Table 5.

Duration of back pain and outcome measures at 1-year follow-up

Duration of pain pre-operatively	EuroQol-5D	Oswestry disability index	Leg pain	Back pain	Walking distance
Up to 2 years	0.64 (0.27)	28 (20)	33 (31)	32 (31)	2.6 (1.1)
n =	43	27	48	49	52
Over 2 years	0.54 (0.25)	35 (19)	44 (33)	40 (30)	2.2 (1.2)
n =	42	34	46	47	50
p-value	0.04	0.09	0.1	0.1	0.06
95% CI for differenc in medians a	–0.03 to 0.1	–22 to 6	–41 to 14	–37 to 9	0 to 1.5

Two-sample Wilcoxon rank-sum test.

Standard deviation in parentheses.

^a Stratified bootstrap test for difference in medians.