title: Spinal cord stimulation versus re-operation in patients with failed back surgery syndrome: an international multicenter randomized controlled trial (EVIDENCE study).
abstract: OBJECTIVE
  This paper presents the protocol of the EVIDENCE study, a multicenter multinational randomized controlled trial to assess the effectiveness and cost-effectiveness of spinal cord stimulation (SCS) with rechargeable pulse generator versus re-operation through 36-month follow-up in patients with failed back surgery syndrome.
  
  
  METHODS
  Study subjects have neuropathic radicular leg pain exceeding or equaling any low back pain and meet specified entry criteria. One-to-one randomization is stratified by site and by one or more prior lumbosacral operations. The sample size of 132 subjects may be adjusted to between 100 and 200 subjects using a standard adaptive design statistical method with pre-defined rules. Crossover treatment is possible. Co-primary endpoints are proportion of subjects reporting ≥ 50% leg pain relief without crossover at 6 and at 24 months after SCS screening trial or re-operation. Insufficient pain relief constitutes failure of randomized treatment, as does crossover. Secondary endpoints include cost-effectiveness; relief of leg, back, and overall pain; change in disability and quality of life; and rate of crossover. We are collecting data on subject global impression of change, patient satisfaction with treatment, employment status, pain/paresthesia overlap, SCS programming, and adverse events.
  
  
  CONCLUSIONS
  As the first multicenter randomized controlled trial of SCS versus re-operation and the first to use only rechargeable SCS pulse generators, the EVIDENCE study will provide up-to-date evidence on the treatment of failed back surgery syndrome.
authors: Berman Brain and Spine Institute and Johns Hopkins University School of Medicine (ret.), Baltimore, MD, USA. rnorth@lifebridgehealth.org
authors: Richard B
authors: RB
authors: North
authors: Krishna
authors: K
authors: Kumar
authors: Mark S
authors: MS
authors: Wallace
authors: Jaimie M
authors: JM
authors: Henderson
authors: Jane
authors: J
authors: Shipley
authors: John
authors: J
authors: Hernandez
authors: Nitzan
authors: N
authors: Mekel-Bobrov
authors: Kristen N
authors: KN
authors: Jaax
mesh_terms: D003362:Cost-Benefit Analysis; D004599:Electric Stimulation Therapy / Q000191:economics* / Q000379:methods; D055111:Failed Back Surgery Syndrome / Q000628:therapy*; D006801:Humans; D012086:Reoperation / Q000191:economics; D012107:Research Design; D013116:Spinal Cord / Q000502:physiology*