U.S. patent application number 14/174011 was filed with the patent office on 2014-08-07 for application of energy with cooling elements for skin treatment.
The applicant listed for this patent is Michael Kreindel. Invention is credited to Michael Kreindel.
Application Number | 20140221990 14/174011 |
Document ID | / |
Family ID | 35944387 |
Filed Date | 2014-08-07 |
United States Patent
Application |
20140221990 |
Kind Code |
A1 |
Kreindel; Michael |
August 7, 2014 |
APPLICATION OF ENERGY WITH COOLING ELEMENTS FOR SKIN TREATMENT
Abstract
A system and method for simultaneously heating a plurality of
discrete skin volumes to a coagulation temperature. The system
comprises an applicator containing an electrode having a plurality
of spaced apart protruding conducting elements configured to
contact the skin surface at a plurality of discrete locations. A
controller applies a voltage to the electrode so as to
simultaneously heat a plurality of skin volumes to a coagulation
temperature when the applicator is applied to the skin surface.
Inventors: |
Kreindel; Michael; (Haifa,
IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Kreindel; Michael |
Haifa |
|
IL |
|
|
Family ID: |
35944387 |
Appl. No.: |
14/174011 |
Filed: |
February 6, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13925832 |
Jun 25, 2013 |
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14174011 |
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12876765 |
Sep 7, 2010 |
8579896 |
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13925832 |
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12702647 |
Feb 9, 2010 |
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12876765 |
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12702723 |
Feb 9, 2010 |
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12702647 |
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10931271 |
Sep 1, 2004 |
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12702723 |
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13028216 |
Feb 15, 2011 |
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10931271 |
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10931271 |
Sep 1, 2004 |
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13028216 |
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Current U.S.
Class: |
606/20 ;
606/33 |
Current CPC
Class: |
A61B 18/14 20130101;
A61B 2018/1425 20130101; A61B 2018/143 20130101; A61B 18/18
20130101; A61B 18/1477 20130101; A61B 2018/00452 20130101; A61B
2018/0293 20130101; A61B 2018/1467 20130101; A61B 18/0218
20130101 |
Class at
Publication: |
606/20 ;
606/33 |
International
Class: |
A61B 18/18 20060101
A61B018/18; A61B 18/02 20060101 A61B018/02 |
Claims
1. A skin treatment apparatus for selectively treating volumes of
skin tissue, comprising: a plurality of spaced apart conducting
elements configured to contact a skin surface at a plurality of
discrete locations, the plurality of conducting elements being
configured to receive energy from a radio frequency energy
generator; and a cooling element configured to cool regions between
the plurality of conducting elements so as to maintain the skin
surface between the plurality of discrete locations below a
coagulation temperature when the plurality of conducting elements
are energized.
2. The apparatus according to claim 1, wherein the cooling element
comprises a cooling fluid in contact with the regions between the
plurality of conducting elements.
3. The apparatus according to claim 2, wherein the cooling element
comprises a plurality of tubes through which the cooling fluid
circulates, the plurality of tubes being located in the regions
between the plurality of conducting elements.
4. The apparatus according to claim 1, wherein the cooling element
is configured to apply a cryogen spray to the skin surface in the
regions between the plurality of conducting elements.
5. The apparatus according to claim 1, wherein the plurality of
conducting elements are terminated by sharp tips that are
configured to penetrate the skin surface at the plurality of
discrete locations.
6. The apparatus according to claim 1, wherein the plurality of
conducting elements are terminated by blunt tips that are not
configured to penetrate into the skin surface at the plurality of
discrete locations.
7. An applicator for selective treatment of discrete skin volumes,
said applicator comprising: a plurality of conducting elements
configured to receive energy from a radio frequency energy
generator and to contact a skin surface at a plurality of discrete
locations to apply the received energy to the plurality of discrete
locations of the skin surface, the plurality of conducting elements
extending from a flat surface and being spaced apart from one
another with regions of the flat surface interposed between the
plurality of conducting elements; and a cooling element configured
to cool the regions of the flat surface between the plurality of
conducting elements so as to maintain the skin surface between the
plurality of discrete locations below a coagulation temperature
when the plurality of conducting elements are energized and brought
into contact with the skin surface.
8. The applicator according to claim 7, wherein the cooling element
comprises a cooling fluid in contact with the regions of the flat
surface interposed between the plurality of conducting
elements.
9. The applicator according to claim 8, wherein the cooling element
comprises a plurality of tubes through which the cooling fluid
circulates, the plurality of tubes being located in the regions of
the flat surface interposed between the plurality of conducting
elements.
10. The applicator according to claim 7, wherein the cooling
element is configured to apply a cryogen spray to the skin surface
in the regions of the flat surface interposed between the plurality
of conducting elements.
