Biomedical Engineering Reference
In-Depth Information
Figure 9.7
Improvement in facial burn scar following treatment with Fraxel Re:Pair.
Source
: Photo courtesy of William Groff, MD.
surgery using 50 mJ of pulse energy, density of 100 spots/cm
2
,
2 passes in the static mode (coverage 12.7%). Follow-up results
3 months after treatment revealed that 4 of 23 patients had
near total clinical improvement (>75%), 8 marked improve-
ment (51-75%), and 9 moderate improvement (26-50%).
Two patients had posttreatment hyperpigmentation that
spontaneously resolved within 1 month (Fig. 9.8).
Ozog and Moy published a clinical trial showing that intraop-
erative treatment of surgical wounds using a fractional CO
2
laser
improved the appearance and texture of the surgical scar (99).
penetrate deep into the dermis. These scars are commonly seen
on the mid-cheeks and chin. The second category, boxcar scars,
may be shallow or deep, but generally measure 1.5-4.0 mm in
diameter and have sharply defi ned, often vertical walls and the
base may be very fi rmly bound down. The third category,
rolling hills, have soft edges and may be circular or linear but
generally >4 mm in diameter. A simple but very signifi cant test
regarding possible response to treatments that tighten the skin
is to grasp the skin tightly and observe how much improve-
ment results with simply stretching the skin. Rolling hills scars
will usually improve 50-100% with this maneuver, whereas
boxcar scars show minimal improvement (0-25%) and ice-pick
scars show no change.
When treating rolling hills scars, full face or full areas are
generally treated with procedures that peel the skin and stimu-
late new collagen. These will be discussed in greater detail.
For the ice-pick and boxcar scars, a better result may be
obtained by fi rst performing a surgical procedure: punch or
elliptical excision of the scar to convert it to a linear scar that
can then be blended. Punch elevation of the base of the boxcar
scar may also be considered (103). The sharply defi ned edges
of a boxcar scar may also be improved by the use of ablative
resurfacing precisely to convert the scar to a soft rolling hills
scar that is much more responsive to treatment. Subcision was
fi rst described by Orentreich and Orentreich in 1995 (105), as
a procedure using a tri-bevel needle to puncture the skin and
then in arcs parallel to the surface of the skin to break up scar
tissue that is binding the base of an atrophic scar. This proce-
dure has been particularly promoted for rolling hills scars and
is said to induce neocollagenesis over 6 months or more (106).
Improvement of approximately 50% has been reported (107)
and some consider it the surgical procedure of choice for roll-
ing hills scars (103). However, this author's experience is more
acne scarring
One of the most common and diffi cult conditions to treat is
acne scarring. It almost always requires more than one treat-
ment session and more than one treatment modality to be
successful.
The most comprehensive acne study performed, HANES-1
(100), studied 20,749 US citizens of age 1-74 years in 1978 and
found the prevalence of acne vulgaris to be 68 per 1000. A more
restricted study of 749 patients aged 25-58 years (101) deter-
mined overall acne prevalence as 58% for women and 40%
for men. Scarring was noted in 14% of the women and 11% of
the men (102). Even though there are very effective treatments
for acne, only 16% seek appropriate treatment (103), which
greatly increases the risks and incidence of scarring.
It is useful to classify acne scars morphologically in order to
choose an appropriate treatment modality. A simple classifi ca-
tion deals with tissue loss or excess. If there is excess tissue, we
are dealing with a hypertrophic scar or keloid—most common
along the jawline and glabellar areas.
Jacob et al. (104) describe a useful classifi cation of acne scars
with loss of tissue or damage to tissue. Ice-pick scars are small
in diameter (<2 mm) but have sharply defi ned edges and
