In Reply to: Case 0498_11 -- Management of massive pelvic AVM posted by Editor on April 02, 1998 at 14:04:13:
Large pelvic AVMs like this are some of the most difficult lesions I have ever had to face.
The authors have done an excellent job so far but obviously still have a persistent AVM, a problem I certainly have encountered in too many circumstances.
Specifically, the problems are (or can be):
1) Identifying the nidus. This is particularly important because the treatment needs to be directed at the nidus if effective therapy is to be delivered. In order to do this, it is usually necessary to perform extensive selective and superselective angiography (as was done in this case) so that the nidus is seen. I've seen some of these pelvic AVMs supplied by massively dilated gonadal arteries which actually were the prinicipal feeding vessels.
On another imaging note, I use MR exclusively for cross-sectional imaging and followup of these lesions and have pretty much abandoned CT.
2) Accessing the nidus. Most of the problems I've had involve my inability to get into the nidus from these branch vessels which in reality are only collaterals to the nidus and not the main avenues. Intranidal treatment in complex cases may actually involve direct puncture of the lesion after it is targeted by angiographic opacification.
3) Treating the nidus. I think that this case illustrates the extreme difficulty we still have in treating these lesions since it appears that despite the nice use of three sessions with alcohol, either the nidus has not been treated or it has only been partially treated and therefore has recruited a number of dollaterals which will only enlarge over time and produce the same hemodynamic problems.
What now for this lesion?
I think that looking at it critically with an eye to how best to access and treat the nidus is the thing that should be foremost here. I would perform MRI and careful selective angio of every vessel I could find in the region and then assess the best way into the AVM, be it direct puncture or transcatheter.