The role of botulinum toxin a in the establishment of symmetry in pediatric paralysis of the lower lip. 
Botulinum toxin A has been described as an effective adjunct treatment for achieving symmetry in adults with facial paralysis.  Few investigators have described the use of botulinum toxin A in pediatric patients with facial paralysis.  To present our preliminary experience with botulinum toxin A in pediatric patients presenting with asymmetry of the lower lip.  We performed a retrospective medical record review of all pediatric patients (age range, 4-17 years; mean [SD] age, 11.2 [4.7] years) with facial paralysis who were treated with botulinum toxin A injections from January 1, 2004, through December 31, 2012.  Patients presented for treatment at The Hospital for Sick Children, Toronto, Ontario, Canada, or the Massachusetts Eye and Ear Infirmary, Boston.  Using facial analysis software, we measured lower lip asymmetry in the patients' photographs before and after treatment, at rest, and in a dynamic state.  We performed analysis of variance to assess for improvement in symmetry.  We identified 18 patients with the following 3 primary indications for treatment: focal lip asymmetry (n = 11), extensive hemifacial asymmetry (n = 5), and focal synkinesis (n = 2).  We found no complications related to botulinum toxin A treatment.  The mean (SD) dynamic deviation before the injection was 3.5 (1.7) mm, whereas the mean dynamic deviation after the injection was 1.5 (0.8) mm.  The mean (SD) deviation correction was evaluated at 61% (6%) and was statistically significant (P = .04).  Botulinum toxin A injection is a safe procedure for improving localized asymmetry in pediatric patients with facial paralysis.  Preliminary results indicate that botulinum toxin A may be an effective treatment for lower lip asymmetry in children and adolescents.  4.