cellular structure exposed to
the impact front is typically very large. At the same time, the
impact on lower-density biological structures making up the cell
structure when exposed to such a large gradient of pressure is
significantly reduced because the elasticity of the lower-density
biological structures allows them to generally act as
low-compliance material. The difference in mechanical stress
results in movement of the dense and/or inelastic components within
the cell.
[0066] When the cell is exposed to repeated shock waves at a
certain frequency and energy level, the dense and/or inelastic
components are repeatedly moved until they break out of the cell,
thereby rupturing the cell. In particular, the properties mismatch
of the cellular structure and cells' ability to experience
deformation when exposed to the impact front lead to cellular
destruction as described. One possible theory to explain the
phenomenon of rupturing cellular structure can be found in (Burov,
V. A., 2002) [1], which is incorporated herein by reference in its
entirety.
[0067] As discussed by Burov [1], while a cell may oscillate as an
integral unit when impacted by these pressure fronts, sharp
gradients of mechanical stress can be generated inside the cell as
a result of spatial heterogeneity parameters (i.e., density and
shear elasticity modulus). This concept can be illustrated by
modeling the biological structure as two linked balls with masses
m.sub.1 and m.sub.2 and the density (.rho..sub.0) of the liquid
oscillating around the balls with the speed .mu..sub.o(t) differ
insignificantly from the densities of the balls (by .rho..sub.1 and
.rho..sub.2 respectively). If only the resistance to potential flow
is taken into account, the force applied to the link is calculated
as shown in Equation (1):
F = 2 3 m 1 m 2 m 1 + m 2 [ .rho. 1 - .rho. 2 ] .rho. 0 .mu. 0 ( t
) ( 1 ) ##EQU00001##
[0068] Additional discussions of Equation (1) and its variables are
further provided in [1]. For example, if the ball radius (R) is
about 10 .mu.m and the difference between the densities of the
balls is 0.1 .rho..sub.0, and results in a stress force,
F/(.pi.R.sup.2)m of 10.sup.9 dyne/cm.sup.2. This is sufficient to
rupture a cell membrane. The embodiments of the present apparatuses
generate shock waves in a controlled manner that can be used to
cause targeted damage to certain cells, which have medical and/or
aesthetic therapeutic applications that are discussed further
below.
[0069] Another possible theory to explain the phenomenon of cell
rupturing is the accumulation shear stress in the denser material
in the cellular structure. In heterogeneous media, such as cells
with particles (e.g., pigment particles), shock waves cause the
cell membranes to fail by a progressive (i.e., accumulated)
shearing mechanism. On the other hand, in homogeneous media,
compression by shock waves causes minimal, if any, damage to
membranes. Microscopic focusing and defocusing of the shock wave as
it passes through the heterogeneous media can result in shock wave
strengthening or weakening locally that result in an increase in
local shearing. Relative shearing motion of the cell membrane
occurs on the scale of the heterogeneities of the cellular
structure. It is believed that when shock waves strike a region of
heterogeneities (e.g., cells containing particles), the particle
motion that is out of phase with the incoming waves generates cell
disruptive energy transfer (e.g., shear stress). The out of phase
motion (e.g., shear stress) causes microscopic damage to the cell
membrane that can progressively grow into cell membrane failure
with additional successive accumulation of shear stress.
[0070] The progressive shearing mechanism of repeated exposure to
shock waves can be considered dynamic fatigue of the cell
membranes. Damage from dynamic fatigue is dependent on three
factors: (1) applied stress or strain, (2) the rate at which the
strain is applied, and (3) accumulated number of strain cycles.
These three factors can be manipulated to cause a cell with
heterogeneities to experience catastrophic cell membrane failure as
compared to a relatively more homogeneities at a particular applied
strain, strain rate, and strain cycles.
[0071] The manipulation of the factors can be done by providing EH
shock waves of certain properties, such as the number of shock
waves, the amount of time between each shock wave, and the strength
of the applied shock waves. As discussed above, if there is too
much time between shock waves for the tissue to relax to its
unstrained state, the cells will become more resistant to failure.
As such, in the preferred embodiment for an EH system, shock waves
at a PR greater than 5 Hz and preferably greater than 100 Hz and
most preferably greater than 1 MHz are delivered to the targeted
cellular structures to achieve dynamic fatigue of the tissue and
not allow the tissue time to relax.
[0072] At high enough PR, tissues behave as a viscous material. As
a result, the PR and power level can be adjusted to account for the
tissue's viscous properties.
[0073] A third possible theory is that the EH shock waves cause a
combination of effects of direct movement of the particles
contained in the cellular structure and dynamic fatigue that
rupture the cells. While particle-containing cells are an apparent
example of cellular structures exhibiting heterogeneities, their
description is not intended to limit the scope of the present
disclosure. Instead, the embodiments disclosed herein can be used
to rupture or cause damage to other cellular structures that
exhibit heterogeneities, such as cellular structures that have
different effective density regions. The parameters of the shock
waves generated according to the disclosed aspects can be adjusted
based, at least, on the regions of different effective densities
(i.e. heterogeneities) to cause cellular damage as described
herein. Heterogeneities can be regions within a single cell, a
region of different types of cells, or a combination of both. In
certain embodiments, a region of heterogeneity within a cell
includes a region having an effective density greater than the
effective density of the cell. In one specific example, the
effective density of a fibroblast cell is about 1.09 g/cm.sup.3, a
region of heterogeneity in the cell would be particles contained
within the cell that have an effective density greater than 1.09
g/cm.sup.2, such as graphite with a density of 2.25 g/cm.sup.3. In
certain embodiments, a region of cellular heterogeneity between
cells includes a region with different types of cells, where each
cell type has a different effective density, such as fibroblast
cells and fat cells or hair follicles. The present disclosure
provides further examples of cellular structures containing
heterogeneities below.
[0074] Referring now to the drawings, and more particularly to FIG.
1, shown therein and designated by the reference numeral 10 is a
block diagram of one embodiment of the present apparatuses or
systems for electro-hydraulically generating shockwaves in a
controlled manner. In some embodiments, such as the one shown,
system 10 includes a handheld probe (e.g., with a first housing,
such as in FIG. 2) and a separate controller or pulse-generation
system (e.g., in or with a second housing coupled to the handheld
probe via a flexible cable or the like). In other embodiments, the
present systems include a single handheld apparatus disposed in a
single housing.
[0075] In the embodiment shown, apparatus 10 comprises: a housing
14 defining a chamber 18 and a shockwave outlet 20; a liquid (54)
disposed in chamber 18; a plurality of electrodes (e.g., in spark
head or module 22) configured to be disposed in the chamber to
define one or more spark gaps; and a pulse-generation system 26
configured to apply voltage pulses to the electrodes at a rate of
between 10 Hz and 5 MHz. In this embodiment, the
capacitive/inductive coil system 26 is configured to apply the
voltage pulses to the electrodes such that portions of the liquid
are vaporized to propagate shockwaves through the liquid and the
shockwave outlet.
[0076] In the embodiment shown, pulse-generation system 26 is
configured for use with an alternating current power source (e.g.,
a wall plug). For example, in this embodiment, pulse-generation
system 26 comprises a plug 30 configured to be inserted into a 110V
wall plug. In the embodiment shown, pulse-generation system 26
comprises a capacitive/inductive coil system, on example of which
is described below with reference to FIG. 6. In other embodiment,
pulse-generation system 26 can comprise any suitable structure or
components configured to apply high voltages to the electrodes in a
periodic fashion to generate electric sparks of sufficient power to
vaporize liquid in the respective spark gaps, as described in this
disclosure.
[0077] In the embodiment shown, pulse-generation system 26 is
(e.g., removably) coupled to the electrodes in spark head or module
22 via a high-voltage cable 34, which may, for example, include two
or more electrical conductors and/or be heavily shielded with
rubber or other type of electrically insulating material to prevent
shock. In some embodiments, high-voltage cable 34 is a combined
tether or cable that further includes one or more (e.g., two)
liquid lumens through which chamber 18 can be filled with liquid
and/or via which liquid can be circulated through chamber 18 (e.g.,
via combined connection 36). In the embodiment shown, apparatus 10
comprises a handheld probe or handpiece 38 and cable 34 is
removably coupled to probe 38 via a high-voltage connector 42,
which is coupled to spark head or module 22 via two or more
electrical conductors 44. In the embodiment shown, probe 38
comprises a head 46 and a handle 50, and probe 38 can comprise a
polymer or other electrically insulating material to enable an
operator to grasp handle 50 to position probe 38 during operation.
For example, handle 50 can be molded with plastic and/or can be
coated with an electrically insulating material such as rubber.
