Evaluation of central (cerebral) effects of Pulsed RadioFrequency (PRF) on the lumbar DRG (Dorsal Root Ganglion), using fMRI (functional Magnetic Resonance Imaging ). Feasibility study (after which an interim analysis is done): 5 subjects in order to detect measurable central effects inducted by PRF on DRG, follow up study 20. Total amount of subjects 25.

Detect and prove the central effects of PRF and show the objective working mechanism.

PRF is often used technique to alleviate chronic radicular neuropathic pain, although good clinical results are observed the precise (central ) working mechanism is still unknown. This study aims to find the central working mechanism.

The investigator postulate the existence of central -cerebral effect of PRF on the DRG (dorsal root ganglion). If the investigator can detect the effect using fMRI and demonstrate the objective unequivocal proof that PRF on the DRG works than the investigator will be able to promote this technique for further use in the chronic pain states.

Inclusion Criteria:

• 18-75 y
• Radicular pain in lumbar region more than 6 weeks, neuropathic

Exclusion Criteria:

• Coagulopathy
• Implanted PM or SCS device
• Pregnancy
• Unwilling to undergo MRI
• Psychiatric disorders