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Table 2 Association between intradiscal vacuum phenomena (VPs) and disc degeneration

From: Morphology of intervertebral disc ruptures evaluated by vacuum phenomenon using multi-detector computed tomography: association with lumbar disc degeneration and canal stenosis

A: Shape MRI Pfirrmann’s classification of disc degeneration Total
I II III IV V
VP (−) Count
(% raw)
8
(3.0%)
55 *
(20.6%)
77 *
(28.8%)
99
(37.1%)
28 *
(10.5%)
267
Exp. Count 4.8 34.5 59.3 102.3 66.0  
Corrected
P-value
0.02 < 0.0001 < 0.0001 0.51 < 0.0001  
Spot Count(% raw) 0
(0%)
1
(2.6%)
13
(34.2%)
20
(52.6%)
4
(10.5%)
38
Exp. Count 0.7 4.9 8.4 14.6 9.4  
Corrected
P-value
0.38 0.05 0.06 0.06 0.03  
Linear Count
(% raw)
0
(0%)
1
(2.2%)
8
(17.8%)
16
(35.6%)
20 *
(44.4%)
45
Exp. Count 0.8 5.8 10.0 17.2 11.1  
Count
(% raw)
0.03 0.02 0.45 0.69 0.0012  
Island Count
(% raw)
0
(0%)
0 *
(0%)
0 *
(0%)
34
(37.4%)
57 *
(62.6%)
91
Exp. Count 1.7 11.8 20.2 34.9 22.5  
Corrected
P-value
0.15 < 0.0001 < 0.0001 0.83 < 0.0001  
B: Distribution MRI Pfirrmann’s classification of disc degeneration Total
I II III IV V
VP (−) Count
(% raw)
8
(3.0%)
55 #
(20.6%)
77 #
(28.8%)
99
(37.1%)
28 #
(10.5%)
267
Exp. Count 4.8 34.5 59.3 102.3 66.0  
Corrected
P-value
0.02 < 0.0001 < 0.0001 0.51 < 0.0001  
A-N Count
(% raw)
0
(0%)
2
(2.7%)
10
(13.5%)
26
(35.1%)
36 #
(48.6%)
74
Exp. Count 1.3 9.6 16.4 28.4 18.3  
Corrected
P-value
0.20 0.004 0.45 0.53 < 0.0001  
N Count
(% raw)
0
(0%)
0
(0%)
9
(16.4%)
28
(50.9%)
18
(32.7%)
55
Exp. Count 1.0 7.1 12.2 21.1 13.6  
Corrected
P-value
0.28 0.0023 0.26 0.04 0.14  
N-P Count
(% raw)
0
(0%)
0
(0%)
2
(7.1%)
11
(39.3%)
15 #
(53.6%)
28
Exp. Count 0.5 3.6 6.2 10.7 6.9  
Corrected
P-value
0.46 0.004 0.05 0.91 0.00025  
A-N-P Count
(% raw)
0
(0%)
0
(0%)
0
(0%)
5
(29.4%)
12 #
(70.6%)
17
  Exp. Count 0.3 2.2 3.8 6.5 4.2  
  Corrected
P-value
0.2 0.004 0.05 0.53 < 0.0001  
  1. The results of a contingency-table test are presented. A: VP shape analysis. B: VP distribution analysis. Percentages of the raw marginal total (% raw) are in parentheses. Exp. Count: expected count; VP (−): non-ruptured group; Nucleus pulposus: N; anterior annulus fibrosus: A; and posterior annulus fibrosus: P. *P < 0.0025, #P < 0.002 (by Bonferroni correction). The cells with counts above or below the expected count with statistical significance are shown in bold