Spinal avm

1. SPINAL AVM – CLASSIFICATION
AND MANAGEMENT
06-Jan-16
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2. Spinal Cord Vascular Malformations
It represent a heterogeneous group of non-neoplastic vascular
abnormalities
Spinal arteriovenous malformation (AVM) is an abnormal
tangle of arteries and veins in which the arteries feed directly
into the veins with abnormal intervening capillary bed.
AV fistula (AVF): direct communication between artery & vein
AV malformations (AVMs): multiple complex communications
Nidus: the core of an AVM that appears angiographically and
anatomically as a conglomeration of vessels because of the
superimposition of arteries and veins.
06-Jan-16
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3. Incidence
 Rare cause of neurologic dysfunction
 5% of all intraspinal pathology
 Occur throughout the spine
 Affect any age group, majority: 30-50
 Better diagnosis and management with improved
techniques of spinal angiography, MRI, MRA
and endovascular surgery
O`Toole and McCormick. Chapter 83: Vascular Malformations of the Spinal Cord.
Rothman-Simeone The Spine. 5th Edition
06-Jan-16
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4. HISTORY AND CLASSIFICATION
 Classification of spinal AVM has evolved with the
technology available to study them.
 Earliest studies were based on postmortem examinations.
 1888, Gaupp described them as “hemorrhoids of the pia
mater spinalis”.`
 In 1914, Charles Elsberg performed the first successful
operation on a spinal cord AVM.
 1925 – Sargent: classified 19/21 cases as venous angiomas
 1943 – Wyburn Mason classified AVMs into histological
groups arteriovenous angiomas and purely venous
angiomas(more common)
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5.  Baker –layton in 1967 classified AVM s into 3
categories:
Type 1 - single coiled vessel type
Type 2 - Glomus AVM
Type 3 - juvenile AVMs
• 1977 – Kendall and logue identified AVFs in the
dural sleeve of spinal nerve roots which were
consistent with single coiled vessel type of
AVMs.
HISTORY AND CLASSIFICATION
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6. HISTORY AND CLASSIFICATION
 Two additional advances in the last 25years
1977 – Recognition by Djindjian that some
intradural lesions that were previously
considered AVMs of the spinal cord are actually
simple AVFs in the pia(Perimedullary AVFs)
Recognition of cavernous angiomas
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7. Classification: Berenstein A(1999)
 Spinal cord vascular malformation
Isolated - AVMs and Av fistulas
Multiple – Metameric (Cobb syndrome and other
associations) and non metameric (Rendu –Osler
– weber syndrome)
• Spinal cord telangiectasias
• Cavernomas
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8. Classification: Anson, Spetzler(1992)
 Most widely accepted. 4 types
Type 1: AV Fistula located between a dural
branch of the spinal ramus of a radicular artery
and an intradural medullary vein
Type 2 : Intramedullary glomus malformation
with a compact nidus within the substance of the
spinal cord
Type 3: Juvenile or combined AVMs -extensive
AVM often extending to the vertebra or
paraspinal tissues.
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9. Type 4 : Intradural perimedullary arteriovenous
fistula
 A – simple fistula fed by a single arterial
branch.
B – Intermediate sized fistula with multiple
dilated arterial feeders
C – Large perimedullary fistula with multiple
giant arterial feeders.
Classification: Anson, Spetzler(1992)
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10. MODIFIED CLASSIFICATION OF
SPINAL CORD VASCULAR LESIONS
1. NEOPLASTIC VASCULAR LESION
• Hemangioblastoma
• Cavernous malformation
2. SPINAL ANEURYSM
3. AVF :
Extradural
Intradural
• Ventral (Small/Medium/Large shunt)
• Dorsal (Single/Multiple feeder)
4 AVM
• EXTRADURAL-INTRADURAL
• INTRADURAL
• CONUS MEDULLARIS
Spetzler and Detwiler 06-Jan-1610

