Laser application in dermatology and cosmetology field is
considered new. Clinical and practical applications of lasers are
growing up in the different research and specialized centers. Few years ago,
laser was perceived by many in the field of dermatology as a machine
searching for a disease.
Lasers have been used in dermatology for
more than 20 years. The first lasers used were the Ruby and Argon
lasers, and a great deal of experience has been obtained
particularly with the latter. The Argon laser has been used
predominantly in the treatment of cutaneous vascular lesions and the
CO2 laser both as a cutting and ablating tool.
Recently due to better understanding and modifications of the new
lasers especially the computerized ones, lasers are considered an
indispensable tool for the dermatologist. Different skin lesions
were hardly to be treated and not efficiently before laser.
Certain types of lasers such as C02 laser is of great help to the
dermatologist and are considered as "working horse" in
Although different lasers are available now with different
applications for skin resurfacing, pigment treatment, vascular and
hair removal, yet the use of laser should be monitored for selected
cases due to the higher, expensive cost of treatment besides other
factors which may be not accepted by patients.
Usually we are faced by many patients who are afraid from laser
surgery due to their belief that laser will cause cancer. In spite
that we try to convince them that laser is nothing but light and it
is used in delicate branches as ophthalmology, yet others are still
and will not be convinced.
Meanwhile, Goldman, who first used a laser as a surgical tool
warns "If you don't need a laser, don't use one."
BASICS IN LASER THERAPY
A laser is a device that generates an intense beam of light. The
term "LASER" denotes Light Amplification by
Emission of Radiation.
Light is part of the spectrum of the electromagnetic radiation.
Under certain conditions light exhibits the characteristics of a
All effects of light including laser light on skin begin with the
absorption of electromagnetic radiation (EMR). EMR is an
important form of energy that
exhibits both wave and practical properties
because the energy of light is carried through the photons.
Whenever a photon is absorbed some movement or
separation of charged matter occurs in the cells and the energy
carried in the photon is invested in excitation of the charges .
Excitation and absorption of the energy is the basic of
photobiological effects and laser application in treatment .
There are important data concerning light used in
laser treatment . These include the following:
The wavelength : is defined as the distance
between the crests of each wave and that determines the functional
properties of the laser energy. Electromagnetic radiation with long
wavelengths, measured in meters, is commonly used for radio and
Wavelengths in the 0.4-0.7um range form the
visible light of the spectrum. Ultraviolet rays, X-rays and gamma
are forms of electromagnetic radiation with the wavelengths shorter
than the visible light.
Is the height of the wave with the maximum
displacement from the zero position .
Is the number of waves passing in a given point
per second and is expressed in cycles per second. The shorter the
wavelength, the higher the frequency, and the higher is the energy.
This is a constant and is equal to 186000 miles
Surgical lasers fall between the longest and the
shortest wavelengths, in the infrared and visible as well as the
ultraviolet portions of the electromagnetic spectrum.
Several lasers are commonly used in medicine. The
type of laser depends on the active medium used. These may be C02 as
in the Carbon dioxide laser, Ruby, in ruby laser, copper as in
copper vapor laser and special dyes as in dye
lasers. The most commonly used medical lasers
are, the carbon dioxide, ruby, argon, krypton, YAG and Excimer.
The components of laser system are:
Power source: pumps energy into the
lazing medium. The power pumping energy is related to the
composition of the medium in the laser. The power source in lasers
may be electrical as in Argon and carbon dioxide or flash lamps as
in pulsed dye laser.
Lasing cavity: which is a tube with
mirrors placed at each end where amplification of stimulated
emissions of radiation occurs. Photons traveling the length of the
tube are reflected back through the medium. Each time the beam
reflects back and forth or resonates through the axis of the
medium, more atoms are stimulated to release photons, and the
laser effect is amplified. The end of the mirrors has a small
opening allowing a minute part of the laser light to be
A wave guide: The laser light is invisible
and therefore a fibro- optic HeNe low beam is used to guide the
laser light towards the desired tissue to be treated.
capacity to do work and is usually calculated as power multiplied by
time of laser light exposed on the skin surface. The unit of
measurement is a joule.
Power: is the rate of flow of energy. This is
calculated as energy divided by the time of application. The unit of
measurement is the watt. One watt equals one joule per second.
