title: Efficacy of kilohertz-frequency and conventional spinal cord stimulation in rat models of different pain conditions.
abstract: OBJECTIVE
  The aim was to compare the effects of high-frequency spinal cord stimulation (HF-SCS) at subparesthetic intensity with conventional SCS in rat models of different types of pain. In addition, microrecordings of afferent activity in the dorsal columns during both types of SCS were performed to elucidate their mode of action.
  
  
  METHODS
  Miniature SCS electrodes were implanted in all rats. One group was submitted to the spared nerve injury procedure (SNI) and another to inflammatory pain after carrageenan injection into a hind paw. All animals were tested for hypersensitivity to normally innocuous tactile and thermal stimuli. One group of normal healthy rats was submitted to acute nociceptive (pinch, heat) pain. Microrecording of afferent activity in the gracile nucleus (GN) was performed in a group of nerve-lesioned rats responding to conventional SCS.
  
  
  RESULTS
  HF-SCS at 500, 1,000, or 10,000 Hz at subparesthetic amplitudes produced similar reductions in hypersensitivity due to nerve lesion as did conventional SCS at 50 Hz. HF-SCS showed no effect on thermal pain. A trial to rescue non-responders to conventional SCS using HF-SCS was not successful. There were no effects either of conventional or of HF-SCS on acute or inflammatory pain. Conventional SCS produced massive activation in the GN but no activation during HF-SCS, though normal peripherally evoked afferent activity remained.
  
  
  CONCLUSIONS
  Conventional SCS proved equally effective to HF-SCS in various pain models. As no activity is conveyed rostrally in subparesthetic HF-SCS, we hypothesize that its mechanisms of action are primarily segmental.
authors.affiliation: Department of Clinical Neuroscience, Section of Neurosurgery, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Zhiyang
authors.initials: Z
authors.lastname: Song
authors.forename: Hanna
authors.initials: H
authors.lastname: Viisanen
authors.forename: Björn A
authors.initials: BA
authors.lastname: Meyerson
authors.forename: Antti
authors.initials: A
authors.lastname: Pertovaara
authors.forename: Bengt
authors.initials: B
authors.lastname: Linderoth
mesh_terms: D000344:Afferent Pathways / Q000503:physiopathology; D000818:Animals; D002351:Carrageenan / Q000633:toxicity; D003080:Cold Temperature / Q000009:adverse effects; D003714:Denervation; D004195:Disease Models, Animal; D004567:Electrodes, Implanted; D005528:Foot; D006358:Hot Temperature / Q000009:adverse effects; D006930:Hyperalgesia / Q000139:chemically induced / Q000628:therapy; D007249:Inflammation / Q000503:physiopathology; D008297:Male; D008526:Medulla Oblongata / Q000503:physiopathology; D008839:Microelectrodes; D010146:Pain / Q000145:classification / Q000209:etiology / Q000503:physiopathology*; D059408:Pain Management / Q000379:methods*; D011312:Pressure / Q000009:adverse effects; D051381:Rats; D017208:Rats, Wistar; D012584:Sciatic Nerve / Q000503:physiopathology / Q000601:surgery; D066148:Spinal Cord Dorsal Horn / Q000503:physiopathology; D062187:Spinal Cord Stimulation / Q000379:methods*
chemical_list: D002351:Carrageenan
keywords: Acute nociceptive pain; dorsal column nuclei; inflammatory pain; kilohertz frequencies; neuropathic pain; rat models; spinal cord stimulation