Abstract

Botulinum neurotoxin type A (BoNT-A) injection for lateral canthal rhytids is among the most frequently performed nonsurgical aesthetic procedures; however, procedure-related hematoma and ecchymosis remain frequent local adverse events associated with the multiple puncture sites required in the conventional three-point technique. This prospective single-center preliminary clinical observation evaluated a single-point intramuscular injection technique designed to reduce percutaneous vascular-layer penetrations while preserving treatment territory, dose, and intramuscular target localization. A total of 152 consecutive patients (104 female and 48 male) underwent bilateral treatment between May 2025 and May 2026 using a single skin entry point per side, positioned 10–15 mm caudal to and 10 mm temporal to the lateral canthus, followed by 18–20 mm intramuscular advancement within the lateral orbicularis oculi and continuous retrograde infusion of 12 U of onabotulinumtoxinA per side. Post-procedural assessment after injection demonstrated small unilateral ecchymosis in 2 of 304 treated sides (0.66%; Clopper–Pearson 95% Confidence Interval (CI), 0.08–2.36%). After the 10-day follow-up, no persistent bruising or other adverse events were reported, and all patients confirmed satisfaction with the treatment. At the structured one-year follow-up, the satisfactory reduction in dynamic lateral canthal rhytids and continued patient satisfaction with the treatment were confirmed, while a subset elected to return for a subsequent treatment session during the observation period. By reducing bilateral percutaneous venous-layer penetrations from six to two while maintaining dose and treatment-territory equivalence, the single-point intramuscular technique may represent a structurally coherent refinement of established BoNT-A treatment concepts for lateral canthal rhytids. Because this was an uncontrolled preliminary clinical observation, the observed rate should be interpreted as descriptive only; any potential reduction in hematoma risk remains hypothetical.

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