Power density: is
the rate of energy delivery per unit of target tissue area. This is
expressed in watts per square centimeter. Power density is
determined by the power divided by the surface area of the beam or
the spot size. It should be noted that increase in the power output
vaporizes tissues rapidly and reduction in the spot size will
increase in the energy and accelerates more tissue interaction.
Fluence: is the energy density and calculated
as the total energy divided by the cross sectional area of the beam.
It is expressed as joules per square
centimeter. It is calculated as the laser power
multiplied by time of exposure over an area of spot size in cm2. If
the heat is deposited at a rate faster than the thermal relaxation
time, there will be minimal conduction of heat to the surrounding
Spot size: Large spot size allows for
smoother, more uniform vaporization of tissues.
The spot size is controlled by focusing or
defocusing of the lenses. Simply by moving the hand piece towards
and near the skin decreases the spot size, or away from the target
increases the spot size. The smaller the spot size the greater
tendency to create uneven ridges, furrows and bleeding. Larger spot
size causes decrease in peripheral thermal damage.
Thermal relaxation time
This is the time
required for the heated tissues to loose some of its heat through diffusion. It is the time needed
for adjacent tissue to cool during laser surgery. This is very
important which has a direct relation to tissue destruction.
PROPERTIES OF LASER LIGHT
Laser light has three special qualities that
distinguish, it from the conventional light source .
Collimated: means that laser light
travels parallel in a single direction with very little divergence
even for a long distance and therefore there is minimal loss of
power along the beam . A laser beam is a 1000 times brighter than
the daylight and is brighter than the sunlight.
Monochromatic: consists of one color
or wavelength and thus the laser beam is very pure. In contrast,
white light from a regular light bulb involves the spontaneous
emission of photons of many wavelengths or colors, traveling in
various directions and emitting diffuse light.
Coherent: means all of the light waves move
parallel in phase together in both time and space. Ordinary light
from a lamp consists of a mixture of wavelengths radiating in
different directions and out of phase . It is in a laser term
considered as incoherent.
MODES OF ACTION OF LASER LIGHT
This depends mainly on the absorption of a photon
by a chromophore or the target tissue such as melanin pigment, water
or hemoglobin. The photon surrenders its energy to the chromophore
and then ceases to exist where the energy is converted into heat,
which is dissipated to the neighboring tissue, by conduction or
radiation. In the cells most proteins , DNA, RNA, membranes and
their integral structures start to melt at temperature more than 40
degree centigrade where tissue becomes coagulated .
The severity of coagulation or tissue
denaturation depends on both the fluence and time of exposure.
Fig. 444. Skin penetration of
light of different lasers
HUMAN SKIN AND LASER INTERACTION
The nature of interaction of all laser light with
biological tissue can be described in terms of:
is always a degree of reflection of laser light from the epidermis.
laser light is transmitted through tissues to their target.
occurs after the laser light is transmitted and passing the
epidermis to deeper tissues.
occurs by the target tissue of the specific type of laser. Absorbed
laser light may cause tissue coagulation or vaporization.
Characteristically, laser light searches for its target such as
pigment, hemoglobin or water.
related to the thermal effect .The conversion of laser energy into
heat causes coagulation, sealing or cautary with minimal necrosis
occurs with temperature above 45 degree centigrade.
occurs with temperature over 100 degree centigrade , particularly
with rapid heat transfer from the laser light to the tissues. This
will lead to boiling of cellular fluid and complete destruction of
cellular protein and the cell itself. The fume of this vaporized
tissue causes small particles which is about one micron . It is of
prime importance to use special laser mask during skin resurfacing
especially viral lesions such as warts where inhalation of these
fumes containing the viral elements may cause serious complications
.The laser mask should have special specification to filter
particles less than one micron .
|Temperature is directly related to the average
kinetic excitation molecules. As temperatures are raised ranging
from 40-100 degree centigrade most proteins, DNA, RNA, membranes and
their integral structures start to melt denature and coagulate.
Fig. 445. Laser absorption and Tissue penetration
In laser tissue interaction, thermal coagulation
causes cell necrosis, homeostasis, welding, ceiling of nerve endings
and gross alteration of the extracellular matrix. Thermal
coagulation is also a burn.
