INTRODUCTION
Facial rejuvenation procedures, which are minimally invasive
and provide a long-lasting visible improvement, are rapidly increasing in popularity.1,2 In recent years, the recognition that facial volume loss plays an important role in the aging process, has shifted the focus of treatment from a concentration on isolated problem areas to targeting the entire face for a more harmonious and natural effect.3-5 Dermal fillers give the face a fuller, more youthful appearance and have become a popular means of addressing volume loss and contour defects resulting from ageing, disease, or trauma. As their popularity increases, so too has the number of products available. However, regulation of the industry varies considerably between countries. Pharmaceutical products achieve their principal action by pharmacological, metabolic or immunological changes within or on the body. Dermal fillers are classified as medical devices by most regulatory agencies, including the US Food and Drug Administration (FDA) as their primary intended action is mechanical (filling effect) and not pharmacological.In Europe, dermal fillers are also considered as medical devices, but they only require a European CE Mark that does not demand the conduction of clinical studies for approval to commence sales. In contrast, prescription only medicines such as botulinum toxin require a marketing license from the Medicines and Healthcare products Regulatory Agency (MHRA). In the USA, FDA approval is based on the review of data collected from controlled clinical studies of at least 6 months duration that have evaluated the safe and effective use of dermal fillers when injected into specified areas of facial tissue and in comparison
with an established FDA-approved agent.
Benefit versus safety is a key consideration for any therapeutic
product. Calcium hydroxylapatite (CaHA [Radiesse®]; Merz Pharmaceuticals GmbH, Frankfurt, Germany) received FDA approval in 2006 for facial soft tissue augmentation including the correction of moderate to severe nasolabial folds, and the restoration and correction of the signs of HIV-associated facial lipodystrophy. In Europe, CaHA received a CE mark in 2004 for plastic and reconstructive surgery, including deep dermal and subdermal soft tissue augmentation of the facial area. Since then it has been extensively used for the correction of moderate to severe facial lines and folds and to replenish lost volume. It is one of the most well-studied dermal fillers with more than 4 million syringes injected worldwide. This paper focuses on common safety concerns of patients and aesthetic physicians, including unfounded fears of osteogenesis and foreign body granulomas, providing an up-to-date overview of the tolerability and long-term safety of CaHA for aesthetic indications.
Mechanism of Action
CaHA is a biodegradable filler composed of synthetically produced
smooth, uniform CaHA microspheres (diameter of 25-45 μm) suspended in a sodium carboxymethylcellulose gel carrier combined in a ratio of 30% microspheres to 70% gel by volume. The gel carrier suspends the particles and allows them to be de-
