Table 3. Subgroup results from common adjusting covariates* as-treated outcome analysis by number of levels with moderate or severe stenosis for the randomized and observational SPS cohorts combined.
Analysis results from adjusted as-treated outcome analysis by number of levels with moderate or severe stenosis for the randomized and observational cohort for patients with isolated spinal stenosis.
| SPS cohort | 3-Months | 1-Year | 2-Year | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Outcomes | Stenosis Level | Surgical | Non-operative | Treatment Effect** (95% CI) | Surgical | Non-operative | Treatment Effect** (95% CI) | Surgical | Non-operative | Treatment Effect** (95% CI) |
| SF-36 Bodily Pain (BP) (0-100(SE)† | One | 31 (2) | 13.2 (2.1) | 17.8 (12.8, 22.9) | 29.6 (2.2) | 16.8 (2.4) | 12.8 (7, 18.6) | 28.6 (2.1) | 17.3 (2.5) | 11.2 (5.2, 17.3) |
| Two | 27.9 (1.9) | 12 (2) | 15.9 (11, 20.8) | 27.6 (2.1) | 11.5 (2.4) | 16.1 (10.3, 21.9) | 27.9 (2.1) | 12.8 (2.5) | 15.1 (9, 21.1) | |
| Three+ | 30.5 (2.5) | 15 (2.9) | 15.5 (8.8, 22.3) | 33.8 (2.5) | 16.4 (3.2) | 17.4 (9.8, 25.1) | 28.7 (2.5) | 13.9 (3.4) | 14.7 (6.9, 22.6) | |
| pvalue | 0.49 | 0.69 | 0.81 | 0.16 | 0.23 | 0.58 | 0.96 | 0.43 | 0.63 | |
| SF-36 Physical Function (PF) (0-100) (SE)† | One | 25.3 (1.9) | 11.7 (2) | 13.7 (9, 18.3) | 26.4 (2.1) | 12.9 (2.2) | 13.5 (8.1, 18.9) | 23 (2) | 13.7 (2.4) | 9.3 (3.7, 15) |
| Two | 22.7 (1.8) | 8.1 (1.9) | 14.6 (10, 19.1) | 23.2 (2) | 9.3 (2.2) | 13.9 (8.6, 19.3) | 21.5 (2) | 10.5 (2.4) | 11 (5.4, 16.6) | |
| Three+ | 26.8 (2.4) | 10.5 (2.7) | 16.4 (10.1, 22.6) | 30.6 (2.4) | 9.4 (3.1) | 21.3 (14.1, 28.4) | 25.2 (2.4) | 10.4 (3.2) | 14.7 (7.4, 22.1) | |
| pvalue | 0.34 | 0.42 | 0.79 | 0.057 | 0.47 | 0.18 | 0.48 | 0.59 | 0.51 | |
| Mental Component Summary (MCS) (0-100) (SE)† | One | 3.9 (0.8) | 2.2 (0.9) | 1.7 (-0.5, 3.8) | 2.8 (0.9) | 2.6 (1) | 0.2 (-2.2, 2.7) | 2.8 (0.9) | 1.5 (1) | 1.3 (-1.3, 3.9) |
| Two | 4 (0.8) | 1.5 (0.8) | 2.5 (0.4, 4.6) | 3.6 (0.9) | 1.2 (1) | 2.4 (-0.1, 4.8) | 4 (0.9) | 1.7 (1) | 2.2 (-0.3, 4.8) | |
| Three+ | 4.2 (1) | 2.4 (1.2) | 1.8 (-1.1, 4.6) | 5.1 (1) | 3.5 (1.3) | 1.6 (-1.6, 4.8) | 4.7 (1) | -0.4 (1.4) | 5.1 (1.8, 8.4) | |
| pvalue | 0.98 | 0.79 | 0.84 | 0.27 | 0.34 | 0.46 | 0.35 | 0.43 | 0.19 | |
| Oswestry Disability Index (ODI) (0-100) (SE)‡ | One | -20.6 (1.6) | -8.9 (1.6) | -11.7 (-15.5, -7.9) | -19.9 (1.7) | -10.6 (1.8) | -9.3 (-13.7, -4.9) | -19.8 (1.6) | -10.4 (1.9) | -9.4 (-14, -4.8) |
| Two | -21.3 (1.5) | -5.1 (1.6) | -16.2 (-19.9, -12.5) | -20.6 (1.6) | -7.4 (1.8) | -13.2 (-17.6, -8.8) | -20.2 (1.6) | -9.4 (1.9) | -10.7 (-15.3, -6.2) | |
| Three+ | -22.4 (1.9) | -9.6 (2.2) | -12.8 (-17.9, -7.7) | -24.4 (2) | -8.4 (2.5) | -16 (-21.8, -10.2) | -21.9 (1.9) | -6.3 (2.6) | -15.7 (-21.6, -9.7) | |
| pvalue | 0.78 | 0.12 | 0.21 | 0.19 | 0.46 | 0.17 | 0.68 | 0.45 | 0.25 | |
| Stenosis Frequency Index (0-24) (SE)§ | One | -7.7 (0.7) | -3.3 (0.6) | -4.4 (-6, -2.8) | -7.3 (0.6) | -3.8 (0.6) | -3.4 (-5, -1.8) | -6.9 (0.6) | -4.4 (0.7) | -2.6 (-4.3, -0.9) |
| Two | -7.5 (0.7) | -2 (0.6) | -5.5 (-7.2, -3.8) | -7 (0.6) | -2.9 (0.6) | -4.1 (-5.7, -2.5) | -7.3 (0.6) | -3.9 (0.7) | -3.3 (-5.1, -1.6) | |
