Microsurgical and endoscopic approaches to the basilar bifurcation: Quantitative comparison of combined pterional/anterior temporal and orbitozygomatic extended approaches

To determine the most effective route to the upper third of the basilar art ery, 10 cadaver dissections were performed comparing the exposure gained us ing the combined pterional/anterior temporal approach and the orbitozygomat ic extended approach. Endoscopic evaluation through an eyebrow incision in each dissection helped determine whether any advantage was conferred by the cranial base approach. This also served to assess the benefit of using the endoscope as an adjunct to open procedures in evaluating the opticocarotid and retrocarotid routes to the basilar artery. The results of cadaveric di ssections suggest that compared with the exposure afforded by the combined pterional/anterior temporal approach, the orbitozygomatic extended approach yields an increase of 8 cm in the anteroposterior axis and 10 cm in the su peroinferior axis. Furthermore, as expected, the increases in visibility we re directed anteriorly and posteriorly. When employed through the craniotom y site during aneurysm clipping, endoscopy was found to be potentially usef ul in assessing the contralateral elements of the upper basilar complex.