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Efficacy and Safety of Polyacrylamide Hydrogel for Facial Soft-Tissue Augmentation

Background: Polyacrylamide is a nonabsorbable soft-tissue filler that has been used for body contouring for more than 10 years. Aquamid is a soft-tissue filler containing polyacrylamide hydrogel. Safety and aesthetic results after injection of polyacrylamide hydrogel for facial soft-tissue enhancement were assessed at a 1-year follow-up. Methods: In a prospective, multicenter study, 251 patients were enrolled and assigned for injection of polyacrylamide hydrogel (Aquamid) as a means of facial augmentation and enhancement of facial contours. Subjects with facial contour deformities or soft-tissue deficiencies caused by aging, acne, trauma, surgery, or other causes were included. Persons presenting with connective tissue disorders, skin disorders affecting the face, uncontrolled diabetes mellitus, compromised immune functions or acute inflammatory diseases, known substance abuse, or mental disorders were excluded from participation in the study, as were those who had experienced treatment with any nonabsorbable filler within 6 months before the start of the study. To assess the safety and efficacy of the treatment, follow-up visits were scheduled for day 7, day 28, and 3 months, 6 months, and 12 months after the first injection. Standardized photographs were taken before treatment and during month-3 and month-12 visits. Blood and urine samples were collected and analyzed before injection and at 6 and 12 months after injection. The most common sites of injection were the nasolabial folds (48 percent) and lips (25 percent) followed by glabella folds (8 percent) and other sites. The amount of injected gel ranged from 0.2 to 12 ml. Results: Two hundred twenty-eight patients were followed for 12 months after treatment. In 93 percent, results were judged to be good or very good by the investigators and satisfactory or very satisfactory by the patients. Adverse events that could be ascribed to the treatment were observed in 37 cases, most commonly presenting as transient swelling, hematoma, redness, and pain or itching. In one case, a slight change of skin color at the site of injection was reported. No severe adverse events related to the gel were observed. In one case, neutropenia was detected in month-12 blood samples. The other values were within the normal ranges. Conclusions: Aquamid is an easy-to-use soft-tissue filler. The effect of tissue enhancement lasted over the entire study period. Transient local tissue reactions observed were attributable to the injection procedure rather than the chemical properties of the gel. During the first year after treatment, no permanent soft-tissue reaction was observed. Long-term results need to be evaluated in the future.