11. Arterial Anatomy
1. Anterior spinal artery:
 Arises from the fusion of a contribution from each of the vertebral
arteries
 Supplies the ventral 2/3 of the cord
 Important contribution to the ASA is from the artery of Adamkiewicz,
which may arise anywhere from T8 to L1, more often on the left side.
 The anterior spinal axis in the anterior commissure of the spinal cord
and gives rise to perforators throughout its length.
2. Paired posterior spinal arteries:
 run the length of the spine
 supply the posterior 1/3 of the cord
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12. Arterial Anatomy
3. At each segmental level: a dorsal ramus of the
segmental artery enters the intervertebral foramen and
gives rise to 3 branches:
 Dural branch: to dura
 Radicular branch: to nerve root
 Medullary branch:
 Augments the flow to the anterior spinal artery
 During the 3rd stage of fetal development, most of the medullary
branches involute  distal portion of the cord relatively ischemic
 Somewhere between T8 & L2, especially on the left: the
medullary branch does not involute and becomes the artery of
Adamkiewicz
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13. Arterial Anatomy
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14. Venous Anatomy
 Coronal venous plexus:
 A plexus on the cord surface
 Formed by coalescence and anastomosis of radial veins
 Epidural venous plexus:
 At segmental levels, medullary veins leave the coronal plexus
and exit the intervertebral foramen to join the epidural plexus
 The plexus communicates with the venous sinuses of the
cranial dura
 It drains into the ascending lumbar veins and the azygous
venous system
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15. Pathophysiology of Symptoms
 Depends on the type of the AVM
High-flow:
Ischemia
Hemorrhage
Slow-flow:
Venous congestion
Mechanical compression of the spinal cord and
roots
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16. CLINICAL PRESENTATION
The clinical signs are due to:
(1) SAH;
(2) haematomyelia;
(3) steal into AVF/AVM;
(4) venous hypertension;
(5) thrombosis of draining vein,
(6) pressure of aneurysm, venous or arterial, true or false;
(7) arachnoiditis;
(8) syringomyelia and
(9) Foix-Alajouanine syndrome, a result of chronic venous
ischaemia of the spinal cord.
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17. Dural Arterio-
Venous Fistula
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18. Type I (Dural AV Fistula)
 The most common type
 60% of spinal AVF/AVM
 Single AV connection within the
dura of the nerve root sheath
 Results in dilated arterialized
coronal venous plexus
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Dural AV Fistula
Medullary
vein

19. Spinal Dural Arteriovenous Fistula
 Represent at least 35% of all spinal vascular
malformations in large series, although some estimates
range as high as 80%
 Most commonly occur at thoracolumbar levels, usually
between T5 and L3
 It represents an AV shunt that occurs within dural
covering of spinal cord, below and medial to the pedicle.
 Located adjacent to intervertebral foramen or within
dural root sleeve, with arterial supply arising from dural
branch of radicular artery.
 An intradural vein drains the shunt directly into the pial
veins of the cord J Neurosurg 1983;59:1019-1030.06-Jan-16
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20. Pathophysiology
 AV shunting result in venous engorgement and
venous hypertension involving the spinal cord
(Venous congestion, steal phenomenon, ischemia
and hemorrhage)
 Most often, no direct arterial supply to the spinal
cord itself originates from the radicular artery
feeding an SDAVF.
 In 10% to 15% of cases, however, SDAVF is fed
by a radicular artery that also supplies spinal cord
via a radiculomedullary or radiculopial branch
Radiology 1985;154:687-689.
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21. SUBACUTE NECROTIZING MYELOPATHY
VENOUS HYPERTENSIVE MYELOPATHY &
Cord edema, stagnation of bloood flow , blood – CNS disruption
Intramedullary vasodialation, Loss of autoregulatory capacity
Tissue perfusion ( hypoxia )
Intramedullary arteriovenous pressure gradient
Venous engorgement & venous hypertension
Increased pressure & engorgement of pial veins
Intradural vein  Pial veins
PATHOPHYSIOLOGY
06-Jan-1621

