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According to the degree of cross-linking, more or less dense, moldable and resistant products will be obtained.
It has a high moisturizing power, is able to stimulate the production of collagen in the dermis and thus contributes to improve skin elasticity. Hyaluronic acid (HA), as a synthetic, biodegradable and biocompatible product (and derived from non-animal hyaluronic acid) is used in aesthetic medicine for a series of treatments ranging from hydration to lip augmentation or repositioning of lost volumes. However, thanks to the cross-linking process, there are currently different types of hyaluronic acid on the market that are adaptable according to the tissue to be treated.
As Dr. Martha Napoleone, a member of EIMEC’s professional team and a specialist in Regenerative Facial Aesthetic Medicine, explains, “the cross-linking process consists of creating links between several chains of hyaluronic acid – which in its pure form is formed by linear chains and, therefore, would be in liquid form – with a synthetic product called butanediol diglycidyl ether (BDDE), finally achieving a product in the form of a gel. “According to the degree of cross-linking, products with different rheological characteristics will be obtained [rheology is the science that studies the behavior of hyaluronic acid in a tissue through the study of elasticity, viscosity, water uptake and AH/mL centration, among others]; that is, products that are more or less dense, moldable and resistant”. In other words, this means that there is a wider range of possibilities when it comes to injecting the product for a given anatomic plane. In addition, the expert adds, the choice goes hand in hand not only with the area to be treated but also with the result sought.
For this reason, the specialists insist, a prior assessment of each patient is a key step. “The diagnosis must be focused on the anatomy and pathophysiology of aging. For example, for volume repositioning, the anatomical plane to be treated will be a deep supraperiosteal plane, for which a highly cross-linked hyaluronic acid should be used. In this way, support, firmness and greater durability are guaranteed,” says Napoleone. In the case of treating areas of greater mobility, such as the lips, for example, where it is also necessary to work on the superficial plane, the product selected will be a hyaluronic acid of medium or low cross-linking to ensure greater moldability and adaptation to the tissue.
Dark circles under the eyes and fine wrinkles
To treat dark circles under the eyes, on the other hand, it will be essential to choose a product specifically suitable for this anatomical area. And in the treatment of subdermal redensification, hydration and treatment of fine wrinkles, the choice of product will go more towards a low cross-linking hyaluronic acid, the injection plane being more superficial.
-Is there a consensus on application protocols?
Generally speaking, yes,” says Napoleone. It is already a basic rule for aesthetic physicians to perform treatments that focus on the anatomy of the face with a protocolized approach. This is based on a functional division of the face, which implies an initial support to a portion posterior to a defined line of retaining ligaments, which is defined as the fixed portion, and then an approach of the middle portion to that line (mobile portion) for projection. Napoleone adds that more and more work is being done with multilayer techniques in different anatomical planes and with different types of hyaluronic acid, according to the principle of facial aging, which is a multifactorial process that involves all the structures that characterize it.
As for the complications derived from these non-surgical procedures with HA, the specialist warns that there may be unwanted effects and risks, as is the case with any type of treatment. “Every procedure has its risk. Fortunately, serious complications such as ischemia or tissue necrosis due to vascular compromise due to direct infiltration of the artery, or due to compression, are not very frequent. But they are possible,” he says.
The most frequent complications, he describes, are given by the formation of nodules or Tyndall effect due to injection in an unsuitable plane (generally superficial), migration of the product, granulomas or late inflammation. “That is why it is important for each esthetic physician to have a thorough knowledge of the anatomy and pathophysiology of aging, as well as the characteristics of the products used to choose the most appropriate for a given anatomical plane and tissue.” Also, suggests Napoleone, it is essential to communicate well with the patient prior to treatment, to sign the informed consent form and, above all, to follow up with the patient, just as happens in the various medical practices in other branches of medicine.
“The patient must know and feel that he or she is dealing with a qualified, certified professional who has studied for this,” concludes the expert.
