Insular Involvement in Cases of Epilepsy Surgery Failure

Abstract

Background: Epilepsy surgery failure is not uncommon, with several explanations having been proposed. In this series, we detail cases of epilepsy surgery failure subsequently attributed to insular involvement. Methods: We retrospectively identified patients investigated at the epilepsy monitoring units of two Canadian tertiary care centers (2004–2020). Included patients were adults who had undergone epilepsy surgeries with recurrence of seizures post-operatively and who were subsequently determined to have an insular epileptogenic focus. Clinical, electrophysiological, neuroimaging, and surgical data were synthesized. Results: We present 14 patients who demonstrated insular epileptic activity post-surgery-failure as detected by intracranial EEG, MEG, or seizure improvement after insular resection. Seven patients had manifestations evoking possible insular involvement prior to their first surgery. Most patients (8/14) had initial surgeries targeting the temporal lobe. Seizure recurrence ranged from the immediate post-operative period to one year. The main modality used to determine insular involvement was MEG (8/14). Nine patients underwent re-operations that included insular resection; seven achieved a favorable post-operative outcome (Engel I or II). Conclusions: Our series suggests that lowering the threshold for suspecting insular epilepsy may be necessary to improve epilepsy surgery outcomes. Detecting insular epilepsy post-surgery-failure may allow for re-operations which may lead to good outcomes.

Implementation of a Morphological Filter for Removing Spikes from the Epileptic Brain Signals to Improve Identification Ripples

“…62% [ 1 , 2 , 35 , 37 , 38 ]. Each surgery is also a very invasive and risky procedure [ 1 , 2 , 8 , 37 , 38 , 39 , 40 ].…”

“…Additionally. around 40% of epilepsy-affected patients suffer its drug-resistant version, which significantly limits potential treatment methods [ 1 , 2 , 3 , 5 , 8 ]. It affects the life quality of people affected with it in a significant way, as the seizures occur unexpectedly and can cause various physical injuries or even death [ 6 , 9 , 10 , 11 , 12 , 13 , 14 ].…”

Temporal-insular spreading time in temporal lobe epilepsy as a predictor of seizure outcome after temporal lobectomy

“…[3,4] Some studies have revealed that insular involvement in mesiotemporal lobe epilepsies could explain some persistent seizures after anterior temporal lobectomy (ATL). [5,6] In these patients, insular involvement is considered a potential risk factor for surgical failures. [6][7][8] The insula and temporal lobe (TL) belong to the limbic system and have very close fiber connections.…”

“…[5,6] In these patients, insular involvement is considered a potential risk factor for surgical failures. [6][7][8] The insula and temporal lobe (TL) belong to the limbic system and have very close fiber connections. The symptoms evoked by insular cortex stimulation are similar to those observed during TL seizures.…”

“…[ 5 , 6 ] In these patients, insular involvement is considered a potential risk factor for surgical failures. [ 6 – 8 ]…”