Abstract
BACKGROUND: Botulinum toxin has been widely accepted as safe and effective for the treatment of glabellar lines, and previous studies have classified glabellar contraction patterns into 5 categories. OBJECTIVE: To classify the glabellar contraction patterns among a large-scale Chinese population and provide a reference for injections in Chinese patients. METHODS: Four hundred eighty-nine Chinese subjects who received botulinum toxin for the treatment of glabellar lines were selected for a retrospective photographic analysis of their glabellar contraction patterns. Using 2 separate previously established classification systems, the patterns were analyzed and classified by a panel of certified Chinese dermatologists. RESULTS: Two separate classification systems showed different distributions of glabellar contraction patterns among Chinese compared with Caucasians and Koreans. The classifications allowed for identification of the most frequent patterns in Chinese, which were "converging arrows" and "11" pattern, and provided references for identifying the most important muscles. CONCLUSION: Both classification systems are applicable to the Chinese population with varying distributions. Because the classification system of de Almeida and colleagues focuses more on the muscles involved in the formation of glabellar lines, the authors' subjects classified according to this system displayed a more balanced distribution among the 5 patterns. This provides an easier reference for dermatologists in daily clinical practice and guiding treatment strategies.