How Does the Spinal Cord Function?

Myeloid cervical spondylosis is due to degeneration of the cervical intervertebral bone connection structure, such as disc herniation, spurs at the posterior edge of the vertebral body, hyperplasia of the articulation of the vertebrae, ossification of the posterior longitudinal ligament, hypertrophy or calcification of the ligamentum flavum, resulting in spinal cord compression or spinal cord ischemia. Spinal cord dysfunction subsequently occurs, so cervical spondylotic myelopathy is one of the symptoms of spinal cord compression and can be severely disabled, accounting for 10% to 15% of all cervical spondylosis.

Basic Information

Visiting department

orthopedics

Common causes

Cervical degeneration

Common symptoms

Spinal cord compression, numbness of arms, increased muscle tension in lower limbs, etc.

Contagious

no

Causes of cervical spondylotic myelopathy

The basic cause of cervical spondylotic myelopathy is cervical degeneration. Among the various structures of the cervical spine, cervical disc degeneration is considered to be the earliest. With the degeneration of the intervertebral disc, the water content decreases, the height decreases and the periphery protrudes, the posterior longitudinal ligament covered by the posterior disc thickens and ossifies, the osteoid hyperplasia of the vertebral body increases, and the corresponding interlaminar ligament ligament and intervertebral joint stress increase. The thickening of the ligament joint capsule and the decrease in elasticity result in the decrease of the spinal canal diameter, especially the reduction of the anterior and posterior diameter, that is, the sagittal diameter, which constitutes the static factor of spinal cord compression. Dynamic factors mainly refer to the extension and flexion of the cervical spine, which increases the stress and deformation of the spinal cord. When the cervical spine is stretched, the length of the spinal canal is shortened, the spinal cord is loosened, the spinal cord becomes "thick and thick", the cross-sectional area increases, the ligamentum ligament is folded into the spinal canal from the side, the fibrous ring and the posterior longitudinal ligament posterior process, and the spinal cord is compressed. When the cervical spine is flexed, the spinal canal is elongated, the spinal cord becomes flattened and widened, and the bowstring action moves it forward. The osteophytes in the front of the spinal canal and the protruding disc tissue press against the spinal cord and aggravate spinal cord damage. Some authors emphasize that when the cervical spine is extended, the posterior lower edge of the upper vertebral body is brought closer to the posterior upper edge of the posterior vertebral arch of the next vertebra, resulting in a "clamping" effect on the spinal cord. The pathology of spinal cord dysfunction is caused by compression of the spinal cord and blood supply to the spinal cord. The number of nerve fibers in the spinal cord is reduced, axial flow is blocked, deformed, demyelinating changes, neuronal necrosis, apoptosis, spinal cord inflammation and ischemia, etc. , Few collagen hyperplasia, scar formation or cystic change.

Chronic injury is a predisposing factor in the pathogenesis of cervical spondylotic myelopathy.

Most scholars believe that developmental spinal stenosis can reduce the threshold of cervical spondylotic myelopathy.

Clinical manifestations of cervical spondylotic myelopathy

Common performance

Spinal cervical lesions are one of the pathological changes of spinal cord compression. Clinical manifestations vary depending on the extent, location, and extent of the affected spinal cord. Sensory disorders are irregular and arm numbness is common, but objectively the pain disorder does not necessarily correspond to the dermatome dominated by the lesion. Deep sensations are rarely involved, and there may be a chest or abdominal girdle sensation, which is often accompanied by abdominal wall reflexes. Enhanced.

The upper limbs are usually damaged mainly by the following motor neuron pathways. The hands are awkward and weak. It is manifested in difficult movements such as writing, tying shoelaces buttons and using chopsticks. With the development of the disease, there may be atrophy of the internal muscles of the hand, and other upper limb muscle strength Diminish. Hoffmann sign (Huffmann sign) is mostly positive, and may have reverse radial reflex, that is, rapid flexion of the fingers caused by tapping the abdomen or biceps tendon of the brachioradialis muscle, which has the same meaning as Hoffmann sign, or appears earlier. A small number of high-grade spinal cord lesions may have increased muscle tone, hypertendinous reflexes, and other manifestations of motor neuron damage.

