Review of Long-Lasting Dermal Fillers

The fillers discussed so far have limited duration in
tissue, requiring patients to return for retreatment
every four to six months to maintain cosmetic benefit.
Others, such as liquid injectable silicone (LIS),
last for years or may be permanent.
Liquid silicone has a long and controversial history
as a filler. Developed in 1945 by Dow Corning
Corp. for military purposes, silicone was introduced
to cosmetic medicine in the 1960s as a filler
gel for breast implants 9 and later for soft tissue
augmentation. 10 Although silicone produces cosmetic
benefits, silicone granulomas have been
reported 11 and injection of impure silicones has
resulted in serious complications, 12 some appearing
many years after implantation. 13
A comprehensive review of possible causes and treatment
options for granulomas associated with all
injectable dermal fillers will be available in 2006. 14
Adverse reactions and complications (including
granulomas) of fillers have been reviewed recently. 15,16
Lips augmented with
liquid silicone.
Two medical-grade silicones (both LIS) are currently
available: (1) Silskin ( Richard-James, Inc.
Peabody, Mass.), which has received an
Investigational Device Exemption for a clinical
trial on facial wrinkles, and (2) Silikon ® 1000 (Alcon
Laboratories, Inc., Forth Worth, Texas), which is
FDA cleared as an injectable tamponade for retinal
detachments. The FDA Modernization Act of 1997
permits FDA-cleared devices to be used “off-label”
for any condition within the doctor-patient relationship,
such as soft tissue augmentation.
The risks and benefits of using liquid silicone for
soft tissue augmentation have been the subject of
considerable debate. Experts agree, however, that
the quality of results depends on technique, minor
complications may occur even with good technique,
serious complications are rare when small volumes
of sterile pure liquid are used, and serious complications
can occur years after treatment. They also
agree that dislocation—in this case, movement of
silicone from the site of injection to another body
site—may result if large volumes are injected.
When this occurs, the silicone is not contained by
tissues into which it is injected, causing the filler to
move due to muscle contraction or gravity. 17
As with temporary fillers, injection technique is
critical to success with LIS. The microdroplet
serial puncture technique has been used extensively
for silicone injections. With this technique,
migration is eliminated because the microdroplets
stimulate fibroplasia and the formation of a
collagen capsule that holds them at the implantation
site. Silicone microdroplets displace dermal
connective tissue and new collagen is deposited
around the microdroplets, resulting in augmentation.
The amount of new collagen synthesized is
predictable and self-limiting. Injections are made
over several time intervals to assure slow but progressive
collagen formation. Since augmentation is
gradual, undercorrection (rather than overcorrection)
is appropriate. 18 The microdroplet technique
requires several repeat treatments, and the time
interval to visible improvement is longer than with
other fillers. 19
Optimal results are obtained when silicone is injected
beneath the layer in which the defect originates.
For example, injecting LIS just below the dermis is
appropriate for correcting contour depressions in
which dermal and epidermal layers of normal thickness
lie above a subdermal layer of insufficient
depth. If LIS is injected into the dermal or epidermal
layer, beading and granulomas may result.
Beading and overcorrection can be treated with
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Review of Long-Lasting Dermal Fillers
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