Ossification of the ligamentum flavum of the thoracic spine

Introduction to ossification of the thoracic ligamentum flavum Ossificationofligamentaflava (OLF) is very rare in clinical practice, but its clinical symptoms are complicated and misdiagnosed, delaying the timing of treatment, resulting in irreversible damage to the long-term, continuously compressed spinal cord, but in recent years with MRICT and The clinical application of CTM and other detection methods has made it easier to diagnose the early stage of ossification of the thoracic ligamentum flavum; the consequences of early diagnosis and early treatment will be significantly improved. The ratio of male to female patients is 2:1, and most of the disease after middle age is more common in Asians, especially Japanese. It is rare in Caucasians. basic knowledge Sickness ratio: 0.05% Susceptible people: no special people Mode of infection: non-infectious Complications: chronic low back pain

Causes of ossification of the thoracic ligamentum flavum

Chronic damage degeneration (40%)

Because this disease is easy to occur in people who have been engaged in heavy physical labor for a long time, and this disease mainly occurs in the middle and lower thoracic vertebrae, which is related to the large amount of activity of the middle and lower thoracic vertebrae, so that the stress of the ligamentum flavum in these parts is large and easy. Cause ossification.

Inflammation (30%)

The defense response of the living tissue with the vascular system to the injury factor is inflammation. It is what people usually call "inflammation", which is a kind of defense reaction of the body to stimulation, which is characterized by redness, swelling, heat and pain. The vascular response is the central link in the inflammatory process. In general, inflammation is beneficial and is an automatic defense response of the human body, but sometimes inflammation is also harmful, such as attacks on the body's own tissues, inflammation in transparent tissues, and the like.

Pathogenesis

Studies have shown that ossification of the ligamentum flavum is a process of cartilage internalization. The lesions began with the dura mater, the early fibrous structure was disordered, the elastic fibers decreased, the collagen fibers proliferated, swollen, and mucoid-like; the undifferentiated mesenchymal cells in the ligamentum flavum were further developed to form fibrocartilage. Cells; the final calcium salt crystals are calcified and ossified. The ossified ligamentum flavum often has four transitional areas from shallow to deep: ligamentous zone, cartilage-like zone, calcified cartilage zone, and ossification zone.

Thoracic ligamentum ligament prevention

Pay attention to rest, work and rest, prevent infection, once the disease occurs, timely treatment, early detection, early diagnosis, early treatment is the key to prevention.

Thoracic ligament ossification complications Complications chronic low back pain

Sphincter dysfunction can occur with impaired thoracic segments.

Symptoms of ossification of the ligamentum flavum in the thoracic spine Common symptoms Back pain Lower extremity radiating pain Lower extremity feeling, muscle... Ligament ossification sensory sphincter dysfunction

1. Slow onset: The disease is slow onset, concealed, and the course of disease is progressively developed, and it lasts for a long time. It can be caused by some incentives, including minor trauma or overwork, and can even worsen the disease.

2. Main symptoms: multiple symptoms of numbness and paresthesia in the lower limbs (both about 70%); unilateral or bilateral lower extremity weakness, difficulty walking (about 60% or more); 50% of patients have cotton on walking Sense; 40% of patients have chest and abdomen belt sensation or other symptoms, radiation pain, back pain, etc.

3. Signs: mainly manifested as dystrophic muscles in the unilateral or bilateral lower limbs. The sensation of the thoracic pulp damaged segment is weakened or disappeared, and may be accompanied by weakened shallow reflexes, pyramidal tract signs and sphincter dysfunction.

Examination of ossification of the thoracic ligamentum flavum

1. X-ray examination: In addition to showing different degrees of hyperplasia and degeneration of the spine, the laminar space can be found to be disappeared or blurred in the positive position, and the density is increased; the lateral slice shows the base of the lamina and the articular process. The block protrudes toward the direction of the spinal canal. Due to the occlusion of the pedicle, only the high-density shadow pointing to the intervertebral space is displayed at the projection of the intervertebral foramen. The ossification is more common in the middle and lower thoracic vertebrae, and the lesion range is more than multi-segment. (4 to 5 segments), there are also single or up to 8 segments. From the perspective of ossification, about 50% of the cases are bird's beak, the most common, followed by linear, nodules. Type and hook type.

