Procedure-specific clinical variables associated with treatment outcome
| Clinical variable | Procedural failure (n=193) | Procedural success (n=139)* | P value |
| Epidural steroid injections | 90 | 73 | |
| Physical exam | |||
| Straight leg raising test (−) | 39 (43) | 32 (44) | 0.95 |
| Straight leg raising test (+) | 51 (57) | 41 (56) | |
| Pathology | |||
| Herniated disc | 42 (48) | 32 (45) | 0.13 |
| Spinal stenosis | 31 (35) | 28 (39) | |
| Herniated disc and spinal stenosis | 4 (5) | 8 (11) | |
| Spondylosis without compression | 11 (13) | 3 (4) | |
| Facet interventions | 68 | 33 | |
| <50% pain relief from diagnostic block | 36 (53) | 1 (3) | – |
| 50%–79% pain relief from diagnostic block | 23 (34) | 15 (45) | <0.001* |
| ≥80% pain relief from diagnostic block | 9 (13) | 17 (52) | <0.001† |
| Sacroiliac joint injection | 33 | 33 | |
| Physical exam | |||
| Gaenslen’s test (−) | 7 (21) | 10 (30) | 0.4 |
| Gaenslen’s test (+) | 26 (79) | 23 (70) | |
| Patrick’s test (−) | 9 (27) | 15 (45) | 0.12 |
| Patrick’s test (+) | 24 (73) | 18 (55) | |
| Positive Patrick’s & Gaenslen’s tests | 22 (67) | 15 (45) | 0.083 |
| Prior surgery | |||
| Prior back surgery | 7 (21) | 4 (13) | 0.35 |
| No prior back surgery | 26 (79) | 28 (88) | |
| <50% pain relief from diagnostic block | 15 (45) | 3 (9) | – |
| 50%–79% pain relief from diagnostic block | 9 (27) | 17 (52) | <0.001* |
| ≥80% pain relief from diagnostic block | 9 (27) | 13 (39) | 0.30† |
*Comparison of procedural failure versus success based on ≥50% vs. < 50% pain relief threshold as definition of positive block.
†Comparison of procedural failure versus success based on ≥80% vs. < 80% pain relief threshold as definition of positive block.