The use of botulinum toxin for oral-ocular synkinesis in facial paralysis

Abstract

Oral-ocular synkinesis is a common, uncomfortable, and disfiguring sequela of facial nerve palsy. Despite widespread use of chemodenervation as a non-surgical intervention, limited literature exists on optimal dosage and administration techniques in these patients. This study aims to describe a reliable chemodenervation injection technique and report objective measurements and subjective satisfaction outcomes. Prospective pre-post interventional study where new, consecutive patients with previously untreated oral-ocular synkinesis secondary to facial nerve palsy were included. Patients completed a Synkinesis Assessment Questionnaire and standardized photographs were taken before and after botulinum toxin injections. Palpebral fissure symmetry was measured from photographs, with the unaffected side functioning as the control. Sixteen patients were included in the prospective study. Mean age was 48 years old and 56% male. Botulinum toxin was injected into the upper and lower medial preseptal, upper and lower lateral pretarsal, and lateral orbital orbicularis oculi (10-13 units). Standardized photographic comparison demonstrated significant improvement in palpebral fissure height with smile (p < 0.01) and lip pucker (p < 0.01). Relevant items on the Synkinesis Assessment Questionnaire also significantly improved (p < 0.01). This reliable botulinum toxin injection technique for oral-ocular synkinesis demonstrated significant improvement in subjective quality of life metrics and objective palpebral fissure height during both smile and pucker.