TABLE IV.

Treatment Effect After Surgery for Primary Outcome Measures According to Duration of Symptoms

	Mean Treatment Effect (95% CI*)
Outcome Scale	1 Year	2 Years	3 Years	4 Years
SF-36 bodily pain
Patients with symptoms for ≤6 months	15.6 (12.1 to 19)	12.8 (9.3 to 16.3)	13.6 (10 to 17.3)	16.5 (12.8 to 20.3)
Patients with symptoms for >6 months	17.5 (12.1 to 22.9)	17.7 (12.2 to 23.2)	18 (12.1 to 23.9)	20.6 (14.5 to 26.6)
P value	0.55	0.14	0.21	0.26
SF-36 physical function
Patients with symptoms for ≤6 months	20 (16.8 to 23.3)	16.8 (13.5 to 20.1)	16.8 (13.4 to 20.2)	18.2 (14.7 to 21.7)
Patients with symptoms for >6 months	17 (12 to 22)	16.3 (11.2 to 21.4)	16.5 (11 to 22.1)	18.6 (13 to 24.2)
P value	0.31	0.86	0.94	0.91
Oswestry Disability Index
Patients with symptomsfor ≤6 months	−17.2 (−19.9 to −14.6)	−15 (−17.7 to −12.3)	−5 (−17.8 to −12.2)	−16.3 (−19.2 to −13.4)
Patients with symptoms for >6 months	−18.1 (−22.2 to −14)	−16.7 (−20.8 to −12.5)	−16.9 (−21.4 to −12.4)	−16.1 (−20.6 to −11.6)
P value	0.72	0.5	0.46	0.96

^*CI = confidence interval.