Laser therapy of leg vein malformations such
as varicose veins is one of the most sought after
cosmetic corrections nowadays. Its popularity
has been on the rise since the development of
safer and surer techniques and results. This
has been possible with the recent developments
in deep-reaching, near-infrared wavelengths with
millisecond pulse periods and protective skin-cooling
procedures. However, laser therapy is mainly
effective for small sized (less than 1 mm) and
superficial leg veins. Leg veins with are larger,
thicker, deeper, with high hydrostatic pressures
or consisting of assorted blood vessels types
cannot be easily corrected with lasers. Here
is an overview of the technique, types and advancements
in laser therapy of leg veins.
Ther laser procedure involved in leg vein therapy
Selective photothermolysis is the process involved
in laser therapy. This can be defined as the
targeted thermal damage of pigmented tissues
by selectively assimilated radiation. The effectiveness
of selective photothermolysis is dependent on
the following underlying factors:
Wavelength
In selective photothermolysis, the laser wavelength
should be such so as to enable the target tissues
to selectively absorb the rays up to a sufficient
depth to reach the target site. The 532-nm KTP
lasers, 585-to 595-nm pulsed dye lasers and IPL
devices (500-1100 nm) are suitable for tissue
depths less than 1.0 mm.
Near infrared wavelengths such as the alexandrite
(755 nm), diode (800 nm, 940 nm) and neody-nium:yittrium-aluminum-garnet
(Nd:YAG, 1064 nm) lasers have also proved beneficial
for leg veins.
Pulse duration
This means the period of exposure to the laser
radiation should ideally not be greater than
the time required for the target tissue to cool
down and relax. This time is called the ‘thermal
damage time’ and is a non-uniform process,
since the absorption of radiation is also non-uniform.
Fluence or energy density
This must be sufficient to achieve a temperature
suitable to damage the target tissues. If the
correct fluence is used its absorption generates
the suitable heat that enables the target tissue
to retain it and speedily dissipate it, which
is the process which triggers off the selective
damage. The selective damage by heating is made
possible when fluence or energy accumulates at
a greater speed than the cooling rate of the
target tissue.
Laser beam diameter
There are two aspects of beam diameter:
- Larger beam diameters ensure greater penetration
of heat in larger, deeper blood vessels. However,
it could increase the side effects, especially
in case of 1064-nm lasers. Hence, it is best
to match beam diameter to the vessel diameter.
It ensures optimum absorption of radiation
and minimum damage to the surrounding structures.
- Longer
spot size minimizes the diffusion of the
ray and hence improves the degree of target
tissue access.
Skin cooling
Cooling of the epidermis is essential in laser
therapy for leg veins, since it involves very
strong radiation, which may cause epidermal injury.
Epidermal cooling ensures its protection and
also improves its effectiveness by allowing the
use of higher fleunces. The various cooling options
are:
- Contact cooling
with a sapphire window or copper plate
- Cryogen
spray cooling
- Convection air cooling
- Cooling with aluminum
rollers or cold gels
Number of laser sessions
After laser therapy, there are certain effects
on the optical properties of blood, caused by
the heating of the blood vessel. As a result,
there is also a change in blood absorption capacity
after a laser application. Hence, it is best
to use a second laser pulse at lower fluences
to reduce side effects. The other way to minimize
side effects and discomfort is to first use a
pulse with a strongly assimilated wavelength
and then another pulse with a more incisive wavelength
administered at sub threshold fluences.
Keeping in mind the above factors, these are
the laser options applicable in varicose leg
vein treatment:
Long pulsed alexandrite lasers
The properties of this laser associated with
leg vein treatment are:
- Wavelength of 755 nm
- Penetration capacity
of 2 to 3 mm
- Best pulse extent for leg
veins is 3 to 20 ms
- Side effects include,
purpura, hyperpigmentation and rarely hypopigmentation
- Cryogen
spray cooling helps lessen treatment discomfort
and allows epidermally safe
use of fluences up to 80 J/cm2
- Safe
for leg veins in skin phototypes I-III and
without any suntan
- Most effective in vessels
with 0.4 mm to 2.0 mm diameter
- Leg telangiectasia
requires higher fluences and proper skin
cooling
Diode lasers
The features of a diode laser in leg vein correction
are:
- Wavelengths of 800 nm, 810 nm, and 940 nm
with 5-to 250-millisecond pulse durations is
best for leg telangiectasia and reticular veins
- Larger
veins require longer wavelengths and pulse
durations
- Discomfort is reasonable to acute
- Ice packs
are a good way to ensure epidermal cooling
- Side
effects include temporary hyperpigmentation
and hypopigmentation
- Follow-ups improve
effects
- Takes 6 months to a year for
complete clearance
- Best for patients with
phototypes I-IV and no suntan
- No safety
clearance for treatment of darker pigmented
skin as of
now
- The sapphire chilled tip
on the 800-nm diode lasers
should
be well
compressed
during a laser
pulse session to guarantee proper
epidermal cooling.
Pulsed neodynium: yittrium-aluminium-garnet
(ND:YAG)
lasers
Here are the features of this kind of laser
applicable for leg vein treatment:
- Millisecond-domain 1064-nm lasers is effective
in the treatment of reticular blue veins
and bigger telangiectasia
- Skin cooling mandatory
to avoid epidermal
injury. It also works as an analgesic
- Application
of similar wavelengths to bigger vessels
may cause considerable pain
- Cryogen spray-assisted
1064 nm Nd:YAG laser are ideally safe for
the correction
of 0.3
to 3 mm leg veins
- The superlong-pulse
810-nm diode laser shows inconsistent effects
- The
3-millisecond 755-nm alexandrite laser at
fluences of 60 to 70 J/cm2
and an 8-mm spot
is also effective but shows more
side effects
- The 1064-nm wavelength is
safe for type V skin
- The 810-nm wavelength
at very long pulse widths of 400 to 1000
milliseconds
is safe
for type IV and moderately
for type V skin
- 755 nm wavelengths are good
for the type I-III skin with
no sun
tan
