Platysma synkinesis in facial palsy and botulinum toxin type A.

Objectives/hypothesis: Facial synkinesis is a well-known disabling occurrence following severe facial palsy. Platysma muscle, innervated by the facial nerve, can be involved in synkinesis as well, but thus far has been little investigated. The aim of our study is to evaluate the presence of platysma synkinesis and its clinical evolution after onabotulinumtoxinA (BoNT-A) (Botox(®) ; Allergan Pharmaceuticals, Irvine, CA) injections.

Study Design: Retrospective study.

Methods: Sixty-nine patients were treated for synkinesis following facial palsy. Of those, 45 were affected by platysma synkinesis and thus were injected in the platysma muscle. The total number of sessions was 124. The Sunnybrook Facial Grading System (SFGS) and a specific platysmal evaluation for the presence and severity of synkinesis and local symptoms were performed before and after BoNT-A treatments.

Results: Platysma synkinesis was present in 65.2% of the sample and was associated with subjective complaints in 85.5% of the cases. The facial expressions more related to platysma synkinesis were snarl, followed by open-mouth smile and lip pucker. After each BoNT-A treatment, there was an improvement in facial symmetry at rest and during voluntary movements, a global reduction of synkinesis, and a specific reduction of synkinesis and symptoms related to the platysma. No adverse reaction to BoNT-A occurred.

Conclusion: Platysma involvement represents a recurring and symptomatic problem in patients affected by synkinetic recovery following facial palsy. After BoNT-A injections, there is a reduction in platysma synkinesis and related symptoms.

Level Of Evidence: 4.