Table 3 Preoperative and postoperative radiographic parameters between the P-A and A-P groups

Number of patients

178

82

C7 SVA

Preoperative

212.5 ± 195.3

184.9 ± 178.2

0.278

Postoperative

15.2 ± 35.3

38.8 ± 58.4

 < 0.001

Change

-197.4 ± 178.3

-146.1 ± 135.5

0.021

TK

Preoperative

11.6 ± 10.7

13.1 ± 12.6

0.333

Postoperative

27.8 ± 18.3

28.9 ± 15.8

0.663

Change

16.3 ± 5.5

15.8 ± 6.2

0.556

TLK

Preoperative

32.7 ± 21.5

29.4 ± 17.4

0.228

Postoperative

14.9 ± 6.6

16.2 ± 9.3

0.188

Change

-17.8 ± 15.7

-13.2 ± 13.5

0.023

PI

Preoperative

60.0 ± 10.8

61.7 ± 14.0

0.283

PT

Preoperative

38.4 ± 17.4

34.9 ± 14.3

0.106

Postoperative

21.0 ± 4.2

20.3 ± 8.7

0.390

Change

-17.4 ± 18.0

-14.6 ± 10.2

0.177

LL

Preoperative

-3.5 ± 5.7

-4.0 ± 5.4

0.523

Postoperative

-57.2 ± 25.8

-48.3 ± 12.8

0.004

Change

-53.7 ± 32.5

-44.3 ± 19.8

 < 0.001

PI − LL

Preoperative

56.5 ± 31.2

57.7 ± 27.9

0.761

Postoperative

2.9 ± 5.5

13.4 ± 8.4

 < 0.001

Number of patients

6

5

SL L1/2

Preoperative

1.5 ± 0.8

1.5 ± 0.8

0.919

Postoperative

-3.4 ± 1.4

-3.5 ± 1.5

0.937

Change

-4.9 ± 1.7

-5.0 ± 1.9

0.929

Number of patients

150

75

SL L2/3

Preoperative

1.3 ± 0.3

1.4 ± 0.3

0.127

Postoperative

-14.9 ± 6.2

-13.0 ± 7.2

0.041

Change

-16.2 ± 5.8

-14.4 ± 7.1

0.043

Number of patients

162

78

SL L3/4

Preoperative

1.6 ± 0.7

1.5 ± 0.2

0.151

Postoperative

-14.6 ± 5.2

-12.3 ± 6.4

0.003

Change

-16.2 ± 5.8

-13.8 ± 6.6

0.004

Number of patients

169

79

SL L4/5

Preoperative

-1.9 ± 0.9

-2.1 ± 1.3

0.187

Postoperative

-16.9 ± 7.3

-13.4 ± 6.6

 < 0.001

Change

-15.0 ± 8.5

-11.3 ± 8.2

0.001