Some fillers can have quite long-lasting effect (up to 10 years). Called permanent or semi-permanent (non-biodegradable) they are gels based on synthetic polymers. Synthetic products are the most unfavorable in terms of the number and severity of side effects. They can be used in case of presence of large post-traumatic defects, with lipoatrophy in HIV-infected patients and in some cases in patients in adulthood (i.e. after 55 years), when the intensity of metabolism decreases and so does the risk of complications.
Let’s have a look at Polymethyl-methacrylate microspheres, permanent injection filler Restylane with a two-phase structure for soft tissues. PMMA is composed of a solid phase made up of polymethyl-methacrylate (PMMA) microspheres with a smooth surface (25%) suspended in a partially denatured bovine collagen (75%) solution used as a carrier gel. Due to the absence of immunogenic telopeptides, collagen molecules become less allergenic.
Perfect candidates for the injection of PMMA are patients with visible wrinkles and folds, post-acne scars and other obvious soft tissue defects associated with the presence of excess skin. The filler is injected subdermally, followed by a light massage of the injection area to avoid the formation of tubercles and uniform distribution of the filler. Within a few days after the introduction of PMMA, the patient should avoid high activity of facial muscles
The frequent and severe side effects of polymethyl-methacrylate include redness, swelling and soreness, which usually occur within the first two days after the procedure. Bruises after PMMA injections are rare, also during the first months after the procedure, itching may occur.
Side effects associated with the technique of PMMA injection include uneven distribution of excessive filler volume and its migration due to excessive muscle activity.
Clinical complications include the formation of seals and nodules within 3-24 months after the injection of PMMA. Some experts believe that the reason for this is superficial quantity of the drug or uneven inflammatory response, leading to the formation of granulomas and hypertrophic scars. In such cases therapy is carried out with the help of corticosteroid injections which reduce the activity of fibroblasts and macrophages and thereby prevent the formation of collagen deposits and abnormally large cells.
Only surgical treatment of these complications is possible.