Principles of Selective Photothermolysis
Selective
Photothermolysis refers to selective absorption
of laser light pulses by a target chromophore.
The curve representing laser wavelengths vs. absorption
coefficient for each of the target chromophores is referred
to as an absorption spectrum. The specific absorption
criteria for the various target chromophores will be discussed
in more detail in the following text.
To achieve selective photothermolysis, laser pulses must
be short in duration to sufficiently deposit enough energy
in the target tissues before they can cool, thus achieving
appropriate and localized heating. As soon as the
target is heated, it begins to dissipate heat through
conduction and radiation.
The time required for significant cooling of the target
chromophore is known as the thermal relaxation time.
It is the time necessary for the target chromophore
to cool down by 50% through transfer of its heat to surrounding
tissues through thermal diffusion.
To limit the amount of thermal damage to the intended
target, the pulse duration must be shorter than the thermal
relaxation time of the target tissue. This significantly
decreases the potential damage to tissues surrounding
the target chromophore.
To summarize the principle of selective photothermolysis,
three necessary elements are required:
1.
Exposure
or pulse duration less than the thermal relaxation time
of the target.
2.
A
wavelength that reaches, and is preferentially absorbed
by, the chromophores in the desired target tissues
3.
The
proper fluence to reach a damaging temperature in the
target tissue without damaging surrounding tissue structures.
Selective Photothermolysis of Vascular Lesions
The basis of laser treatment for vascular lesions is the
destruction of abnormal vessels by absorption of laser
energy without damaging surrounding tissue.
The principle of selective photothermolysis is defined
as the targeting of a precise dosage of intense photo-thermal
energy at a specific wavelength to a specific structure,
a chromophore, to achieve selective destruction
of a target.
In benign vascular lesions, hemoglobin is the chromophore,
which absorbs the intense energy.
Figure 1: Absorption curves of melanin and Oxyhemoglobin
The Pulsed Dye Laser; when adjusted to the correct wavelength,
pulse width, and fluence combinations; selectively damages
abnormal blood vessels (containing the target chromophore,
hemoglobin). The wavelength(s) and pulse width(s)
available for treatment are designed into the laser by
the laser manufacturer.
Wavelength
When considering a wavelength to treat vascular lesions,
a wavelength that is well absorbed by the hemoglobin and minimally absorbed by competing chromophores, like melanin, is desirable.
It is well documented that hemoglobin peaks at 420 nm,
540 nm and 577nm. Longer wavelengths penetrate the
tissue deeper than shorter wavelengths. Although the blood
vessels contain both oxy- and deoxy-hemoglobin, only oxyhemoglobin,
which is the dominant component (over 80%, in red vessels)
is shown here.
Originally, 577nm was the wavelength chosen for pulsed
dye lasers. It proved good penetration and absorption
by hemoglobin. However, further studies have shown
that wavelengths from 585 to 595 nm provide deeper penetration
with insignificant difference in absorption by hemoglobin.
As the laser light passes through the epidermis to the
target vessels, it is absorbed by the hemoglobin and converted
into heat within the abnormal vessel walls. Normal
sized vessels are also heated, but because they are much
smaller, they conduct heat away much more rapidly and
do not reach temperatures high enough to cause coagulation.
The heating of the vessel walls causes coagulation or
destruction of the vessel.
Figure 2: Wavelength relationships of various vascular
lasers
Pulse Duration
The pulse duration time or exposure time is critical because
it must be less than the thermal relaxation time of the
target. Thermal relaxation time is defined as the
time necessary for the target vessel to cool down by 50%
through transfer of heat to surrounding tissues.
Figure 3: How pulsewidth affects peak power output for
a given amount of energy.
When utilizing the longer pulse duration, larger diameter
vessels are targeted with a decreased purpuric response
and a decreased melanin absorption in skin types IV-VI.
Laser Safety Guidelines
Regulating Bodies
1) American National
Standards Institute
[ANSI] - This organization provides standards for appropriate
clinical use of lasers. This is a non-governmental organization
of experts from trade associations, technical societies,
professional groups and consumer organizations; who determine
appropriate design and procedural standards in various
fields. These standards are intended for both users and
manufacturers. The published standards for use with lasers
are referred to and identified as ANSI Z136.1 (Safe use
of Lasers) and ANSI 136.3 (Safe use of Lasers in health
care facilities). The Joint Commission on Accreditation
of Hospitals Organization [JCAHO] follows these standards
when evaluating the efficacy of a hospital based laser
program. The safety precautions listed in this outline
are based on the ANSI recommendations.
2) Food
and Drug Administration, Center for Devices and Radiologic
Health
[FDA CDRH] - The CDRH regulates the manufacture and distribution
of lasers. This agency an arm of the Food and Drug Administration
[FDA] responsible for regulation of medical devices. Once
a manufacturer has demonstrated safety and effectiveness
of a device, the FDA, under pre-market notification [510(k)]
or Pre-Market Approval [PMA] may clear the laser for commercial
distribution for the specific indication(s). CDRH standards
classify all medical devices into three classes according
to general hazard potential. The cutaneous lasers
produced by Cynosure, Inc. are Class II medical devices.
All lasers are further classified into four categories,
based on their hazard potential. The cutaneous lasers
produced by Cynosure, Inc. are Class IV laser devices
and require specific safety precautions be taken in conjunction
with their use.
