TABLE 2.
Summary of Back, Leg, and Overall Pain Visual Analogue Scale Scores Over Time for Permanently Implanted Patients
| Baseline | 3‐Month | 12‐Month | 24‐Month | |
|---|---|---|---|---|
| Back pain | ||||
| N | 46 | 41 | 39 | 34 |
| Mean raw VAS score, mm (SD) | 81.3 (9.5) | 24.9 (22.1) | 22.7 (25.7) | 18.6 (25.9) |
| Mean percent improvement in VAS scores (SD) | — | 69.2 (27.6) | 72.0 (31.0) | 77.3 (30.6) |
| Mean improvement in VAS scores, mm (SD, P value) | — | 56.7 (23.6, P < 0.001) | 57.9 (26.1, P < 0.001) | 62.5 (26.5, P < 0.001) |
| Responders (≥ 50% pain reduction) % | — | 75.6 | 76.9 | 85.3 |
| High responders (≥ 80% reduction) % | — | 53.7 | 56.4 | 67.6 |
| Leg pain | ||||
| N | 35 | 32 | 29 | 26 |
| Mean raw VAS score, mm (SD) | 77.7 (10.8) | 18.6 (19.0) | 21.1 (25.1) | 15.8 (22.0) |
| Mean percent improvement in VAS scores (SD) | — | 75.7 (24.3) | 72.1 (33.0) | 79.0 (30.3) |
| Mean improvement in VAS scores, mm (SD, P value) | — | 59.6 (22.0, P < 0.001) | 56.6 (27.6, P < 0.001) | 63.0 (26.0, P < 0.001) |
| Responders (≥ 50% pain reduction) % | — | 87.5 | 79.3 | 88.5 |
| High responders (≥ 80% reduction) % | — | 53.1 | 58.6 | 65.4 |
| Overall pain | ||||
| N | 50 | 45 | 43 | 38 |
| Mean raw VAS score, mm (SD) | 81.3 (11.2) | 22.8 (19.2) | 21.0 (22.3) | 15.3 (20.6) |
| Mean percent improvement in VAS scores (SD) | — | 71.2 (27.0) | 73.6 (28.0) | 81.2 (24.0) |
| Mean improvement in VAS scores, mm (SD, P value) | — | 58.6 (22.3, P < 0.001) | 59.8 (24.7, P < 0.001) | 66.1 (22.7, P < 0.001) |
| Responders (≥ 50% pain reduction) % | — | 80.0 | 81.4 | 89.5 |
| High responders (≥ 80% reduction) % | — | 42.2 | 53.5 | 68.4 |
P values resulting from paired t‐test that the mean change from baseline was significantly different from 0 with an alpha of 0.05.
Abbreviations: FBSS, failed back surgery syndrome; SCS, spinal cord stimulation; SD, standard deviation; VAS, visual analogue scale.