I. Concept of spasmodic torticollis
Spasmodic torticollis is an involuntary continuous or paroxysmal contraction of certain muscles in the neck, i.e. spasm or clonus, causing the patient’s head and neck to be in a forced abnormal posture or involuntary movement, which has different clinical manifestations depending on the participating muscles, causing the head and neck to rotate to the left or right, to bend to the left or right (also called lateral tilt or lateral bend), to bend forward (or extend forward), to tilt backward, or even to have a mixture of several postures and movements in an irregular state. This group of involuntary abnormal head and neck postures and movements is clinically referred to as spastic squint.
In the early literature and neurological and surgical monographs in China, the disorder was classified as torsional spasm, which was considered as a local manifestation of torsional spasm. After the 1950s, the neurological and surgical monographs classified the syndrome as an extra-pyramidal disease. It is considered to be an organic disease and a functional movement disorder of the extrapyramidal system.
Etiology and pathology
The etiology of the disorder is unknown, and there is no exact etiology and pathology reported in the literature so far. It is believed that the pathogenesis is due to pathological changes in some structures or functions of the extrapyramidal system, resulting in clinical symptoms. The lesion should be localized in the basal ganglia region or in structures related to the extrapyramidal system and their dysfunction. The pathological basis is similar to that of extrapyramidal disorders such as torsional spasm. Foreign experts have reported cases of spastic trapezius death due to other diseases in which autopsy revealed lacunar cerebral infarction.
To date, imaging such as CT and MR of the head has not been able to confirm the presence of intracranial focal signs in patients with spastic leptomeningeal neck. There are many types of clinical manifestations of spastic leptomeningeal neck, with great individual differences, and it is difficult to fully integrate and unify a particular pathological explanation with the complex clinical presentation. Some causative factors are of interest: pre-morbid stress, life and work stress, overexertion, mental stimulation, head trauma, and antipsychotic medication. Family history should also be noted.
Pathological changes of spastic muscles and involved nerves
There were 776 cases of spastic squint treated in our hospital, and pathological sections of the excised spastic muscles were made. It was found that: the muscles were obviously degenerated, the transverse lines disappeared, some of the nuclear chains were obvious, the muscles were congested, the fatty tissue was proliferated, and some of the muscle cells were swollen or atrophied. Among the resected nerves 454 pathological sections were reported: nerve degeneration, proliferation of fibrous and adipose tissue, and glassy nerves. These results are available for readers’ reference.
Clinical manifestations and diagnosis
I. Common clinical manifestations and types of spastic diagonal neck
(A) Common clinical manifestations
Most patients have a slow onset and a cryptogenic onset. At the beginning of the disease, they feel neck discomfort, soreness and swelling, head and neck obstinacy, involuntary deviation or jerking, and uncontrollable neck movement. In some cases, the symptoms are not obvious and there is no obvious discomfort, but bystanders notice the ectopic feeling of the head and neck. When the slanting neck is progressively aggravated, the head and neck are uncontrollably forced to deflect or twitch paradoxically. The muscle twitches are painful and locally hard, full and thickened. The head and neck deviation may be accompanied by abnormal activities in other areas, such as shoulder lifting, shoulder shrugging, upper limb inversion, etc. The symptoms are aggravated by emotional tension, excitement, work and life exertion. After resting, the symptoms are relieved and the spasticity disappears after sleeping. The symptoms may also be due to compensatory effects of spastic squint, strabismus, and changes in the physiological curvature of the spine. A few patients use cervical brace or cervicothoracic brace for a long time to correct the head and neck position. Some patients also use their hands to support the head and ears, cheeks or jaws to correct the head position for a long time. Some people can even correct the oblique neck by using fingers or objects to point pressure on a sensitive point on the cheek. Most patients are unable to correct the head position on their own.
Patients can sometimes provide a trigger for the onset of the disorder, and more patients have no cause to describe. The disorder is difficult to treat effectively. The majority of patients have been treated with medication since the onset of the disease, some of whom have shown short term improvement, many of whom are ineffective and even experience side effects from the medication. Dizziness, weakness, fatigue, ataxia, gastrointestinal discomfort, and abnormal liver and kidney function occur.