Carbon dioxide lasers depend on evaporation of
tissue water, which is the laser chromophore in these types of
lasers. Other lasers target is the skin pigment such as pigmented
cells, blood vessels and tattoo particles. Tissue damage depends
mainly on the rate of energy deposition in the target.
The fundamental processes govern all interactions
of light with the tissue target are heat absorption or scattering.
Heat is absorbed by the chromophore (melanin pigment. water, blood
vessels) where each chromophore has a selective wavelength
absorption .The absorption coefficient depends on the concentration
of the chromophore present in the lazed tissue.
first pigment that light encounters as it enters the skin. Melanin
protects the skin from excessive sunlight, particularly the UV by
absorption harmful wavelengths. This physical property of melanin
makes it either aid or interferes with laser surgery depending on
the type of lesion treated. Melanin occurs mainly in the epidermis
and hair follicles absorb broadly across the optical spectrum.
Hemoglobin: The iron containing pigment that
makes blood red, blocks a large amount of light transmission into
tissues. Hemoglobin has three absorption peaks: Blue (415nm), Green
(540nm) and the Yellow (577nm). The optimum absorption is between
514-590 nm. Blood absorption is dominated by oxyhemoglobin and
reduced hemoglobin absorption that exhibits strong bands in the UV,
blue, green and yellow bands. The 577 nm (yellow) absorption band of
oxyhemoglobin was chosen for targeting superficial micro vessels by
selective photo thermolysis .The blue band (420 nm) or higher band
900nm penetrates more deep and can affect deeper target tissues.
Scattering: Scattering is the third important
factor in tissue interaction during laser therapy. The target, may
absorb light entering the skin whether scattered or reflected. Most
light entering the tissue is scattered by a very complete
interaction with water. lipids and cellular membrane. Scattering is
greater for short wavelengths of visible light.
Scattered light is ultimately absorbed with the
subsequent release of heat. Scattering is one mechanism whereby,
heat is lost from the lesion being treated to be deposited in
non-target tissue. Scattering is also the reason that the outline of
bones cannot be seen when the hand is trans- illuminated.
These three factors, melanin, hemoglobin and
scattering are the basics in laser application in dermatology and
EFFECT OF LASER LIGHT ON THE SKIN LESIONS
The epidermis is
100 um thick and is very
susceptible to laser energy. It is almost universally damaged during
laser surgery with visible light wavelengths unless adequately
pre-cooled. The upper dermis is 400um thick and contains c'llary loops in the pegs supplied by the superficial arteriolar
plexus. which is supplied from arteries in the lower dermis.
The normal superficial plexus consists of 50um vessels and is a principle
factor in skin coloration. The lower dermis is 400um consists of the supporting
structures of the sweat glands, follicular structures and larger vessels.
When laser is directed to skin, light may
penetrate the skin surface, absorbed by the target tissue, reflected
There are three major factors, all-important in
laser therapy, which keep tissue from being more transparent than it
is. These are the targets for laser. Different lasers are
principally depend on these factors, which are: the pigment melanin,
hemoglobin and water.
When treating a pigmented lesion, the light
absorption characteristics of melanin are most important. Melanin is
the target pigment or chromophore and is heated by absorption of
the laser light to the point where the lesion is destroyed. The
surgeon chooses a wavelength that is well absorbed by melanin.
Generally a wavelength in the Blue/Green range is needed. Blue has
higher absorption (but more scattering) than the green. Because of
the increase of likelihood of scarring with the blue wavelengths,
the typical choice for a pigmented lesion would be the green.
Vascular lesions treatment
Hemoglobin is the pigment target or chromophore
for laser light. Any unwanted absorption in the skin by melanin
would tend to heat non-targeted or non vascular tissue above or near
the vascular lesion. Ideally the surgeon should be able to beam the
light through the non vascular, melanin containing surface tissue
without damage from their melanin absorption or scatter, and destroy
vascular tissues beneath. He would choose a wavelength that is
highly absorbed by hemoglobin and scatters minimally. Yellow
wavelength : is the ideal and fits that most closely.
Yellow light has minimal scatter and decreases
absorption in melanin compared to green or blue. Longer wavelengths
such as orange, red are not well absorbed by hemoglobin or melanin.