2. Myelography: angiography can show that the corresponding level of thoracic vertebrae has complete obstruction or incomplete obstruction, and most of the obstruction occurs in the lowest and most severe ossification site.

3. CT and CTM examination: can fully reflect the morphological changes of the spinal cord, and can show the relationship between osseointegration and the structure of the spinal cord. The ossified mass in front of the lamina can protrude into the spinal canal, usually ossified in the intervertebral foramen The disc or facet joint is more prominent. According to the location and shape of the ossification, it can be divided into diffuse type (most common), lateral type (second most common) and nodular type.

4. MRI examination: mainly used to observe the relationship between ossification of the ligamentum flavum and the spinal cord, generally listed as routine examination, especially in the case of surgery.

Diagnosis and differentiation of ossification of thoracic ligamentum flavum

The diagnosis of this disease is mainly based on its clinical features, imaging findings and surgical exploration.

1. Clinical features: The disease can be seen in various segments of the thoracic vertebrae, the onset is concealed, and the clinical manifestations are mostly complicated and easily misdiagnosed, especially in the era before the emergence of CT and MRI techniques.

The early stage of the patient is mainly characterized by numbness and weakness of the lower extremity limbs, and other paresthesias, chest and abdomen belt sensation and limb tightness. The lesions are located in the upper middle segment of the thoracic spine, and may have obvious signs of upper motor neuron injury. It shows gait, increased muscle tone and positive pathological signs. At this time, the level of lesions can be determined by combining the results of chest and chest dysfunction and upper limb examination. If the lesion occurs in the lower thoracic vertebra, the incidence of ossification is high, and the degree is serious and often Combined with chest 12 ~ waist 1, or even the following level of ligament ossification or lower lumbar disease, can also involve the spinal cord and nerve roots at the thoracolumbar region. At this time, the clinical manifestations of the upper and lower motor neurons are simultaneously damaged. Mixed sputum or soft palate symptoms, which is mainly depends on the location and extent of compression, clinically should be differentiated from cervical and lumbar syndrome and other diseases of the chest and lumbar spine.

2. Imaging studies have an important role in the diagnosis of this disease.

(1) X-ray film: Anyone suspected of having this disease should take X-ray film routinely and make a preliminary diagnosis. At the same time, the possibility of other bone and joint lesions should be excluded. Thoracic vertebrae can be found on X-ray films. The ossification of the ligamentum flavum should be observed.

(2) myelography: simple vertebral angiography can only indicate the obstructive lesions and extent of the spinal canal, but can not qualitatively and comprehensively reflect the location of the lesion.

(3) CT examination: the diagnosis of this disease is the most ideal, not only can show the location, shape, size and extent of secondary spinal stenosis of OLF (especially for small ossification of small facet joints, proliferative lesions, etc.) ), and the observation of the structure of the spinal canal is more detailed.

(4) CTM examination: It can reflect the morphological changes and extent of the spinal cord, but overlaps with the contrast agent image, sometimes it is difficult to reflect the location, shape and size of the pressure-induced substance, especially the degree of ossification and the observation of nerve tissue.

(5) MRI examination: it has greater superiority, which can not only observe the sagittal plane in a wide range, but also facilitate the detection of lesions and other possible diseases in the spinal canal, but it shows poor ossified ligament cross section. And for early, small or lateral lesions are easily missed.

In summary, in terms of diagnostic accuracy, the combination of MRI and CT (or CTM) is the best choice for the diagnosis of this disease.

The disease should be differentiated from a variety of diseases, especially in the cervical spondylotic myelopathy, spinal canal occupying lesions, syringomyelia and motor neuron disorders.

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