Introduction to scar removal
Scars are a permanent mark left on the skin
due to wound healing. Most scars are harmless but
some scars that cause pruritus, pain, disfigurement
or are disabling need to be removed. There are
mainly three types of scars, needing removal; hypertrophic
and atrophic scars, and keloids.
The advent of lasers has led to improved treatment
of scars. Laser treatments commonly used for scar
removal for decades include continuous wave CO2,
argon, Nd: YAG and Er: YAG lasers. The choice of
laser depends on absorption characteristics of
the target, type of scar, and histories of the
scar, trauma and previous therapy.
Hypertrophic and keloids treatment
CO2, argon and Nd: YAG lasers have been used for
a long time to treat these scars. However, the
improvements were temporary and recurrences were
frequent. The CO2 laser moreover aerosolized hepatitis
B and C, and HIV, and other viruses, putting the
surgeon at risk. Use of these lasers were therefore,
Later, the vascular specific 585 nm flash-pumped
PDL was found better in treating these scars. Hypertrophic
scars, less than a year old, responded better and
needed fewer treatments, compared to older scars.
Scars in dark skinned patients also showed better
responses to treatment. Lower fluences were associated
with more rapid response and multiple treatments
with greater clinical improvements. However, no
fluence dependence was noted.
Many aspects of the scar condition show imrovements
with combined therapies. PDL combined with intralesional
corticosteoids showed reduced pruritus in one study.
Another study found increased pliability, and reduced
pruritus and sclerosis with or without steroids,
though addition of corticosteroids did show more
improvements. PDL with CO2 lasers, showed better
results in nonerythemous and minimally hypertrophic
Atrophic scars are more difficult to treat. Traditional
methods used various means to mask the scars but
the side effects limited their use. Today, lasers
offer a better alternative. Resurfacing may be
done by ablative or non-ablative laser systems.
Ablative resurfacing of atrophic scars
Atrophic scars are treated by CO2 and Er: YAG
CO2 laser: The latest laser technology allows
a more selective ablation of the water containing
tissues, resulting in a more predictable and reproducible
tissue vaporization. The new system also softens
the transition between the atrophied skin of the
scar and the normal skin around it. They may also
trigger increased collagen production.
An adverse effect of old CO2 laser treatment was
char formation. The development of lasers with
high energy densities and ultra-short pulse durations
allowed controlled heat delivery and absorption,
resulting in char-free ablation. While most adverse
effects of the old CO2 lasers have been eliminated
by the new system, short-term problems like, transient
erythema, pruritis and transient scarring remain.
The single pass system, with fewer side effects,
may be safer than the multi pass system. One study
reported a more natural skin condition with single-pass
resurfacing. High fluences did not show more thermal
damage than average fluences.
Er: YAG resurfacing: Pulsed Er: YAG lasers, at
selected wavelengths are 10 times more selective
in targeting the water than CO2 lasers. They are
also more penetrating and may cause pinpoint bleeding.
However, although overall they cause less thermal
damage, the clinical improvement is less. This
laser is recommended for treating superficial atrophic
scars as they give results similar to CO2 lasers
and have reduced healing time.
Combined Er: YAG/ CO2 laser: This combined system
can deliver the ablation of the erbium wavelength
and the deeper penetration of CO2 laser. Studies
show reduced duration of crusting, swelling and
itching. This system seems to deliver just enough
non-specific energy to stimulate neocollagen production
and also vaporize enough tissue. The final word
on combined Er: YAG/ CO2 laser system must await
Non-ablative resurfacing of atrophic scars
This system has lately become fairly popular due
to mainly little or no downtime involved. The Nd:
YAG was the first laser system developed exclusively
for non-ablative skin resurfacing.
It employs light from the visible and mid infrared
sections of the spectrum. Non- ablative lasers
have been very successful in treating acne scars.
There are enough studies to corroborate this. The
ability of these lasers to improve skin texture
has also been well demonstrated.
The future may see non-ablative laser systems
combined with subcutaneous incision, punch excision
and fat grafting, in the treatment of acne scars.
Laser treatment for hypertrophic burn scars
These scars are more difficult to treat because
of their proliferative nature. Several trials have
proved the flash pumped 585nm PDL laser quite effective
in reducing pruritis, tenderness and burning, with
minimum pain and invasiveness. In future the benefits,
if any, of combined therapies or shorter pulse
widths in hypertrophic burn scars may be explored.