抄録
Microsurgical anatomy of skull base surgeries for aneurysms of the vertebral and basilar artery were studied using 3 cadavers treated by arterial and venous injection of the mixture of silicon with dye and barium sulfate. The suboccipital and lateral suboccipital approach (LSOA) are useful for VA-PICA and VA union aneurysms that are located laterally. Extradural resection of the jugular tubercle is necessary for approach to midline VA aneurysms. For this procedure, an emissary vein in the condylar fossa is a key anatomical landmark. For lower BA trunk aneurysms, the presigmoid retrolabyrinthine approach (PRA) via the Trautmann's triangular space is useful. This approach, however, does not permit enough working space to access aneurysms between Vth, VIIth-VIIIth and XIth nerves. Additional division of the sigmoid sinus, which might be risky in some patients, and cerebellar tentorium to PRA, namely the retrolabyrinthine transsigmoid approach and combined supra- and infratentorial approach permit more space. The (subtemporal) transpetrosal approach might have some problems of a narrow working space (even with a severe retraction of the temporal lobe) and of a difficult exposure of the proximal parent artery. The petrosal approach (PA), which consists of PRA and division of the tentorium and superior petrosal sinus, permits both the subtemporal and suboccipital routes with a minimal brain retraction. PA or the combined approach of (L)SOA and PA might be useful for BA trunk and midline VA aneurysms such as our case, in which multidirectional viewing was allowed through a working space large enough for the aneurysmal clipping and observation of the distal VA or BA behind an aneurysm.
