Minimum clinically important difference.
| Patient-Reported Outcome Measures | LOS ≥45 h, % (n) | LOS <45 h, % (n) | P Valuea |
| ODI | |||
| 6 wk | 28.6% (2) | 71.4% (5) | 0.703 |
| 12 wk | 10.0% (1) | 90.0% (9) | 0.375 |
| 6 mo | 37.5% (3) | 62.5% (5) | 0.561 |
| 1 y | 14.3% (1) | 85.7% (6) | 0.515 |
| 2 y | 0.0% (0) | 0.0% (0) | - |
| Overall | 17.7% (3) | 82.4% (14) | 0.004 |
| PROMIS-PF | |||
| 6 wk | 9.1% (1) | 90.9% (10) | 0.747 |
| 12 wk | 22.2% (2) | 77.8% (7) | 0.964 |
| 6 mo | 16.7% (2) | 83.3% (10) | 0.137 |
| 1 y | 22.2% (2) | 77.8% (7) | 0.480 |
| 2 y | 33.3% (1) | 66.7% (2) | 1.000 |
| Overall | 18.2% (4) | 81.8% (18) | 0.001 |
| SF-12 PCS | |||
| 6 wk | 25.0% (3) | 75.0% (9) | 0.527 |
| 12 wk | 14.3% (2) | 85.7% (12) | 0.490 |
| 6 mo | 32.3% (6) | 64.7% (11) | 0.394 |
| 1 y | 11.1% (1) | 88.9% (8) | 0.522 |
| 2 y | 25.0% (1) | 75.0% (3) | 0.809 |
| Overall | 24.1% (7) | 75.9% (22) | 0.001 |
| VAS back | |||
| 6 wk | 44.0% (22) | 56.0% (28) | 0.201 |
| 12 wk | 47.1% (24) | 52.9% (27) | 0.566 |
| 6 mo | 51.1% (23) | 48.9% (22) | 0.222 |
| 1 y | 22.2% (2) | 77.8% (7) | 0.913 |
| 2 y | 0.0% (0) | 100.0% (1) | 0.505 |
| Overall | 43.7% (31) | 56.3% (40) | 0.058 |
| VAS leg | |||
| 6 wk | 31.3% (5) | 68.8% (11) | 0.312 |
| 12 wk | 18.8% (3) | 81.3% (13) | 0.925 |
| 6 mo | 33.3% (5) | 66.7% (10) | 0.637 |
| 1 y | 25.0% (2) | 75.0% (6) | 0.707 |
| 2 y | 100.0% (1) | 100.0% (1) | - |
| Overall | 27.6% (8) | 72.4% (21) | 0.004 |
Note: Boldface indicates statistical significance.
↵a P values calculated using χ 2 analysis.
LOS, length of stay; ODI, Oswestry Disability Index; PROMIS-PF, patient-reported outcome measurement information system physical function; SF-12 PCS, 12-item short form physical composite score; VAS, visual analog scale.