3) Occupational
Safety and Health Administration
[OSHA] - This regulatory agency, within the U.S. Department
of Labor is primarily responsible for assuring worker
safety in industries. OSHA is concerned with the physical
environment of the laser room setting relating to safety,
such as power cord placement and fume hazards. This agency
relies primarily on ANSI Z136.1 standards, along with
a variety of other appropriate standards.
4) State
Regulations - The
laws and regulations vary from state to state. The regulations
are based on the ANSI standards and may require appointment
of a laser safety officer [LSO], and reporting any injury
or mishap to the state agency.
5) Local
Requirements
- These regulations vary locally and range from none,
to yearly inspection and certification. With the acquisition
of a laser, the purchaser should become familiar with
local requirements.
6) Medical
Facilities -
As in all governmental affairs, the best and most important
decisions are exercised by local control. For large medical
facilities with many types of lasers, it is essential
and necessary that a laser safety committee be established
to monitor safe use of lasers in the medical facility.
The committee should provide proper credentialing criteria
to the appropriate hospital committee(s). The recommended
members of the committee should include representatives
from all surgical and medical services, which use lasers,
along with representatives from the nursing services,
surgical chief, and biomedical engineering and/or LSO.
General Laser Safety
The laser safety precautions suggested in this section
are recommendations from the American National Standard
for Safe Use of Lasers in Health Care Facilities (ANSI
136.3) and should not be considered as all-inclusive.
A copy of the ANSI standards can be obtained by contacting:
Laser Institute of America
12424 Research Parkway
Suite 125
Orlando, FL 32826
Phone: 407-380-1553
Fax: 407-380-5588
Laser Suite
1. Warning signs
for laser exposure must be placed on all doors allowing
entrance into the laser treatment area.
2. The
signs must display "Danger" or "Warning", the type and
wavelength of laser in use. The sign dimensions, letter
size and color, etc. should be in accordance with ANSI
Z35.1, the specification for accident prevention signs.
3. Safety
interlock systems may be installed to deactivate the laser
system whenever a door to the laser treatment room is
opened.
4. Appropriate
protective eyewear should be placed outside of the laser
treatment room to facilitate safe entry.
5. All
viewing windows should be covered with opaque material
or a window filter specific for the wavelength being used,
in order to prevent inadvertent escape of laser light.
Eyewear
1. Protective eyewear
of the correct optical density for the specific wavelength
must be worn at all times during the laser procedure.
2. All
protective glasses or goggles must bear a label from the
manufacturer identifying the wavelengths for which their
use is intended, and the optical density of those wavelengths.
3. All
protective eyewear must have side shields for protection.
4. When
cleaning eyewear, do not use solvents or abrasives that
might remove the protective coating. Use mild soap and
water only.
5. Replace
eyewear if they become scratched, chipped or if the protection
is in any way compromised.
6. Contact
lenses do not provide adequate protection and laser protective
eyewear must be worn.
7. Patients
must also have eye protection. They may wear the protective
laser goggles during treatment if they do not interfere
with access to the treatment area.
8. If
treating near the eye, a stainless steel eyeshield is
necessary. Administering an ophthalmic anesthetic prior
to insertion and an ophthalmic lubricant to the surface
of the eye shield will alleviate any discomfort.
9. Keep
reflective objects out of the treatment field to avoid
accidental reflection. Remember that stainless steel eyeshields
may cause some reflection of the laser beam.
10. Even
when wearing protective eyewear, one should never look
directly into the path of the laser, as this may cause
permanent eye damage. In addition, direct exposure to
the laser beam can cause permanent damage to the safety
eyewear lens and void the warranty.
11. Laser
safety eyewear should be stored away from direct sunlight
to prevent degradation of the absorbing media, such as
photobleaching.
Operators of the Laser System
1. A laser-trained
nurse or technician should be responsible for enforcing
safety guidelines, and manning the laser during operation.
2. Check
the laser prior to every procedure, before admitting the
patient into the room.
3. The
operating laser physician and the laser operator should
attend the appropriate laser-training course and should
receive certification and/or credentialing prior to patient
treatment.
4. Laser
finger switch or foot pedal should be controlled by the
operator only, to prevent accidental firing of the laser.
5. Laser
firing should only be enabled once the operator has positioned
the laser handpiece over the treatment area.
6. Leave
the laser in standby mode when not in use.
7. Never
leave the key in the key switch when the laser is not
in use. The key should be stored in a separate location,
in a locked box, to prevent unauthorized personnel from
using the system.
Electrical Safety
1. The PhotoGenica
V-Star pulse dye laser uses extremely high voltage. These
high voltages are not accessible unless the protective
housing is opened. Do not open the protective panels unless
trained and authorized to do so.
2. Servicing
high voltage and other components is to be done only by
a Cynosure authorized service representitive.
3. The
laser should never be left turned on while opened. Or
left unattended when performing maintenance.
Chemical Hazards
1. The PhotoGenica
V-Star pulse dye laser uses liquids that the operators
should handle with care. A Material Safety Data Sheet
[MSDS]will be made available on request.
2. Although
these liquids exhibit low toxcicity, they should be handled
cautiously. When handling dye, wear rubber gloves and
keep the liquid away from flames.
3. Securely
wrap the caps of used bottles with adhesive tape and return
to Cynosure along with the used filter, as per the instructions
enclosed in the packaging.