In recent years, some patients have been treated with botulinum toxin type A injection therapy, and some of them obtained short term effect and later relapsed. A small number of patients experienced toxic side effects of the drug, such as dizziness, weakness and dysphagia.
Patients are unable to work and study normally, have difficulty taking care of themselves, and have difficulty participating in social activities and interacting with others. Patients are mentally distressed and even lose their confidence in life.
(B) Clinical classification and typing of spastic squint
According to the posture and direction of muscle spasm, the scope and location of spastic muscles, symptoms outside the neck and systemic manifestations, spastic squint is divided into the following three categories: first, simple spastic squint, also called primary spastic squint, which involves only the neck muscles and causes only head and neck symptoms; second, complex spastic squint, which involves both spastic muscles and muscles outside the neck and causes symptoms in the neck and outside the neck. The diagnosis cannot be classified as other diseases yet; third, symptomatic spastic squint: the squint is only a local symptom of other extrapyramidal diseases, and the spastic muscles are widely distributed.
Clinical typing focuses on simple and complex spastic levator neck.
1.Typing by head and neck posture and direction
(1) Rotational spastic squint The head is rotated in the sagittal plane, the coronal plane is facing left or right, and the head and face are rotated to the left or right. The lower jaw is forced to the shoulder. In the rotational posture, some patients contain forward-flexion movement or backward-supination movement, the former is called rotational forward-flexion type, the latter is called rotational backward-supination type, and between them is called rotational horizontal type.
(2) Lateral flexion type spastic oblique neck The head and neck are tilted to the left or right, and the coronal plane of the head and neck is kept in the normal direction. The head and neck are flexed to the left or to the right, or called lateral bending. The ear is forced to the shoulder.
(3) Forward-flexed spastic slanting neck The head is tilted in front of the coronal plane or moved forward, and forward flexion or forward extension of the head and neck occurs. The head is bowed or nodded. The lower jaw is forced to the front of the chest.
(4) Posterior tilt type spastic oblique neck The coronal plane of the head and neck is tilted back, the head and face are tilted back, and the occiput is forced to the back.
(5) Mixed type of spastic oblique neck Patients with two or more of the above types of manifestations, with regular or “irregular” mixed symptoms.
Complex spastic oblique neck is classified as follows according to the involved area and nerve distribution: spastic oblique neck head and face type; spastic oblique neck thoracic type and abdominal type; spastic oblique neck upper limb type; spastic oblique neck lower limb type and spastic oblique neck spine type.
2.Types according to the degree of spasticity
(1) Light rotational and lateral flexion type of spastic squint, the rotation and lateral tilt of the sagittal plane passing through the midline of the head and neck, the angle between this plane and the sagittal plane of the normal head position is less than thirty degrees, included in light. In patients with anterior flexion and retroversion spastic squint, the angle between the coronal plane passing through the head and the coronal plane in the normal position is less than 30 degrees.
(2) Heavy The angle between the sagittal or coronal plane of the head and neck and the sagittal or coronal plane of the normal head position is greater than 30 degrees and is included in heavy spastic strabismus. In addition, patients with spastic neck that cannot be corrected by themselves, cannot engage in normal life, study and work, or have great mental stress due to spastic neck to suspend normal life and work, complex spastic neck and mixed spastic neck are all included in heavy spastic neck. (Figure 2)
3.Types according to spasticity
(1) In tonic spastic squint, the responsible muscle (i.e. spastic muscle) is in continuous spasm and can be relieved only after sleep. The movement of the slanting neck is tonic. The patient is unable to correct it on his own or can only correct it momentarily.
(2) Clonic type spastic squint is a rhythmic or irregular spasm, producing a clonic state, and the interval between spasms varies from person to person.
III. Clinical manifestations of complex spastic squint
This group of patients has the typical clinical manifestations of simple spastic squint, accompanied by local spasticity symptoms other than the neck. Again, it cannot be classified as other diseases or systemic diseases. There is great individual variation in clinical manifestations. The symptoms of simple spastic strabismus are combined with localized symptoms of muscle spasm outside the neck. For example, if the facial muscles are involved, there will be a combination of symptoms of facial expression muscles. If the throat muscles are involved, there will be difficulty in articulation, spitting, chewing and swallowing. Involvement of the chest muscles will result in chest elevation and upper extremity inversion. Involvement of the abdominal muscles will result in abdominal retraction and forward flexion of the spinal trunk. Involvement of the extremities will result in involuntary movements of the extremities. If the muscles of the lower back are involved, abnormal curvature of the spine may occur. All of the above muscle spasms may show tonic spasm or clonic two ways, clinical performance as tonic movements or clonic movements.
