Biomedical Engineering Reference
In-Depth Information
15
Laser, light, and energy devices for cellulite and lipodystrophy
Mitchel P. Goldman, Jennifer D. Peterson, and Sabrina G. Fabi
background
Historically a sign of beauty and wealth, the presence of cellulite
is now considered esthetically objectionable. The term “cellu-
lite” is used in modern times to describe the dimpled or puck-
ered skin of the posterior and lateral thighs and buttocks seen in
many trim and overweight women. The appearance is often
described to resemble the surface of an orange peel or that of
cottage cheese. It affects all races and is estimated that 85% of
women over 20 years of age have some degree of cellulite (1).
Cellulite is known medically as liposclerosis, gynoid dystrophy,
edematofi brosclerosis, or dermopanniculitis (2). The condition
is best described by Goldman as a normal physiologic state in
postadolescent women, which maximizes adipose retention to
ensure adequate caloric availability for pregnancy and lactation
(3). Adipose tissue is also essential for nutrition, energy, sup-
port, protection, and thermal insulation (4).
Many of the currently accepted cellulite therapies target
defi ciencies in lymphatic drainage and microvascular circula-
tion. Devices utilizing either exclusively or in combination are
radiofrequency (RF)-, laser-, and light-based energies; many
coupled with tissue manipulation are available for the
improvement of cellulite. Laser-assisted liposuction with and
without autologous fat transfer for the improvement of the
appearance of cellulite has also been utilized. Although
improvement using these devices is temporary, they may last
for several months. Thus, patients who wish to have smoother
skin with less visible cellulite can have a series of treatments
and then return for additional treatments as necessary.
Unfortunately, these predisposing factors are diffi cult if not
impossible to alter and thus cellulite prevention is currently
not attainable.
Histology
At the histologic level, cellulite is the result of localized adi-
pose deposits and edema within the subcutaneous tissue.
In women, fascial bands of connective tissue are oriented
longitudinally and extend from the dermis to the deep fas-
cia. These bands form fibrous septa, which segregate fat
into channels resembling a down quilt or mattress, and the
subcutaneous fat is projected superficially into the reticu-
lar and papillary dermis. As the fat layer expands, the per-
pendicular connective tissue remains fixed and anchored to
the underlying tissue, creating a superficial puckered
appearance of the skin (4,7,8). Ultrasonic studies of cellu-
lite have shown the striking feature of herniation of the
subcutaneous fat into the reticular and papillary dermis
(Fig. 15.1) (9).
Fatty acids are believed to be modifi ed through peroxida-
tion by free radicals. These events are hypothesized to contrib-
ute to the worsening of local microcirculation by disrupting
venous and lymphatic drainage. This skin phenomenon is
rarely found in men as the connective tissue in males is not
normally arranged vertically, but rather in a crisscross pattern
that is gender-typical for the skin of the thighs and buttocks
(Fig. 15.2) (4,7).
Pathophysiologic Mechanisms of Cellulite
The pathophysiology of cellulite is multifactorial. Adipose
tissue is vascular, leading to the theory that cellulite may
worsen in predisposed areas where circulation and lymphatic
drainage have been decreased, possibly due to local injury or
infl ammation. Under normal conditions, fat cells are embed-
ded in a network of reticular fi bers. In cellulite, interstitial
edema results from an increased permeability in the local
microvasculature. As a result, a chronic infl ammatory pro-
cess ensues around the reticular fi ber network. Subsequently,
the reticular fi bers increase in number (hyperplasia) and
thickness (hypertrophy), worsening the compromised micro-
circulation (3). This is evident clinically as the classic “orange
peel” appearance of overlying skin and in reduced blood
perfusion.
The formation of cellulite is also under a hormonal infl u-
ence. Estrogen is known to stimulate lipogenesis and inhibit
lipolysis, resulting in adipocyte hypertrophy. This may explain
the onset of cellulite at puberty, the condition being more
prevalent in females, and the exacerbation of cellulite with
Predisposing Factors
There are many predisposing factors that contribute to cellu-
lite development. These include the following:
1. Gender—Due to the underlying structure of fat and
connective tissue described below, women are more
likely to develop cellulite.
2. Heredity—The degree and presence of cellulite, as
with body habitus, are often similar between females
within the same family.
3. Race—Cellulite is more common in Caucasian women
than in Asian or African-American women (5).
4. Increased subcutaneous fat—Due to the unique his-
tology of cellulite-affected skin, more adipose tissue
in the subcutaneous layer enhances the appearance
of cellulite on the skin surface (6).
5. Age—Post puberty, women begin to develop cel-
lulite as part of normal anatomic and physiologic
development. With advancing age, cellulite increases
in severity as a refl ection of thinning of the epidermis.
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