title: Altering Conventional to High Density Spinal Cord Stimulation: An Energy Dose-Response Relationship in Neuropathic Pain Therapy.
abstract: OBJECTIVE
  To examine whether converting from conventional Spinal Cord Stimulation (SCS) to High Density (HD) SCS reduces neuropathic pain over a period of 12 months in patients with failed SCS therapy.
  
  
  METHODS
  Retrospective, open label, single center, consecutive case series of 30 neuropathic pain patients (Failed Back Surgery Syndrome [FBSS], Complex Regional Pain Syndrome [CRPS], and polyneuropathy [NP]). Patients with an initial adequate response to conventional SCS, but in whom pain increased over time, were included (Numeric Rating Scales [NRS] >6). These patients were stimulated with HD-SCS parameters and followed-up for 12 months. We report pain intensity, measured with NRS, before SCS implantation, 1 and 3 months after starting SCS with conventional stimulation, and after 1, 6, and 12 months of HD SCS.
  
  
  RESULTS
  Pain reduction with conventional stimulation was initially adequate (NRS mean 8.6 to 5.3 at three months postimplant) but increased over time to a mean NRS of 7.7 at the time of reprogramming. NRS scores decreased significantly to 4.3 (p = 0.015) after reprogramming from conventional SCS (30 Hz, 300 µsec, 3.0 V) to HD SCS (409 Hz, range 130-1000 Hz, 409 µsec, 2.4V) in the patients still using HD-SCS at 12 months. In the nonresponders (patients who stopped HD-SCS for any reason), 76% had a diagnosis of FBSS. Almost half of the patients aborting HD-SCS preferred to feel paresthesias despite better pain relief. There was a significant difference between nonresponders and responders regarding the amount of electrical energy delivered to the spinal cord.
  
  
  CONCLUSIONS
  Neuropathic pain suppression is significantly enhanced after converting from failed conventional SCS to HD SCS in patients with FBSS, CRPS, and NP over a measured period of 12 months. There appears to be a dose-related response between the amount of energy delivered to the spinal cord and clinical effect.
authors: Department of Anesthesiology-Pain Medicine, Diakonessenhuis Zeist, Zeist, The Netherlands.|Department of Anesthesiology-Pain Medicine, Academic Medical Center (AMC) Amsterdam, Amsterdam, The Netherlands.
authors: Frank
authors: F
authors: Wille
authors: Department of Anesthesiology-Pain Medicine, Diakonessenhuis Zeist, Zeist, The Netherlands.|Department of Anesthesiology-Pain Medicine, Academic Medical Center (AMC) Amsterdam, Amsterdam, The Netherlands.
authors: Jennifer S
authors: JS
authors: Breel
authors: Division Clinical Methods and Public Health, Department of Clinical Epidemiology, Biostatistics and Bioinformatics, University of Amsterdam, Faculty of Medicine, Academic Medical Center (AMC), Amsterdam, The Netherlands.
authors: Eric W P
authors: EW
authors: Bakker
authors: Department of Anesthesiology-Pain Medicine, Academic Medical Center (AMC) Amsterdam, Amsterdam, The Netherlands.
authors: Markus W
authors: MW
authors: Hollmann
mesh_terms: D055592:Biophysical Phenomena / Q000502:physiology*; D015331:Cohort Studies; D004567:Electrodes, Implanted; D055111:Failed Back Surgery Syndrome / Q000628:therapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009437:Neuralgia / Q000628:therapy*; D010147:Pain Measurement; D062187:Spinal Cord Stimulation / Q000379:methods*; D016896:Treatment Outcome
keywords: Charge per second; complex regional pain syndrome; failed back surgery syndrome; high density; invasive pain management; neuromodulation; pulse density