Biomedical Engineering Reference
In-Depth Information
NAFL systems. A clinical example of results with 1927 nm are
shown in Figure 8.12. Results using a 1550 nm laser are shown in
Figures 8.13 and 8.14.
complication rate (26). The two most common complications
encountered were acneiform eruption and herpes simplex reac-
tivation. However, these were only encountered at a 1.87% and
1.77% rate respectively. Overall, NAFL is a very safe treatment
and has minimal side effects at the recommended settings.
Scars
Improvement in scars may signifi cantly improve the patient's
self-esteem and quality of life. Common causes of scars include
surgery, trauma, and acne. Two main categories of scars include
atrophic and hypertrophic scars. They can vary in color from
white to red to brown. In 2007, an initial pilot study by Vasily
studied 31 subjects with 13 surgical and 18 traumatic scars
using the Lux 1540-nm 10-mm handpiece (35). Treatments
using laser energies in the range of 30-60 mJ/mb, a 10-ms pulse
duration, 3-5 passes, and a series of 1-8 treatments were per-
formed. A blinded observer saw 51-75% improvement in scars
at 1 month after treatment in 59% of patients. The most
improvement was seen after the fi rst three treatments. NAFL
treatment of surgical scars was also compared with and outper-
formed the standard scar treatment of pulsed dye laser (PDL)
(36). A randomized blinded split-scar study was performed in
12 patients comparing the Fraxel RS (Reliant Technologies)
against the 595-nm V-Beam PDL (Candela Corporation, Inc.,
Wayland, Massasuchetts, USA). Treatment with a fl uence of
70 mJ, TL 8, and 16 passes was performed on the NAFL side
and with 7.5 J/cm
2
, pulse duration of 0.45 ms, and a spot size of
10
clinical applications
Nonablative lasers have been used to treat an expansive range
of conditions. Numerous clinical studies have shown its effec-
tiveness in a variety of treatments (19,27,28). The main areas of
treatment include photodamage and wrinkling, scars, stretch
marks, pigmentary disorders, and actinic keratosis. Evolving
applications include the enhancement of drug and topical
product delivery through NAFL resurfacing which takes advan-
tage of increased permeability of the epidermis and dermis
after treatment. Case reports have also shown NAFL treatment
to be useful in miscellaneous other applications that include
improving residual hemangiomas, minocycline-induced pig-
mentation, nevus of Ota, granuloma annulare, and male and
female pattern hair loss (15,16,29-32).
Photodamage
Many studies have examined nonablative fractional resurfac-
ing of the face and non-facial skin for improvement in sun
induced discoloration and wrinkles. In 2007, Wanner et al.
examined 50 patients with mild to moderate photodamage,
rhytides, and dyspigmentation who received three successive
treatments with a 1550-nm erbium-doped laser (Fraxel SR750,
Reliant Technologies, Inc.,
1
Mountain View, CA) (33). At least
51-75% improvement in photodamage was observed in 73%
and 55% of facial and non-facial (chest and neck) treated skin
at the 9-month follow-up. Fractional laser photothermolysis
for photoaging of the hands was examined specifi cally in a
small cohort of patients by Jih et al. (34). Ten patients were
randomized to either receive fi ve NAFL treatments with a
1550-nm laser (Fraxel SR, Reliant Technologies, Inc.) to their
left or right hand. Statistically signifi cant improvements in
skin pigmentation and skin texture were noted at the 1- and
3-month follow-up. Skin biopsies were also taken at baseline,
1- and 3-month follow-ups. The post-treatment biopsies
showed thickening of the epidermis and notably increased col-
lagen density in the papillary and upper reticular dermis.
Moreover, the study was safe and showed limited side effects.
A 1550-nm laser consensus panel also convened to discuss
their recommended treatment settings for photoaging (19).
The panel recommended settings of 10-20 mJ of energy with
a TL of 7-11 to improve dyschromia in patients with Fitzpat-
rick skin types I-III. For rhytides, specifi cally in the periorbital
region, the consensus recommended settings of 30-70 mJ of
energy using a TL of 7-11 with 8 passes. For dyschromia of the
neck and chest the panel recommended 10-40 mJ of energy
using a TL of 7-11 and 8 passes for Fitzpatrick skin types I-III.
Newer versions of the 1550-nm laser, as well as other NAFLs of
other wavelengths, have been developed since the consensus
meeting. Hopefully, another consensus meeting will be planned
that will include recommended treatment guidelines for all
3 mm was performed on the PDL side. After a series of
four treatments, greater overall mean improvement was seen
on the NAFL side (75.6%) compared with the PDL side
(53.9%). Also, hypopigmented scars, hypertrophic scars, and
traumatic thermal burn scars were studied in small cohorts and
demonstrated improvement with NAFL (37-39). The 1550-nm
NAFL consensus panel recommended the settings of 50-70 mJ
of energy with a TL of 7-11 for skin types I-III in the treatment
of surgical scars (19). Like surgical scars, acne scars can be cos-
metically and psychologically disturbing to patients. NAFL has
been proven successful in the treatment of acne scars. In 2008,
Weiss et al. presented a retrospective analysis of over 500 acne
scar treatments with the Lux 1540-nm laser (40). The fl uences
used were 50-70 mJ/mb with a minimum of three passes. Results
assessed by blinded photographic evaluation showed a median of
50-75% improvement in acne scars; 85% of patients rated their
skin as improved. Acne scars were also studied with the Fraxel
1550 nm SR750 (Reliant Technologies) by Alster et al. (41). Fifty-
three patients with acne scarring received three laser treatments.
Ninety percent of patients were found to have 51-75% improve-
ment by an independent observer. The 1550-nm laser consensus
panel meeting recommended selection of treatment settings of
acne scars based on skin types (19). They recommended settings
of 30-70 mJ at TL 7-11 for 8-12 passes for skin types I-III and
30-70 mJ, TL 4-5 and 8 passes for skin types IV-V. We presently
employ the Icon system with the 1540-nm XD handpiece for
scars and anecdotally have seen responses for scars resistant to
all other NAFL devices. Flattening of a scar after IPL tattoo
removal is shown in Figure 8.15.
×
Striae
Striae are disrupted areas of collagen in the skin that can occur
during growth spurts, topical and oral steroid use, and condi-
tions of hormonal change like pregnancy. It is estimated that
75-90% of women form some degree of stretch marks during
1
Reliant Technologies, Inc. was acquired by Solta Medical, Inc. in 2008.