[0078] In the embodiment shown, a liquid 54 (e.g., a dielectric
liquid such as distilled water) is disposed in (e.g., and
substantially fills) chamber 18. In this embodiment, spark head 22
is positioned in chamber 18 and surrounded by the liquid such that
the electrodes can receive voltage pulses from pulse-generation
system 26 (e.g., at a rate of between 10 Hz and 5 MHz) such that
portions of the liquid are vaporized to propagate shockwaves
through the liquid and shockwave outlet 20. In the embodiment
shown, probe 38 includes an acoustic delay chamber 58 between
chamber 18 and outlet 20. In this embodiment, acoustic delay
chamber is substantially filled with a liquid 62 (e.g., of the same
type as liquid 54) and has a length 66 that is sufficient to permit
shockwaves to form and/or be directed toward outlet 20. In some
embodiments, length 66 may be between 2 millimeters (mm) and 25
millimeters (mm). In the embodiment shown, chamber 18 and
acoustic-delay chamber 58 are separated by a layer of sonolucent
(acoustically permeable or transmissive) material that permits
sound waves and/or shockwaves to travel from chamber 18 into
acoustic-delay chamber 58. In other embodiments, liquid 62 may be
different than liquid 54 (e.g., liquid 62 may comprise bubbles,
water, oil, mineral oil, and/or the like). Certain features such as
bubbles may introduce and/or improve a nonlinearity in the acoustic
behavior of liquid 54 to increase the formation of shockwaves. In
further embodiments, chamber 18 and acoustic-delay chamber 54 may
be unitary (i.e., may comprise a single chamber). In further
embodiments, acoustic-delay chamber 54 may be replaced with a solid
member (e.g., a solid cylinder of elastomeric material such as
polyurethane). In the embodiment shown, probe 38 further includes
an outlet member 70 removably coupled to the housing at a distal
end of the acoustic delay chamber, as shown. Member 70 is
configured to contact tissue 74, and can be removed and either
sterilized or replaced between patients. Member 70 comprises a
polymer or other material (e.g., low-density polyethylene or
silicone rubber) that is acoustically permeable to permit
shockwaves to exit acoustic-delay chamber 58 via outlet 20. Tissue
74 may, for example, be human skin tissue to be treated with
apparatus 10, and may, for example, include a tattoo, a blemish, a
subdermal lesion, or a basal cell abnormality. In some embodiments,
an acoustic coupling gel (not shown) may be disposed between member
70 and tissue 74 to lubricate and provide additional acoustic
transmission into tissue 74.
[0079] In the embodiment shown, probe 38 includes an acoustic
mirror 78 that comprises a material (e.g., glass) and is configured
to reflect a majority of sound waves and/or shock waves that are
incident on the acoustic mirror. As shown, acoustic mirror 58 can
be angled to reflect sound waves and/or shockwaves (e.g., that
originate at spark head 22) toward outlet 20 (via acoustic-delay
chamber). In the embodiment shown, housing 14 can comprise a
translucent or transparent window 82 that is configured to permit a
user to view (through window 82, chamber 18, chamber 58, and member
70) a region of a patient (e.g., tissue 74) comprising target cells
(e.g., during application of shockwaves or prior to application of
shockwaves to position outlet 20 at the target tissue). In the
embodiment shown, window 82 comprises an acoustically reflective
material (e.g., glass) that is configured to reflect a majority of
sound waves and/or shock waves that are incident on the window. For
example, window 82 can comprise clear glass of sufficient thickness
and strength to withstand the high-energy acoustic pulses produced
at spark head 22 (e.g., tempered plate glass having a thickness of
about 2 mm and an optical transmission efficiency of greater than
50%).
[0080] In FIG. 1, a human eye 86 indicates a user viewing the
target tissue through window 82, but it should be understood that
target tissue may be "viewed" through window 82 via a camera (e.g.,
a digital still and/or video camera). By direct or indirect
observation, acoustic energy can be positioned, applied, and
repositioned according to target tissues, such as extant tattoos,
and by indications of acoustic energy, such as a change in the
color of the tissue. However, if spark head 22 is disposed where a
user can view spark head 22, the brightness of the resulting spark
from spark head 22 may be too bright for a user to comfortably
view, and in the embodiment shown, probe 38 is configured such that
the plurality of electrodes are not visible to a user viewing a
region (e.g., of target tissue) through window 82 and outlet 20.
For example, in the embodiment shown, probe 38 includes an optical
shield 90 disposed between spark head 22 and window 82. Shield 90,
for example, can have a width and/or a length that are less than a
corresponding width and/or length of window 82 such that shield 90
is large enough to substantially block light from spark head 22
from traveling directly to the user's eye, but does not interfere
with the field-of-view through window 82 and outlet 20 more than is
necessary to block that light. Shield 90 can, for example, comprise
a thin sheet of metal, such as stainless steel, or other opaque
material, or can comprise welder's glass (e.g., an LCD darkened by
a photocell or other light-sensitive material) that is optically
activated and darkened by the brightness of sparks at the spark
gaps. The acoustic effect of shielding the resulting sparks from a
spark gap head must be considered in order to maintain the effect
of a point source from spark head 22 and a resulting desired planar
wavefront. If shield 90 comprises an acoustically reflective
material, to prevent pulse broadening, the distance between the
shield and the spark gaps between electrodes in spark head 22 may
be selected to minimize (e.g., at least destructive) interference
between sound waves and/or shockwaves reflected from the shield and
sound waves and/or shockwaves originating at spark head 22 (e.g.,
such that intersecting waves do not produce excess echoes or
reverberation). With a velocity of sound waves in a medium such as
distilled water of about 1500 m/Sec, the distance between the spark
head and the shield may be calculated to be at 1/2 and 3/4
wavelengths from the source.
[0081] Spark head 22 (e.g., the electrodes in spark head 22) may
have a limited lifetime that may be extended by limiting the
duration of activation. In the embodiment shown, apparatus 10
includes a switch or trigger 94 coupled to pulse-generation system
26 via a switch wire or other connection 98 through connector 42,
such that switch 94 can be actuated to apply voltage pulses to the
electrodes in spark head 22.
[0082] FIG. 2 depicts a cross-sectional side view of a second
embodiment 38a of the present handheld probes or handpiece for use
with some embodiments of the present EH shockwave generating
systems and apparatuses. Probe 38a is substantially similar in some
respects to probe 38, and the differences are therefore primarily
described here. For example, probe 38a is also configured such that
the plurality of electrodes of spark head or module 22a are not
visible to a user viewing a region (e.g., of target tissue) through
window 82a and outlet 20a. However, rather than including an
optical shield, probe 38a is configured such that spark head 22a
(and the electrodes of the spark head) are offset from an optical
path extending through window 82a and outlet 20a. In this
embodiment, acoustic mirror 78a is positioned between spark head
22a and outlet 20a, as shown, to define a boundary of chamber 18a
and to direct acoustic waves and/or shockwaves from spark head 22a
to outlet 20a. In the embodiment shown, window 82a can comprise a
polymer or other acoustically permeable or transmissive material
because acoustic mirror 78a is disposed between window 82a and
chamber 18a and sound waves and/or shockwaves are not directly
incident on window 82a (i.e., because the sound waves and/or shock
waves are primarily reflected by acoustic mirror 78a).
[0083] In the embodiment shown, spark head 22a includes a plurality
of electrodes 100 that define a plurality of spark gaps. The use of
multiple spark gaps can be advantageous because it can double the
number of pulses that can be delivered in a given period of time.
For example, after a pulse vaporizes an amount of liquid in a spark
gap the vapor must either return to its liquid state or must be
displaced by a different portion of the liquid that is still in a
liquid state. In addition to the time required for the spark gap to
be re-filled with water before a subsequent pulse can vaporize
additional liquid, sparks also heat the electrodes. As such, for a
given spark rate, increasing the number of spark gaps reduces the
rate at which each spark gap must be fired and thereby extends the
life of the electrodes. Thus, ten spark gaps potentially increases
the possible pulse rate and/or electrode life by a factor of
ten.
[0084] As noted above, high pulse rates can generate large amounts
of heat that may increase fatigue on the electrodes and/or increase
the time necessary for vapor to return to the liquid state after it
is vaporized. In some embodiments, this heat can be managed by
circulating liquid around the spark head. For example, in the
embodiment of FIG. 2, probe 38 includes conduits 104 and 108
extending from chamber 18a to respective connectors 112 and 116, as
shown. In this embodiment, connectors 112 and 116 can be coupled to
a pump to circulate liquid through chamber 18a (e.g., and through a
heat exchanger. For example, in some embodiments, pulse-generation
system 26 (FIG. 1) can comprise a pump and a heat exchanger in
series and configured to be coupled to connectors 112 and 116 via
conduits or the like. In some embodiments, a filter can be included
in probe 38a, in a spark generation system (e.g., 26), and/or
between the probe and the spark generation system to filter liquid
that is circulated through the chamber
[0085] Additionally, due to the limited life of electrodes 100 at
high pulse rates, some embodiments of the present probes may be
disposable. Alternatively, some embodiments are configured to
permit a user to replace the electrodes. For example, in the
embodiment of FIG. 2, spark head 22a is configured to be removable
from probe 38a. For example, spark head 22a may be removable
through handle 50a, or handle 50a may be removably coupled (e.g.,
via threads or the like) to head 46a such that upon removal of
handle 50a from head 46, spark head 22a can be removed from head
46a and replaced.
[0086] As illustrated in FIG. 2, application of each shockwave to a
target tissue includes a wavefront 118 propagating from outlet 20a
and traveling outward through tissue 74. As shown, wavefront 74 is
curved according to its expansion as it moves outwardly and
partially according to the shape of the outer surface of outlet
member 70a that contacts tissue 74. In other embodiments, such as
that of FIG. 1, the outer shape of the contact member can be planar
or otherwise shaped to affect certain properties of the wavefront
as it passes through outlet 20a and propagates through the target
tissue.
