Biomedical Engineering Reference
In-Depth Information
(
A
) Pre-treatment
(
B
) Post-treatment with MaxG
Figure 2.18
Telangiectasia (
A
) before and (
B
) after treatment with intense pulsed light (30 J/cm
2
, 10 ms).
vessels alone will achieve marked clearance. The apparent par-
adox arises from the relative small percentage of neck discolor-
ation that stems from melanin versus excess deoxy-HgB.
Stamatas and Kollias found that a fraction of the apparent
hyperpigmentation was deoxy-HgB being interpreted by the
eye as melanin (they share a common refl ectance pattern near
the 560 nm deoxy-HgB peak) (49). Fractional lasers have
recently been shown to reduce the redness and hyperpigmen-
tation associated with poikiloderma. One investigator (50)
applied the 1550 nm laser and reported a “signifi cant”
improvement using 8 mJ and 2000 MTZ/cm
2
after a single
treatment. Tierney et al. (51) applied a fractional CO
2
laser
and after one to three treatments found 65% reduction in red
and brown dyschromias. One should use caution in treating
the neck with ablative fractional lasers, as the recovery tends to
be compromised in this very thin skin.
hyperpigmentation comprising poikiloderma was observed in
an average of 2.8 treatments. Incidence of hypopigmentation
was 5% (52,53). A second expanded study of 135 patients
randomly selected with typical changes of poikiloderma on the
neck and/or upper chest were treated one to fi ve times every four
weeks with the IPL. Clearance of over 75% of telangiectasia and
hyperpigmentation comprising poikiloderma was observed.
Incidence of side effects was 5% including pigment changes.
In many cases, improved skin texture was noted both by physi-
cian and patient.
Approximately 75% improvement occurs after one treat-
ment. Side effects include transitory erythema from 24 to
72 hours. Purpura occurs only 10% of the time and only with
some pulses in variable locations. This purpura is different
from that seen with the PDL in that it is intravascular and
resolution occurs within 3 to 5 days. A slight stinging pain
during treatment is easily tolerated for up to 60 pulses per ses-
sion. No anesthesia is required, and the entire neck and chest
area can be treated during one treatment session (Fig. 2.19).
Patients must be informed that “footprints” representing the
shape of the contact crystal may be present after the fi rst and
even second treatment and is a normal response. One caution
is the use of IPL in tanned and darker-skinned patients.
Unlike PDL, where so long as cryogen cooling is applied, a
suffi cient fl uence to close vessels is usually “epidermis-safe”,
the “sweet spot” for IPL, that being the fl uence that closes ves-
sels but spares the background epidermal melanin, is quite
small. Test spots are advisable. Applying hydroquinone and
waiting for the patient to “de-tan” over a month are other
tools to increase the ratio of vascular-to-melanin heating.
Pulsed Dye Laser
We recommend that if the PDL is used to treat poikiloderma
of Civatte, it be used with a 10-mm-diameter spot size. In one
scenario, fl uence should be just strong enough to give a mini-
mal purpuric response (about 5-6 J/cm
2
, 1.5 ms and cooling).
Patients must be told that three to fi ve treatments will be nec-
essary and that the treated area may appear to be polka-dotted
until all treatments are given. An alternative nonpurpuric
approach uses the same 10 mm spot and fl uences ranging
from 7 to 9 J/cm
2
with aggressive cooling and 10- to 20-ms
pulse duration. This approach might require additional
treatments but will be less likely to create the temporary
honeycombed pattern that purpuric settings tend to cause.
Also, most patients resist the objectionable appearance of
purpura.
capillary malformations
including nevus
simplex and port-wine stains
(
)
Capillary malformations are among the most common vascu-
lar malformations of the skin, affecting 0.3-0.5% of newborns
(54). They appear to have an equal sex distribution and,
although familial cases have been described, most capillary
malformations arise sporadically (55). These lesions are usu-
ally noted at birth appearing as pale pink macules and patches;
they may be misdiagnosed as a bruise or erythema from birth
trauma (56). They may be single or multiple lesions. They may
present as small isolated patches or involve an entire limb or
signifi cant portion of the face or neck. Lesions on the face may
extend to the lips, gingival, and/or oral mucosa.
Intense Pulsed Light
Our results using an IPL have been favorable. With a pulsed light
system, the target is both vascular and epidermal and dermal
melanin. Various settings are applied that are device specifi c.
Both single, double, and triple pulse confi gurations have been
applied with good results. Multiple sessions are normally neces-
sary to achieve an optimal clinical result. This experience has
been detailed in a study in which 66 patients with typical changes
of poikiloderma on the neck were treated with IPL at various
settings every four weeks until desired improvement occurred.
A 50-75% improvement in the extent of telangiectasia and
