Introduction: Selective Amygdallohippocampectomy can be performed through various approaches for patients with mesial temporal lobe epilepsy. We favor the minimal access subtemporal amygdallohippocampectomy (MASAH) because it spares the lateral temporal structures which are violated by the trans-gyral approach and the connecting tracts to the frontal lobe which are violated by the trans-sylvian approach. We therefore wanted to document the cognitive outcomes after MASAH to determine if neurocognitive functions are indeed preserved by using this approach

Methods: A total of 46 patients who underwent subtemporal selective amygdalohippocampectomy (Right MASAH n=20, Left MASAH n=46) were compared by paired sample t-tests on preoperative and postoperative neuropsychological performance. Measures included the Wechsler Abbreviated Scale of Intelligence, Brief Visual Memory Test-Revised, Rey Auditory Verbal Learning Test, and Beck Depression Inventory-2.

Results: There were no differences on demographic variables between the right and left groups. Post-operative evaluation was conducted an average of 8.4 months following SAH. Seizure freedom was reported by 80.8% of the patients. Significant increase in verbal intellect was noted in the right MASAH group while other variables remained unchanged. The left MASAH group showed a significant increase in non-verbal intellect but no other significant changes.

Conclusions: Findings from this study indicate there are minimal changes in intellect and memory following right or left subtemporal MASAH for treatment of focal onset epilepsy. At a group level, improvement in aspects of intellectual functioning following selective resection may be related to a release of other cognitive functions or reduced seizure activity as previously reported by other researchers. Improved funtionality may be a result of sparing critical structures and connections by this approach. MASAH may be superior in neurocognitive preservation compared to other approaches for mesial temporal lobe epilepsy

Patient Care: Hopefully after attending this session, more surgeons will adopt the subtemporal approach for the treatment of mesial temporal lobe epilepsy, which should result in better neurocognitive outcomes for their patients.

Learning Objectives: By the conclusion of this session, participants will become aware of potential neurocognitive outcome advantages of the minimal access subtemporal approach for selective amygdallohippocampectomy

References: Little AS, Smith KA, Kirlin K, et al. J Neurosurg 111:1263-1274, 2009: Modifications to the subtemporal selective amygdallohippocampectomy using minimal-access technique:seizure and neuropsychiaic outcomes. Park TS, Bourgeois BF, Silbergeld DL, Dodson WE: J Neurosurg 85:1172-1176, 1996: Subtemporal transparahippocampal amygdallohippocampectomy for surgical treatment of mesial temporal lobe epilepsy: Technical note.