5.4. Statistical Analysis 
PNE, pain
The data were analyzed with IBM SPSS Statistics 20. The sample size was estimated expecting to find a decrease in two or more pain points in VAS, after injection of BTA (BTA group) or PNE puncture (PNE group), which had to be present within a month after treatment. Considering a significance level of 5% and equivalence limit of 1.35, a one-sided double-equivalence Student’s 