I. Etiology (a) the basic etiology 1, lumbar intervertebral disc degenerative changes is the basic factor The degeneration of the nucleus pulposus is mainly manifested as a decrease in water content, and can be caused by the loss of water to the vertebral joints of the destabilization of the loosening of a small range of pathological changes; fibrous annulus is mainly manifested as a decrease in the degree of toughness of the degeneration of the annulus fibrosus. 2.Injury Long-term repeated external forces cause slight damage, aggravating the degree of degeneration. 3.Weakness of the intervertebral disc’s own anatomical factors The intervertebral disc gradually lacks blood circulation after adulthood and has poor repair ability. On the basis of the above factors, some kind of triggering factors that can lead to a sudden increase in the pressure on the intervertebral disc may cause the less elastic nucleus pulposus to pass through the annulus fibrosus that has become less tough, resulting in herniation of the nucleus pulposus. 4.Genetic factors, lumbar disc herniation has been reported to be familial, and the incidence of this disease is low in people of color. Lumbosacral congenital anomalies include lumbar sacralization, sacral lumbarization, hemivertebral deformity, small joint deformity and asymmetry of articular eminence, etc. The above factors can make the lower lumbar vertebra bear the burden of the lumbar spine. The above factors can change the stress on the lower lumbar vertebrae, thus constituting a higher pressure in the intervertebral discs and prone to degeneration and injury. （On the basis of degenerative changes in the intervertebral discs, certain factors that can induce a sudden rise in intervertebral pressure can lead to herniation of the nucleus pulposus. Common triggering factors include increased abdominal pressure, improper lumbar posture, sudden weight bearing, pregnancy, cold and moisture, and so on. Clinical staging and pathology From the pathological changes and CT, MRI performance, combined with treatment methods can be staged as follows. The fibrous ring is partially ruptured while the surface layer is still intact. At this time, the nucleus pulposus is limitedly bulging toward the spinal canal due to pressure, but the surface is smooth. This type can be relieved or cured by conservative treatment. 2. Prolapsed type: Fiber ring is completely ruptured, and the nucleus pulposus protrudes into the spinal canal, which is only covered by the posterior longitudinal ligament or a layer of fibrous membrane, with an uneven or cauliflower-like surface, which often requires surgical treatment. 3. Prolapse free type: The ruptured and protruded intervertebral disc tissue or fragments are detached into the spinal canal or completely free. This type can not only cause nerve root symptoms, but also easily lead to cauda equina symptoms, non-surgical treatment is often ineffective. Schmorl’s node: The nucleus pulposus enters into the cancellous bone of the vertebral body through the fissure of the cartilage of the upper and lower endplates. Generally, only lumbar pain is present without neurogenic symptoms, and most of the patients do not need surgical treatment. Clinical manifestations (a) Clinical symptoms 1. Lumbago is the first symptom that appears in most patients, with an incidence rate of about 91%. As the outer layer of the fiber ring and the posterior longitudinal ligament are stimulated by the nucleus pulposus, the lower lumbar pain is produced by the sinusoidal nerve, sometimes accompanied by pain in the buttocks. 2, lower extremity radiating pain Although high lumbar disc herniation (lumbar 2 ~ 3, lumbar 3 ~ 4) can cause femoral neuralgia, but clinical rare, less than 5%. The vast majority of patients are lumbar 4 to 5, lumbar 5 to sacral 1 interspace herniation, manifested as sciatica. Typical sciatica is radiating pain from the lower lumbar region to the buttocks, the back of the thighs, and the lateral calves up to the feet, and the pain is exacerbated by increased abdominal pressure such as sneezing and coughing. The radiating pain is mostly on one side of the limb, and only very few people with central or paracentral herniated nucleus pulposus show symptoms in both lower limbs. There are three reasons for sciatica: ① the ruptured intervertebral disc produces chemical stimulation and autoimmune reaction so that chemical inflammation occurs in the nerve root; ② the protruding nucleus pulposus compresses or stretches the nerve root that has been inflamed, so that the venous return of it is blocked, which further aggravates the oedema and makes it sensitive to the pain; ③ the compressed nerve root ischemia. The above three factors are interrelated and mutually aggravating. 3. Cauda equina symptoms: When the nucleus pulposus or prolapsed or free intervertebral disc tissue protrudes to the back and compresses the cauda equina nerve, the main manifestations are obstacles to urination and defecation, and abnormal sensation of the perineum and perianal area. In severe cases, symptoms such as loss of control of urination and defecation and incomplete paralysis of both lower limbs may occur, which are rare in clinical practice. (B) Signs of lumbar disc herniation 1. General signs (1) Lumbar scoliosis is a postural compensatory deformity for pain relief. Depending on the relationship between the herniated nucleus pulposus and the nerve root, the spine will curve to the healthy side or to the affected side. If the herniated nucleus pulposus is located on the inner side of the spinal nerve root, the lumbar spine bends to the affected side because bending of the spine to the affected side can reduce the tension of the spinal nerve root, so