The Tale of the Residual Tail: Insights From Continuous Intracranial Monitoring From Post-Hippocampectomy Dynamics

Subtotal hippocampal resection can leave residual hippocampal tissue, yet the immediate postoperative electrophysiologic evolution of such remnants is unknown. We describe a patient with drug-resistant temporal lobe epilepsy in whom a hippocampal remnant was continuously monitored using a responsive neurostimulator (RNS) following subtotal hippocampal resection. Postoperative electrocorticography demonstrated persistent electrographic status epilepticus for 3 days, followed by a transient 5-day quiescent period and delayed recurrence of electrographic and clinical seizures on postoperative day eight. This case provides rare, real-time insight into the dynamic temporal evolution of residual hippocampal excitability after surgery and offers a potential mechanistic explanation for delayed postoperative seizure recurrence following incomplete hippocampal resection.