title: World Health Organization Grade I Convexity Meningiomas: Study on Outcomes, Complications and Recurrence Rates.
abstract: BACKGROUND
  The clinical significance of the Simpson grading system of extent of meningioma resection and its role as a predictor for recurrence of World Health Organization (WHO) grade I meningiomas have been questioned in the past, as microsurgery and knowledge of pathologic details have advanced.
  
  
  METHODS
  Clinical and radiologic information on 112 patients with WHO grade I convexity meningiomas who underwent surgery over the past 20 years was retrospectively reviewed.
  
  
  RESULTS
  The recurrence rate in the grade 0-I resection group was 2.9%, whereas in the grade II-IV resection group, the recurrence rate was 31% (P = 0.0001). In Cox regression analysis, Simpson grade 0-I resection was revealed as a significant predictor of recurrence-free survival (P = 0.021). The hazard ratio for recurrence after II-IV resection was 10.98 times higher than grade 0-I. Like the Simpson grading of resection, a similar trend of recurrence (grade I, 1.6% vs. grade II-IV, 28%, P = 0.0001) was observed in the Shinshu grade of resection. In univariate analysis, female gender and use of neuronavigation were also identified as independent predictors of recurrence-free survival after resection of WHO grade I meningiomas. Six months after surgery, use of antiepileptic medication was less in grade 0-I compared with other grades.
  
  
  CONCLUSIONS
  When histologic grade is fixed, the Simpson grading system is the prime predictor for recurrence of meningioma after resection. Grade 0-I resection is also beneficial in cutting off antiepileptic medication in patients with convexity meningiomas. Although complete tumor resection (grade 0-I) is the goal, the surgical approach should be tailored to each patient depending on the risks and surgical morbidity.
authors.affiliation: Department of Neurosurgery, LSU Health-Shreveport, Shreveport, Louisiana, USA. Electronic address: ananda@lsuhsc.edu.
authors.forename: Anil
authors.initials: A
authors.lastname: Nanda
authors.affiliation: Department of Neurosurgery, LSU Health-Shreveport, Shreveport, Louisiana, USA.
authors.forename: Shyamal C
authors.initials: SC
authors.lastname: Bir
authors.affiliation: Department of Neurosurgery, LSU Health-Shreveport, Shreveport, Louisiana, USA.
authors.forename: Subhas
authors.initials: S
authors.lastname: Konar
authors.affiliation: Department of Neurosurgery, LSU Health-Shreveport, Shreveport, Louisiana, USA.
authors.forename: Tanmoy K
authors.initials: TK
authors.lastname: Maiti
authors.affiliation: Department of Neurosurgery, LSU Health-Shreveport, Shreveport, Louisiana, USA.
authors.forename: Papireddy
authors.initials: P
authors.lastname: Bollam
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008577:Meningeal Neoplasms / Q000150:complications* / Q000000981:diagnostic imaging / Q000601:surgery*; D008579:Meningioma / Q000150:complications* / Q000000981:diagnostic imaging / Q000601:surgery*; D008875:Middle Aged; D060787:Neoplasm Grading; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis*; D012372:ROC Curve; D012189:Retrospective Studies; D014944:World Health Organization; D055815:Young Adult
keywords: Antiepileptic; Medication; Meningiomas; Neuronavigation; Recurrence; Simpson grade; survival