1. Etiology and characteristics Chronic low back pain in the elderly has a long history, often recurrent, and is easily induced or aggravated by exertion, improper exertion, coughing, squatting or rising, etc., with no obvious history of trauma. Intervertebral disc bulge (herniation) is one of the most common causes of geriatric low back pain. The normal lumbar disc consists of the annulus fibrosus, nucleus pulposus and upper and lower cartilage plates. Among them, the nucleus pulposus is located in the center of the disc and is mainly composed of collagen, aminopolysaccharide protein and chondroitin sulfate, etc. This structure makes the nucleus pulposus have great water content, elasticity and shock cushioning effect, which can make the spine evenly loaded under pressure. The water content is important to maintain the function of the nucleus pulposus. The water content of the nucleus pulposus can reach 80% to 85% in childhood, but gradually decreases to about 70% in adulthood, and the decrease in water content makes the nucleus pulposus less able to cushion shock, and more stress will be applied to the annulus fibrosus and other adjacent structures, which changes the normal local mechanical relationship and gradually causes degeneration of the lumbar spine. After disc degeneration, the role of the nucleus pulposus in bearing and buffering stress decreases, and more stress will act on the surrounding tissues, especially more stress will be generated in the annulus fibrosus, and its stress pattern will change from alternating tension and pressure to continuous stress, which is more likely to produce fatigue injury and increase the factor of local segmental instability. At the same time, the gradual decrease in the content of amino polysaccharide protein in the nucleus pulposus tends to fibrosis and reduces its elasticity and expansion; the fibrous ring is partially degenerated and broken, losing its original level and toughness, and the attachment point is relaxed; the cartilage plate becomes thin, ruptured, incomplete and cystic degeneration, and the chondrocytes are necrotic; in addition, as the water content of the nucleus pulposus decreases, the intervertebral disc gradually loses its normal height and the intervertebral space becomes extremely narrow. The above factors can change the local mechanics of the lumbar spine, resulting in irregular and excessive movements of the adjacent vertebrae, and such irregular movements can pull the fibrous ring, stimulate local bleeding, mechanization, calcification, ossification and formation of bone superfluous, and the small intervertebral joints also become hypertrophic due to the increased load, sometimes accompanied by subluxation of the joints. In addition, the narrowing of the intervertebral space leads to relaxation and bulging of the fibrous ring in all directions, and the ligamentum flavum also relaxes and thickens due to increased stress, all of which are factors causing the narrowing of the spinal canal and the nerve root canal, and the increased stress can also lead to the occurrence of lumbar isthmus and lumbar spondylolisthesis. Osteoporosis is also a common cause of low back pain in the elderly. The occurrence of osteoporosis in the elderly is partly due to the aging of the body, but more importantly due to the change in the level of sex hormones in the body, so the incidence is higher in women than in men. It is generally believed that the back pain of osteoporosis patients is not caused by osteoporosis itself, but is mostly caused by the degenerative degeneration of the spine secondary to or accompanying osteoporosis, and the root cause of the symptoms is degenerative degeneration of the spine. Therefore, in addition to the treatment of osteoporosis itself, should also be aimed at the treatment of various spinal degeneration factors. 2, the choice of treatment methods elderly patients with low back pain are more poor health, often suffering from some internal diseases, so the pain is light, the short history of the disease can first consider conservative treatment. This is effective for most patients and can control or relieve the symptoms of low back pain, which is the basis of subsequent treatment. On this basis, local physiotherapy, oral anti-inflammatory and analgesic drugs, intermittent lumbar traction and lumbar girth fixation are combined, and after the symptoms are relieved, lumbar muscle exercise is performed appropriately. Although the above conservative treatment has different degrees of effect on most patients, palliative treatment cannot effectively prevent the recurrence of symptoms. Therefore, as long as the physical condition allows, we advocate active surgical treatment in cases where conservative treatment has been repeatedly performed with poor results, where nerve roots are significantly compressed due to disc herniation, or where clear spinal stenosis factors exist. Based on the characteristics of less physical work and lighter spinal load in the elderly, some scholars often prioritize the complete removal of the causative factors to fully decompress the spinal canal and nerve roots during surgery, while less consideration is given to postoperative spinal stability. However, too much destabilization of the lumbar spine is not conducive to the elimination of clinical symptoms, and is not conducive to the assurance of long-term results. We mostly use unilateral or bilateral interlaminar opening or hemilaminectomy with nucleus pulposus removal to remove the nucleus pulposus while completely removing the intervertebral ligament, enlarging the lateral saphenous fossa, and opening the nerve root canal, which can fully decompress and release the nerves in the spinal canal while maximizing the stability of the spine, overcoming the disadvantages of incomplete decompression by simple interlaminar opening and postoperative spinal instability by total laminectomy. Total laminectomy should be considered only in cases of partial extensive spinal stenosis and central disc herniation combined with central spinal stenosis, and the spinous process and interspinous ligament should be preserved as much as possible during surgery to maximize the stability of the posterior spine. The pedicle screw technique has been recognized as an effective means of reconstructing spinal stability, and good spinal stability is important in preventing recurrence of postoperative symptoms. In our group of 23 patients with lumbar spinal canal decompression followed by internal fixation of the pedicle, the postoperative symptom improvement, especially the long-term effect, was significantly better than that of those with simple decompression without internal fixation. In conclusion, age-related disc degeneration and osteoporosis are the main causes of low back pain in the elderly. On the basis of conventional conservative treatment, aggressive surgical treatment can achieve good clinical results. During surgery, we should emphasize the thoroughness of nerve root decompression by spinal canal decompression and also pay attention to the maximum preservation of the stability of the lumbar spine. With the popularization and improvement of surgical techniques, the application of internal fixation of the pedicle will play an increasing role in preserving the stability of the lumbar spine in the treatment of geriatric low back pain surgery.