Dr Tomasz Skaba.Certified NeurosurgeonSilesian University of Medicine
AVM is a congenital mal development of blood vessels with one or more direct communication between arterial and venous channels
Most common in cerebral hemispheres, frequently in MCA territory
Involves one or combination of Epi cerebal Trans cerebral Sub ependymal circulation
Incidence – 0.14% Presents usually at 40 years, no sex prelidiction Low peripheral resistance in avm high flow
volume progressive arterial enlargement
Haemorrhage: More common in small AVM due to high
pressure in feeding arteries Annual risk of haemorrhage – 2-4% Rebleed in 1st year – 6% Cumulative risk in 25 years – 53% Death from initial AVM rupture – 10% Neurological deficit – 50% with each
haemorrhage
Risk of bleeding [ atleast once]
expected years of remaining life
=1-(annual risk of not bleeding)
Seizures – common in large AVM bcos it involves cortex
Headache – 5-35% Raised ICP due to increased venous sinus
pressure Hydrocephalus due to SAH Intellectual deterioration
CT – For screening, serpentine veins seen , haemorrhage , calcification
MRI – relationship of AVM to surrounding brain, hypo in T1, flow voids, for MR assisted stereotactic navigation, Fmri + neuronavigation
CT angio better than conventional angio Look for – feeding arteries , passing arteries,
draining veins, steal, associated aneurysm in parent vessel/ intranidal
Grade = total points 1-5Grade 6 –inoperable or not amenable to any treatment modalityGood/ excellent surgical outcome with respect to SM grading [heros et al]
SM grade % 0f cases with good results with surgery
1 100
2 94
3 89
4 61
5 29
Resectability depends on SM grading, flow thru AVM [high/low], vascular steal
Surgical risk vs risk of bleeding Needs meticulous disection
Treatment options pros cons
Surgery Is the treatment of choice
1 Eliminates the risk of bleeding immediately2 Seizure control improves
1 Invasive2 Risks of surgery
SRS –For nidus less than 3cm, deep seated AVM
1 Out patient procedure2 Non invasive3 Gradual reduction of
AVM flow 4 No recovery period
1 Takes 1-2 years to work with risk of bleeding during that period2Not useful for large lesion
embolisation 1 Facilitates surgery/SRS
1 Inadequate by itself to obliterate AVM
2 Induces haemodynamic changes
3 May require multiple sitting
4 No effect on progression of neurological symptoms, seizure frequency
Obliteration rate is 80 – 85 % for small AVM RADIATION NECROSIS – 1% Haemorrhage after radiation- 10%
Onyx – used now Timing : 3-30 days before surgery, 30 days
before SRS RISK – death 1%, bleed – 3%, rebleed 7%, mild
deficit- 9%, NPPB
Grade 1& 2 surgery Grade 3-5 individualised planning, combination of 3 treatment
modalities