Silicone injection study in HIV patients shows good results

Lake Buena Vista, Fla. — With about 50 percent of HIV patients suffering from facial lipoatrophy and with several possible methods of correction, there is a healthy interest within the aesthetic community as to what works best to treat a rapidly growing problem.

Derek Jones, M.D., has taken part in a four-year open pilot trial to determine the efficacy and safety of highly purified 1000 centistoke silicone oil for HIV-related lipoatrophy. Early results from the study are to be published soon in the Journal of Dermatologic Surgery.

To date, 700 patients have been injected with the silicone oil with an off-label usage; highly purified 1000 centistoke silicone oil has been approved by the U.S. Food and Drug Administration (FDA) for intraocular injection for the tamponade of retinal detachment.

So far, Dr. Jones and his group are pleased with the results, but he notes, "We don't know the long-term safety of this treatment, so the patients have to be followed very, very carefully. We do have some patients who have almost four years' follow-up. But we really need to follow patients for five to 10 years before we pass judgment on long-term safety."

Silicone, of course, has been the subject of much debate — in the medical and social realms alike. Dr. Jones acknowledges this, citing its detractors believe that silicone is ultimately too unpredictable.

But, he says, "People who do a lot of this kind of thing, like David Orentreich and others who have a wealth of anec-dotal data to rely on, say that the incidence of serious complications should be rather low, using a very highly purified substance and microdroplet injection technique."

Furthermore, two studies with Dow Corning's injectable silicone MDX-4-4011 were completed in the '70s and '80s. In those studies, the results of liquid injectable silicone injected in 200 patients with facial lipoatrophy not related to HIV suggestsafety and efficacy of highly purified silicone injected correctly, with only a 1 percent severe complication rate.

The current study protocol calls for a strict microdroplet serial puncture technique (0.01 mL microdroplets injected at 2 to 4 mm intervals into the subdermal plane with a 30-gauge needle), with the filler injected in limited amounts (2 ccs per treatment) at monthly or longer intervals. Prior to treatment, Dr. Jones suggests a topical anesthetic such as benzocaine, because injectable anesthetic might alter the pre-treatment facial contours.

Just one complication Thus far, out of 700 patients, the group has only recently encountered a single patient who developed a complication. That patient experienced a hardening of the silicone in the treated areas. The patient had surgical Alloderm implants that had reabsorbed prior to the silicone injections, and Dr. Jones was considering whether that played a possible factor in the current complication. But, either way, the complication has not been disfiguring and is being treated with antibiotics and steroid injections, he says.

Dr. Jones finds highly purified 1000 centistoke silicone oil to be a desirable substance to treat these patients for several reasons. First, the volumes of temporary fillers required for optimal correction are cost-prohibitive.

Secondly, the correction with temporary fillers dissipates within a few months and these patients often demand fillers that are permanent.

Third, liquid silicone is the only permanent filler that can be legally used on an off-label basis in the United States without a formal Investigational Device Exemption (IDE) from the FDA. With liquid silicone, he believes, the results are good, and more importantly, he says, "It is by far the cheapest filler substance that we have on the market these days, on a volume-per-volume basis.

So it is extremely cost-effective for these individuals who require a fair amount of volume to correct their problem."

And, as a patient's lipoatrophy progresses, he finds that silicone tends to be "more supple, more forgiving, like regular soft tissue," unlike another permanent option, surgically placed rigid implants.