5.3.15\ Selective

Amygdalohippocampectomy

5.3.15.1\ Discussion

Selective amygdalohippocampectomy is a limited form of temporal lobectomy, which can be performed via transcortical, subtemporal, or transsylvian approaches or via laser ablation. Resection or laser ablation of at least some portions of the

a

amygdala, anterior hippocampus, parahippocampal gyrus, and the subiculum is performed (Fig. 5.64). However, secondary encephalomalacia in the remaining portions of the temporal lobe is frequently observed due to Wallerian degeneration. Furthermore, injury to critical adjacent structures, such as the lateral geniculate nucleus with associated vision loss, can nevertheless occur with this selective procedure (Fig. 5.65).

b

Fig. 5.64  Amygdalohippocampectomy. Axial (a) and coronal (b) T1-weighted MR images show a small resection cavity (arrows) in the left medial anterior temporal

lobe structures, including the amygdala and hippocampus. The lateral portions of the temporal lobe are intact

Fig. 5.65  Visual pathway injury from laser ablation amygdalohippocampectomy. The patient presented with new coronal T2-weighted MRI (a) shows the site of ablation involving the left hippocampus, as well as the adjacent temporal stem and lateral portion of the thalamus

(encircled). Indeed, there is high FLAIR signal (b) and restricted diffusion (c) and interruption (d) of a portion of the left optic radiations and lateral portions of the thalamus (arrows), as well as the pulvinar (arrowheads)