Aberrant Neuronal Branching clinical trials

CRF vs WCRF or PRF-DRG in CLBP of FJ Origin and RFA Failure of MBDR: Central Sensitization and Aberrant Nerve Sprouting

The investigators will select two study groups from a population of patients with severe chronic low back pain (CLBP) of facet joint (FJ) origin already treated with conventional radiofrequency ablation (CRFA) of the medial branch of the dorsal ramus (MBDR) and that failed to obtain a 50% pain reduction measured through the numerical rate scale (NRS) for at least 3 months. Severe CLBP is considered a value of at least 7 by NRS pain assessment. The first group will be characterized by a nociceptive/mechanic type of back pain. The second group of study will be characterized by a neuropathic type of back pain. This difference will be established by a DN4 score of at least 4 points (Doleur Neurophatique 4). The patients in the group with nociceptive/mechanic back pain will be randomly assigned to conventional radiofrequency ablation or to water cooled radiofrequency (WCRF) of the MBDR. The patients in the group with neuropathic back pain will be randomly assigned CRFA of MBDR or to pulsed radiofrequency (PRF) of the dorsal root ganglia (DRG). The study will be carried on for an estimated time of 3 years. Primary outcomes will be: - at least 50% back pain reduction for at least 3 months evaluated through NRS, with a subcategorization of results that will consider a mean difference in effect (respect to the initial evaluation, with an initial NRS score of at least 7) of 1 point on NRS pain scale as small/modest, 2 points as moderate, more than 2 as large/substantial between the case/control study groups. - improvement of low back pain disability: 10 points increase on the Oswestry Low Back Pain Disability Questionnaire (ODI) have been proposed as minimal clinically important differences, between 10 and 20 as moderate, more than 20 as large/substantial clinical improvement at month 3 and 6. Secondary outcome will be evaluated by the 12-item short form survey SF12, accordingly with the clinical pre-interventional findings, analgesic intake at month 1-3-6 (if increased, unchanged, decreased, in dosages or number of pain killers' assumption). Groups sizes: will be calculated based on the disease's incidence and the outcome targets.