4. Never
dispose of liquids down the drain. Always return them
to Cynosure where they will be disposed of properly (by
incineration) by an approved waste disposal group who
specializes in handling these types of liquids.
5. If
an accidental dye exposure does occur, please follow these
first aid suggestions:
Skin Exposure - Immediately
wash the exposed area with water, than with soap and water
Eye Exposure - Flush eyes
with water or eye rinse. Seek medical attention if symptoms
arise
Inhalation - Go outdoors
to inhale fresh air. Seek medical attention if symptoms
arise
Ingestion - Drink water,
induce vomiting and call physician
Fire Hazards
1. The laser dye
concentrate and dye additive that are used in PhotoGenica
pulsed dye lasers are flammable. Anyone handling these
liquids should be aware of this and should keep the dye
away from direct flames.
2. Flammable
preparations such as alcohol or acetone should not be
used in the presence of operating lasers. If alcohol is
used for disinfection of the skin, allow the area to dry
completely before using the laser.
3. Water
should always be available to extinguish any flames.
4. Be
especially careful with the use of oxygen. In the event
of fire, oxygen will accelerate the combustion of fire.
5. If
using gauze in the treatment area, always moisten with
water first.
6. When
treating an area with hair, be sure to wet the hair with
water or surgical lubricant before treatment begins to
prevent singing or burning. If the amount of hair is excessive,
it should be shaved prior to laser treatment.
7. Know
the location of the nearest fire extinguisher.
Proper Laser Handling and Storage
1. Only qualified
and trained personnel should be assigned to install, adjust
and operate the laser equipment.
2. Cynosure
Suggests that the operators periodically clean and disinfect
the exterior of the laser system with a mild soap and
water using a soft cloth. Do not immerse, soak
or autoclave the fiber optic or handpiece.
3. After
each patient treatment the portion of the handpiece that
came in contact with the patient¹s skin should be wiped
down with an alcohol prep pad. Allow time for the
alcohol to dry before pulsing the laser.
4. Be
careful not to contaminate the optics with any substance
used for cleaning and disinfecting. It is also important
not to set liquids of any kind on top of the laser.
5. The
accessories may be stored in an area accessible only to
qualified and trained employees.
6. Keeping
the storage environment free of dust particles and non-corrosive
substances such as salts and acids will aid in maintaining
the laser system.
7. For
specific information on storing the laser, please reference
the Operator¹s Manual.
8. Examine
the handpiece optic to check for the accumulation of debris
on the lens. This is more commonly seen when treating
warts or hair-bearing areas.
9. To clean
the handpiece lens, use a Q-tip moistened with 95% pure
alcohol.
Protective Laser Accessories
Eyewear:
Laser spectacles and goggles may be ordered through Cynosure,
Inc. by calling 800-886-2966. When ordering, please indicate
the specific laser wavelength and style (spectacles of
goggles) of eyewear preferred.
Eyeshields: Stainless steel eyeshields are
available through Stefanovsky and Associates by calling
216-944-4482. They are available in sets of two in adult,
child, infant, or neonatal sizes. They shields are recognized
by ANSI for safety compliance and cost approximately $400.00
per pair.
Protective Film: Protective film can be
used to cover viewing windows in the laser suite. Protective
windows may also be customized to window specifications.
For ordering information, contact the suppliers below:
Bilsom Group / Glendale Protective Technologies
109 Carpenter Drive
Sterling, VA 20164
Phone: 1-800-645-7530 Uvex Winter Optical
10 Thurber Blvd.
Smithfield, RI
Phone: 1-800-343-3411
(custom windows)
Industrial Safety Products
6091 Carey Drive
Cleveland, OH 44125
Phone: 216-524-0360
(Acrylic Sheeting)
Chapter 3
Laser Operation
Please refer to the V-Star Operator's Manual
Chapter 4
Clinical Applications
This section of the manual discusses the clinical application
of the PhotoGenica V-Star Laser in general terms. The
section covers training requirements, indications, contraindications,
possible adverse effects, patient selection, and treatment
recommendations.
Laser Operator Training Requirements
This manual is not intended to be a complete guide to
the use of the PhotoGenica V-STAR Laser. Cynosure
recommends that all qualified personnel who operate the
laser system first seek training that includes, but is
not limited to, the following aspects of laser operation:
* Basic Laser Physics
* Laser Safety
* Laser/Tissue Interaction
* Laser Operating Procedures
* Laser Set-Up Procedures
* Potential Hazards
* Hands-On Experience
Indications, Contraindications, And Adverse Effects
INDICATIONS
The PhotoGenica V-STAR Laser is indicated for the treatment
of benign cutaneous vascular or vascular dependent lesions.
CONTRAINDICATIONS
Therapy using the PhotoGenica V-STAR Laser is contraindicated
for those patients who:
* are hypersensitive to light in the
585 nm or 600 nm wavelength region.
* have a family history of skin cancer.
* are pregnant.
ADVERSE EFFECTS
Adverse effects, such as scarring, hypopigmentation, and
hyperpigmentation, may result from the use of excessive
energy levels.
Patient Selection
The best candidates for treatment with the PhotoGenica
V-STAR laser are the following:
* Patients with benign cutaneous vascular
or vascular dependent lesions.
* Patients who have previously undergone
unsuccessful alternative treatment for vascular lesions,
providing that the previous treatment did not cause excessive
damage or scarring.
