CEREBRAL ARTERIOVENOUS MALFORMATION

(AVM)

Randy Reichenfeld

WHAT IS AN AVM?

An AVM is an abnormal connection between the arteries and veins.

Consist of feeding arteries, nidus, and draining veins.

AVM

They can occur anywhere but mostly in the brain and the spine.

Can by asymptomatic and never detected. Symptomatic AVMs may need treatment. Hinders gas exchange On occasion a patient with AVM can become

aware of ‘whooshing’ sounds and may cause loss of sleep and psychological distress.

Can rupture/hemorrhage causing brain damage or death (2-4% per year)

AVM- CAUSE

Unknown Congenital

Symptoms at any age May or may not be hereditary Occur in males and females of all racial or

ethnic backgrounds at roughly equal rates. 300,000 Americans

12% symptomatic 1% die of direct result

10% mortality associated with the first hemorrhage, and up to 30% mortality associated with each rebleed

SYMPTOMS

Depends on location in brain Headache Epilepsy Confusion Tinnitus Dizziness Blurred vision numbness (any part of body)

DIAGNOSING

CT/CTA Hemorrhage in the 4th

ventricle Difficult on non

contrast CT. Enlarged draining veins

may be seen. With contrast is much

easier but exact anatomy may still be unclear so DSA is still necessary

DSA (DIGITAL SUBTRACTION ANGIOGRAPHY)

-Gold standard-Able to identify the exact number of feeding vessels and pattern of drainage.

DIAGNOSING- MRI

-Right thalamic AVM

-Flow voids (black) evident on T2

-Hemorrhage and edema may also be detected using MRI

MRA

-Useful to subtract the hematoma components when a hemorrhaged AVM needs to be imaged

SPETZLER-MARTIN AVM GRADING SYSTEM

Used to evaluate the surgical risks AVM given a rating of 1-5 Based on

Size small (<3cm) = 1 medium (3 - 6cm) = 2 large (> 6cm) = 3

Eloquence (degree of functional importance) non-eloquent = 0 eloquent = 1

Venous drainage superficial only = 0 deep = 1

TREATMENT

Can either be Surgical Non surgical

Stereotactic Radiosurgery Endovascular Therapy

TREATMENT- SURGERY

Spetlzer Martin Grades 1-3 Complete resection of AVM in one operation Advantages

immediate elimination of hemorrhage and rehemorrhage risk, and improvement in seizure control

Risks Spetzler-Martin Grades 1-3 AVMs carries a 1-10%

chance (respectively) of significant neurological complication

TREATMENT- SURGERY

1)T2 MRI shows small AVM in frontal lobe2)Craniotomy3) Dura exposed4)Dura removed, showing arachnoid

1)neuronavigation image in real-time2) Surface feature of AVM3) Resection begins4) Resected AVM

TREATMENT- STEREOTACTIC RADIOSURGERY

Uses GammaKnife or Linear Accelerator (Linac), to deliver a focused beam of radiation to the nidus of the AVM.

Used for Deep AVMs or Spetlzer Martin grade 3+ Advantages

Painless, well tolerated by most patients Risks

secondary tumors impairment of brain function cystic radiation necrosis

average 2-3 years for the AVM to be cured significantly higher rate of rebleeding among AVMs

treated with SRS compared with AVMs treated surgically.

TREATMENT-ENDOVASCULAR

involves placement of metallic microcoil or glue like substance in the lumen of arteries feeding the AVM in order to slow the flow of blood, encouraging AVM feeder arteries to clot off.

rarely cures an AVM Helpful supportive measure for

future open surgery or stereotactic radiosurgery.

risk of death or significant neurological disability is about 4-5%

CASE STUDY

Andrea is a 41-year-old female with a medical history of Klippel-Trenaunay Syndrome (an abnormality associated with enlarged blood vessels in an extremity) and for Andrea her left leg is affected. She woke numbness and heaviness in her leg and went to the Emergency Department.

CASE STUDY

T2 weighted MRI shows an AVM in the left temporal lobe.

CASE STUDY

DSA confirms AVM

Andrea’s doctors agree the best form of treatment is surgical removal.

CASE STUDY

Post operative DSA confirms the complete removal of the AVM