The study evaluated long-term outcomes of staged-volume stereotactic radiosurgery for large arteriovenous malformations. 61% of patients achieved total obliteration of the malformation. Seizure control and neurological deficits were not significantly improved by treatment. However, the study had a prospective case series design without controls and was subject to selection, information, and attrition biases. Statistical analyses did not include tests to compare outcome curves. The results do not clearly demonstrate benefits of the fractionated radiosurgery approach for large or symptomatic AVMs.

1. Paul P. Huang et al.
“Long-term Outcomes After Staged-Volume
Stereotactic Radiosurgery for Large Arteriovenous
Malformations”
Neurosurgery 71:632–644, September 2012
David Bervini
JC, ASAM
18.10.2012

3. PATIENTS AND METHODS

4. Prospective
Cases series, not randomized
Strong radiosurgery protocol

5. M 35y M 23ml (3)-4-5

6. 23 ml = 23 cm3
• 2.8 cm side cube • 3.5 cm diameter sphere
LARGE?

7. SM (3)-4-5 -> ELOQUENT AREAS
LARGE: “radiosurgical definition”
44% embolization before radiosurgery
When?
Selection bias
Good recovery!

8. • Only 12 underwent FU
DSA
Attrition bias
• FU < 10y
Long-term?

10. Statistical Analysis
KM curves
No information about comparison between
curves (Cox-Mantel log-rank test? Gehan-
Breslow-Wilcoxon test? Peto modification?)
No Cox regression analysis
Statistical bias

11. RESULTS

12. TOT Occlusion rate 61%
29%

15. Information bias

16. 31%, in eloquent regions!

18. P >> .05

19. Number at risk after 5yrs?

20. Seizure Control Neurological deficits
10 Pts before ttt 5 before ttt
6 stable 2 worsening
3 transient increase (not related to heamorrhage)
1 improved
No positive impact of No positive impact of
treatment treatment

21. Take away message
+ -
Strict radiosurgery protocol Poor design
respected for 13yrs
Many bias
Good economy of words
Very poor statistical analysis
Good organization of paper and power
Good relevance and accuracy
of bibliography Distracting graphs
(radiosurgery)
Debatable results
Good quality of illustrations

22. This paper does not help me to understand the
indications and advantages of fractioned
radiosurgery for patients presenting with
“large”, “symptomatic” AVMs.