title: Treating intractable phantom limb pain with ambulatory continuous peripheral nerve blocks: a pilot study.
abstract: BACKGROUND
  There is currently no reliable treatment for phantom limb pain (PLP). Chronic PLP and associated cortical abnormalities may be maintained from abnormal peripheral input, raising the possibility that a continuous peripheral nerve block (CPNB) of extended duration may permanently reorganize cortical pain mapping, thus providing lasting relief.
  
  
  METHODS
  Three men with below-the-knee (2) or -elbow (1) amputations and intractable PLP received femoral/sciatic or infraclavicular perineural catheter(s), respectively. Subjects were randomized in a double-masked fashion to receive perineural ropivacaine (0.5%) or normal saline for over 6 days as outpatients using portable electronic infusion pumps. Four months later, subjects returned for repeated perineural catheter insertion and received an ambulatory infusion with the alternate solution ("crossover"). Subjects were followed for up to 1 year.
  
  
  RESULTS
  By chance, all three subjects received saline during their initial infusion and reported little change in their PLP. One subject did not receive crossover treatment, but the remaining two subjects reported complete resolution of their PLP during and immediately following treatment with ropivacaine. One subject experienced no PLP recurrence through the 52-week follow-up period and the other reported mild PLP occurring once each week of just a small fraction of his original pain (pretreatment: continuous PLP rated 10/10; posttreatment: no PLP at baseline with average of one PLP episode each week rated 2/10) for 12 weeks (lost to follow-up thereafter).
  
  
  CONCLUSIONS
  A prolonged ambulatory CPNB may be a reliable treatment for intractable PLP. The results of this pilot study suggest that a large, randomized clinical trial is warranted.
authors.affiliation: Department of Anesthesiology, University of California San Diego, San Diego, California 92103-8770, USA. bilfeld@ucsd.edu
authors.forename: Brian M
authors.initials: BM
authors.lastname: Ilfeld
authors.forename: Tobias
authors.initials: T
authors.lastname: Moeller-Bertram
authors.forename: Steven R
authors.initials: SR
authors.lastname: Hanling
authors.forename: Kyle
authors.initials: K
authors.lastname: Tokarz
authors.forename: Edward R
authors.initials: ER
authors.lastname: Mariano
authors.forename: Vanessa J
authors.initials: VJ
authors.lastname: Loland
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Madison
authors.forename: Eliza J
authors.initials: EJ
authors.lastname: Ferguson
authors.forename: Anya C
authors.initials: AC
authors.lastname: Morgan
authors.forename: Mark S
authors.initials: MS
authors.lastname: Wallace
mesh_terms: D000328:Adult; D000577:Amides / Q000008:administration & dosage*; D000779:Anesthetics, Local / Q000008:administration & dosage; D006801:Humans; D015918:Infusion Pumps, Implantable; D008297:Male; D009407:Nerve Block / Q000379:methods*; D010148:Intractable Pain / Q000188:drug therapy*; D010591:Phantom Limb / Q000188:drug therapy*; D000077212:Ropivacaine; D016896:Treatment Outcome
chemical_list: D000577:Amides; D000779:Anesthetics, Local; D000077212:Ropivacaine