Biomedical Engineering Reference
In-Depth Information
signifi cant improvement in color match, stiffness, thickness,
and irregularity. The results were maintained at follow-up vis-
its at 6 months after last treatment. The authors suggested that
laser treatments may be more effective for earlier treatment of
scars as two patients who had no improvement had scars for
more than 2 years after surgery (Fig. 9.3).
As previously discussed with the PDL, earlier treatment with
the 1550-nm fractional Er:Glass laser to prevent hypertrophic
scar formation has been reported by Choe and colleagues (81).
Twenty-seven Korean patients at 2-3 weeks postoperative of thy-
roidectomy received four sessions with the MOSAIC laser®
(Lutronic Corp., Seoul, South Korea) using 10 mJ, 1500 spot/cm
2
,
and static mode at 1-month intervals. Subjects were compared
with a cohort of untreated thyroidectomy scars at 6 months
after the fi nal treatment. The laser-treated scars achieved sig-
nifi cantly better cosmetic results than the untreated control in
the aspects of prevention of hypertrophic scar formation and
the Vancouver Scar Scale, which is based on the grade of pig-
mentation, vascularity, pliability, and height of scars. The
authors suggest that using low-energy, high-density parame-
ters may avoid excessive stimulation of cytokines in the deep
dermis that can result in a greater chance of scar formation
and can be safely used in colored Asian skin. Although further
practical experiences with diverse parameters are required to
establish a standardized protocol for postsurgical scarring,
including the exact timing of scar treatment, earlier treatment
with lasers and light devices, including fractional lasers,
appears to optimize the wound healing process and possibly
suppress the formation of hypertrophic scar (68,82).
Tierney et al. (73) hypothesize that the success of NAFR in
treating scars is related to delivering high-energy pulses deep
in the dermis, while Choe et al. (81) suggest that the preven-
tion of scarring with the use of NAFR may be related to the
use of high density, but low-energy pulses in order to avoid
stimulation of the deep dermis. It is possible that these two dif-
ferent situations require different laser parameters for success
(Figs. 9.4 and 9.5).
Kunishige and colleagues also confi rmed that nonablative
fractional laser treatment can be effective in different types
of scars, including hypertrophic, atrophic, erythematous,
and hyperpigmented (83). Thirteen patients with surgical
scars were treated up to eight monthly sessions (average 3)
with the Fraxel Re:Store laser using energy levels from 6 to
70 mJ and fi nal densities from 312 to 2500 MTZ/cm
2
(about
17% to >100% coverage). At the 2-month follow-up visit,
almost all patients achieved at least 50% improvement with
more than half of the subjects achieving 75% improvement
or greater. Differently from other studies, the authors found
that scars older than 1 year improved as much as scars that
were younger.
(
A
)
(
B
)
Figure 9.2
(
A
) Multiple fl at scattered hypopigmented scars of nose are present 15 years following pulsed CO
2
laser resurfacing and 10 treatments of Fraxel Re:Store
at 1- to 6-month intervals. (
B
) The addition of topical bimatoprost BID (Latisse) and tretinoin 0.025% qd resulted in >75% improvement in the hypopigmentation.
(
A
)
(
B
)
Figure 9.3
(
A
) Sharply defi ned atrophic hypopigmented scars are very visible 3 months after a brow lift positioned just superior to the eyebrows bilaterally.
(
B
) Signifi cant improvement in color and texture is seen after 4 treatments with Fraxel Re:Store performed at 2- to 4-week intervals using 40 mJ and 36% density.
(
A
)
(
B
)
Figure 9.4
(
A
) Abdominoplasty scar 2 weeks following suture removal. (
B
) The scar is cosmetically improved by the use of Fraxel Re:Store starting 2 weeks after
suture removal and repeated at 4-week intervals for four treatments using 30 mJ and 17% density.
