Removal of occipital arteriovenous malformations with sparing of visual fields.

Two patients with occipital lobe arteriovenous malformation (AVM) underwent two-stage resection of their lesions. The intervals between operations were eight and 12 days. Prior to surgery, the patients had normal neuro-ophthalmologic examination results and both experienced a reversible homonymous hemianopsia after the initial, partial resection of the AVM. Frequent seizures with visual hallucinations developed in the early postoperative period, with gradual improvement of the visual field defect. The pattern and duration of visual disturbances and the nature of the visual field defects in each patient had similar characteristics. The second operation with complete resection of the AVMs left normal visual fields.