Unveiling Novel Surgical Treatments for Facial Synkinesis: Myectomy of the Posterior Belly of Digastric and Stylohyoid Muscle

Facial synkinesis manifests as involuntary muscle movements alongside volitional facial actions and is typically managed with a combination of neuromuscular retraining, botulinum toxin injections, and in some cases, selective neurectomy. Some patients with synkinesis describe persistent neck tightness or pain at the level of the mandibular angle and horizontally towards the midline, similar to the anatomic course of the posterior belly of digastric (PBD) and stylohyoid muscles. There are limited studies exploring the involvement of the PBD and stylohyoid muscles in facial synkinesis and the use of chemodenervation as treatment. Herein, we present 2 patients with facial synkinesis and ipsilateral neck tightness and pain who underwent novel surgical treatment in the form of the standard selective neurectomy procedure along with a myectomy of the PBD and stylohyoid muscles. Following completion of the standard steps of selective neurectomy, the PBD and stylohyoid muscles were carefully dissected and separated from the surrounding structures. Both muscles were divided using bipolar electrocautery. Both patients reported improvement of neck pain and tightness immediately after the intervention and at the 6.5-month follow-up visit. These preliminary results show promise in aiding a subset of patients with synkinesis-related neck pain and tightness.