22. Clinical presentation
 Most common spinal vascular anomaly in older adult, afflicts males
in 80% to 90% of cases
 Presents after the fourth or fifth decade;
 Chronic progressive myelopathy leads to progressive lower extremity
weakness, often characterized by both UMN & LMN signs.
 Localized or radicular back pain, bowel, bladder, and sexual
dysfunction -Often exacerbation by excersise
 Claudication pain is a common presentation in dural AVF.
Claudication pain and neurological deficit may be worsened by a
heavy meal
 Lead to paraplegia within 2 – 4 years.
 Never bleeds.
 15% of the patients have rapid neurological worsening and is called
 Foix alajouanine syndrome and is due to venous congestion and
should be treated immediately 06-Jan-16
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23. Imaging
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Anteroposterior (A) and lateral (B) lumbothoracic spine radiographs reveal
medial erosion of the pedicles (A, arrows) and scalloping of the posterior
aspect of several vertebrae (B).

24. MRI
 Conus and lumbar enlargement of the cord are almost
uniformly affected; however, abnormal signal may
extend into upper thoracic cord levels – Non specific.
 Hallmark of diagnosis is demonstration of dilated pial
veins of cord, most commonly along dorsal surface.
 MR reflect pathophysiologic features of SDAVF
including cord edema and venous hypertension with
engorgement of the pial veins
 Ischemia and venous infarct can occur.
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25. 06-Jan-1625

26. 06-Jan-16
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27. SPINAL ANGIOGRAPHY :
•AVF shunt below or medial to the pedicle .
•The draining vein is almost 10 times larger than feeding
artery.
•The arterial flow is slow .
•Recently, the use of time-resolved imaging of contrast
kinetics (TRICKS) has improved the detection rate and
accuracy of MRA and DSA for diagnosis and localisation
is often unnecessary.
06-Jan-1627

28. Type II (Glomus AVMs)
 Analogous to intracranial AVMs
 Tightly packed nidus of dysmorphic
arteries and veins in direct
communication w/o capillary bed; over a
short segment of the spinal cord
 The nidus may be completely or partially
intramedullary
 Typically lie in the anterior half of the
spinal cord and are supplied by one or
two medullary arteries via the anterior
spinal artery
 Usually at the cervicothoracic junction
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29. glomus type
•Compact nidus
•Intramedullary
• Multiple branches of ASA
& PSA
•High pressure
•Relatively low resistance
•High blood flow
•Aneurysm common
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30. Pathophysiology of Type II
 Vascular steal mechanism: High-flow lesion; AVM
nidus acts as a low-resistance sump siphoning blood
away from the surrounding normal spinal cord
 Dysmorphic vessels susceptible to hemorrhage
 Mass effect: myelopathy or radiculopathy
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31. Clinical Presentation of Type II
 Childhood or adult years
 Acute presentation from subarachnoid or intramedullary
hemorrhage is most common
 Acute onset of severe neck or back pain “coup de
poignard” approximates the level of AVM: typically the
first symptom of AVM hemorrhage
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32. Juvenile
Spinal
AVM
Intramedullary
&
extramedullary
+/-
extraspinal
extension
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33. Vascular anatomy – Intradural AVMs
Juvenile type (TYPE 3):
 These lesions are fed by multiple
enlarged medullary arteries via the
anterior and posterolateral spinal
arteries and may have a
voluminous nidus that completely
fills up the thecal sac.
 The nidus also has intervening
neural tissue.
 These may frequently involve
vertebrae and paraspinal tissues .
 These lesions are high-flow AVMs;
a spinal bruit may indicate their
presence.
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34. JUVENILE SCAVM
EXTRADURAL-INTRADURAL AVM
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35. SYMPTOMS
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• MALE or FEMALE
• Age : 2 or 3 decade
Nearly 50 % < 16 years .
• 30 %  weakness as initial symptoms
• 20 %  Back pain at onset .
• Over 70 %  develop sensory symptoms
• 50 %  Spinal hemorrhage
• Bladder & bowel involvement

