Aneurysms of spinal arteries associated with intramedullary arteriovenous malformations. II. Results of AVM endovascular treatment and hemodynamic considerations.

PURPOSE: To evaluate the changes occurring in spinal aneurysm (SA) size related to modification of endovascularly treated AVMs.
METHODS: Fourteen patients with an intramedullary AVM and associated SA underwent endovascular treatment of their AVM with particles. Embolization sessions numbered from one to 14 (mean five) in each patient.
RESULTS: Four patients had SAs with size changes mirroring those of the AVM with embolization: these decreased in size or disappeared after AVM reduction or cure and increased or recurred after AVM recanalization. A second group of patients had SAs that remained unchanged despite AVM changes (six of seven of these were in patients with metameric angiomatosis).
CONCLUSIONS: Results in the first group lend support to the hemodynamic theory of associated aneurysm formation. On the other hand, aneurysms that remained unchanged probably are not AVM flow-related and could be an expression of an extensive vascular disorder such as metameric angiomatosis; however, hemodynamic and developmental factors could be concurrent.