Si. Stiver et Cs. Ogilvy, Micro-arteriovenous malformations: Significant hemorrhage from small arteriovenous shunts, NEUROSURGER, 46(4), 2000, pp. 811-818
OBJECTIVE: Micro-arteriovenous malformations (AVMs) represent approximately
8 to 10% of surgically treated brain AVMs. We examined the clinical presen
tations, radiological features, principles of surgical resection, and facto
rs affecting outcomes for micro-AVM lesions.
METHODS: Twelve patients with micro-AVMs that had been treated by surgical
resection were retrospectively analyzed. The mean follow-up monitoring peri
od was 35 months (range, 2-76 mo). Outcomes, as assessed in follow-up visit
s and telephone interviews (using a questionnaire), were classified accordi
ng to the Glasgow Outcome Scale.
RESULTS: All 12 patients presented with intracranial hemorrhage, which was
intraparenchymal and superficially situated in 10 patients (83%) and intrav
entricular in 2 patients (17%). Hemorrhages were large (mean volume, 23 ml(
3); range, 1-58 ml(3)) and were associated with neurological deficits for 1
0 of 12 patients (83%). The identification of an arterialized draining vein
during surgery and stereotactic angiography greatly facilitated surgical l
ocalization of the lesions. One patient (8%) developed a mild permanent def
icit as a result of surgery. Although Glasgow Outcome Scale scores were exc
ellent for all except one patient, nine patients (75%) experienced long-ter
m neurological problems.
CONCLUSION: Micro-AVMs typically present with large hemorrhages and are ass
ociated with significant neurological deficits. If a superficial clot is pr
esent, surgical resection of the lesion is strongly advocated. The ultimate
clinical outcomes are determined primarily by deficits present after the i
nitial hemorrhaging episodes.