[0087] FIG. 2A depicts an enlarged cross-sectional view of first
embodiment of a removable spark head or module 22a. In the
embodiment shown, spark head 22a comprises a sidewall 120 defining
a spark chamber 124, and a plurality of electrodes 100a, 100b, 100c
disposed in the spark chamber. In the embodiment shown, spark
chamber 124 is filled with liquid 128 which may be similar to
liquid 54 (FIG. 1). At least a portion of sidewall 120 comprises an
acoustically permeable or transmissive material (e.g., a polymer
such as polyethylene) configured to permit sound waves and/or
shockwaves generated at the electrodes to travel through sidewall
120 and through chamber 18a. For example, in the embodiment shown,
spark head 22a includes a cup-shaped member 132 that may be
configured to be acoustically reflective and an acoustically
permeable cap member 136. In this embodiment, cap member 136 is
dome shaped to approximate the curved shape of an expanding
wavefront that originates at the electrodes and to compress the
skin when applied with moderate pressure. Cap member 136 can be
coupled to cup-shaped member 132 with an O-ring or gasket 140 and a
retaining collar 144. In the embodiment shown, cup-shaped member
132 has a cylindrical shape with a circular cross-section (e.g.,
with a diameter of 2 inches or less). In this embodiment,
cup-shaped member includes bayonet-style pins 148, 152 configured
to align with corresponding grooves in head 46a of probe 38a (FIG.
2) to lock the position of spark head 22a relative to the
probe.
[0088] In the embodiment shown, an electrode core 156 having
conductors 160a, 160b, 160c and extending through aperture 164,
with the interface between aperture 164 and electrode core 156
sealed with a grommet 168. In the embodiment shown, a central
conductor 160a extends through the center of core 156 and serves as
a ground to corresponding center electrode 100a. Peripheral
conductors 160b, 160c are in communication with peripheral
electrodes 100b, 100c to generate sparks across the spark gap
between electrodes 100a and 100b, and between electrodes 100a and
100c. It should be understood that while two spark gaps are shown,
any number of spark gaps may be used, and may be limited only by
the spacing and size of the spark gaps. For example, other
embodiments include 3, 4, 5, 6, 7, 8, 9, 10, or even more spark
gaps.
[0089] FIG. 2B depicts an enlarged cutaway side view of a second
embodiment of a removable spark head or module 22b. In the
embodiment shown, spark head or module 22b comprises a sidewall
120a defining a spark chamber 124a, and a plurality of electrodes
100d-1, 100d-2, 100, 100f disposed in the spark chamber. In the
embodiment shown, spark chamber 124a is filled with liquid 128a
which may be similar to liquid 128 and/or 54. At least a portion of
sidewall 120a comprises an acoustically permeable or transmissive
material (e.g., a polymer such as polyethylene) configured to
permit sound waves and/or shockwaves generated at the electrodes to
travel through sidewall 120a and through chamber 18a (FIG. 2). For
example, in the embodiment shown, spark head 22b includes a
cup-shaped member 132a that may be configured to be acoustically
reflective and an acoustically permeable cap member 136a. In this
embodiment, cap member 136a is dome shaped to approximate the
curved shape of an expanding wavefront that originates at the
electrodes and to compress the skin when applied with moderate
pressure. Cap member 136a can be coupled to cup-shaped member 132a
with an O-ring or gasket (not shown, but similar to 140) and a
retaining collar 144a. In the embodiment shown, cup-shaped member
132a has a cylindrical shape with a circular cross-section (e.g.,
with a diameter of 2 inches or less. In some embodiments,
cup-shaped member can also include bayonet-style pins (not shown,
but similar to 148, 152) configured to align with corresponding
grooves in head 46a of probe 38a to lock the position of spark head
22b relative to the probe.
[0090] In the embodiment shown, conductors 160d, 160e, 160f
extending through a rear portion (opposite outlet cap member 136a)
of sidewall 132a, as shown. In this embodiment, central conductor
160b and peripheral conductors 160a, 160c can be molded into
sidewall 120a such that grommets and the like are not necessary to
seal the interface between the sidewall and the conductors. In the
embodiment shown, a central conductor 160d serves as a ground to
corresponding center electrodes 100d-1 and 100d-2, which are also
in electrical communication with each other. Peripheral conductors
160e, 160f are in communication with peripheral electrodes 100e,
100f to generate sparks across the spark gap between electrodes
100d-1 and 100e, and between electrodes 100d-2 and 100f. It should
be understood that while two spark gaps are shown, any number of
spark gaps may be used, and may be limited only by the spacing and
size of the spark gaps. For example, other embodiments include 3,
4, 5, 6, 7, 8, 9, 10, or even more spark gaps.
[0091] In the embodiment shown, central electrodes 100d-1 and
100d-2 are carried by, and may be unitary with, an elongated member
172 extending into chamber 124a toward cap member 136a from
sidewall 120a. In this embodiment, member 172 is mounted to a hinge
176 (which is fixed relative to sidewall 120a) to permit the distal
end of the member (adjacent electrodes 100d-1, 100d-2 to pivot back
and forth between electrodes 100e and 100f, as indicated by arrows
180. In the embodiment shown, the distal portion of member 172 is
biased toward electrode 100e by spring arms 184. In this
embodiment, spring arms 184 are configured to position electrode
100d-1 at an initial spark gap distance from electrode 100e. Upon
application of an electrical potential (e.g., via a
pulse-generation system, as described elsewhere in this disclosure)
across electrodes 100d-1 and 100e, a spark will arc between these
two electrodes to release an electric pulse to vaporize liquid
between these two electrodes. The expansion of vapor between these
two electrodes drives member 172 and electrode 100d-2 downward
toward electrode 100f. During the period of time in which member
172 travels downward, the pulse-generation system can re-charge and
apply an electric potential between electrodes 100d-2 and 100f,
such that when the distance between electrodes 100d-2 and 100f
becomes small enough, a spark will arc between these two electrodes
to release the electric pulse to vaporize liquid between these two
electrodes. The expansion of vapor between electrodes 100d-2 and
100f then drives member 172 and electrode 100d-1 upward toward
electrode 100e. During the period of time in which member 172
travels upward, the pulse-generation system can re-charge and apply
an electric potential between electrodes 100d-1 and 100e, such that
when the distance between electrodes 100d-1 and 100e becomes small
enough, a spark will arc between these two electrodes to release
the electric pulse and vaporize liquid between these two
electrodes, causing the cycle to begin again. In this way, member
172 oscillates between electrodes 100e and 100f until the electric
potential ceases to be applied to the electrodes.
[0092] The exposure to high-rate and high-energy electric pulses,
especially in liquid, subjects the electrodes to rapid oxidation,
erosion, and/or other deterioration that can vary the spark gap
distance between electrodes if the electrodes are held in fixed
positions (e.g., requiring electrodes to be replaced and/or
adjusted). However, in the embodiment of FIG. 2B, the pivoting of
member 172 and electrodes 100d-1, 100d-2 between electrodes 100e
and 100f effectively adjusts the spark gap for each spark. In
particular, the distance between electrodes at which current arcs
between the electrodes is a function of electrode material and
electric potential. As such, once the nearest surfaces (even if
eroded) of adjacent electrodes (e.g., 100d-1 and 100e) reach a
spark gap distance for a given embodiment, a spark is generated
between the electrodes. As such, member 172 is configured to
self-adjust the respective spark gaps between electrodes 100d-1 and
100e, and between electrodes 100d-2 and 100f.
[0093] Another example of an advantage of the present movable
electrodes, as in FIG. 2B, is that multiple coils are not required
as long as the electrodes are positioned such that only one pair of
electrodes is within arcing distance at any given time, and such a
single coil or coil system is configured to recharge in less time
than it takes for member 172 to pivot from one electrode to the
next. For example, in the embodiment of FIG. 2B, an electric
potential may simultaneously be applied to electrodes 100e and 100f
with electrodes 100d-1 and 100d-2 serving as a common ground, with
the electric potential such that a spark will only arc between
electrodes 100d-1 and 100e when member 172 is pivoted upward
relative to horizontal (in the orientation shown), and will only
arc between electrodes 100d-2 and 100f when member 172 is pivoted
downward relative to horizontal. As such, as member 172 pivots
upward and downward as described above, a single coil or coil
system can be connected to both of peripheral electrodes 100e, 100f
and alternately discharged through each of the peripheral
electrodes. In such embodiments, the pulse rate can be adjusted by
selecting the physical properties of member 172 and spring arms
184. For example, the properties (e.g., mass, stiffness,
cross-sectional shape and area, length, and/or the like) of member
172 and the properties (e.g., spring constant, shape, length,
and/or the like) of spring arms 184 can be varied to adjust a
resonant frequency of the system, and thereby the pulse rate of the
spark head or module 22b. Similarly, the viscosity of liquid 128a
may be selected or adjusted (e.g., increased to reduce the speed of
travel of arm 172, or decreased to increase the speed of travel of
arm 172).
[0094] Another example of an advantage of the present movable
electrodes, as in FIG. 2B, is that properties (e.g., shape,
cross-sectional area, depth, and the like) of the electrodes can be
configured to achieve a known effective or useful life for the
spark head (e.g., one 30-minute treatment) such that spark head 22b
is inoperative or of limited effectiveness after that designated
useful life. Such a feature can be useful to ensure that the spark
head is disposed of after a single treatment, such as, for example,
to ensure that a new, sterile spark head is used for each patient
or area treated to minimize potential cross-contamination between
patients or areas treated.
