Thoracic spinal stenosis refers to a disease in which the thoracic spinal cord and nerve roots are compressed by congenital or acquired degenerative factors, resulting in corresponding clinical symptoms and signs. Compared to the degenerative spinal degeneration we are familiar with, such as cervical spondylosis and lumbar disc herniation, thoracic spinal stenosis is relatively less known to us, but with the advancement of diagnostic imaging technology and the continuous understanding of the disease, it is not uncommon to find thoracic spinal stenosis. Anatomical characteristics of the thoracic spine: 1. The blood supply of the thoracic spinal cord is the weak zone of the whole spinal cord, especially in the T4-T10 medullary segment, where the blood supply mainly depends on the anastomosis of the blood vessels of the corresponding vertebral segments, which is very likely to cause ischemia. Severe thoracic spinal stenosis compresses the blood vessels of the segments entering the spinal canal and sometimes causes rapid progression of the disease. 2, the normal thoracic spine has a 20-40 ° posterior protrusion, so that under normal circumstances the thoracic spinal cord is slightly attached to the anterior wall of the spinal canal, for compression originating from the ventral side of the spinal cord such as disc herniation, ossification of the posterior longitudinal ligament, etc., doing a simple posterior decompression surgery like cervical spondylosis often does not achieve the purpose of spinal cord decompression. 3, the internal diameter of the thoracic spinal canal is much narrower than that of the cervical and lumbar spinal canal, and the reserve gap of the thoracic spinal cord is very small, which often results in very rapid disease progression and at the same time puts high demands on our surgical operation. 4. The protection of the thoracic contour and the structural characteristics of the thoracic spine itself result in very little mobility of the thoracic spine, and stress concentration points are easily formed at the cervicothoracic junction and the thoracolumbar junction, and we clinically find that most degeneration-induced thoracic spinal stenosis occurs in these areas. Etiology of thoracic spinal stenosis: The most common causes of thoracic spinal stenosis are three: ossification of the ligamentum flavum, thoracic disc herniation and ossification of the posterior longitudinal ligament, which are both independent and interrelated. Thoracic ligamentous ossification: This is the most common cause of thoracic spinal stenosis, accounting for more than 80-85% of all thoracic spinal stenosis. The disease is often associated with ankylosing spondylitis, diffuse idiopathic bone hypertrophy, fluorosis and abnormal calcium and phosphorus metabolism. The disease has an insidious onset and progresses rapidly, with most patients developing before the age of 50. Thoracic disc herniation: It is the second most common cause of thoracic spinal stenosis, accounting for approximately 15% of cases, with the vast majority occurring in the lower thoracic spine. Autopsy studies and imaging studies suggest asymptomatic TDH in 11% of cases, and surgically treated TDH accounts for approximately 0,2%-2% of all thoracic and lumbar discectomies performed. In addition, studies have shown that the kyphosis angle of the corresponding and adjacent segments of thoracolumbar disc herniation is significantly greater than that of the normal population, which may lead to increased local stress and accelerated disc injury. This may lead to an increase in local stress, accelerating the damage to the intervertebral disc. OPLL is a common cause of cervical spondylosis in Asians, but is relatively uncommon in the thoracic spine because it causes compression of the ventral aspect of the spinal cord, and the posterior protrusion of the thoracic spine makes it difficult to achieve spinal cord deflation with conventional posterior decompression, and the extensive adhesion of the ossified posterior longitudinal ligament to the dura mater also affects posterior decompression. Clinical manifestations of thoracic spinal stenosis: The disease is mainly manifested as a series of upper motor neuron damage clinical manifestations of spinal cord compression, insidious onset, gradually aggravated, early only feel walking a distance, lower limb weakness, stiffness, sinking, inflexibility, etc., generally no obvious lower limb pain and numbness, rest for a moment and can continue to walk, we call it spinal cord intermittent claudication, which is different from the common lumbar spinal stenosis This is significantly different from the neurogenic intermittent claudication with pain and numbness as the main features in lumbar spinal stenosis. As the disease progresses, there is a sensation of stepping on cotton, stiffness of lower limbs, difficulty in walking, numbness and banding sensation in the trunk and lower limbs, difficulty in urination and defecation, urinary retention or incontinence, sexual dysfunction, etc. In severe cases, paralysis may occur. In some patients, the compression is located in