title: Effects of sub-perception threshold spinal cord stimulation in neuropathic pain: a randomized controlled double-blind crossover study.
abstract: BACKGROUND
  Recent studies suggest that perception of the paraesthesia elicited by spinal cord stimulation (SCS) is not necessarily required for the pain relieving effect.
  
  
  OBJECTIVE
  The purpose of the study was to determine the effect of sub-perception threshold SCS in patients with neuropathic pain.
  
  
  METHODS
  Ten patients with implanted SCS systems underwent continuous sub-threshold stimulation and no stimulation in a blinded randomized crossover design. Pain scores under these treatment modalities were compared with usual supra-threshold stimulation.
  
  
  RESULTS
  Sub-threshold stimulation elicited significantly lower pain relief than supra-perception threshold SCS. Mean pain scores were 3.6 [max 6.3, min 1.9, standard deviation (SD) 1.3] under supra-threshold stimulation, 5.6 (max 9.0, min 2.4, SD 1.9) under sub-threshold stimulation and 6.4 (max 10.0, min 4.0, SD 2.0) without stimulation.
  
  
  CONCLUSIONS
  Sub-threshold stimulation under otherwise conventional stimulation parameters has a measurable but not clinically sufficient effect. Thus, the pain relieving effect elicited by SCS is not necessarily linked to the perceptibility of stimulation but may instead be attributed to the intensity of the electric field.
authors.affiliation: Interdisciplinary Pain Center, University Hospital Freiburg, Freiburg, Germany. tilman.wolter@uniklinik-freiburg.de
authors.forename: T
authors.initials: T
authors.lastname: Wolter
authors.forename: A
authors.initials: A
authors.lastname: Kiemen
authors.forename: C
authors.initials: C
authors.lastname: Porzelius
authors.forename: H
authors.initials: H
authors.lastname: Kaube
mesh_terms: D000328:Adult; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004599:Electric Stimulation Therapy / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009437:Neuralgia / Q000503:physiopathology / Q000628:therapy*; D059408:Pain Management; D010147:Pain Measurement; D058748:Pain Perception / Q000502:physiology*; D013116:Spinal Cord / Q000503:physiopathology*; D016896:Treatment Outcome