draining vein shielding in avm- a new technique in gamma knife

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 SHOULD BE DONE?

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.

CASE STUDY-1

CASE STUDY 1

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CASE STUDY 4

draining vein shielding in avm- a new technique in gamma knife

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