the lumbar spine bends to the affected side; on the contrary, if the protruding material is located on the outer side of the spinal nerve root, the lumbar spine bends to the healthy side more often. (2) Restriction of lumbar movement Most patients have different degrees of restriction of lumbar movement, which is especially obvious in the acute stage, with the most obvious restriction being forward flexion, because forward flexion can further push the nucleus pulposus to move backward and increase the pulling on the compressed nerve root. (3) Pressure, percussion and spasm of the sacrospinal muscles The sites of pressure and percussion basically coincide with the diseased intervertebral space, and 80% to 90% of the cases are positive. Knocking pain is obvious at the spinous process, which is caused by knocking and vibrating the lesion. Pressure points are mainly located in the 1cm of the paravertebral region, and radiating pain along the sciatic nerve may occur. About 1/3 of patients have lumbar sacrospinal muscle spasm. 2.Special Signs (1) Straight leg raising test and strengthening test The patient lies supine, extends the knee, and passively raises the affected limb. In normal people, the nerve root has a sliding degree of 4mm, and the lower limb is elevated to 60°～70° before feeling the discomfort of N fossa. In patients with lumbar disc herniation, nerve root compression or adhesion reduces or disappears the sliding degree, and sciatica can be seen when the limb is elevated to 60° or less, which is called a positive straight-leg elevation test. In positive patients, slowly lowering the height of the affected limb, to be radiating pain disappears, then passive flexion of the affected ankle joint, once again induced radiating pain is called positive strengthening test. Sometimes, because of the large nucleus pulposus, elevating the healthy side of the lower limb can also pull the dura mater to induce radiating pain from the sciatic nerve on the affected side. (2) Femoral nerve pulling test: The patient is placed in the prone position, and the knee joint of the affected limb is completely straightened. The examiner will straighten the lower limb elevated, so that the hip joint is in the hyperextension position, when hyperextension to a certain degree of pain in the femoral nerve distribution area in front of the thigh, it is positive. This test is mainly used to check patients with lumbar 2-3 and lumbar 3-4 disc herniation. 3.Neurological manifestations (1) Sensory impairment Depending on the location of the affected spinal nerve root, the sensory abnormality of the innervated area will occur. The positive rate is more than 80%. In the early stage, it mostly manifests as skin sensation allergy, and then numbness, tingling and hypesthesia appear gradually. Because the affected nerve roots are mostly unilateral with single ganglion, the range of sensory impairment is small; however, if the cauda equina nerve is involved (central type and paracentral type), the range of sensory impairment is more extensive. (2) Decrease in muscle strength 70%～75% of the patients have decreased muscle strength. When the lumbar 5 nerve roots are involved, the dorsal extension of the ankle and toes is decreased, and when the sacral 1 nerve root is involved, the flexion of the toes and feet is decreased. (3) Reflex changes are also one of the typical signs of the disease. Involvement of lumbar 4 nerve roots may cause knee-jerk reflex disorder, which is active in the early stage and then rapidly becomes hyporeflexia, while damage to lumbar 5 nerve roots has no effect on reflexes. The Achilles tendon reflex is impaired in sacral 1 nerve root involvement. Reflex changes are of greater significance to the localization of the affected nerves. X-ray film of lumbar spine can not directly react to the existence of disc herniation, but sometimes the X-ray film can see the narrowing of the intervertebral space, vertebral body edge hyperplasia and other degenerative changes, which is a kind of indirect hint, and some patients can have spinal deviation and scoliosis. In addition, X-ray film can find out whether there are tuberculosis, tumors and other bone diseases, which has important significance in differential diagnosis. 2.CT examination can clearly show the location, size and shape of the herniated disc and the displacement of the nerve root and dural sac, meanwhile, it can also show the hypertrophy of the vertebral plate and ligamentum flavum, hyperplasia and hypertrophy of the small joints, and stenosis of the vertebral canal and lateral fossa, which is of great diagnostic value for this disease and has been commonly used. 3.Magnetic resonance imaging (MRI) MRI has no radioactive damage and is of great significance to the diagnosis of lumbar disc herniation, which can comprehensively observe whether the lumbar discs are diseased or not, and through the sagittal images at different levels and transverse images of the involved discs, it can clearly show the morphology of the discs protruding and their relationship with the dural sacs and the nerve roots and other peripheral tissues, and it can also identify the existence of other space-occupying lesions in the vertebral canal. In addition, it can identify the presence of other space-occupying lesions in the spinal canal. However, it is not as good as CT examination in showing whether the herniated disc is calcified or not. Electrophysiologic tests (electromyography, nerve conduction velocity and evoked potentials) can help to determine the extent of nerve damage and observe the effect of treatment. Laboratory tests are mainly used to exclude some diseases and play the role of differential diagnosis. The diagnosis of typical cases, combined