One of the common causes of low back and leg pain is lumbar disc herniation, a disease that accounts for almost 1/3 or more of orthopedic outpatient visits, and for which there are countless treatment options. However, in general, this disease is still confusing in diagnosis and treatment. We found that for low back pain, different doctors diagnose the same patient differently; different doctors treat the same diagnosis differently; and the same disease and the same method have different effects. So, in the presence of low back and leg pain, when is a lumbar disc herniation considered? Generally, in diagnosis, three aspects should be considered – symptoms, signs and imaging, i.e. “think about the lesion by symptoms, search for the root of the disease by signs, seek confirmation by imaging, and argue one by one with contradictions”. Symptoms – pain location and attack characteristics “back pain with leg pain” is 95% of lumbar disc herniation, while “back pain with leg pain” is mostly not. The pain of lumbar disc herniation is intermittent, sometimes good and sometimes bad, sometimes for weeks or months. If the pain is persistent and worsens over time, most of it may be adhesions, inflammation, or even a tumor. There is also a certain pattern in the timing of pain episodes. The pain level of lumbar disc herniation is greater when moving than at rest, when standing than lying, during the day than at night, and lying down than lying on the side. If the pattern of pain onset is the opposite, then beware that this is not a lumbar disc herniation! Signs – bending pain is serious When lumbar disc herniation attacks, most patients have varying degrees of lumbar activity restriction, especially in the acute phase, some can not move, the pain is most obvious when bending forward, because bending can further promote the nucleus pulposus backward displacement, and increase the strain on the compressed nerve roots and increased pain. The pain is most pronounced when bending forward. In making the differential diagnosis, a straight leg raise test can also be performed, in which the patient is asked to lie supine, extend the knee, and passively raise the affected limb. In a normal person, the nerve root has 4 mm of sliding and discomfort in the N-fossa will begin to be felt when the lower extremity is elevated to 60°-70°. In patients with lumbar disc herniation, nerve root compression or adhesions reduce or eliminate the sliding degree, and sciatica can occur at elevations of 60° or less, which is called a positive straight leg raise test. If this test is positive, there is a 95% chance that the disc is herniated. In addition, there is a simple method of kneeling on a chair and touching objects on the floor, and if you cannot reach them, you also have a herniated disc. This is because most patients have varying degrees of limited lumbar movement, with the most pronounced limitation in forward flexion, which is due to the increased posterior displacement of the nucleus pulposus in forward flexion, increasing the compression of the nerve roots. Imaging examinations – X-rays cannot be missing, and MR has the highest accuracy rate Although the diagnosis of lumbar disc herniation can be made through history, symptoms and signs, imaging examinations such as X-rays, CT and MRI are still needed to exclude other diseases such as tumor and tuberculosis. X-rays cannot directly reflect the presence of disc herniation, but degenerative changes such as narrowing of the intervertebral space and vertebral body edge hyperplasia are sometimes seen on X-rays, which is an indirect indication that X-rays can show other abnormalities such as tumors and tuberculosis, so this examination cannot be missing and is necessary. In addition, CT films have a 30% false positive rate and are therefore not particularly accurate. Currently, the most effective test for lumbar disc herniation is MRI, which has an accuracy rate of 90%. It should be noted that CT and MRI without clinical manifestations alone should not be diagnosed as lumbar disc herniation. Prevention of disc herniation lies in correct posture Most lumbar disc herniations are caused by long-term unreasonable posture. The initial manifestation is just improper posture, hunching over, and excessive local stress, and over time, the nucleus pulposus tissue protrudes (or prolapses) from the rupture to compress the nerve and cause pain. Therefore, people who work long hours need to pay attention to the height of tables and chairs and change their posture regularly. People who need to bend over a lot in their professional work should regularly stretch their back and chest. Normally, you should also strengthen the lumbar back muscle training to increase the intrinsic stability of the spine, if you need to bend over to get things, it is best to use hip flexion, knee flexion squatting way to reduce the pressure on the back of the lumbar disc.