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Table 3 L4 and L5 spinous process parameters at baseline 1 week and 1 year after surgery

From: Bone resorption during the first year after implantation of a single-segment dynamic interspinous stabilization device and its risk factors

 

Bone resorption (n = 29)

Nobone resorption (n = 15)

p

L4 spinous process

Height

Baseline

83.0 ± 9.7

81.8 ± 8.7

.698

1 week

77.5 ± 9.3

76.6 ± 11.0

.776

1 year

71.2 ± 11.2

69.4 ± 11.9

.635

Significant resorptiona

5 (17.2)

0 (0.0)

.149

Length

Baseline

54.6 ± 7.4

57.2 ± 7.4

.279

1 week

50.5 ± 8.3

51.7 ± 8.0

.654

1 year

40.4 ± 10.1

46.7 ± 8.1

.042*

Significant resorptiona

17 (58.6)

0 (0.0)

.001*

Thickness

Baseline

13.2 ± 2.7

13.1 ± 2.2

.871

1 week

12.4 ± 2.6

12.1 ± 2.7

.725

1 year

11.1 ± 2.5

11.5 ± 2.7

.604

Significant resorptiona

7 (24.1)

0 (0.0)

.077

L5 spinous process

Height

Baseline

73.9 ± 11.2

70.3 ± 11.8

.319

1 week

67.6 ± 11.3

64.3 ± 10.9

.358

1 year

56.0 ± 11.5

57.4 ± 10.4

.699

Significant resorptiona

11 (37.9)

0 (0.0)

.008*

Length

Baseline

42.5 ± 10.6

46.1 ± 7.6

.244

1 week

37.3 ± 10.2

41.4 ± 6.6

.167

1 year

25.6 ± 6.9

37.2 ± 7.3

<.001*

Significant resorptiona

21 (72.4)

0 (0.0)

<.001*

Thickness

Baseline

12.6 ± 2.9

11.4 ± 2.7

.182

1 week

11.9 ± 2.8

10.3 ± 2.8

.094

1 year

10.0 ± 2.1

9.7 ± 2.9

.704

Significant resorptiona

12 (41.4)

0 (0.0)

.003*

  1. Data are presented as mean ± standard deviation or counts (percentage).
  2. *p < .05, indicates a significant difference between groups.
  3. aBone resorption rate = (value at 1 week postoperative – value at 1 year postoperative)/value at 1 year postoperative × 100. Significant resorption defined as a bone resorption rate > 20%.