11. The applicator according to claim 7, wherein the plurality of
conducting elements are terminated by sharp tips that are
configured to penetrate the skin surface at the plurality of
discrete locations.
12. The applicator according to claim 7, wherein the plurality of
conducting elements are terminated by blunt tips that are not
configured to penetrate into the skin surface at the plurality of
discrete locations.
13. The applicator according to claim 7, wherein the plurality of
conducting elements are configured to apply the received energy to
the plurality of discrete locations of the skin surface with a
pulse duration of less than 200 ms.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is being filed under 35 USC 111 and is a
continuation of the following U.S. patent application Ser. No.
13/925,832 filed on Jun. 25, 2013, which is a continuation of Ser.
No. 12/876,765 filed on Sep. 7, 2010 and issued as U.S. Pat. No.
8,579,896 on Nov. 12, 2013, which is a continuation of Ser. No.
12/702,647 filed on Feb. 9, 2010, which is a continuation of Ser.
No. 12/702,723 filed on Feb. 9, 2010 and which is now abandoned,
which is a continuation of Ser. No. 10/931,271 filed on Sep. 1,
2004 now abandoned; and Ser. No. 13/028,216 filed on Feb. 15, 2011,
which is a continuation of Ser. No. 10/931,271 filed on Sep. 1,
2004 and is now abandoned. Each of these applications is
incorporated herein by reference in their entirety.
FIELD OF THE INVENTION
[0002] The invention relates to methods and systems for skin
treatment.
BACKGROUND OF THE INVENTION
[0003] Directed damage of the skin is used to stimulate regrowth of
collagen and to improve skin appearance. A well known method of
directed damage is ablating the epidermis using laser radiation
having wavelengths strongly absorbed by water so as to heat the
water to above boiling temperature. Typical lasers used for
epidermis ablation are CO.sub.2 and Er:YAG lasers. Ablating the
epidermis using RF (radiofrequency) current is described in U.S.
Pat. No. 6,309,387. This treatment significantly reduces wrinkles
and improves the skin appearance. The main disadvantages of skin
resurfacing are the long healing period that can be over a month
long and the high risk of dischromia. These disadvantages have
reduced the popularity of ablative skin resurfacing in recent
years.
[0004] Non-ablative skin resurfacing is based on heating of the
dermis to a sub-necrotic temperature with simultaneous cooling of
the skin surface. U.S. Pat. No. 5,810,801 describes penetrating the
dermis with infrared laser radiation with dynamic cooling of the
skin surface using a cryogen spray.
[0005] Wrinkles are created in skin due to the breakage of collagen
fibers and to the penetration of fat into the dermal structure.
Thus, destroying adipose cells and structure, can improve the
surface structure. However, most wrinkle treatment methods target
the collagen and do not have a significant effect on deep wrinkles
Radio frequency (RF) energy has been used for the treatment of the
epidermal and dermal layers of the skin. For example, U.S. Pat. No.
6,749,626 describes use of RF for collagen formation in dermis.
This patent describes a method for collagen scar formation. U.S.
Pat. Nos. 6,470,216, 6,438,424, 6,430,446, and 6,461,378 disclose
methods and apparatuses for affecting the collagen matrix using RF
with special electrode structures together with cooling and
smoothing of the skin surface. U.S. Pat. Nos. 6,453,202, 6,405,090,
6,381,497, 6,311,090, 5,871,524, and 6,452,912 describe methods and
apparatuses for delivering RF energy to the skin using a membrane
structure. U.S. Pat. Nos. 6,453,202 and 6,425,912 describe methods
and apparatuses for delivering RF energy and creating a reverse
temperature gradient on the skin surface. Although a non-ablative
treatment is much safer and does not scar the skin tissue, the
results of non-ablative treatments are less satisfactory.
[0006] A method described in U.S. patent application No.
20030216719 attempts to maintain the efficiency of ablative
treatment with a shorter healing time and a lower risk of adverse
effects. The device described in that patent coagulates discrete
regions of the skin where the regions have a diameter of tens of
micrometers and the distance between the regions is larger than the
regions themselves. This treatment provides skin healing within a
few days but the results are very superficial and less spectacular
than with CO.sub.2 laser treatment, even after multiple
treatments.
[0007] U.S. Pat. No. 6,277,116 describes a method of applying
electromagnetic energy to the skin through an array of electrodes
and delivery electrolyte using a microporous pad.
[0008] A device for ablation of the skin stratum corneum using RF
electrodes is described in U.S. Pat. Nos. 6,711,435, 6,708,060,
6,611,706, and 6,597,946. However, the parameters of this device
are optimized for the ablation of the stratum corneum so as to
enhance drug penetration into the skin, and not for thermal
collagen remodeling.
