Contralateral Depressor Labii Inferioris Chemodenervation for Congenital Unilateral Lower Lip Palsy

Abstract

Introduction: Congenital unilateral lower lip palsy - also known as asymmetric crying facies - is isolated asymmetry of the lower lip unilaterally. It is characterized by isolated lower lip asymmetry during smiling and speech. Although etiology is unknown, depressor labii inferioris (DLI) weakness is hold responsible. Aim: Purpose of this study was to evaluate the effectiveness of contralateral depressor labii inferioris botulinum toxin injection on patients' concern levels and patient satisfaction. Ten units of botulinum toxin A injection was carried out to the healthy contralateral side. Methodology: Eleven patients were treated. Patients' pretreatment and posttreatment concern regarding asymmetry during speech and smiling was evaluated with a questionnaire. Patients' perception of treatment satisfaction was also evaluated with a questionnaire. Results: Mean score related to concern about asymmetric appearance during smiling decreased from 1.6 +/- 0.8 to 0.5 +/- 0.5. Mean score related to concern about asymmetric appearance during speech decreased from 1.6 +/- 0.5 to 0.4 +/- 0.5. Eleven out of 11 patients reported improvement with speech whereas 10 out of 11 patients reported improvement with smiling. No weakness about oral competence was reported. Conclusion: Most congenital unilateral lower lip palsy patients are concerned regarding their asymmetric appearance while smiling or speaking. Chemodenervation of the contralateral DLI muscle reduces concern levels and has high patient satisfaction. Chemodenervation of the contralateral healthy DLI muscle is a valid, practical treatment option.