IV. Clinical manifestations of symptomatic spastic oblique neck
Among the extrapyramidal diseases, such as torsional spasm, hepatomegaly, chorea and other movement disorders, more or less all involve muscle spasm of the neck, causing abnormal posture and activity of the head and neck. These disorders have been clearly diagnosed; the spastic symptoms of the neck are only part of the systemic manifestations of the disease, resembling those of spastic squints, and are called symptomatic spastic squints. The symptoms of the neck are similar to those of mixed and clonic squints. The patient has widespread and asynchronous muscle spasms throughout the body, and the degree of spasticity varies, and the patient’s posture and movements are varied and complex. This includes increased muscle tone in the face, neck, throat, trunk, and extremities. Involuntary movements, uncoordinated voluntary movements, etc. Symptoms increase during emotional excitement and tension, during activity and speech. At rest and in quiet, the symptoms are reduced, and the spasticity disappears after sleep. Symptoms in the neck coexist with systemic symptoms.
V. Diagnosis
The diagnosis of spastic squint is not difficult, especially for simple spastic squint. When the patient visits the clinic and visualizes the abnormal posture and movement of the patient’s head and neck, the diagnosis will be thought of. The diagnosis focuses on whether the abnormal head and neck posture and movement is caused by muscle spasm. The muscles responsible for causing symptoms (i.e., primary and secondary spastic muscles) and the associated cervical nerves are identified, and the patient’s squint is categorized.
(i) Take medical history
(ii) Physical examination
(iii) electromyography (EMG)
(iv) CT scan of the head and neck
(v) Cervical spine radiographs
(vi) injection of botulinum toxin type A into the spastic muscle. In recent years, some patients have been treated with botulinum toxin type A injection therapy, and some patients have obtained short-term results, but later relapsed. A small number of patients showed toxic side effects, such as dizziness, weakness and dysphagia.
Differential diagnosis
(A) Hysterical slant neck
Patients are mostly young people who are mentally and emotionally fragile. The onset of the disease is mostly triggered by emotional fluctuations. The onset of the disease is sudden and rapid, and there is no obvious muscle spasm in the neck. There is no obvious muscle spasm in the neck. There is a previous similar onset. After mental reassurance, suggestion is often effective, and the symptoms disappear quickly. The type of symptoms of “squint” is often indeterminate.
(II) Congenital squint (also called myotonic squint)
The pathogenesis is perinatal hemorrhage or inflammation of the sternocleidomastoid muscle, which leads to fibrosis or partial fibrosis of the sternocleidomastoid muscle, resulting in a cord-like bulge and hardness of the sternocleidomastoid muscle on the diseased side, loss of softness and elasticity of the muscle tissue, loss of extension and contracture. This restricts the range of motion and direction of the head and neck, and the head and face rotate to the healthy side, resulting in a sloping neck. The disease duration is long and the face is asymmetrical, with the affected cheek smaller than the opposite side. The head and neck are in a forced position. There are no neurological symptoms and signs. The onset of the disease is young, and the symptoms become obvious with age.
(C) Osteogenic squint
Painful or deformed healing of the cervical vertebrae and accessories due to disease or trauma, resulting in a forced head position. History of cervical trauma, X-ray reports cervical vertebrae injury, fracture, dislocation, etc. No obvious muscle spasm. Oblique neck symptoms may disappear after early treatment of trauma. EMG, radiographs and CT scans of the neck can help to differentiate the symptoms.
(iv) Soft tissue infection of the neck forcing head position
Soft tissue infection in the neck causes headache and neck pain, resulting in forced cephalic deviation. After the infection is controlled, the symptoms of oblique neck disappear.
