Evaluation of botulinum toxin A injections for the treatment of glabellar lines by using high-frequency ultrasound / 中华皮肤科杂志

ABSTRACT

Objective To investigate changes in thickness of the skin and muscular layer during the treatment with botulinum toxin A injections in patients with glabellar lines.Methods Twenty-six subjects with moderate to severe glabellar lines were enrolled into this study,who received botulinum toxin A injections in Peking Union Medical College Hospital from August 2017 to February 2018.Before the injections,4 and 16 weeks after the injections,thickness of the dermis at the injection site was measured by using 50 MHz high-frequency ultrasound,and full thickness of the skin and thickness of the muscular layer were measured with 20 MHz high-frequency ultrasound.Repeated measures analysis of variance,paired ttest and Bonferroni method were used to compare the pretreatment and posttreatment tissue thicknesses measured by using high-frequency ultrasound.Results Before the injections,the thickness of the dermis,full thickness of the skin,thickness of the muscular layer were 2.01 ± 0.48,4.32 ± 0.73 and 4.51 ± 0.67 mm respectively.No significant difference was observed among the pretreatment,4-and 16-week posttreatment thickness of the dermis (F =1.94,P =0.199),while there were significant differences among the pretreatment,4-and 16-week posttreatment full thickness of the skin and thickness of the muscular layer (F =6.28,24.19,P =0.020,＜ 0.001 respectively).Four weeks after the injections,the full thickness of the skin significantly increased (4.88 ± 0.93 mm,t =3.72,P =0.004),while the thickness of the muscular layer significantly decreased (3.82 ± 0.79 mm,t =4.65,P =0.001)compared with the pretreatment thicknesses.Sixteen weeks after the injections,the full thickness of the skin (4.61 ± 0.73 mm) and thickness of the muscular layer (4.38 ± 0.90 mm) did not significantly differ from those before and 4 weeks after the injections (all P ＞ 0.016 7).Conclusions Botulinum toxin A injections can change the thickness of the subcutaneous tissue and muscular layer.High-frequency ultrasound can be applied to the evaluation of efficacy and to follow-up after the treatment of glabellar lines with botulinum toxin A injections.