Complications of laser surgery
The complications which may be faced during laser
In vascular lesions treatment, scarring may occur
if too much light energy is absorbed by he epidermis and
perivascular dermis below the reticular layer of the skin. If the
epidermis is damaged it can regenerate without scaring, while damage
of the dermis may cause hypertrophic scarring. This is the worst
complication when treating a vascular lesion as port wine stain with
the use of Blue/Green wavelengths. especially in young
children. Other complications besides hypertrophic scarring are
hypopigmentation, hyper pigmentation and texture changes.
TYPES OF LASERS USED IN DERMATOLOGY
CARBON DIOXIDE LASER
is the most widely, precise tool used in dermatology, cosmetology
and general surgery. The laser medium is mixture of carbon dioxide.
nitrogen and helium gases, usually excited by direct current
electricity . The C02 laser emits a continuous beam having a
wavelength is 10600 nm , in the midinfrared portion of the
electromagnetic spectrum. The beam of C02 laser is invisible and
therefore a lowpower visible beam is used to provide an aiming dot
for the surgeon to guide and direct the beam to the desired target .
Laser energy passes through an articulated arm
and focusing lens or through a hollow wave guided . The tissue
target for this type of laser is water, where light is absorbed by
biologic tissues causing destruction by rapidly heating and
vaporization of the intercellular water. The strong absorption of
the laser light by water causes tissue destruction "What you
see during operation is what you get of the effect on human tissue
The output power may exceed 100 watts in the
continuous operation and 50 watts when using the pulsed operation .
The factors affecting tissue destruction by laser
is the power reaching the tissue , spot size and the thermal
relaxation time ( which is the time between heating of tissues by
the laser beam and the time of cooling of tissues). C O 2 lasers are
now provided by computerized devices that make their use safer and
much easier for the users . These computerized devices are
programmed in a more simple way for use either for skin resurfacing,
surgical cutting or simple ablation of the skin surface. The surgeon
just uses the parameters according to the case he has to treat. The
laser power and spot sizes are all adjusted automatically.
Q-SWITCHED RUBY LASER
This is the first laser used by Dr. Goldman in
1965 for treatment of pigmented skin lesions and tattoos.
Ruby laser (694 nm) of the Q-switched type can
remove blue and black tattoo pigment. This type of laser can remove
tattoos with minimal scarring and without anesthesia. Several
sessions may be needed to remove pigmented lesions by the Qswitched
Ruby laser. Different successful results depend also on the type of
Nd:YAG is another type of Q-switched laser with
longer wavelength (1064 nm) and can be used to remove tattoos and
pigmented skin lesions.
The laser medium is neodymium-doped yttrium
aluminum garnet crystal. This type is used in ophthalmology.
COPPER VAPOR LASERS
Several Metal lasers have been introduced
recently which depend on a metal lazing medium heated above the
boiling point to the gaseous state. Two different lights with two
different wavelengths are emitted from this type of laser. The GREEN
light at 511 nm is used for treatment of benign pigmentary lesions
such as Cafe au lait spots , lentigo ,and benign dermal tumors . The
YELLOW with a wavelength of 578nm is used for treatment of vascular
lesions such as telengectasia.
ARGON ION LASER
The argon ion laser emits a beam of 488-514 nm is
a blue green beam found in the visible portion of the
electromagnetic spectrum . The excitation medium is the ionized
argon gas in a sealed laser tube , which is excited by a direct
current electrical discharge . This type is used in ophthalmology
and in dermatology for treatment of haemangiomas .
The laser medium is holmium, emitting laser beam
with a wavelength of (214nm )and excited by a flash lamp. This type
is used for orthopedic treatment of torn meniscus, synovial disease
, and articular degeneration .
These types emit beam within the ultraviolet
portion of the
spectrum from (193_351 nm ). These lasers are used in cardiovascular
investigations to remove vascular plaques and in ophthalmology.
Laser emits an intense beam
of electro-magnetic radiation
that can easily cause irreversible damage to tissues, particularly
ophthalmic tissue. therefore strict precautions should be taken into
consideration when using lasers . Protection of the patient , the
surgeon , the assistant is of prime importance.
