Intraoperative anatomic landmarks for resection of the amygdala during medial temporal lobe surgery

To establish reliable gross landmarks for resecting the amygdala intraoperatively, especially during anteromedial temporal lobectomy and amygdalohippocampectomy for epilepsy surgery. Reliable landmarks would allow its safe and complete resection as well as its potential en bloc removal for detailed electrophysiological and histopathological analyses.

Ten adult cadavers (20 sides) were used. Two adjacent anatomic structures were identified: the bifurcation of the middle cerebral artery (MCA point) and the entry point of the anterior choroidal artery (AChoA) at the anterior origin of the choroid plexus into the temporal horn (inferior choroidal point referred to as the AChoA point). Following removal of the brain tissue inferior and anterior to the imaginary line connecting these 2 anatomic landmarks, cross sectional histopathological analysis of the remaining temporal and frontal lobes was performed to verify the presence or absence of any nervous tissue belonging to the amygdala complex.

In all 20 sides, the entire amygdala complex was found anterior and inferior to the transection made along the MCA-AChoA line. No apparent injury to the adjacent striatum was discovered.

Two easily identifiable points, including the middle cerebral artery bifurcation and the inferior choroidal point, may define a line that reliably disconnects the amygdala complex from the remaining temporal and frontal lobes. These landmarks may assist in resection of the amygdale while preserving important adjacent structures, including the striatum.