U.S. patent application number 13/659296 was filed with the patent office on 2013-02-28 for method and device for tightening tissue using electromagnetic radiation.
This patent application is currently assigned to RELIANT TECHNOLOGIES, INC.. The applicant listed for this patent is RELIANT TECHNOLOGIES, INC.. Invention is credited to Kin F. Chan, Basil M. Hantash.
Application Number | 20130053931 13/659296 |
Document ID | / |
Family ID | 39710769 |
Filed Date | 2013-02-28 |
United States Patent
Application |
20130053931 |
Kind Code |
A1 |
Hantash; Basil M. ; et
al. |
February 28, 2013 |
METHOD AND DEVICE FOR TIGHTENING TISSUE USING ELECTROMAGNETIC
RADIATION
Abstract
Methods and devices for treatment of skin are disclosed. These
methods and devices use electromagnetic radiation to create
networks or patterns of treatment zones. The networks or patterns
of treatment zones comprise at least four treatment zones, at least
two of the treatment zones in the network or pattern are slanted at
angles in the skin, and the treatment zones extend at least as deep
as the dermal-epidermal junction of the skin. Producing
intersecting treatment zones and/or overlapping treatment patterns
can increase the effectiveness of the treatments. The devices
comprise a hand piece operably coupled to a delivery element,
wherein delivery of electromagnetic radiation through the device to
a portion of skin produces a network or pattern of treatment zones.
The use of these methods and devices results in tightening of the
skin and/or improvement in the cosmetic appearance of wrinkles in
the portion of skin treated.
Inventors: |
Hantash; Basil M.; (East
Palo Alto, CA) ; Chan; Kin F.; (San Jose,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
RELIANT TECHNOLOGIES, INC.; |
Hayward |
CA |
US |
|
|
Assignee: |
RELIANT TECHNOLOGIES, INC.
Hayward
CA
|
Family ID: |
39710769 |
Appl. No.: |
13/659296 |
Filed: |
October 24, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12035956 |
Feb 22, 2008 |
8323253 |
|
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13659296 |
|
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60891422 |
Feb 23, 2007 |
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Current U.S.
Class: |
607/100 |
Current CPC
Class: |
A61B 18/203 20130101;
A61B 2018/20359 20170501; A61B 2018/00005 20130101; A61B 2018/00452
20130101; A61B 2018/20355 20170501; A61B 2018/20351 20170501 |
Class at
Publication: |
607/100 |
International
Class: |
A61N 5/00 20060101
A61N005/00 |
Claims
1. A method for treating skin, the method comprising: delivering
electromagnetic radiation at an acute angle relative to a first
line substantially perpendicular to the surface of a portion of
skin; treating the portion of skin with the electromagnetic
radiation in a manner so as to create a network of treatment zones
in the portion of skin, wherein the network comprises at least four
treatment zones, at least two of the treatment zones in the network
are slanted at angles between a second line projected along a
length of each slanted treatment zone and the first line, the
treatment zones extend at least as deep as a
dermal-epidermal-junction of the portion of skin, at least one of
the treatment zones in the network intersects another treatment
zone at a point below an epidermal layer of the portion of skin,
and the treating results in tightening of the portion of skin.
2. The method of claim 1, wherein the network comprises at least
twenty treatment zones.
3. The method of claim 1, wherein the network comprises at least
fifty treatment zones.
4. The method of claim 1, wherein the network has a treatment zone
density of between about 50 treatment zones/cm.sup.2 and about 2000
treatment zones/cm.sup.2 in the portion of skin.
5. The method of claim 1, wherein the network is created by at
least two passes of a handpiece over the portion of skin during the
treating.
6. The method of claim 1, wherein the treatment zones extend from a
surface of the portion of skin through an epidermal layer and into
a dermal layer of the portion of skin.
7. The method of claim 1, wherein the treatment zones extend from a
lower epidermal layer of the portion of skin into a dermal layer of
the portion of skin, leaving at least a layer of stratum corneum
substantially intact.
8. The method of claim 1, wherein tissue within the treatment zones
is ablated.
9. The method of claim 1, wherein each of the treatment zones
intersects at least one other treatment zone in the network.
10. The method of claim 1, wherein the treatment zones intersect at
a point below the dermal-epidermal junction of the portion of
skin.
11. The method of claim 1, wherein each of the treatment zones has
a unique focal point.
12. The method of claim 1, wherein the angles are between about 10
degrees and about 85 degrees.
13. The method of claim 1, wherein the angles are
predetermined.
14. The method of claim 1, wherein the angles are randomly
generated during the treating.
15. The method of claim 1, wherein skin substantially
perpendicularly above the point at which the treatment zones
intersect is not treated.
16. The method of claim 1, wherein the treating improves the
cosmetic appearance of wrinkles in the portion of skin.
17. The method of claim 1, wherein the method further comprises
cooling of an epidermal layer of the portion of skin before, during
or immediately following the treating.
18. A device for treating skin, comprising: a handpiece operably
coupled to a delivery element, wherein the delivery element is
configured to deliver electromagnetic radiation at an acute angle
relative to a first line substantially perpendicular to the surface
of a portion of skin and the electromagnetic radiation produces a
network of at least four treatment zones, wherein at least two of
the treatment zones in the network are slanted at angles between a
second line projected along a length of each slanted treatment zone
and the first line, the treatment zones extend at least as deep as
a dermal-epidermal junction of the portion of skin, and at least
one of the treatment zones in the network intersects another
treatment zone in the network.
19. A device for treating skin, comprising: a handpiece operably
coupled to a delivery element, wherein the delivery element is
configured to deliver electromagnetic radiation at an acute angle
relative to a first line substantially perpendicular to the surface
of a portion of skin and the electromagnetic radiation produces a
pattern of at least four treatment zones, wherein at least two
treatment zones in the pattern are slanted at angles between a
second line projected along a length of each slanted treatment zone
and the first line, and the treatment zones extend at least as deep
as a dermal-epidermal junction of the portion of skin.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of application Ser. No.
12/035,956, filed Feb. 22, 2008, which claims the benefit of U.S.
Provisional Application No. 60/891,422, filed Feb. 23, 2007 under
35 U.S.C. 119(e). Each of these patent documents is hereby
incorporated by reference herein in its entirety.
BACKGROUND
[0002] The present invention relates generally to methods and
devices for providing cosmetic, medical or surgical treatments
using electromagnetic radiation, and in particular to methods and
devices for providing fractional treatments of tissue using
electromagnetic radiation in a manner so as to tighten the tissue,
particularly skin.
[0003] Electromagnetic radiation, including ultraviolet radiation,
visible light, infrared radiation, radar, and radio waves, has been
applied directly to tissue, particularly skin, for many purposes,
including for treatment of dermatological conditions, resurfacing,
and to combat the effects of aging. Electromagnetic radiation can
be coherent in nature, such as laser radiation, or non-coherent in
nature, such as flash lamp radiation. Coherent electromagnetic
radiation can be produced by lasers, including gas lasers, dye
lasers, metal-vapor lasers, and/or solid-state lasers. Depending on
the type of electromagnetic radiation (laser, flash lamp, radio
frequency, etc.), the mode of usage (continuous wave or pulsed),
and other parameters, such as the pulse width, the energy density
and the power, different types of treatments and effects can be
accomplished.
[0004] Electromagnetic radiation has been used to treat common
dermatological problems, including hypervascular lesions, pigmented
lesions, acne scars, rosacea, and hair removal. Electromagnetic
radiation has also been used in aesthetic surgery to achieve better
cosmetic appearances by resurfacing the skin and remodeling the
different layers of skin, improving the appearance of wrinkled or
aged skin. Generally, skin resurfacing is understood to be the
process by which the top layers of the skin are completely removed
using chemicals, mechanical abrasion or electromagnetic radiation
to promote the development of new, more youthful looking skin and
stimulate the generation and growth of new skin. For example,
pulsed CO.sub.2 laser skin resurfacing typically ablates the
existing tissue to a layer below the papillary dermis, which can
cause heat-induced coagulation to several hundred micrometers below
the original skin surface. Following resurfacing, the tissue is
regenerated and remodeled, producing skin with a better cosmetic
appearance (i.e., improving photodamage, the appearance of
wrinkles, acne scars, and other unwanted features).
[0005] A number of possible mechanisms may be responsible for the
improvement of the appearance of the skin following resurfacing.
Ablation and subsequent regeneration and remodeling of collagen
through heat-induced collagen contraction may be involved. For
example, in laser skin remodeling, the laser energy penetrates into
the deeper layers of the skin and is aimed at altering and
stimulating regeneration of the structure of extra-cellular matrix
materials, such as collagen, that contribute to the youthful
appearance of skin. Another possible mechanism which may lead to
improvement in the appearance of skin is tightening of the skin
through wound contraction which occurs as part of the normal wound
healing process. Some studies have concluded that heat-induced
collagen tightening is responsible for the long-lasting skin
tightening produced by CO.sub.2 laser skin resurfacing. (See, e.g.,
Fitzpatrick R E et al. (2000) Collagen Tightening induced by carbon
dioxide laser versus erbium:YAG laser, Lasers Surg Med,
27(5):395-403).
[0006] Generally, the desired effects on the skin are thought to be
accomplished by electromagnetic radiation-induced heating of the
tissue. Induced heating for specific temperature and heating time
combinations can result in thermal coagulation, cell necrosis,
hemostasis, melting, welding, ablation and/or gross alteration of
the extra-cellular matrix. When using electromagnetic radiation for
skin resurfacing and/or remodeling, an important objective has been
to provide uniform treatment across the desired treatment site.
