New Markers to Assess the Efficacity of Spinal Cord Stimulation for the Treatment of Chronic Lower Limb Pain (MOTIVE)

Inclusion Criteria: * Lower limb pain included in the inclusion criteria for spinal cord stimulation according to HAS recommendations: neuropathic, lumbar radicular sequelae after spinal surgery, complex regional pain syndrome (CRPS) * Chronic pain that has been present for at least 6 months * Rebellious pain resistant to drug and non-drug treatments well conducted; * Functional impact defined by a score\> 20% on the Oswestry scale; * Patient affiliated or beneficiary of a social security scheme; * Patient who consented to participate in the study. Exclusion Criteria: * Presence of a surgical contraindication to the implantation of material (chronic infection, long-term anticoagulant treatment that cannot be interrupted, contraindication to anesthesia); * Addiction (according to DSM IV); * Major depressive syndrome despite appropriate treatment and / or psychotic symptoms (according to DSM IV); * Unbalanced psychiatric disorder; * Intermittent pain or present for less than 6 months; * Diffuse painful syndrome; * Progressive disease, associated inflammatory rheumatic pathology, and any other disabling pathology limiting physical activity (advanced articular osteoarthritis); * Absolute contraindication to MRI (e.g. pace-maker, implantable stimulator, intra-orbital metallic foreign body); * Language barrier or cognitive disorders preventing understanding of the research protocol; * Person benefiting from a legal protection measure; * Pregnant or breastfeeding woman.