title: Pain relief through an antinociceptive effect after radiofrequency application.
abstract: BACKGROUND
  Many patients with chronic tendinosis have experienced early pain relief after application of bipolar radiofrequency treatment. Pathologic nerve ingrowth or nerve irritation in the tendon has been considered as a possible cause of the pain experienced with tendinosis.
  
  
  OBJECTIVE
  Bipolar radiofrequency treatment will ablate nerve fibers, resulting in pain relief.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  Eighteen Sprague-Dawley rats were used in this study. Eight rats were treated with 2 points of bipolar radiofrequency applications applied to the hind paws with the Topaz microdebrider device, 6 sham rats had a needle applied to the hind paws, and there were 4 control rats. Tissues were processed for neural class III beta-tubulin (TUJ-1) or calcitonin gene-related peptide (CGRP) immunohistochemistry by using the free-floating avidin-biotin complex technique. The numbers of TUJ1-immunoreactive and CGRP-immunoreactive nerve fibers in the epidermis were counted and compared with sham and control.
  
  
  RESULTS
  The number of nerve fibers demonstrated by both the antibodies of TUJ1 and CGRP were significantly decreased (P = .0002-.002) during the first 2 weeks after bipolar radiofrequency treatment. Macroscopically, the foot pad showed 2 dimples on the surface after bipolar radiofrequency treatment. Although it still showed a scar after 7 days, after 14 days it looked no different than the untreated contralateral control foot pad and foot pad of the sham group.
  
  
  CONCLUSIONS
  Bipolar radiofrequency treatment induced acute degeneration and/or ablation of sensory nerve fibers.
  
  
  CONCLUSIONS
  Degeneration or ablation of nerve fibers after bipolar radiofrequency treatment may explain the early postoperative pain relief after microtenotomy for tendinosis.
authors.affiliation: Department of Orthopedic Surgery, University of California, San Diego, La Jolla, California 92093-0630, USA.
authors.forename: Norimasa
authors.initials: N
authors.lastname: Takahashi
authors.forename: James P
authors.initials: JP
authors.lastname: Tasto
authors.forename: Mark
authors.initials: M
authors.lastname: Ritter
authors.forename: Nobuyasu
authors.initials: N
authors.lastname: Ochiai
authors.forename: Seiji
authors.initials: S
authors.lastname: Ohtori
authors.forename: Hideshige
authors.initials: H
authors.lastname: Moriya
authors.forename: David
authors.initials: D
authors.lastname: Amiel
mesh_terms: D000818:Animals; D015740:Calcitonin Gene-Related Peptide; D017115:Catheter Ablation; D008297:Male; D009412:Nerve Fibers; D009475:Neurons, Afferent; D009479:Neuropeptides; D009619:Nociceptors; D010146:Pain; D010149:Postoperative Pain / Q000532:radiotherapy*; D051381:Rats; D017207:Rats, Sprague-Dawley; D052256:Tendinopathy
chemical_list: D009479:Neuropeptides; D015740:Calcitonin Gene-Related Peptide