With such treatments, particular care is exercised, either by the
physician alone or by combining the physician's judgment with
intelligence that is built into the dermatological system, to leave
no tissue untreated in the targeted region of the skin. Whether
using a broadly radiating pulsed beam of radiation or a focused
beam of radiation that produces a relatively smaller spot size, the
goal has been to expose the entire treatment area to the
electromagnetic radiation, in order to heat the entire volume of
tissue in the treatment area and bring about the desired change. It
has been widely reported that such broad area or bulk treatments
result in undesirable side effects such as intolerable pain,
prolonged erythema, swelling, occasional scarring, extended healing
times, and infection.
[0007] Various forms of electromagnetic radiation, including laser
radiation and radio frequency (RF) radiation, are increasingly
being used for skin rejuvenation, including tightening the skin,
particularly the skin of the facial area, to reduce the appearance
of wrinkles and combat the effects of aging. Radiation sources
frequently used for skin rejuvenation include CO.sub.2 lasers,
short pulsed Erbium:Ytrrium-Aluminum-Garnet (Er:YAG) lasers,
combined CO.sub.2/Er:YAG lasers, variable pulsed Er:YAG lasers,
ablative radiofrequency devices, non-ablative lasers, and intense
light sources. Of the commonly used treatments, resurfacing
treatments using CO.sub.2 lasers are generally considered to
provide the most effective treatment for wrinkles and photoaging,
as they produce the greatest degree of tightening of skin. (See,
e.g., Goldberg D J, (2003) Lasers for facial rejuvenation, Am J
Clin Dermatol 4(4):225-34). However, these bulk CO.sub.2 laser
treatments ablate large areas of the skin, cause dermal wounds,
produce significant thermal effects within the treated tissue, and
require long periods of time to heal-in many cases, up to a two
week period of second-degree burn wound management and months of
prolonged erythema.
[0008] Less aggressive treatments, such as lower energy or
non-ablative lasers, while still effective in rejuvenating skin,
typically produce fewer and less severe side effects and heal more
rapidly. However, these less aggressive treatments typically do not
produce as great of long-term improvements in tightening of skin
and reduction in the cosmetic appearance of wrinkles as bulk
CO.sub.2 laser treatments. An objective of non-ablative skin
rejuvenation is to induce a thermal wound repair response in the
papillary and upper reticular layers of the dermis (approximately
100-400 micrometers below the surface of the skin) while sparing at
least some cells at the junction between the dermal and epidermal
layers of the skin. One approach used to achieve this objective is
to spare the epidermal layer. To spare the epidermal layer, low
fluences (laser energy densities) can be used. Unfortunately, such
low levels are generally inadequate to promote the kinds of
stimulation that is required to produce the desired tightening of
the skin and reduction in the appearance of wrinkles. Thus,
nonablative approaches can result in minimal efficacy. In most
cases, minimal dermal matrix remodeling and minimal clinical
responses (e.g., wrinkle reduction, retexturing, dyschromia
reduction, and telangiectasia removal) are achieved by these
procedures (See, e.g., Nelson et al, (2002) What is Nonablative
Photorejuvenation of Human Skin, Seminars in Cutaneous Medicine and
Surgery, 21:(4)238-250, 2002; Leffell D (2002) Clinical Efficacy of
Devices of Nonablative Photorejuvenation, Arch. Dermatol.
138:1503-1508). Therefore, there is an unmet need for methods and
devices which provide electromagnetic radiation treatments which
spare the epidermal layer of the skin, but achieve enough
stimulation of dermal matrix remodeling to be clinically effective
in rejuvenating skin, tightening skin and treating wrinkles.
[0009] Various devices and approaches have been proposed to reduce
the extent and duration of the side effects produced by treating
tissue with electromagnetic radiation. One approach to minimize the
effects of bulk heating of the skin is to cool the skin before,
during or immediately following treatment, in an effort to reduce
the level of thermal damage to the epithelium. While methods and
systems such as these can reduce the damage to the skin during
treatment, cooling systems pose practical limitations because of
their added complexity. Another approach to sparing the epithelium
includes systems that deliver electromagnetic radiation over a
relatively large tissue surface area with the radiation focused in
the dermis. Treatment methods such as these are designed to cover
the target tissue in the plane of the skin completely with
overlapping treatment zones so that no tissue in the treated
portion of skin is left unexposed to electromagnetic radiation.
However, by their nature, bulk treatment methods lead to an
increase in clinical side effects and to an increase in healing
time, and force physicians to lower the treatment intensity,
resulting in less effective treatments.
[0010] When electromagnetic radiation at an effective treatment
level is applied to tissue or skin, a burn or an acute wound is
usually created. For acute wounds, the skin heals by three distinct
`response to injury` waves. The initial inflammatory phase has a
duration lasting minutes to days, and seamlessly transitions into
the cell proliferative phase, lasting 1 to 14 days. This cell
proliferative phase is slowly replaced by the dermal maturation
phase that lasts from weeks to months (See, e.g., Clark R (1999)
Mechanisms of cutaneous wound repair. In: Fitzpatrick T B, ed.
Dermatology in General Medicine, 5th Ed., McGraw-Hill, New York,
N.Y. pp. 327-41).
[0011] In general, a direct correlation exists between the size of
the injury and the time required for complete repair. However, the
inflammatory phase is a function of cellular necrosis, particularly
epidermal (i.e., keratinocyte) necrosis, and a direct correlation
exists between cellular necrosis and the inflammatory phase.
Increased cellular necrosis, particularly epidermal necrosis,
prolongs the inflammatory phase. Prolonging and/or accentuating the
inflammatory phase may be undesirable from a clinical perspective
due to increased pain and extended wound repair, and may retard
subsequent phases of wound repair. The cause(s) of this prolonged
inflammatory phase are not well understood. However, injuries
caused by electromagnetic radiation are associated with early and
high levels of dermal wound repair (e.g., angiogenesis, fibroblast
proliferation and matrix metalloproteinase (MMP) expression) but
delayed epidermal resurfacing (See, e.g., Schaffer et al, (1997)
Comparisons of Wound Healing Among Excisional, Laser Created and
Standard Thermal Burn in Porcine Wounds of Equal Depth, Wound Rep
Reg 5(1):51-61). Unfortunately, most of the skin resurfacing
efforts and selective photothermolysis treatments that affect large
contiguous areas of chromophores result in a prolonged, exaggerated
inflammatory phase leading to undesirable consequences such as
delayed wound repair. The prolonged inflammatory phase also leads
to the pain experienced by most patients undergoing skin
resurfacing procedures. Undesirable extended inflammatory response
phase can be attributed to the bulk heating of the skin with little
or no healthy tissue, particularly keratinocytes, left behind in
the area where the skin was exposed to the electromagnetic
radiation. Particularly when uniform treatment is desired and the
entire target tissue volume is exposed to electromagnetic radiation
without sparing any tissue within the target volume, pain,
swelling, fluid loss, prolonged reepitheliazation and other side
effects of dermatological laser treatments are commonly experienced
by patients.
[0012] Increasingly, conventional bulk skin treatment methods are
being replaced by various fractional treatment methods, as the use
of fractional treatment methods has been found to produce fewer and
less severe side effects than conventional bulk treatment methods,
including reduced damage to the epidermal layers of the skin.
Fractional treatment methods involve the generation of a large
number of treatment zones within a region of tissue. The
electromagnetic radiation impacts directly on only the relatively
small treatment zones, instead of impacting directly on the entire
region of tissue undergoing treatment, as it does in conventional
bulk treatments. Thus, a region of skin treated using a fractional
electromagnetic radiation treatment method is composed of a number
of treatment zones where the tissue has been altered by the
radiation, contained within a larger volume of tissue that has not
been altered by the radiation. Fractional treatment methods make it
possible to leave substantial volumes of tissue unaltered and/or
viable within a treatment region.
[0013] Various fractional treatment methods have been used for
treating both existing medical (e.g., dermatological) disease
conditions and for improving the appearance of tissue (e.g., skin)
by intentionally generating regions of thermally altered tissue
surrounded by unaltered tissue. Fractional treatment methods
generally offer numerous advantages over existing approaches in
terms of safety and efficacy. Fractional treatment methods can
reduce the undesirable side effects of pain, erythema, swelling,
fluid loss, prolonged reepithelialization, infection, and
blistering generally associated with laser skin resurfacing. By
sparing healthy tissue around the thermally altered tissue,
fractional treatment methods can increase the rate of recovery of
the treatment zones by stimulating skin remodeling and wound repair
mechanisms. Fractional treatment methods can also reduce or
eliminate the side effects of repeated electromagnetic radiation
treatments to tissue by controlling the extent of tissue necrosis
due to exposure to electromagnetic radiation.
[0014] Among other approaches, U.S. Pat. No. 6,997,923 describes
methods of treating a volume of a patient's skin by irradiating
portions of the volume. The patent describes a method for
performing a treatment on a volume located at area and depth
coordinates of a patient's skin, the method involving providing a
radiation source and applying radiation from the source to an
optical system which concentrates the radiation to at least one
depth within the area coordinates of the volume, the at least one
depth and the selected areas defining three-dimensional treatment
portions of the volume within untreated portions of the volume. The
method is described as producing irradiated portions of tissue or
treatment regions, where each irradiated portion is surrounded by a
non-irradiated portion, and each treatment region is separated from
other treatment regions by untreated tissue.
