TABLE II.
Time-Weighted Average of Treatment Effects at Four Years According to Whether the Patient Had Neurogenic Claudication or Any Neurological Deficit
| Mean Change in Score Compared with Baseline* (Standard Error)
|
Treatment Effect (95% Confidence Interval) | ||
|---|---|---|---|
| Op. Group | Nonop. Group | ||
| SF-36 bodily pain score | |||
| Neurogenic claudication | 31.3 (0.9) | 12.9 (1.1) | 18.4 (16 to 20.8) |
| No neurogenic claudication | 29.7 (2.2) | 19.2 (2.4) | 10.4 (5.2 to 15.7) |
| P value | 0.51 | 0.015 | 0.006 |
| SF-36 physical function score | |||
| Neurogenic claudication | 25.3 (0.9) | 8.3 (1) | 17 (14.7 to 19.3) |
| No neurogenic claudication | 24.3 (2.2) | 12.8 (2.4) | 11.5 (6.5 to 16.6) |
| P value | 0.67 | 0.083 | 0.047 |
| Oswestry Disability Index | |||
| Neurogenic claudication | −23 (0.7) | −7.4 (0.8) | −15.6 (−17.4 to −13.8) |
| No neurogenic claudication | −20.6 (1.7) | −11.8 (1.9) | −8.8 (−12.8 to −4.9) |
| P value | 0.20 | 0.035 | 0.002 |
| SF-36 bodily pain score | |||
| Any neurological deficit | 31.8 (1.2) | 13.7 (1.4) | 18 (15.1 to 21) |
| No neurological deficit | 30.1 (1.3) | 14.3 (1.5) | 15.8 (12.7 to 19) |
| P value | 0.37 | 0.79 | 0.29 |
| SF-36 physical function score | |||
| Any neurological deficit | 26.5 (1.2) | 7.6 (1.3) | 19 (16.2 to 21.8) |
| No neurological deficit | 23.6 (1.3) | 11 (1.5) | 12.7 (9.7 to 15.7) |
| P value | 0.11 | 0.11 | 0.002 |
| Oswestry Disability Index | |||
| Any neurological deficit | −22.5 (0.9) | −7.2 (1.1) | −15.3 (−17.5 to −13.1) |
| No neurological deficit | −22.9 (1) | −9.4 (1.2) | −13.5 (−15.9 to −11.2) |
| P value | 0.78 | 0.20 | 0.27 |
*
The SF-36 scores range from 0 to 100 points, with higher scores indicating less severe symptoms. The Oswestry Disability Index ranges from 0 to 100 points, with lower scores indicating less severe symptoms.