the thoracolumbar segment and manifests as clinical manifestations of lower motor neuron damage, such as extensive lower limb muscle atrophy, lower limb weakness, and sensory loss. However, it should be noted that many patients with thoracic spinal stenosis also have a combination of cervical spondylosis or lumbar degenerative disease, which often leads to underdiagnosis or misdiagnosis of the disease, because most of the damage to the spinal cord is irreversible, and it is recommended that patients with the above-mentioned symptoms should go to a regular specialized hospital in a timely manner to avoid missing the best time for treatment. Auxiliary examinations for thoracic spinal stenosis: 1. X-ray of the thoracic spine can only detect less than 50% of OLF or OPLL lesions due to the complex structure of the thoracic spine. However, as a basic examination it can still provide a lot of important information. If a wedge-shaped change in the vertebral body is found, there may be a herniated disc; if DISH, ankylosing spondylitis, or fluorosis is found, there may be OLF; if continuous OPLL of the lower cervical spine is found, there may be OLF of the thoracic spine, etc. 2.Nuclear magnetic examination, which can clearly show the whole thoracic spine lesion and its location, etiology, degree of compression, and spinal cord damage, is the most effective auxiliary examination method to confirm the diagnosis of thoracic spinal stenosis. In addition, more than 10% of clinical cases of thoracic spinal stenosis are discovered by chance during cervical or lumbar spine MRI for OLF or thoracic disc herniation. 3.CT examination: It can clearly show the structure of bony spinal canal and ossified ligament, which provides effective information for surgical treatment. Diagnosis of thoracic spinal stenosis: The diagnosis of thoracic spinal stenosis requires a combination of clinical manifestations and imaging manifestations. First, the problem is determined to originate from damage to the thoracic spinal cord by asking about the medical history and symptoms, and then the category, location, extent and degree of the lesion are determined by corresponding imaging examinations (X-ray plain film, MRI and CT), analyzing whether there is a clear correspondence between clinical manifestations and imaging, and making a differential diagnosis with major related diseases. The diagnosis can be confirmed after differential diagnosis, especially with cervical spondylosis and lumbar spinal stenosis, and sometimes we have to develop the surgical sequence and plan when these diseases exist at the same time, which I will talk about later. Treatment of thoracic spinal stenosis: Once thoracic spinal stenosis with thoracic myelopathy is diagnosed, surgery is the only effective treatment method. After years of research, our hospital has established a set of diagnostic and treatment methods for thoracic spinal stenosis. Thoracic ligamentous ossification, “uncovering method” posterior wall resection: For this most common type of thoracic spinal stenosis, because the compression mainly originates from the posterior side of the spinal cord, the surgical method of posterior decompression is preferable. The traditional “nibbling” method of laminectomy is more likely to cause damage to the spinal cord due to the constant contact between the instrumentation and the spinal cord, and some scholars have reported that the postoperative paralysis rate is as high as 30% or more. This avoids compression and shock to the thoracic spinal cord during resection and greatly reduces the paralytic rate of thoracic spine surgery. Lateral anterior decompression surgery for herniated discs or limited ossification of the posterior longitudinal ligament in the middle and lower thoracic spine: in these two cases, the compression mainly comes from the ventral side of the spinal cord, and we use a lateral anterior approach to remove the herniated disc and/or ossified posterior longitudinal ligament via the thoracic cavity, with good clinical results. Surgical options for thoracic spinal stenosis combined with spinal cord cervical spondylosis: if the lesion is limited or close to the cervical spine, surgery can be performed simultaneously in one stage. If the lesion is extensive, surgery can be performed in stages, or the problems in the thoracic or cervical spine that cause heavy damage to the spinal cord can be solved first, and then the problems in the other parts can be solved in the second stage, when we need to carefully evaluate the main responsible segments that cause symptoms. Surgical options for thoracic spinal stenosis combined with lumbar spinal stenosis: In principle, the thoracic spinal stenosis should be addressed first. In general, compared with cervical spondylosis and lumbar stenosis, thoracic stenosis is less known, and the clinical underdiagnosis and misdiagnosis rates are very high, and the risks are much higher than those of cervical and lumbar spine surgery. We hope that this article will help to understand thoracic spinal stenosis and standardize the diagnosis and treatment of thoracic spinal stenosis.