[0015] U.S. patent application Ser. No. 10/888,356 (US Patent
Application Publication Number US 2005/049582) describes methods
and apparatus for generating isolated, non-contiguous tissue
volumes having treatment zones comprising necrotic tissue,
surrounded by zones of viable tissue that are capable of promoting
healing of the target tissue. Specifically, the application
describes creating a plurality of microscopic treatment zones in a
predetermined treatment pattern, wherein a subset of the plurality
of discrete microscopic treatment zones includes discrete
microscopic treatment zones comprising necrotic tissue volumes
having an aspect ratio of at least about 1:2.
[0016] U.S. patent application Ser. No. 11/097,825 (US Patent
Application Publication Number US 2005/0222555) describes apparatus
and methods for treating skin by providing a skin damaging means
and applying the skin damaging means to create a plurality of
micro-lines of damaged tissue in a region of skin separated by
regions of undamaged skin tissue, wherein the micro-lines are
substantially parallel and traverse at least part of said region of
skin being treated. The application defines `micro-lines` as narrow
regions of damaged dermal tissue, generally less than 1 mm in
width, that extend from the surface of the skin into the epidermis
and, optionally, through the epidermis and into the dermal layer.
The micro-lines are long in one direction along the surface of the
skin, generally at least four to five times as long as the width of
the micro-lines, and may traverse part or all of the region of skin
being treated.
[0017] U.S. patent application Ser. No. 11/098,036 (US Patent
Application Publication Number US 2006/0004347) describes devices,
systems and methods of treatment of tissue with electromagnetic
radiation (EMR) to produce lattices of EMR-treated islets in the
tissue. The islets are described as being separated from each other
by non-treated tissue (or differently- or less-treated tissue), and
numerous advantages are attributed to the production of lattices of
EMR-treated islets in the tissue rather than large, continuous
regions of EMR-treated tissue.
[0018] These treatment methods can be suitable for treating skin to
achieve a better cosmetic surface by resurfacing the skin and
remodeling the layers of skin to improve the appearance of wrinkled
or aged skin while avoiding extensive damage to the epithelial
layer of the skin. Using these treatment methods can produce small
to moderate increases in tightening of the skin and the cosmetic
appearance of wrinkles due to shrinkage of collagen fibrils
subjected to elevated temperature or coagulation of localized areas
in the dermis and hypodermis. However, the level of improvement in
skin tightening and the appearance of wrinkles achieved using these
treatment methods appears to be less than the level of improvement
achieved using bulk ablative treatments, such as conventional
pulsed CO.sub.2 laser skin resurfacing. A need remains in the art
for methods of treatment and devices which provide the benefits of
fractional electromagnetic radiation treatment methods while
achieving significant increases in skin tightening and the
appearance of wrinkles more comparable to those produced by bulk
electromagnetic radiation treatment methods and devices.
BRIEF SUMMARY
[0019] Methods and devices are disclosed for treating skin by using
electromagnetic radiation to create networks or patterns of
treatment zones in a portion of skin. The devices comprise a
handpiece operably coupled to a delivery element, wherein delivery
of electromagnetic radiation through the device to a portion of
skin produces a network or pattern of treatment zones. The networks
or patterns of treatment zones contain at least four treatment
zones, of which at least two of the treatment zones are slanted at
angles in the portion of skin, and the treatment zones extend at
least as deep as the dermal-epidermal junction of the portion of
skin. Producing intersecting treatment zones and/or overlapping
treatment patterns can increase the effectiveness of the
treatments. The use of these methods and devices results in
tightening of the skin and/or improvement in the cosmetic
appearance of wrinkles in the portion of skin treated. These
methods and devices can be used to provide cosmetic, medical and/or
surgical treatments to tissue.
[0020] In one example, the method for treating skin comprises
treating a portion of skin with electromagnetic radiation in a
manner so as to create a network of treatment zones in the portion
of skin, wherein the network comprises at least four treatment
zones, at least two of the treatment zones in the network are
slanted at angles in the portion of skin, the treatment zones
extend at least as deep as a dermal-epidermal-junction of the
portion of skin, at least one of the treatment zones in the network
intersects another treatment zone in the network, the treatment
zones intersect at a point below an epidermal layer of the portion
of skin, and the treating results in tightening of the portion of
skin. In another example, the treating results in an improvement in
the cosmetic appearance of wrinkles in the treated portion of skin.
In another example, the treatment zones intersect at a point below
the dermal-epidermal junction of the portion of skin. In yet
another example, the skin substantially perpendicularly above the
point at which the treatment zones intersect is not treated.
[0021] In another example, the method for treating skin comprises
treating a portion of skin with electromagnetic radiation in a
manner so as to produce a pattern of treatment zones in the portion
of skin, wherein the pattern comprises at least four treatment
zones, at least two of the treatment zones in the pattern are
slanted at angles in the portion of skin, the treatment zones
extend at least as deep as a dermal-epidermal-junction of the
portion of skin, and the treating results in tightening of the
portion of skin. In another example, the treating results in an
improvement in the cosmetic appearance of wrinkles in the treated
portion of the skin. In another example, a first treatment pattern
is at least partially overlapped with a second treatment pattern.
In another example, at least partially overlapping the first and
second treatment patterns causes at least one treatment zone in the
first pattern to intersect a treatment zone in the second pattern.
In yet another example, at least two of the treatment zones in the
pattern are slanted at angles such that lines projected along the
length of each treatment zone intersect at substantially a single
point below a surface of the portion of skin, wherein the treatment
zones do not extend as deep as the point and do not intersect.
[0022] In one example, the device for treating skin comprises a
hand piece operably coupled to a delivery element, wherein delivery
of electromagnetic radiation through the device to a portion of
skin produces a network of at least four treatment zones, at least
two of the treatment zones are slanted at angles in the portion of
skin, the treatment zones extend at least as deep as the
dermal-epidermal junction of the portion of skin, and at least one
of the treatment zones in the network intersects another treatment
zone in the network. In another example, the treatment zones
intersect at a point below the epidermal layer of the skin. In
another example, the treatment zones intersect at a point below the
dermal-epidermal junction of the portion of skin. In yet another
example, the skin substantially perpendicularly above the point at
which the treatment zones intersect is not treated.
[0023] In another example, the device comprises a hand piece
operably coupled to a delivery element, wherein delivery of
electromagnetic radiation through the device to a portion of skin
produces a pattern of at least four treatment zones, at least two
of the treatment zones are slanted at angles in the portion of
skin, and the treatment zones extend at least as deep as a
dermal-epidermal junction of the portion of skin. In another
example, all the treatment zones in the pattern are slanted at
angles in the portion of skin. In yet another example, the slanted
treatment zones in the pattern are slanted at angles such that
lines projected along the length of each slanted treatment zone
intersect at substantially a single point below an epidermal layer
of the portion of skin, wherein the treatment zones in the pattern
do not extend as deep as the point and do not intersect.
[0024] Other aspects of the invention include methods corresponding
to the devices described above.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0025] The invention has other advantages and features which will
be more readily apparent from the following detailed description of
the invention and the appended claims, when taken in conjunction
with the accompanying drawings, in which:
[0026] FIG. 1 is a cross-sectional drawing illustrating the layers
of the skin.
[0027] FIG. 2 consists of two drawings, a top-view (FIG. 2A) and a
cross-sectional view (FIG. 2B) illustrating a series of
intersecting slanted treatment zones which form a treatment
network.
[0028] FIG. 3 consists of two cross-sectional drawings illustrating
a treatment network of intersecting slanted treatment zones (FIG.
3A) and a treatment network of intersecting slanted and
substantially perpendicular treatment zones (FIG. 3B).
[0029] FIG. 4 consists of two drawings, a top-view drawing (FIG.
4A) and a perspective drawing (FIG. 4B) showing a treatment pattern
created using four slanted beams of electromagnetic radiation which
impact a portion of skin, forming four slanted treatment zones in
the epidermal and dermal layers of the skin.
[0030] FIG. 5 consists of two drawings, a perspective view (FIG.
5A) and a cross-sectional view (FIG. 5B) showing a treatment
pattern of five beams of electromagnetic radiation impacting a
portion of skin.
[0031] FIG. 6 consists of two drawings, a perspective view (FIG.
6A) and a cross-sectional view (FIG. 6B) showing three treatment
patterns, each containing five beams of electromagnetic radiation,
impacting a portion of skin. The three treatment patterns in FIG. 6
are not overlapped.
[0032] FIG. 7 is composed of two drawings, a perspective view (FIG.
7A) and a cross-sectional view (FIG. 7B) showing three treatment
patterns, each containing five beams of electromagnetic radiation,
impacting a portion of skin. The three treatment patterns in FIG. 7
are partially overlapped, producing intersecting treatment
zones.
[0033] FIG. 8 is a cross-sectional drawing illustrating a device
for treating skin which can be used to produce slanted,
intersecting treatment zones in a portion of skin.
[0034] FIG. 9 is a cross-sectional drawing illustrating a device
for treating skin which uses a galvanometer scanner and a starburst
scanner to deflect a beam of electromagnetic radiation in two
dimensions, creating a network and/or pattern of treatment zones in
a portion of skin.
DETAILED DESCRIPTION
[0035] As used in the specification and the appended claims, the
singular forms "a," "an" and "the" include plural referents unless
the context clearly dictates otherwise.
[0036] "Tissue" refers to an aggregate of cells that perform
specific functions, including but not limited to muscle, organs,
and the skin, including the epidermis, dermis and subcutis. The
cells of a tissue may or may not form a layer.
