Botulinum Toxin A for Lower Facial Contouring: A Prospective Study

Excerpt

This article, on the surface, appears similar to other articles describing the effects of botulinum toxin type A on masseter muscles to improve facial contour. Other articles, as the authors duly note, have been written about this technique previously. The technique has, in fact, become rather commonplace. I have injected the masseters of more than 100 patients since 1992, with slight variations in the technique. However, one thing had always bothered me about the technique: Why was it that the cosmetic result seemed to last almost twice as long in the masseter as in, say, the glabella, forehead, crow’s feet, or other lower facial musculature at the first injection (which rules out long-term atrophy as the cause)? I had always entertained a theory to explain why this was so, but certainly no objective proof. The fact that the effect of botulinum toxin type A on axillary hyperhidrosis lasted significantly longer than that of cosmetic denervation techniques had never bothered me. The end organs (muscle and eccrine glands) were completely different. But why should effects on the masseter differ so greatly from a temporal standpoint than, say, the effects on the glabella? If anything, longer-lasting results might be expected in the glabellar region because the clinician often completely paralyzes the area, leaving no apparent functioning muscle. To my knowledge, no one advocates completely paralyzing the masseters, yet the results are surprisingly long lived. …