Table 3.

Final forward stepwise multiple linear regression model relating the best combination of clinical and imaging predictors to the DSSEP improvement upon extension and flexion

	Variables	Logit Coefficient B	Standard Error	P Value	Odds Ratio	Predicted Probability
DSSEP improvement upon Extension
Step 1	With straight or sigmoid alignment	2.927	1.115	0.009*	18.667	81.6%
	Constant	−3.332	1.018	0.001	0.036
Step 2	Stenotic segment number ≤ 2	2.508	1.174	0.033*	12.275	85.7%
	With straight or sigmoid alignment	2.754	1.165	0.018*	15.711
	Constant	−4.876	1.438	0.001	0.008
Step 3	Stenotic segment number ≤ 2	2.905	1.373	0.034*	18.272	85.7%
	With straight or sigmoid alignment	3.341	1.402	0.017*	28.253
	Disc degeneration grade ≤ 3	2.368	1.251	0.058	10.677
	Constant	−6.478	2.083	0.002	0.002
DSSEP improvement upon Flexion
Step 1	Mühle grade 3	1.754	0.762	0.021*	5.778	77.6%
	Constant	−2.159	0.61	0	0.115
Step 2	Disease duration ≤6 months	1.642	0.816	0.044*	5.165	85.7%
	Mühle grade 3	1.987	0.834	0.017*	7.295
	Constant	−2.914	0.804	0	0.054

* p < 0.05