Table 2 Diagnostic value of clinical examination variables in relation to single anaesthetic zygapophysial joint block
From: Zygapophysial joint blocks in chronic low back pain: a test of Revel's model as a screening test
Reference Standard A (75% reduction in Pain VAS) | ||||
|---|---|---|---|---|
N = 116 1 | Contingency table | |||
Injection result | ||||
Positive | Negative | |||
Criteria satisfied | 3 | 8 | ||
Criteria not satisfied | 24 | 81 | ||
% Sn 3 (95 CI8) | % Sp 4 (95 CI) | % PPV 5 (95 CI) | % NPV 6 (95 CI) | + LR 7 (95 CI) |
11.1 (3.9,28.1) | 91.0 (83.3,95.4) | 27.3 (9.8,56.6) | 77.1 (68.2,84.1) | 1.2 (0.3,4.3) |
Reference Standard B (Abolition of Primary Pain) | ||||
N = 111 2 | Contingency table | |||
Injection result | ||||
Positive | Negative | |||
Criteria satisfied | 3 | 6 | ||
Criteria not satisfied | 15 | 84 | ||
% Sn (95 CI) | % Sp (95 CI) | % PPV (95 CI) | % NPV (95 CI) | + LR (95 CI) |
16.7 (5.8,39.2) | 93.3 (86.2,96.9) | 33.3 (12.1,64.6) | 84.9 (76.5,90.6) | 2.5 (0.7,9.1) |