Table 3.

Comparison of clinical outcomes between satisfied and dissatisfied subgroups at midterm follow-up by univariate analysis

Variable		All patients (n=222)	Functional improvement			Relief of back pain
			Satisfied (n=206)	Dissatisfied (n=16)	p-value	Satisfied (n = 213)	Dissatisfied (n = 9)	p-value
ODI score
	Baseline	44.8 ± 19.9	45.6 ± 19.8	34.4 ± 18.8	0.030**	45.1 ± 19.8	34.4 ± 22.5	0.329
	At 2 years	3.2 ± 7.4	1.5 ± 3.2	24.8 ± 11.5	< 0.001**	2.2 ± 5.0	26.4 ± 14.5	0.005**
SF-36 PF score
	Baseline	52.1 ± 23.5	51.2 ± 23.1	64.7 ± 25.1	0.026**	51.7 ± 23.4	62.2 ± 24.5	0.189
	At 2 years	97.5 ± 5.1	98.5 ± 2.7	84.4 ± 9.6	< 0.001**	98.1 ± 3.7	82.8 ± 10.9	0.003**
SF-36 BP score
	Baseline	46.5 ± 19.0	45.7 ± 19.1	57.4 ± 14.7	0.017**	46.0 ± 19.1	59.6 ± 13.1	0.035**
	At 2 years	96.0 ± 9.3	98.0 ± 5.0	70.1 ± 12.7	< 0.001**	97.2 ± 7.1	68.0 ± 11.8	< 0.001**
EQ-5D score
	Baseline	0.53 ± 0.22	0.52 ± 0.23	0.63 ± 0.15	0.063*	0.52 ± 0.22	0.66 ± 0.13	0.070*
	At 2 years	0.97 ± 0.07	0.99 ± 0.04	0.80 ± 0.12	< 0.001**	0.98 ± 0.05	0.77 ± 0.12	< 0.001**
VAS-back score
	Baseline	3.94 ± 2.42	3.96 ± 2.42	3.69 ± 2.50	0.668	3.94 ± 2.42	3.89 ± 2.47	0.950
	At 2 years	0.37 ± 0.86	0.20 ± 0.50	2.56 ± 1.41	< 0.001**	0.23 ± 0.51	3.67 ± 0.87	< 0.001**
VAS-leg score
	Baseline	5.40 ± 1.92	5.40 ± 1.96	5.38 ± 1.41	0.963	5.42 ± 1.92	4.78 ± 2.12	0.326
	At 2 years	0.19 ± 0.56	0.09 ± 0.31	1.44 ± 1.21	< 0.001**	0.15 ± 0.49	1.11 ± 1.17	0.038**

Values are presented as mean±standard deviation.

ODI, Oswestry Disability Index; SF-36 PF; 36-item Short Form Health Survey physical function; SF-36 BP, 36-item Short Form Health Survey bodily pain; EQ-5D, European quality of life-5 dimensions; VAS, visual analogue scale.

^*p<0.1.

^**p<0.05.