1.What is spastic squint: Spastic squint is a paroxysmal involuntary contraction of the neck muscles caused by abnormal impulses of the central nervous system, causing the head and neck to twist to one side or tilt spastically. 2.Etiology of spastic squint: Most of the causes of spastic squint are caused by lesions of nerve cells deep in the brain. These patients can have a history of encephalitis, birth asphyxia, jaundice, etc. These will show some abnormalities on CT or MRI. There are also some patients who do not have any changes on imaging. A few patients can be caused by hysterical attacks or local irritation around (cervical spine injury or inflammation). 3. Clinical manifestations of spastic squint: The various abnormal postures of spastic squint are caused by the abnormal contraction of the muscles in the corresponding parts of the neck. The contraction of sternocleidomastoid muscle, trapezius muscle and cephalicus muscle is the most likely to show symptoms. When one sternocleidomastoid muscle contracts, the head rotates to the opposite side; when both sternocleidomastoids contract simultaneously, the head flexes forward; when both cephalicus and trapezius muscles contract simultaneously, the head overextends posteriorly. When the spasm is severe, the affected muscles can become hypertrophic. (1) Rotation type: The head is spasmodically rotated to one side along the longitudinal axis of the body. (2) Posterior tilt type: The head is tilted backward towards the back, facing the sky. (3) Forward flexion type: The head is flexed forward and the lower jaw is placed against the chest. (4) Lateral flexion type: The head deviates from the longitudinal axis to the left or right, with the ear close to the shoulder, often accompanied by ipsilateral shrugging of the shoulder. 5. Internal treatment of spastic squint: Clonidine can improve the symptoms of spastic squint to some extent. Intramuscular injection of botulinum toxin type A is effective in most patients. Because the postural abnormalities of spastic squint are usually complex, often involving rotation, tilt, supination and shrugging, and rarely due to the contraction of a single muscle, it is important to identify the main muscles involved in the postural abnormalities before administering botulinum toxin intramuscularly. These muscles are often hypertrophic and have pressure pain, sometimes it is necessary to make electromyography to make a correct judgment. 6, the efficacy and side effects of botulinum toxin injection Several studies have shown that 60% to 92% of patients with abnormal head posture improved after botulinum toxin injection. The average time from injection to effect is 1 week, and the average improvement period is 3 months. In order to avoid the formation of antibodies that could lead to drug failure, injections are usually repeated until 4-6 months. The most common side effect is dysphagia, which usually occurs at 5 days after the injection. Most symptoms are mild and last for about two weeks before resolving. About 25% of patients experience neck weakness and a feeling of heaviness in the head when sitting. This phenomenon is transient and can be avoided by reducing the total dose of Botox injections. 7.Surgical treatment of spastic squint Surgical treatment is still in the development stage, and there is not a unified standard procedure. The following surgical methods are commonly used: (1) Dandy surgery: bilateral anterior root amputation of 1, 2, 3 or 4 branches of cervical nerve plus bilateral paraneoplastic nerve root amputation. The surgery is complex and requires occipital craniotomy and opening of 1-4 vertebral plates in the neck. (2) Selective cervical muscle resection and paraneoplastic neurectomy: According to the different types of spastic squint and abnormal posture of the head, the relevant muscles and paraneoplastic nerves are selectively resected. This procedure is the most effective method at present. (3) Stereotactic brain destruction: Stereotactic surgery to destroy certain nuclei to treat spastic strabismus has not yet obtained a positive conclusion. Stereotactic disruption is suitable for patients with severe disease and spasticity involving a wide range of muscles. The surgical target can be chosen from the medial pallidum and the ventral lateral nucleus of the thalamus.