Pre-Treatment Recommendations
At the time of the initial visit, the physician should
determine the suitability of the laser treatment, inform
patients about the treatment, and take photographs of
the vascular lesion.
Determine Suitability
In determining suitability, physicians should consider
the following factors for each individual case:
* Type of lesion
* Color of lesion
* Patient's age
* Location of lesion
* Patient's skin type
* Family history of the patient
* Reason patient is seeking treatment
* Patient's expectations
Inform Patient About the Treatment
After determining suitability, the physician should inform
the patient of the following:
* The expected outcome of the treatment
vs. other possible outcomes
* The number of treatments it is likely
to take to achieve the desired outcome
* Possible side effects resulting from
laser treatment.
* The gradual clearing of the lesion
Photographs
It is helpful to have photographs of the pre-treated lesions
in order to precisely assess the success and progression
of the treatment.
Chapter 5
Treatment Parameters and Techniques
Lesions amenable to therapeutic and cosmetic vascular
treatments
Angiokeratoma
Are discrete
pink to red telangectatic lesions which commonly occur
on the feet and legs. They are often characterized
by changes that involve thickening or hyperkeratinization
of the epidermis.
Cherry Angioma
Are small, bright red to purple colored, papular lesions
that is usually found on the trunk and proximal extremities.
Onset may be early adult, becoming more common with
age.
Erythematous Hypertrophic Scars
Are red, raised, smooth scar containing linear or
arborizing arteriolar telangiectasia. Usually, they
are more visible and may cause the patient pain and itching.
Treatment with the laser can eliminate the vessels
and may also reduce the bulkiness of the scar and normalize
the surface texture.
Hemangioma
Are superficial to deep collection of tortuous vessels
that are raised above the skin surface. May be present
at birth, but more commonly present after the first few
days to weeks of life. May be disfiguring and the
cause of significant morbidity. Visual impairment
and airway obstruction may cause significant problems.
Small, proliferate lesions may be successfully treated
with the laser. The laser may arrest proliferation,
induce involution and assist in healing ulcerated areas.
Large hemangiomas may require surgical and pharmaceutical
intervention.
Poikiloderma of Civatte
Is a skin disorder characterized by telangiectasia
associated with atrophic changes of the skin as well as
irregularity of pigmentation. Commonly found on
the upper chest and lateral neck excluding the submental
area. It can be casused by chronic sun exposure
and use of perfumes or colognes in this area.
Port Wine Birthmark
Are vascular birthmarks that range in color from pale
pink to dark purple. Primarily located on the face
and neck, it can also cover the arms, legs and trunk and
usually unilaterally. The reported incidence is
0.3%. The lesion is flat initially, but adults in
the third decade of life may experience the development
of modularity. Response of treatment varies with
color, maturity, depth and nodularity of the lesion.
Pyogenic Granuloma
Are solitary capillary hemangioma often associated
with trauma or local irritation. Occurs on both
skin and mucus. Appears initially as a red
papule that enlarges and may pedunculate or become infected
and ulcerates. Granulomas bleed readily and are
usually painful for the patient.
Rosacea
A chronic reddening of the mid face often associated
with telangiectasia, acute episodes of edema, papules
and pustules (acne rosacea).
Spider Angioma
The characteristic central papule and radiating branches
distinguish this lesion from linear vessels found in other
types of telangiectasia. Commonly seen in preschool
and school age children.
Striae (stretch marks)
A fine pinkish-white or gray line or band elevated
above or depressed below surrounding tissue. Usually
seen in parts of the body where the skin has been stretched.
Commonly seen on thighs, abdomen and breasts of
women who are or have been pregnant.
Telangiectasia
Are acquired (chronic sun exposure) or congenital,
permanent dilatation of the capillaries, marked by superficial
vessels that range in color from red to purple. Most
frequently seen on the nose, cheeks and chin, but can
also be found on the lower extremities. One of the
most common vascular lesions seen by the general Dermatologist
with a reported incidence of 30% in the general population.
Venous Lakes
A collection of dilated lake-like venules in the upper
dermis that are flat or slightly raised. These lesions
are soft, dark blue to purple in color, average 2-10 mm
in diameter and may bleed with trauma. Commonly
seen on the lips or ears of the elderly.
Verruca (warts)
Represent benign tumors of epidermal cells induced
by the human papillomavirus. They occur in about
10% of adults and children. Because of the neovascularization
in the proliferating wart, laser vaporization is extremely
effect as it specifically targets the blood supply. Pulsed
Dye treatment can be achieved without creating a laser
plume.
Scar Prevention
Pro-active: Planned part of every surgical case.
Prevents scar from ever becoming Hypertrophic, stiff
or Erythematous.
Mechanism: Vessel ablation or vascular destruction
causes thrombosis, vasculitis and ischemia. This
affects collagen production. The process of collagen
buildup (associated with scar hypertrophy) is interrupted.
Leg Veins (red)
Post sclerotherapy in order to clear the ³matting²
effect.
Acne Scars
Erythematous and Hypertrophic scars only. Not
effective on atrophic scars (pitted/indented).
