D E E P A K A G R A WA L , A I I M S , N E W D E L H I
DRAINING VEIN SHIELDING RADIOTHERAPY FOR INTRACRANIAL AVM’S
THE HOLY GRAIL?
INTRODUCTION
• Following gamma knife (GK) therapy for intracranial
AVM’s, obliteration of the nidus occurs over several
years.
• During this period there is a risk of post radiosurgery
imaging (PRI) changes and hemorrhage.
WHAT IS THE ISSUE
• 4.8% per year risk of post-radiosurgery haemorrhage
• 25% may have PRI changes following GK
• Large AVM’s may not be suitable
WHAT IF….
• …we could eliminate/
reduce the post GK
hemorrhage rates ??
• …we could eliminate/
reduce the post GK PRI
changes ??
WHAT I HYPOTHESIZE
• Decreasing radiation dose to the draining vein(s)
may prevent early draining vein obliteration leading
to a decrease in PRI and hemorrhage rates in the
post GK period.
WHAT IS KNOWN
• Early draining vein occlusion has been postulated to
be one of the reasons for hemorrhage & PRI
changes in intracranial AVM’s.
• Factors like vessel wall irregularity, stenosis or
occlusion of the draining vein may lead to
increased intranidal pressure, which in turn
increases the risk of hemorrhage & PRI changes.
• Yen CP, Khaled MA; Schwyzer L, Vorsic M, Dumont AS, Steiner L. Early draining vein occlusion after gamma knife surgery for arteriovenous malformations. Neurosurgery. 2010;67:1293-1302.
• Vinuela F, Nombela L, Roach M, et al. Stenotic and occlusive disease of the venous drainage system of deep brain AVM’s. J Neurosurg. 1985;63:180-184.