Spinal cord stimulation versus re-operation in patients with failed back surgery syndrome: an international multicenter randomized controlled trial (EVIDENCE study)

Neuromodulation. 2011 Jul-Aug;14(4):330-5; discussion 335-6. doi: 10.1111/j.1525-1403.2011.00371.x. Epub 2011 Jul 7.


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.

Study design: 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.

Discussion: 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.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cost-Benefit Analysis
  • Electric Stimulation Therapy / economics*
  • Electric Stimulation Therapy / methods
  • Failed Back Surgery Syndrome / therapy*
  • Humans
  • Reoperation / economics
  • Research Design
  • Spinal Cord / physiology*