36. •Slow flow AVM  Myelopathic symptoms .
• High flow AVM  Bleed:
•HEMORRHAGE :
•SAH OR intramedullary bleed ,
•High mortality ( 30 % )
•High rate of bleeding (40 % within first year )
ACUTE MEDULLARY SYNDROME .
May progress rapidly , or there may be partial
remissions.
Prognosis : Poor .
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37. Imaging
 Flow voids representing enlarged arterial feeding vessels
and intramedullary nidus are well seen
 Haemorrhage is also seen in various stages.
 Nonhemorrhagic intramedullary signal abnormality
adjacent to the nidus and most likely indicates gliosis,
edema, or areas of cord infarction.
 Extension of nidus into extramedullary structures,
paraspinal soft tissue structures, is also well seen on MR
 Angiographic evaluation of delineation of all feeding
vessels, aneurysms, locating the nidus within the cord,
and mapping the size and location of draining veins.
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38. IMAGING : AVMs
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 MRI : best noninvasive modility
 Flow voids  enlarged arterial feeding vessels
 Intramedullary nidus
 Recent / remote intramedullary hemorraghe
 T2W Hyperintensity : gliosis, edema, infarction
 Draining veins :
• Flow voids,
• Ectasia ,
• Mass effect,
• Thrombosis
 Intramedullary contrast enhancement

39. 06-Jan-16
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Juvenile-type
intramedullary (AVM) of
the cervical and thoracic
segments
Right vertebral
arteriography,
anteroposterior (A) and
lateral (B) views,
demonstrates the
superior aspect of a large
intramedullary AVM that
extends from C4 to T2.
The nidus of the AVM fills
the spinal canal from
front to back and from
side to side.

40. 06-Jan-16
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On sagittal T1-weighted
magnetic resonance imaging ,
the signal void from the AVM
clearly involves not only the
cross-sectional area of the spinal
cord but also the anterior and
posterior elements of the spine
and paraspinous soft tissue

41. glomus type
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Selective spinal cord arteriogram demonstrating a
glomus-type intramedullary arteriovenous
malformation supplied by the anterior spinal
artery via the artery of Adamkiewicz

42. Feature SDAVF SCAVM
Age >4th decade 2nd-3rd decade
Symptom onset Slow progressive Acute
Male predominance Yes (marked) Minimal
Hemorrhage No Yes (frequent)
Bruit No 5-10%
Origin Acquired Congenital
Site of nidus Dura, root sleeve Spinal cord
Medullary arterial
supply involved
10-15% 100%
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43. Perimedullary
Fistula
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44. Perimedullary arteriovenous fistulas
 Consist of direct AVF located on
the cord and fed directly by arteries
supplying the cord, most frequently
the ASA
 8-19 % of spinal AVM.
 Single hole between one or more
radiculomedullary arteries &
perimedullary veins on the surface
of cord .
 Features that differentiate SCAVFs
from both SDAVFs and SCAVMs
 Intradural location of shunt,
 constant involvement of arteries supplying
the spinal cord, and
 lack of intervening nidus
44
06-Jan-16
AV fistula

45. Etiology And Clinical Presentation
 Believed to be congenital lesions, usually present in patients in
their second through fourth decade
 Most common neurologic presentation is one of progressive
asymmetrical radiculomedullary signs involving lower
extremities, reflecting the most common location of SCAVFs in
the lower thoracic or lumbar region
 Hemorrhage is also common and has been noted in nearly one
third of patients at presentation
 Three subtypes have been identified based on the size and
number of vessels involved
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46. Perimedullary AVF
 A – Simple perimedullary fistula fed by single arterial
branch. (Venous drainage minimally dilated)
 B – Intermediate sized fistula with multiple dilated
arterial feeders. (ASA & PSA are mildly dilated and
draining vein markedly dilated)
 C – Large perimedullary fistula with multiple giant
arterial feeders.(Main supply is ASA and draining
proximal venous segment is ectatic)
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47. SYMPTOMS
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Young adults , 2 – 4 Decade
No sex predilection .
Most common presentation :
• Progressive asymmetrical radiculomedullary signs,
involving lower extremities .
• Progressive paraplegia without remission.
• Impaired venous return & long intradural course of
the venous drainage may be responsible for
ascending myelopathy & spinal cord ischaemia .
• Spinal SAH  In 1/3 patients .

