Facial Nerve Compression and Paralysis

Clinical Presentation and Diagnosis

• The primary sign of facial nerve compression by a large pleomorphic adenoma of the parotid gland is impaired facial nerve movement, which manifests as facial weakness or paralysis on the affected side, according to the American College of Surgeons 1
• Peripheral facial paralysis affects the entire hemiface, including the forehead, whereas in central paralysis, the forehead is preserved due to bilateral innervation of the frontal musculature, as noted by the American College of Radiology 2
• The House-Brackmann scale can be used to quantify the degree of facial dysfunction, and electroneurography (ENoG) and electromyography (EMG) can evaluate the degree of axonal degeneration and muscular activity in peripheral facial paralysis, respectively 2

Imaging and Tumor Evaluation

• MRI provides superior visualization of both intracranial and extracranial portions of the facial nerve and can better distinguish tumors from surrounding tissues due to superior soft tissue contrast resolution, as recommended by the American College of Radiology 3, 2
• High-resolution CT scan of the temporal bone without IV contrast is the first-line imaging modality for suspected petrous temporal bone fractures, as recommended by the American College of Radiology 4, 5
• The following table summarizes the imaging and radiology for facial paralysis:

Surgical Planning and Management

• Facial nerve preservation should be performed when preoperative function is intact and a dissection plane can be created between the tumor and nerve, according to the American College of Surgeons 1
• Resection of involved facial nerve branches is recommended when facial nerve movement is impaired preoperatively or branches are found to be encased or grossly involved by confirmed malignancy, as suggested by the American College of Surgeons 1
• Patients with preoperative facial weakness and/or evidence of perineural invasion have been shown to have a worse prognosis, as reported by the American College of Surgeons 1

Medical Management

• Anticonvulsant medications, particularly carbamazepine, may help control facial twitching symptoms, as suggested by the American Academy of Neurology 6
• Oral corticosteroids within 72 hours of symptom onset are recommended for peripheral facial paralysis, such as Bell's palsy, and considering antiviral therapy in selected cases, as suggested by the American Academy of Otolaryngology-Head and Neck Surgery 7
• Current evidence strongly supports a conservative approach, avoiding routine imaging studies in typical cases of Bell's palsy, and prioritizing early treatment with corticosteroids to optimize clinical outcomes and patient quality of life, as recommended by the American Academy of Otolaryngology-Head and Neck Surgery and the American College of Radiology 7, 2, 8, 9

Emergency Response and Poison Control

• Contact emergency services immediately if the patient exhibits sleepiness, seizures, difficulty breathing, or vomiting after exposure, as recommended by the American Heart Association 10
• Symptoms of botulism, including descending paralysis and fixed pupils, require immediate emergency response, as advised by the Centers for Disease Control and Prevention 11
• For chemical exposures, the American Heart Association recommends brushing off powdered chemicals with a gloved hand, removing contaminated clothing, and irrigating eyes immediately with copious amounts of water 10
• Avoid administering milk or water for ingested poisons unless specifically advised by poison control, and do not administer activated charcoal or syrup of ipecac without poison control guidance, as recommended by the American Association of Poison Control Centers and the American Heart Association 10