1. Treatment of spinal dural arteriovenous malformations: a single center experience
Andres RH, Guzman R, Remonda L†,
Schroth G†, Widmer HR, Seiler RW and Barth A
Departments of Neurosurgery and Neuroradiology†
University Hospital, Berne, Switzerland

2. Spinal dural arteriovenous fistulas (Type I spinal AVM’s)
Most common type of spinal vascular malformations (80%)
Rare and often misdiagnosed entities
Natural history: progressive myelopathy
50% of untreated patients disabled within 3 years
Goal of treatment: definitive occlusion of the fistula
Optimal treatment strategy has yet to be defined

3. Anatomy and pathophysiology
AVM located in the dura of the nerve root and/or adjacent spinal dura
Feeder: radicular artery
Drainage: medullary vein -> retrograde filling of the coronal vein plexus
Congestion and dilatation of the venous plexus
Venous hypertension -> reduced perfusion, ischemia, edema

4. Treatment strategies
Surgical treatment: hemilaminectomy and occlusion of the fistula
Endovascular treatment: catheter embolization
Combined treatment strategy

5. Spinal angiography

6. Surgical anatomy
Fistula point

7. Surgical technique

8. Location of the fistula: thoracic: n=8, lumbar: n=3, sacral: n=1
Study design
12 patients with spinal dural fistulas treated in our institution from 1994 to 2004
9 men, 3 women
Median age: years
Location of the fistula: thoracic: n=8, lumbar: n=3, sacral: n=1

9. Modified Aminoff-Logue grading scale
Grade
Gait
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
Micturation
Hesitancy, frequency, urgency
Occasional urinary incontinence or retention
Total incontinence or persistent retention

10. Results Patient # Age, Sex Localization Treatment ALS pre post Outcome1
67, M
Th 6
Surgical 6 2 +
Endovascular (2x) 5 - 3
57, M
Th 5
Combined 4
68, M
L 1
Endovascular
59, M
76, F
L 2 7
57, F 8
20, M
Th 9 9
74, M
Th 8 10
45, M 11
76, M
Th 7 12
51, F
S 2

11. Results Group n n (OC +) n (OC -) Surgical 3 Endovascular 6 4 2
Endovascular 6 4 2
Combined 1

12. Conclusions
Both endovasular and surgical treatment of spinal dural AVFs resulted in occlusion of the fistula and in a good and lasting clinical outcome in the majority of cases.
For successful surgical occlusion, interruption of the venous drainage on the intradural side of the fistula is mandatory.
In specific situations, a combined neurosurgical and endovascular approach is required to achieve complete occlusion of the AVF.
Embolization should be attempted at the time of diagnostic angiography if the lesion is endovascularly accessible.