Abstract
The authors report the case of a 23-year-old male with a parasplenial arteriovenous malformation (AVM). In March, 1993, he had suffered a sudden intraventricular hemorrhage, and two months after this episode, he sought medical help. Neurologically, the patient only manifested an upper half peripheral visual field defect on ophthalmological inspection. Angiography, however, revealed a small AVM of the parasplenial region. This AVM was being fed by the lateral posterior choroidal artery, and was draining into the great vein of Galen. Thus, in May, 1993, surgery was performed via a right occipital craniotomy with the patient in a lateral-semiprone position. The posterior interhemispheric approach was used to expose the AVM. Postoperatively, the patient showed no neurological deficits and, on ophthalmological inspection, showed no visual defects. Further, angiography and CT scans confirmed the complete removal of the AVM. The advantages of using the posterior interhemispheric approach in a lateral-semiprone position are as follows : 1) there are no visual field defects ; 2) it provides a good orientation ; 3) the operative view is wide ; 4) retraction is mild because the brain gravitates toward operative side : 5) the positioning is suitable for both the operator and the patient ; and, 6) the risk of an air embolism is less. For these reasons, the authors emphasize the usefulness of the lateral-semiprone position when using the posterior interhemispheric approach. They also discuss the complications, i. e., an air embolism and limbic seizures, that occurred in this case.
