Effect of 3 Commercially Available Botulinum Toxin Neuromodulators on Facial Synkinesis: A Randomized Clinical Trial.

[IMPORTANCE] Botulinum toxin neuromodulators are an important treatment for facial synkinesis. Whether a difference in efficacy exists among the 3 different botulinum neuromodulators used in treating this condition remains unknown.

[OBJECTIVE] To evaluate the effectiveness of 3 commercially available botulinum toxin neuromodulators in the treatment of facial synkinesis.

[DESIGN, SETTING, AND PARTICIPANTS] In this single-blind, 3-arm comparison randomized clinical trial, 28 patients at the Facial Nerve Center, University of Utah, Salt Lake City, were randomized to onabotulinumtoxinA, abobotulinumtoxinA, or incobotulinumtoxinA treatment. Each patient was given the Synkinesis Assessment Questionnaire (SAQ) to assess severity of synkinesis before treatment and 1, 2, and 4 weeks after treatment, and improvements were compared among the groups. Data were collected from July 3, 2012, to March 31, 2015.

[INTERVENTIONS] Botulinum toxin type A neuromodulator (onabotulinumtoxinA, abobotulinumtoxinA, or incobotulinumtoxinA) injected into synkinetic areas of the face.

[MAIN OUTCOMES AND MEASURES] Synkinesis assessed using the SAQ (score range, 20-100; lower scores indicate less severe synkinesis) before treatment and 1, 2, and 4 weeks after treatment.

[RESULTS] A total of 28 patients (mean [SD] age, 49.1 [18.5] years; 8 [28.6%] male and 20 [71.4%] female), with 6 patients enrolled multiple times, received 38 treatments (15 onabotulinumtoxinA, 13 abobotulinumtoxinA, and 10 incobotulinumtoxinA). No significant difference existed in baseline pretreatment SAQ scores among the 3 groups. Mean (SD) SAQ score improvement at 4 weeks was 41% (31%) for the onabotulinumtoxinA, 42% (20%) for the abobotulinumtoxinA, and 17% (18%) for the incobotulinumtoxinA groups. No significant differences were noted in SAQ score improvements among the 3 groups at weeks 1 and 2 after treatment (week 1 mean improvements of 42% in the onabotulinumtoxinA, 45% in the abobotulinumtoxinA, and 26% in the incobotulinumtoxinA groups; P = .19; week 2 mean improvements of 43% in the onabotulinumtoxinA, 46% in the abobotulinumtoxinA, and 28% in the incobotulinumtoxinA groups; P = .20). The difference in mean SAQ score improvement for abobotulinumtoxinA vs incobotulinumtoxinA from pretreatment to 4 weeks after treatment was not significant (30 vs 12 points; P = .11) despite a significant difference in mean total SAQ score for abobotulinumtoxinA vs incobotulinumtoxinA (40.34 vs 58.00; P = .02).

[CONCLUSIONS AND RELEVANCE] AbobotulinumtoxinA had similar efficacy to onabotulinumtoxinA and incobotulinumtoxinA for the management of facial synkinesis up to 4 weeks after treatment. IncobotulinumtoxinA had significantly less effect on SAQ score improvement than onabotulinumtoxinA at 4 weeks, perhaps because of the shorter duration of action. Shorter intervals between treatments or larger doses may be required when using incobotulinumtoxinA treatment for facial synkinesis.

[TRIAL REGISTRATION] clinicaltrials.gov Identifier: NCT03048383.

[LEVEL OF EVIDENCE] 1.