Prevalence of transverse upper labial crease

Abstract

Background

The presence or hyperactivity of the depressor septi nasi muscle has been proposed to cause a visible crease in the upper labial region that is esthetically disturbing to patients. The objective of this paper was to determine how often an upper labial crease is evident in women and to find a straightforward treatment. Muscular creases can be ameliorated with botulinum toxin. However, weakening the depressor septi nasi muscles with botulinum toxin did not eradicate existing upper labial creases at rest or during facial animation. Therefore, we proposed that a complex interplay exists between the upper labial muscles, and we sought to determine which of these muscles are responsible for the existence of the upper labial crease.

Methods

A total of 100 consecutive female volunteers who visited a plastic surgery clinic were prospectively examined. The presence and localization of the upper labial crease were assessed at rest and during animation prompted with the "smile test" and during snuffling. Additionally, the appearance and symmetry of the upper labial crease were assessed and correlated with the type of smile to identify the dominant muscles involved.

Results

In total, 38% of women older than 40 years presented with an upper labial crease at rest, and 70% presented with a crease during animation. Only one third of the women were aware that they had such a crease when they smiled. When the crease was present, it was bilateral in 98% of the women. When it was asymmetrical, which was the case for 10% of women, the fold was longer, shorter, or less visible on one half of the upper lip. The localization was highly variable and ranged from the base of the columella to the caudal third of the upper lip. When an upper labial crease was present at rest and/or during facial animation, it was associated with a type B smile, i.e., the "canine" smile, due a dominant levator labii superioris muscle.

Conclusions

This study showed that upper labial creases are present more often than women are aware of them. The injection of botulinum toxin into the levator labii superioris muscles can eradicate an upper labial crease.

Level of Evidence: Level IV, risk / prognostic study.

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