Spinal cord cervical spondylosis is caused by degeneration of the cervical vertebrae and adjacent soft tissues (such as herniated discs, bone spurs on the posterior edge of the vertebrae, ossification of the posterior longitudinal ligament, hypertrophy or calcification of the ligamentum flavum, spinal stenosis, etc.) resulting in direct compression of the spinal cord, combined 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 such as numbness of the limbs, weakness, inability to move, the feeling of stepping on cotton when walking, etc. Wu Yongchao, Department of Orthopedics, Wuhan Union Hospital
Although this type of cervical spondylosis is relatively rare, the symptoms are serious and develop in the form of hidden invasion, so it is easy to be misdiagnosed as other disorders and delay the time of 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 skull and the thoracic spine, and is the part of the human spine with the largest range of motion, so there are more opportunities for injury, and neck trauma in adolescence is an important factor leading to the onset of the disease after middle age.
2. Chronic strain injury 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 vertebral osteoarthritis, retroflexion of the physiological curvature of the cervical spine, cervical instability, misalignment, and the corresponding posterior protrusion of the affected vertebra into the spinal canal, can lead to the onset of spinal cord compression.
3. Cervical degenerative changes
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 herniated cervical disc protrudes to the back of the vertebral body, it compresses the spinal cord and causes cervical spondylosis of the spinal cord.
4. Spinal stenosis
As a result of cervical disc degeneration, 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 stenosis. At the same time, when the vertebral space is narrowed, the yellow ligament is relaxed, the cervical vertebrae are misaligned and destabilized, and compensatory ligament thickening and osteophytes may occur, which aggravates the occurrence of cervical spinal stenosis.
5. Intramedullary blood circulation is obstructed
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 compressively damaged, compressing the gray matter and lateral cords and other parts of the central part of the medulla where stress tolerance is weak, so that the intramedullary blood circulation is blocked, and vasodilation or even rupture occurs at the compressed parts. Local lesion tissue due to blood stagnation, tissue blood and oxygen supply is reduced, there may be atrophy and necrosis of nerve cells, empty cell degeneration and hemorrhage, etc.
6. Biomechanical effects
Spinal cord-type cervical spondylosis due to cervical spinal stenosis can cause secondary pathological changes in the cervical spine if it is hyperextended and flexed before a clear diagnosis is made.
Classification
1. Unilateral compression of the spinal cord
When the spinal cord is compressed unilaterally, a 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 may 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, respiratory difficulty, increased muscle tone of the limbs, reduced muscle strength, hyperactive tendon reflexes, reduced 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. In severe cases, there may be sphincter dysfunction.
3. Mixed spinal cord and nerve root 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 tract 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 irritation.
Clinical manifestations
Generally speaking, the clinical manifestations are numbness, pain, stiffness and shaking, weakness and trembling of the lower limbs bilaterally or unilaterally at the early stage, difficulty in walking, followed by numbness of the upper limbs bilaterally, weakened grip strength, and easy loss of objects. When the above symptoms are aggravated, there may be constipation, difficulty in urination with urinary retention or incontinence symptoms, or bedridden, and may also be complicated by sympathetic symptoms such as dizziness, blurred vision, difficulty in swallowing, and abnormal facial sweating
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, etc. Gradually, symptoms such as drifting, limping, easy kneeling (or falling), inability to lift the toes off the ground, clumsy gait and the feeling of chest binding appear. On examination, typical symptoms of the pyramidal fasciculus such as hyperreflexia, ankle clonus, patellar clonus and muscle atrophy can be found. Most of the abdominal wall reflexes and testicular reflexes are diminished or disappeared, and objects held in the hand can easily fall down (indicating that the deep part of the pyramidal fasciculus is involved). 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 to 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 deficits are 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) Presence of pathological reflexes Hoffmann’s sign and palmar chin reflex have the highest rate of positivity; ankle clonus, patellar clonus and Babinski’s sign may appear in the later stage of the disease.
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
Most of them appear in the late stage, initially with urinary urgency, poor bladder emptying, urinary frequency and constipation, gradually leading to urinary retention or urinary and fecal incontinence.
Examination
1. X-ray plain and power lateral films.
2. MRI technique
MRI images are like a longitudinal anatomical map of the spinal cord and its surrounding tissues, which can make the local lesions visible at a glance, so it should be used in every case.
3. Other
CT examination and myelography are useful for the diagnosis of this type and can be selected at your discretion.
Diagnosis
The clinical analysis should be combined with complaints, symptoms, signs and cervical spine X-rays to make an early diagnosis.
Treatment
1. Non-surgical treatment
The current majority view is that non-surgical treatment of spinal cervical spondylosis is not effective. In the process of observing the condition, any rough operation and manipulation should be avoided, and once the condition worsens, early surgery should be performed to prevent spinal cord degeneration.
2. Surgical treatment
(1) Selection of surgical cases ① Acute progressive cervical spinal cord compression symptoms are obvious and should be operated as soon as possible if confirmed by clinical examination or other special examination (MRICT examination, etc.); ② Longer duration of the disease, symptoms continue to worsen and the diagnosis is clear; ③ Spinal cord compression symptoms are moderate or mild, but no improvement by non-surgical treatment for more than 1 to 2 courses and affect workers.
(2) Surgical approach and operation style The most effective surgical approach and operation style will be selected depending on the condition, patient’s general condition, operator’s technique and operation habit. In principle, the anterior approach is adopted for those with symptoms of conus pressure, while the posterior cervical approach is adopted for those with sensory impairment and cervical spinal stenosis. For patients with herniated or prolapsed nucleus pulposus, nucleus pulposus removal should be performed first, followed by internal fixation with bone graft fusion or artificial disc implantation as appropriate. The operation should be performed with sufficient decompression to minimize the damage to the stability of the vertebral segment.
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 a significantly narrowed sagittal canal with large bone spurs or 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.
(From Baidu, slightly modified)