Baseline demographic and clinical characteristics of study subjects
| Characteristic | Facet interventions (n=112) | Sacroiliac joint injections (n=67) | Epidural steroid injection (n=167) | Total cohort (n=346) | P Value* |
| Age, years (mean±SD) | 51±14 | 53±16 | 52±14 | 52±14 | 0.68 |
| Sex, n (%) | 0.091 | ||||
| Female | 53 (47.3) | 43 (64.2) | 89 (53.3) | 161 (46.5) | |
| Male | 59 (52.7) | 24 (35.8) | 78 (46.7) | 185 (53.5) | |
| Duration of pain, years (mean±SD) | 7±7 | 5±6 | 5±7 | 6±7 | 0.057 |
| Obesity, n (%) | 54 (48.2) | 27 (40.3) | 74 (44.3) | 155 (44.8) | 0.58 |
| Smoking, n (%) | 24 (21.4) | 10 (14.9) | 47 (28.1) | 81 (23.4) | 0.081 |
| Bilateral symptoms, n (%) | 66 (60.0) | 25 (37.9) | 59 (35.3) | 150 (43.7) | <0.001 |
| Inciting event, n (%) | 41 (36.6) | 31 (46.3) | 52 (31.1) | 124 (35.8) | 0.091 |
| Opioid use, n (%) | 21 (18.8) | 13 (19.4) | 30 (18.0) | 64 (18.5) | 0.96 |
| Non-opioid medication use† | |||||
| Any non-opioid | 83 (74.1) | 47 (70.1) | 131 (78.4) | 261 (75.4) | 0.38 |
| Neuropathic adjuvant | 26 (23.2) | 14 (20.9) | 61 (36.5) | 101 (29.2) | 0.014 |
| Non-steroidal anti-inflammatory Drug | 54 (48.2) | 34 (50.7) | 87 (52.1) | 175 (50.6) | 0.82 |
| Muscle relaxant | 22 (19.6) | 7 (10.4) | 30 (18.0) | 59 (17.1) | 0.26 |
| Other non-opioid analgesic | 10 (8.9) | 3 (4.5) | 17 (10.2) | 30 (8.7) | 0.37 |
| Tramadol | 16 (14.3) | 7 (10.4) | 26 (15.6) | 49 (14.2) | 0.6 |
| Active duty, n (%) | 27 (24.1) | 14 (20.9) | 15 (9.6) | 57 (16.5) | 0.013 |
| Disability, worker’s compensation or medical board, n (%)‡ | 25 (22.9) | 16 (24.6) | 48 (29.6) | 89 (26.5) | 0.44 |
| Coexisting chronic pain condition, n (%)§ | |||||
| Any pain condition | 82 (73.2) | 37 (55.2) | 91 (54.5) | 210 (60.7) | 0.004 |
| Neck pain | 21 (18.8) | 11 (16.4) | 25 (15.0) | 57 (16.5) | 0.71 |
| Headache | 11 (9.8) | 6 (9.0) | 11 (6.6) | 28 (8.1) | 0.6 |
| Arthralgia | 55 (49.1) | 23 (34.3) | 48 (28.7) | 126 (36.4) | 0.002 |
| Neuropathy | 10 (8.9) | 8 (11.9) | 17 (10.2) | 35 (10.1) | 0.81 |
| Abdominal/pelvic pain | 1 (0.9) | 4 (6.0) | 3 (1.8) | 8 (2.3) | 0.076 |
| Fibromyalgia | 1 (0.9) | 2 (3.0) | 11 (6.6) | 14 (4.0) | 0.054 |
| Other chronic pain | 9 (8.0) | 6 (9.0) | 12 (7.2) | 27 (7.8) | 0.9 |
| Multiple pain conditions | 13 (11.6) | 9 (13.4) | 22 (13.2) | 44 (12.7) | 0.91 |
| Coexisting psychiatric condition, n (%)¶ | |||||
| Any psychiatric condition | 49 (43.8) | 27 (40.3) | 75 (44.9) | 151 (43.6) | 0.81 |
| Anxiety | 22 (19.6) | 14 (20.9) | 38 (22.8) | 74 (21.4) | 0.82 |
| Depression | 25 (22.3) | 13 (19.4) | 44 (26.3) | 82 (23.7) | 0.48 |
| Post-traumatic stress | 4 (3.6) | 3 (4.5) | 7 (4.2) | 14 (4.0) | 0.95 |
| Substance abuse history | 7 (6.3) | 5 (7.5) | 18 (10.9) | 30 (8.7) | 0.37 |
| Other | 5 (4.5) | 3 (4.5) | 8 (4.8) | 16 (4.6) | 0.99 |
| Multiple | 15 (13.4) | 5 (7.5) | 26 (15.6) | 46 (13.3) | 0.26 |
| Non-organic signs (mean±SD)** | 0.5±1.0 | 0.6±1.2 | 0.9±1.3 | 0.7±1.2 | 0.035 |
| Expectations (mean±SD)†† | 3.6±1.3 | 3.9±1.4 | 4.0±1.3 | 3.9±1.3 | 0.047 |
| Athens Insomnia Scale (mean±SD) | 9±5 | 9±6 | 10±6 | 9±5 | 0.28 |
| Quick Inventory of Depressive Symptomatology (QIDS; mean±SD) | 11±7 | 11±9 | 12±8 | 12±8 | 0.46 |
| Oswestry Disability Score (mean±SD) | 36±15 | 37±17 | 41±17 | 39±16 | 0.030 |
| Procedure-related pain (mean±SD) | |||||
| Skin wheal | 4.7±2.6 | 4.7±2.6 | 3.9±2.7 | 4.3±2.7 | 0.019 |
| Procedure | 5.5±2.7 | 6.4±2.7 | 4.9±3.0 | 5.4±2.9 | 0.001 |
| Average NRS back pain score (mean±SD) | 6.0±1.6 | 6.2±1.8 | 5.9±2.3 | 6.0±2.0 | 0.46 |
| Worst NRS back pain score (mean±SD) | 8.7±1.3 | 8.6±1.4 | 8.3±2.5 | 8.5±1.9 | 0.23 |
| Average NRS leg pain score (mean±SD) | 5.9±2.0 | ||||
| Worst NRS leg pain score (mean±SD) | 8.5±1.6 | ||||
*Based on one-way ANOVA for continuous variables and χ2 test for categorical variables.
†Neuropathic adjuvant includes anticonvulsants and antidepressants. Non-steroidal anti-inflammatory drug also includes acetaminophen. Other non-opioid analgesic includes topical agents such as lidocaine and capsaicin.
‡Military equivalent of civilian disability.
§Denotes active condition (ie, being treated); other includes postsurgical pain, plantar fasciitis, post-stroke pain and pain secondary to systemic disease (eg, lupus and sickle cell anemia).
¶Denotes active condition (ie, being treated) except for substance abuse (ongoing recovery); other includes somatic symptom disorder, personality disorder, etc.
**Non-organic signs based on five categories of Waddell signs.
††Expectations based on 6-point Likert scale (1=don’t expect any relief, 6=would only be satisfied with complete pain relief and restoration of function).
ANOVA, analysis of variance; NRS, numerical rating scale.