title: Prospective randomized controlled study to determine the effect of topical application of botulinum toxin A for crow's feet after treatment with ablative fractional CO2 laser.
abstract: BACKGROUND
  Botulinum toxin Type A (BoNT A) for the treatment of facial wrinkles is delivered through local injection. We previously demonstrated that topical surface application of BoNT A has negligible cutaneous bioavailability and is not effective in treating wrinkles.
  
  
  OBJECTIVE
  To determine the effect of BoNT A solution applied topically on the skin surface immediately after ablative fractional CO2 laser treatment.
  
  
  METHODS
  We conducted a randomized controlled trial for patients with periorbital wrinkles (crow's feet) (n = 10). Treatment was performed on both sides of the face with fractional ablative CO2 laser followed by the application of topical solutions of BoNT A on one side and normal saline as control on the other side. Pretreatment assessment was performed, and at 1 and 4 weeks after treatment.
  
  
  RESULTS
  There was a clinically significant greater degree of improvement in wrinkles after treatment with CO2 laser, on the topically applied BoNT A side. Also, the difference between the 2 treatment types (laser followed by topical BoNT A vs laser followed by saline) at 1 week and at 1 month was statistically significant.
  
  
  CONCLUSIONS
  Topically, noninjectable form of BoNT A applied on the surface of the skin after ablative fractional CO2 laser is effective in the treatment of lateral periorbital wrinkles.
authors.affiliation: *All the authors are affiliated with the Department of Dermatology, Henry Ford Hospital, Detroit, Michigan.
authors.forename: Bassel H
authors.initials: BH
authors.lastname: Mahmoud
authors.forename: Christopher
authors.initials: C
authors.lastname: Burnett
authors.forename: David
authors.initials: D
authors.lastname: Ozog
mesh_terms: D000279:Administration, Cutaneous; D000328:Adult; D000368:Aged; D019274:Botulinum Toxins, Type A / Q000008:administration & dosage* / Q000009:adverse effects; D003131:Combined Modality Therapy / Q000009:adverse effects; D004487:Edema / Q000209:etiology; D004890:Erythema / Q000209:etiology; D005123:Eye; D005148:Facial Dermatoses / Q000209:etiology; D005260:Female; D006801:Humans; D054020:Lasers, Gas / Q000009:adverse effects / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009465:Neuromuscular Agents / Q000008:administration & dosage* / Q000009:adverse effects; D010146:Pain / Q000209:etiology; D017060:Patient Satisfaction; D011446:Prospective Studies; D015595:Skin Aging
chemical_list: D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A