[0095] FIG. 2C depicts an enlarged cutaway side view of a third
embodiment of a removable spark head or module 22c. Spark head 22c
is substantially similar to spark head 22b, except as noted below,
and similar reference numerals are therefore used to designate
structures of spark head 22c that are similar to corresponding
structures of spark head 22b. The primary difference relative to
spark head 22b is that spark head 22c includes a beam 172a that
does not have a hinge, such that flexing of the beam itself
provides the movement of electrodes 100d-1 and 100d-2 in the up and
down directions indicated by arrows 180, as described above for
spark head 22b. In this embodiment, the resonant frequency of spark
head 22c is especially dependent on the physical properties (e.g.,
mass, stiffness, cross-sectional shape and area, length, and/or the
like) of beam 172a. As described for spring arms 184 of spark head
22b, beam 172a is configured to be biased toward electrode 100e, as
shown, such that electrode 100d-1 is initially positioned at an
initial spark gap distance from electrode 100e. The function of
spark head 22c is similar to the function of spark head 22b, with
the exception that beam 172a itself bends and provides some
resistance to movement such that hinge 176 and spring arms 184 are
unnecessary.
[0096] In the embodiment shown, spark head 22b also includes liquid
connectors or ports 188, 192 via which liquid can be circulated
through spark chamber 124b. In the embodiment shown, a proximal end
196 of spark head 22b serves as a combined connection with two
lumens for liquid (connectors or ports 188, 192) and two or more
(e.g., three, as shown) electrical conductors (connectors 160d,
160e, 160f). In such embodiments, the combined connection of
proximal end 196 can be coupled (directly or via a probe or
handpiece) to a combined tether or cable having two liquid lumens
(corresponding to connectors or ports 188, 192), and two or more
electrical conductors (e.g., a first electrical conductor for
connecting to connector 160d and a second electrical conductor for
connecting to both peripheral connectors 160e, 160f). Such a
combined tether or cable can couple the spark head (e.g., and a
probe or handpiece to which the spark head is coupled) to a
pulse-generation system having a liquid reservoir and pump such
that the pump can circulate liquid between the reservoir and the
spark chamber. In some embodiments, cap member 136a is omitted such
that connectors or ports 188, 192 can permit liquid to be
circulated through a larger chamber (e.g., 18a) of a handpiece to
which the spark head is coupled. Likewise, a probe or handpiece to
which spark head 22a is configured to be coupled can include
electrical and liquid connectors corresponding to the respective
electrical connectors (160d, 160e, 160f) and liquid connectors
(188, 192) of the spark head such that the electrical and liquid
connectors of the spark head are simultaneously connected to the
respective electrical and liquid connectors of the probe or
handpiece as the spark module is coupled to the handpiece (e.g.,
via pressing the spark head and probe together and/or a twisting or
rotating the spark head relative probe).
[0097] In the present embodiments, a pulse rate of a few Hz to many
KHz (e.g., up to 5 MHz) may be employed. Because the fatiguing
event produced by a plurality of pulses, or shockwaves, is
generally cumulative at higher pulse rates, treatment time may be
significantly reduced by using many moderately-powered shockwaves
in rapid succession rather than a few higher powered shockwaves
spaced by long durations of rest. As noted above, at least some of
the present embodiments (e.g., those with multiple spark gaps)
enable electro-hydraulic generation of shockwaves at higher rates.
For example, FIG. 3A depicts a timing diagram enlarged to show only
two sequences of voltage pulses applied to the electrodes of the
present embodiments, and FIG. 3B depicts a timing diagram showing a
greater number of voltage pulses applied to the electrodes of the
present embodiments.
[0098] In additional embodiments that are similar to any of spark
modules 22a, 22b, 22c, a portion of the respective sidewall (120,
120a, 120b) may be omitted such that the respective spark chamber
(124, 124a, 124b) is also omitted or left open such that liquid in
a larger chamber (e.g., 18 or 18a) of a corresponding handpiece can
freely circulate between the electrodes. In such embodiments, the
spark chamber (e.g., sidewall 120, 120a, 120b can include liquid
connectors or liquid may circulate through liquid ports that are
independent of spark chamber (e.g., as depicted in FIG. 2).
[0099] The portion of pulse train or sequence 200 shown in FIG. 3A
includes pulse groups 204 and 208 timed with a delay period 212 in
between. Bursts or groups (e.g., 204, 208) may include as few as
one or two, or as many as thousands, of pulses. In general, each
group 204, 208 can include several voltage pulses that are applied
to the electrodes to trigger an event (i.e., a spark across a spark
gap). The duration of delay period 212 can be set to allow cooling
of the electrodes across each spark gap and to allow recharging of
the electronics. As used for the embodiments of this disclosure,
pulse rate refers to the rate at which voltage pulse groups (each
having one or more pulses) are applied to the electrodes; meaning
that individual pulses within pulse groups having two or more
pulses are applied at a greater frequency, as illustrated in FIGS.
3A-3B. Each of these pulse groups can be configured to generate one
shock wave or a plurality of shock waves.
[0100] A series of events (sparks) initiated by a plurality of
bursts or groups 204 and 208 delivered with the present systems and
apparatuses can comprise a higher pulse rate (PR) that can reduce
treatment time relative to lower PRs which may need to be applied
over many minutes. Tattoos, for example, may encompass broad areas
and therefore are time consuming to treat unless rapid cell
destruction is achieved (e.g., with the higher PRs of the present
disclosure). In contrast to the prior art systems noted above, the
present embodiments can be configured to deliver shock waves at a
relatively high PR 216 of 10 to 5000 or more pulses per second
(e.g., greater than any one of, or between any two of: 10 Hz, 30
Hz, 50 Hz, 1000 Hz, 10000 Hz, 1000000 Hz, 500000 Hz, and/or
5000000.
[0101] FIG. 4 depicts a waveform that can emitted by either of
probes 38 or 38a into a volume of tissue, and that is of a form
that can be useful for the elimination of tattoos. Pulse 300 is of
a typical shaped for an impulse generated by the present EH spark
heads at relatively high-voltage pulses. For example, pulse 300 has
a rapid rise time, a short duration, and a ring down period. The
units of vertical axis V.sub.a are arbitrary as may be displayed on
an oscilloscope. The actual acoustic pulse amplitude may be as low
as 50 .mu.Pa and as high as several MPa in various ones of the
present embodiments, at least because cumulative energy delivery
may be effective, as discussed above. The individual time periods
304 may be 100 nano-seconds each, which corresponds to short pulse
lengths referred to in the art as "shockwave" pulses, owing to
their sharpness and short rise and fall times. For example, a rise
time of <30 nanoseconds is considered to be a shockwave for
purposes of the present disclosure, the rapidity being particularly
effective for producing relative large pressure-temporal pressure
gradients across small, cellular-scaled structures in tissue (e.g.,
the dermis). Rapid compression and decompression of dermal
structures containing tattoo "inks" which are actually particulate
pigments, results in a fatiguing and destruction of the
pigment-containing cells over time and is believed to be one
underlying mechanism of the present methods, as described above.
For example, agitation of tissue with such shock waves has been
shown to be effective, when applied at high pulse rates within a
relatively short time period, and at sufficient energy levels to
produce a pigmented cell to rupture, with resulting liberation of
entrapped particulates and subsequent dissemination of the pigment
particles into the body, thereby reducing the appearance of the
tattoo. It is believed to be necessary to have a short pulse
waveform 300, which may be applied multiple times and preferably
many hundreds to millions of times to an area to be treated to
produce the fatigue needed for tattoo "ink" removal.
[0102] FIG. 5 depicts a schematic diagram of one embodiment 400 of
a pulse-generation system for use in or with some embodiments of
the present systems. In the embodiment shown, circuit 400 comprises
a plurality of charge storage/discharge circuits each with a
magnetic storage or induction type coil 404a, 404b, 404c (e.g.,
similar to those used in automotive ignition systems). As
illustrated, each of coils 404a, 404b, 404c, may be grounded via a
resistor 408a, 408b, 408c to limit the current permitted to flow
through each coil, similar to certain aspects of automotive
ignition systems. Resistors 408a, 408b, 408c can each comprise
dedicated resistors, or the length and properties of the coil
itself may be selected to provide a desired level of resistance.
The use of components of the type used automotive ignition systems
may reduce costs and improve safety relative to custom components.
In the embodiment shown, circuit 400 includes a spark head 22b that
is similar to spark head 22a with the exceptions that spark head
22b includes three spark gaps 412a, 412b, 412c instead of two, and
that each of the three spark gaps is defined by a separate pair of
electrodes rather than a common electrode (e.g., 100a) cooperating
with multiple peripheral electrodes. It should be understood that
the present circuits may be coupled to peripheral electrodes 100b,
100c of spark head 22a to generate sparks across the spark gaps
defined with common electrode 22a, as shown in FIG. 2A. In the
embodiment shown, each circuit is configured to function similarly.
For example, coil 404a is configured to collect and store a current
for a short duration such that, when the circuit is broken at
switch 420a, the magnetic field of the coil collapses and generates
a so-called electromotive force, or EMF, that results in a rapid
discharge of capacitor 424a across spark gap 412a.