Classification of Skin Types
When treating benign vascular lesions, the ideal treatment
should result in optimal clearing without signs of hypopigmentation
or hyperpigmentation, scarring or textural changes. Keep
in mind that individual skin types may influence overall
effectiveness of the laser treatment. Classifications
of the various skin types are as follows:
I. Always burns,
never tans
II. Always
Burns, tans with difficulty
III. Sometimes
mildly burns, average tanning
IV. Rarely
burns, tans with ease
V. Very
rarely burns, tans very easily (moderately pigmented)
VI. Black
Patients with skin types I and II will respond better
than those with deeply pigmented skin. This is due
to the fact that melanin competes with the hemoglobin
chromophore for light absorption and ultimately, can interfere
with a vascular laser treatment. There is an increased
concentration of melanin in skin types V and VI. When
treating these skin types, be aware that there will be
a reduction of vascular damage in the dermis and an increase
in epidermal effects. Test spots are strongly recommended
prior to treating any type of lesion in the darker skin
types.
Contraindications
Potential contraindications should be considered prior
to treating with the Photogenica V-Star:
1. Photosensitivity
in the 595 nm range.
2. Taking
medication which is known to increase sensitivity to sunlight.
3. Taking
anticoagulants.
4. Seizure
disorders triggered by light.
5. Family
history of skin cancer.
6. Recent
sun exposure: including tanning beds and sunless
tanning creams.
Test Sites
Test sites are recommended prior to treating vascular
lesions such as Port Wine birthmarks or lesions found
in darker skin types. The tissue response following
the test dose and healing phase (approximately 6 weeks)
will help determine the energy density parameters necessary
to effectively treat the lesion.
Patients that present with telangiectasias, angiomas and
hemangiomas are usually treated at the initial session
using a safe fluence range for that specific lesion.
Test doses should be administered in an inconspicuous
location if possible. However, the test site should
be given in the same general area of the bulk of the lesion.
The test dose may be performed at 3-4 different energy
levels and may consist of single or multiple pulses. Multiple
pulses should be delivered in a non-overlapping, but adjacent
fashion.
If the patients¹ birthmark covers the face, neck and chest,
it is best to test the facial area because the better
response is expected on the neck and chest. Testing
the neck and chest area will most likely over estimate
the results expected on the face.
When evaluating test sites, the lowest energy utilized
to produce clearing should be used in subsequent treatments.
If the tissue shows no response or a mottled
appearance, the energy level was probably too low.
A test site that is blanched and de-pigmented
or hyperpigmented, indicates an energy level that
is too high. Adjust the energy level appropriately
in increments of 0.25-0.50 j/cm2. If the results
are not acceptable, the test doses should be repeated
using different energy parameters.
Darker, more mature lesions will usually require a lower
energy density than lighter lesions. Lesions that
show evidence of textural change from prior treatment
modalities, surgical scars, recalcitrant warts or lesions
that are nearly completely faded may require slightly
higher fluences.
Documentation of the test sites either with photos or
anatomic forms is helpful during the evaluation phase.
It not only will clarify the location of the sites,
but will indicate what energy level was administered.
Photos are very helpful in determining incremental
fading between treatment sessions.
Preoperative Care
1. Patients are to
avoid sun exposure, including tanning beds and sunless
tanning creams for one month prior to and throughout the
course of the treatment.
2. No
makeup, lotions, deodarant or oil on the area to be treated.
3. EMLA
may be used as a topical anesthetic per the doctors¹ orders.
Treatment
The V-Star combines short and extended
pulse durations for therapeutic and cosmetic applications.
The short pulse durations (0.5 msec,
2 msec) deliver the standard of care for traditional therapeutic
vascular applications. 0.5 msec has been established
as the ³gold standard² for treating pediatric port wine
birthmarks.
The addition of extended pulse durations (20 msec, 40
msec) cosmetic vascular lesions are treatable with a reduction
or elimination of Purpuric response.
It is very important to remember that treatment technique
with the Cynosure laser system is different from other
flashlamp pulsed dye lasers. This is due to the
different characteristics of the individual manufacturer
beam profiles. The Cynosure beam profile is similar
to a ³top hat² with sharper edges. Other systems
offer a beam profile that is not as clearly defined, with
fuzzy edges.
The homogenous beam profile of the Cynosure laser eliminates
the need to overlap delivered pulses. The use of
overlapping pulses can cause an additive thermal effect
resulting in nonspecific thermal damage to the superficial
dermis and epidermis. Aligning the pulses adjacent
to each other in an interlocking pattern is recommended.
Overlapping of pulses should be utilized only when
treating erythematous, hypertrophic scars, nodular lesions
or recalcitrant warts. Because of the dramatic differences
between the beam profiles, the fluence for one laser should
not be used for another.
General considerations
1. Each area should
be treated only once (with the exception of some warts)
with tight interlocking, but not overlapping pulses.
2. The
handpiece should be held as perpendicular as possible
and be lightly touching the skin surface. This contact
is the point at which the laser beam is in focus.
3. Most
adult lesions can be treated without anesthesia. However,
if the lesion is large, in a sensitive area, or the patient
has a low pain threshold, or is an infant or child, consideration
should be given to make the patient comfortable.
The Cynosure SmartCool, air cooling device, is highly
recommended to be used in conjunction with the PhotoGenica
V-Star to minimize pain during treatment.
4. Laser
energy delivered with the 7 mm and 10 mm handpieces has
been shown to penetrate deeper into the tissues than the
smaller spot sizes. With a larger spot size less
scatter and more homogeneity of the laser beam occurs
with deeper penetration for the same fluences utilized
with smaller spot sizes. Histology has shown that
slightly deeper and slightly larger diameter vessels can
be coagulated with the larger handpieces.
