Table 2

Improvement of outcome measures.

Outcome measure	n	Mean ± SD	P value^a
VAS back
Preoperative	712	6.27 ± 2.45	<0.001
6 wk	594	2.78 ± 2.57	<0.001
12 wk	321	3.05 ± 2.83	<0.001
6 mo	221	3.20 ± 2.92	<0.001
1 y	121	3.27 ± 2.89	<0.001
VAS leg
Preoperative	476	6.17 ± 2.57	<0.001
6 wk	377	2.87± 2.80	<0.001
12 wk	216	2.93 ± 2.87	<0.001
6 mo	164	3.12 ± 2.92	<0.001
1 y	120	2.77 ± 2.90	<0.001
ODI
Preoperative	494	42.2 ± 17.6	<0.001
6 wk	391	25.0 ± 18.2	<0.001
12 wk	226	24.8 ± 20.8	<0.001
6 mo	170	31.9 ± 77.5	0.054
1 y	120	23.0 ± 20.8	<0.001
SF-12 PCS
Preoperative	446	31.7 ± 7.91	<0.001
6 wk	288	38.2 ± 10.1	<0.001
12 wk	168	41.1 ± 10.9	<0.001
6 mo	146	40.7 ± 11.2	<0.001
1 y	141	42.3 ± 10.9	<0.001
PROMIS PF
Preoperative	304	36.3 ± 6.8	<0.001
6 wk	212	42.7 ± 8.4	<0.001
12 wk	124	45.6 ± 10.1	<0.001
6 mo	111	43.4 ± 9.8	<0.001
1 y	101	45.5 ± 10.1	<0.001

Boldface indicates statistical significance.
aP values calculated difference from baseline values using paired t test.
ODI, Oswestry Disability Index; PROMIS PF, patient-reported outcomes measures information system physical function; SF-12, 12-item short form; VAS, visual analog scale.