The subjects will then be followed for 12 months to assess the long-term treatment outcome. Follow up visits will occur at 1, 3, 6 and 12 months after permanent implant. During each of these visits subjects will rate their pain using the VAS, their quality of life using the EQ-5D, their disability using the ODI, Neuropathic pain using DN4 , Mental health using SF-36 and sensation using paraesthesia Map.