(V) Compensatory squint
The patient has compensatory head and neck tilted to one side due to other diseases such as strabismus and scoliosis. There is a relevant medical history without obvious muscle spasm. The head position can be corrected, but long-term strabismus or scoliosis makes the patient accustomed to the vision in the “squinted neck” position. EMG can be useful for differential diagnosis.
(F) Extrapyramidal disorders of the oblique neck
The patient may have a wide range of muscle spasms, such as torsional spasm, chorea, hepatomegaly, and other generalized motor dysfunction diseases. Cervical muscle spasm is part of the disease, and the cervical muscles are thick, hypertrophic, and high in tone. Patients start from adolescence, have a long history, poor outcome, and symptoms rise and fall with mood swings.
(vii) Motor neuron disease.
Motor neuron disease of the spinal nerve in the cervical segment or generalized motor neuron disease puts the cervical muscles in a denervated state, with decreased muscle tone, muscle atrophy, thinning of the neck, weakness in raising the head, loss of neck muscle maintenance, and head droop, sometimes mistaken for spastic slant neck. Electromyography, CT scan of the neck, and neurological examination help in differential diagnosis.
Section III Minimally invasive surgical treatment
Surgical treatment should be considered for poor drug efficacy or heavy drug toxic side effects. The principle is to achieve the best results with less trauma. Surgery is free of complications and sequelae. The author recommends cervical muscle selective resection and cervical nerve selective excision for the treatment of spastic oblique neck, and also introduces the surgical methods that have been reported publicly.
I. Selective cervical myotomy and selective cervical nerve dissection.
This is a minimally invasive procedure, and it should be preferred for primary spastic squint. The principle of surgery: to identify the major responsible muscle, the minor responsible muscle and the related nerve of spastic squint. Selective resection of the primary responsible muscle, partial resection of the secondary responsible muscle, and selective severance of the associated paraspinal nerve and posterior branch of the cervical spinal nerve are performed. The abnormal posture and movement of the head and neck can be corrected. The earliest procedures reported by foreign scholars include Isasc (1641): sternocleidomastoidectomy, Bujaski (1834): paraneoplastic nerve dissection, Keen (1891): bilateral 1 to 3 posterior cervical spinal nerve branches dissection, Finney (1925): bilateral 1 to 3 posterior cervical nerve branches and bilateral paraneoplastic nerve dissection, Bertrand (1981): 1 to 5 posterior cervical nerve branches dissection. (1981): 1~5 posterior cervical nerve branches and paraneoplastic nerve dissection, etc.
From 1960s to 1980s, he used selective resection of spastic muscles and paraneoplastic nerve dissection (i.e. duplex surgery) to treat spastic oblique neck and achieved excellent results. The new procedure for spastic squint neck was created. The surgical efficacy has been further improved. Professor Chen Xinkang has published many papers and lectured abroad at home and abroad. He has received many awards from the National Science Committee, Ministry of Health, provincial and municipal governments, and has been recognized by experts at home and abroad.
(II) Indications for surgery
1. Ineffective drug treatment: There is no specific drug for this disease, and there is no standardized drug treatment plan in clinical treatment. Once the drug is ineffective or toxic side effects occur, the drug should be stopped and surgery should be considered.
2.Optional surgery: 12 months after the onset of the disease, when the condition is more stable and the type of spastic squint can be confirmed, which is conducive to the development of a surgical plan for the individual type.
3.After the recurrence of Botulinum toxin type A injection or those who are ineffective.
4.People who can tolerate general anesthesia and have no serious dysfunction of heart, lung, liver and kidney.
5.No bleeding disease.
6.Patients with psychiatric disorders fill with surgical treatment.
7.Understand the surgical treatment and healing, and can cooperate with rehabilitation training after surgery.
(II) Surgical techniques
The principle of selective excision of spastic neck muscles and selective severance of cervical nerves, regardless of the name of the surgery, is to confirm the extent of the muscles causing spastic diagonal neck, to distinguish the primary and secondary responsible muscles, and the nerves innervating these spastic muscles. The primary responsible muscle is selectively excised and the secondary responsible muscle is partially excised. The remaining spastic muscles are denervated, i.e. the nerves innervating these muscles are selectively cut. It makes the spastic levator neck lose the role of power muscles, while preserving the function of non-spastic muscles to the maximum extent, and maintaining the normal posture and activity of the neck. The surgery conforms to the principle of minimally invasive, and an individualized surgical plan is developed according to the type of patients.
