Muscle Insertion and Strength of the Muscle Contraction as Guidelines to Enhance Duration of the Botulinum Toxin Effect in the Upper Face.

[BACKGROUND] In this series of patients the cutaneous insertion and strength of voluntary contraction of the muscles in the upper third of the face were used as guidelines for botulinum toxin application named "BTA Codes."

[METHOD] Anatomical dissection of fresh cadavers identified the shape and cutaneous insertions of the muscles in the upper third of the face. Patient voluntary contraction of the muscles in the upper third of the face created different patterns of skin lines classified by the 4-grade Facial Wrinkle Scale. For botulinum toxin application injections points followed the muscle cutaneous insertion and dose the 4-grade Facial Wrinkle Scale.

[RESULTS] Injection points ranged from 3 to 23 points per patient, average of 9.4 points. Dose per point varied from 2.5 to 7.5 U, ranging from 12.5 to 72.5 U per patient, average of 33.82 U. Skin lines resulting from the voluntary contraction of the muscle prior to toxin application were stated as baseline 1. The absence of skin lines and muscle activity on day fifteen after toxin application defined baseline 2. Skin lines resulting from the recovered voluntary contraction of the muscle after toxin application like those of baseline 1 established baseline 3. The botulinum toxin effect was the time elapsed between baselines 2 and 3, ranging from 171 to 204 days, average of 183.72 days, greater than the 3 or 4 months reported in the literature.

[CONCLUSION] "BTA Codes" is a set of rules to apply botulinum toxin supported by muscle anatomy and degree of voluntary contraction to enhance the duration of its effect.

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