White fiber correlates of amygdalo-hippocampectomy through the middle temporal gyrus approach.

OBJECTIVE The white fiber and gross anatomy relevant for performing amygdalo-hippocampectomy through the middle temporal gyrus approach for mesial temporal sclerosis has been depicted by white fiber dissection. MATERIAL AND METHODS Three previously frozen and formalin fixed cerebral hemispheres were studied. The Klingler's method of fiber dissection was used to study the anatomy. The primary tools used were hand-made wooden spatulas, forceps and microscissors. The anatomy of the amygdala and hippocampus and the landmarks for performing the disconnection during epilepsy surgery are presented. The white fibers at risk during the middle temporal gyrus approach were studied. RESULTS The white fiber tracts at risk during the middle temporal gyrus approach for epilepsy surgery are the fibers of the inferior fronto-occipital fasciculus, the temporal extension of the anterior commissure, the Meyer's loop of the optic radiation and the uncinate fasciculus. Based on our anatomical dissections we present a novel entry point into the temporal horn potentially minimizing injury to the fibers of the sagittal stratum. We also propose novel landmarks to perform the amygdala disconnection in mesial temporal sclerosis. CONCLUSION The middle temporal gyrus is a commonly used approach to perform temporal lobectomy and amygdalo-hippocampectomy for patients with mesial temporal sclerosis. The anatomy relevant to the approach as presented will aid while performing epilepsy surgery.