Statistical analysis
LMBB
The primary endpoint was to investigate the non-inferiority of the US group, comparing to the FS group in regard to the evolution of the ODI measured 1 month after the LMBB. Power analysis was performed with a projected standard deviation of 7. If there was truly no difference between the standard and experimental treatment, then 50 patients are required to be 80% sure that the lower limit of a one-sided 95% confidence interval (or equivalently a 90% two-sided confidence interval) will be under the non-inferiority limit of + 5 points. Analysis of non-inferiority was realized with a one-sided Mann-Whitney test.All data for the ODI, the VAPS and the DASI measured before, 1 week and 1month after the LMBB were compared by an analysis of variance for repeated measures with mixed models with treatment arms, time, thermocoagulation status, time x treatment interaction, thermocoagulation status x time interaction and time x treatment x thermocoagulation status interaction terms.Categorical data were compared by a χ