Thoracic spinal stenosis refers to a disease in which the thoracic spinal cord and nerve roots are compressed due to congenital or acquired degenerative factors, resulting in corresponding clinical symptoms and signs, and is relatively less known than the degenerative spinal degeneration we are familiar with, such as cervical spondylosis and lumbar disc herniation. Many patients with thoracic spinal stenosis have a combination of cervical spondylosis and lumbar spondylosis, which often leads to misdiagnosis and underdiagnosis, but the special anatomical and physiological characteristics of the thoracic spinal canal and thoracic spinal cord lead to a high rate of paralysis. However, the special anatomical and physiological characteristics of the thoracic spinal canal and thoracic spinal cord lead to a high paralysis rate and great surgical risk, and many spine surgeons consider thoracic spine surgery as a restricted area. The anatomical characteristics of the thoracic spine: 1. The blood supply of the thoracic spinal cord is the weak area of the entire 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 can easily cause ischemia. 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 puts forward extremely high requirements for our surgical operation. 4. The protection of the thoracic contour and the structural characteristics of the thoracic spine itself lead to 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 degenerative thoracic spinal stenosis (such as thoracic disc herniation and ossification of the ligamentum flavum) occurs in these areas. 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 (OLF): This is the most common cause of thoracic spinal stenosis, accounting for more than 80-85% of all thoracic spinal stenosis, and although a great deal of research has been conducted, its etiology is still not very clear. The disease is often associated with ankylosing spondylitis, diffuse idiopathic bone hypertrophy, fluorosis, and abnormal calcium and phosphorus metabolism. The disease is insidious and progresses rapidly, with most patients developing it before the age of 50. Thoracic disc herniation (TDH): 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% to 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 increased local stress and accelerated disc injury. Posterior longitudinal ligament ossification (OPLL): relatively uncommon, accounting for about 5% of cases, but the most difficult cause to manage, OPLL is a common cause of cervical spondylosis in Asians, but is relatively uncommon in the thoracic spine because OPLL causes compression of the ventral aspect of the spinal cord and posterior protrusion of the thoracic spine makes it difficult to achieve spinal cord deflation with conventional posterior decompression, and extensive adhesion of the ossified posterior longitudinal ligaments to the dura mater also affects posterior decompression. The effect of posterior decompression is also impaired by the extensive adhesion of the ossified posterior longitudinal ligament to the dura. 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 for a distance, lower limb weakness, stiffness, sinking, inflexibility, etc., generally no obvious lower limb pain and numbness, rest for a few moments and can continue to walk, we call it spinal cord intermittent claudication, which is different from the common lumbar spinal stenosis in which pain and numbness are the main causes. 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 (OLF) – “uncovering” posterior wall resection: For this most common type of thoracic spinal stenosis, since the compression mainly originates from the posterior aspect of the spinal cord, posterior decompression is the best surgical method, and the traditional “nibbling” method of vertebral plate resection is the best. The traditional “nibbling” method of laminectomy is very likely to cause damage to the spinal cord due to constant contact between the instruments and the spinal cord, and some scholars have reported that the postoperative paralysis rate is as high as 30% or more. However, attention must be paid to the extent of decompression, generally to the segments without spinal cord compression, and the use of high-speed grinding drills instead of bone knives and biting forceps during the resection process, which avoids compression and shock to the thoracic spinal cord during the resection process and greatly reduces the paralysis-causing rate of thoracic spine surgery. Middle and lower thoracic disc herniation (TSH) or limited ossification of the posterior longitudinal ligament (OPLL) – lateral anterior decompression surgery: in both cases, the compression is mainly 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 through the thoracic cavity with good clinical results. Osteosynthesis of the posterior longitudinal ligament of the upper thoracic spine (OPLL) combined with ossification of the ligamentum flavum (OFL) – “cul-de-sac collapse method” 3600 spinal cord circumferential decompression: This type of compression is characterized by 360-degree circumferential compression, the upper thoracic spine has a physiological posterior convexity, and the anterior compression still exists with simple posterior decompression, and the anterior major root artery of the spinal cord cannot be extended The anterior decompression method is reported in the domestic and foreign literature to use splitting the sternum or clavicle and accessing from the large blood vessel gap, which is complicated and risky, and the domestic and foreign literature reports that the spinal cord damage is aggravated by 30% immediately after surgery. The operation is complicated, with a lot of bleeding, and it is easy to damage the vertebral segmental arteries, which increases the risk of immediate spinal cord damage aggravation, so we innovatively proposed the “cul-de-sac collapse method” 3600 spinal cord circumferential decompression from 2007. The posterior wall of the vertebral body was first resected by the “uncovering method”, using ultrasound to detect the OPLL segment that was still significantly compressing the spinal cord from the front after posterior decompression, followed by removal of the remaining articular eminence at the OPLL segment, separation and protection of the intercostal nerve, high speed grinding and scraping along the vertebral arch to the vertebral body to the level of the posterior wall of the vertebral body, and then probing for The dural adhesions were explored, and the cancellous bone of the posterior 1/4-113 of the vertebral body was excavated at 60° obliquely from both sides of the posterior wall of the vertebral body with a high-speed grinding drill and scraping spoon to form a “cul-de-sac” with left and right penetration. Depending on the degree of adhesion between the dura and the OPLL, a homemade hook knife is used to sharply or bluntly separate the dura, and in severe cases, part of the dura can be removed to separate the OPLL from the spinal cord dura, and the unossified posterior longitudinal ligament is cut at the top of the OPLL, and the wall of the “culvert” formed by the OPLL is collapsed with a peeler to remove the OPLL block from the lateral posterior side to complete the decompression of the anterior spinal cord. Ultrasound was used again to ensure adequate decompression of the anterior aspect of the spinal cord. Since 2007, we have completed 71 cases of this type of surgery, and there has not been a single case of paralysis, reaching the international leading level. The choice of surgery for thoracic spinal stenosis combined with spinal cord cervical spondylosis: if the lesion is limited or close to the cervical spine, the surgery can be performed simultaneously in one stage, if the lesion is extensive, the 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 segment that causes the 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.