Shi and Chen proposed a grading scale for intracranial arteriovenous malformations (AVM) based on 4 anatomic parameters. The grade correlates with operative morbidity. The authors are from Shanghai Medical University in China.
NOTE: The article appeared in the Journal of Neurosurgery immediately after the article by Spetzler and Martin (17.03.01).
Parameters:
(1) size in cm
(2) location and depth
(3) arterial blood supply
(4) venous drainage
Parameter |
Finding |
Grade |
size in cm (diameter) |
< 2.5 cm |
1 |
|
2.5 - 5.0 cm |
2 |
|
5.01 - 7.5 cm |
3 |
|
> 7.5 cm |
4 |
location and depth |
superficial and non-crucial area |
1 |
|
superficial and in functional area |
2 |
|
deep not involving a vital structure |
3 |
|
deep involving a vital structure of the brain (brainstem, diencephalon, etc.) |
4 |
arterial blood supply |
single superficial branch of the middle and/or anterior cerebral artery |
1 |
|
multiple superficial branches of the middle and/or anterior cerebral artery |
2 |
|
(branches of the posterior cerebral artery) or (deep branches of the middle cerebral artery) or (deep branches of the anterior cerebral artery) or (branches of the vertebral artery) |
3 |
|
(verebrobasilar artery) or (main branches from all 3 cerebral arteries) |
4 |
venous drainage |
single, emptying into superficial dural sinuses |
1 |
|
multiple, all drainage into superficial dural sinuses |
2 |
|
(deep cerebral vein emptying into vein of Galen or straight sinus) or (superficial venous drainage) |
3 |
|
deep cerebral vein with huge dilatation or aneurysm-like structures |
4 |
where:
• ACA = anterior cerebral artery
• MCA = middle cerebral artery
• PCA = posterior cerebral artery
The final grade is determined by the pattern of the 4 parameters (as described on page 485).
Pattern of 4 Grades |
Final Grade |
all Grade 1 |
I |
3 Grade 1, 1 Grade 2 |
I-II |
2 Grade 1, 2 Grade 2 |
II |
1 Grade 3, 3 Grades 1 and/or 2 |
II-III |
2 Grade 3, 2 Grades 1 and/or 2 |
III |
<1 Grade 4, 3 others> |
III-IV |
<2 or more Grade 4, others> |
IV |
Operative morbidity increased with the final grade. Operative mortality was only seen with Grade III-IV and Grade IV lesions.
Final Grade |
Operative Morbidity |
I |
0% |
I-II |
0% |
II |
0% |
II-III |
17% |
III |
20% |
III-IV |
80% |
Specialty: Neurology