OBJECTIVE: Our study aimed to evaluate the functional outcome and the risk of postoperative remnant in patients with rAVM after microsurgical treatment. METHODS: This is a retrospective of 139 consecutive patients operated for a rAVM between 2002 and 2012 in our institution. The age at diagnosis and the WFNS score were recorded for each patient before treatment. All patients were re-evaluated 3 months after treatment using mRS scale. Conventional angiography was performed in the first 2 postoperative weeks and then a year later to detect any remnant or recurrence. RESULTS: The mean age at diagnosis was 30.8 years (range 4-69 SD: ±5) and 44 patients had an age at diagnosis <18 yo. The mRS score 3 months after treatment was ≤2 in 104 patients (83%). Predictive factors of good functional outcome were age at diagnosis <25 yo, initial WFNS score ≤ 2, SPM grade ≤ 2 and absence of acute hydrocephalus (p<0.05). Complete obliteration was obtained in 123 patients (89.5%) after the first microsurgical treatment. Early postoperative conventional angiography revealed a rAVM remnant in 16 patients (10.5%). Late conventional angiography showed a recurrence in 6 patients (4.5%). All of them were <18 yo. Predictive factors of postoperative rAVM remnant were an initial WFNS score>2, SPM grade>2 and preoperative evaluation limited only to CT angiography in emergency situation (p<0.05). CONCLUSIONS: Functional outcome after microsurgical treatment was good in 83% of patients with rAVM. Good results were also recorded in 28% of patients with poor initial neurological status and severe intracerebral hemorrhage, which required immediate surgery. In case of remnant, a further treatment should be decided in a true multidisciplinary discussion to protect the patient from any rebleeding.