The operating room
LASER safety door sign should be applied for
warning of unauthorized persons not to step into the laser area
whenever the laser is working .
It is recommended to hang eye goggles on the door
to remind each one entering the laser room during operation to put
on goggles before entering the laser room
Windows : must be covered with materials of
sufficient optical density.
Instruments used should be of special type not
reflecting laser light.
The room should not contain volatile substances
such as ether, alcohol .
Water basin should be available.
Gauze used should be moistened with water to
prevent inflammation by the laser light.
- Safety measures for the patient:
Special glasses should be used . It should be
noted that different lasers have different glasses, which is special
for that type of laser and can't protect from other laser light.
Eye shields: applied and cover the eyes by moist
gauze before applying the glasses.
Patient's lips: can
be protected by moist gauze. When operating in the oral cavity, care
should be taken to protect teeth and bone by using wet gauze or
other nonflammable, heat absorbing protective material.
Char can be removed by moist saline gauze , where
charred areas may reach very high temperature as laser energy
continues to be applied causing more destruction to tissues.
Certain areas to be treated may need special
precautions such as laser surgery for piles. The anal orifice should
be blocked by moisten gauze to prevent inflammable gases which may
come if there if flatus, causing severe burn to the patients.
The surgeon and the assistants should use the
special glasses for the particular laser.
NEVER look directly into the laser source or at
sites of laser reflection.
Both direct and reflected laser output can
contain enough energy to cause permanent eye injury.
anyone near the laser while it is in use without protective eyewear.
NEVER point the hand probe in any direction,
except toward the area to be treated.
Before activating a hand piece, confirm that
the tip of the probe is pointed
in safe direction.
The surgeon should be like an alert soldier who
is trying his weapon pointing that always away from his colleagues
even when he is sure that it is unloaded.
laser treatment exposures if the HeNe aiming beam is not in the
field of view.
If the HeNe beam (which is weak laser beam used
to guide the direction of the intense laser beam emitted from the
machine for surgical application) is absent, first make sure first that
the" Manual Safety Shutter" is in the open position.
hands or other objects in the path of the carbon dioxide beam.
Severe burn may occur.
NEVER discharge the laser without a target to
absorb it and without consideration giving to what lies behind the
target. Saline soaked gauze sponges or saline moist gauze or water
soaked clean gauze can be used to protect tissues.
LASER FOOT SWITCH
:only the surgeon should have
access to the laser Footswitch.
NEVER press the foot paddles unless you are
starting treatment and all safety precautions should be considered.
NEVER attempt any preventive maintenance on the laser.
NEVER use the laser in inflammable situation.
STAND BY position: keep the laser in the standby
position when you want to shift to other area or you stopped working
temporarily for any reason to prevent accidental exposure to laser
MASKS: Special masks should be used especially
when removing viral lesions to prevent inhalation of the viral
Smoke evacuator: The laser plume obscures the
operative field and is noxious to those who come into direct contact
with it . The plume should be effectively evacuated by repeated
suction by special vacuum system.
NEVER remove the laser protective covers.
NEVER operate the laser if there is any leakage
of water from the console. (Certain types of lasers contain water
NEVER operate the laser if the power cable is
faulty or the indication of the calibrating device is showing
"NO GO"(Ruby laser).
ROUTINE inspection and maintainance is very important.
Certain types of lasers contain water. The high
voltage used to excite the laser and water used for the cooling
system may cause dangerous hazards.
Proper training for the surgeon and assistants
concerning laser physics, the components and how the machine can
work is of prime importance .
Always remove the key
after switching OFF the
Ensure that the laser system is working properly
should be examined and
placed away from a heavy traffic area.
Ensure that the operator-selected beam
the beam alignment are working properly.
Ensure that the HeNe guiding beam
working before any surgical treatment.
NEVER fire the laser if the helium-neon beam is
invisible in the field.
Keep the foot switch away
from the reach of
others except the surgeon.
Keep the foot away or the machine in the
position when temporarily for any reason the surgeon wants to
inspect the treated area or doing somewhat else.
OF LASERS IN DERMATOLOGY
The uses of laser in dermatology have grown in
the recent few years and based largely on better understanding and
the modifications applied recently to different lasers.
