Spinal cord cervical spondylosis is caused by degeneration of the cervical vertebral body and adjacent soft tissues (such as disc herniation, bone spurs at the posterior edge of the vertebral body, ossification of the posterior longitudinal ligament, hypertrophy or calcification of the ligamentum flavum, spinal stenosis, etc.) resulting in direct compression of the spinal cord, coupled with the influence of dynamic factors such as strenuous exercise or long-term poor posture, resulting in spinal cord compression or spinal cord ischemia, followed by spinal cord dysfunction, with clinical manifestations such as numbness of the limbs Clinical manifestations include numbness of the limbs, weakness, inability to move, and a feeling of stepping on cotton when walking.
Although this type of cervical spondylosis is rare, its symptoms are serious and it develops in an insidious and aggressive manner, so it is easy to be misdiagnosed as other diseases and delay the treatment.
Etiology
There are many causes of spinal cord cervical spondylosis, which are summarized as follows.
1.Trauma
The cervical spine is located between the head and the thoracic spine, and it is the part of the human spine with the largest range of motion, so there are more opportunities for injury.
2.Chronic strain of the neck
Long-term low head work or poor posture, causing strain on the muscles, ligaments and joints of the neck, inflammatory degeneration of the affected vertebrae and joints, retroflexion of the physiological curvature of the cervical spine, instability and misalignment of the cervical spine, and protrusion of the corresponding affected vertebrae into the spinal canal, can lead to the onset of spinal cord compression.
3.Cervical degenerative changes
Old age and weakness, liver and kidney deficiency, tendons and bones slack, can cause calcification of cervical ligaments. Degenerative changes of the cervical intervertebral disc, vertebral body and small intervertebral joints are the main reason for the occurrence of cervical spondylosis. If the cervical intervertebral disc protrudes to the rear of the vertebral body, it compresses the spinal cord and causes spinal cord-type cervical spondylosis.
4.Spinal stenosis
Due to the degeneration of the cervical disc, the fibrous ring bulges into the spinal canal and the osteophytes at the posterior edge of the vertebral body protrude into the spinal canal, resulting in spinal canal stenosis. At the same time, when the vertebral space is narrowed, the yellow ligament is relaxed, the cervical spine bone joint is misaligned and destabilized, and compensatory ligament thickening and osteophytes can occur, which aggravates the occurrence of cervical spinal stenosis.
5.Obstructed intramedullary blood circulation
In pathological changes of spinal cord type cervical spondylosis, if the spinal stenosis caused is changed to a certain degree, the spinal cord can be damaged by compression, compressing the gray matter and lateral cords of the central part of the medulla where stress tolerance is weak, so that the intramedullary blood circulation is obstructed and vasodilation or even rupture occurs at the compressed parts. Local lesion tissue due to blood stagnation, tissue blood oxygen supply reduced, can appear nerve cell atrophy necrosis, empty cell degeneration and hemorrhage, etc.
6.Influence of biomechanics
Spinal cord type cervical spondylosis caused by cervical spinal stenosis can cause secondary pathological changes in the cervical spine if it is hyperextended and flexed before a clear diagnosis is made.
Subtypes
1.Unilateral compression of the spinal cord
When the spinal cord is compressed unilaterally, the typical or atypical Brown_Sequard syndrome can occur. It is characterized by increased muscle tone, decreased muscle strength, hyperactive tendon reflexes, decreased superficial reflexes, and pathological reflexes in the ipsilateral limb below the level of the lesion; in severe cases, patellar spasm or ankle spasm can be induced. In addition, there are tactile and deep sensory deficits. The contralateral side is dominated by sensory disturbances, i.e., there are temperature and nociceptive disturbances. The distribution of the disorders does not correspond to the level of the lesion. Since the motor and proprioceptive tracts on the contralateral side are still normal, the motor function on that side is normal.
2.Bilateral compression of the spinal cord
In the early stage, the symptoms are mainly sensory disorders or mainly motor disorders; in the late stage, the symptoms are incomplete spastic paralysis with different degrees of upper motor neuron or nerve bundle damage, such as unfavorable activity, unstable walking, bedridden, difficulty in breathing, increased muscle tone of the limbs, weakened muscle strength, hyperactive tendon reflexes, weakened or absent superficial reflexes, and positive pathological reflexes. Patients have a feeling of thoracic and lumbar fasciculations, and the plane of sensory alteration often does not correspond to the level of the lesion. Sometimes the plane and degree of sensory impairment on the left and right sides do not match. In some cases, the planes of sensory disturbance are distributed in a multisegmental manner. Severe cases may have sphincter dysfunction.
3.Spinal cord and nerve root mixed type
In addition to the symptoms and signs of spinal cord bundle involvement, there are also symptoms of cervical nerve roots, such as shoulder and neck pain, numbness or throbbing pain in the upper limbs, muscle atrophy, weakened biceps or triceps reflexes, and decreased finger sensation.
