Demographic and clinical factors associated with treatment outcome
| Variable | Procedural failure (n=193) | Procedural success (n=139)† | P value* |
| Procedure (n, % of procedure type) | 0.058§ | ||
| Facet interventions‡ | 68 (67.3) | 33 (32.7) | |
| Radiofrequency ablation | 29/58 (50) | 29/58 (50) | |
| Sacroiliac joint injection | 33 (50) | 33 (50) | |
| ESI | 92 (55.8) | 73 (44.2) | |
| Transforaminal | 38/79 (48.1) | 41/79 (51.9) | |
| Interlaminar | 53/85 (62.4) | 32/85 (37.6) | |
| Age, years (mean±SD) | 50±13 | 54±16 | 0.019 |
| Sex, n (%) | 0.38 | ||
| Female | 108 (60.3) | 71 (39.7) | |
| Male | 85 (55.6) | 68 (44.4) | |
| Duration of pain, years (mean±SD) | 6.7±7.7 | 4.7±5.7 | 0.01 |
| Obesity, n (%) | 97 (64.2) | 54 (35.8) | 0.039 |
| Bilateral symptoms, n (%) | 86 (61.9) | 53 (38.1) | 0.039 |
| Smoking, n (%) | 59 (75.6) | 19 (24.4) | <0.001 |
| Inciting event, n (%) | 76 (63.3) | 44 (36.7) | 0.15 |
| Opioid use, n (%) | 42 (65.6) | 22 (34.4) | 0.18 |
| Non-opioid use, n (%)¶ | |||
| Any adjuvant | 138 (55.2) | 112 (44.8) | 0.059 |
| Neuropathic adjuvant | 61 (63.5) | 35 (36.5) | 0.2 |
| Non-steroidal anti-inflammatory drug | 87 (51.5) | 82 (48.5) | 0.012 |
| Muscle relaxant | 29 (49.2) | 30 (50.8) | 0.12 |
| Other non-opioid analgesic | 15 (51.7) | 14 (48.3) | 0.46 |
| Tramadol | 32 (66.7) | 16 (33.3) | 0.2 |
| Active duty, n (%) | 31 (57.4) | 23 (42.6) | 0.12 |
| Disability, worker’s compensation or medical board, n (%)** | 61 (70.1) | 26 (29.9) | 0.009 |
| Coexisting chronic pain conditions, n (%)†† | |||
| Any pain condition | 122 (60.4) | 80 (39.6) | 0.3 |
| Neck pain | 32 (58.2) | 23 (41.8) | 0.99 |
| Headache | 17 (63.0) | 10 (37.0) | 0.6 |
| Arthralgia | 73 (59.8) | 49 (40.2) | 0.63 |
| Neuropathy | 19 (55.9) | 15 (44.1) | 0.78 |
| Abdominal/pelvic pain | 7 (87.5) | 1 (12.5) | 0.088 |
| Fibromyalgia | 8 (57.1) | 6 (42.9) | 0.94 |
| Other chronic pain‡‡ | 20 (80.0) | 5 (20.0) | 0.021 |
| Multiple pain conditions | 28 (65.1) | 15 (34.9) | 0.32 |
| Coexisting psychiatric condition, n (%)§§ | |||
| Any psychiatric condition | 96 (66.2) | 49 (33.8) | 0.009 |
| Anxiety | 47 (65.3) | 25 (34.7) | 0.16 |
| Depression | 56 (70.9) | 23 (29.1) | 0.008 |
| Posttraumatic stress disorder | 11 (78.6) | 3 (21.4) | 0.11 |
| Substance abuse | 22 (75.9) | 7 (24.1) | 0.043 |
| Other | 12 (75.0) | 4 (25.0) | 0.16 |
| Multiple psychiatric conditions | 33 (71.7) | 13 (28.3) | 0.044 |
| Non-organic signs (mean, SD)¶¶ | 0.9±1.3 | 0.5±1.0 | 0.004 |
| Expectations (mean±SD)*** | 3.9±1.3 | 3.8±1.3 | 0.31 |
| Athens Insomnia Scale (mean±SD) | 10±5 | 8±5 | <0.001 |
| Quick Inventory of Depressive Symptomatology (QIDS; mean±SD) | 13±8 | 9±7 | <0.001 |
| Oswestry Disability Score (mean±SD) | 42±17 | 35±15 | <0.001 |
| Procedure-related pain (mean, SD | |||
| Skin wheal | 4.5±2.7 | 4.1±2.7 | 0.21 |
| Procedure | 5.9±3.0 | 4.6±2.6 | <0.001 |
| Average baseline back pain score (mean±SD) | 6.3±2.0 | 5.6±2.0 | 0.002 |
| Worst baseline back pain score (mean±SD) | 8.8±1.7 | 8.1±2.2 | 0.001 |
| Average baseline leg pain score (mean±SD)††† | 6.2±2.0 | 5.4±1.8 | 0.006 |
| Worst baseline leg pain score (mean±SD)††† | 8.8±1.6 | 8.1±1.6 | 0.005 |
*Based on t-test for continuous variables and χ2 test for categorical variables.
†Procedural success defined as ≥2-point decrease in baseline average low back or leg pain score at 1 month after sacroiliac joint and epidural steroid injections, respectively, or low back pain score 3 months after radiofrequency ablation (or medical branch blocks for patients with sustained relief) for lumbar facet joint pain, coupled with >3/5 score on a Likert satisfaction scale.
‡Negative facet interventions include negative RFA outcome and negative facet blocks in patients who did not obtain long-term relief (n=1).
§Comparison among procedural success for facet RFA at 3 months, SIJ injection at 1 month, and ESI at 1 month.
¶Neuropathic adjuvants include anticonvulsants and antidepressants. Non-steroidal anti-inflammatory drugs include acetaminophen. Other non-opioid analgesics include topical agents such as lidocaine and capsaicin.
**Military equivalent of civilian disability.
††Denotes active condition (ie, being treated).
‡‡Other pain conditions include plantar fasciitis, central pain, persistent postsurgical pain and atypical chest pain.
§§Denotes active condition (ie, being treated) except for substance abuse.
¶¶Non-organic signs based on five categories of Waddell signs.
***Expectations based on a 6-point Likert scale.
†††Leg pain score only recorded for ESIs.
ESI, epidural steroid injection; RFA, radiofrequency ablation.