title: Low-grade Glioma Surgery in Intraoperative Magnetic Resonance Imaging: Results of a Multicenter Retrospective Assessment of the German Study Group for Intraoperative Magnetic Resonance Imaging.
abstract: The ideal treatment strategy for low-grade gliomas (LGGs) is a controversial topic. Additionally, only smaller single-center series dealing with the concept of intraoperative magnetic resonance imaging (iMRI) have been published.
  
  
  
  To investigate determinants for patient outcome and progression-free-survival (PFS) after iMRI-guided surgery for LGGs in a multicenter retrospective study initiated by the German Study Group for Intraoperative Magnetic Resonance Imaging.
  
  
  
  A retrospective consecutive assessment of patients treated for LGGs (World Health Organization grade II) with iMRI-guided resection at 6 neurosurgical centers was performed. Eloquent location, extent of resection, first-line adjuvant treatment, neurophysiological monitoring, awake brain surgery, intraoperative ultrasound, and field-strength of iMRI were analyzed, as well as progression-free survival (PFS), new permanent neurological deficits, and complications. Multivariate binary logistic and Cox regression models were calculated to evaluate determinants of PFS, gross total resection (GTR), and adjuvant treatment.
  
  
  
  A total of 288 patients met the inclusion criteria. On multivariate analysis, GTR significantly increased PFS (hazard ratio, 0.44; P < .01), whereas "failed" GTR did not differ significantly from intended subtotal-resection. Combined radiochemotherapy as adjuvant therapy was a negative prognostic factor (hazard ratio: 2.84, P < .01). Field strength of iMRI was not associated with PFS. In the binary logistic regression model, use of high-field iMRI (odds ratio: 0.51, P < .01) was positively and eloquent location (odds ratio: 1.99, P < .01) was negatively associated with GTR. GTR was not associated with increased rates of new permanent neurological deficits.
  
  
  
  GTR was an independent positive prognostic factor for PFS in LGG surgery. Patients with accidentally left tumor remnants showed a similar prognosis compared with patients harboring only partially resectable tumors. Use of high-field iMRI was significantly associated with GTR. However, the field strength of iMRI did not affect PFS.
  
  
  
  EoR, extent of resectionFLAIR, fluid-attenuated inversion recoveryGTR, gross total resectionIDH1, isocitrate dehydrogenase 1iMRI, intraoperative magnetic resonance imagingLGG, low-grade gliomaMGMT, methylguanine-deoxyribonucleic acid methyltransferasenPND, new permanent neurological deficitOS, overall survivalPFS, progression-free survivalSTR, subtotal resectionWHO, World Health Organization.
authors.affiliation: ‡Department of Neurosurgery, University of Ulm, Günzburg, Germany; §Department of Neurosurgery, University of Erlangen, Erlangen, Germany; ¶Department of Neurosurgery, University of Heidelberg, Heidelberg, Germany; ‖Department of Neurosurgery, University of Schleswig-Holstein, Kiel, Germany; #Department of Neurosurgery, University of Frankfurt, Frankfurt, Germany; **Department of Neurosurgery, University of Tübingen, Tübingen, Germany; ‡‡Department of Internal Medicine III, University of Ulm, Ulm, Germany; §§Institute for Epidemiology and Medical Biometrics, University of Ulm, Ulm, Germany; ¶¶Department of Neuroradiology, University of Tübingen, Tübingen, Germany; ‖‖Department of Neurosurgery, International Neuroscience Institute Hannover, Hannover, Germany; ##Department of Neurosurgery, Klinikum Stuttgart, Stuttgart, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Coburger
authors.forename: Andreas
authors.initials: A
authors.lastname: Merkel
authors.forename: Moritz
authors.initials: M
authors.lastname: Scherer
authors.forename: Felix
authors.initials: F
authors.lastname: Schwartz
authors.forename: Florian
authors.initials: F
authors.lastname: Gessler
authors.forename: Constantin
authors.initials: C
authors.lastname: Roder
authors.forename: Andrej
authors.initials: A
authors.lastname: Pala
authors.forename: Ralph
authors.initials: R
authors.lastname: König
authors.forename: Lars
authors.initials: L
authors.lastname: Bullinger
authors.forename: Gabriele
authors.initials: G
authors.lastname: Nagel
authors.forename: Christine
authors.initials: C
authors.lastname: Jungk
authors.forename: Sotirios
authors.initials: S
authors.lastname: Bisdas
authors.forename: Arya
authors.initials: A
authors.lastname: Nabavi
authors.forename: Oliver
authors.initials: O
authors.lastname: Ganslandt
authors.forename: Volker
authors.initials: V
authors.lastname: Seifert
authors.forename: Marcos
authors.initials: M
authors.lastname: Tatagiba
authors.forename: Christian
authors.initials: C
authors.lastname: Senft
authors.forename: Maximilian
authors.initials: M
authors.lastname: Mehdorn
authors.forename: Andreas W
authors.initials: AW
authors.lastname: Unterberg
authors.forename: Karl
authors.initials: K
authors.lastname: Rössler
authors.forename: Christian Rainer
authors.initials: CR
authors.lastname: Wirtz
mesh_terms: D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000401:mortality / Q000601:surgery*; D018572:Disease-Free Survival; D005260:Female; D005910:Glioma / Q000000981:diagnostic imaging* / Q000401:mortality / Q000601:surgery*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods; D064926:Neurophysiological Monitoring / Q000379:methods; D012189:Retrospective Studies; D025321:Surgery, Computer-Assisted / Q000379:methods*