High-grade arteriovenous malformations and their management.

The aim of this study was to compare operatively and non-operatively managed high-grade arteriovenous malformations (AVMs) and to identify risk factors for surgical morbidity. Three hundred and ninety-one consecutively enrolled patients with AVMs were graded using the Spetzler Martin grading scheme. Forty-six of these patients had grade 4 or 5 AVMs. Twenty-nine patients underwent surgery and 17 were conservatively managed. During an average of 33 months follow-up the non-operative group experienced a decline in function in 27% of cases followed. These deteriorations were due to haemorrhage, progressive neurological deficits and seizures. In the surgical group completing treatment there was a mortality and morbidity impacting on self-care of 15%. In those without deep perforating arterial supply the morbidity was 10% and with deep perforating arterial supply or deep meningeal recruitment there was a combined morbidity and mortality of 44%. This difference in outcome was statistically significant (P<0.01). We conclude that high-grade AVMs have a high operative morbidity. However, these lesions often have a poor natural history and with careful selection (based on the presence or absence of deep perforating arterial supply) a group can be selected that benefits from surgery. Grade 4 and 5 AVMs with supply from lenticulostriate, choroidal, thalamic deep perforating arteries or deep meningeal recruitment may be best treated conservatively or possibly by multimodality treatment utilising radiotherapy and embolisation combined with surgery.