大脳基底核・視床のAVMの手術適応と問題点

抄録

Arteriovenous malformations (AVMs) of the basal ganglia represent a special group of malformations because of the difficulties of their resection. For better understanding the surgical indication, the outcome of 28 cases of basal ganglia AVMs were retrospectively analyzed. Out of the 28 cases, 13 patients had their AVMs surgically removed. The other 15 cases were conservatively treated because of the large size of the nidus, the particular location of the nidus, having no history of hemorrhage, etc. In the conservatively treated group, 10 patients had a history of hemorrhage. Of the 10 patients with hemorrhage, 8 cases had rebleeding. Looking at the follow-up results of these 8 patients, 5 died, one was bed-ridden, and only 2 were working. Thus, the prognosis of patients with hemorrhage is poor, if conservatively treated.
In 13 patients who had surgical removal of the AVM, the effects of surgery on motor function were evaluated. Six patients showed hemiparesis before the operation. Of these 6 patients, only one improved after the operation, and 5 remained unchanged. However, the follow-up results showed that 4 are working, one is caring for herself, and one is bed-ridden. Based on these results, it can be said that the life of patients with large intracerebral hematoma can be saved by evacuating the hematoma and removing the AVM. Furthermore, motor weakness can also be improved to some extent by rehabilitation. Regarding the 7 patients with hemorrhage and no paresis, 3 deteriorated after the operation; two of these had renticular AVMs and one had a thalamic AVM. Fortunately, one of these patients is now working, and the other two are caring for themselves. Surgical indication of renticular AVM patients, who have had a history of hemorrhage but no neurological deficits, must be carefully decided.
Speech disturbance occurred after the operation in 5 out of 6 dominant-side AVMs. Except for one case in which the internal capsule was damaged by the operation, post-operative speech disturbance completely disappeared within 1 year. The relationship between the surgical approach and the post-operative visual field defects was also evaluated. Out of 5 cases operated on by the transtemporal approach, 4 showed post-operative visual field defects. Such post-operative visual field defects did not improve to a great extent.
Based on these results, the following conclusions were drawn: 1) Prognosis of the patients with a history of hemorrhage was poor if conservativey treated. Such patients should somehow be treated to prevent the second hemorrhage. 2) Patients with large intracerebral hematoma should be operated on. 3) Certain patients with hemorrhage but without deficits can be safely operated on, if the patient is young, the nidus is small and is located in the caudate nucleus or the thalamus. 4) Postoperative speech disturbance will improve within one year after the operation. 5) Persisting visual field defects were produced in most cases of the transtemporal transventricular approach.