Refining injection techniques

Lateral canthal rhytids treated with three injections of abobotulinumtoxinA (Dysport, Medicis) showed no statistically significant difference from those treated with one injection, according to a study in the August issue of the Journal of Drugs in Dermatology.

The split-face study included 40 patients with moderate-to-severe hyperdynamic lateral canthal rhytids at maximal contracture who received one injection of 36 units of abobotulinumtoxinA into the middle of the lateral orbital rhytids on one side and three intradermal injections of 12 units each along the lateral canthal area on the contralateral side, according to the abstract. A blinded evaluator examined lateral orbital rhytids at rest and maximal contraction at baseline, seven, 42, 90, and 120 days post-treatment.

Reducing the number of injection sites can improve patient comfort during treatment and potentially decrease risk of bruising, according to Hema Sundaram, M.D., a Washington dermatologist and cosmetic surgeon in private practice and one of the researchers.

Ability to reduce the number of injection sites is a manifestation of enhanced spread of BoNT-A, which depends on factors including dosage, dilution (reconstitution volume) and injection technique, she says. What’s important is that evidence level 2 studies have shown that spread is not a clinical problem for any of the available injectable BoNT-A products. Each one is comparable in safety and efficacy. Specifically, the incidence of upper eyelid ptosis after glabellar injection - an indicator of undesirable spread - is low and comparable for all three products.

“Studies like this one on reduction of injection sites help us to refine our techniques with BoNT-A and thereby apply individualized treatment strategies based on an understanding of what is happening functionally and how we can best correct it. It’s a step forward that allows us to optimize treatment results for all our patients,” Dr. Sundaram says.

Disclosures: Dr. Sundaram serves as a clinical investigator and/or consultant for Allergan, Ipsen, Medicis/Valeant, Mentor/Johnson & Johnson, Merz and QMed/Galderma.

Reference: Fabi SG, Sundaram H, Guiha I, Goldman MP. A two-center, open-label, randomized, split-face study to assess the efficacy and safety of one versus three intradermal injection sites of abobotulinumtoxinA in the treatment of lateral periocular rhytids. J Drugs Dermatol. 2013;12(8):932-937

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