Baseline demographics for groups A and B.
| Characteristic | Group A (n = 8) | Group B (n = 14) | P Value |
| Age, y, mean (SD) | 38.5 (3.2) | 32.6 (2.1) | 0.061 |
| Baseline ODI, mean (SD) | 57.5 (4.6) | 54.7 (3.6) | 0.388 |
| Baseline VAS back, mean (SD) | 7.1 (0.4) | 7.6 (0.4) | 0.404 |
| Baseline ANS, mean (SD) | 1.3 (0.4) | 1.3 (0.4) | 0.357 |
| Sex, M/F, n (%) | 5 (63%)/3 (38%) | 1 (7%)/13 (93%) | |
| Smoker, n (%) | 1 (12.5%) | 6 (43%) | |
| Level treated, n (%) | |||
| L4/5 | 4 (50%) | 9 (64%) | |
| L5/S1 | 4 (50%) | 5 (36%) |
ANS, analgesic score; ODI, Oswestry Disability Index; VAS, visual analog scale.