Biomedical Engineering Reference
In-Depth Information
spider telangiectasia
Spider telangiectasia represents telangiectasia with a central
feeding arteriole. They typically appear in preschool and
school-age children. The peak incidence appears to be
between age of 7 and 10 years, and as many as 40% of girls
and 32% of boys younger than 15 years have at least one
lesion (29-31). The incidence in healthy adults is about 15%.
The difference between these stated incidences implies that
50-75% of childhood lesions regress. However, this is not
easily observable because most lesions seem to persist with-
out change and become a source of cosmetic concern when
present on the face. The PDL has proved to be a very effective
treatment for these benign lesions (Fig. 2.17) (32). We also
routinely use the IPL with a small tip adaptor or a small spot
KTP laser.
Accordingly, treatment should be confi ned to very small spots
(<2 mm) and to the smallest fl uence suffi cient to close the
vessel. In this way the greatest fraction of incoming light is
converted to vessel heating versus nonspecifi c dermal heating.
Intense Pulsed Light
This high-energy pulsed light source described previously is
very effective in treating facial telangiectasia. Advantages are
the almost complete lack of purpura and adverse sequelae.
Fluences of 12-45 J/cm
2
are required for vessel ablation with
the original machines using a double pulse of 2.4-6.0 ms each
with a 10- to 30-ms delay between pulses (depending on skin
type). A 550, 560, or 570 nm cutoff fi lter works best. Lesions
usually clear in one treatment in 90% of patients. More mod-
ern IPLs, such as the Lumenis One and M22, use equal, double,
or triple pulsing to enhance effi cacy while minimizing exces-
sive epidermal heating (26). Lesions are treated with one or
two pulses until initial vessel spasm or slight purpura occurs.
The only potential side effects are slight purpura, which lasts 2
to 4 days, or epidermal desquamation when treatment is per-
formed on tanned or type III or IV skin. Epidermal desquama-
tion in pigmented patients can be avoided by changing the
fi lter to a longer wavelength or increasing the delay time
between double or triple pulses (see chap. 8).
A dual-mode fi ltering IPL (Ellipse Flex, Danish Dermato-
logic Development, Hoersholm, Denmark) that restricts fi l-
tered light to between 555 and 950 nm (median wavelength of
705 nm) has been shown to provide more than 50% reduction
in facial telangiectasia in 79% of patients after one to four
treatments; 37.5% of patients had greater than 75% improve-
ment (27). Another IPL light source [a.k.a. optimized pulse
light (OPL)] uses dual fi ltering and enhanced cooling. The
Max G handpiece (Palomar Medical Technologies, Burlington,
Massachusetts, USA) uses a 10 × 15 mm spot to coagulate ves-
sels (Fig. 2.15). Shorter pulses are optimal for light skin and
smaller vessels and longer pulses area applied for deeper vessels
in darker skin. A new addition is the Skintel, a builtin pigment
meter with Bluetooth connectivity that transmits skin pigment
levels back to the base unit and provides real-time test spot
guidelines for safe clearance of vessels with epidermal sparing
(Fig. 2.16) (28).
generalized essential telangiectasia
Telangiectasia generally occurs on the legs but may also involve
other cutaneous surfaces. Various treatments have been pro-
posed, with variable effi cacy (33). We also treated four patients
with the PDL at fl uences ranging from 6.0 to 7.5 J/cm
2
. Two
patients responded with total resolution, but two patients had
almost no improvement in their appearance (34). We have also
applied the large spot KTP laser with good results. Fluences of
6-8 J/cm
2
are applied with a 10 mm spot, cooling (contact) and
pulse durations of 18-22 ms. IPL treatment has also been
found to be effective (35).
rosacea
Rosacea is a cutaneous vascular disorder associated with fol-
licular infl ammation. A comprehensive review of the literature
fi nds that of the 18 histologic studies on rosacea, 14 showed
Figure 2.15
Typical IPL with 10 × 15 mm spot for vascular lesions. Unit allows
for multiple other handpiece attachments for other applications.
Figure 2.16
Pigment meter that optimizes parameter selection for vessel based
on epidermal tolerance.
