Dermal fillers have been used to improve the loss of facial volume for more than 20 years, although with the new products, this cosmetic procedure has undergone significant development in recent years, especially when used for lip augmentation1 or to restore volume of nasolabial folds, marionette lines, and dynamic wrinkles of the upper face.2 Presently, it is considered the second most popular medical cosmetic procedure in the United States.3 Although the techniques and materials are relatively safe, the number of undesirable effects reported has increased each year.
Permanent fillers are responsible for most of the reported side effects, while resorbable materials are safer. In our experience, the best resorbable material for soft tissue implantation is hyaluronic acid (HA) of nonanimal origin with a medium density (HAMD), which can be present with a high or low grade of reticulation, the last known as nonanimal stabilized HA (NASHA).4 A recent comparative study conducted by Brandt et al5 found that both small and large gel-particle HA are safe and effective in facial rejuvenation, but a new HA-based dermal filler Uma Jeunesse that uses a new cross-linking technology was shown to be safer and to have a higher longevity in skin tissue than JuvÃ©derm.6 HA filler longevity seems to be related to the different resistance to hyaluronidase and/or free radical degradation in the different products, according to their physical properties,7 and the knowledge of this characteristics allows physicians to choose the appropriate product for each patient according to their expectations and needs.8 The adverse events (AEs) can be classified according to their onset time. Immediate-onset reactions appear in the first 24 to 48 hours after the filler injection and include vascular obstruction, reactions associated with the injection technique (erythema, edema, hematoma, pain, or tenderness),9 hypersensitivity reactions, and skin discoloration. Early-onset AEs appear within 14 days after injection and usually consist of transient reactions and infections. Late-onset complications develop more than 14 days after the injection and can present in the form of delayed hypersensitivity, product migration, nodules, and granulomas.10-12 The majority of AEs are related to inadequate injection technique, mostly at an inappropriate depth. The best level for HAMD injection is the mid or deep dermis; collagen should be injected into the reticular dermis, calcium hydroxyapatite and tricalcium phosphate in the transition between the dermis and subcutaneous tissue, and fat and polylactic acid in the subcutaneous tissue.
In this situation, we decided to evaluate the complications of soft tissue augmentation with nonanimal reticulated or stabilized HA observed in our cosmetic unit in the past 3 years.
MATERIAL AND METHODS
We reviewed consecutive patients who presented to our cosmetic unit in the past 3 years complaining about AEs associated with absorbable fillers for soft tissue augmentation, concretely HA. All patients received the filler injection outside our clinic.