Evaluation of prognostic factors as predictor of AVMS obliteration after Gamma Knife radiosurgery

Acta Neurochir (Wien). 2013 Apr;155(4):619-26. doi: 10.1007/s00701-013-1631-2. Epub 2013 Feb 19.


Background: The reported AVMs obliteration rate after Gamma Knife radiosurgery (GKS) ranges from 70 to 94 %. The objective of the present study was to assess prognostic factors predictive for cerebral AVMs obliteration in 127 patients who underwent GKS.

Methods: The AVMs were classified according to the Spetzler-Martin classification. Twenty-one cases (16.5 %) were classified as grade I, 46 cases (36.2 %) as grade II, 51 cases (40.1 %) as grade III, and nine cases (7.1 %) as grade IV-V. The AVMs were deeply located in 16.5 % of patients. The peripheral prescription dose ranged from 16 to 30 Gy (mean 22.3 Gy). The AVMs volume ranged from 0.1 to 13 cc (mean 2.7 cc).

Results: In 72 patients out of the 104 (69.2 %) with a radiological follow-up, MRI showed the AVM obliteration; in 54 cases (60 %) out of the 90 that performed a DSA, a complete AVM obliteration was achieved (average closure time 48.5 months). The volume of the nidus (p = 0.001), the prescription dose (p = 0.004), the 2002 Pollock-Flickinger classification (p = 0.031), and their 2008 revised classification (p = 0.025) were found to be statistically significant in predicting the probability of AVM closure. In the multivariate analysis, only the prescription dose was found to be an independent prognostic factor (p = 0.009) for AVM obliteration.

Conclusions: The volume of the nidus and the prescription dose significantly influence the outcome of radiosurgical treatment. The Pollock-Flickinger classification was found to be a reliable scoring system in predicting the AVM closure and an important tool for selection of patients candidate for GKS.

MeSH terms

  • Adult
  • Cerebral Angiography / methods
  • Female
  • Humans
  • Intracranial Arteriovenous Malformations / classification
  • Intracranial Arteriovenous Malformations / diagnosis*
  • Intracranial Arteriovenous Malformations / diagnostic imaging
  • Intracranial Arteriovenous Malformations / surgery
  • Magnetic Resonance Imaging / methods
  • Male
  • Middle Aged
  • Predictive Value of Tests*
  • Prognosis
  • Radiosurgery / methods*