(III) Post-surgical treatment, rehabilitation and management
1.Perioperative period Pre- and post-operative work with patients and family members, inform them about the knowledge of the disease, surgical treatment measures and efficacy, several conditions and related treatment during the rehabilitation period. Relieve patients’ anxiety about the disease and establish confidence in overcoming the disease. Actively cooperate with postoperative treatment and rehabilitation training, keep the surgical cavity drainage system unobstructed, prevent blood and fluid accumulation in the cavity, and prevent infection. The drainage tube should be removed 24~72 hours after surgery, and the stitches should be removed 7~9 days after surgery.
2.Physiotherapy and physical therapy Physiotherapy and physical therapy were started 3 days after surgery. Emphasize head and neck activities to reverse the original oblique neck movement and “correct the overkill.” As long as physical strength allows, physical therapy is given several times a day, or the head and neck are held up and corrected with the help of others. Physical therapy can be used to irradiate the wound with microwave to promote wound healing and the disappearance of edema in the tissues around the trauma, and later physical therapy to promote the softening of scar tissue, which is beneficial to the free movement of the neck.
3.Several postoperative conditions and treatment
(1) The effect of postoperative treatment is “immediate”, and the symptoms of spastic squint disappear immediately after surgery. The posture is completely normal and the abnormal spastic movements no longer exist. Only a little stiffness in neck movement due to the wound was observed, and postoperative physical therapy and physiotherapy were done to assist the rehabilitation. It accounts for 40% of the surgical patients.
(2) After rehabilitation process to achieve healing Post-operative spastic squint symptoms are obviously relieved, but there are still mild squint symptoms. Analysis of the reason: There are still secondary spastic muscles and follower muscles with spasticity in the muscles preserved by the surgery. At the same time, the patient had a long medical history, tonic and stiff changes were found in the cervical spine bony joints and attachments, visual appearance of habitual strabismus, loss of balance of antagonistic muscle tone and muscle strength in the non-spastic muscles, and the above remained to be adjusted and restored for a considerable period of time after surgery. After a recovery period of several weeks to a year, symptomatic treatment with physical therapy and physiotherapy patients can achieve healing. It accounts for 45% of the surgical patients.
(3) Mild spastic strabismus symptoms remained after the rehabilitation period After a rehabilitation period of several weeks to one year after surgery, patients still had mild strabismus symptoms. The reason for this is that there are still secondary spastic muscles and follower muscles among the muscles preserved after surgery, and this part of the muscles always retains the spasticity phenomenon and causes symptoms. Later on, it developed into a major spastic muscle. Some of the cervical vertebrae, attachments and antagonistic muscles of the original spastic muscles weaken, the muscles atrophy, muscle tone and muscle strength decrease, and cannot exercise normal functions, and the symptoms of squint are difficult to overcome completely. If it does not affect life, work and study, it will not be treated, and physical therapy and physiotherapy can be done. Or local intramuscular injection of botulinum toxin type A. When the spastic muscle has been confirmed, the spastic muscle can be considered to be removed or denervated again. It accounts for 10% of the surgical patients.
(4) The symptoms of spastic diagonal neck are still more obvious or transformed or the symptoms have developed after the rehabilitation period. Analysis of the reason: The secondary spasticity and attendant muscle spasticity preserved by the surgery intensified and developed from the original secondary position to the primary position. Due to the development of the pathological basis of spastic squint, another spastic muscle is involved in the spastic action. With prolonged squinting, the cervical vertebral bony joints and attachments become degenerative and stiff. The non-spastic muscle function, decreases and the antagonistic force is weakened. There is also a generalized motor dysfunction and a mixed type of spastic squint. Postoperative outcome is compromised. In 5% of the operated patients. The principles of management, according to the postoperative symptoms, analyze and identify the muscles that drive the spasticity symptoms, the primary and secondary responsible muscles. Brain stereotactic surgery is recommended for generalized motor dysfunction disorders. For simple spastic diagonal neck can be treated by local injection therapy of botulinum toxin type A or re-operation respectively.
