title: Integration of functional neuronavigation and intraoperative MRI in surgery for drug-resistant extratemporal epilepsy close to eloquent brain areas.
abstract: OBJECTIVE
  The authors performed a retrospective study to assess the impact of functional neuronavigation and intraoperative MRI (iMRI) on surgery of extratemporal epileptogenic lesions on postsurgical morbidity and seizure control.
  
  
  METHODS
  Twenty-five patients (14 females and 11 males) underwent extratemporal resections for drug-resistant epilepsy close to speech/motor brain areas or adjacent to white matter tracts. The mean age at surgery was 34 years (range 12-67 years). The preoperative mean disease duration was 13.2 years. To avoid awake craniotomy, cortical motor-sensory representation was mapped during preoperative evaluation in 14 patients and speech representation was mapped in 15 patients using functional MRI. In addition, visualization of the pyramidal tract was performed in 11 patients, of the arcuate fascicle in 7 patients, and of the visual tract in 6 patients using diffusion tensor imaging. The mean minimum distance of tailored resection between the eloquent brain areas was 5.6 mm. During surgery, blood oxygen level-dependent imaging and diffusion tensor imaging data were integrated into neuronavigation and displayed through the operating microscope. The postoperative mean follow-up was 44.2 months.
  
  
  RESULTS
  In 20% of these patients, further intraoperative resection was performed because of intraoperatively documented residual lesions according to iMRI findings. At the end of resection, the final iMRI scans confirmed achievement of total resection of the putative epileptogenic lesion in all patients. Postoperatively, transient complications and permanent complications were observed in 20% and 12% of patients, respectively. Favorable postoperative seizure control (Engel Classes I and II) was achieved in 84% and seizure freedom in 72% of these consecutive surgical patients.
  
  
  CONCLUSIONS
  By using functional neuronavigation and iMRI for treatment of epileptogenic brain lesions, the authors achieved a maximum extent of resection despite the lesions' proximity to eloquent brain cortex and fiber tracts in all cases. The authors' results underline possible benefits of this technique leading to a favorable seizure outcome with acceptable neurological deficit rates in difficult-to-treat extratemporal epilepsy.
authors.affiliation: Department of Neurosurgery, University Hospital Erlangen, Erlangen 91054, Germany. bjoern.sommer@uk-erlangen.de
authors.forename: Björn
authors.initials: B
authors.lastname: Sommer
authors.forename: Peter
authors.initials: P
authors.lastname: Grummich
authors.forename: Roland
authors.initials: R
authors.lastname: Coras
authors.forename: Burkhard Sebastian
authors.initials: BS
authors.lastname: Kasper
authors.forename: Ingmar
authors.initials: I
authors.lastname: Blumcke
authors.forename: Hajo Martinus
authors.initials: HM
authors.lastname: Hamer
authors.forename: Hermann
authors.initials: H
authors.lastname: Stefan
authors.forename: Michael
authors.initials: M
authors.lastname: Buchfelder
authors.forename: Karl
authors.initials: K
authors.lastname: Roessler
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001931:Brain Mapping / Q000379:methods; D002648:Child; D004827:Epilepsy / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D009044:Motor Cortex / Q000502:physiology*; D009413:Nerve Fibers, Myelinated / Q000502:physiology*; D038361:Neuronavigation / Q000379:methods*; D010775:Photic Stimulation / Q000379:methods; D012189:Retrospective Studies; D055815:Young Adult