Hyaluronic acid fillers and botulinum toxin type a: rationale for their individual and combined use for injectable facial rejuvenation

Abstract

Soft-tissue augmentation has seen a renaissance of interest, as an increasing number of patients seek aesthetic improvement without major downtime. Although injectable agents for soft-tissue augmentation have been widely available for more than 20 years, the renewed interest has been fueled in part by the introduction of botulinum toxin type A. The unequivocal establishment of predictable and aesthetic results, initially and primarily in the upper face, created a need for an agent that would work equally well in the lower face and that could be administered in an office setting. The marriage of these two injectables (hyaluronic acid and botulinum toxin type A) began with the escalating popularity of both of these substances individually and the realization that a more global aesthetic enhancement is provided by combining these agents in custom proportions to achieve maximum aesthetic effects. Although the authors discuss most of the related, available hyaluronic acid and botulinum toxin agents, their clinical experiences, and the scientific data regarding these products, they realize that the discussions have been weighted toward the products that have been available for use in the United States the longest. In this article, they attempt to explain some of the results of prior (to U.S. Food and Drug Administration approval) studies that have been the subject themselves of some confusion, and provide a rationale for using hyaluronic acids and botulinum toxin for facial enhancement independently and in combination.