Silicone microinjections effective for HIV lipoatrophy

Atlanta - Injectable liquid silicone represents a safe, cost-effective and permanent treatment option for patients suffering from HIV lipoatrophy, according to an expert who has studied the material in this population for more than four years.

Surgical treatments for patients with HIV lipoatrophy traditionally include implants made of cadaveric dermis, rigid silicone or transplanted human tissue such as fat.

"All those surgical options tend not to work very well for a variety of reasons. They tend to be too expensive, and surgical recovery time and quality of corrections aren't very good. Furthermore, human tissue implants seem to become reabsorbed over time," says Derek H. Jones, M.D., clinical assistant professor of dermatology, University of California, Los Angeles (UCLA).

Silicone best for some

"However, there are tremendous numbers of HIV lipoatrophy patients who really do best with liquid injectable silicone, which is the only permanent injectable filler we can legally use (off-label) in the United States at present," Dr. Jones tells Dermatology Times. Advantages of this material include its permanence, as well as the fact that the finite number of treatments required makes it far more cost-effective than temporary fillers, he adds.

Dr. Jones points out that experience has taught physicians the paramount importance of purity in liquid silicone preparations. "Silikon 1000 (Alcon Laboratories) is an FDA-approved substance that is highly purified," Dr. Jones says.

This contrasts sharply with materials often used from the 1960s to the 1980s, when there was no Food and Drug Administration approval of liquid injectable silicone and the majority of these products being used cosmetically were bootlegged from industrial applications, he adds.

"Those products have been studied," Dr. Jones says, "and it has been proven that they're full of industrial contaminants. So the first thing that one should ask when one sees or hears of an adverse reaction to liquid injectable silicone used during those decades is 'What was used?' Frequently, the answer is 'We have no idea.'"

Strict adherence

In addition to using pure products suitable for human injection, Dr. Jones says physicians must adhere strictly to the microdroplet serial puncture technique.

This technique involves placing 0.01 cc injections under the subdermal plane or deeper, he explains, deposited at very close intervals within the area of depression.

"Over a period of time," Dr. Jones explains, "the body develops a limited foreign body reaction in the form of a tiny fibrous capsule around each microdroplet. That collagen deposition serves to anchor the microdroplet in place and to increase the amount of collagen deposition the patient achieves over time. So as time goes on, these patients look better and better, though it's not an immediate gratification."

Question of migration

Many physicians worry about migration with silicone, he allows.

However, Dr. Jones says, "Migration is really not a problem as long as one uses the microdroplet technique. Liquid injectable silicone is an oil, so migration is only a problem when one injects a large bolus all at once."

In a fairly recent trial, he and colleagues used the microdroplet method to treat 77 patients with a total of 376 injections (97 percent of which involved Silikon 1000).

Dr. Jones says, "The protocol we're using in lipoatrophy calls for no more than 1 cc on each side of the cheek at monthly treatment intervals (Jones DH, et al. Dermatol Surg. 2004 Oct;30(10):1279-1286). At this point, we've treated well over 1,000 patients at four different centers, and we're not aware of any serious adverse events using this protocol."