When using the Restylane Treatment Plan for the treatment of nasolabial folds with Restylane injectable gel, 94% of patients in clinical studies maintained results for up to 36 months from initial treatment when they had a follow-up treatment at 4.5 months or 9 months and 18 months. The maintenance of results using Restylane-L, Restylane Fine Lines, Perlane and Perlane-L injectable gels has not been studied. Data on file, Medicis Pharmaceutical Corporation. more... See more text