Biomedical Engineering Reference
In-Depth Information
long-term efficacy of ablative
fractional laser treatment
The durability of fractional results is highly variable and
dependent on a number of factors. These include age, degree
of preexisting photodamage, presence of other medical condi-
tions, amount of posttreatment ultraviolet exposure, and the
depth and density of lesions. In a study by Ortiz et al., a group
of 10 patients was evaluated at 1 and 2 years after their 3-month
follow-up postoperatively. Each was evaluated for overall skin
texture, laxity, rhytides, and acne scars. Within this small
group, it was found that subjects maintained 74% of their
overall improvement (50). Patients should be advised of the
durability of their treatment and measures that can be taken to
prolong the benefi ts of the procedure.
references
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photothermolysis: a new concept for cutaneous remodeling using
microscopic patterns of thermal injury. Lasers Surg Med 2004; 34:
426-38.
2. Tierney EP, Kouba DJ, Hanke CW. Review of fractional photothermolysis:
treatment indications and effi cacy. Dermatol Surg 2009; 35: 1445-61.
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focused infrared laser pulses: thermal effects at defi ned tissue depths.
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the zone of thermal injury produced by laser ablation of biological tissue.
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comparison of two ablative fractional carbon dioxide lasers for the
treatment of photodamaged facial skin. Dermatol Surg 2011; 37: 784-90.
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fractionally ablative modalities of a novel 2790 nm YSGG laser for facial
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induces tissue tightening. Lasers Surg Med 2009; 41: 78-86.
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contracture. Arch Dermatol 2011; 147: 1148-50.
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fractional device. Lasers Surg Med 2011; 43: 79-91.
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induced by carbon dioxide laser resurfacing of photodamaged human
skin. Arch Dermatol 2004; 140: 1326.
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responses after treatment using a fractional ultrapulse carbon dioxide
laser on back skin. Dermatol Surg 2011; 37: 1141-9.
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carbon dioxide laser resurfacing on photodamaged human skin. Arch
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2
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horizons of ablative
fractional technology
There have been many modifi cations to ablative fractional
devices to optimize the effi cacy of treatment while minimizing
adverse effects or associated downtime. Creative combinations
of NFR and AFR have been reported to enhance recovery and
effi cacy. Also, AFR can be confi ned with fi llers and neurotoxins
to enhance cosmetic outcomes. Fillers can be injected at the
same session (just before lasing) as the fi ller depths extend
beyond the reach of the ablative cylinders (51). The injection
of neurotoxins should precede AFR, but the minimum interval
is unclear. As the neurotoxin should be set by 30 minutes after
injection, this time might be the minimum interval. If injected
just before or just after AFR, edema might cause diffusion and
unwanted facial asymmetry after injection.
drug delivery
Because fractional ablation produces microscopic holes in the
skin, the compromise in epidermal integrity accelerates the
absorption of topical medications. In work done by Hadersdal
et al., increased uptake of methyl-aminolevulinic acid relative
to untreated skin was demonstrated in two Yorkshire pigs.
Additional work by Letada et al. demonstrated the absorption
of aminolevulinic acid after fractionated laser treatment to the
palms of fi ve human subjects. Absorption was demonstrated
using Wood's lamp fl uorescence (52). It has yet to be deter-
mined how well-increased absorption will translate into
increased therapeutic effect, but the theoretical underpinnings
appear sound. This could certainly have practical implications
in the treatment of many skin conditions, including premalig-
nant and malignant entities.
conclusions
The advent of ablative fractional technology has revolution-
ized the application of lasers to a variety of dermatologic con-
ditions. The lower incidence of side effects and decreased
recovery time compensates for a small decrease in overall effi -
cacy. Their utility has been proved in a variety of skin condi-
tions. As a greater understanding of the underlying mechanisms
of ablative fractional technology come to light, improvements
in current treatment will undoubtedly occur. Additional appli-
cations of fractional ablation are in the process of being inves-
tigated and hold promise for treating conditions of the skin in
novel ways.
