The lumbar disc herniation produces edema mainly due to the following reasons: 1. When the lumbar disc protrudes posteriorly, it compresses the dural sac or the spinal cord, and when the dural sac is compressed, it causes abnormal venous return to the surface, resulting in impaired blood circulation, which leads to local edema due to abnormal venous return. 2. When the lumbar disc protrudes laterally and posteriorly, it compresses the nerve roots, and when the nerve roots are compressed, the same problem exists. The same problem exists when the nerve roots are compressed, that is, the venous return of the nerve roots is compressed, so that the venous return is obviously obstructed, and this will lead to obvious edema of the nerve roots. 3. The lumbar intervertebral disc is a protein in nature, and the protein of the lumbar intervertebral disc will stimulate and compress the nerve roots to produce chemical edema of the nerve roots, so there will be symptoms of edema after suffering from lumbar disc herniation.