The C02 laser can be used to vaporize or to cut
tissues. The important criteria in using C02 laser are the power
output and the spot size. The spot size can be changed either by
defocusing the beam, keeping the hand piece away from the treated
area or by focusing the beam keeping it nearer to the area .Spot
size of 2-5 mm is typically used for vaporization and the power
output is decreased to get the best surgical results when doing
Uses of Co2 Laser
Co2 laser can be used successfully to treat the
Skin resurfacing: removal acne scars, skin
wrinkles, hypertrophic lesions
of lichen planus, xanthelasma. seborrheic keratoses, psoriasis
patches with excellent results by an experienced surgeon.
Actinic cheilitis :C02 laser is the treatment of choice for
treatment of actinic cheilitis.
Fig. 446. Nevus of
Ota (Before Treatment)
Fig452. Angiofibroma of lips
Fig. 447. Nevus of Ota
(treated by Q-Switched Ruby laser)
Fig. 448. Acne Scar
treated by Co2 laser
removed by CO2 laser
Fig. 448b. Skin Resurfacing by Co2 laser
Fig.454 Acne scar
Acne scar(before Co2 laser resurfacing
Fig.456warts of the knee
Fig. 449b. Hair
Depilation by laser
Fig.455 Acne scar (same patient 455b)
treated by CO2 laser
Fig. 451. Warts treated by Co2 laser
Acne keloidalis resurfaced by Co2 laser
Fig. 451Acne keloidalis(before
Fig. 450.Tattoo Removal by
Q- switched laser
of different sizes can be easily
and effectively vaporized by C02 laser. It is recommended to use a
magnifying lens during vaporization of warts. Warts typically bubble
on evaporation . Precautions should be taken during vaporization of
warts by using a special laser mask to filter wart particles during
vaporization in order not to inhale the particles, which may cause
infection to the surgeon.
The surface of the wart is better shaved before
laser vaporization to remove the dry hyperkeratotic surface, which
requires much high energy because of its lower water content. Peri
ungual warts can be vaporized and if the lesion is extending beneath
and around the nail , the overlying nail can be evaporated to avoid
Vascular lesions: such as telengectasia,
port-wine stains, angiomas.
lesions: Epidermal nevi,
lentigines , ephelides, tattoo and pigmented labial macules.
Tattoos: can be removed by vaporization the area
with a bloodless fields. This method usually leaves scar. Other
types of lasers such as Q-switched lasers are more efficient in
removing tattoos without skin scarring .
tumors: neurofibromas, myxoid
cysts, and granuloma faciale.
Actinic keratosis and squamous cell carcinoma.
Debridement of burns.
Control of bleeding.
Cosmetic surgery: Rhinophyma, blepharoplasty, and
The patient should sign a special form to agree
about laser surgery and that he had information about that. The
patient also understands that he has to abide with instruction of
the surgeon and he accepts any complications, which may result after
The patient is instructed that there is an
erythema resulting after the operation, which may extend for one
month or more and he should keep away from direct exposure to sun
light and use exactly the medications as prescribed.
The patient should have information about the
type of the skin lesion to be treated.
The type of laser surgery to be applied.
Result of Laser Surgery:
It is very important that the surgeon should
discuss to the patient be informed that "No human being by any
device can return the treated area exactly the same to its previous
condition." The surgeon will do his best and every unexpected
situation may happen. The surgeon must not give too much hope for
the patient, meanwhile he should be honest and wise in telling the
whole story to his patient
ANESTHESIA FOR SKIN RESURFACING
EMLA cream (Astra Pharmaceutical product) is
composed of Lidocaine and Prilocaine
Emla is the most widely used anesthetic for skin
resurfacing of scars, wrinkles, actinic cheilitis and other most
skin lesions .
Emla is effective for two or three passes . Its
optimum effect is more when applied and used in the following way:
Clean the area well by moist gauze with water or
Rub the cream thoroughly.
Apply a thick layer and leave it for about one
Use the plastic cover supplied with the cream to
cover the area with the cream to have an occluded field.
Emla may be applied again 15 minutes before
surgery and cleaned before the operation. This may be needed in rare
cases for very sensitive patients and children. The effect of Emla
is on its optimum when the occluded skin shows pallor coloring.
