Table 2.

Correlation with perceived pain improvement of back and leg

Perceived change	Change of VAS during 2 years
Total
Back	0.74
Leg	0.77
Group with >50% improvement
Back	0.46
Leg	0.54
Group with <50% improvement
Back	0.76
Leg	0.37

Notes: Perceived change of symptoms has been surveyed by 5-point Likert scale. The correlation (Spearman’s rho) was significant with P<0.05 in all instances.

Abbreviation: VAS, visual analog scale.