title: High-frequency electrical nerve block for postamputation pain: a pilot study.
abstract: OBJECTIVE
  This study aimed to assess the analgesic effect of kilohertz alternating current applied to the severed nerves in amputees afflicted by intractable limb pain.
  
  
  METHODS
  Ten lower-limb amputees with chronic and severe residual limb pain or phantom limb pain who attained significant pain reduction after local nerve block injection were enrolled. A cuff electrode was wrapped around the sciatic or tibial nerve. An external waveform generator was used for the main part of the study, while an implantable generator was developed and implanted in the responders after 9 to 12 months. Sinusoidal waveforms of 10 kHz and up to 10 V were applied for 30 min during each subject-initiated treatment session. A diary was used to record pain intensities before and after each session.
  
  
  RESULTS
  Among the seven subjects who received treatment, the average pain reduction was 75% at the three-month primary end point. These subjects were responders per predefined criterion of achieving ≥50% pain reduction in ≥50% of treatment sessions for the three-month end point. Pain medication use and interference of pain on functions was significantly reduced. The treatment efficacy was sustained through the follow-up period of up to 12 months. Besides dislodgement and loss of function for one electrode in one subject, all other devices functioned as intended. No changes of residual motor and sensory function were observed.
  
  
  CONCLUSIONS
  This pilot study generated preliminary evidence on the efficacy and safety of kilohertz electrical nerve block for postamputation pain, justifying a pivotal study for regulatory approval.
authors: Ohio Pain Clinic, Dayton, OH, USA.
authors: Amol
authors: A
authors: Soin
authors: Nemath Syed
authors: NS
authors: Shah
authors: Zi-Ping
authors: ZP
authors: Fang
mesh_terms: D000368:Aged; D000672:Amputation Stumps / Q000503:physiopathology*; D001703:Biophysics; D004599:Electric Stimulation Therapy / Q000379:methods*; D004567:Electrodes, Implanted; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009407:Nerve Block / Q000379:methods*; D010149:Postoperative Pain / Q000628:therapy*; D010525:Peripheral Nerves / Q000502:physiology*; D010865:Pilot Projects; D016896:Treatment Outcome
keywords: Neuromodulation; peripheral nerve; phantom pain; residual limb pain; sciatic nerve; stump pain; tibial nerve