This study was a randomized, double-blinded, placebo-controlled phase 3 trial comparing BoNT-A Type A injections to a placebo in patients with chronic Low-back Pain (LBP). This superiority trial obtained support from the French Hospital Clinical Research Project (PHRC) and the approval of a French ethics committee (2003/02) ("Comité Sud-Ouest et Outre-Mer III", consent obtained in February 2003).