The authors conducted a long-term follow-up study of 168 patients to define the natural history of clinically unruptured intracranial arteriovenous malformations (AVM's). Charts of patients seen at the Mayo Clinic between 1974 and 1985 were reviewed. Follow-up information was obtained on 166 patients until death, surgery, or other intervention, or for at least 4 years after diagnosis (mean follow-up time 8.2 years). All available cerebral arteriograms and computerized tomography scans of the head were reviewed. Intracranial hemorrhage occurred in 31 patients (18%), due to AVM rupture in 29 and secondary to AVM or aneurysm rupture in two. The mean risk of hemorrhage was 2.2% per year, and the observed annual rates of hemorrhage increased over time. The risk of death from rupture was 29%, and 23% of survivors had significant long-term morbidity. The size of the AVM and the presence of treated or untreated hypertension were of no value in predicting rupture.

The results of temporal lobectomy for medically refractory seizures are analyzed in 29 boys and 21 girls with a mean age of 15.8 years. The average age at onset of seizures was 7.5 years, and the time between onset and surgery averaged 8.3 years. Postoperatively, 27 patients (54%) were seizure-free, 12 patients (24%) had only occasional auras without loss of consciousness, five patients (10%) had fewer seizures, and six (12%) were unchanged. Therefore, 78% were essentially seizure-free and 88% benefited significantly from the operation. There was no significant change in the Wechsler Intelligence Scale scores before and after surgery; however, the shorter the time between seizure onset and surgery, the greater the likelihood of improvement in verbal and perceptual intelligence quotient. Social outcome was significantly improved, and a large percentage of patients were either in school or actively employed. Early consideration of temporal lobectomy in children with medically refractory seizures is recommended.

The authors report their experience with the use of saphenous vein bypass grafts for treating advanced occlusive disease in the posterior circulation (77 patients, all of whom had failed medical management and showed severe ischemic symptoms), deteriorating patients with giant aneurysms of the posterior circulation (nine patients), progressive ischemia in the anterior circulation (26 patients, none of whom had a normal examination), and giant aneurysms in the anterior circulation (20 patients, all of whom presented with mass effect or subarachnoid hemorrhage). Graft patency in the first 65 cases treated was 74%. However, after significant technical changes of vein-graft preparation and construction of the proximal anastomosis, patency in the following 67 cases was 94%. Excellent or good results (including relief of deficits existing prior to surgery) were achieved in 71% of patients with advanced occlusive disease in the posterior circulation, 44% of those with giant aneurysms of the posterior circulation, 58% of those with ischemia of the anterior circulation, and 80% of those with giant aneurysms of the anterior circulation. Mean graft blood flow at surgery in the series was 100 ml/min for posterior circulation grafts and 110 ml/min for anterior circulation grafts. Experience to date indicates that this is a useful operation, and is particularly applicable to patients who are neurologically unstable from advanced intracranial occlusive disease in the posterior circulation or with giant aneurysms in the anterior circulation. The risk of hyperfusion breakthrough with intracerebral hematoma restricts the technique in patients with progressing ischemic symptoms in the anterior circulation, and the intolerance of patients with fusiform aneurysms in the posterior circulation to the iatrogenic vertebrobasilar occlusion limits the applicability of this approach to otherwise inoperable lesions in that system.

No abstract

✓ Decreased memory and learning efficiency may follow left temporal lobectomy. Debate exists as to whether the acquired deficit is related to the size of the surgical resection. This study addresses this question by comparing changes in cognitive performance to the extent of resection of both mesial temporal structures and lateral cortex. The authors retrospectively reviewed 47 right-handed patients who underwent left temporal lobectomy for medically intractable seizures. To examine the effects of the extent of mesial resection, the patients were divided into two groups: those with resection at the anterior 1 to 2 cm of mesial structures versus those with resection greater than 2 cm. To examine the effects of the extent of lateral cortical resection, patients were again divided into two groups: those with lateral cortex resections of 4 cm or less versus those with resections greater than 4 cm. Statistical analyses showed no difference in cognitive outcome between the groups defined by the extent of mesial resection. Likewise, no difference in cognitive outcome was seen between the groups defined by the extent of lateral cortical resection. Associated data analyses did, however, reveal a negative correlation of cognitive change with patient age at seizure onset. These results showed that the neurocognitive consequences of extended mesial resections were similar to those of limited mesial resections, and that the neurocognitive consequences of extended lateral cortical resections were similar to those of limited lateral cortical resections. The risk of cognitive impairment depends more on age at seizure onset than on the extent of mesial or lateral resection.