Does resection of the medial temporal lobe improve the outcome of temporal lobe epilepsy surgery?
OBJECTIVE
Surgical removal of the hippocampus is the standard of care of patients with drug-resistant medial temporal lobe epilepsy (MTLE). The procedure carries a success rate of approximately 75%, but the reasons that some patients fail to achieve seizure control after surgery remain inexplicable. The question of whether the resection of medial temporal lobe structures in addition to the hippocampus would influence the surgical outcome in patients with MTLE was examined.


METHODS
We conducted voxel-based statistical analyses of postoperative high-resolution MRI of MTLE patients who underwent anteromedial temporal resection. We applied a cost function transformation of the resection maps for each patient to a common set of spatial coordinates, and we analyzed the contribution of histologically distinct segments of the medial temporal lobe cortex to the surgical outcome. We also performed a voxel-wise mapping of surgical outcome to the temporal lobe.


RESULTS
We observed that the extent of hippocampal removal was associated with better outcomes. However, when the resection of the hippocampus was combined with the resection of the medial temporal lobe, specifically the entorhinal cortex, a greater likelihood of higher seizure control after surgery was found.


CONCLUSIONS
Based on this finding, it is possible that the efficiency of the surgical treatment of MTLE can be improved by adjusting the procedure to include the resection of the entorhinal cortex, in addition to the resection of the hippocampus.
Bonilha
Leonardo
L
Department of Neuropsychiatry, University of South Carolina, Columbia, South Carolina, USA.
Yasuda
Clarissa Lin
CL
Rorden
Chris
C
Li
Li M
LM
Tedeschi
Helder
H
de Oliveira
Evandro
E
Cendes
Fernando
F
D000293:Adolescent; D000328:Adult; D000927:Anticonvulsants / Q000494:pharmacology; D001931:Brain Mapping; D004351:Drug Resistance; D018728:Entorhinal Cortex / Q000601:surgery; D004833:Epilepsy, Temporal Lobe / Q000601:surgery*; D006624:Hippocampus / Q000601:surgery; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods; D013702:Temporal Lobe / Q000601:surgery*; D016896:Treatment Outcome
D000927:Anticonvulsants