The use of hyaluronic fillers in the field of aesthetic medicine is a worldwide trend. This can correct what many perceive as blemishes associated with aging skin. However, there are a few things to keep in mind for safe and successful filler treatment.
The American Society for Aesthetic Plastic Surgery recorded over 720,000 procedures in the United States in 2017, an 85% increase from 2012 [1]. Over the years, hyualuronic acid treatments have become increasingly effective and the safety profile has greatly improved. Nevertheless, the application is associated with certain risks.
Minimization of possible side effects is central
The increasing use of fillers in aesthetic treatments worldwide is also accompanied by reports on potential complications of this procedure. Adverse effects may occur immediately after treatment, with some delay, or later in the course. Possible side effects immediately following treatment include hematoma, swelling, and vascular damage. Adverse effects occurring with a delay of up to two weeks include allergic and bacterial reactions. After an interval of more than three weeks, inflammatory late reactions are possible. Most of these complications resolve on their own after some time, but some are irreversible. Not long ago, a multidisciplinary group of experts published consensus recommendations in the journal Aesthetic Plastic Surgery, based on an extensive literature review [2]. The authors conclude, among other things, that emergency scenarios and the equipment required to treat corresponding complications are an important factor in ensuring that the extent of possible consequential damage is as low as possible.
Topical nitroglycerin for the treatment of necrosis?
Laurence Imhof, MD, Head of the Department of Aesthetic Dermatology and Physical Therapies at the University Hospital Zurich, presented several recent studies on the management of side effects at this year’s Zurich Dermatology Training Days [3]. A secondary analysis published in 2020 evaluated the benefit of nitroglycerin in preventing or containing tissue necrosis using a variety of trial data [4]. What is the conclusion of this publication? “That at best, nitroglycerin has a synergistic effect with other treatments used for filler necrosis. That is, it can be used as an adjunct with hyualuronidase injections. Because it has been used mainly in combination, it is not possible to identify a direct effect of topical nitroglycerin in filler necrosis,” the speaker summarized. Unfortunately, the level of evidence of the studies evaluated in this secondary analysis is rather low, Dr. Imhof adds. Necrosis is a rare complication that can occur when the filler cuts off the vascular supply. This is due to extravascular compression, damage to the vessel, and intra-arterial filler emboli. Patients who have undergone rhinoplasty in previous years appear to be at increased risk for tissue necrosis [5].
Important product features
|
Rheological properties are crucial
Hyaluronic acid fillers are the most commonly used fillers to correct wrinkles on the face. Hyaluron is a long-chain, linear polysaccharide found in many tissues that performs primarily mechanical, but also biochemical-physiological functions. Hyaluron molecules are highly hydrophilic and not tissue specific. Since they also have only low immunogenicity and treatments with hyualuronic acid are reversible in principle, it is a suitable filling material. Since free hyualuron chains have a short biological half-life in vivo, chemical stabilization by cross-linking is required for use as a filler. The biomechanical properties of commercially available fillers can vary considerably. Given the wide range of products, selecting the appropriate preparation can be a major challenge. The face, as a dynamic structure, is also affected by mechanical forces acting on the various anatomical regions during rejuvenation procedures, involving a combination of shear, compression, and tensile forces. Successful use of fillers takes these components into account and requires knowledge of the available options. “It is essential to compare the rheological properties of the products,” she said. In a study by Lee et al. [6], the rheological properties of various hyaluronic acid fillers available on the market were measured to explain how the products should be optimally used, taking into account their rheological properties. A total of 41 hyaluronic acid fillers were analyzed for their injection properties, such as hyaluronic acid concentration or particle size, and rheological properties, and compared with the manufacturer’s specifications. The authors were able to show from their measurements that products from different manufacturers used for the same indication sometimes exhibit large differences in their rheological properties. This can be explained by the technological process used by the manufacturers for the different fillers, which in turn can affect their molecular structure and also clinical performance. G’ is a measure of the capacity of a gel to resist a defined load. The greater this value, the higher the resistance to deformation, it affects the stiffness of a product. A comparison of G’ of different products shows that there is considerable variation with regard to this property. From this it can be deduced that the clinical performance of different fillers is different, even if they are used for the same indication. The subcutaneous products Restylane Sub Q®, Neobelle® Contour and Yvoire® Contour have high G’ values. This means that they are stronger and have a lower tendency to deform. Therefore, these products are particularly suitable for contouring or modeling deeper areas, for example, the chin. Products with lower G’ values may also be suitable, but are more likely to diffuse into the tissue. The speaker summarizes the conclusion of this study as follows: “Similar fillers from different manufacturers can differ greatly in their rheological properties, even though they are advertised for the same indications. It is therefore fundamental to understand the rheological properties of a product in order to make the right choice and thus have satisfied customers in the long term,” Dr. Imhof emphasizes.
Source: ZDFT 2020
Literature:
- American Society for Aesthetic Plastic Surgery (ASAPS): Cosmetic surgery national data bank statistics. www.surgery.org
- Urdiales-Gálvez F, et al: Treatment of Soft Tissue Filler Complications: Expert Consensus Recommendations. Aesthetic Plast Surg 2018; 42(2): 498-510.
- Imhof L: What’s new in Aesthetic Dermatology? Laurence Imhof, MD, Zurich Dermatology Continuing Education Days (ZDFT), May 14-15, 2020.
- Carley SK, et al: Nitroglycerin, or Not, When Treating Impending Filler Necrosis. Dermatol Surg 2020; 46(1): 31-40.
- Robati RM, et al: The Risk of Skin Necrosis Following Hyaluronic Acid Filler Injection in Patients With a History of Cosmetic Rhinoplasty. Aesthet Surg J 2018; 38(8): 883-888.
- Lee W, et al: Practical Guidelines for Hyaluronic Acid Soft-Tissue Filler Use in Facial Rejuvenation. Dermatol Surg 2020; 46: 41-49.
DERMATOLOGIE PRAXIS 2020; 30(4): 42-43 (published 8/24/20, ahead of print).
