title: Local anesthetic sympathectomy restores fMRI cortical maps in CRPS I after upper extremity stellate blockade: a prospective case study.
abstract: BACKGROUND
  Patients with complex regional pain syndrome type I (CRPS I) show a cortical reorganization with contralateral shrinkage of cortical maps in S1. The relevance of pain and disuse for the development and the maintenance of this shrinkage is unclear.
  
  
  OBJECTIVE
  Aim of the study was to assess whether short-term pain relief induces changes in the cortical representation of the affected hand in patients with CRPS type I.
  
  
  METHODS
  Case series analysis of prospectively collected data.
  
  
  METHODS
  We enrolled a case series of 5 consecutive patients with CRPS type I (disease duration 3 - 36 months) of the non-dominant upper-limb and previously diagnosed sympathetically maintained pain (SMP) by reduction of the pain intensity of more than > 30% after prior diagnostic sympathetic block. We performed fMRI for analysis of the cortical representation of the affected hand immediately before as well as one hour after isolated sympathetic block of the stellate ganglion on the affected side.
  
  
  METHODS
  Wilcoxon-Test, paired t-test, P < 0.05.
  
  
  RESULTS
  Pain decrease after isolated sympathetic block (pain intensity on the numerical rating scale (0 - 10) before block: 6.8 ± 1.9, afterwards: 3.8 ± 1.3) was accompanied by an increase in the blood oxygenation level dependent (BOLD) response of cortical representational maps only of the affected hand which had been reduced before the block, despite the fact that clinical and neurophysiological assessment revealed no changes in the sensorimotor function.
  
  
  CONCLUSIONS
  The interpretation of the present results is partly limited due to the small number of included patients and the missing control group with placebo injection.
  
  
  CONCLUSIONS
  The association between recovery of the cortical representation and pain relief supports the hypothesis that pain could be a relevant factor for changes of somatosensory cortical maps in CRPS, and that these are rapidly reversible.
authors.forename: Philipp
authors.initials: P
authors.lastname: Stude
authors.affiliation: Department of Neurology, BG University Hospital Bergmannsheil GmbH, Ruhr University Bochum, Germany; Department for Diagnostic and Interventional Radiology and Nuclear Medicine, BG University Hospital Bergmannsheil GmbH, Ruhr University Bochum, Germany; D.
authors.forename: Elena K
authors.initials: EK
authors.lastname: Enax-Krumova
authors.forename: Melanie
authors.initials: M
authors.lastname: Lenz
authors.forename: Silke
authors.initials: S
authors.lastname: Lissek
authors.forename: Volkmar
authors.initials: V
authors.lastname: Nicolas
authors.forename: Soeren
authors.initials: S
authors.lastname: Peters
authors.forename: Amy
authors.initials: A
authors.lastname: Westermann
authors.forename: Martin
authors.initials: M
authors.lastname: Tegenthoff
authors.forename: Christoph
authors.initials: C
authors.lastname: Maier
mesh_terms: D000328:Adult; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000494:pharmacology*; D001340:Autonomic Nerve Block / Q000379:methods; D001931:Brain Mapping; D002045:Bupivacaine / Q000008:administration & dosage / Q000494:pharmacology; D005260:Female; D006225:Hand / Q000503:physiopathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D012019:Reflex Sympathetic Dystrophy / Q000188:drug therapy* / Q000503:physiopathology*; D013003:Somatosensory Cortex / Q000503:physiopathology*; D013562:Sympathectomy / Q000379:methods*; D055815:Young Adult
chemical_list: D000779:Anesthetics, Local; D002045:Bupivacaine