[0103] The RL or Resistor-Inductance time constant of coil
404a--which may be affected by factors such as the size and
inductive reactance of the coil, the resistance of the coil
windings, and other factors--generally corresponds to the time it
takes to overcome the resistance of the wires of the coil and the
time to build up the magnetic field of the coil, followed by a
discharge which is controlled again by the time it takes for the
magnetic field to collapse and the energy to be released through
and overcome the resistance of the circuit. This RL time constant
generally determines the maximum charge-discharge cycle rate of the
coil. If the charge-discharge cycle is too fast, the available
current in the coil may be too low and the resulting spark impulse
weak. The use of multiple coils can overcome this limitation by
firing multiple coils in rapid succession for each pulse group
(e.g., 204, 208 as illustrated in FIG. 3A). For example, two coils
can double the practical charge-discharge rate by doubling the
(combined) current and resulting spark impulse, and three (as
shown) can effectively triple the effective charge-discharge rate.
When using multiple spark gaps, timing can be very important to
proper generation of spark impulses and resulting liquid
vaporization and shockwaves. As such, a controller (e.g.,
microcontroller, processer, FPGA, and/or the like) may be coupled
to each of control points 428a, 428b, 428c to control the timing of
the opening of switches 420a, 420b, 420c and resulting discharge of
capacitors 424a, 424b, 424c and generation of shockwaves.
[0104] FIG. 6 depicts a block diagram of an embodiment 500 of a
radio-frequency (RF) powered acoustic shockwave generation system.
In the embodiment shown, system 500 comprises a nonlinear medium
504 (e.g., as in acoustic-delay chamber 58 or nonlinear member
described above) that provides an acoustic path to from a
transducer 508 to target tissue 512 to produce practical harmonic
or acoustic energy (e.g., shockwaves). In the embodiment shown,
transducer 508 is powered and controlled through bandpass filter
and tuner 516, RF power amplifier 520, and control switch 524. The
system is configured such that actuation of switch 524 activates a
pulse generator 528 to produce timed RF pulses that drive amplifier
520 in a predetermined fashion. A typical driving waveform, for
example, may comprise a sine wave burst (e.g., multiple sine waves
in rapid succession). For example, in some embodiments, a typical
burst may have a burst length of 10 milliseconds and comprise sine
waves having a period duration of 0.1 (frequency of 100 MHz) to
more than 2 microseconds (frequency of 50 kHz).
[0105] Embodiments of the present methods comprise positioning an
embodiment of the present apparatuses (e.g., 10, 38, 38a, 500)
adjacent to a region of a patient comprising target cells (e.g.,
tissue 74); and activating the spark generation (e.g.,
capacitive/inductive coil) system (e.g., 26, 400) to propagate
shockwaves to the target cells. In some embodiments, the region is
viewed through a window (e.g., 82, 82a) while positioning the
apparatus and/or while the shockwaves are generated and delivered
to the region. Some embodiments further comprise coupling a
removable spark head or module (e.g., 22a, 22b) to a housing of the
apparatus prior to activating the pulse-generation system.
Experimental Results
[0106] Experiments were conducted on tattooed skin samples obtained
from deceased primates to observe effects of EH-generated shock
waves on tattooed skin. FIGS. 7A-7B and 8 depict two different
prototype spark chamber housings. The embodiment of FIGS. 7A-7B
depict a first embodiment 600 of a spark chamber housing that was
used in the described experiments. Housing 600 is similar in some
respects to the portion of housing 14a that defines head 46a of
probe 38a. For example, housing 600 includes fittings 604, 608 to
permit liquid to be circulated through spark chamber 612. In the
embodiment shown, housing 600 includes electrode supports 616 and
620 through which electrodes 624 can be inserted to define a spark
gap 628 (e.g., of 0.127 millimeters or 0.005 inches in the
experiments described below). However, housing 600 has an
elliptical inner surface shaped to reflect the shockwaves that
initially travel backwards from the spark gap into the wall. Doing
so has the advantage of producing, for each shockwave generated at
the spark gap, a first or primary shockwave that propagates from
the spark gap to outlet 640, followed by a secondary shock wave
that propagates first to the elliptical inner wall and is then
reflected back to outlet 640.
[0107] In this embodiment, supports 616 and 620 are not aligned
with (rotated approximately 30 degrees around chamber 612 relative
to) fittings 604, 608. In the embodiment shown, housing 600 has a
hemispherical shape and electrodes 624 are positioned such that an
angle 632 between a central axis 636 through the center of
shockwave outlet 640 and a perimeter 644 of chamber 612 is about 57
degrees. Other embodiments can be configured to limit this angular
sweep and thereby direct the sound waves and/or shockwaves through
a smaller outlet. For example, FIG. 8 depicts a cross-sectional
view of a second embodiment 600a of a spark chamber housing.
Housing 600a is similar to housing 600, with the exception that
fittings 604a, 608a are rotated 90 degrees relative to supports
616a, 620a. Housing 600a also differs in that chamber 612a includes
a hemispherical rear or proximal portion and a frusto-conical
forward or distal portion. In this embodiment, electrodes 624a are
positioned such that such that an angle 632a between a central axis
636a through the center of shockwave outlet 640a and a perimeter
644a of chamber 612a is about 19 degrees.
[0108] FIG. 9 depicts a schematic diagram of an electric circuit
for a protyped pulse-generation system used with the spark chamber
housing of FIGS. 7A-7B in the present experimental procedures. The
schematic includes symbols known in the art, and is configured to
achieve pulse-generation functionality similar to that described
above. The depicted circuit is capable of operating in the
relaxation discharge mode with embodiments of the present shockwave
heads (e.g., 46, 46a, etc.). As shown, the circuit comprises a 110V
alternating current (AC) power source, an on-off switch, a timer
("control block"), a step-up transformer that has a 3 kV or 3000V
secondary voltage. The secondary AC voltage is rectified by a pair
of high voltage rectifiers in full wave configuration. These
rectifiers charge a pair of oppositely polarized 25 mF capacitors
that are each protected by a pair of resistors (100 k.OMEGA. and 25
k.OMEGA.) in parallel, all of which together temporarily store the
high-voltage energy. When the impedance of the shockwave chamber is
low and the voltage charge is high, a discharge begins, aided by
ionization switches, which are large spark gaps that conduct when
the threshold voltage is achieved. A positive and a negative
voltage flows to each of the electrodes so the potential between
the electrodes can be up to about 6 kV or 6000 V. The resulting
spark between the electrodes results in vaporization of a portion
of the liquid into a rapidly-expanding gas bubble, which generates
a shock wave. During the spark, the capacitors discharge and become
ready for recharge by the transformer and rectifiers. In the
experiments described below, the discharge was about 30 Hz,
regulated only by the natural rate of charge and discharge--hence
the term "relaxation oscillation." In other embodiments, the
discharge rate can be as higher (e.g., as high as 100 Hz, such as
for the multi-gap configuration of FIG. 5.
[0109] A total of 6 excised, tattooed primate skin samples were
obtained, and specimens were segregated, immobilized on a
substrate, and placed in a water bath. A total of 4 tattooed
specimens and 4 non-tattooed specimens were segregated, with one
each of the tattooed and non-tattooed specimens held as controls.
Shock chamber housing 600 was placed over each of the excised
specimens and voltage pulses applied to electrodes 624 at full
power for various durations. Shockwaves were generated at a voltage
of about 5-6 kV and about 10 mA, which resulted in a power level of
about 50 W per pulse, and the shockwaves were delivered a rate of
about 10 Hz. For purposes of the described experiments, multiple
periods of exposure were used and the results observed after the
cumulative periods of exposure (e.g., cumulative total time of
10-20 minutes) as indicative of a longer period of exposure and/or
a period of exposure at a greater pulse rate. The immediate results
observed in the water bath showed a formation of coagulum around
the edge of the samples, which was believed to indicate the flow of
residual blood from the repeated shock waves. All specimens were
put into formalin for histopathology. A histopathologist reported
an observed disruption of cell membranes and a dispersal of the
tattoo particles for tattoo pigment-containing macrophages in the
treated tissue. Changes to adjacent tissue--such as thermal damage,
rupture of basal cells or formation of vacuoles--were not observed.
The specimen showing the most obvious disruption, which could be
readily seen by an untrained eye, had the highest shock wave
exposure time duration of the group. This is strongly suggestive of
a threshold effect that could be further illustrated as power
and/or time are increased.
[0110] Additional in-vitro monkey, and in-vivo monkey and porcine,
tests were subsequently performed using a further embodiment 38b of
the present (e.g., handheld) probes for use with some embodiments
of the present EH shockwave generating systems and apparatuses
depicted in FIGS. 11-13C. Probe 38b is similar in some respects to
probes 38 and 38a, and the differences are therefore primarily
described here. In this embodiment, probe 38b comprises: a housing
14b defining a chamber 18b and a shockwave outlet 20b; a liquid
(54) disposed in chamber 18b; a plurality of electrodes (e.g., in
spark head or module 22d) configured to be disposed in the chamber
to define one or more spark gaps; and is configured to be coupled
to a pulse-generation system 26 configured to apply voltage pulses
to the electrodes at a rate of between 10 Hz and 5 MHz.
