title: Cerebrospinal fluid levels of vascular endothelial growth factor correlate with reported pain and are reduced by spinal cord stimulation in patients with failed back surgery syndrome.
abstract: OBJECTIVE
  Spinal cord stimulation (SCS) is an efficacious therapy for chronic neuropathic pain whose precise mechanism of action is unclear. Mediators produced by glial and immune cells are now believed to modulate neuronal transmission and promote chronic neuropathic pain. We postulated a relationship between cerebrospinal fluid (CSF) concentrations of neuroimmune mediators and SCS.
  
  
  METHODS
  We measured CSF concentrations of the chemokine, monocyte chemotactic protein-1 (MCP-1), and the growth factors, brain-derived neurotrophic factor (BDNF), and vascular endothelial growth factor (VEGF) and tested for relationships with stimulation parameters and clinical response in nine patients with failed back surgery syndrome (FBSS).
  
  
  RESULTS
  Patients with FBSS had higher CSF concentrations of BDNF (p = 0.01) and MCP-1 (p = 0.0001) than matched controls. CSF concentrations of BDNF and VEGF correlated with reported pain (p = 0.04). Five minutes of SCS resulted in a reduction in median VEGF concentrations (p = 0.01).
  
  
  CONCLUSIONS
  Patients with FBSS have altered CSF levels of BDNF and MCP-1. CSF VEGF correlates with pain and is reduced by SCS. This may offer novel insights into both the mechanism of action of SCS in FBSS and the variation in clinical response that may be encountered.
authors.affiliation: Department of Pain Medicine, St James's Hospital, Dublin, Ireland.
authors.forename: Kevin F
authors.initials: KF
authors.lastname: McCarthy
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Connor
authors.forename: Connail
authors.initials: C
authors.lastname: McCrory
mesh_terms: D000328:Adult; D000368:Aged; D019208:Brain-Derived Neurotrophic Factor / Q000134:cerebrospinal fluid; D018932:Chemokine CCL2 / Q000134:cerebrospinal fluid; D018925:Chemokines / Q000134:cerebrospinal fluid; D055111:Failed Back Surgery Syndrome / Q000134:cerebrospinal fluid* / Q000150:complications / Q000628:therapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009437:Neuralgia / Q000134:cerebrospinal fluid* / Q000209:etiology / Q000628:therapy*; D010147:Pain Measurement; D062187:Spinal Cord Stimulation; D016896:Treatment Outcome; D042461:Vascular Endothelial Growth Factor A / Q000134:cerebrospinal fluid*
chemical_list: D019208:Brain-Derived Neurotrophic Factor; C111835:CCL2 protein, human; D018932:Chemokine CCL2; D018925:Chemokines; D042461:Vascular Endothelial Growth Factor A
keywords: basic science; failed back surgery syndrome; mechanisms of action; nonrandomized study; prospective; spinal cord stimulation