Biomedical Engineering Reference
In-Depth Information
(
A
)
(
B
)
Figure 2.23
Congenital hemangioma (
A
) before and (
B
) after being treated in four sessions two months apart with alexandrite laser (8 mm, 3 ms, 45 J/cm
2
, and
60 ms spray, 30 ms delay with cryogen spray). Note small scar after crusting in one area after laser.
clear” of IH at 1 year (169). Limitations of this study include a
small spot size (5 mm), low fl uences, the lack of use of a cooling
handpiece, and a small number of treatments in the laser group.
When considered in total, a 2011 Cochrane analysis found
insuffi cient evidence to support PDL (and other laser) for
uncomplicated IH (170).
Other lasers have been used to treat IH. This list includes
the argon and Nd:YAG lasers, which may cause more signifi -
cant scarring than PDL. A retrospective study comparing
PDL (585 nm) and frequency-doubled Nd:YAG 532 nm
(i.e., “KTP”) lasers demonstrated less clinical effi cacy
(i.e., cessation of growth or regressive tendency) with KTP.
Side effects, including purpura, crusting, and postinfl amma-
tory pigmentary changes, however, were less common with
KTP than with PDL (171). Alexandrite lasers have also been
applied to IH. We advise very conservative fl uences with
larger spots (25-30 J/cm
2
and 12 mm, or slightly higher fl u-
ence with smaller spots (8 mm)). In any case, aggressive cool-
ing will limit the likelihood of ulceration and scarring
(Fig. 2.23). Pain can be managed by topical anesthetics but
the child will have to be restrained as well. One issue with
alexandrite and Nd:YAG lasers is the potential for unwanted
hair reduction, particularly in the area of the brow and scalp;
therefore, their use in these areas should be confi ned to those
cases where there is a clear benefi t-to-risk ratio. Percutaneous
treatment with a bare fi ber Nd:YAG laser has been used to
treat deep hemangiomas (172). Ablative fractional lasers are
also being explored for their role in treating fi brofatty residua
from involuted hemangiomas and scars secondary to previ-
ous surgical excision (173).
the lesion by 80% in volume and occasionally the lesions will
disappear after one treatment (Fig. 2.24). Surface cooling must
be applied to prevent epidermal injury. The 810 nm diode
laser can be used. We have also used the Nd:YAG laser with
3-5 mm spots and fl uences ranging from 50 to 100 J/cm
2
. With
the 1064 nm laser, the endpoint should be very slight lesion
shrinkage. Again, surface cooling must be applied. IPL can also
be used with a range of pulse durations and fl uences. Any
device with contact cooling should be held against the skin
surface with only gentle pressure lest the lesion be overcom-
pressed and all of the chromophore is displaced. The PDL with
compression has also been applied (using just enough com-
pression to reduce the lesion thickness); however, in this sce-
nario no cooling will be available.
Glomus Tumor
Small glomus tumors have been successfully treated with the
PDL (174). We have found that the Nd:YAG laser achieves
good resolution in deeper bluer lesions. Normally the Nd:YAG
laser is applied with a 3 mm spot and cooling with fl uences
ranging from 120 to 200 J/cm
2
and about 50 ms. Larger lesions
require smaller fl uences and smaller lesions will require higher
fl uences. The endpoint is a slight immediate shrinkage of the
lesion (175).
Blue Runner Bleb Nevus
We treat these lesions with the Nd:YAG laser with a 2-4 mm
spot size, surface cooling, and fl uences ranging from 80 to
130 J/cm
2
.
Angiofibromas and Fibrous Papules
Angiofi bromas are (176) associated with tuberous sclerosis.
These lesions are best treated with a 1-2 mm spot CO
2
laser
either in pulsed or CW mode. The lesions can be vaporized to a
depth just beneath the skin surface. For CW mode we normally
use powers from 2 to 5 W and for pulsed mode 200-400 mJ
pulse energies. Very red individual lesions can be treated
with the PDL or KTP laser. An article reported combining elec-
trosurgery for individual lesion with fractional CO
2
laser and
PDL (176).
Venous Lakes
Venous lakes are 2-8 mm diameter red-blue nodules that
typically occur on the lower lip. These “varicosities” of the lip
respond to a number of lasers and/or IPLs. For very small
lesions the KTP and PDL are helpful. For larger lesions, the
depth exceeds the “reach” of the GY technologies so that lon-
ger wavelengths are favored. Our favorite newest approach is
the 6 mm spot alexandrite laser with a 3-ms pulse and a fl u-
ence of 60-80 J/cm
2
. Often one treatment session will reduce