48. IMAGING
 Flow voids - enlarged feeding and draining vessels of
SCAVF.
 Intrinsic cord signal abnormality and evidence of
hemorrhage may also be present.
 Small size of some lesions and lack of nidus may make
differentiation from SDAVF difficult.
 Abnormal enhancement of the cord may be present.
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49. PERIMEDULLARY
AVF
3D PC MRAT1WI
06-Jan-1649

50. MRI
SCAVM PMF SDAVF
Flow voids + + +
Parenchymal
signal changes
+ + +
Aneurysm + + -
Hemorrhage + + -
Nidus in the cord - -
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51. Radiological differences between dural
AVM and Intradural Avm
Dural AVM Intradural AVM
Site of nidus Lateral canal
100%
Within cord 80%
Level of spine Lower half diffuse
Rapid flow 0 80%
Assoc aneurysm 0 44%
Supply by
medullary artery
15% 100%
Route of drainage Rostral 100%
Caudal 4%
Rostral 81%
Caudal 72%
06-Jan-1651

52. Cavernous Malformation
 Cavernous malformations
(CMs) are slow flow vascular
malformations without AV
shunting
 3% to 5% of CMs involve the
spine
 Site- Most often intramedullary
and occur proportionally
throughout the cord
 CMs of the spine have been
noted to preferentially affect
females
 It can arise denovo, post
radiotherapy and post traumatic.
06-Jan-16
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53. Clinical presentation
 Symptoms may begin at any age, patients most often
present in the fourth decade
 Acute presentation is probably secondary to hemorrhage
either within vascular spaces of malformation or into
surrounding parenchyma (hematomyelia)
 Progressive myelopathy may result from growth or
enlargement of the lesions by several mechanisms
including vessel dilation, repeated hemorrhage, or
capillary proliferation
06-Jan-16
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54. IMAGING
 Varies in size from mm to cms.
 Well demarcated with low grade hemorrhage of
varying ages
 Surrounded by hemosiderin stained gliotic neural
tissue.
 Histology show single cell layer to hyalinized,
thickened walls containing densely packed
collagen but no elastic or smooth muscle fibres.
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55. Cavernous Malformation- treatment
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 They are not subjects for endovascular treatment, and
surgical resection is advocated for symptomatic lesions.
 It is generally reserved for symptomatic lesions

56. AVM/AVF-Treatment
Treatment planning for spinal vascular
arteriovenous lesions is based on
The hemodynamics of the lesion,
Location in the axial and longitudinal plane, and
The angioarchitecture.
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57. EMBOLIC AGENTS
Particulate materials
 Poly vinyl alcohol(150-250micro) :Temporary & Reduces arterial steal
safely.
 Gelfoam
 Sponge microparticulate
Balloon occlusion
Liquid agents
 N-butyl cyanoacrylate (NBCA) : If AVM is supplied by only PSA
 ethylene vinyl alcohol copolymer)
 If AVM is supplied by ASA , embolization only if :
 Normal anterior RMA supplying above & below the
AVM.
 Superselective catheterization , close to nidus.
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58. Treatment - Dural AVF
 Goal of treatment of spinal dural AVF is permanent
elimination of of venous congestion of the spinal
cord
 Simple interruption of the AvF produces permanent
resolution of venous congestion and improvement
of myelopathy.
 Medullary vein(arterialised) is coagulated
 Neurological outcome is closely related to preop
function.
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59.  Endovascular occlusion of SDAVF is possible in
more than 80% of cases and can be accomplished
at the same time as the diagnostic angiogram using
permanent liquid embolic agents such as
NBCA(N-butyl cyanoacrylate) or ONYX.
 Perimedullary venous thrombosis.
 Clinical symptoms may worsen.
 Post procedure anticoagulation for 3 months.
Treatment - Dural AVF
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60. TREATMENT : AVMs
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 Should be pursued aggressively because of the poor
outcomes in untreated patients.
AIM : To suppress the risk of hemorrhage & arrest
progression of neurological defecit .
 Maximum suppression of arterial steal may reverse a
progressive neurological defecit.

