1.Why do I need lumbar fusion? The stability of the spine plays an important role in maintaining the physiological function of the body. Spinal stability reconstruction is necessary for all conditions or disorders that cause loss of lumbar stability, including lumbar isthmus fractures, degeneration, trauma, congenital disease, pathologic disruption, surgical removal of too many articular processes for disc herniation and extensive laminectomy decompression for spinal stenosis. All kinds of internal fixation, no matter how strong they are, the stability they establish is temporary. With the passage of time, its fixation effect will gradually weaken until it is lost, and the stability established by it will be lost. Only through bone graft fusion can permanent stability be achieved and real stability be reconstructed. Therefore, bone graft fusion plays a key role in rebuilding the stability of the lumbar spine, and the success of fusion has become one of the important signs of successful spinal surgery. 2.What are the common procedures of lumbar spine fusion? Commonly used lumbar fusion techniques and their characteristics: There are various lumbar fusion techniques, which are broadly divided into three categories according to the different fusion sites: posterior lateral fusion, posterior lateral fusion and interbody fusion. (1), lumbar posterior fusion: posterior fusion was first reported by Hibbs in 1911, so also known as Hibbs fusion, is a bilateral fusion between the vertebral plate and the articular process, its indications are very limited, can only be applied if the vertebral plate remains intact. Nowadays, it is rarely used and has been largely eliminated. (2), lumbar postero-lateral fusion: that is, intertransverse fusion, compared with Hibbs fusion, PLF has wider indications and was once used as the standard procedure for lumbar fusion, but it suffers from large trauma, serious paravertebral muscle damage, cannot effectively restore the height of the intervertebral space and the physiological curvature of the lumbar spine, cannot perform lumbar slippage reset, cannot effectively restore the support function of the anterior column of the lumbar spine, difficult to handle the bone graft bed, and requires a large amount of bone graft. It requires more bone graft, low fusion rate, low fusion strength and difficult evaluation of bone graft fusion, etc. (3), lumbar interbody fusion: LIF was first reported by Cloward in the 1950s. It can effectively restore the anterior column support function of the lumbar spine and reconstruct the physiological curvature of the lumbar spine, so it is more in line with the physiological function of the lumbar spine. Compared with other fusion techniques, its bone graft area is significantly larger, the fusion rate is significantly higher, and the fusion strength is also significantly higher, while discogenic pain caused by disc lesions is eliminated. There are three main types of LIF according to the surgical access: anterior interbody fusion, posterior interbody fusion, and transforaminal interbody fusion. Nowadays, most of the lumbar fusion procedures received in our department are transforaminal intervertebral fusion, which is fast, less bleeding, and significantly less complications.