SUMMARY OF THE INVENTION
[0009] The present invention provides a system and method for
simultaneously heating skin at a plurality of discrete regions of
the skin. The invention may be used for collagen remodeling. In
accordance with the invention RF energy is applied to the skin at a
plurality of discrete locations on the skin. The RF energy is
applied using an electrode having a plurality of spaced apart
protruding conducting pins. When the electrode is applied to the
skin surface, each protruding conducting pin contacts the skin
surface at a different location, so that the plurality of pins
contacts the skin at a plurality of discrete locations. An RF
voltage is then applied to the electrode so as to generate an
electric current in the skin that heats the skin to a coagulation
temperature simultaneously at a plurality of discrete regions of
the skin. Coagulation temperatures are typically in the range of
about 60.degree. C. to about 70.degree. C.
[0010] The protruding pins may have blunt tips which do not
penetrate into the skin when the electrode is applied to the skin.
In this case, the discrete regions of treated skin are located at
the skin surface in the epidermis. Alternatively, the pins may have
sharp tips that allow the protruding pin to penetrate the skin into
the dermis. In this way, the discrete regions of treated skin are
located in the dermis.
[0011] In another embodiment, the protruding elements are provided
with sharp tips that allow the elements to penetrate into the skin.
After application of the RF current in the skin, the protruding
elements are pressed into the skin and an electrical current is
then generated that coagulates tissue in the vicinity of the tip of
each protruding element. The mechanical properties of the skin are
changed after coagulation and the protruding elements may penetrate
inside the skin without excessive pressure. A pre-pulse of RF
energy can be applied to the skin in order to soften the skin
tissue so as to facilitate penetration of the protruding elements
into the skin.
[0012] The surface of the skin may be pre-cooled and/or cooled
during the treatment to avoid damage to the skin in the area
between protruding elements Skin cooling may be provided by contact
cooling or by applying a pre-cooled liquid or cryogen spray.
[0013] The invention may be used in wrinkle treatment, collagen
remodeling, skin tightening, loose skin treatment, sub-cutaneous
fat treatment or skin resurfacing.
[0014] Thus in its first aspect, the invention provides a system
for simultaneously heating a plurality of discrete skin volumes to
a coagulation temperature, comprising: [0015] (a) an applicator
comprising an electrode having a plurality of spaced apart
protruding conducting elements configured to contact the skin
surface at a plurality of discrete locations; and [0016] (b) a
controller configured to apply a voltage to the electrode so as to
simultaneously heat a plurality of skin volumes to a coagulation
temperature when the applicator is applied to the skin surface.
[0017] In its second aspect, the invention provides a method for
simultaneously heating a plurality of discrete skin volumes to a
coagulation temperature, comprising: [0018] (a) applying an
applicator to the skin surface, the applicator comprising an
electrode having a plurality of spaced apart protruding conducting
elements configured to contact the skin surface at a plurality of
discrete locations; and [0019] (b) applying a voltage to the
electrode so as to simultaneously heat a plurality of skin volumes
to a coagulation temperature.
[0020] In the case when protruding part of the electrode penetrates
within the skin the size of protruding elements should be small
enough to avoid significant damage of the skin surface. Preferable
size of protruding elements is from 10 to 200 microns and
coagulation depth can be varied from 100 microns up to 2 mm for
invasive electrodes.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] In order to understand the invention and to see how it may
be carried out in practice, preferred embodiments will now be
described, by way of non-limiting examples only, with reference to
the accompanying drawings, in which:
[0022] FIG. 1 shows a system for treating skin simultaneously at a
plurality of discrete regions of skin, in accordance with the
invention;
[0023] FIGS. 2A and 2b (collectively referred to as FIG. 2 in the
description) shows an applicator for use in the system of FIG. 1
with FIG. 2A showing the applicator alone and FIG. 2B showing the
applicator being applied to a target tissue area;
[0024] FIG. 3 shows a second applicator for use in the system of
FIG. 1; and
[0025] FIG. 4 shows a third applicator for use in the system of
FIG. 1.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0026] FIG. 1 shows a system for applying RF energy to a plurality
of discrete regions of skin in accordance with the invention. The
system includes an applicator 13, to be described in detail below,
configured to apply RF energy simultaneously to a plurality of
discrete regions of skin of an individual 22. The applicator 13 is
connected to a control unit 11 via a cable 12. The control unit 11
includes a power source 18. The power source 18 is connected to an
RF generator 15 that is connected to electrodes in the applicator
13 via wires in the cable 12. The control unit 11 has an input
device such as a keypad 10 that allows an operator to input
selected values of parameters of the treatment, such as the
frequency, pulse duration and intensity of the RF energy. The
control unit 11 optionally contains a processor 9 for monitoring
and controlling various functions of the device.