61. EMBOLIZATION
• Method of choice .
• Risk of embolization is 3 to 5 times lower
than surgery .
• Angiographic criteria for endovascular
approach is
 Enlarged prominent ASA
 Multiple commissural branches
participating in AVM .
 Normal ASA above or below the AVM .
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62. TREATMENT : Perimedullary AVF
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Type I: Embolisation is not indicated if the fistula is surgically accessible since
surgery is the safer and more reliable treatment.
• Catheterisation in the anterior spinal artery can be difficult and is always
hazardous.
• Fistulas situated on the ventral cord surface are candidates for embolisation
which has been performed with particles (as a presurgical manoeuvre) or
NBCA
Type II: If the fistula is situated on the dorsal surface of the cord, surgical ligation
and embolisation are of equal value and efficacy.
• Ventral lesions are difficult cult to approach surgically but difficult cult to
completely exclude by embolisation, if there are multiple feeders
Type III: The high-flow and dilated vessels in this type makes surgery difficult, and
embolisation with coils or liquids is usually performed as curative or presurgery
procedures.

63. TREATMENT : Perimedullary AVF
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63
 SURGERY :
1. Smaller lesion ,
2. AVF I & II , located posterior to the spinal cord
3. Endovascular treatment failed in AVF III .

64. Intradural arteriovenous fistula at surgery (A) Before, (B) After
obliteration
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64

65. Summary of outcomes of treatments for spinal
vascular malformations
06-Jan-16
Intramedullary AVM Surgery Curative resection
if possible
Embolisation (curative or
palliative)
Particles: high recurrence
NBCA: better cure rates
Onyx: no data
Perimedullary AVF Type I. Surgery (or embolisation)
Surgery first-line
treatment if AVF accessible
NBCA embolisation, but
particles may be safer
Perimedullary AVF Type II EVT (or surgery) NBCA, particles or surgery
Perimedullary AVF Type
III
EVT (surgery if
incomplete)
Coils, (balloons), NBCA or
Onyx
DAVF EVT (surgery if recurrent) NBCA or Onyx
65

66. Indications for occluding only the feeding vessels
Dural AVM
Intramedullary diffuse AVM
Combined AVM
Conus medullaris AVM
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67. Complications
Complications that result from open surgical ligation or
resection
 Infection of meninges (meningitis)
 Cerebrospinal fluid leak
 Wound dehiscence
Complications that result from the endovascular technique
 Femoral hematoma
 Pseudoaneurysms and thrombosis
 Arterial dissection
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68. Stereotactic radiosurgery
Single high dose SRS
20 to 30% rate of occlusion.
Hypofractionated irradiation
Internal fiducial markers and image‐guided
radiation allow stereotactic irradiation for spinal
disease with real‐time verification and an
accuracy of ±1 mm for every 0.03 seconds
06-Jan-16
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69. Type Typical
location
Vascular
supply
Presentation &
course
Clinical
associations
Treatment
DAVF Lumbar,
thoracic
Dural
arteries
Chronic
myelopathy
None 1.Embolizati
or
2.Surgery
AVM Cervical,
thoracic,
Lumbar
Spinal
arteries
(ASA,
PSA)
Acute;
hemorrhage
common
Vascular
syndromes;
paraspinal
involvement
rarely
1.Embolizati
or
2.Surgery
PAVF Lumbar,
thoracic
Spinal
arteries
(ASA >
PSA)
Acute or
chronic; may
hemorrhage
None 1.Embolizati
or
2.Surgery
CM Cervical,
thoracic,
Lumbar
Minimal Acute or
chronic; may
hemorrhage
Intracranial or
familial CM
Surgery
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70. Grade Gait
0 Normal
1 Leg weakness, abnormal gait or stance, but no restriction of activity
2 Restricted activity
3 Requiring 1 stick for walking
4 Requiring 2 sticks, crutches, or walker
5 Confined to wheelchair
Grade Micturi tion
0 Normal
1 Hesitancy, frequency, urgency
2 Occasional urinary incontinence or retention
3 Total incontinence or persistent retention
Modified Aminoff-Logue grading scale
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71. THANK YOU
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