Prevention and Treatment of Post-Paralytic Synkinesis: Critical Changes Following Severe Facial Palsy

Abstract

Facial synkinesis following severe facial palsy has been observed clinically across a wide range of patient groups, from infants to older adults, indicating that it is not limited to any specific demographic. In one of the largest studies on the natural progression of idiopathic peripheral facial nerve palsy, synkinesis was reported in approximately 16% to 55% of patients. The severity of facial synkinesis generally correlates with the severity of the initial facial palsy. Various types of nerve injuries have been categorized based on the extent of damage to the endoneurium, perineurium, and axons. Aberrant responses and ephaptic transmission following facial nerve injury are responsible for the clinical manifestations of facial synkinesis. It is crucial to minimize facial synkinesis in the early stages and to ablate it in the chronic stages to effectively manage this challenging complication following severe facial palsy. We advocate for physical therapy, including neuromuscular retraining during the acute phase, as a viable option for patients at high risk of developing facial synkinesis after a severe episode of Bell’s palsy. This approach helps prevent excessive movement (hyperkinesis) and enables patients to recognize and manage unwanted co-contractions (synkinesis). Several treatments targeting the facial nerve and muscles are available, including chemo-denervation, selective myectomy, and selective neurectomy. These interventions aim to address aberrant regeneration and peripheral ephaptic transmission.