Quantitative ultrasonography of facial muscles in patients with chronic facial palsy

In this study we introduce quantitative facial muscle ultrasound as a diagnostic tool for patients with chronic unilateral facial palsy.Muscle area, thickness, and echo intensity of 6 facial muscles (frontalis, orbicularis oculi, orbicularis oris, depressor anguli oris, depressor labii inferioris, and mentalis) and of 2 chewing muscles (temporalis and masseter, as controls) were measured in 20 patients with chronic facial palsy.Aside from 1, all facial muscles were significantly smaller on the paralyzed side. With exception of frontalis and orbicularis oculi muscles, all other facial muscles showed significantly higher echo intensity on the affected side. Muscle size and echo intensity of the chewing muscles showed no side-to-side asymmetry.Quantitative ultrasound of facial muscles helps to better characterize their status in patients with chronic facial palsy in the phase of denervation and during regeneration.