[(12)Revascularisation and aneurysms of the posterior circulation]

This is the last article, namely, the twelfth topic, in the series "personal view and historical backgrounds of operative neurosurgery." In this article, revascularisation and aneurysms of the posterior circulation are thematized. As an example for classic posterior circulation EC-IC bypass, a case of basilar stenosis is presented. The stenosis turned out to occlusion by good patency of the STA-SCA bypass, and although it initially showed clinical improvement, it manifested as severe pontine infarction several months later. Considerations on such malignant conversion are discussed together with probable prevention methods. Other revascularisation methods involving the supracerebellar transtentorial approach(SCTTA), namely, OA-SCA or OA-PCA bypass in the sitting position, are presented and their advantages and disadvantages are discussed. As for posterior circulation aneurysms, the role of SEAC and its advantages for treating basilar bifurcation aneurysms are presented and discussed. SCTTA and SAHE approach are presented as special approaches for other PCA aneurysms, and their advantages of getting the parent artery P2 for P2-P3 junction aneurysm in the latter was emphasized. The advantage of a sitting position for revascularisation or aneurysm surgeries, cleanliness of the operative field in cases of premature rupture or clipping procedure, and through the bush of lower cranial nerves are also discussed.