Subtemporal approach - Venous drainage and surgical anatomy

Because the temporal lobe extends deeply into the middle cranial fossa anteriorly, the procedure of the subtemporal approach should be modified so as to avoid damaging the brain and the cortical veins by compression with retractors. To minimize compression damage to the temporal lobe it is necessary to perform the craniotomy along the middle cranial fossa, and to remove the zygomatic arch for supratentorial lesions, and to remove the petrous pyramid for infratentorial lesions. An extradural approach is useful as a means of preventing damage to bridging veins including Labbe's vein, but because the superior petrosal sinus and the tentorium are transected in the procedure by the anterior transpetrosal approach, the drainage pathways of the superficial sylvian vein (especially the sphenobasal vein and the sphenopetrosal vein) should be checked preoperatively. In this article we outline the surgical anatomy of the middle cranial fossa required for the subtemporal approach and variations in the venous drainage of the superficial sylvian vein, and then we describe the treatment of petroclival lesions by the anterior transpetrosal approach.