4.Sympathetic spinal cord mixed type
There are symptoms of spinal cord bundle and sympathetic nerve stimulation at the same time.
5.Vertebral artery spinal cord mixed type
There are symptoms of spinal cord bundle combined with symptoms of vertebral artery stimulation.
Clinical manifestations
Generally speaking, the clinical manifestations are early bilateral or unilateral lower limbs numbness, pain, stiffness and trembling, weakness, trembling, difficulty in walking, followed by bilateral upper limbs numbness, weakened grip strength, and easy loss of objects. When the above symptoms worsen, there may be constipation, difficulty in urination with urinary retention or incontinence, or bedridden, and may also be complicated by sympathetic symptoms such as dizziness, blurred vision, difficulty in swallowing, abnormal facial sweating, etc.
1. Cone bundle sign
The main feature of spinal cord cervical spondylosis is that its mechanism is due to the direct compression of the cone bundle (corticospinal bundle) by the compressor or the reduction of local blood supply. Clinically, it starts with the weakness of the lower limbs, tightness of the legs (such as leg binding) and the feeling of heavy lifting. On examination, hyperreflexia, ankle clonus, patellar clonus and muscle atrophy, which are typical symptoms of the pyramidal fasciculus, can be found. Most of the abdominal wall reflexes and testicular reflexes are diminished or disappeared. The arrangement of the pyramidal bundle in the medulla is in the order of the nerve fibers of the upper cervical extremity, thoracic, lower lumbar extremity and sacral region, which can be divided into three types: central type (upper extremity type), peripheral type (lower extremity type) and anterior central vascular type (extremity type) depending on the site of involvement.
2.Limb numbness
It is mainly due to the simultaneous involvement of the thalamic tract of the spinal cord, which is similar to the former in the order of fiber arrangement from the inside out for the nerve fibers of the upper cervical extremity, thoracic, lower lumbar extremity and sacral region. Therefore, the location and typing of symptoms are consistent with the former. The distribution of nociceptive and thermo-sensory fibers and tactile fibers in the thalamic tract of the spinal cord is different, so the degree of compression varies, i.e., nociceptive and thermo-sensory impairment is obvious, while tactile sensation may be completely normal.
3.Reflex disorders
(1) Abnormal physiological reflexes Depending on the segment of the spinal cord affected by the lesion, the physiological reflexes may change accordingly, including the biceps reflex, triceps reflex and radial aponeurosis reflex in the upper limbs, and the knee reflex and Achilles tendon reflex in the lower limbs, which are mostly hyperactive or active.
(2) Hoffmann’s sign and palmar chin reflex have the highest positive rate; later in the course of the disease, ankle clonus, patellar clonus and Babinski’s sign can appear.
4.Autonomic symptoms
Clinically, it is not uncommon that all systems are involved, among which the gastrointestinal tract, cardiovascular and urinary systems are the most common and many patients only recall that they may be caused by cervical spondylosis when their symptoms improve after decompression surgery.
5. Defecation and urinary dysfunction
At first, urinary urgency, poor bladder emptying, urinary frequency and constipation are common, and gradually lead to urinary retention or urinary and fecal incontinence.
Examination
1.X-ray plain film and power lateral film
2.MRI technique
MRI image is like a longitudinal anatomical map of the spinal cord and its surrounding tissues, which can make the local lesion clear at a glance, so it should be used in every case, which is important not only for the diagnosis and typing of cervical spondylosis, but also for the decision of surgery, the determination of the surgical site and the selection of the operation style.
3.Other
CT examination and myelography are useful for the diagnosis of this type, and can be selected as appropriate.
Clinical diagnosis
It should be analyzed with the complaints, symptoms, signs and cervical spine X-ray films to make early diagnosis.
Differential diagnosis
Some patients with spinal cord cervical spondylosis have symptoms that can be easily confused with neurogenic cervical spondylosis, neurology or internal medicine diseases.
Treatment
1.Non-surgical treatment
It is still the basic treatment for this type, especially in the early central type (upper limb type) and the former central vascular type (extremity type) patients, about half of the cases can obtain more obvious results, but the condition should be closely observed in the process, avoid any rough operation and manipulation, once the condition is aggravated, early surgery should be performed to prevent spinal cord degeneration.
2.Surgical treatment
(1) Acute progressive cervical spinal cord compression symptoms are obvious, by clinical examination or other special examination (MRICT examination, etc.);
② Longer duration of the disease, the symptoms continue to worsen and the diagnosis is clear;
③Those with moderate or mild symptoms of spinal cord compression, but no improvement for more than 1 to 2 courses of non-surgical treatment and affecting workers should be operated as soon as possible.
Prognosis
The prognosis is better in cases caused by herniated or prolapsed discs. Recurrence is rare if protection is taken after healing. The prognosis is worse for those with sagittal diameter of vertebral canal and calcification of the posterior longitudinal ligament, and the prognosis is worst for those with more than 1 year of disease and severe disease, especially those with degeneration of the spinal cord.