定位脳手術の破壊法に関する研究

EXPERIMENTAL AND CLINICAL STUDIES ON THE DESTRUCTION METHOD IN STEREOTAXIC SURGERY

I．緒言

　1947年Spiegel　＆　Wycisがはじめて人脳に対する手術法の革命ともいうべき定位脳手術法の第1歩を印して以来，諸家の努力により破壊装置や破壊方法さらに破壊部位等の研究や改善が試みられ，現在では本法による治療適応の疾患も多岐にわたるに至つた。

　現在までの破壊方法は多種多様であり，破壊巣およびその周辺の変化についての検討は従来破壊巣の組織学的な検索すなわち主として器質的な面から行なわれてきたが，筆者らは破壊法として現在最も多く使用されているOil-Wax注入および高周波破壊法によつて実験的に破壊巣を形成し，この破壊巣ならびにその周辺部の変化について脳内局所impedansおよび深部脳波の記録による機能的な面からの検討を行ない，さらに臨床的な観察も加えていささかの知見をえたので報告する。

In cats with electrodes permanently implanted in the brain, Oil-Wax injection aimed at the pallidum as well as the destruction by means of high fre-quency current aimed at the thalamus were carried out stereotaxically. Changes occurring in the de-stroyed site and in its surroundings on that occasion were followed with the lapse of time regard to both aspects of local impedance of the brain and the depth electroencephalograms, and after sacrificing the animals observation was made macroscopically and histologically on the areas concerned. Further-more, with the human brain local impedance fluctua-tions as well as changes of the depth EEG caused by destruction with high frequency current were investigated.

Moreover, on the basis of the data obtained from the patients with parkinsonism to whom the Oil-Wax injection or the destruction with high frequency current aimed at the same target point was applied, a comparison was made between the former and the latter as a destruction method in stereotaxic surgery.

1) The present comparative study revealed that in both the Oil-Wax injection and the destruction with high frequency current, changes in the im-pedance fluctuation were remarkable, but those in the EEG were not so evident.

2) Although changes in the impedance fluctuation due to Oil-Wax injection were recognizable for a while after injection, it gradually returned to the state before injection. On histological examination it was found that this finding was in accord with the fact that the repair of destroyed tissues was advancing gradually.

3) On the contrary, as regards the changes in the impedance fluctuation due to destruction with high frequency current the impedance fluctuation returned, in the peripheral part, to the state before destruction in the course of time gradually, whereasit did not appear even 3 weeks after destruction. From the histological point of view it proved that there existed an irreversible destruction in the cen-tral part.

4) So far as the above-mentioned cases of par-kinsonism to which either the Oil-Wax injection or the destruction with high frequency current aimed at the same target point were concerned, it was ascertained that although in all these examined marked effects could be demonstrated for a while from just after operation. However recurrence oc-curred in the former and, in contrast, in the latter there was almost no recurrence.

From these results it can be concluded that the method of destruction by means of high frequency current represents an ideal on to destroy the brain tissues for stereotaxic surgery as compared with the method of Oil-Wax injection.