Botulinum Toxin for Aberrant Facial Nerve Regeneration: Double-Blind, Placebo-Controlled Trial Using Subjective Endpoints

Abstract

Aberrant facial nerve regeneration syndrome is systematically studied by constructing a subjective questionnaire organized into pertinent domains (impairment of quality of life, social interactions, perception of self-appearance, visual function, and perception of problem severity) and by physical assessment of degree of involuntary palpebral fissure closure during routine facial movements using videotaping and a physicians' grading scale. The videotape measurements of corneal light reflex to upper lid margin distance and vertical palpebral distance were made during adynamic and active facial expression. Thirty-six patients were studied (six in an open-label pilot study design and 30 in a multicenter, double-blind, placebo-controlled trial). Botulinum toxin type A injections consistently suppressed the degree of involuntary eyelid movement associated with smiling, chewing, and puckering by each measurement and in both study designs. In all subjective morbidity domains, improvement was demonstrated in the double-blind study design (quality of life, p < 0.05; social interaction, p < 0.001; personal appearance, p < 0.001; peripheral visual impairment, p < 0.01; and perception of severity, p < 0.05). Correlation between degrees of physical impairment was significant but low comparing degree of subjective impairment to direct videotaped measurements. Correlation was more significant comparing subjective scores to the physicians' grading scale assessment of degree of physical impairment. Impairment in quality of life, social interactions, and self-assessment of appearance closely reflected the nature of the morbidity associated with palpebral fissure asymmetry associated with aberrant facial nerve regeneration. The physicians' grading scale best reflected subjective morbidity over direct videotaped measurements.