[0027] FIGS. 2A and 2b (collectively referred to as FIG. 2 in the
description) shows an applicator for use in the system of FIG. 1
with FIG. 2A showing the applicator alone and FIG. 2B showing the
applicator being applied to a target tissue area. FIG. 2 shows an
applicator 13a that may be used for the applicator 13 in accordance
with one embodiment of the invention. The applicator 13a comprises
an electrode 1 from which a plurality of protruding conducting
elements 5 extend. Each protruding element 5 (referred to herein as
a "pin") terminates in a tip 7 having a high curvature. The
electrical current from the tips is much higher than from flat
parts 6 of the electrode. Skin volumes 4 around the tips 7 (shown
in FIG. 2B) are therefore heated to a much higher temperature than
the surrounding dermis 3 and epidermis 2, so that the skin volumes
4 may be heated to a coagulation temperature, while the skin
temperature in the outside the volumes 4 are not heated to a
coagulation temperature. The electrical energy is adjusted to
selectively damage skin adjacent to tips so that the treatment of
the skin occurs simultaneously at a plurality of discrete volumes
4. The pulse duration is preferably short enough to prevent
significant heat diffusion far from the tips. In order to limit
significant heat transfer from the tips, the pulse duration should
preferably not exceed 200 ms. The selectivity of the treatment can
be improved by electrode cooling of the skin surface. Cooling also
causes a more uniform heat distribution at the tips. This can be
achieved by circulating a cooling fluid through tubes 8 in the flat
regions 6 between the pins 5. The electrode 1 is contained in a
housing 10 connected to the cable 12. The cable 12 electrically
connects the electrode 1 with a terminal of the power source 18. A
second terminal of the power supply 18 may be connected to a ground
electrode 20 via a cable 23 (See FIG. 1).
[0028] FIG. 3 shows an applicator 13b that may be used for the
applicator 13 in accordance with another embodiment of the
invention. The applicator 13b comprises an electrode 100 consisting
of a plurality of conducting pins 101 extending from a conducting
plate 102. The pins 101 are separated by electrical insulating
material 105. The applicator 13b is used similarly as the
applicator 13a to deliver electrical current to discrete volumes of
skin 4.
[0029] The pins 5 in the applicator 13a and the pins 101 in the
applicator 13b are provided with blunt tips 7 and 107,
respectively. This prevents the pins 5 and 101 from penetrating
into the skin when the electrode 13a or 13b is applied t the skin
surface. Thus, the applicators 13a and 13b provide simultaneous
non-invasive coagulation of skin regions 4.
[0030] FIG. 4 shows an applicator 13c that may be used for the
applicator 13 in accordance with another embodiment of the
invention. The applicator 13c is configured to be used for invasive
collagen remodeling. The applicator 13c includes an electrode 201
having a plurality of protruding conducting pins 205. The pins 205
have sharp tips 206 that are configured to penetrate through the
epidermis 202 into the dermis 203 when pressed on the skin as shown
in FIG. 4. The applicator 13c is used similarly to the applicators
13a and 13b so that the treatment of the skin occurs simultaneously
in a plurality of discrete skin volumes 204. However, unlike the
discrete volumes 4, which are located in the epidermis (see FIGS. 2
and 3), the volumes 204 are located below the surface in the dermis
203 (FIG. 4). This reduces skin redness that sometimes occurs when
the treated regions are in the epidermis. A maximal current density
is created at the tips of the pins 205. The sides of the protruding
elements may be coated with insulating material to avoid skin
heating around the pins 205 (not shown).
[0031] The present invention can be combined with other methods of
skin treatment including laser treatment. For example non-ablative
collagen remodeling by laser radiation may be combined with the
invasive RF heating of the skin dermis in accordance with the
invention.
[0032] The preferable parameters for non-invasive skin coagulation
in accordance with the invention are as follows: [0032] Electrode
size above 0.3 cm; [0033] Protruding element at contact with the
skin up to 0.5 mm [0034] Protruding element height about 1 mm.
[0035] Distance between protruding elements at least twice the
element diameter; [0036] Current density: over 1 A/cm.sup.2; [0037]
RF current pulse duration: not longer than 0.5 sec; [0038] The
optimal parameters for invasive skin coagulation:
[0033] Electrode size above 0.3 cm; [0040] Pin diameter at contact
with the skin not larger than 0.3 mm [0041] Pin protruding height
above 1 mm. [0042] Distance between pins at least 1 mm; [0043]
Current density above 0.1 A/cm.sup.2; [0044] RF current pulse
duration not longer than 0.5 sec.
* * * * *