Table 2.

Comparison of pre-operative and post-operative radiographic parameters

	Pre-operative	Post-operative (≥ 6 months)	Percent increase	p value*
Static device (mean ± SD)
Disc height (mm)	9.0 ± 1.9	11.2 ± 1.8	24.4%	< 0.001
Foraminal height (mm)	20.0 ± 3.1	21.6 ± 3.0	8.0%	< 0.001
Lumbar lordosis (°)	58.0 ± 11.5	60.4 ± 12.8	4.1%	0.021
Segmental lordosis (°)	18.1 ± 5.4	19.1 ± 5.5	5.5%	0.054
Expandable device (mean ± SD)
Disc height (mm)	9.5 ± 2.1	13.7 ± 2.3	44.2%	< 0.001
Foraminal height (mm)	19.8 ± 2.6	23.6 ± 2.8	19.2%	< 0.001
Lumbar lordosis (°)	52.4 ± 10.5	54.9 ± 10.5	4.8%	0.008
Segmental lordosis (°)	19.0 ± 6.0	20.0 ± 5.7	5.3%	0.048

SD, standard deviation

Italic indicates statistical significance

*p values calculated using paired Student’s t tests