Regional block : used for deeper resurfacing
or sensitive patients, or wide area to be treated.
9. Local infiltration of the lesions by
SKIN CARE INSTUCTIONS AFTER LASER SURGERY
The patient should be instructed to abide strictly
with the following:
Do not rub, scratch or put pressure on the
treated area until skin changes like erythema and crusting clears.
Do not apply make-up if there is severe
reaction like oozing and blistering of the treated areas.
Washing of the face gently by water may be
allowed, while swimming is postponed for 2-4 weeks.
The treated area should be kept away from
exposure to sunlight and sun blocks should be used two weeks before
and four weeks after surgery.
Post laser hyperpigmentation and scarring are
the main problems of laser surgery. To minimize post laser
hyperpigmentation the following formula can be used by the patient
two weeks before and eight weeks after laser surgery.
0.2% Retin A
This formula should be prepared in a special base
cream and should be kept in refrigerator in order not to become
darker in color.
It can be used gently twice daily. The
concentrations of the ingredients can be modified according to the
type of skin , condition of the treated area and age of the patient.
Acyclovir tablets used 5 days before the
operation in patients having history of herpes lesions.
Oral antibiotic such as Cephalosporin can be
given as a prophylactic measure.
Apply polysporin ointment.
We rise in our medical center combination of
Pufexamac and Muperacin cream ( Droxaryl & Bactropan) that
proved to have an excellent post-operative healing and minimizing er
ythema arid hyper pigmentation .
The resurfaced area can be covered by Vaseline or
vigilion dressing. The dressing is left in site for 48 hours and
then removed using only the medication without covering .
Ice bags, cold milk compresses or Pufexamac cream
(Parfenac, Droxaryl cream) can be applied several times a day to
alleviate erythema and edema.
Do not remove the Crusts.
Emollients such as (Oileatum cream ) can be used
to keep the skin moist. Washing can be permitted avoiding tissue
papers for drying of the skin. Soft cotton towels can be used.
Minimize irritation of the skin by gently drying
without rubbing , just to press gently the cotton towel to the area.
Avoid irritants to the resurfaced areas such as
perfumes or strong soaps. Mild soaps can be used such as Alpha keri
soap or white Dove soap.
Avoid direct sun exposure:
This may lead to hyperpigmentation especially in
Ablation: removal of tissue by vaporization.
Beam: a ray of light.
Divergence: increase in beam diameter with
distance from the exit aperture of laser.
Chromophore: optically active material in tissues
that can act as an absorptive target for laser (melanin, hemoglobin
Absorb: To take up matters or energy.
Absorption coefficient: Ability of light to be
Active medium: The active material in the laser.
Energy: The capacity for doing work (watts
multiplied by seconds joules).
Intensity: the power transmitted by a light
wave across a unit area perpendicular to the wave.
Power: the time rate of doing work (watt)
Power density: the power of the laser beam per
unit area (watts/cm2).
Excitation: The addition of energy to a
particle or system.
Fiberoptics: a system of flexible quartz or glass fibers with internal
reflective surfaces that pass light through thousands of glancing
Aiming beam: HeNe of low density beam used to
guide the invisible laser light to the treatment area.
Laser medium: (active medium) material used to
emit the laser light.
tem00: The lowest order mode possible , a
gaussian or bell-shaped distribution of light intensity across the
laser beam cross-section.
tem:Transverse electromagnetic mode.
Argon: gas used as a laser medium.
Coagulation: destruction of tissues by heat
without physically removing it.
Vaporization: conversion of a solid or liquid
into a vapor.
Collimation: all rays coming from laser are
parallel to each other.
Coherent radiation:same wavelengths move together
to different points.
Thermal relaxation time: The time it takes heat
to diffuse out of a structure and into surrounding structures by
thermal conduction. When pulsed duration of a laser is shorter than
the time required for heat to spread out of a target, the heat
damage will be confined to the target.
Target site: tissue that is aimed or fired
with the laser beam.
Gaussian curve: Normal statistical curve
showing a peak with even distribution on either sides.
Photocoagulation: tissue coagulation by laser
Mode : the way in which laser beam is
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- Page number in bold face
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- Paragraphs in italic type
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