Background and purpose: The aim of this study was an analysis of early and late results of the microsurgical treatment of arteriovenous malformations (AVM) located supratentorially and factors that may influence the outcome.
Material and methods: 88 consecutive patients operated on in the years 1983-2000 for supratentorial AVM located were included in a retrospective analysis. All patients underwent microsurgical selective removal of AVM without prior embolization. The outcome was assessed on the day of discharge according to the Glasgow Outcome Scale (GOS) and at least 6 months after surgery according to the Karnofsky Scale (KS).
Results: A satisfactory outcome (GR+MD in GOS) was achieved in 92%. A severe deficit appeared in 4.5% and 3 (3.4%) patients died. The only factor influencing satisfactory outcome was low grade of AVM (I-II) in the Spetzler-Martin scale (p<0.0001). Factors influencing the excellent outcome (GR in GOS) are: size of AVM<3 cm (p=0.02), non-eloquent location (p=0.001) and exclusively superficial venous drainage (p=0.04). There was no case of deterioration in the late period. In 3/4 of patients discharged with deficit, a significant improvement was observed: a mild deficit withdrew in 13 of 17, and a severe deficit withdrew in 3 of 4. A satisfactory outcome in final assessment (KS>70%) was achieved in 95.5%, severe disabling deficit (KS 50%) remained in 1.1%.
Conclusions: Results of the surgical treatment of AVM are satisfactory, especially in I and II grade of the Spetzler-Martin scale. In these cases microsurgical removal should be the method of choice, because immediately after treatment the risk of further hemorrhage is eliminated. Postoperative deficits withdraw during weeks or months in most cases and the final satisfactory result was achieved in 95% of patients.