II. Cerebral stereotactic surgery
It is a minimally invasive technique, and the surgical method is inspired by Folz’s animal experiments. Neurologists and surgeons believe that there are focal points for spastic strabismus in structures such as the ventral lateral nucleus of the thalamus, the pallidum, the central nucleus of the thalamus and the Forel-H area. Between 1964 and 1978, Cooper, Sano, Dieckman and others reported the effectiveness of brain stereotactic surgery for spastic strabismus. More than half of the patients had efficacy, and at the same time reported different degrees of complications of the operation. Some people in China have followed the brain stereotactic surgery for spastic oblique neck.
Commentary: To date, the etiology and pathology of spastic strabismus are still unclear. Under the current technical conditions, various examinations have not revealed intracranial foci (i.e., targets) associated with spastic strabismus. There are uncertainties in the efficacy of brain stereotactic surgery, and complications are difficult to avoid completely, especially when doing bilateral brain stereotactic surgery, which has a high percentage of complications. The functional complexity of the target area destroyed by brain stereotactic surgery will have irreversible effects on the damage of other functions. Brain stereotactic surgery is difficult to cope with many types of spastic slant neck. The procedure cannot be popularized.
III. Paraneoplastic microvascular decompression
In 1986, Trackman first reported the results of a group of 33 cases. Surgical approach: craniotomy in the posterior cranial fossa. The posterior group of cranial nerves was combed at the paramedian cerebrum, and the vessels compressing the paramedian nerve were separated from the paramedian nerve. The results reached 15/33 excellent, 12/33 improved, 3/33 ineffective and 2/33 deteriorated, and no further reports in the literature since then.
Commentary: Theoretically, the paramedian nerve innervates the ipsilateral sternocleidomastoid and trapezius muscles. Even if “combing and decompression” is effective, it can only release the spasm of these two muscles. In fact, the spasticity of these two muscles is not the only one in patients with spastic diagonal neck, and there are many types of spastic diagonal neck. The correction or abolition of a single nerve cannot eliminate many muscle spasms. There is insufficient theoretical basis for this procedure in the treatment of spastic levator ani. The surgery is performed in the posterior cranial fossa, and there are reports of deaths in the literature and uncertainty about the efficacy.
IV. Chronic electrical stimulation of the spinal cord and thalamus
Cildenberg, Bertrand placed electrodes into the cervical medulla at the level of the 1st to 2nd ganglion or the ventral lateral nucleus of the thalamus, respectively, and gave certain frequency of stimulation to produce efficacy.
Commentary: Since the etiology of spastic diagonal neck is not clear, there are many types of clinical manifestations and individual differences, and the range of spastic muscles varies from type to type, the use of electrode stimulation method is theoretically open to discussion. The electrodes are made for the individual, the electrodes are implanted surgically, there are complicated technical problems in the control of the electrodes, and there are many subsequent problems, complications, loss of control and displacement of the electrodes. There is uncertainty about the efficacy. Foreign experts Goetz negated and abandoned this method by clinical control in 1988, and no one in China visited the effect.
V. Forester (1929), Dandy (1930) surgery
Under general anesthesia, the posterior cranial fossa was opened, and the 1~4 cervical laminae of the high cervical segment were resected, and the paramedian nerve and the anterior (or anterior and posterior) roots of the 1~4 cervical nerve were identified at the subdural level and cut. The muscles innervated by the paramedian nerve and the anterior (or anterior and posterior) roots of the 1~4 cervical nerve were all denervated and paralyzed. For a long time after 1929, this procedure has been used internationally as a classic procedure for specialists.
Commentary: This procedure is not minimally invasive and is very invasive. All muscles within the innervation of the paraspinal nerve and the anterior (or anterior and posterior) roots of 1 to 4 cervical nerves are paralyzed, regardless of whether the muscles are spastic or not. Normal non-spastic muscles also lose their function after surgery. Atrophy of the neck muscles, thinning of the neck profile, weakness of the cervical muscles, difficulty in swallowing, dysarthria, and limitation of neck movement. Many signs and symptoms and permanent sequelae appear that are difficult for the patient to face.