The treatment of lumbar spinal isthmus is not aimed at curing the isthmus, but at improving spinal stenosis, reducing the symptoms of nerve compression, and improving the quality of life; because there are no clinical symptoms, part of the isthmus does not require treatment, and the treatment is basically surgical according to the presence or absence of vertebral slippage; (a) The principles of lumbar spinal slippage treatment include the following: ① Not all lumbar spinal slippage requires treatment. In fact, a significant proportion of patients with lumbar spondylolisthesis have no symptoms of lumbar pain throughout their lives and are untreated; the latest research results confirm that the degree and type of chronic lumbar pain in patients with acquired lumbar spondylolisthesis are not substantially different from normal people. ②Lumbar spondylolisthesis with low back pain does not always require surgery. For patients with lumbar spondylolisthesis who have symptoms of low back pain, first of all, the location and nature of the pain should be clarified to determine whether the pain is related to the spondylolisthesis, because degeneration of the disc adjacent to the spondylolisthesis, small joint lesions or soft tissue injuries can lead to low back pain; symptomatic treatment or experimental treatment, such as braking and physiotherapy, should be carried out to address the causes; if conservative treatment is ineffective or if the pain is determined to be related to the spondylolisthesis, then surgery should be considered. If conservative treatment is not effective or if the pain is determined to be related to the slippage, surgery should be considered. If conservative treatment fails or if the pain is determined to be related to the slippage, surgery should be considered. It is important to make a comprehensive evaluation of the patient’s age, the type of slippage, the degree of slippage, and the state of the intervertebral disc and spinal canal before surgery, so as to select the appropriate surgical method with a view to achieving the expected results. The ultimate goal of surgical treatment is the fusion of the slipped vertebrae. For patients with lumbar spondylolisthesis, an ideal operation should include decompression of the compressed neural tissue, repositioning and internal fixation of the slipped vertebral body, and fusion of the slipped vertebral body with the adjacent vertebral body. (ii) Non-surgical treatment of lumbar spondylolisthesis is suitable for patients with a short history, mild symptoms, no obvious slippage, patients with simple isthmic fracture and patients who are too old and poor in constitution to tolerate surgery. Non-surgical treatment mainly includes: rest physiotherapy, lumbar back muscle exercise, lumbar girth or brace, symptomatic treatment, etc. After standardized conservative treatment, most patients can have their symptoms relieved. (3) Surgical treatment of lumbar spondylolisthesis Indications for surgery: (1) No or symptomatic; slippage greater than 50%; adolescents in the growth period (2) Progressive slippage (3) Non-surgical treatment cannot correct spinal deformity and gait abnormalities (4) Non-surgical treatment cannot relieve pain (5) Lower extremity neurological symptoms or cauda equina compression syndrome. The principles of surgery for slippage are: decompression, repositioning, fusion and stabilization of the spine. The purpose of surgery is to relieve the patient’s symptoms, so we must accurately determine the cause, location and extent of the symptoms before surgery, and focus on several steps such as decompression, fixation and fusion, and then combine them with relevant imaging examinations to develop a reasonable surgical plan. 1.Decompression Decompression is the main means to relieve symptoms. It is controversial whether nerve root decompression is needed for mild lumbar spondylolisthesis. For severe slippage, most authors advocate nerve decompression to relieve symptoms. The scope of decompression should include the ligamentum flavum, intervertebral discs, hyperplastic synapses, lateral saphenous fossa and, in cases of spinal stenosis, vertebroplasty. In addition to relieving the compression of the dura and nerve roots, decompression also facilitates the repositioning of slippage. Since decompression destroys the posterior column structure of the lumbar spine and weakens the stability of the spine, fusion should be performed at the same time. The intervertebral disc is an important structure to maintain intervertebral stability, so it is necessary to clarify whether the symptoms are related to the intervertebral disc before surgery and try to preserve the useful intervertebral discs, which can reduce the surgical trauma and operation time. 2, reset So far, there is a big controversy on whether the slipped disc needs to be reset. At present, most scholars in China believe that in principle, we should try to reset; if we cannot reset completely, partial reset can also be done. The advantages of resetting the slipped spine are: (1) restoring the physiological curvature and weight-bearing curve of the lumbosacral spine, and the normal weight-bearing curve has the effect of promoting bone fusion. (2) There is a relatively wide bone graft bed after resetting, which is conducive to bone graft fusion. (3) It can relieve the pulling of nerve roots and reduce the complications of nerve damage. (4) It restores the normal biomechanical relationship of the spine, reduces the slip shear of the slipped vertebral body on the inferior vertebral body, and stabilizes the spine; and relieves the secondary lower back pain due to the improvement of the lesions of the joint capsule, ligaments, and muscles. Surgical repositioning should be performed on the basis of adequate decompression, which makes repositioning simpler and easier with no nerve compression and relaxation of the intervertebral structures. With the development of spinal instrumentation, it is no longer a problem to reset for severe slippage. 