The lower limbs are usually abnormal in the upper motor neuron pathway, showing increased muscle tone and muscle loss, knee reflexes and Achilles tendon reflexes are active and hyperactive, and ankle, clonus, and Babinski signs are positive. Increased muscle tone, hypertenoid reflexes lead to unstable walking, especially fast walking easy to fall, gait faltering, spastic gait may occur.

Cervical spondylotic myelopathy is less likely to cause dysuria and sphincter dysfunction.

2. Performance of different lesion types

Due to the unevenness of the spinal cord compression lesions, the neurological abnormalities of cervical spondylotic myelopathy manifest as polymorphism. The lesions on both sides can be different in severity, or even on one side, but rarely occur in spinal cord transection, which is Brown_Sequard syndrome (hemelectomy syndrome), which is relatively common in intramedullary tumors.

The upper limb dysfunction is mainly manifested as nerve root symptoms, mostly the aforementioned lower motor neuron pathway disorders, and the lesions are in the center of the spinal cord and around the gray matter on both sides.

The symptoms of the lower limbs are mainly manifested as the upper motor neuron pathway disorder, which is caused by the involvement of the spinal cord in the peripheral circumference of the spinal cord. Few cases have mild or asymptomatic upper limbs and need to be distinguished from thoracic spinal stenosis.

The so-called anterior spinal cord arterial type is rare, and the onset is acute. Dyskinesia is generally lower limbs than upper limbs, and temperature and pain sensations weaken or disappear. Deep sensations are mostly normal, and hyperreflexia and pathological reflexes may occur.

Cervical spondylotic myelopathy

Film degree exam:

1.X-ray plain film and dynamic lateral film

It is beneficial to find deformities, observe cervical spine movements, and determine instability.

2.CT scan

Easy identification of ossification of ligaments

3.MRI examination

Doctors can understand the intervertebral disc, posterior longitudinal ligament, articulation of the vertebrae and the ligamentum flavum, and pathological changes of the spinal cord compression by forming a three-dimensional stereoscopic image of neural channels in the brain through sagittal and axial scans. Although myeloid cervical spondylosis manifests as multi-segment stenosis on MRI, the target intervertebra, or responsible intervertebra, usually has only one location. On the T2-weighted image, there is often a high signal in the spinal cord, which represents spinal cord compression. Pathology of changes, ischemia, inflammation and edema. MRI can also be used to detect other diseases that cause spinal cord compression, such as deformities, tumors, and tuberculosis.

Diagnosis of cervical spondylotic myelopathy

Diagnosis and differential diagnosis rely on careful collection and judgment of medical history, detailed examination, especially neurological examination, and it is not difficult to make a correct diagnosis in combination with imaging findings. Attention should be paid to the identification of neurological diseases such as motor neuron disease, syringomyelia, muscular dystrophy, and chronic alcoholic neuropathy. Don't take surgery based on spinal canal stenosis shown by radiology only. Be wary of spinal canal stenosis and neurological abnormality shown by radiology.

Spinal cervical spondylosis treatment

In view of the pathological changes of cervical spondylotic myelopathy, it is difficult to relieve spinal cord compression without surgery, and there are not many opportunities for reversal and self-limitation. If there is no contraindication to surgery, it should be considered as a surgical indication.

Regarding the surgical approach, the anterior approach or the posterior approach, decompression of the scope, laminoplasty, and fusion fixation are of different opinions.

The following issues need to be emphasized: one is to identify the target intervertebral spinal cord lesions, so that the surgery can be targeted and targeted; the other is that there is no buffer space in the spinal canal at the center of the narrow lesions. Can not reach into the bite forceps to bite, so as not to damage the spinal cord that is already in a diseased state. Third, if the disc herniation is broken, that is, softherniation, anterior decompression should be selected to remove the prominent lesions, including free debris.