Comparison of degenerative lumbar spondylolisthesis and isthmic lumbar spondylolisthesis: effect of pedicle screw placement on proximal facet invasion in surgical treatment

Table 4 Statistical analysis of the two groups of patients with different degrees of proximal facet joint invasion

The grade of invasion of facet joint by a pedicle screw	Group A (Number of cases)	Group B (Number of cases)	P	Z
Grade 0	320	116	<0.001	-9.050
Grade 1	128	248
Grade 2	28	96

Note: The level and number of cases of pedicle screws in different degrees were compared between the two groups. P value <0.001.

ISSN: 1471-2474