3, internal fixation Strong internal fixation not only helps to prevent the progression of deformity and improve the early and mid-term clinical outcome; it also increases the fusion rate of the spinal canal. But the anterior surgery can not use internal fixation. The arch nail can achieve three-column fixation, can be braced, lift and reset, its anti-rotation, shear performance is very strong, so is the main use of posterior surgery internal fixation. Since the invention of the pedicle screw by Roy-Camille 30 years ago, there have been significant improvements in the material, shape, rod attachment, fixation, and repositioning of the pedicle nail instrumentation. Modern pedicle screws are accurate, simple to operate, strong, easy to reposition, and have high resistance to rupture and fatigue. 4.Fusion The lumbar spondylolisthesis fusion is divided into anterior, posterior fusion and combined anterior and posterior surgery according to the surgical approach; it is divided into isthmus repair, lamellar bone graft fusion, interbody fusion and lateral and posterior bone graft fusion according to the bone graft site. Simple isthmus repair and fusion can preserve the motion function of the diseased segment, with little interference to the normal physiological range of motion of the lumbar spine, little surgical trauma and simple operation technique. However, the indications for surgery must be strictly controlled, and special attention should be paid to the following two points: ① Only for patients with simple isthmic fracture. It is not indicated for patients with combined slipped vertebrae, even if they are mild, or for patients with combined disc herniation or spinal stenosis requiring extensive decompression. ② For adolescent patients. For those older than 30 years, direct repair is difficult to achieve success. Posterior laminar fusion includes matchstick implants and large H-shaped implants, pioneered by Albee and Hibb in 1911, but now less commonly used because of the high incidence of pseudoarthrosis. Interbody fusion has the advantages of large bone graft volume, rapid fusion, high fusion rate, support of the anterior vertebral column and maintenance of spinal stability. From a biomechanical analysis, interbody implant fusion is theoretically the ideal method for repairing the anterior mid-column. The main procedures of interbody fusion are trans-anterior approach (ALIF), posterior approach (PLIF), and transvertebral foraminal approach (TLIF). The advantages of ALIF are the ability to perform repositioning and fusion with bone grafting under direct vision. The disadvantages of this procedure are the high operator requirements, the high injury, the tendency to cause sexual dysfunction and postoperative adhesions and other complications, and the inability to relieve neurological symptoms caused by posterior compression of the spinal canal. The advantages of posterior interbody fusion (PLIF) are: (1) the stability of the spine can be preserved or enhanced (2) the bone grafting operation is simple and easy (3) the stability of the spine can be determined after fusion (4) the decompression is complete (5) the postoperative complications are less. However, the procedure has an increased possibility of damaging the dura mater and nerve roots. Transvertebral foraminal approach interbody fusion (TLIF) is a new technique that has emerged in recent years and has the tendency to gradually replace PL IF. The main features of this technique are (1) unilateral posterior and lateral access to the intervertebral space, feasible bilateral anterior intervertebral bone graft support, less traumatic than the bilateral access intervertebral bone graft in PLIF, reduced operative time and less bleeding. (2) The TLIF procedure preserves the supraspinous and interspinous ligaments and the posterior longitudinal ligament, which can act as a tension band for the vertebral implant and promote fusion by compressing the implant; at the same time, it can prevent the implant from falling backward into the spinal canal. (3) The TLIF procedure only removes the small joint on one side, preserving the vertebral plate and the small joint on the other side, so that the integrity of the vertebrae is relatively less damaged, and increases the area of bone graft during surgery, thus improving the fusion rate of bone graft. (4) No traction on the dura and nerve roots is required, which will not cause damage to the nerve roots, cauda equina and round vertebrae. The advantages of lateral posterior fusion (PLF) are: (1) decompression surgery can be performed at the same time (2) the bone graft site is closer to the flexion and extension axis of the lumbar spine, and the surrounding blood circulation is rich, which is conducive to bone healing (3) the postoperative bed rest time is relatively short (4) it can be used simultaneously with interbody bone graft and plate bone graft for 360° fusion. However, the fusion pseudo-joint formation rate of lateral posterior implant is high; the postoperative posterior lateral implant area is under strong tension, and under the effect of long-term repeated shear stress, elongation of the fusion area or fatigue fracture may occur, causing further development of lumbar spondylolisthesis. There are many materials available for intervertebral implants, including Cage and Spacer, in addition to the traditional autologous and allogeneic bone blocks, and the intervertebral fusion device (Cage) has developed rapidly since its application 10 years ago. The shape has changed from a threaded cylinder to a square and box shape, and the material has changed from titanium to carbon fiber and the more biocompatible PEEK.