Table 2. Effect of Spinal Cord Burst Stimulation on Primary and Secondary Outcomes.
| Mean score (95% CI) | P value | ||||
|---|---|---|---|---|---|
| At baseline | Spinal cord burst stimulation | Placebo stimulation | Between-group difference | ||
| No. of stimulation periods | 91 | 89 | |||
| Primary outcome | |||||
| Oswestry Disability Index, pointsa | 44.7 (41.4 to 47.9) | 34.0 (30.0 to 38.1) | 35.4 (31.3 to 39.4) | ||
| Change from baseline | −10.6 (−14.1 to −7.2) | −9.3 (−12.7 to −5.9) | −1.3 (−3.9 to 1.3) | .32 | |
| Secondary outcomes | |||||
| Numerical Rating Scaleb | |||||
| Leg pain | 7.3 (6.8 to 7.7) | 5.9 (5.3 to 6.4) | 6.1 (5.6 to 6.6) | −0.2 (−0.7 to 0.2) | .32 |
| Back pain | 6.8 (6.4 to 7.3) | 5.7 (5.2 to 6.2) | 6.1 (5.6 to 6.6) | −0.4 (−0.8 to 0.04) | .07 |
| 5-Dimension EuroQol indexc | 0.21 (0.13 to 0.28) | 0.48 (0.39 to 0.56) | 0.44 (0.35 to 0.53) | 0.04 (−0.03 to 0.11) | .32 |
| Physical activity leveld | |||||
| No. of steps per day | 6775 (5651 to 7899) | 7561 (6411 to 8710) | 7155 (6006 to 8305) | 405 (−422 to 1233) | .34 |
| Time spent standing or walking, h/d | 3.8 (3.3 to 4.3) | 4.0 (3.5 to 4.4) | 4.0 (3.6 to 4.4) | −0.02 (−0.4 to 0.3) | .89 |
a
Scores range from 0 points (no disability) to 100 points (maximum disability). The minimal clinically important difference (MCID) was 10 points. A typical patient with moderate back pain and disability would have a score between 20 and 40. Scores greater than 40 indicate severe disability.
b
Scores range from 0 (no pain) to 10 (worst pain imaginable). The MCID was 1.0 points.
c
A score of 0 indicates death and a score of 1 indicates a perfect health state. The MCID was 0.03. Scores between 0.2 and 0.5 represented a severe to moderate reduction in overall health-related quality of life.
d
Measured using a body-worn accelerometer (ActivPAL, PAL Technologies, Ltd).