[Microsurgical anatomy and surgical approach of the ambient cistern]

to describe detailed anatomy and compare four surgical approach of the ambient cistern, to assist in the process of conceptualizing a reliable surgical approach to allow for a successful course of surgery.

The microsurgical anatomy of the ambient cistern and four surgical approach was studied in 12 formalin-fixed brain specimens (24 hemispheres). Four simply formalin-fixed, the cerebral arteries of eight brain specimens were perfused with colored silicone, and they were dissected with the aid of an operating microscope. Special attention was paid to the anatomic structures limiting visualization in each approach.

The ambient cistern extends from the posterior margin of the crural cistern to the lateral edge of the midbrain colliculi, and round the lateral surface of the upper portion of the brainstem; The ambient cistern mainly contained P(2) segment of the posterior cerebral artery, superior cerebellar artery, anterior choroidal artery, basal vein and trochlear nerve. The subtemporal approach allow for excellent exposure of the lower half of the ambient cistern, the vein of Labbé and the parahippocampal gyrus obstacle to exposure through this approach; The transtemporal transchoroidal approaches exposed the upper half of the ambient cistern of non-dominance hemisphere, its major drawback is the need to perform a corticectomy in the temporal lobe. In addition, the vein of Labbé extended far enough anteriorly to limit the cortical incision in the temporal lobe. The transinsular transchoroidal exposed the anterior upper half of the ambient cistern. Its major disadvantage is damage the temporal stem, the longer the inferior limiting sulcus, the shorter the incision, the better for preservation the temporal stems; The occipital transtentorial approaches exposed the posterior lower half of the ambient cistern, the parahippocampal gyrus also blocked to exposure through this approach.

Surgical approaches to lesions of the ambient cistern must be tailored to the site of the pathological findings. Position of the vein of Labbé, and the midpoint of the rounded medial edge of the parahippocampal gyrus, is key to determine Surgical Approach.