[0037] "Treatment zone" refers to a region of tissue within a
larger volume of tissue which receives an effective amount of
electromagnetic radiation. Thus, when a region of tissue is treated
with electromagnetic radiation in a fractional manner, the region
of tissue will contain a plurality of treatment zones to which
electromagnetic radiation was directed, surrounded by regions to
which electromagnetic radiation was not directed. Treatment zones
can be created independently or more than one treatment zone can be
created simultaneously or effectively simultaneously. A number of
treatment zones can be created in a network or pattern, and the
network or pattern can be repeated and/or overlapped within a
portion of skin. Depending upon the treatment method and/or method
of delivering the electromagnetic radiation used, a treatment zone
can be comprised of tissue that has been ablated, necrosed,
coagulated, melted, welded, and/or had its extra-cellular matrix
grossly altered in some manner. Also depending upon the treatment
method and/or method of delivering the electromagnetic radiation
used, treatment zones may or may not intersect other treatment
zones (i.e., may or may not be separate or discrete).
[0038] "Tightening" as used herein is synonymous with contracting,
shrinking, constricting and pulling together tissue, either in a
horizontal, vertical or angular direction.
[0039] The drawing in FIG. 1 illustrates the basic structure of the
skin, the body's outer covering. The skin is composed of three
principal layers, the epidermis (100), dermis (110) and subcutis
(120). The epidermis comprises the upper or outer layers of the
skin, is nonvascular, and varies in thickness over different parts
of the body. The epidermis itself is composed of several different
layers, specifically the stratum corneum (101), stratum lucidum
(102), stratum granulosum (103), stratum spinosum (104), and
stratum basale (105) layers.
[0040] Skin is a multilayered heterogenous tissue composed of
superimposed layers that are intimately connected but very distinct
in their nature, structure and properties. The top layer is the
epidermis, which is between about 0.06 mm and about 1.0 mm thick
and is composed of five distinct layers: the stratum corneum (101),
the stratum lucidum (102), the stratum granulosum (103), the
stratum spinosum (104), and the stratum basale (105). The epidermis
is connected to the lower layer, the dermis, which is between about
1 mm and about 4 mm thick and is composed primarily of cells and
extra-cellular matrix. The dermis can be further subdivided into
the papillary dermis and reticular dermis layers. (See, e.g.,
Reihsner R et al. (1995) Two-dimensional elastic properties of
human skin in terms of an incremental model at the in vivo
configuration, Med. Eng. Phys., 17(4):304-313; Silver F et al.
(2003) Mechanobiology of force transduction in dermal tissue, Skin
Research and Technology 9:3-23.)
[0041] The uppermost or outermost layer of the skin is the stratum
corneum (101), also known as the "horny layer" of the skin. The
cells within the stratum corneum are flat and scale-like in shape
and hydrophobic in nature. These dead, non-nucleated cells,
composed mainly of the protein keratin, are arranged in
overlapping, often peeling layers with naturally interspersed
pores.
[0042] Below the stratum corneum (101) is the stratum lucidum
(102), a homogeneous translucent band, much thinner than the layers
above and below it. Below the stratum lucidum (102) layer of the
epidermis is the stratum granulosum (103), composed of two or three
rows of flat cells composed mainly of keratohyalin, which is
transformed into keratin in more superficial layers. Below the
stratum granulosum (103) is the stratum spinosum (104), composed of
several layers of polygonal cells known as "prickle cells". The
number of layers of cells in the stratum granulosum varies over
different regions of the body. Below the stratum spinosum (104)
layer is the stratum basale (105) layer, also known as the stratum
germinativum, the deepest layer of the epidermis. The stratum
basale is composed of columnar cells which are continually dividing
to produce new skin cells. It is the cells in the stratum basale
that produce melanin. Over time, the cells produced in the stratum
basale move upward and away from the blood supply, and their cell
contents and shapes change, forming the different layers of the
epidermis. The dermal-epidermal junction is the region of the skin
in which the bottom layer of the epidermis (the stratum basale
(105)) and the top layer of the dermis (the papillary dermis (111))
join.
[0043] The dermis (110) is the inner layer of the skin containing
blood capillaries, blood vessels, lymph vessels, hair follicles,
and various glands, including eccrine sweat glands and sebaceous
glands. The dermis is composed of felted connective tissue
containing elastin, collagen and fat. The dermis is divided into
the upper, papillary layer (111) and the lower, reticular layer
(112). The papillary layer (111) of the dermis typically contains a
large number of dermal papillae which rise perpendicularly from its
surface. The papillary layer (111) of the dermis also contains
blood capillaries which carry nutrients to, and remove waste from,
the dividing cells in the stratum basale (105). The reticular layer
(112) of the dermis typically contains veins, arteries, sebaceous
glands, arrector pili muscles, sensory nerve fibers, hair
follicles, hair roots, pacinian corpuscles, hair root plexus, and
eccrine sweat glands.
[0044] At the base of the dermis lies the subcutis (120), also
known as the hypodermis or superficial fascia, which separates the
dermis from the underlying muscle and is composed primarily of
adipose tissue (121).
[0045] The mechanical properties of skin reflect the passive
behavior of the elastin and collagen fibers in the dermis, as well
as an active component reflecting keratinocyte-keratinocyte,
fibroblast-fibroblast, and fibroblast-extracellular matrix
interactions. While collagen is the main source of strength and
stiffness of skin, elastin fibers forming a scattered delicate
network between the collagen fibers are thought to be primarily
responsible for the recoiling mechanism after a stress or
deformation has been applied. Aging produces major changes in
skin's mechanical properties. These changes are thought to be due
to increased crosslinking of collagen fibers, the degradation of
the elastin network, and age-dependent changes in the ground
substance which alter the viscoelastic properties. (See, e.g.,
Reihsner R et al (1995); Silver F et al. (2003)).
[0046] A state of tension exists naturally in the skin. For
example, wounded skin will gape, becoming elliptical instead of
round. A number of researchers have identified and characterized
different cleavage or tension lines in the skin (e.g., Langer's
cleavage lines, Kraissl's lines, Borges' relaxed skin tension lines
(RSTL), etc.) which can be followed when making surgical incisions
to try to minimize the appearance of scars. Relaxed skin tension
lines are usually perpendicular to the underlying muscle, and do
not necessarily correlate with wrinkle lines. Borges' lines are
considered by some surgeons to be the best guide for elective
incisions on the face, while Kraissl's lines are considered the
best guide for the rest of the body. On the face, Borges' RSTL
follow furrows formed when the skin is relaxed. They are not
visible features of the skin, as are wrinkles. Borges' lines are
derived from the furrows produced by pinching the skin; fewer and
higher furrows are produced when pinching skin parallel to the
lines. Borges' lines are almost perpendicular to Langer's lines in
the areas of the scalp, forehead, glabella, mid-cheek, and lateral
eye. (See, e.g., Wilhelmi B (1999) Langer's Lines: To Use or Not to
Use, Plastic and Reconstructive Surgery 104(1):208-214)
[0047] In the skin, external forces are transmitted through the
epidermis to the dermis and the underlying subcutaneous tissues,
while internal forces are transmitted through the dermis to the
epidermis. Internal forces in the skin exist as passive tension in
the collagen fibrils of the dermis running almost parallel to the
Langer's lines and are augmented by active cytoskeletal tension.
Tension in the epidemis has been speculated to lead to stretching
of the basal epithelial cell junctions, resulting in tension at the
dermal-epidermal junction. The active cellular tension also acts
approximately along the Langer's lines and is produced by
fibroblast contraction of collagen fibrils in the extra-cellular
matrix. In the absence of external forces, the internal tension
acting on the collagen fibrils of the dermis cause tension to occur
at keratinocyte-keratinocyte cell junctions. External forces
applied to the skin surface at the air-epidermis interface also
increase the tension at keratinocyte-keratinocyte cell junctions as
well as change the state of stress in the dermis. Transmission of
external forces through the epidermis to the dermis occurs through
a number of possible mechanisms, including:
keratinocyte-keratinocyte interactions in the epidermis,
keratinocyte-extra-cellular matrix interactions at the
dermal-epidermal junction, macromolecular-macromolecular
interactions in the dermis, and fibroblast-fibroblast interactions
in the dermis. It has been noted that the mechanical continuity of
the dermal-epidermal junction, as well as between the
keratinocytes, is key to normal transfer of internal and external
mechanical forces between the epidermis and dermis. It has also
been noted that the internal forces in the dermis are larger than
those in the epidermis, and that the epidermis can be stretched due
to tension transmitted from the underlying dermis (See, e.g.,
Silver F et al. (2003)).
[0048] As previously discussed, electromagnetic radiation is
frequently used to treat skin so as to tighten the skin and/or
reduce the cosmetic appearance of wrinkles. While conventional bulk
treatment methods and devices have been used to ablate or coagulate
tissue as deep as the dermis, the complete ablation or coagulation
of skin in the treated region has made it impossible to create a
treatment at an angle in the skin, or assess the impact of
treatment angle or treatment depth on the effectiveness of the
treatment. However, the advent of fractional treatment methods and
devices has let to the ability to control both the angle of
treatment zones in the skin and their depth. The advent of
fractional treatment methods and devices also make it possible to
create networks or patterns of treatment zones, and to orient these
networks or patterns in particular directions based on skin
features such as Langer's lines, Borges' lines, Kraissl's lines,
resting skin tension lines, wrinkles, etc.
[0049] A primary aspect of methods and devices described herein is
the fractional nature of the treatments, which involves the sparing
of volumes of tissue within a larger tissue treatment area. By
leaving healthy tissue between and around the treatment zones, a
number of beneficial effects are produced. If the treatment zones,
networks and/or patterns are appropriately spaced and/or epidermal
injury is limited, the viable tissue bordering the treatment zones
will be subjected to less inflammation from the products of cell
death, thereby favoring cell survival over apoptosis. These areas
will be better able to mount reepithelialization and
fibro-proliferative and subsequent remodeling phases of wound
repair. One important reason for this effect is that the treatment
zones and the bordering spared tissue contain subpopulations of
stem cells responsible for repopulating the epidermis (See, e.g.,
Watt F (2002) The Stem Cell Compartment in Human Interfollicular
Epidermis, J. Derm. Sci., 28:173-180). In humans, stem cells reside
in two locations in the skin: in focal clusters in the stratum
basale, and in the follicular bulge area surrounding hair shafts.
