Evaluation & Treatment
Synkinesis means “simultaneous movement.” Synkinesis occurs secondary to abnormal facial nerve regeneration after Bell’s palsy, or in instances where the facial nerve has been cut and sewn back together. The facial nerve fibers can implant into the different muscles in cases of Bell’s palsy. Additionally, when the nerve is re-sewn, the facial nerve fibers oftentimes reconnect to the wrong nerve group, causing undesired and simultaneous facial movement. Synkinesis, therefore, results in abnormal synchronization of facial movement where muscles, other than those intended, contract together during a particular movement pattern.
Synkinesis does have some predictable facial muscle patterns and can have a range of severities. It is important to separate true paralysis and synkinesis. If patients have good facial tone and some visible movement, then they do not have full paralysis and many of their abnormal facial movements are a result of synkinesis. The most common effect of synkinesis is when patients experience eye closure during a smile. The eyes tend to twitch or close while the patient is trying to smile or laugh. Synkinesis can also be a powerful cause of inability of the corner of the mouth to move upwards in patients who have regained their facial tone. Patients usually just think that their face is not moving; however, in many patients their inability to smile is secondary to synkinetic (simultaneous) movement of muscles that droop the corner of mouth (depressor anguli oris, platysma, and mentalis muscles) and muscles that elevate the area (zygomaticus major and minor). Other patterns of synkinesis are dimpling in the chin and narrowing of the eyes. In addition to these abnormal movement patterns, synkinesis also causes increased muscle tone with spasm, contracture and tightness of the neck bands and cheeks.
There are some ways to reduce the risk of developing synkinesis after Bell’s palsy. The Chevalier’s method is one of the more common ways of using a “facial re-education” method to prevent synkinesis and educate your facial muscles. Patients are encouraged to maintain facial symmetry by keeping the normal side of their face up when speaking, chew food with eyes open, avoid gum, wear sunglasses to prevent squinting, massage the intraoral buccal area, always align the face to block associated movement, Stretch orbicularis oculi (eye muscles). Patients are also encouraged to really work on having slow and symmetric movements. The key aspect of prevention is the first 3-4 months after injury or Bell’s palsy. It is important to note that some studies have shown that electrical stimulation can result in increased likelihood of developing synkinesis.
Once synkinesis has occurred, treatment relies on three distinct modalities: neuromuscular retraining (physical therapy), Botox (botulinum toxin) and surgery. Treatment of synkinesis can be initiated at any time after its occurrence. This may be even years after a patient has suffered Bell’s palsy or facial paralysis.
Neuromuscular retraining and physical therapy for synkinesis is very different than what is performed for other medical problems. Facial neuromuscular retraining is more comparable to a vocal therapist that is treating a singer who has hoarseness or poor mechanics. Facial neuromuscular retraining is primarily focused on coordinating appropriate facial muscle movements. This is achieved by inhibiting the activity of the abnormal movement patterns, resulting in “auto-paralysis” of unwanted muscles.
The muscles that are contracting abnormally are first identified. Muscles that are contracting out of sequence are inhibited. Small steps are usually taken in order to gradually retrain the muscles, as there needs to be significant changes at the neurologic (brain) level for success. Electrical stimulation is avoided as it tends to increase the overactive muscles. Muscles that are extremely overactive in the cheek and neck are actively massaged and stretched. Patients are discouraged from undergoing strong muscle strengthening exercises, as again this is more about re-coordination rather than stimulation. Patients are also taught how to elevate the upper eyelids during eating to reduce the eye synkinesis. Ninety percent of the therapy exercise can be done by the patient at home. Other treatment modalities will focus on mirror and video exercises.
The second mode of therapy for synkinesis is Botox (botulinum toxin-A). Botox is used in conjunction with facial neuromuscular therapy in most cases. Botox works by reducing the activity of the muscles that are overactive or uncoordinated. Most common areas of injection are eye muscles (orbicularis), neck bands (platysma), and chin dimpling (mentalis). Botox can also be used to symmetrize the face by reducing the activity of certain muscles on the normal side of the face such as: forehead, lower lip depressors (depressor anguli oris) and crow’s feet (orbicularis).
The final modality for treating synkinesis is surgery. Surgery is utilized only when physical therapy and Botox have been unsuccessful in obtaining the desired results. Selective neurolysis is the latest advancement in the treatment of synkinesis. During this surgery, the surgeon releases the platysma muscle and decreases the activity of the nerves that pull the mouth downward to allow for the mouth corners to once again turn upward. The procedure is complex, but the recovery period is similar to that of a facelift. Static suspension of the corners of the mouth, blepharoplasty (eyelid surgery), and facelift are also commonly utilized to address synkinesis.