Discogenic myelopathy is a dystrophic disease of the spinal cord caused by its compression and ischemia as a result of compression of a herniated disc. Disease, depending on the level of lesion, is manifested by spastic and sluggish paresis, sensitivity disorders, pelvic disorders. Diagnosis of myelopathy caused by a herniated disc includes neurological examination, X-ray and tomographic studies of the spine, electromyography, and, if necessary, examination of cerebrospinal fluid. Discogenic myelopathy is subject to surgical treatment (laminectomy, discectomy, microdiscectomy), after which restorative treatment is carried out (medications, exercise therapy, physiotherapy, massage, reflexotherapy).
ICD 10
G99.2 Myelopathy in diseases classified under other headings
General information
Degenerative-dystrophic lesions of the spinal cord (myelopathy) can have different genesis: vertebrogenic, dysmetabolic, traumatic, atherosclerotic, tumor. The most common in clinical neurology and vertebrology is vertebrogenic myelopathy, namely discogenic myelopathy. As the name suggests, discogenic myelopathy is closely related to the pathology of the intervertebral disc. In most cases, it is a severe complication of osteochondrosis of the spine. As a rule, such discogenic myelopathy is observed in people aged 45-60 years, more often in men. It is characterized by the gradual development and aggravation of symptoms, an exciting period from several months to several years. In more rare cases, discogenic myelopathy is a consequence of spinal injury. At the same time, it has an acute course and is considered in the framework of post-traumatic myelopathy.
Causes
Degenerative changes of the intervertebral disc, which are accompanied by osteochondrosis of the spine, lead to stretching and tearing of the fibrous ring of the disc, separation of its peripheral fibers from the vertebral bodies. This leads to the displacement of the intervertebral disc with the formation of an intervertebral hernia. If the displacement is not accompanied by a rupture of the fibrous ring, then it is designated as “disk protrusion”. With the rupture of the fibrous ring and the exit of the pulpous nucleus of the disc, they speak of “disk extrusion”. Most often, the displacement of the intervertebral disc occurs in the posterolateral direction, just where the spinal cord and blood vessels supplying it pass.
Pathology develops not only due to direct compression of the spinal cord by a part of the disc that has emerged from the intervertebral space. In pathogenesis, spinal circulatory disorders may come to the fore due to compression of the vertebral arteries by an increasing intervertebral hernia. Spinal cord ischemia in discogenic myelopathy is characterized by gradual development and has a chronic character. The cause of discogenic myelopathy may be a secondary adhesive process after spinal surgery or injury. Osteophytes formed during osteochondrosis can aggravate the situation, additionally squeezing the spinal cord, its roots and vessels.
A decrease in spinal circulation due to compression of vertebral vessels and direct compression of the spinal cord lead to hypoxia and disorders of the trophic brain cells. As a result, nerve cells die in the affected area, causing the main clinical manifestations of discogenic myelopathy.
Classification
Discogenic myelopathy is classified depending on the part of the spine in which pathological changes develop. The most common is cervical discogenic myelopathy. The second most common is lumbar discogenic myelopathy. In the thoracic spine, such pathology is observed in rare cases, it is localized mainly in the lower thoracic segments.
Symptoms
The basis of the clinical picture is a gradually increasing neurological deficit of the motor and sensory spheres. Motor disorders of discogenic myelopathy are manifested by a decrease in muscle strength (paresis), accompanied by disorders of muscle tone and changes in tendon reflexes. Below the level of myelopathic changes, they are of a central (spastic) nature, and at the level of the affected segments of the spinal cord — peripheral (sluggish) character. Sensitive disorders are expressed in a decrease in surface and deep sensitivity, the appearance of paresthesia. Typical for discogenic myelopathy is the predominance of motor disorders over sensitivity disorders. At the beginning of its development, myelopathy may manifest as unilateral disorders corresponding to the side of the spinal cord lesion. Over time, there is a “transition” of symptoms to the second side. Urination disorders are possible. Often, discogenic myelopathy is accompanied by radiculitis. However, root pains are usually moderately pronounced and fade into the background in comparison with motor disorders.