The stratum basale layer of the epidermis typically contains a low
population of these stem cells interspersed with large numbers of
transit-amplifying (TA) cells that are directly derived from stem
cells. Interfollicular epidermal stem cells tend to cluster at the
bases of rete ridges in acral areas and at the tips of dermal
papillae in non-acral skin. The follicular stem cell compartment
has been shown to possess the ability to re-populate the
interfollicular epidermal surfaces when required under certain
conditions. Such conditions include severe burns, large
split-thickness epidermal injuries, and cosmetic surgical
procedures (e.g., ablative laser resurfacing, chemical peels,
dermabrasion, keratotomy, etc.) that denude the epidermal layer,
leaving no epidermal stem cell populations. It is well known that
CO.sub.2 resurfacing results in prolonged reepithelialization when
compared to steel scalpel or electrosurgical scalpel incisions,
even though laser wounds exhibit accelerated dermal healing (See,
e.g., Schaffer et al., (1997) Comparisons of Wound Healing Among
Excisional, Laser Created and Standard Thermal Burn in Porcine
Wounds of Equal Depth, Wound Rep Reg 5(1):51-61). Reepithelization
to repair such defects is delayed under these circumstances,
because healing must occur from remaining follicular stem cell
populations within the de-epidermized wound and from epithelial
stem cells at the margins of the defect. If the wound is full
thickness, extending down to the level of the pilosebaceous unit,
then healing is delayed even further because epidermal healing
occurs only from the margins.
[0050] By creating isolated, non-contiguous (i.e., discrete)
treatment zones having coagulated and/or necrotic tissue surrounded
by zones of viable (i.e., heat altered but viable tissue and/or
untreated, un-altered healthy tissue) tissue that are capable of
promoting healing, fractional treatment methods induces multiple
sites of tissue regeneration. Following fractional treatment, a
treated portion of tissue is typically composed of thousands of
treatment zones that comprise "nodes" of wound repair. The healing
mechanisms (e.g., stem cells and TA cells) of each node can be
expected to expand beyond the volume of the node to merge with
neighboring nodes, replacing photo-aged tissue components (e.g.,
solar elastosis, microvascular ectasia, pigment incontinence,
epidermal atrophy, and atypia).
[0051] Fractional electromagnetic radiation treatment methods do
not treat the entire volume of tissue in a region undergoing
treatment. Not treating the entire volume of the tissue with
electromagnetic radiation, but instead treating only a fraction of
the tissue permits the retention of viable tissue between treatment
zones. In some cases, electromagnetic radiation treatment
parameters can be chosen which produce fractional treatments that
spare the outermost layers of the epidermis, such as, for example,
the stratum corneum, from significant damage. Such sparing of the
stratum corneum promotes healing by maintaining the structural
integrity and protective character of the stratum corneum.
Fractional treatments are fundamentally different from bulk
techniques because the areas of epidermal tissue that remain
untreated between treatment zones contain both epidermal stem cells
and TA cell populations. Thus, re-epithelization of treatment zones
proceeds rapidly with few or none of the side effects (i.e., pain,
persistent erythema, edema, fluid drainage, etc.) observed after
bulk resurfacing procedures. By using small treatment zone
cross-sections (e.g., for circular cross sections, less than about
500 micrometers in diameter, less than about 250 micrometers in
diameter, or less than about 100 micrometers in diameter),
significant numbers of stem cells and TA cells are relatively close
to the center of the treatment zone throughout the depth of the
treatment zone. This further speeds the healing response, such that
substantially complete (e.g., greater than about 75% complete)
re-epetheliazation typically occurs in less than about 36 hours
post-treatment for treatment zones with cross-section widths in the
range of less than about 250 micrometers. For treatment zones with
cross-sectional widths of less than about 100 micrometers,
substantially complete re-epetheliazation occurs less than about 24
hours post-treatment. Re-epetheliazation typically occurs at a rate
corresponding to the cross-sectional width of the treatment zone.
As a further example, if the spacing between fractional beam
treatment zones creates an average density (i.e., number of
treatment zones per unit surface area of the target treatment area)
of 500 treatment zones/cm.sup.2, there are ample epidermal stem
cells that remain for interfollicular resurfacing of the treatment
zone. In addition, after many types of fractional treatments with
electromagnetic radiation, the follicular bulge stem cell
population remains intact, so they may participate in wound healing
and resurfacing, as needed. The density of treatment can be
described using a fill factor (i.e., surface area receiving
radiation divided by total surface area of the target treatment
area), wherein a typical fill factor can be between about 0.05 and
about 0.95, or between about 0.1 and about 0.5. The density of
treatment can alternately be described using density (i.e., the
number of treatment zones produced per surface area treated),
wherein a typical treatment zone (TZ) density can be between about
50 TZ/cm.sup.2 and about 6000 TZ/cm.sup.2 or between about 200
TZ/cm.sup.2 and about 2000 TZ/cm.sup.2.
[0052] The methods of treatment and devices described herein
provide the benefits of fractional electromagnetic radiation
treatment methods while also producing significant levels of skin
tightening and/or improvement in the appearance of wrinkles. These
methods and devices can be used for cosmetic as well as
non-cosmetic purposes. These methods of treatment and devices can
be used on other tissues in addition to skin. These treatment
methods and devices, instead of creating a multiplicity of
isolated, non-contiguous, parallel treatment zones substantially
perpendicular to the surface of the skin, create a multiplicity of
treatment zones, a proportion of which are slanted at angles in the
portion of skin.
[0053] Networks or patterns of at least four treatment zones,
wherein the networks or patterns contain at least two slanted
treatment zones can be produced. In some cases, between about 0.5%
and about 100% of the treatment zones in the network or pattern are
slanted. In other cases, between about 25% and about 90% of the
treatment zones in the network or pattern are slanted. In other
cases, between about 50% and about 85% of the treatment zones in
the network or pattern are slanted. In some cases, the networks of
treatment zones can contain intersecting treatment zones. In some
cases, between about 0.5% and about 100% of the treatment zones in
the network or pattern intersect at least one other treatment zone
in the network or pattern. In other cases, between about 25% and
about 90% of the treatment zones in the network or pattern
intersect at least one other treatment zone in the network or
pattern. In other cases, between about 50% and about 85% of the
treatment zones in the network or pattern intersect at least one
other treatment zone in the network or pattern. In some cases, the
patterns of treatment zones can be at least partially overlapped,
which can produce intersecting treatment zones. In some cases, the
patterns are overlapped between about 0.5% and about 95%. In other
cases, the patterns are overlapped between about 25% and about 90%.
In other cases, the patterns are overlapped between about 50% and
about 85%.
[0054] The treatment zones, both those substantially perpendicular
to the surface of the skin and those slanted at angles in the skin,
penetrate at least as deep as the dermal-epidermal junction of the
portion skin. Methods of treatment and devices which produce these
networks or patterns containing slanted treatment zones can be used
to tighten skin and/or improve the cosmetic appearance of wrinkles
in the treated portion of skin. Producing networks of intersecting
treatment zones increases the treatment effects, as does producing
patterns of at least partially overlapping, and, in some cases,
intersecting, treatment zones.
[0055] Use of the treatment methods and devices described herein
results in the creation of a multiplicity of treatment zones
containing coagulated and/or necrosed tissue within a portion of
skin. Tension in the coagulated and/or necrosed tissue shrinks the
tissue, thereby tightening the skin. The wound-healing response,
which is enhanced by adjacent viable tissue surrounding the
treatment zones, causes replacement of the coagulated and/or
necrosed tissue with new viable tissue, further tightening the
tissue and enhancing skin elasticity. Creating treatment zones
which are slanted at angles in the portion of skin can increase the
shrinkage of the tissue, producing increased levels of skin
tightening. It can also create an anisotropic shrinkage of the
tissue as a whole. Creating networks or patterns containing slanted
treatment zones and/or creating intersecting treatment zones can
further increase the shrinking of the tissue, again increasing
tightening of the skin and reducing the appearance of wrinkles.
[0056] Depending upon the treatment parameters used, the treatment
can ablate, necrose, coagulate, melt, weld, and/or grossly alter
the extra-cellular matrix of the tissue within the treatment zones.
Sufficiently raising the temperature of collagen in the treatment
zones can result in dramatic shrinkage or shortening of the
collagen fibers, creating a region of contractile tissue within
each of the treatment zones. In cases where the treatment results
in ablation within the treatment zone, the contractile tissue
rapidly shrinks the ablated void. In cases where the treatment
results in coagulation and/or necrosis, the contractile tissue
creates an increase in skin tension, resulting in a prompt
reduction of overall skin laxity and the appearance of wrinkles.
Upon collagen shrinkage due to coagulation, the dermal tissue is
pulled inward, effectively tightening the dermal tissue. This
tightening due to collagen shrinkage pulls taut any overlying
laxity through a stretching of the epidermis and stratum corneum.
