Hemifacial spasm (HFS) is a paroxysmal involuntary jerking of the hemifacial muscles, usually confined to one side of the face, hence the name hemifacial spasm, occasionally seen in both sides. Most patients with primary facial spasm develop it after middle age, more often in women. The twitching of the corners of the mouth is the most noticeable, and in severe cases, it may even involve the ipsilateral broad neck muscles, but the frontal muscles are less frequently involved. The spasticity intensity is graded according to Cohen et al. Grade 0: no spasm; Grade 1: increased transients or mild tremors of facial muscles caused by external stimuli; Grade 2: spontaneous mild tremors of eyelids and facial muscles without dysfunction; Grade 3: pronounced spasm with mild dysfunction; Grade 4: severe spasm and dysfunction, e.g., the patient is unable to read a book and has difficulty walking alone because of inability to keep the eyes open. Neurological examination is not positive for signs other than paroxysmal twitching of facial muscles. A small number of patients may have mild paralysis of the affected facial muscles in the late stage of the disease. How to diagnose facial muscle spasm? The diagnosis can be made accurately according to the typical clinical manifestations, but it needs to be differentiated from the following diseases. 1, facial muscle twitching after facial palsy: there is a clear history of facial palsy in the past, due to incomplete recovery of facial palsy caused by axonal regeneration disorder, the affected side mostly remains with varying degrees of facial muscle weakness and paralysis, which is one of the differential diagnosis of facial muscle spasm. 2. Idiopathic blepharospasm: it is a bilateral blepharospasm, often accompanied by mental disorders, and electromyography shows asynchronous discharges of the facial muscles with normal frequency, probably due to dysfunction of the cone system 3. Habitual facial muscle spasm: it is common in children and young adults, and is a transient forced facial muscle movement, often bilateral. The EMG and EEG of hysterical blepharospasm and habitual facial muscle twitches are normal, and the muscle contraction waves appearing on the EMG during the twitches are the same as those produced during active movements. 4, secondary facial muscle spasm: cerebellar bridge angle tumor or inflammation, brain bridge tumor, brainstem encephalitis, medullary cavitation, motor neuron disease, cranial injury can appear facial muscle twitching, but often accompanied by other brain nerve or vertebral bundle damage, such as ipsilateral facial pain and facial sensory loss, hearing impairment, contralateral or limb muscle strength loss, etc., and facial muscle twitching is only one of the symptoms, so it is not difficult to distinguish. 5, epilepsy: facial muscle limited twitching may also be partial motor epilepsy, but its twitching amplitude is larger, and often involves the neck, upper limbs or even the lateral limbs, or the typical Jackson seizures that spread in the order of cortical motor areas. Epileptic waves are seen on the EEG. Epilepsy that is limited to only facial muscle twitching is rare. What are the treatment measures for facial muscle spasm? 1.Medication Except for phenytoin sodium or carbamazepine, which may be effective in some mild patients, general central sedatives, depressants and hormones have no significant efficacy. 2.Surgical treatment Microvascular decompression Jannetta advocated in 1966, is now a common method of international neurosurgery. It is done by separating the responsible blood vessels compressing the facial nerve under the microscope and padding them with polyester cotton, so that the blood vessels no longer touch the nerve and achieve the purpose of treatment. This procedure does not damage the facial nerve and can provide relief of symptoms in 95-98% of patients with a very low recurrence rate, making it the best treatment for facial spasm.