Table 1: Mean Intervertebral Space Ratio (IVS) ± Standard Deviation for LPDSS and Rigidly Stabilized Groups

Group	Preoperative	Postoperative (3 Months)	Postoperative (12 Months)	Postoperative (24 Months)
LPDSS	0.298 ± 0.067	0.322 ± 0.065	0.296 ± 0.065	0.298 ± 0.061
Rigid	0.342 ± 0.051	0.340 ± 0.031	0.325 ± 0.048	0.322 ± 0.056
p-value (LPDSS vs Rigid)	0.030	0.472	0.307	0.209