BACKGROUND. Several biomaterials are available for the purpose of soft tissue augmentation, but none of them has all the properties of the ideal filler material. The recent development of hyaluronic acid gels for dermal implantation give the physician neu, possibilities of effective treatment in this field. OBJECTIVE. This study provides a clinical and histological evaluation of safety and efficacy of a cross-linked stabilized nonanimal hyaluronic acid gel (Restylane, Q-Med, Uppsala, Sweden) to determine its characteristics, advantages, disadvantages, and side-effects. METHODS. 158 patients were treated with facial intradermal implant of hyaluronic acid gel for augmentation therapy of wrinkles and folks, and for lip augmentation and/or recontouring. The results were evaluated in all patients by subjective judgement by the physician aim the patient, and by photographic method at time 0 and after 1, 2, 4 and 8 months from the procedure. In addition, a smaller histological study was carried out in five volunteer patients for a term of 52 weeks to determine the interaction and duration of the material ill human healthy skin. RESULTS. Clinically, both the physicians' and patients' evaluations revealed very satisfactory results, with a global 78.5% and 73.4% respectively of moderate or marked improvement after Eight months, independent of the treated area. The photographic evaluation revealed even better results with a 80.4% of moderate or marked improvement after 8 months. The safety evaluation showed a 12.5% of postoperative immediate adverse events, that were localized and transient. There was no evidence of major systemic sine effects. Histologically, the product was shown to be long-lasting and well tolerated as judged by histological techniques. CONCLUSIONS. Stabilized, non-animal, hyaluronic acid gel is well tolerated and effective in augmentation therapy of soft tissues of the face. This material presents several advantages in comparison to previously used injectable biomaterials and expands the arsenal of therapeutic tools in the field of soft tissue augmentation. (C) 1998 by the American Society for Dermatologic Surgery Inc.
