title: Contribution of combined intraoperative electrophysiological investigation with 3-T intraoperative MRI for awake cerebral glioma surgery: comprehensive review of the clinical implications and radiological outcomes.
abstract: OBJECTIVE
  This study aimed to assess the clinical efficiency of combined awake craniotomy with 3-T intraoperative MRI (iMRI)-guided resection of gliomas adjacent to eloquent cortex performed at a single center. It also sought to explore the contribution of iMRI to surgeons' learning process of maximal safe resection of gliomas.
  
  
  METHODS
  All patients who underwent an awake craniotomy and iMRI for resection of eloquent area glioma during the 53 months between January 2011 and June 2015 were included. The cases were analyzed for short- and long-term neurological outcome, progression-free survival (PFS), overall survival (OS), and extent of resection (EOR). The learning curve was assessed after dividing the cohort into Group A (first 27 months) and Group B (last 26 months). Statistical analyses included univariate logistic regression analysis on clinical and radiological variables. Kaplan-Meier and Cox regression models were used for further analysis of OS and PFS. A p value < 0.05 was considered statistically significant.
  
  
  RESULTS
  One hundred six patients were included in the study. Over an average follow-up period of 24.8 months, short- and long-term worsening of the neurological function was noted in 48 (46.2%) and 9 (8.7%) cases, respectively. The median and mean EOR were 100% and 92%, respectively, and complete radiographic resection was achieved in 64 (60.4%) patients. The rate of gross-total resection (GTR) in the patients with low-grade glioma (89.06% ± 19.6%) was significantly lower than that in patients with high-grade glioma (96.4% ± 9.1%) (p = 0.026). Thirty (28.3%) patients underwent further resection after initial iMRI scanning, with a 10.1% increase of the mean EOR. Multivariate Cox proportional hazards modeling demonstrated that the final EOR was a significant predictor of PFS (HR 0.225, 95% CI 0.070-0.723, p = 0.012). For patients with high-grade glioma, the GTR (p = 0.033), the presence of short-term motor deficit (p = 0.027), and the WHO grade (p = 0.005) were independent prognostic factors of OS. Performing further resection after the iMRI (p = 0.083) and achieving GTR (p = 0.05) demonstrated a PFS benefit trend for the patients affected by a low-grade glioma. Over time, the rate of performing further resection after an iMRI decreased by 26.1% (p = 0.005). A nonsignificant decrease in the rate of short-term (p = 0.101) and long-term (p = 0.132) neurological deficits was equally noted.
  
  
  CONCLUSIONS
  Combined awake craniotomy and iMRI is a safe and efficient technique allowing maximal safe resection of eloquent area gliomas with possible subsequent OS and PFS benefits. Although there is a learning curve for applying this technique, it can also improve the surgeon's ability in eloquent glioma surgery.
authors.affiliation: Glioma Surgery Division, Department of Neurosurgery, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China; and.|Department of Neurosurgery, The Ottawa Hospital, University of Ottawa, Ontario, Canada.
authors.forename: Diana
authors.initials: D
authors.lastname: Ghinda
authors.affiliation: Glioma Surgery Division, Department of Neurosurgery, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China; and.
authors.forename: Nan
authors.initials: N
authors.lastname: Zhang
authors.affiliation: Glioma Surgery Division, Department of Neurosurgery, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China; and.
authors.forename: Junfeng
authors.initials: J
authors.lastname: Lu
authors.affiliation: Glioma Surgery Division, Department of Neurosurgery, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China; and.
authors.forename: Cheng-Jun
authors.initials: CJ
authors.lastname: Yao
authors.affiliation: Glioma Surgery Division, Department of Neurosurgery, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China; and.
authors.forename: Shiwen
authors.initials: S
authors.lastname: Yuan
authors.affiliation: Glioma Surgery Division, Department of Neurosurgery, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China; and.
authors.forename: Jin-Song
authors.initials: JS
authors.lastname: Wu
mesh_terms: D000328:Adult; D003131:Combined Modality Therapy / Q000379:methods; D003399:Craniotomy / Q000379:methods*; D004558:Electric Stimulation / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D005910:Glioma / Q000000981:diagnostic imaging* / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D015173:Supratentorial Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery*; D014851:Wakefulness
keywords: BOLD = blood oxygen level dependent; DTI = diffusion tensor imaging; EOR = extent of resection; GTR = gross-total resection; HGG = high-grade glioma; LGG = low-grade glioma; MEP = motor evoked potential; OS = overall survival; PFS = progression-free survival; QOL = quality of life; awake craniotomy; clinical outcome; eloquent areas; extent of resection; glioma; iMRI = intraoperative MRI; intraoperative MRI; intraoperative neurophysiological monitoring; quality of life; survival