Treatment of Callosal Arteriovenous Malformations

ABSTRACT

OBJECTIVE: To establish management strategy and to improve outcome of callosal arteriovenous malformations(AVMs), forty-six consecutive cases hospitalized from 1984 to 2001 are analyzed. METHODS: Clinical and radiologic files were reviewed. Average follow-up period was 20.3 months in microsurgery group, and 28.2 months in radiosurgery group. RESULTS: The resection rate of microsurgery was considered total in 12 patients(85.7% ), subtotal 2(14.3%). The final clinical outcome of microsurgery was good in 13 patients(92.8%), fair in 1(7.2%). One patient with splenial lesion had postoperative disconnection syndrome. Initial insults and hemodynamic complications were the major cause of an unfavorable outcome. In radiosurgery the complete regression of nidus was considered in 16 patients(51.6%), partial shrinkage in 13(41.9%), and no response in 2(6.5%). The clinical outcome of radiosurgery was good in 26 patients(83.9%), fair in 3(9.75%), and poor in 2(6.5%). Rebleeding during the latency period(3 patients), radiation necrosis(1 patients) and initial insults(1 patients) were the major cause of postradiosurgery morbidity. Rebleeding during the latency period occurred in 3 patients(9.7%). Two lesions were in the splenium, and one lesion in the body of corpus callosum. All lesions were larger than 3cm in diameter. Two of them occurred during the second year, and the rest one during the third year of latency period. CONCLUSION: Microsurgery, which eliminates the risk of bleeding immediately, is referred for callosal AVMs. Radiosurgery is another effective treatment modality for splenial lesions with large bridging veins that interfere with microsurgical approach, and combined endovascular treatment would be strongly recommended for the splenial lesions larger than 3cm in diameter that has higher risk of hemorrhage during the latency period.