Effects of Rate on Analgesia in Kilohertz Frequency Spinal Cord Stimulation: Results of the PROCO Randomized Controlled Trial

Neuromodulation. 2018 Jan;21(1):67-76. doi: 10.1111/ner.12746. Epub 2017 Dec 8.


Objective: The PROCO RCT is a multicenter, double-blind, crossover, randomized controlled trial (RCT) that investigated the effects of rate on analgesia in kilohertz frequency (1-10 kHz) spinal cord stimulation (SCS).

Materials and methods: Patients were implanted with SCS systems and underwent an eight-week search to identify the best location ("sweet spot") of stimulation at 10 kHz within the searched region (T8-T11). An electronic diary (e-diary) prompted patients for pain scores three times per day. Patients who responded to 10 kHz per e-diary numeric rating scale (ED-NRS) pain scores proceeded to double-blind rate randomization. Patients received 1, 4, 7, and 10 kHz SCS at the same sweet spot found for 10 kHz in randomized order (four weeks at each frequency). For each frequency, pulse width and amplitude were titrated to optimize therapy.

Results: All frequencies provided equivalent pain relief as measured by ED-NRS (p ≤ 0.002). However, mean charge per second differed across frequencies, with 1 kHz SCS requiring 60-70% less charge than higher frequencies (p ≤ 0.0002).

Conclusions: The PROCO RCT provides Level I evidence for equivalent pain relief from 1 to 10 kHz with appropriate titration of pulse width and amplitude. 1 kHz required significantly less charge than higher frequencies.

Keywords: Chronic pain; PROCO; double-blind; high frequency; high frequency SCS; kilohertz SCS; randomized controlled trial; sub-perception SCS.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Aged
  • Analgesia / methods*
  • Chronic Pain / psychology
  • Chronic Pain / therapy*
  • Cross-Over Studies
  • Double-Blind Method
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Middle Aged
  • Pain Measurement
  • Pain Threshold / physiology
  • Quality of Life / psychology
  • Spinal Cord Stimulation / methods*
  • Treatment Outcome*