[0111] In the embodiment shown, spark head 22d includes a sidewall
or body 120d and a plurality of electrodes 100g that define a spark
gap. In this embodiment, probe 38b is configured to permit liquid
to be circulated through chamber 18b via liquid connectors or ports
112b and 116b, one of which is coupled to spark head 22d and the
other of which is coupled to housing 14b, as shown. In this
embodiment, housing 14b is configured to receive spark head 22d, as
shown, such that housing 14b and sidewall or body 120d cooperate to
define chamber 18b (e.g., such that spark head 22d and housing 14b
include a complementary parabolic surfaces that cooperate to define
the chamber). In this embodiment, housing 14b and spark head 22d
includes acoustically-reflective liners 700, 704 that cover their
respective surfaces that cooperate to define chamber 18b. In this
embodiment, sidewall or body 120d of spark head 22d includes a
channel 188b (e.g., along a central longitudinal axis of spark head
22d) extending between liquid connector 112b and chamber 18b and
aligned with the spark gap between electrodes 100g such that
circulating water will flow in close proximity and/or through the
spark gap. In the embodiment shown, housing 14b includes a channel
192b extending between connection 116b and chamber 18b. In this
embodiment, spark head 22 d includes a groove 708 configured to
receive a resilient gasket or O-ring 140a to seal the interface
between spark head 22d and housing 14b, and housing 14b includes a
groove 712 configured to receive a resilient gasket or O-ring 140b
to seal the interface between housing 14b and cap member 136b when
cap member 136b is secured to housing 14b by ring 716 and retaining
collar 144b.
[0112] In the embodiment shown, electrodes 100g each includes a
flat bar portion 724 and a perpendicular cylindrical portion 728
(e.g., comprising tungsten for durability) in electrical
communication (e.g., unitary with) bar portion 724 such that
cylindrical portion 728 can extend through a corresponding opening
732 in spark head 22d into chamber 18b, as shown. In some
embodiments, part of the sides of cylindrical portion 728 can be
covered with an electrically insulative and/or resilient material
(e.g., shrink wrap) such as, for example, to seal the interface
between portion 728 and housing 120b. In this embodiment, housing
120b also includes longitudinal grooves 732 configured to receive
bar portions 724 of electrodes 100g. In the embodiment shown,
housing 38g also includes set screws 736 positioned align with
cylindrical portions 732 of electrodes 100g when spark head 22d is
disposed in housing 38g, such that set screws 736 can be tightened
to press cylindrical portions 736 inward to adjust the spark gap
between the cylindrical portions of electrodes 100g. In some
embodiments, spark head 22d is permanently adhered to housing 38b;
however, in other embodiments, spark head 22d may be removable from
housing 38b such as, for example, to permit replacement of
electrodes 100g individually or as part of a new or replacement
spark head 22d.
[0113] FIG. 14 depicts a schematic diagram of a second embodiment
of an electric circuit for a prototyped pulse-generation system.
The circuit of FIG. 14 is substantially similar to the circuit of
FIG. 9 with the primary exception that the circuit of FIG. 14
includes an arrangement of triggered spark gaps instead of
ionization switches, and includes certain components with different
properties than corresponding components in the circuit of FIG. 9
(e.g., 200 k.OMEGA. resistors instead of 100 k.OMEGA. resistors).
In the circuit of FIG. 14, block "1" corresponds to a primary
controller (e.g., processor) and block "2" corresponds to a voltage
timer controller (e.g., oscillator), both of which may be combined
in a single unit in some embodiments.
[0114] In the additional in-vitro monkey tests, probe 38b of FIGS.
11-13C was placed over the tattoos of respective subjects and was
powered by the circuit of FIG. 14. In the monkey tests, voltage
pulses were applied to electrodes 100g at varying frequencies
(30-60 Hz) for varying durations of one minute up to ten minutes.
At the greatest power, shockwaves were generated at a voltage of
about 0.5 kV (between a maximum of about +0.4 kV and a minimum of
about -0.1 kV) and a current of about 2300 A (between a maximum of
about 1300 A and a minimum of about -1000 A), which resulted in a
total power of about 500 kW per pulse and delivered energy of about
420 mJ per pulse, and the shockwaves were delivered a rate of about
30 Hz. As with previous in-vitro tests, a histopathologist reported
an observed disruption of cell membranes and a dispersal of the
tattoo particles for tattoo pigment-containing macrophages in the
treated tissue. Changes to adjacent tissue--such as thermal damage,
rupture of basal cells or formation of vacuoles--were not observed.
The specimens showing the most obvious disruption were those with
the highest power and shock wave exposure time duration. These
results suggested that increased power and increased number of
shocks (resulting in an overall increase in delivered power) caused
an increased disruption of pigments, which was consistent with the
earlier in-vitro tests.
[0115] In the in-vivo tests, probe 38b of FIGS. 11-13C was placed
over the tattoos of respective subjects and was powered by the
circuit of FIG. 14. In the monkey tests, voltage pulses were
applied to electrodes 100g at full power for a duration of two
minutes and repeated once per week for six weeks. Shockwaves were
generated at a voltage of about 0.5 kV (between a maximum of about
+0.4 kV and a minimum of about -0.1 kV) and a current of about 2300
A (between a maximum of about 1300 A and a minimum of about -1000
A), which resulted in a total power of about 500 kW per pulse and
delivered energy of about 420 mJ per pulse, and the shockwaves were
delivered a rate of about 30 Hz. In-vivo porcine tests were
similar, except that shockwaves were applied for duration of four
minutes at each application. One week after the sixth application
of shockwaves, biopsies were taken from each tattoo. All specimens
were put into formalin for histopathology. A histopathologist
reported an observed disruption of cell membranes and a dispersal
of the tattoo particles for tattoo pigment-containing macrophages
in the treated tissue, with a relatively greater dispersal for
specimens that underwent 4-minute treatments than those that
underwent 2-minute treatments. Changes to adjacent tissue--such as
thermal damage, rupture of basal cells or formation of
vacuoles--were not observed. These results were consistent with
those observed for the in-vitro monkey tests. Overall, these
studies suggested that increased power and increased number of
shocks (resulting in an overall increase in delivered power--e.g.,
due to increased duration of treatment).
Methods
[0116] Examples of maladies and/or conditions that involve
particles agglomerated in cellular structures include cancer,
crystalline micro-particles in the musculoskeletal system, or
removal of tattoos. These are merely no limiting exemplary
conditions that can be treated or addressed by rupturing or
destruction of cells containing particle agglomerates. In some
embodiments, destruction of the cells containing particle
agglomeration may be caused by non-thermal cell membrane
degradation of the specific cells secondary to nonlinear processes
accompanying propagation of high frequency shock waves, as
discussed above.
[0117] Some general embodiments of the present methods comprise:
delivering a plurality of electro-hydraulically generated (e.g.,
via one or more of the present apparatuses) shock waves to at least
one cellular structure comprising at least one region of
heterogeneity until the at least one cellular structure ruptures.
In some embodiments, the shock waves are delivered for no more than
30 minutes in a 24-hour period. In some embodiments, the shock
waves are delivered for no more than 20 minutes in a 24-hour
period. In some embodiments, between 200 and 5000 shockwaves are
delivered in between 30 seconds and 20 minutes at each of a
plurality of positions of a shockwave outlet.
[0118] A. Tattoos
[0119] Tattoos are essentially phagocytosing cells such as
fibroblast cells, macrophages, and the like that contain
agglomerates of ink particles. Because the captured ink particles
are denser than the biological structures of the cells, tattoos or
cells containing ink particles have a large difference in
elasticity in its structure. When subject to shock waves, the cells
containing ink particles are subject to greater mechanical strain
as compared to other cells that do not contain dense particles.
Shock waves can be configured to be delivered at an optimal
frequency and amplitude to accelerate the ink particles
sufficiently to rupture the particular cells while leaving intact
fibroblast cells that do not have the particular elasticity
difference. The details of tattoos and biological process of
removal of released from cells are discussed further below.
[0120] Tattoo inks and dyes were historically derived from
substances found in nature and generally include a heterogeneous
suspension of pigmented particles and other impurities. One example
is India ink, which includes a suspension of carbon particles in a
liquid such as water. Tattoos are generally produced by applying
tattoo ink into the dermis, where the ink generally remains
substantially permanently. This technique introduces the pigment
suspension through the skin by an alternating pressure-suction
action caused by the elasticity of the skin in combination with the
up-and-down movement of a tattoo needle. Water and other carriers
for the pigment introduced into the skin diffuse through the
tissues and are absorbed. For the most part, 20%-50% of the pigment
is disseminated into the body. However, the remaining portion of
the insoluble pigment particles are deposited in the dermis where
placed. In tattooed skin, pigment particles generally are
phagocytized by cells resulting in pigment agglomerates in the
cytoplasm of the cells (i.e., in the membrane-bound structures
known as secondary lysosomes). Resulting pigment agglomerates
("particle agglomerates") may range up to a few micrometers in
diameter. Once the skin has healed, the pigment particles remain in
the interstitial space of the skin tissue within the cells. Tattoo
inks generally resist elimination due to the cells immobility due
to the relatively large amount of insoluble pigment particles in
the cells. A tattoo may fade over time, but will generally remain
through the life of the tattooed person.
