title: Impact of 5-aminolevulinic acid fluorescence-guided surgery on the extent of resection of meningiomas--with special regard to high-grade tumors.
abstract: OBJECTIVE
  In high-grade meningiomas and a subgroup of clinically aggressive benign meningiomas tumor control is still insufficient. Recently 5-ALA fluorescence in meningiomas was reported. The impact of 5-ALA fluorescence-guided surgery (FGS) on surgical decision-making and extent of resection has not yet been systematically analyzed, especially not in high-grade meningiomas. The present study deals with three main questions regarding 5-ALA FGS in meningiomas: to assess the potential for discriminating different WHO grades intra-operatively, to analyze the influence on surgical strategy and to evaluate the impact on extent of resection.
  
  
  METHODS
  Data from 31 meningiomas operated with 5-ALA FGS were retrospectively analyzed. Intraoperative fluorescence was graded by the surgeon as "no", "low" or "high". Correlations between semi-quantitative fluorescence and histological features (WHO grade) were analyzed. The influence of 5-ALA fluorescence on surgical strategy and the impact of 5-ALA FGS on degree of resection (Simpson grade and post-operative imaging) were studied. In tumors showing infiltrative growth the extent of resection of fluorescence positive tissue was evaluated.
  
  
  RESULTS
  The population comprised 19 WHO grade I, 8 grade II and 4 grade III tumors (61% benign and 39% high-grade meningiomas). 94% of the tumors showed positive fluorescence. Different fluorescence intensities were observed: "no" in two, "high" in 12 and "low" in 17 tumors, respectively. A significant correlation between fluorescence intensity and WHO grade was found (ρ=0.557, p=0.001). 5-ALA improved the extent of resection in 3/16 (19%) of grade I and in 6/8 (75%) of grade II/III meningiomas. This improvement was not measurable by the Simpson grading as rated by the surgeon and controlled on post-operative imaging.
  
  
  CONCLUSIONS
  In the present population a strong correlation between fluorescence intensity and WHO grade was observed. 5-ALA FGS improved the extent of resection in meningiomas. Especially in high-grade tumors additional information on brain and neurovascular infiltration was provided. The improved resection was not measurable by Simpson's grading necessitating an additional item, which rates residual fluorescence. Long-term studies are necessary to evaluate a possible impact of FGS on recurrence and overall survival.
authors.affiliation: Department of Neurosurgery, University Hospital, Heinrich Heine Universität, Düsseldorf, Germany. Electronic address: jfcornelius@yahoo.com.
authors.forename: J F
authors.initials: JF
authors.lastname: Cornelius
authors.affiliation: Department of Neurosurgery, University Hospital, Heinrich Heine Universität, Düsseldorf, Germany.
authors.forename: P J
authors.initials: PJ
authors.lastname: Slotty
authors.affiliation: Department of Neurosurgery, University Hospital, Heinrich Heine Universität, Düsseldorf, Germany.
authors.forename: M A
authors.initials: MA
authors.lastname: Kamp
authors.affiliation: Department of Neuropathology, University Hospital, Heinrich Heine Universität, Düsseldorf, Germany.
authors.forename: T M
authors.initials: TM
authors.lastname: Schneiderhan
authors.affiliation: Department of Neurosurgery, University Hospital, Heinrich Heine Universität, Düsseldorf, Germany.
authors.forename: H J
authors.initials: HJ
authors.lastname: Steiger
authors.affiliation: Department of Neurosurgery, University Hospital, Heinrich Heine Universität, Düsseldorf, Germany; Department of Neurosurgery, University Hospital, Rheinische Friedrich-Wilhelms-Universität, Bonn, Germany.
authors.forename: M
authors.initials: M
authors.lastname: El-Khatib
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000622:Aminolevulinic Acid; D003287:Contrast Media; D005260:Female; D005456:Fluorescent Dyes; D006801:Humans; D008297:Male; D008577:Meningeal Neoplasms / Q000473:pathology* / Q000601:surgery*; D008579:Meningioma / Q000473:pathology* / Q000601:surgery*; D008856:Microscopy, Fluorescence / Q000379:methods*; D008875:Middle Aged; D060787:Neoplasm Grading; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D025321:Surgery, Computer-Assisted / Q000379:methods*
chemical_list: D003287:Contrast Media; D005456:Fluorescent Dyes; D000622:Aminolevulinic Acid
keywords: 5-ALA; Aminolevulinic acid; Fluorescence guided surgery; High grade; Meningioma; Skull base