Patient self-reported outcomes of the 2 cage groups.
| Study Arm | Changesa in ODI (%): Mean (Range, SD) | ||
| 3 mo | 6 mo | 12 mo | |
| Expandable cage | −14.61 (−48 to 28, 14.5) | −19.03 (−58 to 4, 14.6) | −20.81 (−60 to 8, 16.6) |
| Static cage | −10.41 (−28 to 16, 16.5) | −16.21 (−52 to 14, 19.5) | −20.24 (−58 to 42, 22.1) |
| P value | 0.289 | 0.541 | 0.894 |
| Changesa in VAS—Back: Mean (Range, SD) | |||
| 3 mo | 6 mo | 12 mo | |
| Expandable cage | −4.46 (−9 to 2, 2.7) | −4.65 (−9 to 0, 3.0) | −5.20 (−10 to 6, 3.3) |
| Static cage | −2.5 (−9 to 2, 2.8) | −3.71 (−9 to 1, 2.7) | −3.32 (−9 to 5, 3.4) |
| P value | 0.006 | 0.231 | 0.062 |
| Changesa in VAS—Both Legs Combined: Mean (Range, SD) | |||
| 3 mo | 6 mo | 12 mo | |
| Expandable cage | −6.70 (−18 to 9, 6.8) | −6.22 (−17 to 4, 5.5) | −6.76 (−18 to 4, 4.6) |
| Static cage | −5.46 (−13 to 1, 3.9) | −5.55 (−13 to 2, 4.3) | −4.27 (−14 to 9, 5.1) |
| P value | 0.447 | 0.654 | 0.023 |
| Changes*a in SF-12 (PCS): Mean (Range, SD) | |||
| 3 mo | 6 mo | 12 mo | |
| Expandable cage | 7.46 (−34.2 to 29.3, 10.2) | 13.24 (−13.1 to 38.9, 10.0) | 10.39 (−27.8 to 37.9, 14.6) |
| Static cage | 7.12 (−3.4 to 21.2, 7.0) | 5.80 (−25.7 to 22, 12.5) | 12.68 (−7.4 to 37, 10.7) |
| P value | 0.624 | 0.035 | 0.988 |
| Changesa in SF-12 (MCS): Mean (Range, SD) | |||
| 3 mo | 6 mo | 12 mo | |
| Expandable cage | 4.54 (−63.6 to 22.41, 14.1) | 4.13 (−47.3 to 28.6, 14.1) | 6.24 (−28.9 to 28.6, 13.4) |
| Static cage | −0.72 (−26.1 to 22.7, 10.6) | 2.75 (−67.1 to 20.0, 20.3) | 3.08 (−23 to 38.0, 13.2) |
| P value | 0.009 | 0.026 | 0.273 |
↵a The value of the change is the difference between the score at the targeted follow-up minus preoperative baseline score. ODI (a score of 0–100, with higher scores indicating worse disability); VAS (a score of 0–20 for both legs combined, with higher scores indicating more severe pain); PCS (range of 0–100, with higher scores indicating better physical health functioning); MCS (range of 0–100, with higher scores indicating better mental health functioning).
MCS, mental component score; ODI, Oswestry Disability Index; PCS, physical component score; SF-12, 12-Item short form survey; VAS, visual analog scale.