Table 2 Comparison between computerized tomographic parameters and ASIA classification

AO classification

22

58 %

8

47 %

4

29 %

4

27 %

4

19.0 %

Transverse canal diameter

25.48

(22.65, 27.63)

26.54

(23.84, 28.16)

26.24

(23.44, 28.22)

24.19

(20.64, 28.82)

22.68

(0.01, 27.65)

Median sagittal diameter

9.76

(7.47, 13.94)

11.02

(7.29, 15.27)

12.03

(7.25, 14.01)

8.95

(6.17, 11.66)

6.27

(0.01, 8.76)

Compression ratio of median sagittal diameter

0.365

(0.07, 0.502)

0.308

(0.031, 0.504)

0.367

(0.084, 0.574)

0.476

(0.288, 0.788)

0.600

(0.434, 1.000)

Compression ratio of canal cross-sectional area

0.256

(0.045, 0.435)

0.274

(0.082, 0.445)

0.171

(0.046, 0.565)

0.218

(0.106, 0.44)

0.386

(0.246, 0.839)

Compression ratios of AVH

0.146

(0.107, 0.294)

0.190

(0.138, 0.276)

0.259

(0.147, 0.309)

0.386

(0.254, 0.47)

0.363

(0.256, 0.454)

Compression ratios of MVH

0.104

(0.068, 0.185)

0.097

(0.056, 0.17)

0.158

(0.078, 0.225)

0.199

(0.075, 0.277)

0.248

(0.105, 0.343)

Compression ratios of PVH

0.191

(0.112, 0.281)

0.181

(0.107, 0.247)

0.259

(0.189, 0.341)

0.276

(0.119, 0.387)

0.286

(0.181, 0.392)

The distance of posterior margin with upper vertebra

4.95

(4.31, 6.12)

5.02

(3.64, 5.92)

4.76

(3.51, 5.86)

5.08

(4.02, 6.49)

4.65

(3.97, 5.15)

The distance of posterior margin with below vertebra

3.98

(3.27, 4.66)

4.29

(3.25, 5.24)

3.86

(3.21, 4.64)

3.59

(2.76, 4.23)

3.66

(3.36, 4.89)

Cobb angle

10.3

(8.6, 14.0)

11.3

(2.9, 21.0)

10.7

(7.1, 17.9)

12.9

(10, 18.7)

16.2

(9.4, 22.8)

Flip angle

16.44

(10.24, 31.59)

15.90

(7.92, 28.3)

32.26

(15.47, 43.6)

28.26

(10.9, 42.31)

21.61

(10.54, 37.64)

Rotation angle

0.10

(0.1, 4.75)

2.95

(0.1, 3.94)

3.21

(0.1, 5.8)

4.30

(1.96, 5.63)

2.52

(0.1, 5.46)