Abnormal discharges from the temporal neocortex after selective amygdalohippocampectomy and seizure outcomes

Area of Science:

• Neurosurgery
• Epileptology
• Clinical Neuroscience

Background:

• Abnormal electrical discharges from the temporal neocortex are frequently observed postoperatively in patients with mesial temporal lobe epilepsy (MTLE) and hippocampal sclerosis (HS).
• The clinical significance of these residual discharges and the necessity for additional surgical interventions remain unclear.
• Selective amygdalohippocampectomy (SelAH) is a surgical option for drug-resistant MTLE with HS.

Purpose of the Study:

• To investigate the relationship between residual temporal neocortical discharges and seizure outcomes following selective amygdalohippocampectomy (SelAH) in MTLE patients with HS.
• To determine if additional procedures are required to eliminate residual spikes for improved seizure control.

Main Methods:

• Retrospective analysis of 28 patients with unilateral MTLE and HS who underwent transsylvian SelAH.
• Electrocorticography (ECoG) recorded from the temporal base and lateral temporal cortex pre- and post-resection.
• Evaluation of postoperative seizure outcomes using the Engel classification and correlation with residual spike counts.

Main Results:

• The overall postoperative seizure-free rate was 92.9%.
• No significant correlation was found between a decrease in spike count and seizure outcomes (p=0.9259).
• The absence or presence of residual spikes in the temporal neocortex did not significantly influence seizure outcomes (p=1.000).

Conclusions:

• Residual abnormal discharges in the temporal neocortex do not appear to negatively impact seizure outcomes after SelAH in MTLE with HS.
• Current evidence suggests that focusing on the removal of mesial temporal structures is sufficient.
• Additional surgical procedures to eliminate residual temporal neocortical spikes are not indicated for seizure relief in this patient population.