Studv on microsurgical anatomv and related operative approach for the basilar artery

Objective To explore the scope of the bifurcation of basilar artery and compare difference of these operative approaches via pterional approach and subtemporal approach,and provide reference for the microsurgery for BA apex aneurysm.Method Ten(20 sides)adult cadaveric specimens were studied by using the subtemporal approach and pterional approach under the microscope,respectively.We observed and measured the relationship among the important neurovascular structures,and described the exposure scope of the bifurcation of basilar artery and compared difference of related operative approaches.Results The pterional approach can provide excellent exposure for the posterior part of the sellar region and BA bifurcation via optic nerve - ICA space( space Ⅱ) under the angle 30°.The visibility of the interior side was more and more bigger,but the lateral side was blocked by temporal lobe in space Ⅲ under different visual angles from 0° to 60°,and the area of space Ⅲ under angle 45°was the biggest.The subtemporal approach can provide wide exposure for the base of the middle cranial fassa and perforating arteries arising from BA bifurcation and P1 segment.The exposure of the BA apex can be increased after cutting tentorium,and a wider scope of exposure was obtained to the lateral aspect of the brainstem.Conclusions Compared with space Ⅱ,exposure of space Ⅲ had great advantage.The subtemporal approach has advantages such as shorter distance of operation,bigger straight visual angle.We can observe the perforating branches arising from BA bifurcation and P1 segment though lateral wider visual field,when clipping the aneurysm which directed backward. Key words: Basilar artery;  Intracranial aneurysm;  Dissection;  Neurosurgical procedures