title: Intraoperative tractography and motor evoked potential (MEP) monitoring in surgery for gliomas around the corticospinal tract.
abstract: BACKGROUND
  Our goal is to indicate the importance of combining intraoperative tractography with motor-evoked potential (MEP) monitoring for glioma surgery in motor eloquent areas.
  
  
  METHODS
  Tumor removal was performed in 28 patients with gliomas in and around the corticospinal tract (CST), in an operation theater equipped with an integrated high-field intraoperative magnetic resonance imaging and a neuronavigation system. Diffusion-tensor imaging-based tractography of the CST was implemented preoperatively and intraoperatively. When the surgically manipulated area came close to the corticospinal pathway, MEP responses were elicited by subcortical stimulation. Responsive areas were compared with the locations of fibers traced by preoperative and intraoperative tractography. Imaging and functional outcomes were reviewed.
  
  
  RESULTS
  Intraoperative tractography demonstrated significant inward or outward shift during surgery. MEP responses were observed around the tract at various intensities, and the distance between MEP responsive sites and intraoperative tractography was significantly correlated with the stimulation intensity (P < 0.01). The distance from preoperative tractography was not correlated. A more than subtotal resection was achieved in 24 patients (85.7%). Transient motor deterioration was seen in 12 patients (42.8%), and a permanent deficit was seen in 1 patient (3.5%).
  
  
  CONCLUSIONS
  We found that intraoperative tractography demonstrated the location of the CST more accurately than preoperative tractography. The results of the linear regression between distance and stimulation intensity were informative for guiding approaches to tumor remnants without impinging on the CST. The combination of intraoperative tractography and MEP monitoring can enhance the quality of surgery for gliomas in motor eloquent areas.
authors.affiliation: Department of Neurosurgery, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan. smaesawa@med.nagoya-u.ac.jp
authors.forename: Satoshi
authors.initials: S
authors.lastname: Maesawa
authors.forename: Masazumi
authors.initials: M
authors.lastname: Fujii
authors.forename: Norimoto
authors.initials: N
authors.lastname: Nakahara
authors.forename: Tadashi
authors.initials: T
authors.lastname: Watanabe
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Wakabayashi
authors.forename: Jun
authors.initials: J
authors.lastname: Yoshida
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000503:physiopathology / Q000601:surgery*; D002540:Cerebral Cortex / Q000503:physiopathology / Q000601:surgery*; D002544:Cerebral Infarction / Q000209:etiology / Q000503:physiopathology; D003399:Craniotomy; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005073:Evoked Potentials, Somatosensory / Q000502:physiology; D005260:Female; D005909:Glioblastoma / Q000503:physiopathology / Q000601:surgery*; D005910:Glioma / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008297:Male; D008866:Microsurgery; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D038361:Neuronavigation; D010291:Paresis / Q000209:etiology / Q000503:physiopathology; D011183:Postoperative Complications / Q000209:etiology / Q000503:physiopathology; D011712:Pyramidal Tracts / Q000503:physiopathology / Q000601:surgery*; D012680:Sensitivity and Specificity; D055815:Young Adult