Treatment zones created substantially perpendicular to the skin
surface pull the dermal tissue up in the vertical direction, from
top to bottom. Treatment zones which are slanted at angles within
the skin, however, pull the dermal tissue up and sideways, adding
horizontal or side-to-side tension to the vertical tension, which
increases the skin tightening effects. The skin tightening effect
of collagen shrinkage is primarily due to the connection of the
basement membrane region of the epidermis to the collagen and
elastin extra-cellular matrix, which provides a link between the
epidermis and the dermis. Slanting the treatment zones at angles
within the skin increases the surface area over which this link is
created, and increases the side-to-side tension in the tissue. One
theory for the high levels of skin tightening produced by
conventional bulk CO.sub.2 laser skin treatments is that these
treatments have a significant effect on a large portion of dermal
tissue. Producing slanting treatment zones increases the amount of
dermal tissue impacted by the treatment while sparing the epidermal
layers of the skin from excessive damage. Intersecting the slanted
treatment zones below the epidermis (i.e., at or below the
dermal-epidermal junction) produces a larger region of dermis that
is linked to a given region of epidermis, further increasing skin
tightening Producing slanting treatment zones which intersect below
the dermal-epidermal junction, or avoiding treatment of the skin
perpendicularly above a point of intersection, spares the epidermis
from receiving the most damaging treatments (i.e., being treated
two times at the same spot). Sparing the epidermis while more
substantially treating the dermis not only reduces the down-time
and side effects of the treatment, but also increases the positive
skin-tightening effects.
[0057] Networks of treatment zones containing treatment zones that
are slanted at angles in the skin can be used to increase and
control the direction of the tension produced in the skin by the
treatment. Additionally, producing intersecting treatment zones can
further increase the tension, as regions of collagen shrinkage
become linked to other regions of collagen shrinkage and further
increase tension. Patterns of treatment zones containing treatment
zones that are slanted at angles in the skin can also be used to
increase and control the direction of the tension produced in the
skin. For example, producing a pattern of treatment zones where the
slanted treatment zones are along lines focused at a single point,
but where the treatment zones do not converge at that point, can
produce tension which `pulls` the skin toward that point.
[0058] Additionally, treatment networks or patterns can be oriented
based on skin features such as Langer's lines, Borges' lines,
Kraissl's lines, resting skin tension lines, lines of maximum
extensibility, wrinkles, underlying muscles, etc. This can result
in collagen being laid down preferentially in a desired direction
during the healing process, and/or in tightening of skin in a
desired direction. For example, orienting the treatment networks or
patterns along the same axis as a skin feature (e.g., along the
long axis of a wrinkle) can help to produce a treatment that at
least partially counteracts the natural tension of the wrinkle by
tightening the skin perpendicular to the wrinkle, thereby
stretching and minimizing the wrinkle. In one example, the
treatment networks or patterns can be made parallel with the skin
feature. In another example, the treatment networks or patterns can
be made perpendicular with the skin feature. In yet another
example, the treatment networks or patterns can be made at an angle
of between about 10 degrees and about 85 degrees with the skin
feature. Additionally, bandages or sutures can be applied to
stretch the skin and/or increase the tension in a desired direction
during the healing process.
[0059] The collagen shrinkage mechanism within the treatment zones
is further supplemented by the wound healing process. The columns
of coagulated tissue created in each of the treatment zones have
excellent mechanical integrity that supports a progressive
remodeling process without significant loss of the original
shrinkage. In addition, the coagulated tissue acts as a tightened
tissue scaffold with increased resistance to stretching. This
further facilitates wound healing and skin tightening. The
tightened scaffold serves as the structure upon which new collagen
is deposited during wound healing and helps to create a
significantly tighter and longer lasting effect.
[0060] In one example, a method for treating skin comprises:
treating a portion of skin with electromagnetic radiation in a
manner so as to create a network of treatment zones in the portion
of skin, wherein the network comprises at least four treatment
zones, at least two of the treatment zones in the network are
slanted at angles in the portion of skin, the treatment zones
extend at least as deep as a dermal-epidermal junction of the
portion of skin, at least one of the treatment zones in the network
intersects another treatment zone in the network at a point below
an epidermal layer of the portion of skin, and the treating results
in tightening of the portion of skin.
[0061] In one example, the network comprises at least twenty
treatment zones. In another example, the network comprises at least
fifty treatment zones. In yet another example, the network has a
treatment zone density of between about 50 treatment zones (TZ) per
square centimeter and about 2000 TZ/cm.sup.2 in the portion of
skin.
[0062] In one example, the network is created essentially
simultaneously. In another example, the network is created one
treatment zone at a time. In another example, the network is
created by one pass of a handpiece over the portion of skin during
the treating. In yet another example, the network is created by at
least two passes of a handpiece over the portion of skin during the
treating.
[0063] In one example, the treatment zones extend from the surface
of the skin through an epidermal layer of the portion of skin and
into a dermal layer of the portion of skin. In another example, the
treatment zones extend from a lower epidermal layer of the portion
of skin into a dermal layer of the portion of skin, leaving at
least a layer of the stratum corneum substantially intact.
[0064] In one example, tissue within the treatment zones is
coagulated. In another example, tissue within the treatment zones
is necrosed. In yet another example, tissue within the treatment
zones is ablated.
[0065] In one example, each of the treatment zones in the network
intersects at least one other treatment zone in the network. In
another example, the treatment zones intersect at a point below the
dermal-epidermal junction of the portion of skin. In yet another
example, each of the treatment zones in the network a unique focal
point.
[0066] In one example, the angles at which the treatment zones are
slanted in the portion of skin are between about 10 degrees and
about 85 degrees as measured from a line substantially
perpendicular to the surface of the portion of skin. In another
example, the angles at which the treatment zones are slanted in the
portion of skin are between about 45 degrees and about 85 degrees
as measured from a line substantially perpendicular to the surface
of the portion of skin. In another example, the angles are
predetermined. In another example the angles are randomly generated
during the treating.
[0067] In one example, the skin substantially perpendicularly above
the point at which the treatment zones intersect is not treated. In
another example, the treating improves the cosmetic appearance of
wrinkles in the portion of skin. In yet another example, the method
further comprises cooling an epidermal layer of the portion of
skin. The epidermal layer can be cooled before, during or
immediately following the treating.
[0068] The two drawings in FIG. 2 illustrate a network of six
slanted, intersecting treatment zones. The drawing in FIG. 2A
illustrates a top view of the surface of the skin and shows the
tops of the treatment zones (203) at the surface of the skin which
are formed by circular treatment beams impacting the surface of the
skin. The treatment zones can be formed simultaneously or
separately. The drawing in FIG. 2B illustrates a cross-sectional
view of this network of treatment zones within the layers of the
skin. A treatment beam (201) impacts the surface of the portion of
skin (210) and forms a treatment zone (203) in the layers of the
skin. As the angle of the treatment beam is acute when measured
from a line (207) substantially perpendicular to the surface of the
skin (210), the treatment zone (203) created by the beam (201) is
similarly angled within the portion of skin. A network of treatment
zones are shown in FIG. 2B. The individual treatment zones in the
network extend from the surface of the skin (210) through the
dermal-epidermal junction of the skin (220) and into the dermal
layer of the portion of skin. The individual treatment zones (203)
intersect (230) at a point at or below the dermal-epidermal
junction of the skin (220). As the treatment zones (201) are
slanted, skin substantially perpendicularly above (240) the point
of intersection (230) is not treated by the electromagnetic
radiation. The network of intersecting treatment zones produces
tension (208) within the skin, and results in tightening of the
skin.
[0069] The two cross-sectional drawings in FIG. 3 illustrate two
different networks of treatment patterns. The drawing in FIG. 3A
illustrates a network of 54 treatment zones (303), where the
treatment zones are all slanted at angles in the skin and each of
the slanted treatment zones intersects at least one other treatment
zone in the network. Some of the slanted treatment zones intersect
two other treatment zones in the network. The treatment zones begin
below the surface of the skin (310), and intersect at a point at or
below the dermal-epidermal junction (320) of the region of
skin.
[0070] The drawing in FIG. 3B illustrates a network of 54 treatment
zones (303), where half the treatment zones are slanted (303A) in
the portion of skin and half of the treatment zones are
substantially perpendicular (303B) to the surface of the skin
(310). The treatment zones begin below the surface of the skin
(310). All of the treatment zones (303) intersect at least one
other treatment zone in the network; the majority of the treatment
zones intersect two other treatment zones in the network. Some of
the treatment zones intersect at points within the epidermal layer
of the portion of skin, and some of the treatment zones intersect
at points below the dermal-epidermal junction (320) of the region
of skin.
[0071] In some examples, as shown in FIGS. 3A and 3B, the treatment
zones can generally lie along a line. By creating a pattern of
treatment zones along a line in the tissue, the tissue can be
"pulled" with increased tension along that line to cause a
directional cinching of the tissue. This can be advantageously used
to cause anisotropic tightening within the skin, which can be
desirable for example, when lifting the eye brow in a cosmetic
treatment of skin that has sagged.
[0072] In one example, a method for treating skin comprises
treating a portion of skin with electromagnetic radiation in a
manner so as to produce a pattern of treatment zones in the portion
of skin, wherein the pattern comprises at least four treatment
zones, at least two of the treatment zones in the pattern are
slanted at angles in the portion of skin, the treatment zones
extend at least as deep as a dermal-epidermal junction of the
portion of skin, and the treating results in tightening of the
portion of skin.
[0073] In one example, the pattern comprises at least ten treatment
zones. In another example, the pattern comprises at least fifteen
treatment zones. In another example, the pattern comprises at least
twenty treatment zones. In yet another example, the pattern
comprises at least fifty treatment zones.
[0074] In another example, the treatment zones comprising the
treatment pattern are created essentially simultaneously. In
another example, the treatment zones comprising the treatment
pattern are created one at a time. In another example, the
treatment pattern is predetermined. In another example, the
treatment pattern is randomly generated during the treatment. In
yet another example, the treatment pattern is repeated in the
portion of skin during the treating.