| Three+ | -8.6 (0.8) | -3.5 (0.8) | -5 (-7.2, -2.9) | -8.3 (0.7) | -4.1 (0.9) | -4.2 (-6.3, -2.1) | -7.4 (0.7) | -2.8 (0.9) | -4.6 (-6.8, -2.4) | |
| pvalue | 0.60 | 0.13 | 0.65 | 0.30 | 0.43 | 0.79 | 0.85 | 0.43 | 0.35 | |
| Stenosis Bothersomeness Index (0-24) (SE)§ | One | -8.4 (0.7) | -3.4 (0.6) | -4.9 (-6.6, -3.3) | -8.2 (0.6) | -4 (0.6) | -4.2 (-5.8, -2.6) | -7.4 (0.6) | -4.5 (0.7) | -2.8 (-4.5,-1.1) |
| Two | -8.5 (0.7) | -2.2 (0.6) | -6.3 (-8, -4.5) | -7.7 (0.6) | -3.7 (0.7) | -4.1 (-5.7, -2.4) | -8.1 (0.6) | -4.3 (0.7) | -3.7 (-5.5, -2) | |
| Three+ | -8.9 (0.8) | -3.2 (0.8) | -5.7 (-7.8, -3.5) | -9 (0.7) | -3.9 (0.9) | -5.2 (-7.3, -3) | -8 (0.7) | -4.1 (0.9) | -3.9 (-6.1, -1.7) | |
| pvalue | 0.89 | 0.27 | 0.53 | 0.33 | 0.95 | 0.68 | 0.66 | 0.92 | 0.66 | |
| Low Back Pain Bothersomeness (0-6) (SE)¶ | One | -1.8 (0.2) | -0.8 (0.2) | -1 (-1.5, -0.5) | -2 (0.2) | -1 (0.2) | -1 (-1.5, -0.5) | -2.1 (0.2) | -1.3 (0.2) | -0.8 (-1.3, -0.3) |
| Two | -2.2 (0.2) | -0.8 (0.2) | -1.4 (-1.9, -0.9) | -1.9 (0.2) | -1.1 (0.2) | -0.8 (-1.3, -0.3) | -1.9 (0.2) | -1.1 (0.2) | -0.8 (-1.3, -0.3) | |
| Three+ | -2 (0.2) | -1 (0.2) | -1 (-1.6, -0.4) | -2.2 (0.2) | -1 (0.3) | -1.2 (-1.8, -0.6) | -2.1 (0.2) | -0.8 (0.3) | -1.3 (-1.9, -0.7) | |
| pvalue | 0.42 | 0.64 | 0.43 | 0.39 | 0.94 | 0.58 | 0.75 | 0.28 | 0.35 | |
| Very/somewhat satisfied with symptoms (%) | One | 62.1 | 24.7 | 37.4 (26.1, 48.7) | 67.3 | 28.9 | 38.4 (25.4, 51.4) | 63.8 | 44.7 | 19.1 (4.3, 33.9) |
| Two | 63.2 | 21.7 | 41.5 (30.8, 52.2) | 62.3 | 29.7 | 32.6 (19.3, 45.8) | 71.5 | 22 | 49.5 (37, 62) | |
| Three+ | 56.1 | 24.9 | 31.2 (16.3, 46.1) | 75.3 | 32.1 | 43.2 (26.7, 59.7) | 69 | 21.2 | 47.8 (32, 63.6) | |
| pvalue | 0.59 | 0.83 | 0.57 | 0.19 | 0.93 | 0.61 | 0.48 | 0.01 | 0.005 | |
| Self-rated progress major improvement (%) | One | 72.4 | 23.9 | 48.4 (38, 58.9) | 65.9 | 27.6 | 38.3 (25.6, 51) | 62.3 | 36.2 | 26.1 (12.1, 40.2) |
| Two | 70.4 | 17.6 | 52.8 (43.2, 62.4) | 66.1 | 24.8 | 41.3 (29, 53.7) | 64.7 | 25.2 | 39.5 (26.5, 52.5) | |
| Three+ | 71.6 | 17.3 | 54.2 (41.4, 67.1) | 74.6 | 26.4 | 48.2 (32.7, 63.8) | 59.4 | 24.5 | 34.9 (18.2, 51.6) | |
| pvalue | 0.95 | 0.43 | 0.70 | 0.39 | 0.92 | 0.63 | 0.77 | 0.30 | 0.42 | |
Adjusted for age, gender, stomach comorbidity, SLR or femoral tension sign, smoking status, joint comorbidity, patient self assessed health trend, income, compensation, bmi, baseline score (for SF-36 and ODI), and center.
The SF-36 scores range from 0 to 100, with higher score indicating less severe symptoms.
The Oswestry Disability Index ranges from 1 to 100, with lower scores indicating less severe symptoms.
The Stenosis Bothersomeness Index and the Stenosis Frequency Index range from 0 to 24, with lower scores indicating less severe symptoms.
The Low Back Pain Bothersomness Scale ranges from 0 to 6, with lower scores indicating less severe symptoms
Treatment effect is the difference between the surgical and non-operative mean change from baseline. Analysis is done using a mixed model with a random subject intercept term. Treatment is a time-varying covariate where a patients' experience prior to surgery is attributed to the non-operative arm and time is measured from enrollment and his/her post-surgery outcomes are attributed to the surgical arm and time is measured from time of surgery.