“…Only few studies report a precocious reduction of the pain : within a week, according to Brocq (Brocq et al, 2002) (-27 %), and within the first 2 -4 weeks according to Qvistgaard (Qvistgaard et al, 2001) (-14 % and -32 %, respectively). The positive effects on pain after 1 -3 months range from -16.1 % to -52.2 % (mean -37.2 %), whereas, overall, the mean Visual Analogic Scale score decreases about 49 % after 3 -6 months (range 31 -80 %) (Abate et al, 2008). Therefore, it seems that the benefit increases in the long term.…”