Intention-to-treat analysis*
| Outcome | Lumbar fusion (N=61)† | Cognitive/exercises (N=50)† | Adjusted treatment effect (95% CI)‡ |
|---|---|---|---|
| Primary | |||
| Oswestry disability index† | |||
| Baseline | 44.1±10.7 | 43.4±11.1 | 1.1 (−5.9 to 8.2) |
| 4 Years | 29.7±20.5 | 27.0±19.4 | |
| Secondary | |||
| General function score† | |||
| Baseline | 37.3±19.3 | 40.0±18.9 | −3.5 (−11.6 to 4.6) |
| 4 Years | 25.8±24.7 | 21.4±21.5 | |
| Back pain† | |||
| Baseline | 62.8±14.5 | 64.2±12.5 | 2.3 (−6.4 to 10.9) |
| 4 Years | 42.2±23.9 | 44.7±22.8 | |
| Lower limb pain† | |||
| Baseline | 48.5±24.4 | 44.8±23.5 | 1.3 (−8.3 to 10.8) |
| 4 Years | 34.8±29.4 | 33.5±24.7 | |
| Emotional distress§ | |||
| Baseline | 1.9±0.5 | 1.9±0.5 | −0.1 (−0.1 to 0.3) |
| 4 Years | 1.7±0.6 | 1.7±0.6 | |
| Life satisfaction¶ | |||
| Baseline | 5.0±2.2 | 4.6±1.7 | −0.3 (−1.1 to 0.6) |
| 4 Years | 6.2±2.5 | 6.4±2.3 | |
| Fear-avoidance beliefs physical activity** | |||
| Baseline | 13.0±5.0 | 15.4±5.0 | −3.5 (−5.8 to −1.1) |
| 4 Years | 9.1±7.3 | 7.0±6.0 | |
| Fear-avoidance beliefs work** | |||
| Baseline | 26.1±10.5 | 28.4±10.7 | −4.3 (−8.3 to −0.2) |
| 4 Years | 23.9±13.8 | 21.1±12.5 | |
| Patients overall rating – no (%) success†† | |||
| 1 Year | 38 (62) | 32 (64) | 1.0 (0.8 to 1.5) |
| Work – no (%) | |||
| Baseline | 9 (15) | 8 (16) | 0.8 (0.3 to 1.9) |
| 1 Year | 16 (26) | 17 (34) | |
↵* Mean values±SD unless otherwise noted.
↵† The Oswestry disability index, the general function score, back and lower limb pain ranges from 0 to 100, with lower scores indicating fewer symptoms.
↵‡ The treatment effect is the difference between patients randomly assigned to lumbar fusion and cognitive intervention and exercises at 4 years with adjustments for baseline score, age, gender and previous disc surgery. All patients randomly assigned (n=124) are included with last observed value carried forward.
↵†† All who did not attend the 4-year follow-up are classified as non-success.
↵§ Emotional stress ranges from 1 to 4, with lower scores indicating less severe symptoms.
↵¶ Life satisfaction ranges from 1 to 10, with higher scores indicating better life satisfaction.
↵** Fear-avoidance beliefs for physical activity ranges from 0 to 24 and for work from 0 to 42, with lower scores indicating less strong beliefs for physical activity and work hurting the back.