Aim:For cerebral arteriovenous malformations (AVMs) involving language areas, right-sided language lateralization on functional magnetic resonance imaging (fMRI) has been reported, which is regarded as language cortex reorganization. The authors attempt to study if this right-sided language lateralization affects postoperative language outcome.Material and Methods:Clinical and imaging data of 43 right-handed AVM patients who underwent preoperative fMRI were retrospectively reviewed. All lesions involved the language cortex, with the Broca area involved in 13 patients and the Wernicke area involved in 30 patients. Lateralization indices (LI) of BOLD signal activations were calculated to determine language lateralization. All patients underwent craniotomy and total resection. Western aphasia battery (WAB) was used to evaluate language functions preoperatively, 1-2 weeks after surgery and 6-30 months after surgery.Results:On preoperative fMRI, right-sided lateralization was observed in 18 patients (41.9%, R Group), including 3 with right-sided lateralization in the Broca area alone, 14 in the Wernicke area alone, and 1 in both areas. The other 25 patients were non-right-sided lateralized (NR Group). One week after surgery, 7 patients in the R Group (38.9%) and 11 patients in the NR Group (44.0%) had language function deterioration, and no significant difference was found (p=0.983). At long-term follow-up, 3 patients in the R Group (16.7%) and 4 patients in the NR Group (16.0%) still had aphasia, and no significant difference was observed, either (p=1.000).Conclusion:Although right-sided lateralization on fMRI might suggest language cortex reorganization, it is not a factor predicting better postoperative language outcome for AVM patients.