with history, physical examination and imaging, is generally not difficult, especially in today’s CT and MRI technology is widely used. If there are only CT and MRI manifestations without clinical symptoms, the disease should not be diagnosed. V. Treatment 1. Non-surgical treatment Most patients with lumbar disc herniation can be relieved or cured by non-surgical treatment. The principle of treatment is not to return the degenerated and protruded intervertebral disc tissue to its original position, but to change the relative position of the intervertebral disc tissue and the compressed nerve root or part of it back to reduce the compression on the nerve root, loosen the adhesion of the nerve root and eliminate the inflammation of the nerve root, so as to relieve the symptoms. Non-surgical treatment is mainly suitable for: ① young, first attack or short duration of the disease; ② mild symptoms, symptoms can be relieved after rest; ③ no obvious spinal stenosis in the imaging examination. (1) Absolute bed rest When the first attack occurs, bed rest should be strict, emphasizing that neither bowel movement nor urination should be out of bed or sitting up. After 3 weeks of bed rest, you can get up and move around under the protection of a waist cuff, and do not do any stooping and holding movements within 3 months. This method is simple and effective, but more difficult to adhere to. After relief, the lumbar and back muscles should be strengthened to reduce the chance of recurrence. (2) Traction therapy The use of pelvic traction can increase the width of the intervertebral space, reduce the internal pressure of the intervertebral disc, the herniated portion of the intervertebral disc is retracted, and reduce the irritation and pressure on the nerve root, which needs to be carried out under the guidance of a professional doctor. (3) Physiotherapy, massage and acupressure can relieve muscle spasm and reduce the pressure within the intervertebral disc, but note that violent massage and acupressure can lead to aggravation of the condition, and caution should be taken. (4) Corticosteroid epidural injection Corticosteroid is a long-acting anti-inflammatory agent that can reduce inflammation and adhesion around the nerve root. Generally, long-acting corticosteroid preparation + 2% lidocaine is used for epidural injection, once a week, 3 times for a course of treatment, and another course of treatment can be used after 2-4 weeks. (5) Nucleus pulposus chemical dissolution method: Collagenase or papain is injected into the intervertebral disc or between the dura mater and the protruding nucleus pulposus to selectively dissolve the nucleus pulposus and annulus fibrosus without damaging the nerve root, so as to reduce the pressure in the intervertebral disc or make the protruding nucleus pulposus smaller, thus relieving the symptoms. However, this method has the risk of allergic reaction. 2. Percutaneous Nucleotomy / Nucleus Pulposus Laser Gasification By entering the intervertebral space under X-ray surveillance with special instruments, part of the nucleus pulposus is crushed and suctioned out or gasified by laser, so as to reduce the pressure in the intervertebral disc to alleviate the symptoms, which is suitable for patients with bulging or mild herniation, and is not suitable for patients with combined lateral saphenous stenosis or those with significant herniation or those whose nucleus pulposus has already been dislodged into the vertebral canal. 3, surgical treatment (1) the indications for surgery: ① history of more than three months, strict conservative treatment is ineffective or conservative treatment is effective, but often recurring and severe pain; ② the first attack, but the pain is severe, especially in the lower limbs, the patient is difficult to move and sleep, in a forced position; ③ combined with the cauda equina compression manifestations; ④ the emergence of a single nerve root paralysis, accompanied by muscular atrophy, muscle weakness; ⑤ combined with the spinal stenosis. ⑤ Combined with spinal stenosis. (2) Surgical method: Partial removal of the vertebral plate and synchondrosis through a posterior lumbar back incision, or discectomy through the intervertebral plate space. For central herniated disc, after laminectomy, extradural or intradural discectomy is performed. In combination with lumbar instability and lumbar spinal stenosis, spinal fusion is required at the same time. In recent years, minimally invasive surgical techniques such as microdiscectomy, microendoscopic discectomy, and percutaneous intervertebral foramenoscopic discectomy have minimized surgical injuries and achieved good results. Herniated disc is caused by accumulation of injuries on the basis of degeneration, and accumulation of injuries will aggravate the degeneration of the intervertebral disc, so the focus of prevention is to reduce the accumulation of injuries. Normally, there should be good sitting posture, and the bed should not be too soft when sleeping. Long-term ambulatory workers need to pay attention to the height of the table and chair, and change the posture on a regular basis. Occupational work requires frequent bending movements, should regularly stretch, chest activities, and the use of a wide belt. Should strengthen the lumbar back muscle training, increase the intrinsic stability of the spine, long-term use of waist cushions, especially need to pay attention to the lumbar back muscle exercise, in order to prevent disuse of muscle atrophy brought about by the adverse consequences. If you need to bend down to get something, it is best to use hip flexion, knee flexion squatting mode, to reduce the pressure on the lumbar intervertebral disc posterior.