title: Application of pulsed radiofrequency currents to rat dorsal root ganglia modulates nerve injury-induced tactile allodynia.
abstract: BACKGROUND
  Application of pulsed radiofrequency (PRF) currents to the dorsal root ganglia (DRG) has been reported to produce relief from certain pain states without causing thermal ablation. In this study, we examined the direct correlation between PRF application to DRG associated with spinal nerve injury and reversal of injury-induced behavioral hypersensitivity in a rat neuropathic pain model.
  
  
  METHODS
  Neuropathic lesioning was performed via left L5 spinal nerve ligation on male adult Sprague-Dawley rats. Once the injured rats had developed tactile allodynia, one group was then assigned to PRF treatment of the L5 DRG and another group was assigned to the sham treatment to the DRG. Behavioral testing was performed on both the control and treated paws using the von Frey filament test before the surgery and at indicated days. The resulting data were analyzed using a linear mixed model to assess the overall difference between the treatment groups and the overall difference among the study days. Cohen's d statistic was computed from paired difference-from-baseline scores for each of the 14 study days after treatment and these measures of effect size were then used to descriptively compare the recovery patterns over time for each study group.
  
  
  RESULTS
  Spinal nerve injury resulted in the development of behavioral hypersensitivity to von Frey filament stimulation (allodynia) in the hindpaw of the left (injury) side. Mixed linear modeling showed a significant difference between the treatment groups (P = 0.0079) and a significant change of paw withdrawal threshold means over time (P = 0.0006) for all 12 animals. Evaluation of Cohen's d (effect size) revealed that the PRF-treated animals exhibited better recovery and recorded larger effect sizes than the sham-treated animals on 10 of the 14 post-PRF treatment days and exhibited moderate-to-strong effects posttreatment at days 8 to 10 and at and beyond day 32.
  
  
  CONCLUSIONS
  Findings from this study support that PRF of the DRG causes reversal of nerve injury (spinal nerve ligation)-induced tactile allodynia in rats. This allodynia reversal indicates that nonablative PRF acting via modulation of the DRG can speed recovery in nerve injury-induced pain.
authors: Department of Anesthesiology & Perioperative Care, University of California, 101 The City Drive South, Orange, CA 92868, USA.
authors: Danielle M
authors: DM
authors: Perret
authors: Doo-Sik
authors: DS
authors: Kim
authors: Kang-Wu
authors: KW
authors: Li
authors: Karin
authors: K
authors: Sinavsky
authors: Robert L
authors: RL
authors: Newcomb
authors: Jason M
authors: JM
authors: Miller
authors: Z David
authors: ZD
authors: Luo
references: Neurosurgery. 2002 Apr;50(4):850-5; discussion 856
references: 11904038
references: Pain Pract. 2003 Sep;3(3):232-7
references: 17147673
references: Surg Neurol. 1974 Sep;2(5):319-25
references: 4853577
references: Bioelectromagnetics. 2003 Apr;24(3):174-81
references: 12669300
references: Pain. 2007 Jan;127(1-2):173-82
references: 17055165
references: Reg Anesth Pain Med. 2010 Jan-Feb;35(1):11-5
references: 20048653
references: Pain. 1999 Mar;80(1-2):437-9
references: 10204759
references: Pain Physician. 2009 May-Jun;12(3):633-8
references: 19461829
references: Curr Rev Pain. 2000;4(1):49-53
references: 10998715
references: Pain. 2004 Apr;108(3):297-298
references: 15030950
references: Pain Pract. 2009 Nov-Dec;9(6):407-17
references: 19761513
references: Pain. 2009 May;143(1-2):114-22
references: 19307059
references: Pain. 1992 Sep;50(3):355-363
references: 1333581
references: Pain Physician. 2008 Mar-Apr;11(2):137-44
references: 18354708
references: Pain Med. 2009 May-Jun;10(4):673-8
references: 19302438
references: Mt Sinai J Med. 2006 Jul;73(4):716-8
references: 16878278
references: Pain. 1977 Feb;3(1):25-41
references: 195255
references: Surg Neurol. 2009 Nov;72(5):496-500; discussion 501
references: 19329170
references: Anesthesiology. 2008 Sep;109(3):527-42
references: 18719452
references: Reg Anesth Pain Med. 2006 Mar-Apr;31(2):152-67
references: 16543102
references: Urology. 2003 Mar;61(3):645
references: 12639676
references: J Neurosci Methods. 1994 Jul;53(1):55-63
references: 7990513
references: Pain Physician. 2006 Jul;9(3):227-35
references: 16886031
references: J Pain. 2003 May;4(4):197-202
references: 14622704
references: Surg Neurol. 2008 Dec;70 Suppl 1:S1:50-5; discussion S1:55
references: 18786711
references: Pain Pract. 2008 Sep-Oct;8(5):385-93
references: 18721175
references: Spine (Phila Pa 1976). 2005 May 1;30(9):1008-13
references: 15864151
references: Agri. 2009 Jan;21(1):16-21
references: 19357996
references: Pain Med. 2006 Sep-Oct;7(5):453-6
references: 17014606
references: J Clin Anesth. 2008 Nov;20(7):534-7
references: 19041042
references: Eur J Pain. 2006 Feb;10(2):171-6
references: 16310722
references: Clin J Pain. 2007 Jul-Aug;23(6):524-9
references: 17575493
references: Surg Neurol. 2008 Jul;70(1):59-65; discussion 65
references: 18207554
references: Pain Pract. 2004 Dec;4(4):310-3
references: 17173614
references: Pain. 2003 Aug;104(3):449-452
references: 12927617
references: Trends Neurosci. 2003 Dec;26(12):696-705
references: 14624855
references: J Neurosci. 2001 Mar 15;21(6):1868-75
references: 11245671
references: Anesthesiology. 2006 Jun;104(6):1283-92
references: 16732101
references: Clin J Pain. 2008 Oct;24(8):736-9
references: 18806541
references: Pain. 1983 Dec;17(4):321-339
references: 6664680
references: J Neurochem. 2003 Nov;87(3):560-73
references: 14535940
references: Eur Spine J. 2009 Apr;18(4):473-8
references: 19172311
references: Anesth Analg. 2008 Oct;107(4):1406-11
references: 18806060
references: Anesthesiology. 2005 Jan;102(1):125-31
references: 15618796