Accessing the Levator Labii Superioris Alaeque Nasi (LLSAN) Muscle for the Treatment of Infraorbital Dimples-A Case Report.

[BACKGROUND] Medial infraorbital dimples are dynamic soft tissue depressions that can emerge or intensify following neuromodulator treatment in the periorbital region. Rather than being congenital or structural in origin, these dimples often result from imbalanced facial muscles most notably the levator labii superioris alaeque nasi (LLSAN).

[OBJECTIVE] To elucidate the pathophysiology of a medial infraorbital dimple arising after botulinum toxin injection into the lateral orbicularis oculi muscle (OOM) and to demonstrate the clinical efficacy of a targeted neuromodulator injection into the LLSAN muscle.

[CASE SUMMARY] We present a case involving a 31-year-old female who developed a prominent medial infraorbital dimple four weeks after receiving a cosmetic botulinum toxin injection for her crow's feet. This dimple was most prominent during smiling. A single, superficial injection of 2 units of botulinum toxin type A into the LLSAN led to substantial aesthetic improvement, starting 2 days after the treatment with preserved natural expression and no functional deficit.

[CONCLUSION] Recognition of compensatory muscular activity and intramuscular injection of neuromodulators for the LLSAN offers a safe and effective approach for treating medial infraorbital dimples while preserving facial harmony.