Ocular-oral synkinesis caused by partial injury of the zygomatic and buccal branches of the facial nerve after mid-face trauma

Abstract

BackgroundFacial nerve paralysis induced by acute traumatic facial nerve injuries limited to the zygomatic and buccal branches shows unique complication symptoms, such as strong co-contractions of the lower facial muscles around the lips during voluntary eye blinking (ocular-oral synkinesis). We investigated the characteristics of facial complications after facial nerve injury in the mid-face area and report the treatment results. MethodsA total of 21 patients with facial nerve injuries on the zygomatic and/or buccal branches were evaluated for the degree of facial synkinesis and mouth asymmetry. The patients with mild to moderate symptoms were treated with physical rehabilitation therapy combined with botulinum toxin (Botox) injection, and the patients with severe or uncontrolled symptoms were treated with surgical therapy. ResultsInitial/final mean synkinesis scores and mouth asymmetry degrees were 2.17/1.75 and 0.85/0.66 in the physical therapy group, and 3.11/0.78 and 2.41/-0.31 in the surgery group. Physical therapy with Botox injection alone did not result in significant improvements in synkinetic symptoms of the patients with mild to moderate synkinesis (p>0.05), whereas surgical therapy resulted in significant improvements in both synkinesis and mouth asymmetry (p<0.05). ConclusionsSurgical treatment is an effective adjustment procedure for management of facial complications of severe or uncontrolled synkinesis after facial nerve injury in the mid-face area.