5. When
treating telangiectasia, it is recommended to trace the
vessel with laser pulses, beginning at the end of the
vessel branch working toward the larger feeding vessel.
This will disrupt the blood flow and subsequently
shut down the offending vessels. The best result
is achieved when the entire vessel or group of vessels
is treated.
6. Patients
with darkly pigmented skin are generally less responsive
to treatment because of the competition from epidermal
melanin. These patients will generally require more
treatment sessions to reach the same degree of clearing
as lighter skin types. Test sites are highly recommended
in darker skin types.
7. It
is important to remember that improvement and clearance
of vascular lesions such as Port Wine Birthmarks is gradual
and may require five to ten treatments. Although
determining the point of maximum clearing can be difficult,
treatments should continue as long as each results in
an increment of improvement.
8. The
treatment of striae can improve the appearance of most
stretch marks. Although the mechanism is unknown,
increased elastin formation induced by the laser at the
treated sites is likely responsible for the improvement.
Expected Outcomes
1. The anticipated
tissue response is a red blotchy response initially, followed
by a purpuric response within a few seconds to a few minutes.
Purpura is a dark purple discoloration caused by
capillary hemorrhage from the laser impact. The
most severe degree of purpuric darkening occurs within
24 hours post treatment and begins to fade after the first
48 hours. In general, purpura will dissipate within seven
to ten days on the face. It diminishes more slowly
on the trunk and extremities.
2. When
treating vascular lesions such a Port Wine Birthmarks
or Rosacea, an Erythematous or reddened tissue response
from the laser impacts is expected. This tissue
response makes it difficult to distinguish the treatment
site from the non-treated areas. To eliminate this
anticipated problem, either trace the area to be treated
with laser pulses and fill in toward the center of the
lesion, or, define the demarcated areas of the lesion
with a skin scribe. Use caution not to lase the
ink, as it will absorb laser energy.
3. The
clinical endpoint of treatment for striae is a mild erythema
and/or purpura often accompanied by transient hyperpigmentation.
Postoperative Care
1. Decreased purpura
will result when using long pulse durations (20 msec,
40 msec).
2. Purpura
may be evident and it may get darker 24-48 hours after
treatment.
3. Purpura
usually lasts approximately 10 days when evident.
4. No
rubbing and/or scratching treated area.
5. No
swimming or jacuzzi while discoloration is present.
6. Apply
antibiotic ointment 2 times a day while discoloration
is present.
7. No
shaving area if crusting is present.
8. No
picking crusted area. Keep moist and let it fall
off on its own.
9. Applying
make-up is o.k. if no crusting is present.
10. Discomfort
may be relieved by ice packs or Tylenol.
11. Patient
is to contact Physician if there is any indication of
infection (redness, tenderness or pus).
12. No
sun exposure: use a sunblock with a SPF of 30 when
area is exposed to the sun.
Adverse Effects
Complications, though rare, can occur and should be discussed
and understood. The patient must understand the
importance of the pre and post care instructions and that
failure to comply may increase the probability of complications.
Hypopigmentation
Hypopigmentation is represented by a decreased
amount of pigment in the treated area as compared to the
untreated, surrounding tissue. It is more commonly
seen in dark skinned individuals, but may also occur with
sun exposure on facial areas and after treatment of vascular
lesions on the leg. Persistent hypopigmentation
is more common on the neck, legs and chest.
Hyperpigmentation
Hyperpigmentation is represented by an increased
amount of pigment in the treated area as compared to the
untreated, surrounding tissue. It may be caused
by extravasation of erythrocytes through the laser damaged
vessels. More commonly seen in post sclerosis patients,
hyperpigmentation may also occur in patients treated with
too high a fluence. The value of performing test
sites prior to treatment is imperative to preventing this
type of complication. Pigmentation changes are usually transient and last an average of 6 months.
Punctate Depressions
Small minute spots of depression may occur post
laser treatment if laser fluences are too high or if a
significant amount of overlapping technique was utilized
during treatment. In most cases, punctate depressions
will fill in naturally during the healing phase.
Atrophic Changes
Textural surface changes have occasionally been
noted in patients that have not been compliant with post-treatment
skin care instructions. Surface changes have usually
involved small areas of excoriation. Incidence of
Hypertrophic scarring has never been reported.
Blistering
This may be an indication of sun exposure or too
high a fluence for the skin type. The blistered
area should be treated with antibiotic ointment 2 times
a day. The area should not be picked, as this may result
in a scar.
