Biomedical Engineering Reference
In-Depth Information
If a decision is made to use this technique clinically, it is
imperative to learn the signs of depth of injury by observation
of tissue healing with variable levels of treatment on repeated
occasions. As mentioned earlier, the three end points of treat-
ment are elimination of the wrinkle or scar, a yellow-brown
discoloration indicating thermal damage, and no further col-
lagen shrinkage or tightening. When any one of these is
reached, the laser procedure should be terminated in that area
of the face. It is much safer to re-treat residual lines after an
adequate healing time of 6 months or longer.
treated area may continue to improve for several months after
laser resurfacing as collagen remodeling takes place.
Our studies of patients with an average follow-up of 2 years
postoperatively (range 1-4 years) have revealed an excellent
preservation of these results. Generally, as anticipated, the
lines fi rst to recur are those caused by muscle motion (“crow's
feet,” glabellar, and forehead). Excellent preservation of results
was seen, however, because 3-month versus 25-month scores
revealed an average improvement in preoperative photodam-
age scores periorally of 49% versus 38%, respectively, while
periorbital scores were 46% versus 31% improved (Fig. 6.23).
Interestingly, patient satisfaction for these two areas was 55%
for the perioral area and 80% for the periorbital area. Overall,
94 of 104 patients (90%) considered laser resurfacing to be a
benefi cial procedure that they would recommend to others
(105). This may be true because the laser removes the textural
and pigmentary abnormalities (the “weathered” look)
although the muscles may still be able to fold the skin into
wrinkles.
Other investigators have found similar results. Burns (per-
sonal communication) had independent observers grade 95
consecutive full-face resurfacing procedures at 90 days and
1 year postoperatively using a scale of 1-8 and found an aver-
age decrease in photodamage scores (Table 6.3). No difference
was seen in outcome whether patients were treated with the
previously used Coherent or Sharplan systems.
Ross et al. (106) reported the long-term results of 28 patients
treated with either the SilkTouch or the UltraPulse laser and
found that their pretreatment photodamage scores continued
to improve from 60 days to the reassessment point at 1 year.
Scores improved 43% in the SilkTouch group and 34% in the
UltraPulse group, but no statistical difference was seen between
the two groups. The immediate thermal damage was found to
be about 30% greater in the SilkTouch group, with a wider zone
of fi broplasia (220 vs. 150
facial wrinkling
To evaluate the severity of wrinkling and photodamage pres-
ent and therefore achieve some degree of predictability of
response to resurfacing, a clinical classifi cation and numeric
scoring system have been adapted from other photodamage
assessment systems. Although other wrinkling and photodam-
age assessment scales exist, the need for a system related purely
to visible wrinkling and visible textural changes secondary to
solar elastosis was thought to be more relevant to the topic of
wrinkle eradication (101).
Use of this scoring system allows broad classifi cation into
mild, moderate, and severe categories as well as a subjective
numeric severity score (Table 6.2). Assessing patients both
before and after treatment in a study with an average follow-up
of about 90 days revealed that the average patient's preopera-
tive score decreased approximately 50% as a consequence of
resurfacing (104). This means that mild wrinkles generally
resolve completely, moderate wrinkles become mild, and
severe wrinkles become moderate.
Other studies (3,4,97) using different assessment systems
have come to basically the same conclusion: wrinkles generally
improve 50-70%, with superfi cial lines eliminated, deeper
lines softened, skin texture normalized, precancerous lesions
eliminated, and lentigines and seborrheic keratoses eliminated.
These are realistic expectations for the patient although, occa-
sionally, even severe wrinkles may completely resolve. The
m in the UltraPulse group) at 1 year
postoperatively. No statistical difference was seen in adverse
effects for the two groups, although focal hypopigmentation
μ
Table 6.2
Facial Wrinkling: Clinical Classifi cations
Class
Wrinkling
Score
Degree of Elastosis
I
Fine wrinkles
1-3
Mild: fi ne textural changes with subtly accentuated skin lines
II
Fine-to-moderate
depth wrinkles
4-6
Moderate: distinct popular elastosis (individual papules with yellow translucency
under direct lighting) and dyschromia; moderate number of lines
III
Fine-to-deep wrinkles;
numerous
7-9
Severe: multipapular and confl uent elastosis (thickened, yellow, and pallid) lines;
with or without redundant skin folds approaching or consistent with cutis
rhomboidalis
(
A
)
(
B
)
(
C
)
Figure 6.23
Excellent long-term results after CO
2
laser resurfacing of facial wrinkles. (
A
) Before surgery: class III, level 8. (
B
) 14 months postoperatively: class II,
level 4. (
C
) 39 months postoperatively: class II, level 4. Note progression of photoaging of medial cheeks, which were not treated.
