title: The Effect of Chemodenervation by Botulinum Neurotoxin on the Degradation of Hyaluronic Acid Fillers: An Experimental Study.
abstract: BACKGROUND
  Early degradation is a common complaint for hyaluronic acid fillers. Although the combination of hyaluronic acid fillers with botulinum neurotoxin type A presented improved clinical results, objective measurement of hyaluronic acid volumes has not been previously assessed.
  
  
  METHODS
  In this study, the authors have split the calvaria of the rabbit to mimic the glabellar region in humans. In this model, the authors applied hyaluronic acid alone to one side and hyaluronic acid combined with botulinum neurotoxin type A to the contralateral side. Two days and 3 months after the filler injection, magnetic resonance imaging was performed to assess the filler volumes.
  
  
  RESULTS
  Average initial volume of filler only and filler combined with botulinum neurotoxin type A was 0.61 cm on both sides, and there was no difference between initial volumes of the two sides (p = 0.735). At the end of 3 months, average degraded volumes of filler-only and filler combined with botulinum neurotoxin sides were 0.33 cm and 0.19 cm, respectively, and the degradation difference was significant between the two groups (p = 0.001). End volumes for the filler-only and filler combined with botulinum neurotoxin sides were 0.28 cm and 0.42 cm, respectively, and end volumes between two sides were also statistically significant (p < 0.001).
  
  
  CONCLUSIONS
  This study showed that hyaluronic acid filler application in combination with botulinum neurotoxin type A significantly decreases the degradation process and increases the remaining volume of the hyaluronic acid fillers at the end of the paralyzed period.
authors.affiliation: Samsun, Turkey From the Plastic Surgery and Radiology Departments, Ondokuz Mayis University Faculty of Medicine.
authors.forename: İsmail
authors.initials: İ
authors.lastname: Küçüker
authors.forename: Ibrahim Alper
authors.initials: IA
authors.lastname: Aksakal
authors.forename: Ahmet Veysel
authors.initials: AV
authors.lastname: Polat
authors.forename: Murat Sinan
authors.initials: MS
authors.lastname: Engin
authors.forename: Engin
authors.initials: E
authors.lastname: Yosma
authors.forename: Ahmet
authors.initials: A
authors.lastname: Demir
mesh_terms: D000818:Animals; D019274:Botulinum Toxins, Type A / Q000494:pharmacology*; D018890:Chemoprevention / Q000379:methods*; D003357:Cosmetic Techniques; D000067548:Dermal Fillers / Q000009:adverse effects / Q000494:pharmacology*; D004357:Drug Synergism; D006820:Hyaluronic Acid / Q000494:pharmacology*; D007271:Injections, Intradermal; D008297:Male; D023421:Models, Animal; D009498:Neurotoxins / Q000494:pharmacology; D011817:Rabbits; D011897:Random Allocation; D012060:Rejuvenation; D018709:Statistics, Nonparametric
chemical_list: D000067548:Dermal Fillers; D009498:Neurotoxins; D006820:Hyaluronic Acid; D019274:Botulinum Toxins, Type A