[0075] In one example, a first treatment pattern is at least
partially overlapped with a second treatment pattern during the
treating. In one example, the first and second treatment patterns
are the same. In another example, the first and second treatment
patterns are different. In yet another example, overlapping the
first and second treatment patterns causes at least one treatment
zone in the first pattern to intersect at least one treatment zone
in the second pattern, wherein the treatment zones intersect at a
point below an epidermal layer of the portion of skin. In another
example, the treatment zones intersect at a point below the
dermal-epidermal junction of the portion of skin.
[0076] In one example, the treatment zones extend from a surface of
the portion of skin through an epidermal layer of the portion of
skin and into a dermal layer of the portion of skin. In another
example, the treatment zones extend from a lower epidermal layer of
the portion of skin into a dermal layer of the portion of skin,
leaving at least a layer of the stratum corneum substantially
intact.
[0077] In one example, each of the treatment zones in the pattern
is slanted. In another example, the slanted treatment zones are
angled in the portion of skin such that lines projected along the
length of the slanted treatment zones intersect at substantially a
single point below the surface of the skin, wherein the treatment
zones in the pattern do not extend as deep as the point and do not
intersect.
[0078] In one example, the angles at which the treatment zones are
slanted are between about 10 degrees and about 85 degrees as
measured from a line substantially perpendicular to the surface of
the portion of skin. In another example, the angles at which the
treatment zones are slanted are between about 45 degrees and about
85 degrees as measured from a line substantially perpendicular to
the surface of the portion of skin.
[0079] In one example, the treating produces a treatment zone
density of between about 50 TZ/cm.sup.2 and about 2000 TZ/cm.sup.2.
In another example, the treating produces a treatment zone density
of between about 100 TZ/cm.sup.2 and about 1000 TZ/cm.sup.2.
[0080] In one example, the treating improves the cosmetic
appearance of wrinkles in the portion of skin. In another example,
the method further comprises cooling an epidermal layer of the
portion of skin. In another example, the cooling occurs before,
during or immediately following the treating.
[0081] The drawings in FIG. 4 illustrate a top-view (FIG. 4A) and a
perspective view (FIG. 4B) of one method of producing a pattern of
treatment zones in a portion of skin. In the drawings, the pattern
is created using four beams of electromagnetic radiation (401),
each of which is aimed at the surface of the skin at different
points around the circumference of a circle (404). Similar patterns
can be produce using more than four beams, or using a combination
of slanted and substantially perpendicular treatment beams. In the
example of FIG. 4, each of the four beams is angled such that the
beams would substantially converge at a point (406) below the
surface of the skin if the beams were to penetrate that deeply into
the tissue. Lines (405) indicate the angle of the path of the beams
and substantially intersect at a single focal point (406). A line
drawn substantially perpendicular to the surface of the skin (407)
shows that the angle of the beam (401) is acute with respect to the
line (407). The treatment zones (403) are shown on the surface of
the skin in the top-view drawing (FIG. 4A) and penetrating at
angles into the tissue in the perspective drawing (FIG. 4B). The
treatment zones (403) do not penetrate into the tissue as deep as
the focal point (406) and thus do not intersect at the focal point
(406). By creating a pattern of treatment zones "aimed" in this
manner at a point deep in the tissue, the tissue can be "pulled"
toward that point, without the need to create extremely deep
treatment zones or the need to produce a region of tissue that has
been extensively damaged (i.e., a region which has been exposed to
radiation from a number of different treatment beams).
[0082] The two drawings in FIG. 5 illustrate a perspective view
(FIG. 5A) and a cross-sectional view (FIG. 5B) of a pattern of five
treatment zones in a portion of skin. Similar patterns can be
produce using more than four beams, or using a combination of
slanted and substantially perpendicular treatment beams. For
example, a number of treatment beams could be directed to the
"back" half of the circumference of the ellipse (504). In the
example shown in FIG. 5, five treatment beams (501) impact the
surface of the skin (510) at five points (502). The five points
(502) where the five treatment beams impact the surface (510) of
the skin are located on the circumference of an ellipse (504). As
each treatment beam (501) impacts the surface of the skin (520) at
point (502), it creates a treatment zone (503) below the stratum
corneum layer of the epidermis. These treatment zones extend past
the dermal-epidermal junction (520) and into the dermal layer of
the skin. Due to the angle of each treatment beam (501), each
treatment beam (501) creates slanted treatment zone (503) in the
portion of skin. Viewed in cross-section, the treatment zones can
appear as ellipses, circles or columns, depending upon the angle at
which the treatment zone is slanted in the portion of skin and the
treatment parameters used.
[0083] The two drawings in FIG. 6 illustrate a perspective view
(FIG. 6A) and a cross-sectional view (FIG. 6B) of the pattern from
FIG. 5 being repeated three times (604U, 604V, 604W) in a portion
of skin. In this example, the three patterns (604U, 604V, 604W) are
the same and are not overlapped. The treatment zones (603) extend
from the surface of the skin (610) through the dermal-epidermal
junction (620) and into the dermal layer of the skin.
[0084] The two drawings in FIG. 7 illustrate a perspective view
(FIG. 7A) and a cross-sectional view (FIG. 7B) of the pattern from
FIG. 5 being repeated three times (704X, 704Y, 704Z) in a portion
of skin. In this example, the three patterns (704X, 704Y, 704Z) are
the same and are partially overlapped. The treatment zones (703)
extend from the surface of the skin (710) through the
dermal-epidermal junction (720) and into the dermal layer of the
skin. Due to the overlapping of the patterns, at least one
treatment zone (703) from each of the patterns intersects (730) at
least one treatment zone from another pattern. The point at which
the treatment zones (703) intersect (730) is below the
dermal-epidermal junction, and the skin perpendicularly above the
point of intersection (730) remains untreated.
[0085] The methods for treating skin described herein, which
involve creating networks or patterns containing slanted
treatments, wherein the treatment zones extend at least as deep as
the dermal-epidermal junction, can be accomplished using a number
of different devices. In one example, the device comprises a
handpiece operably coupled to a delivery element, wherein delivery
of electromagnetic radiation through the device to a portion of
skin produces a network of at least four treatment zones, at least
two of the treatment zones are slanted at angles in the portion of
skin, the treatment zones extend at least as deep as a
dermal-epidermal junction of the portion of skin, and at least one
of the treatment zones intersects another treatment zone in the
network. In one example, the treatment zones intersect at a point
below an epidermal layer of the portion of skin. In another
example, the treatment zones intersect at a point below the
dermal-epidermal junction of the portion of skin. In yet another
example, skin substantially perpendicularly above the point at
which the treatment zones intersect is not treated.
[0086] In another example, the device comprises a handpiece
operably coupled to a delivery element, wherein delivery of
electromagnetic radiation through the device to a portion of skin
produces a pattern of at least four treatment zones, at least two
of the treatment zones in the pattern are slanted at angles in the
portion of skin, and the treatment zones extend at least as deep as
a dermal-epidermal junction of the portion of skin. In another
example, all of the treatment zones in the pattern are slanted at
angles in the portion of skin. In another example, the slanted
treatment zones in the pattern are slanted at angles such that
lines projected along the length of each treatment zone intersect
at substantially a single point below an epidermal layer of the
portion of skin, wherein the treatment zones in the pattern do not
extend as deep as the point and do not intersect.
[0087] In one example, the delivery element of the device comprises
an array of optical fibers configured to deliver beams of
electromagnetic radiation at a variety of angles. In another
example, the delivery element comprises a scanner operably coupled
to a lens. In another example, the scanner comprises a rotating
scanner. In another example, the scanner comprises a starburst
scanner. In another example, the scanner is capable of creating
beams of electromagnetic radiation at different angles. In another
example, the scanner comprises a 2-dimensional scanner and the lens
comprises a lens with a numerical aperture between about 0.25 and
about 1.4. In another example, the scanner comprises a
1-dimensional scanner and the lens comprises a cylindrical lens,
wherein the scanner and the axis of the lens are not aligned. In
yet another example, the scanner comprises two galvanometer
scanners.
[0088] In one example, the electromagnetic radiation is continuous.
In another example, the electromagnetic radiation is pulsed. In one
example, delivery of electromagnetic radiation through the device
to a portion of skin results in multiple beams of electromagnetic
radiation being directed to the surface of the skin as the device
is moved across the skin. In another example, delivery of
electromagnetic radiation through the device to a portion of skin
results in multiple beams of electromagnetic radiation being
directed to the surface of the skin as the device is placed at
multiple location on the surface of the skin.
[0089] In one example, delivery of electromagnetic radiation
through the device to the portion of skin produces tightening of
the portion of skin. In another example, the device is used to
improve the cosmetic appearance of skin. In yet another example,
the device is used to improve the cosmetic appearance of wrinkles
in the portion of skin.
[0090] In one example, the device further comprises a cooling
means. In one example, the cooling means comprises a cooling
surface. In another example, the cooling means comprises a sprayer
which dispenses a cooling liquid. In another example, the cooling
means comprises a surface cooled using a liquid.
[0091] FIG. 8 is a cross-sectional drawing which illustrates a
device for treating skin using electromagnetic radiation. It
includes a handpiece (850) operable coupled to a delivery element
(840). The delivery element (840) can optionally be located inside
the handpiece. A source of electromagnetic radiation (830) can
optionally be operably coupled to the delivery element (840). When
the handpiece (850) is placed in contact with the surface of a
portion of skin (810), beams of electromagnetic energy (801) can be
directed through the delivery element and through the handpiece to
impact the surface of skin (810) at a point (802) and create a
treatment zone (803) in the portion of skin. This device can be
used to create networks of treatment zones containing slanted
treatment zones (803) which intersect below the dermal-epidermal
junction (820). It can also be used to create patterns of treatment
zones containing slanted treatment zones which penetrate at least
as deep as the dermal-epidermal junction (820). This device can be
used for cosmetic and/or medical purposes, such as to treat
wrinkles and to tighten skin.
