02 March 2007 (online)
As more and more different soft tissue filler agents flood the market, physicians must become knowledgeable about the qualities, indications, risks, and various injection techniques of each agent prior to injection. It was much simpler when only a few injectables were available. But now, we are besieged by many types of filler, competing against each other with salesmen and companies touting the superiority of their particular substance. The physician must recognize that the agents are not interchangeable and must individualize the therapy based on each patient's individual needs. The younger surgeon is quick to embrace new technology for his patients but must only do so carefully so as not to harm the patient. For example, when Radiesse® (formerly Radiance™) first appeared, it seemed to be a great solution to the relatively short longevity of most fillers with a promise of 2 to 5 years. Many started injecting it into nasolabial folds, which was fine because it could be placed deeply and minor irregularities would not be visible. But some surgeons, to make bigger lips last longer, started injecting it into lips. The problem became quickly apparent as the lips are so thin-there's not much between the muscle and the skin. Bumps appeared that were not only palpable but also visible. Patients became angry and disappointed, and some physicians had to surgically remove the bumps. Similarly, when we all became more cognizant of the tear trough deformity, many rushed to inject fat or hyaluronic acid into the lids. But some injected too superficially, and lumps appeared. Each filler has its own particular level for injection, which varies from one facial area to another. When injecting agents for deeper placement, one needs to be careful not to inject all the way on the way out so as not to deposit the material too superficially and cause a long-lasting bleb. The same technique does not work everywhere, and physicians must continue to learn about the specifics of each agent before using it.
All physicians must recognize that patients believe what they read in Vogue, Elle, and Cosmo, despite the fact that what appears in these “lay medical journals” is often just the product of a vigorous advertising agency hired by the manufacturer and is not subject to peer review. There may be liabilities in using products that are not yet approved for a particular use, especially when there are no scientific data to back up a particular use. For example, poly-L-lactic acid is, at the time of press, only approved for use in HIV patients, although many physicians have been using it reportedly without problems in a more dilute form in non-HIV patients. Fortunately for those of us in the United States, many of the newer soft tissue fillers have first been used in Canada and Europe and so we can learn from our foreign colleagues what the long-term effects and problems are. The reluctance of our Food and Drug Administration to approve substances too easily might be saving us many problems seen in other countries. For example, do we really want to inject methylmethacrylate beads into lips, when we know the effects are forever? We need to just read the literature to see the effects of permanent fillers like silicone and extrapolate that experience to the current offerings. Bodies and faces change with the years and a permanent filler may not be appropriate in certain areas as they morph with age. At the same time, we need to constantly search for replacements for our current fillers when superior alternatives appear. It is rare for us to use a bovine collagen filler now, whereas 10 years ago that was our number one agent. With hyaluronic acid fillers, longevity is increased and allergic responses are almost nonexistent. But we have lost the combination of a lidocaine mixture in the filler, so we must use topicals and sometimes blocks, and so other skills and facts must be learned. We no longer use micronized acellular dermis (Cymetra®, which is cut-up Alloderm®) as an injection now either: it is difficult to mix and offers little advantage over hyaluronic acid. Newer formulations of hyaluronic acid as they are released in the United States will afford us the ability to treat different types of wrinkles and folds. We do use calcium hydroxylapatite microspheres for deep nasolabial folds and volume replacement deep in the face in certain patients who want longer-term results. We use hyaluronic acid throughout the face and lips for many indications, and we continue to use fat injections for bulk and volume. For long-term lip enhancement, we still will surgically place rolls of acellular dermis because of its natural feel when healed.
In summary, we must continue to learn as new fillers come to the market and use our knowledge and that of our colleagues to safeguard patients and produce the best results we can. We must look critically at all newcomers and apply basic principles as we examine the new science.