Fig. 3

A 61-year-old male was diagnosed with isthmic spondylolisthesis. He underwent posterior decompression, bone graft fusion and internal fixation in our hospital. Figures A and B show that the patient had spondylolisthesis of L4 (i°). The isthmus of the bilateral pedicle of the L4 vertebral body was not connected. Figures C and D show that the pedicle screws on both sides of the L4 vertebral body invaded the proximal articular process after the operation. According to the SEO grading method, the patient can be classified into grade 2, and the pedicle screws obviously break the ring joint. Figures E and F show the position of internal fixation after the operation. As shown in Figure G, the patient was reexamined 2 months after the operation, and the pedicle screws of both sides of L4 invaded the proximal articular process. According to the SEO grading method, the patient can be classified into two grades. Figures H and I show the position of internal fixation at 2 months after the operation