Table 1.

Instability measurements for the flexion and extension positions between the three postures

Variable	Standing			Sitting			Lateral decubitus
	Flexion	Extension	p-value	Flexion	Extension	p-vale	Flexion	Extension	p-value
Intervertebral angle (°)	5.8	8.5	<0.01	3.4	6.6	<0.01	3.7	9.1	<0.01
Slippage (%)	17.1	15.1	0.07	17.4	18.0	0.88	18.0	13.0	<0.01
Intervertebral disc area ratio (mm2)	29.6	32.6	<0.01	30.0	31.7	0.10	30.5	34.1	<0.01