Table 2.

Radiographic changes of disc height on plain radiographs

	Pre-operation	Post-operation	t value	p value
DH (L4/5)	14.17 ± 1.74	14.01 ± 2.23	0.760	0.451
DHI (L4/5)	0.381 ± 0.03	0.370 ± 0.04	1.993	0.051
DH (L5S1)	14.13 ± 1.90	13.82 ± 2.03	1.712	0.093
DHI (L5S1)	0.389 ± 0.05	0.380 ± 0.05	1.772	0.082

DH, disc height; DHI, disc height index