| Outcome measurement | Improvement from baseline to 2-year follow-up | ||
|---|---|---|---|
| Group B | Group A | p | |
| VAS back pain | 37 ± 28 | 32 ± 38 | 0.59 |
| ODI | 22 ± 17 | 20 ± 22 | 0.66 |
Mean improvement from baseline to 2-year follow-up as reported with the VAS and ODI instruments. Abbreviations: VAS = visual analogue scale; ODI = Oswestry disability index.