METHODS
Four patients were recruited into this institutional review
board-approved study. All patients presented with at least
twenty 0.5- to 1.5-mm umbilicated yellow papules consistent
with sebaceous hyperplasia. The laser was a 1,720-nm laser
(Del Mar Medical Technologies, Del Mar, CA) delivering up to
5 W through a 400-µm fiber (0.22 numerical aperture). Power
was measured through a built-in power meter. Test spots were
performed after photographs were taken with a Nikon digital
SLR camera (Model D90; Melville, NY) equipped with a Canfield
twin flash (Canfield Imaging Systems, Fairfield, NJ) with
and without polarization. The power to tissue was up to 4 W.
Dwell times ranged from 30 to 200 ms, The spot size was 500
to 750 µm, and average dwell time (on time) of 50 ms resulted
in a fluence of about 45 J/cm2. The desired end point was a
change from a pretreatment granular yellow appearance to a
creamy, white, smooth surface (Figure 2). In some cases, the
individual lobules were observed to extrude from the surface.
A pinpoint pirouetting technique was applied to treat larger lesions,
where individual lobules were heated with the fiber tip
held about 1 to 2 mm off the skin's surface. For smaller lesions,
the entire lesion was treated with one pulse. Settings ranged
from 3 to 3.8 W, and pulse durations in continuous wave mode
from 50 to 200 ms. Representative settings are described in
Table 1. After the test spots were performed, patients returned
in 3 weeks for evaluation. The treating physician determined
the best settings by noting the parameters that achieved the
greatest reduction in lesion size with the lowest number of
side effects. Two treatment sessions were carried out at 3- to
4-week intervals, and the final follow-up was 12 weeks after
the final treatment. Test spots showed that the optimal setting
combination was 4 W (maximum power to tissue) and 50 ms.
The spot size at the skin's surface was estimated to be 0.075
to 1 mm. The resulting calculated fluence was about 45 J/cm2.
Smaller dwell times resulted in inadequate heating (lack of
clear coagulation response), and longer dwell times and lower
powers resulted in poorer heat confinement (coagulation that
extended beyond the lesion perimeter). Damage to adjacent
normal skin showed no change until the dwell time exceeded
2 times that of the sebaceous hyperplasia. One 2-mm punch
biopsy was obtained just after treatment in 1 patient.
Four weeks after the final treatment, 3 dermatologists blinded
to the date of the photographs and uninvolved with the study
evaluated the photos and scored them based on a global assessment
comprised of: 1) lesion diameter, 2) lesion height,
and 3) lesion color. Diameter was measured by using the
background identification tape that was scored in mm. Height
was measured by scoring a lesion as flat or raised. The color
was either yellow or flesh color. The grading system used
the following scale to assess global improvement: 0 = no
improvement, 1 = 1% to 25% improvement, 2 = 26% to 50%
improvement, 3 = 51% to 75% improvement, 4 = 76% to 99%
improvement, and 5 = complete removal.
RESULTS
All patients completed the study. The mean transmitted power
and dwell times were 3.5 W and 50 ms. Immediate responses
with increasing dwell times from 20 to 200 ms over the same
power density ranged from no response to coagulation that
