The Relationship Between Glabellar Contraction Patterns and Glabellar Muscle Anatomy: A Magnetic Resonance Imaging-based Study.

Abstract

Glabellar contraction patterns were introduced to the scientific literature to help guide glabellar neuromodulator injection algorithms. However, the relationship between the underlying musculature and its influence on these glabellar contraction patterns is unclear. The aim of this study was to identify via Magnetic Resonance Imaging (MRI) glabellar muscle parameters that display an influence on the distribution of individual glabellar contraction patterns. Thirty-four healthy young individuals of Caucasian Polish descent were investigated (17 women, 17 men) with a mean age of 23.6 years and a mean BMI of 22.8 kg/m2. MRI-based measurements of length, thickness, width and surface area of procerus, corrugator supercilii, orbicularis oculi and frontalis muscles were conducted. Unadjusted models revealed that there was no statistically significant difference between the five glabellar contraction types and the investigated muscle parameters indicating that independent of the skin rhytid pattern, the underlying musculature was not different between the investigated groups in this sample with all p ≥ 0.102. Adjusted models revealed that sex was the most influential factor due to males displayed in general higher values for the investigated parameters when compared to females. The results of this study reveal that based on the MRI parameters investigated and based on the investigated cohort, there does not appear to be a strong relationship between glabellar contraction patterns and underlying glabella muscle anatomy. Utilizing glabellar contraction patterns to design neuromodulator treatment algorithms may be of variable clinical merit.