An AVM is an abnormal connection between arteries and veins that allows blood to bypass the capillary bed. AVMs can occur anywhere but are mostly found in the brain and spine. They may be asymptomatic or cause symptoms depending on their location and size. Diagnosis involves imaging tests like CT, MRI, MRA, and DSA. Treatment options include surgery, stereotactic radiosurgery, and endovascular embolization depending on the size, location, and risk profile of the AVM. Complete surgical removal remains the gold standard treatment for lower risk AVMs to eliminate the risk of hemorrhage.

1. CEREBRAL ARTERIOVENOUS
MALFORMATION
(AVM)
Randy Reichenfeld

2. WHAT IS AN AVM?
 An AVM is an abnormal connection between the
arteries and veins.
 Consist of feeding arteries, nidus, and draining
veins.

3. 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)

4. 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

5. SYMPTOMS
 Depends on location in brain
 Headache
 Epilepsy
 Confusion
 Tinnitus
 Dizziness
 Blurred vision
 numbness (any part of body)

6. 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

7. DSA (DIGITAL SUBTRACTION ANGIOGRAPHY)
-Gold standard
-Able to identify the
exact number of
feeding vessels and
pattern of drainage.

8. DIAGNOSING- MRI
-Right thalamic
AVM
-Flow voids (black)
evident on T2
-Hemorrhage and
edema may also
be detected using
MRI

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

10. 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

11. TREATMENT
 Can either be
 Surgical
 Non surgical
 Stereotactic Radiosurgery
 Endovascular Therapy

12. 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

13. TREATMENT- SURGERY
1)T2 MRI shows small AVM in frontal lobe
2)Craniotomy
3) Dura exposed
4)Dura removed, showing arachnoid
1)neuronavigation image in real-time
2) Surface feature of AVM
3) Resection begins
4) Resected AVM

14. 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.

15. 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%

16. 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.

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

18. CASE STUDY
DSA confirms AVM
Andrea’s doctors
agree the best form of
treatment is surgical
removal.

19. CASE STUDY
Post operative DSA
confirms the
complete removal of
the AVM