[0092] FIG. 9 is a cross-sectional drawing which illustrates
another device for treating skin using electromagnetic radiation.
It includes a handpiece (950) operably coupled to a delivery
element (940). The delivery element (940) can, for example, be a
collimating or focusing lens assembly. The delivery element (940)
can optionally be located in the handpiece (950). In this example,
the handpiece contains a mirror (960) and a starburst scanner
(970). Starburst scanners are described generally in copending U.S.
patent application Ser. No. 11/158,907. The starburst scanner (970)
pictured in FIG. 9 includes facets that are not perpendicular to
the plane of the paper. These facets are used to create a two
dimensional pattern of beams on the surface of a focusing lens
(980). Appropriate curvature can be added to the facets as desired
for focusing or translating the beams. The device can be used to
create a pattern of treatment zones in a portion of skin when
electromagnetic radiation passes through the delivery element (940)
and the handpiece (950) to a surface of a portion of skin (910).
The beam of electromagnetic radiation (901) passes from the
delivery element (940) into the handpiece (950) and is deflected by
the mirror (960) onto a first facet of the starburst scanner (970),
where it is again deflected off a second facet of the starburst
scanner (970) and then passes through a lens (980) before impacting
the surface of the skin (910). The facets of the starburst scanner
are angled such that as the beam (901) impacts the facet, it is
deflected at an angle. The different facets of the scanner can have
different angles, resulting in the beam being deflected at
different angles as the scanner rotates. Beam (901A) represents a
beam that has been deflected in front of the plane of the drawing,
while beams (901B) and (901C) represent beams that have not been
deflected out of the plane of the drawing. In this manner, the beam
can be deflected, creating points of impact on the surface of the
skin in a particular shape, such as, for example, around the
circumference of a circle or ellipse. Additional facet pairs in the
starburst scanner can deflect the beam to other points in a circle
near the perimeter of the lens (980). This arrangement can thus be
used to create lesions as depicted, for example, in FIGS. 4A and
4B. In the example, the beams pass through a lens (980) before
impacting the surface of the skin (910) and producing treatment
zones (903) in the portion of skin. Due to the deflection of the
treatment beam (901C, 901D) at different angles, some or all of the
treatment zones (903) can be slanted at angles in the portion of
skin. Alternatively, the delivery element (940) can deliver the
beam (901) to a pair of galvanometer scanners that are configured
to reflect the beam (901) to the lens (980). The galvanometer pair
can be arranged such that one galvanometer deflects the beam in the
"x-direction" on the skin and the other deflects the beam in the
"y-direction" on the skin, thus allowing the selection of any 2
dimensional pattern desired on the focusing lens (980). This
configuration can thus be used to create a pattern of treatment
zones such as the ones shown in FIGS. 4, 5, and 9. These devices
can be used for cosmetic and/or medical purposes, such as to treat
wrinkles and to tighten skin.
[0093] Various forms of electromagnetic radiation can be used in
accordance with the methods and devices described herein, including
ultraviolet radiation, visible light, infrared radiation, radar,
and radio waves. The electromagnetic radiation can be coherent in
nature, such as laser radiation, or non-coherent in nature, such as
flash lamp radiation. The coherent electromagnetic radiation can be
produced by one or more lasers, including gas lasers, dye lasers,
metal-vapor lasers, and/or solid-state lasers. The laser can be
ablative or non-ablative. The type of lasers used in accordance
with this invention can be selected from the group consisting of an
argon ion gas laser, a carbon dioxide (CO.sub.2) gas laser, an
excimer chemical laser, a dye laser, a neodymium yttrium aluminum
garnet (Nd:YAG) laser, an erbium yttrium aluminum garnet (Er:YAG)
laser, a holmium yttrium aluminum garnet (Ho:YAG) laser, an
alexandrite laser, an erbium doped glass laser, a neodymium doped
glass laser, a thulium doped glass laser, an erbium-ytterbium
co-doped glass laser, a fiber laser, an erbium doped fiber laser, a
neodymium doped fiber laser, a thulium doped fiber laser, an
erbium-ytterbium co-doped fiber laser, and combinations
thereof.
[0094] In one example, the wavelength of the laser radiation can be
a wavelength that is absorbed within the skin primarily by water,
such as, for example, the wavelengths between about 1300 nanometers
(nm) and about 12,000 nm. Depending on the desired depth of
treatment and desired treatment zone size, the wavelength of the
laser radiation used can be selected from the group consisting of
between about 1250 nm and about 2500 nm, between about 1280 nm and
about 1350 nm, between about 1400 nm and about 1500 nm, between
about 1500 nm and about 1620 nm, between about 1780 nm and 2000 nm,
and combinations thereof. Wavelengths longer than 1500 nm can be
used if the goal is to get deep penetration with small treatment
zones. The shorter wavelengths generally have higher scattering
coefficients than the longer wavelengths.
[0095] The spot size of a treatment beam is the size of the beam of
electromagnetic radiation at the point when it hits the surface of
the target tissue, and is measured based on the cross-sectional
width or diameter of the beam. Spot size can be selected based on
the desired depth of the treatment zone and/or the desired healing
time for the treatment zone. In accordance with this invention, the
spot size can be selected from the group consisting of between
about 0.5 .mu.m and about 500 .mu.m, between about 1 .mu.m and
about 360 .mu.m, between about 1 .mu.m and about 250 .mu.m, between
about 1 .mu.m and about 180 .mu.m, about 60 .mu.m, and about 140
.mu.m.
[0096] The treatment zone density is the number of treatment zones
that are created within the portion of tissue undergoing treatment.
Treatment zone density can be selected based on the aggressiveness
of the treatment desired. The treatment zone density can also be
selected in conjunction with the spot size so as to achieve a
desired "fill factor" of treatment zones within a volume of tissue.
The treatment zone density can be selected in conjunction with the
treatment zone angle and depth to ensure treatment zones intersect
each other. The treatment zone density can also be selected based
on the number of intersecting treatment zones and/or overlapping
treatment patterns desired, as increasing the density can increase
the number of intersecting treatment zones and/or overlapping
treatment patterns. When expressed as a fill factor, the treatment
zone density can be between about 0.05 and about 0.95, or between
about 0.1 and about 0.5. When expressed as the number of treatment
zones created in a region of skin, the treatment zone density can
be selected from the group consisting of between about 100 and
10,000 treatment zones per square centimeter (TZ/cm.sup.2), between
about 100 and about 2000 TZ/cm.sup.2, between about 100 and about
1000 TZ/cm.sup.2, and between about 100 and about 500 TZ/cm.sup.2
of treated region of tissue.
[0097] While a major focus of the methods and devices described
herein is tightening the skin and improving the cosmetic appearance
of wrinkles, these methods and devices are suitable for treatment
of a variety of biological tissues in addition to skin. Other
biological tissues which can be treated with these methods and
devices include tissues with structures similar to human skin, such
as, for example, tissues that have an epithelium and underlying
structural tissues, such the soft palate.
[0098] Similarly, while these methods and devices can be used for
cosmetic or medical purposes to remodel tissue (for example, for
collagen remodeling), to resurface tissue, and/or to treat wrinkles
and photoaging of the skin, they are also suitable to treat a
variety of dermatological condition such as hypervascular lesions
including port wine stains, capillary hemangiomas, cherry angiomas,
venous lakes, poikiloderma of civate, angiokeratomas, spider
angiomas, facial telangiectasias, telangiectatic leg veins;
pigmented lesions including lentigines, ephelides, nevus of Ito,
nevus of Ota, Hori's macules, keratoses pilaris; acne scars,
epidermal nevus, Bowen's disease, actinic keratoses, actinic
cheilitis, oral florid papillomatosis, seborrheic keratoses,
syringomas, trichoepitheliomas, trichilemmomas, xanthelasma,
apocrine hidrocystoma, verruca, adenoma sebacum, angiokeratomas,
angiolymphoid hyperplasia, pearly penile papules, venous lakes,
rosacea, etc. While specific examples of dermatological conditions
are mentioned above, it is contemplated that these methods and
devices can be used to treat virtually any type of dermatological
condition. Additionally, these methods and devices can be applied
to other medical specialties besides dermatology.
[0099] Although the detailed description contains many specifics,
these should not be construed as limiting the scope of the
invention but merely as illustrating different examples and aspects
of the invention. It should be appreciated that the scope of the
invention includes other embodiments not discussed in detail above.
Various other modifications, changes and variations which will be
apparent to those skilled in the art may be made in the
arrangement, operation and details of the method and apparatus of
the present invention disclosed herein without departing from the
spirit and scope of the invention as defined in the appended
claims. Therefore, the scope of the invention should be determined
by the appended claims and their legal equivalents. Furthermore, no
element, component or method step is intended to be dedicated to
the public regardless of whether the element, component or method
step is explicitly recited in the claims.
[0100] All publications, patents and patent applications cited
herein, whether supra or infra, are hereby incorporated by
reference in their entirety.
[0101] In the claims, reference to an element in the singular is
not intended to mean "one and only one" unless explicitly stated,
but rather is meant to mean "one or more." In addition, it is not
necessary for a device or method to address every problem that is
solvable by different embodiments of the invention in order to be
encompassed by the claims.
* * * * *