title: Gross total resection rates of grade II/III intramedullary ependymomas using the surgical strategy of en-bloc resection without intra-operative neurophysiological monitoring.
abstract: BACKGROUND
  Grade II and III intramedullary ependymomas [IME] are circumscribed with a plane of cleavage that should facilitate high gross total resection rates (GTR). Gross total resection of grade II/III IME is superior to subtotal resection (STR) and radiotherapy (RTx) for progression-free and overall survival. We sought to compare our GTR with other series that have utilised standard intraoperative monitoring techniques and we explored factors that may influence rates of resection.
  
  
  METHODS
  Database search and retrospective chart and radiological review of all grade II or III spinal ependymomas over a 10-year period from the senior authors practice. Comprehensive PubMed search to identify similar series that identified histology, McCormick Function scores (MCC) preoperatively and post-operatively, surgical strategy and use of intraoperative monitoring. Standard statistical analysis was performed.
  
  
  RESULTS
  Seventeen patients were identified: 16 grade II and one grade 3. GTR was 94.12%. Factors that correlated with a decline in MCC were longitudinal extension of the tumour (p = 0.0238) and presentation with motor signs and symptoms (p = 0.0223). There was no statistical difference between preoperative factors that influence post-operative outcomes in the current study when compared with other published series. There was no statistical difference between preoperative and postoperative MCC scores between our series and other published series.
  
  
  CONCLUSIONS
  The current series with a GTR of 94.12% compares favourably with other published series with GTRs of 55.8-84% with no significant difference in functional outcomes. Series with low GTRs should examine their operative strategy or false-positive alarm rates which may lead to higher STRs. This series should be viewed as a unique opportunity to benchmark GTRs of circumscribed intramedullary tumours.
authors.affiliation: a Beaumont Hospital , The National Centre for Neurosurgery , Ireland.
authors.forename: Kieron J
authors.initials: KJ
authors.lastname: Sweeney
authors.affiliation: b Department of Neurological Surgery , Washington University Medical School.
authors.forename: Matt
authors.initials: M
authors.lastname: Reynolds
authors.affiliation: c Department of Neuropathology , Beaumont Hospital , Ireland.
authors.forename: Michael
authors.initials: M
authors.lastname: Farrell
authors.affiliation: a Beaumont Hospital , The National Centre for Neurosurgery , Ireland.
authors.forename: Ciaran
authors.initials: C
authors.lastname: Bolger
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D019985:Benchmarking; D001699:Biometry; D016208:Databases, Factual; D018450:Disease Progression; D004806:Ependymoma / Q000473:pathology / Q000601:surgery*; D005260:Female; D006801:Humans; D064795:Intraoperative Neurophysiological Monitoring / Q000379:methods; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013120:Spinal Cord Neoplasms / Q000473:pathology / Q000601:surgery*; D016896:Treatment Outcome; D055815:Young Adult
keywords: En bloc resection; ependymoma; intramedullary spinal cord tumours; intraoperative monitoring