Treatment Parameters
Lesion Spot
Size Parameters
0.5 msec
(Purpuric
Doses) Parameters
2 msec
(Purpuric Doses) Tx
Interval
Angiokeratoma to 10 mm 5.5
- 6.0 J/cm2 Four
to six weeks
Cherry Angioma to 10 mm 6.0
- 8.0 J/cm2 Four
to six weeks
Erythematous , Hypertrophic, and Keloid Scars 7
mm 3.0 - 6.0 J/cm2 8
- 12 J/cm2 Four to six weeks
Facial Rejuvenation 7 mm 2.0
- 4.5 J/cm2 Two
to three weeks
Hemangioma To 7 mm
10 mm 4.0 - 5.0 J/cm2
3.5 - 4.0 J/cm2 Two
to three weeks
Piokiloderma of Civatte To 7 mm
10 mm 4.0 - 5.0 J/cm2
3.0 J/cm2 Four
to six weeks Overlap pulses 25%
Port Wine Birthmark 7 mm (Pediatric)
7 mm (Adult)
10 mm (Pediatric)
4.5 - 6.0 J/cm2
5.0 - 6.5 J/cm2
3.0 - 4.5 J/cm2 4.5 - 6.0 J/cm2
5.0 - 6.5 J/cm2
3.0 - 4.5 J/cm2 8 - 12 weeks
Lesion Spot Size Parameters
0.5 msec
(Purpuric Doses) Parameters
2 msec
(Purpuric Doses) Tx
Interval
Pyogenic Granuloma 5 mm
6.5 - 7.5 J/cm2 Three
to four weeks
Rosacea To 7 mm
10 mm 5.0 - 7.0 J/cm2
3.0 - 3.5 J/cm2 Three
to four weeks
Spider Angioma To 7 mm
5.5 - 6.0 J/cm2 Three
to four weeks
Striae To 10 mm 3
J/cm2 Six to
24 weeks
Telangiectasia, Leg 3x5 mm
7 mm
10 mm 7.0 - 7.5 J/cm2
4.0 - 5.0 J/cm2
3.0 - 3.5 J/cm2 12 - 16 J/cm2
12 - 16 J/cm2
12 - 16 J/cm2 Four to six weeks
Telangiectasia, Face 3x5 mm
7 mm
10 mm 7.0 - 7.5 J/cm2
4.0 - 5.0 J/cm2
3.0 - 3.5 J/cm2 5.5 - 7.5 J/cm2
5.5 - 7.5 J/cm2
5.5 - 7.5 J/cm2 Four to six weeks
Venous Lakes To 7 mm 6.5
to 7.0 J/cm2 Four
to six weeks
Warts 7 mm 7.0 to
9.0 J/cm2 8 - 12 J/cm2 Three
weeks
Extended Pulsrations (20 & 40 msec)
e Du
The following provides suggested guidelines for treatment
with extended pulse durations. At this time, treatment
methods to take best advantage of extended pulse widths
are under development. In the mean time, standard methods
of test spots and clinical judgment should be used to
determine treatment plans on a case-by-case basis. Once
effective, accurate, and repeatable methods confirmed,
an updated manual will be provided to system owners.
The 20 and 40-msec pulse durations are designed to increase
the purpuric threshold, allowing greater treatment selectivity,
with less risk and a shorter duration of purpura.
Reduced purpura treatment may prove less effective than
purpuric treatment, necessitating additional treatments
to achieve a desirable endpoint.
The purpuric threshold in normal skin, in conjunction
with SmartCool air-cooling, has been estimated at:
0.5-msec: 5.5 ± 2.5 j/cm2
2-msec: 8.0 ± 2.0 j/cm2
20-msec: 10± 1.5 j/cm2
40-msec: 12± 1.5 j/cm2
Without air-cooling, the purpruic threshold is approximately
one to two joules per cm2 lower than the values listed
above.
As always, the use of test spots is strongly recommended.
The above threshold values provide a guideline for test
spots. Extended pulse durations can produce a delayed
purpuric response. It is suggested that clinicians wait
approximately 30 minutes following test spots to determine
threshold.
Minimal or non-purpuric treatment should be done approximately
1 or more joules per cm2 below the purpuric threshold.
Initial reports suggest that 2 j/cm2 below threshold may
not produce purpura when multiple passes are employed.
If multiple passes are used, they should be limited to
not more than three passes in a given treatment session.
The desired treatment response is variable and may present
as deepening of lesion color from bright red to maroon
(indicating intra-vascular purpura), lesion disappearance,
or possibly no visible change.
Lesions that do not disappear immediately may fade over
three to four weeks. Because of delayed therapeutic response,
additional treatments should be scheduled at a minimum
of three-week intervals.
Treatment Summary
The above treatment parameters provide general guidelines
for treatment. However, it is more important to monitor
the tissue response than to depend on the fluence settings
of the laser. Tissue graying, immediate blistering, blackening,
or punctate bleeding (except in the treatment of warts)
at the site of treatment are all indications that laser
fluence is too high. Conversely, for short pulse treatment
(0.5 and 2 msec), if the site does not exhibit purpura,
exhibits purpura which fades rapidly, or does not exhibit
an immediate lightening of the lesion, the fluence may
be too low for adequate treatment.
Extended pulsewidth settings (20 and 40 msec) require
higher fluences for acceptable clinical response. Treatment
with the extended pulsewidths may not cause a purpuric
response. Thus clearance, immediate lightening of the
lesion, or the appearance of erythema should be the guides
used to determine adequate treatment.
Treatment Forms
V-Star Skin Care Instructions
Precautions to
take before your laser treatment:
1.
No sun exposure,
including tanning beds and sunless tanning cream. Sun
exposure decreases the effectiveness of the laser treatment
and can increase the chance of post treatment complications.
2. Apply
a sunblock with SPF 30 whenever the area being treated
is exposed to the sun.
3. No
makeup, creams, or oils should be applied immediately
prior to treatment.
Precautions to take following your laser treatment:
1. Treat
the area delicately. Do not rub, scratch or pick
at the treated area while discoloration is present.
2. Avoid
swimming, hot tubs or strenuous exercise while discoloration
is present.
3. Do
not shave the area if crusting or blistering is present.
4. If
makeup is allowed, it must be applied and removed delicately.
