Facial Paralysis: Causes, Symptoms, Treatments, and the role of Neuromonitoring in the Prevention and Diagnosis.
By Cesia M. Alvarez and Faisal R. Jahangiri A few months ago, the famous singer, Justin Bieber, alerted his fans that …
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Oct 12, 2022
A few months ago, the famous singer, Justin Bieber, alerted his fans that he had facial paralysis that later was known to be caused by Ramsay Hunt Syndrome. This syndrome starts to emerge when the virus that causes chickenpox directly infects the person’s facial nerve, thus resulting in a type of facial paralysis. Although this neurological disorder could seem like a rare condition, the reality is that any individual, under the right circumstances, could suffer from it.
Paralysis is the inability to perform muscle movements voluntarily. Different types of paralysis affect or target other areas of the body. Today we are going to discuss facial paralysis – its causes, its symptoms, and its treatments. But first, what is facial paralysis? Facial paralysis refers to the inability to move the muscles of the face. In other words, a patient suffering from this condition will be unable to move, for example - one or both of their cheeks, forehead, eyelids, and/or mouth. As a result, this neurological problem becomes a tremendous burden for the patient by affecting their ability to speak, eat, blink, etc.
Facial paralysis can develop through different routes. For instance - direct trauma to the area (i.e., iatrogenic cause), suffering a stroke, other diseases such as diabetes, brain tumors, congenital defects, and inflammation or weakness of the facial nerve (Bell’s palsy). This latter, Bell’s palsy, is the most common type of facial paralysis. According to The National Institute of Neurological Disorders and Stroke, more than 40,000 Americans yearly suffer from Bell’s palsy. Some of the symptoms that start to emerge right before facial paralysis appears are, for example - facial pain, dropping of eyelids and mouth, drooling, headaches, abnormal facial movements, loss of taste, extreme sensitivity to loud noises, etc.
When treated immediately, patients who have facial paralysis have better and more substantial chances to recover successfully and return to their regular muscular facial activity. However, each person has different recovery times that rely on factors such as the extent of the paralysis (full or partial). Some of the most common treatments that are being used for the recovery of this neurological pathology can range from surgical interventions such as decompression of the injured nerve or nerve transfers that aim to recover the loss of function by transferring nerve branches from other local healthy nerves to less risky treatments such as oral steroid medications, analgesics, viral medications, etc. Moreover, according to The Facial Paralysis Institute – even though facial nerve decompression surgery is a commonly used treatment for facial paralysis, it comes with several risks such as hearing loss, dizziness, etc. However, it is through these surgical treatments that intraoperative neurophysiological monitoring (IONM) plays a fundamental role in safely guiding the surgeon during the procedure and minimizing any post-operative neurological deficits.
Intraoperative neuromonitoring (IONM) has become a critical service in preventing and minimizing facial paralysis during surgeries. Because of its location and extensive ramification, the facial nerve is prone to injuries during surgical procedures localized in that region, such as posterior fossa surgery, cerebellopontine angle (CPA) tumors, brainstem and parotid gland surgery, etc. Monitoring the facial muscles during these surgeries can minimize any postoperative neurological deficits. Electrical stimulation of the neural tissue during these types of surgical procedures can be used as a prognostic and prevention tool for this neurological disorder. Corticobulbar Motor Evoked Potentials (CoMEP) and Electromyogram (EMG) are intraoperative neuromonitoring tests commonly used to monitor cranial and peripheral nerve activity indirectly. For example, EMG records the electrical activity of the muscles being subjected to or at risk during surgical procedures. Sub-dermal needle electrodes are inserted into the facial muscles at risk for recording spontaneous EMG (s-EMG), triggered EMG (t-EMG), and CoMEP responses. Thus, any changes in the t-EMG, CoMEP recordings or spontaneous activity in EMG signals are immediately evaluated by the IONM professional, and the surgeon is alerted in real-time. Therefore, the surgeon can take immediate corrective action and avoid damage to the facial nerve. Utilizing multimodality IONM during these surgeries can help better patient outcomes.
Faisal R. Jahangiri (2012). Surgical Neurophysiology – A reference guide to intraoperative neurophysiological monitoring (IONM), 2nd edition.