[0121] Tattoo inks typically comprise aluminum (87% of the
pigments), oxygen (73% of the pigments), titanium (67% of the
pigments), and carbon (67% of the pigments). The relative
contributions of elements to the tattoo ink compositions were
highly variable between different compounds. At least one study has
determined the particle size for three commercial tattoo inks as
shown in Table 1:
TABLE-US-00001 TABLE 1 Tattoo Pigment Particle Size Color Mean
Diameter Std deviation Viper Red 341 nm 189 nm Agent Orange 228 nm
108 nm Hello yellow 287 nm 153 nm
[0122] B. Tattoo Removal
[0123] In conventional tattooing (decorative, cosmetic, and
reconstructive), once the pigment or dye has been administered into
the dermis to form a tattoo, the pigment or dye generally remains
permanently in place, as discussed above.
[0124] Despite the general permanency of tattoos, individuals may
wish to change will remove tattoos for a variety of reasons. For
example, over time people may have a change of heart (or mind), and
may desire to remove or change the design of a decorative tattoo.
By way of another example, an individual with cosmetic tattooing,
such as eyeliners, eyebrows, or lip coloring, may wish to change
the color or area tattooed as fashion changes. Unfortunately, there
is currently no simple and successful way to remove tattoos.
Currently, methods of removing traditional tattoos (e.g.,
pigment-containing skin) may include salabrasion, cryosurgery,
surgical excision, and CO2-laser. These methods may require
invasive procedures associated with potential complications, such
as infections, and usually results in conspicuous scarring. More
recently, the use of Q-switched lasers has gained wide acceptance
for the removal of tattoos. By restricting pulse duration, ink
particles generally reach very high temperatures resulting in the
destruction of the tattoo ink pigment-containing cells with
relatively minimal damage to adjacent normal skin. This
significantly decreases the scarring that often results after
nonselective tattoo removal methods, such as dermabrasion or
treatment with carbon dioxide laser. The mechanisms of tattoo
removal by Q-switch laser radiation may still be poorly understood.
It is thought that Q-switch laser allow for more specific removal
of tattoos by the mechanisms of selective photothermolysis and
thermokinetic selectivity. Specifically, it is thought that the
pigment particles in cells are able to absorb the laser light
causing heating of the particles resulting thermal destruction of
the cells containing said particles. The destruction of these cells
results in the release of particles which can then be removed from
the tissue through normal absorptive processes.
[0125] While the Q-switch laser may be better than some
alternatives for the removal of tattoos, it is not perfect. Some
tattoos are resistant to all laser therapies despite the predicted
high particle temperatures achieved through selective
photothermolysis. Reasons cited for failure of some tattoos to
clear include the absorption spectrum of the pigment, the depth of
pigment, and structural properties of some inks. Adverse effects
following laser tattoo treatment with the Q-switched ruby laser may
include textural changes, scarring, and/or pigmentary alteration.
Transient hypopigmentation and textural changes have been reported
in up to 50 and 12%, respectively, of patients treated with the
Q-switched alexandrite laser. Hyperpigmentation and textural
changes are infrequent adverse effects of the Q-switched Nd:YAG
laser and the incidence of hypopigmentary changes are generally
lower than with the ruby laser. The development of localized and
generalized allergic reactions is also impossible (even if unusual)
complication of tattoo removal with the Q-switched ruby and Nd:YAG
lasers. Additionally, laser treatment may be painful, such that use
of a local injection with lidocaine or topical anesthesia cream
typically is used prior to laser treatment. Finally, laser removal
generally requires multiple treatment sessions (e.g., 5 to 20) and
may require expensive equipment for maximal elimination. Typically,
since many wavelengths are needed to treat multicolored tattoos,
not one laser system can be used alone to remove all the available
inks and combination of inks. Even with multiple treatments, laser
therapy may only be able to eliminate 50-70% of the tattoo pigment,
resulting in a residual smudge.
[0126] Some embodiments of the present methods comprise: directing
electro-hydraulically generated shock waves (e.g., from an
embodiment of the present apparatuses) to cells of a patient; where
the shock waves are configured to cause particles to rupture one or
more of the cells. Some embodiments comprise: providing an
embodiment of the present apparatuses; actuating apparatus to
former shockwaves configured to cause particles within a patient to
rupture one or more cells of the patient; and directing the
shockwaves to cells of a patient such that the shockwaves cause
particles to rupture one or more of the cells (e.g., such as by
degradation of the cell wall or membrane). In some embodiments, the
one or more shockwaves are configured to have substantially no
lasting effect on cells in the absence of particles (e.g.,
configured to cause substantially no permanent or lasting damage to
cells that are not close enough to particles to be damaged by the
particles in the presence of the shockwaves).
[0127] Some embodiments of the present methods comprise focusing
the one or more shockwaves a specific region of tissue that
comprises the cells. In some embodiments the region of tissue at
which the one or more shockwaves is focused is a depth beneath the
patient's skin. The shockwaves can be focused by any of a variety
of mechanisms. For example, a surface of the present apparatuses
that is configured to contact a patient during use (e.g., of outlet
member 70a) may be shaped (e.g., convex) to focus or shaped (e.g.,
convex) to disperse shockwaves, such as, for example, to narrow the
area to which shockwaves are directed or expand the area to which
shockwaves are directed. Focusing the shockwaves may result in
higher pressures at targeted cells, such as, for example, pressures
of 10 MPa, 15-25 MPa, or greater. In some embodiments, the convex
outer shape is configured to tension a portion of a patient's skin
as the outlet member is pressed against the skin.
[0128] Some embodiments of the present methods further comprise:
identifying target cells of the patient to be ruptured (e.g., prior
to directing the one or more shockwaves to the target cells). In
various embodiments, the target cells can comprise any of a variety
of target cells, such as, for example, target cells comprising a
condition or malady involving cellular particle agglomerates. For
example, the target cells may comprise: a tattoo, musculoskeletal
cells comprising crystalline micro-particles, hair follicles that
contain keratin protein, dental follicles that contain enamel,
cancer cells, and/or the like. By way of another example, target
cells may comprise one or more skin maladies selected from the
group consisting of: blackheads, cysts, pustules, papules, and
whiteheads.
[0129] In some embodiments, the particles can comprise non-natural
particles. One example of non-natural particles includes tattoo
pigment particles, such as are commonly disposed in the human
dermis to create a tattoo. In some embodiments, the pigments can
comprise an element with anatomic number of less than 82. In some
embodiments, the particles can comprise any one or combination of:
gold, titanium dioxide, iron oxide, carbon, and/or gold. In some
embodiments, the particles have a mean diameter of less than 1000
nm (e.g., less than 500 nm and/or less than 100 nm).
[0130] FIG. 10 illustrates one embodiment of a method 700 of using
apparatus 10 to direct shockwaves to target tissue. In the
embodiment shown, method 700 comprises a step 704 in which target
cells 708 of a patient's tissue 712 are identified for treatment.
For example, tissue 712 can comprise skin tissue, and/or target
cells 708 can comprise cells containing tattoo pigment within or
near skin tissue. In the embodiment shown, method 700 also
comprises a step 716 in which a probe or handpiece 38 is disposed
adjacent tissue 712 and/or tissue 716, such that shockwaves
originating in probe 38 can be directed toward the target cells
708. In the embodiment shown, method 700 also comprises a step 720
in which a pulse-generation system 26 is coupled to probe 38. In
the embodiment shown, method 700 also comprises a step 724 in which
pulse-generation system 26 is activated to generate sparks across
electrodes within probe 38 to generate shockwaves in probe 38 for
delivery to target cells 708, as shown. In the embodiment shown,
method 700 also comprises an optional step 728 in which
pulse-generation system 26 is de-coupled from probe 38, and probe
38 is removed from or moved relative to tissue 712. In the
embodiment shown, target cells 708 are omitted from step 728,
representing their destruction. Other embodiments of the present
methods may comprise some or all of the steps illustrated in FIG.
10.
[0131] C. Methods of Removing Tissue Markings
[0132] In some embodiments of the present methods of diminishing
tissue markings (e.g., tattoos) caused by pigments in dermis tissue
involve the use of one of the present apparatuses. In such methods,
high-frequency shockwaves are transmitted to and into a patient's
skin, such that when the shock waves generated from the apparatus
of the present disclosure reach the dermal cells and vibrate or
accelerate the intradermal particles, these particles experience
movement relative cell membranes that can lead to fatigue
degradation and rupturing of cells, thereby releasing the pigment
particles. Released particles can then be removed from the
surrounding tissue through normal absorptive processes of the
patient's body. In some embodiments, one of the present apparatuses
can be disposed adjacent to, and/or such that the shock waves from
the apparatus are directed to the tissue site having the tattoo,
other tissue markings, or other cellular structures containing
particle agglomerates. To cause particle alteration (e.g., cell
degradation sufficient to release particles for absorption), the
shock waves can be delivered to a specific area for a period of
time long enough to rupture cells containing and/or adjacent to the
pigment particles such that the pigment particles are released. In
some embodiments the present apparatuses have a focus or effective
area that may be relatively smaller than a tattoo, such that the
apparatus may be periodically and are sequentially focused are
directed at different areas of a tattoo to cause a reduction in
perceptible pigments over the entire area of the tattoo. For
instance, the parameters of the embodiments of the apparatus
disclosed here can be modified to achieve the desire number of
shocks delivered to a particular site in a desired amount of time.
