title: Combination of functional magnetic resonance imaging-guided neuronavigation and intraoperative cortical brain mapping improves targeting of motor cortex stimulation in neuropathic pain.
abstract: OBJECTIVE
  To evaluate, regardless of the clinical results, the contribution of combining functional magnetic resonance imaging (fMRI) with intraoperative cortical brain mapping (iCM) as functional targeting methods for epidural chronic motor cortex stimulation (MCS) in refractory neuropathic pain.
  
  
  METHODS
  Eighteen neuropathic pain patients (central stroke in six; trigeminal neuropathy in six; syrinx or amputation in six) who underwent operations for epidural MCS were studied with preoperative fMRI and iCM. fMRI investigated motor tasks of hands (as well as foot and tongue, when painful). fMRI data were analyzed with Statistical Parametric Mapping99 software (University College London, London, England; initial analysis threshold corresponding to P < 0.001), registered in a neuronavigation system, and correlated during surgery with iCM. The primary aim of this study was to improve the topographical precision of MCS. Matching of fMRI and iCM specifically was examined.
  
  
  RESULTS
  Correspondence between the contour of the fMRI activation area and iCM in precentral gyrus (mean distance, 3.8 mm) was found in 17 (94%) of 18 patients. Eleven of them showed correspondence for more restrictive values of the analysis threshold (P < 0.0001); in six patients, the quality of the iCM was reduced by somatosensory wave attenuation and general anesthesia. In this group of six patients, a combination of both techniques was used for the final targeting. Correspondence was not found in one patient as the result of image distortion and residual motion artifact. At follow-up (4-60 mo), MCS induced significant pain relief in a total of 11 patients (61%).
  
  
  CONCLUSIONS
  This study confirms the functional accuracy of fMRI guidance in neuropathic pain and illustrates the usefulness of combining fMRI guidance with iCM to improve the functional targeting in MCS. Because appropriate targeting is crucial to obtaining pain relief, this combination may increase the analgesic efficacy of MCS.
authors.affiliation: Department of Neurosurgery, Erasme Hospital, Université Libre de Bruxelles, Brussels, Belgium. bpirotte@ulb.ac.be
authors.forename: Benoit
authors.initials: B
authors.lastname: Pirotte
authors.forename: Philippe
authors.initials: P
authors.lastname: Voordecker
authors.forename: Carine
authors.initials: C
authors.lastname: Neugroschl
authors.forename: Danielle
authors.initials: D
authors.lastname: Baleriaux
authors.forename: David
authors.initials: D
authors.lastname: Wikler
authors.forename: Thierry
authors.initials: T
authors.lastname: Metens
authors.forename: Vincent
authors.initials: V
authors.lastname: Denolin
authors.forename: Alfred
authors.initials: A
authors.lastname: Joffroy
authors.forename: Nicolas
authors.initials: N
authors.lastname: Massager
authors.forename: Jacques
authors.initials: J
authors.lastname: Brotchi
authors.forename: Marc
authors.initials: M
authors.lastname: Levivier
mesh_terms: D000328:Adult; D000368:Aged; D001931:Brain Mapping; D004599:Electric Stimulation Therapy / Q000009:adverse effects; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D009044:Motor Cortex / Q000503:physiopathology*; D009437:Neuralgia / Q000503:physiopathology / Q000628:therapy*; D038361:Neuronavigation; D010166:Palliative Care; D012189:Retrospective Studies; D016896:Treatment Outcome