Cervical discogenic myelopathy is manifested by peripheral paresis in the arms and spastic paresis in the legs. There are paresthesias in the hands, slight superficial hypesthesia and an intermittent decrease in deep sensitivity in the hands, a decrease or loss of all types of sensitivity on the trunk and legs. Muscle atrophy in the proximal parts of the arms is characteristic. Cervical discogenic myelopathy can develop in combination with vertebral artery syndrome. In such cases, along with the symptoms of myelopathy, there are signs of dyscirculatory encephalopathy in the vertebrobasilar basin: dizziness, memory loss, vestibular ataxia, noise in the head, sleep disorders, etc.
Lumbar discogenic myelopathy is characterized by peripheral paresis of the legs, accompanied by muscular atrophy, reduction or absence of knee and achilles reflexes, urinary retention and sensitive ataxia. Intermittent claudication syndrome may occur, requiring differential diagnosis with obliterating atherosclerosis and obliterating vascular endarteritis of the lower extremities.
Diagnostics
A detailed neurological examination helps the neurologist to identify signs of spinal cord damage and determine the level of its localization. For a more accurate diagnosis of the causes of myelopathy, a consultation with an orthopedist or a vertebrologist is necessary. Radiography of the spine in discogenic myelopathy determines the narrowing of the intervertebral slits characteristic of osteochondrosis, the appearance of osteophytic growths along the edges of the vertebrae. To determine the level and degree of spinal cord compression, patients with discogenic myelopathy undergo myelography. In order to visualize a herniated disc and exclude other causes of myelopathy, MRI of the spine and CT of the spine are used.
In the diagnosis of discogenic myelopathy, electroneurography and electromyography are also used. If necessary, angiography is used to assess the blood circulation of the affected area of the spine. Cervical discogenic myelopathy with signs of circulatory insufficiency in the vertebral-basilar basin is an indication for REG and ultrasound of the vessels of the head and neck.
Discogenic myelopathy requires differentiation from spinal cord tumors, vascular myelopathy, amyotrophic lateral sclerosis, spinal diseases of inflammatory genesis (myelitis), multiple sclerosis, funicular myelosis. As part of the differential diagnosis of discogenic myelopathy, a lumbar puncture can be performed. With discogenic myelopathy, there are no significant changes in the cerebrospinal fluid characteristic of other spinal cord diseases. There may be a slight increase in the protein content, but it does not reach the same degree as with spinal tumors.
Treatment
Spinal cord compression with the development of discogenic myelopathy is an indication for surgical treatment. Such conservative methods of treatment as dry and underwater spinal traction can be used in the treatment of herniated discs that are not complicated by myelopathy.
The most common operation for discogenic myelopathy is decompression of the spinal canal by laminectomy. If necessary, it can be supplemented with facetectomy. In the lumbar region, puncture decompression of the disc can be used. More radical methods of treatment, used mainly for large hernias, include discectomy and microdiscectomy.
In the postoperative period, comprehensive rehabilitation treatment is necessary, aimed at maximizing the recovery of motor functions lost due to discogenic myelopathy. It includes drug therapy (metabolites, chondroprotectors, B vitamins, anticholinesterase and vascular drugs), massage (classical and myofascial), exercise therapy, electrostimulation, hydrotherapy (coniferous, radon, hydrogen sulfide baths) and mud therapy, various types of reflexotherapy.
Prognosis and prevention
Compression of the spinal cord leads to the death of its neurons, which causes the appearance of persistent neurological deficits in the motor and sensory spheres. Only in the initial stage of discogenic myelopathy, surgical treatment and subsequent rehabilitation of patients make it possible to restore motor function. The operation performed at a later date stops the progression of myelopathy symptoms, but the formed neurological disorders, as a rule, are irreversible and lead to disability of the patient.
Prevention is reduced to the prevention and timely treatment of spinal osteochondrosis and herniated discs.
