Fig. 1

Li Moumou, a 63-year-old female, was diagnosed with degenerative lumbar spondylolisthesis and underwent posterior decompression, bone grafting, fusion and internal fixation at our hospital. A, B: L4 vertebral body spondylolisthesis (I°) before the operation. C: Preoperative CT showing lumbar degenerative changes and L4 spondylolisthesis (I°). D: Preoperative MRI showing L4 spondylolisthesis (I°), degeneration and bulging of L2-3, L3-4 and L4-5 intervertebral discs, and compression of the dural sac at the corresponding levels. E, F: X-ray showing the position of internal fixation of the lumbar spine 2 months after the operation. G: According to Herren’s grading method, the left screw showed no invasion of the proximal facet joint (grade 0); the right screw showed obvious entry of the articular cavity of the proximal facet joint (grade 2)