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

 Step 1

With straight or sigmoid alignment

2.927

1.115

0.009*

18.667

Constant

−3.332

1.018

0.001

0.036

 Step 2

Stenotic segment number ≤ 2

2.508

1.174

0.033*

12.275

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

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

 Step 1

Mühle grade 3

1.754

0.762

0.021*

5.778

Constant

−2.159

0.61

0

0.115

 Step 2

Disease duration ≤6 months

1.642

0.816

0.044*

5.165

Mühle grade 3

1.987

0.834

0.017*

7.295

Constant

−2.914

0.804

0

0.054