For instance, in one embodiment, shock waves are produced from
acoustic waves with frequency of at least 1 MHz according to
aspects of the present disclosure and exposed to a particular
treatment site for the appropriate period of time to deliver at
least about 100, 200, 300, 400, 500, or 1000 shock waves to the
treatment site. The shock waves can be delivered all at once or
through intervals (e.g., bursts) of shock waves (such as 5, 10, 15,
20, 25, 30, 40, 50, etc. shock waves at a time). The appropriate
interval and time between the interval can be modified and/or
determined to achieve the desired effect at the treatment site,
e.g., rupture of the targeted cellular structures. It is understood
that if acoustic waves with higher frequency are used, such as 2
MHz, 3 MHz, 4 MHz, or 5 MHz, the treatment time can be adjusted,
likely shorter exposure time, to achieve the desired amount of
shock waves delivered to the treatment area.
[0133] As will be appreciated by those of ordinary skill in the
art, in embodiments of the present methods for removing tattoos,
the particles affected by the shock waves can comprise tattoo
pigment (particles), such as may, for example, be at least
partially disposed between and/or within skin cells of the patient.
Such pigment particles may, for example, include at least one or
combination of any of the following: titanium, aluminum, silica,
copper, chromium, iron, carbon, or oxygen.
[0134] The use of high frequency shock waves to remove or reduce
skin markings has many advantages over the use of lasers. For
example, laser treatments for tattoo removal may be very painful.
In contrast, high-frequency shockwaves (e.g., ultrasound
shockwaves) can be configured and/or applied such that tattoos or
other skin markings may be removed or diminished with little if any
pain to the patient, especially, for example, where the shock waves
are targeted or otherwise configured to degrade only cells that
contain tattoo pigments. By way of another example, laser light
directed at tissue has been found to cause damage to or destruction
of surrounding tissues; whereas high-frequency shock waves may be
applied so as to cause little damage or destruction of surrounding
tissues (e.g., because non-tattooed surrounding tissues generally
lack tattoo pigment or other particles that might otherwise
interact with neighboring cells to cause sell degradation).
Finally, laser tattoo removal often requires multiple treatment
sessions (e.g., 5-20 sessions) for maximal tattoo elimination,
and/or often requires the use of expensive equipment. Additionally,
since many wavelengths a laser light may be needed to remove
multicolored tattoos, multiple laser systems may be needed to
remove the variety of available inks and/or combinations of
available inks. As a result, the overall cost of laser tattoo
removal may be prohibitively expensive. Even with multiple
treatments, laser therapy may be limited to eliminating only 50 to
70% of tattoo pigment, and may leave a residual "smudge." In
contrast, high-frequency shockwaves is not dependent upon the color
of tattoo pigments such that therapeutic application of
high-frequency shockwaves does not require different apparatuses
for different colors of pigment, and such that high-frequency
shockwaves may be applied to a relatively large area (e.g., the
entire area of a tattoo), thereby reducing the number of treatment
sessions required to achieve a level of tattoo removal or reduction
that is acceptable to the patient (e.g., 30, 40, 50, 60, 70, 80,
90, 95, or more percent reduction in the perceivable pigment in the
patient's skin).
[0135] In some embodiments, the present methods include the
application of high-frequency shockwaves (e.g. with one or more of
the present apparatuses) and the application of laser light. For
example, some embodiments of the present methods further comprise
directing a beam of light from a Q-switched laser at the target
cells (e.g., tattooed skin). In some embodiments, directing one or
more shockwaves and directing the beam of light are performed in
alternating sequence.
[0136] In some embodiments, the present methods include delivering
one or more chemical or biological agents (e.g., configured to aid
in the removal of tissue markings such as tattoos) to a position at
or near the target cells before, after, and/or simultaneously with
directing the one or more shockwaves to the target cells. For
example, some embodiments of the present methods further comprise
applying a chemical or biological agent to the skin (e.g., before,
after, and/or simultaneously with directing one or more shockwaves
and/or a beam of laser light at the skin). Examples of chemical or
biological agents include: chelators (e.g.,
ethylenediaminetetraacetic acid (EDTA)); immune modulators (e.g.,
Imiquimod [5]); combinations thereof; and/or other suitable
chemical in or biological agents. In various embodiments, chemical
in or biological agents to be delivered transdermally and/or
systemically (e.g., the injection) to the target cells (e.g., may
be applied topically to tattooed skin).
[0137] Some embodiments of the present methods of tattoo removal
include multiple applications of shockwaves to tattooed skin tissue
(e.g., for a duration of at least 1 second (e.g., 10 seconds, or
more), once per week for 6 or more weeks).
[0138] D. Method of Treating Additional Maladies and Conditions
[0139] In addition to tattoo removal, embodiments of the present
methods may include the application of high-frequency shockwaves to
treat a variety of maladies under conditions caused by and/or
including symptoms of cellular particle agglomerates and/or
particles disposed in intracellular spaces and/or interstitial
spaces. For example, such maladies and/or conditions may include:
crystal joint, ligament, tendon and muscle disease, and/or
dermatological maladies involving particle agglomerates including
acne, age spots, etc. Additionally, embodiments of the present
methods may include the application of high-frequency shockwaves
after delivering nanoparticles to a region of the patient that
includes the target cells. For example, in some embodiments,
nanoparticles (e.g., gold nanoparticles) are delivered to a
patient's bloodstream intravenously and permitted to travel to a
region of the patient that includes the target cells (e.g. a
cancerous tumor), such that high-frequency shockwaves can be
directed to the target region to cause the nanoparticles to
interact with and rupture the target cells.
[0140] Further, embodiments of the present apparatuses (e.g.,
apparatus 10) can be used for wrinkle reduction. For example, some
embodiments of the present methods of generating therapeutic shock
waves, comprise: providing any of the present apparatuses (e.g.,
apparatus 10); and actuating the apparatus to generate one or more
shock waves. Some embodiments further comprise: disposing the
apparatus (e.g., outlet end 34 of housing 18) adjacent tissue of a
patient such that at least one shock wave enters the tissue. In
some embodiments, the tissue comprises skin tissue on the face of
the patient.
[0141] In embodiments of the present methods that include directing
particles (e.g., micro-particles and/or nanoparticles) to a
position at or near the target cells (prior to directing shockwaves
to the cells), the particles can comprise: silk, silk fibron,
carbon nanotubes, liposomes, and/or gold nanoshells. For example,
in some embodiments, directing the particles can comprises
injecting into the patient a fluid suspension that includes the
particles. Include suspension may, for example, comprise saline
and/or hyaluronic acid.
[0142] Deposition of crystals and other miscellaneous crystals in
articular and particular tissues can result in a number of disease
states. For example, monosodium urate monohydrate (MSUM) deposition
in a joint may results in gout. As another example, calcium
pyrophosphate dehydrate (CPPD) in joint tissues and fluids may
result in a number of disease conditions, such as, for example,
chondrocalcinosis (i.e., presence of calcium-containing crystals
detected as radiodensities in articular cartilage). By way of
further example, hydroxyapatite (HA) crystal deposition may result
in calcific tendonitis and perarthritis. In some embodiments of the
present methods, the particles may comprise natural particles
(e.g., particles naturally occurring within the body), such as, for
example, crystalline micro-particles such as may be form and/or
become disposed in the musculoskeletal system of a patient. Other
examples of natural particles they may be treated and/or disbursed
in the present methods include: urate crystals, calcium-containing
crystals, and/or hydroxyapatite crystals.
[0143] In embodiments of the present methods for treatment of acne
or other skin-based conditions, the particles may comprise dirt
and/or debris that is disposed in one or more pores of the
patient's skin, and/or may comprise keratin protein disposed of the
patient's skin. In embodiments of the present methods of treating
(e.g., pathological) conditions associated with bone and
musculoskeletal environments and soft tissues by applying
shockwaves can induce localized trauma and cellular apoptosis
(including micro-fractures), or may induce osteoblastic responses
such as cellular recruitment, stimulate formation of molecular
bone, cartilage, tendon, fascia, and soft tissue morphogens and
growth factors, and/or may induce vascular neoangiogenesis.
[0144] Some embodiments of the present methods of treating tumors
or other maladies include multiple applications of shockwaves to
targeted tissue (e.g., a tumor, an area of skin with acne or other
conditions, etc.), such as, for example, for a duration of at least
(e.g., 10 seconds, or more), once per week for 6 or more weeks.
[0145] The above specification and examples provide a description
of the structure and use of exemplary embodiments. Although certain
embodiments have been described above with a certain degree of
particularity, or with reference to one or more individual
embodiments, those skilled in the art could make numerous
alterations to the disclosed embodiments without departing from the
scope of this invention. As such, the various illustrative
embodiments of the present devices are not intended to be limited
to the particular forms disclosed. Rather, they include all
modifications and alternatives falling within the scope of the
claims, and embodiments other than the one shown may include some
or all of the features of the depicted embodiment. For example,
components may be combined as a unitary structure. Further, where
appropriate, aspects of any of the examples described above may be
combined with aspects of any of the other examples described to
form further examples having comparable or different properties and
addressing the same or different problems. Similarly, it will be
understood that the benefits and advantages described above may
relate to one embodiment or may relate to several embodiments.
[0146] The claims are not intended to include, and should not be
interpreted to include, means-plus- or step-plus-function
limitations, unless such a limitation is explicitly recited in a
given claim using the phrase(s) "means for" or "step for,"
respectively.
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