Biomedical Engineering Reference
In-Depth Information
(
A
)
(
B
)
Figure 6.31
(
A
) Deep lines of forehead, glabella, and lateral canthi caused by muscle movement frequently recur after laser resurfacing. (
B
) Pretreatment with
Botox results in more signifi cant, longer-lasting improvement.
Contraindications
Box 6.2 lists possible contraindications to resurfacing.
Box 6.2
Relative Contraindications to Skin Resurfacing
Possible Abnormal Wound Healing
• Prior isotretinoin (Accutane) treatment within 1-2 years
• Keloids/hypertrophic scars
• Scleroderma/collagen vascular diseases
• Immunosuppressive drugs
Decreased Adnexal Structures of Skin
• Prior radiation therapy
• Prior deep phenol peel
• Burn scars
Infectious Diseases
• HIV/AIDS
• Hepatitis C
• Active herpes simplex
• History of recurrent infections/anergy
Koebnerizing (Isomorphic) Diseases
• Labile psoriasis
• Severe eczema
• Vitiligo
Medical Conditions
• Significant diabetes
• Problematic hypertension
• Significant cardiovascular/pulmonary disease
preoperative care
Currently, there is no consensus on what the most appropriate
preoperative skin care regimen is to prepare the skin for cuta-
neous laser resurfacing (42,120,121). In fact, many studies have
questioned the need for a preoperative skin care regimen at all.
Topical tretinoin has been shown by a number of studies to
stimulate epithelial proliferation and regeneration and to
decrease epidermal melanin content (140,141). Additionally,
topical tretinoin acid has been shown in a number of studies to
speed reepithelialization and improve clinical outcome when
used to prime the skin before dermabrasion and chemical peels.
Extrapolation from the literature reporting the benefi ts of
tretinoin acid when used prior to dermabrasion and chemical
peels led to its widespread use by cosmetic surgeons prior to
laser skin resurfacing. In a 1998 survey of physician members
of the American Society of Laser Medicine and Surgery, 80%
of the 116 responders reported that they pretreated cutaneous
laser resurfacing patients with topical tretinoin (2).
However, the widespread use of tretinoin preoperatively was
not based on well-controlled clinical studies. Investigations
have questioned the benefi t of pretreatment with topical treti-
noin before cutaneous laser resurfacing. In a randomized,
side-by-side comparative study, Orringer et al. pretreated
patients who underwent CO
2
laser skin resurfacing of the fore-
arms with topical tretinoin (0.05%) for 3 weeks. Posttreatment
biopsy specimens were obtained at baseline and at various
times (1 day to 6 months). They found no evidence of
enhanced collagen formation, accelerated reepithelialization,
or quicker resolution of postoperative erythema with tretinoin
pretreatment before CO
2
laser resurfacing (142).
Moreover, adverse side effects secondary to tretinoin pre-
treatment have been reported. Some authors believe that topi-
cal application of tretinoin before cutaneous laser resurfacing
may contribute to prolonged erythema postoperatively (143).
Skin irritation and exacerbation of facial telangiectasias are
also potential hazards of tretinoin therapy according to other
authors (144,145). Given the lack of well-controlled clinical
trials showing a benefi t, and the risk, albeit small, of adverse
side effects, it seems judicious to reexamine the current wide-
spread use of tretinoin as a pretreatment medication for the
laser resurfacing patient.
Up to one-third of patients experience postinfl ammatory
hyperpigmentation after laser resurfacing (16). The risk of
hyperpigmentation after laser resurfacing parallels the degree
of a patient's natural skin pigmentation and it is most preva-
lent in patients with Fitzpatrick skin phototypes greater than
III (5). To reduce the incidence of postinfl ammatory hyper-
pigmentation, many laser surgeons routinely pretreat patients
with skin phototypes III-VI with a combination of topical
skin lightening agents, including tretinoin, hydroquinone,
kojic acid, azelaic acid, and alfa-hydroxy acids, for 4-8 weeks
prior to cutaneous laser resurfacing (121).
The widespread use of these skin lightening agents before
cutaneous laser resurfacing was highlighted by a 1998 survey of
physician members of the American Society of Laser Medicine
and Surgery; 80% of the 116 responders reported that they
routinely pretreated their patients with topical tretinoin, 69%
pretreated with hydroquinone, and 10% pretreated with gly-
colic acid cream.
