Spastic squint is a general term for the twisting and turning of the head and neck caused by involuntary contraction of the neck muscles. According to Nutt et al, the prevalence of spastic squint is about 9 per 100,000. In the United States, there is an association of about 90,000 people with spastic levator neck. The number of patients in China is estimated to be several times higher than that in the United States.
Diagnosis of Spastic Squint
Diagnosis of spastic squint is easy. It is basically confirmed when you see a patient with a tilted head and neck with incessant shaking or trembling, but the following two points must be met to confirm the diagnosis.
1.The patient has dystonia.
2, exclude other diseases. For example, hepatomegaly, Parkinson’s disease, cerebral palsy sequelae, myotonic squint, etc.
Clinical manifestations of spastic squint
Most of the cases are adult onset, but a few cases occur in children. I have encountered two cases in 6-year-old children, one case in a 12-year-old student, and the largest case in an 86-year-old patient. It can occur in both sexes, with a slightly higher incidence in females than in males. It occurs after certain triggers (e.g., stress, exertion, anger, etc.) and gradually worsens, rarely subsiding or receding on its own. The head is often involved bilaterally, but the degree of involvement is often asymmetrical resulting in a twisting motion of the head to one side. The condition worsens with activity or work stress and decreases or disappears during sleep. Symptoms often appear suddenly, as a pull on the neck, or as an involuntary rotation of the head. Abnormalities in head and neck posture can manifest in a variety of postures, which can be rotational, lateral, anterior, and posterior extension, followed by head pull, posterior cervical tilt, and anterior cervical tilt, with a few patients presenting with simple deviation.
Clinical typing of spastic squint
1.Horizontal rotation type. Spastic squinting neck in which the patient’s head is turned to one side with spasm of sternocleidomastoid muscle on one side and cephalic grip muscle on the other side.
2.Lateral flexion type. Spasm of the same side of the neck muscles, such as the sternocleidomastoid, cephaloclavicularis, scapularis, vastus cervicis, anterior, middle and posterior oblique muscles on the same side, when some of these muscles spasm, the patient’s head and neck to the side of the flexion of the spastic squint.
3.Rotational posterior tilt type. When one side of the head pinch muscle, trapezius muscle and scapular muscle spasm, the patient’s head and neck both turn to the affected side and tilt backwards.
4.Rotational anterior tilt type. When the spasm of sternocleidomastoid muscle and broad cervical muscle is mainly on one side, the patient’s head rotates to the affected side and tilts forward.
5.Over-extension type. The spasmodic squinting neck in which the patient’s head and neck are overextended backward and the eyes are looking at the sky is caused by the spasm of the trapezius, cephalic muscle and semispinal muscle on both sides at the same time or the spasm of one or two pairs of muscles.
6.Overflexion type. When the sternocleidomastoid, cervicalis brevis and oblique muscles (anterior, middle and posterior) on both sides spasm at the same time or one or two pairs of them, the patient’s head and neck are flexed forward.
7.Mixed type. The patient’s head and neck are tilted in a variable state, and the spastic squint is accompanied by muscle spasm in other parts.
8. Painful type. Spastic squib with one of the above-mentioned types of performance, accompanied by nerve compression caused by spasm in the neck, shoulder, back and other parts, causing pain.
The clinical typing of spastic squints gives the basis for the implementation of antispasmodic surgery.
Drug treatment, botulinum toxin injection treatment, surgical treatment
1. For light patients in the early stage of the disease, medication can be used. Patients with insomnia and anxiety symptoms can be treated with clonidine; for patients with depression, they can be treated with Prozac, and other drugs include haloperidol. Generally speaking, the effect of drug treatment is limited.
2, for patients with poor results of oral and abdominal drug treatment, you can generally choose Botox injection treatment. The dosage of each affected muscle is not more than 100 units per injection, and the total amount of each injection generally does not exceed 380 units. The effect of botulinum toxin injection for spastic diastasis can only be maintained for about three months, and cannot achieve the effect of radical cure.
Botox injections are ineffective in 5% of patients.
For patients with severe spastic squint that seriously affects their life and work, surgery can be chosen. There are various surgical methods to treat spastic squint, including muscle amputation, neuro-microvascular decompression, selective neurectomy, and thalamic nucleus stimulation or destruction. Regardless of which surgery is performed, the key is to accurately identify the muscle group that is spastic in the neck and choose a reliable method to relieve the muscle spasm.
Current common surgical methods.
1.Muscle amputation: It is to cut off the abnormal spastic muscles in the neck to relieve spastic squint, this surgery is simple, but its effect is not satisfactory, with the scar adhesions of the cut muscles, the spastic symptoms will be aggravated again, and there are many muscles in the neck, it is difficult to identify the middle and deep spastic muscles, and it is difficult to cut them off, after cutting off multiple groups of muscles in the neck, the scar will seriously affect the beauty of the neck.
2, thalamic nuclei stimulation or destruction: It is the use of stereotactic technology to place electrical stimulators into the nuclei in the thalamus or pallidum for electrical stimulation or destruction of these nuclei to achieve the purpose of treatment. From the current literature, this method is not effective in unilateral stimulation or destruction of the thalamic nuclei, but requires bilateral stimulation or destruction, with an efficiency of 40-60% and a recurrence rate of about 19%. For this reason, this surgical method is considered when other treatments are ineffective.
3, paraneoplastic microvascular decompression + cervical nerve root cut: the purpose is to release the posterior inferior cerebellar artery and vertebral artery compression of the paraneoplastic nerve, relieve the spasm of the muscle innervated sternocleidomastoid and trapezius muscle, cut the anterior root motor branch of cervical 1-3, release the spasm of the middle and deep cephalocervical semispinal muscle and small muscle group behind the head, after years of clinical observation, the efficiency is more than 90%. However, this method requires precise determination of the involved muscles of spastic trapezius. For relieving the neck muscles involved in cervical 4-8 innervation, the method of cutting the anterior root cannot be taken, otherwise it will produce dysphagia and shoulder and upper limb mobility disorders and respiratory muscle weakness in patients.
4, selective spinal nerve dorsal branch severance: in the distal side of the spinal ganglion, the ventral root and dorsal root unite to form the spinal nerve, penetrate through the intervertebral foramen, send out a spinal membrane back to the branch, immediately divided into ventral branch and dorsal branch, at 1-2 cervical nerve outside, the dorsal branch of each cervical nerve are backward through the medial bend of the cervical transverse process muscle around the articular eminence joint, into the cephalic semispinal muscle and cervical semispinal muscle interval, and constitute the cervical plexus and The ventral branch of the cervical spinal nerve, which forms the cervical and brachial plexus, passes between the anterior cervical intertransverse muscle and the posterior cervical intertransverse muscle. This selective dorsal branch of the cervical spinal nerve can avoid damage to the cervical plexus, brachial plexus and nerves innervating the pharyngeal muscles, and achieve good surgical results in muscles with cervical 4-8 innervation involvement, overcoming the limitations and shortcomings of the cervical 1-3 anterior root motor branch surgery, while having the advantages of no risk of opening the conus plate to access the spinal cord for surgery, unaffected stability of the cervical spine, and less surgical trauma. Over the years, we have achieved good results in patients with spastic squint by meticulously identifying the muscle groups of cervical spasm and treating them with the latter two methods, and 92% of patients have recovered satisfactorily with long-term follow-up observation.