Patient demographics and unadjusted comparisons
| All | Non-ESPB | ESPB | P value*† | |
| Sample size (n) | 370 | 200 | 170 | |
| Sociodemographic characteristics | ||||
| Median age (IQR) in years | 62.00 (15.00–84.00) | 61.00 (15.00–83.00) | 64.50 (17.00–84.00) | 0.01 |
| Sex n (%) | ||||
| Male | 188 (50.8) | 104 (52.0) | 84 (49.4) | 0.68 |
| Female | 182 (49.2) | 96 (48.0) | 86 (50.6) | |
| Race and ethnicity n (%) | ||||
| Non-Hispanic white | 314 (84.9) | 176 (88.0) | 138 (81.2) | 0.05 |
| Non-Hispanic black | 30 (8.1) | 16 (8.0) | 14 (8.2) | |
| Other or mixed | 26 (7.0) | 8 (4.0) | 18 (10.6) | |
| Current smoking n (%) | 33 (8.9) | 14 (7.0) | 19 (11.2) | 0.20 |
| History of anxiety n (%) | 47 (12.7) | 30 (15.0) | 17 (10.0) | 0.16 |
| History of depression n (%) | 35 (9.5) | 19 (9.5) | 16 (9.4) | 1.00 |
| History of chronic pain n (%) | 1 (0.3) | 1 (0.5) | 0 (0.0) | 1.00 |
| Preoperative opioid use n (%) | ||||
| All | 37 (10.0) | 21 (10.5) | 16 (9.4) | 0.86 |
| Oxycodone | 17 (4.6) | 11 (5.5) | 6 (3.5) | 0.46 |
| Tramadol | 15 (4.1) | 5 (2.5) | 10 (5.9) | 0.12 |
| Hydrocodone | 6 (1.6) | 3 (1.5) | 3 (1.8) | 1.00 |
| Hydromorphone | 2 (0.5) | 1 (0.5) | 1 (0.6) | 1.00 |
| Buprenorphine | 1 (0.3) | 0 (0.0) | 1 (0.6) | 0.46 |
| Oxymorphone | 1 (0.3) | 0 (0.0) | 1 (0.6) | 0.46 |
| Morphine | 1 (0.3) | 0 (0.0) | 1 (0.6) | 0.46 |
| Codeine | 1 (0.3) | 0 (0.0) | 1 (0.6) | 0.46 |
| Median MED (IQR) in mg | 20.00 (2.00–120.00) | 20.00 (2.00–60.00) | 17.50 (10.00–120.00) | 0.58 |
| Preoperative gabapentin or pregabalin use, n (%) | 78 (21.1) | 45 (22.5) | 33 (19.4) | 0.52 |
| Surgical characteristics | ||||
| Diagnosis n (%) | ||||
| DDD | 140 (37.8) | 83 (41.5) | 57 (33.5) | 0.13 |
| HNP | 71 (19.2) | 42 (21.0) | 29 (17.1) | 0.36 |
| Stenosis | 297 (80.3) | 149 (74.5) | 148 (87.1) | 0.00 |
| Spondylolisthesis | 266 (71.9) | 140 (70.0) | 126 (74.1) | 0.42 |
| Scoliosis | 29 (7.8) | 16 (8.0) | 13 (7.6) | 1.00 |
| Surgical level n (%) | ||||
| T12–L1 | 4 (1.1) | 2 (1.0) | 2 (1.2) | 1.00 |
| L1–L2 | 2 (0.5) | 0 (0.0) | 2 (1.2) | 0.21 |
| L2–L3 | 21 (5.7) | 4 (2.0) | 17 (10.0) | 0.00 |
| L3–L4 | 70 (18.9) | 29 (14.5) | 41 (24.1) | 0.02 |
| L4–L5 | 274 (74.1) | 138 (69.0) | 136 (80.0) | 0.02 |
| L5–S1 | 174 (47.0) | 102 (51.0) | 72 (42.4) | 0.12 |
| Levels fused n (%) | ||||
| 1 level | 261 (70.5) | 142 (71.0) | 119 (70.0) | 0.91 |
| 2 levels | 109 (29.5) | 58 (29.0) | 51 (30.0) | |
| Levels decompressed n (%) | ||||
| 1 level | 225 (60.8) | 132 (66.0) | 93 (54.7) | 0.06 |
| 2 levles | 117 (31.6) | 58 (29.0) | 59 (34.7) | |
| 3 levels | 20 (5.4) | 7 (3.5) | 13 (7.6) | |
| 4 levels | 7 (1.9) | 2 (1.0) | 5 (2.9) | |
| Unknown | 1 (0.3) | 1 (0.5) | 0 (0.0) | |
| Median surgical duration (IQR) in mins | 174.0 (49.0–463.0) | 176.0 (61.0–380.0) | 171.5 (49.0–463.0) | 0.87 |
| ASA classification n (%) | ||||
| I | 23 (6.2) | 12 (6.0) | 11 (6.5) | 0.22 |
| II | 315 (85.1) | 166 (83.0) | 149 (87.6) | |
| III | 32 (8.6) | 22 (11.0) | 10 (5.9) | |
| Median BMI (IQR) kg/m2 | 27.90 (17.70–57.20) | 27.40 (17.70–57.20) | 28.70 (19.10–44.20) | 0.05 |
*P value compares outcomes in non-erector spinae plane block versus erector spinae plane block.
†Mann-Whitney U test was used to compare continuous variables and Fisher’s exact tests for categorical variables.
ASA, American Society of Anesthesiologists; BMI, body mass index; DDD, degenerative disc disease; ESPB, erector spinae plane block; HNP, herniated nucleus pulposus; L, lumbar vertebral level; MED, morphine equivalent dose; S, sacral level; T, thoracic vertebral level.