Lumbar spinal stenosis refers to the symptoms caused by abnormalities of bony fibrous structures in the lumbar spinal canal cavity for some reasons, resulting in narrowing of one plane or multiple planes or multiple canal cavities and compression of cauda equina or nerve roots. It is mostly caused by the degeneration of the lumbar spine with disc herniation, bone superfluous hyperplasia at the posterior edge of the vertebral body, hyperplasia and coalescence of small synapses, and hypertrophy of the ligamentum flavum, which mainly manifests clinically as low back pain, lower limb pain, numbness and even dysfunction, mostly accompanied by intermittent claudication (gradually increasing heaviness, weakness, swelling and numbness, and pain in the lower limbs after standing upright or walking a distance of 50~200m, which improves after a few minutes of rest with a slight bending or squatting). Surgery is required when conservative treatment is ineffective. The ultimate goal of surgical treatment is to completely decompress the narrowed part of the spinal canal and release the nerve root compression. The traditional surgical approach requires extensive stripping of the vertebral muscles and ligaments in order to provide a surgical field of view, which is more traumatic and bleeds more, and is prone to postoperative low back pain due to muscle atrophy. At the same time, extensive muscle stripping is prone to delayed healing or even infection of the incision due to the accumulation of fluid in the dead space when the incision is closed. The expandable access transmuscular approach with transforaminal interbody fusion (TLIF) for lumbar spinal stenosis is a minimally invasive approach to traditional open surgery. The surgical procedure can be divided into four steps: 1. After preoperative fluoroscopic localization of the surgical segment, an incision can be made at 25px adjacent to the median, and the paravertebral muscles can be propped up by applying dilators through the longest muscle and the multifidus interval to establish an expandable propped-up working channel, which is directly positioned at the surgical site. The bony landmarks and bone graft bed are located directly without extensive dissection of muscles and soft tissues, resulting in a short incision, less intraoperative bleeding, less inflammatory tissue reaction, and faster postoperative recovery. The postoperative spinal stability is maintained on the basis of preserving the muscles and ligaments as much as possible. 2.The cold light source is established on the channel, and the spinal cord and nerve decompression can be completed under direct vision in a clear operative field. 3.After dealing with the degenerated disc and bone graft bed, the channel can be adjusted through the connecting rod to complete the intervertebral bone graft fusion and arch nail implantation and fixation. 4.Take out the channel and close the incision layer by layer. There is less damage to the paravertebral muscles during the operation, and the muscles can close by themselves after the spacer is removed, leaving less dead space and blood accumulation after the operation, which can greatly reduce the incidence of poor healing and infection of the incision after the operation.