Excess rubbing can open the area and increase the
chance of scarring.
5. Discomfort,
such as swelling or redness (lasting from a few hours
to a couple of days), can be relieved with Tylenol or
ice packs.
6. Apply___________________ointment
to the treated area______times a day while the discoloration
or crusting is present.
7. Please
contact the office immediately if the treated area becomes
tender and shows signs of infection (pus).
Informed Consent
Procedure
Consent
Treatment with the PhotoGenica V-Star Laser
Description
Of Treatment
An appropriate
treatment for is laser treatment using the pulsed dye laser. The laser,
which will be used, has been cleared for distribution
by the FDA for this use, and lasers like this one have
been in clinical use for several years. The overall goal
is to provide satisfactory treatment for the reduction
or elimination of .
The laser that will be used is the PhotoGenica V-Star
by Cynosure Inc.
Procedure
A brief medical history will be taken and an examination
of your skin will be performed.
For the last two weeks before treatment, you will be told
to avoid sun exposure and tanning beds. If you are obviously
tanned you should not be treated. If you have a history
of herpes, medications to reduce the risk of an outbreak
will be prescribed for one week.
On the day of the treatment, you may be required to wear
comfortable clothes and shoes. You may be asked to remove
eye glasses or jewelry you may be wearing. You may be
asked to lay on an examination table. A label or
marked may be placed over the area to be treated. This
area will be photographed.
You will be asked to wear special eye goggles to protect
your eyes against possible accidental exposure to laser
light. The area(s) of the skin will be exposed to various
doses of light from the laser system, and will be photographed
again. If the area is not anesthetized, you may experience
discomfort from the laser exposure, which has been described
as the sensation of being ³snapped with a rubber band".
Bruising, called purpura may occur and will fade within
2 or three weeks. Local swelling, crusting and redness
may also result from the exposure. You will care for the
skin area(s) gently cleaning daily with gentle, antibacterial
cleanser and applying sunscreen with an SPF of 15.
You will avoid picking or scratching the area, and you
will also avoid sun exposure and tanning beds, which can
cause skin to darken and appear blotchy. You will avoid
contact sports during healing, or if area appears bruised,
blistered, or scabbed.
The course of treatments may a number of treatments, occurring
at three to six week intervals. Following treatment, you
will then return for evaluation within a time determined
by the physician. The actual treatment time and number
of treatments will be dependent on condition being treated.
Each treatment may take up to 90 minutes. There may be
multiple follow-up visits. Each follow up visit may take
up to 30 minutes depending on the size of the treated
area.
After Care Instructions
For one week after treatment, you will be asked to
follow the care instructions listed below, to minimize
the risk of complications from this procedure. Please
note that your physician may choose to provide alternative
care instructions.
… Wash gently with soap and water
… Apply ointment (suggested by
physician) to keep the skin well moisten
… Tylenol is suggested to control
pain as needed
… No shaving over the treated
area
… Avoid all sun exposure and tanning
beds if the treated area appears irritated.
Initial studies have found that tanned skin is more likely
to blister during this procedure.
… Apply a broad spectrum UVA/UVB sunscreen, with
a SPF of 15 or greater, daily for at least 6 months.
… No contact sports during the healing (bruised)
phase
Risks and Discomforts
There is a risk of eye damage from lasers, which will
be taken care of by wearing protective goggles during
laser use. The laser exposed sites may be swollen, painful,
itchy, and may blister, or ooze fluid. The discomfort
is usually mild and fades over a few minutes to several
days. There is a risk of infection wherever the skin is
wounded, which is why you must clean and care for the
treated area as directed. Infection is rare when this
is done. When there is no infection and picking is avoided,
the risk of scarring from these lasers is low. Other risks
include white spots, which are usually infrequent and
short lived, but which can be permanent. There could be
possible loss of tanning ability in the treated area.
Occasionally, brown/gray area dark area may occur at the
sites of the laser exposure, especially if you expose
the skin to sunlight while is healing. These occur rarely,
but can be unsightly and can last for months to a year
or more.
There is a possibility that you may have local anesthetic
prior to treatment that may cause and allergic reaction.
This reaction could include itching or burning, and swelling
of the area, or could be more severe, including breathing
difficulty. There is also the possibility of infection
in the treated area.
If you know that you are HIV positive, you should inform
the staff . This is to decrease your risk of possible
complications that may arise from laser treatment. An
HIV test is not required.
Alternatives to Treatment
Alternate treatments for photodamage include .
Confidentiality
Medical information associated with treatment will
become part of your medical record, and will be stored
in the doctor¹s file under restricted access.
Contact Person / Physician
If you have any questions about this treatment, or
treatment related injury, please contact __________________
or his/her associates at ___________________________.
Consent
Doctor¹s Signature
I have explained to _____________________________
the purpose of the research, the procedures required,
and the possible risks and benefits to the best of my
ability.
_________________________ ___________________
(Doctor)
(Date)
Patient Signature
I confirm that ________________________ has explained
to me the purpose of the treatment, the procedures I will
undergo and the possible risks and discomforts as well
as benefits that I may experience. Alternatives to this
treatment have been discussed. I will receive a copy of
this consent form. I have read and understand the consent
form. Therefore, I voluntarily agree to pursue this course
of treatment.
_______________________________
Patient¹s Name (Print)
__________________________________ _____________________
Patient¹s Signature (Date)
