Insular epilepsy surgery

Abstract

Since it was originally described nearly 70 years ago, insular epilepsy has been increasingly recognized and may explain failures after apparently well-planned operations. We review the history of awareness of the phenomenon, techniques for its assessment, and its surgical management. Insular epilepsy can mimic features of frontal, parietal, or temporal seizures. It should be considered when a combination of somatosensory, visceral, and motor symptoms is observed early in a seizure. Extraoperative intracranial recordings are required to accurately diagnose insular seizures. Stereo-electroencephalography (EEG) or craniotomy with implantation of surface and depth electrodes have been used successfully to identify insular onset of seizures. Surgical resection of an insular focus may be performed with good success and acceptable risk.

Pilot Study of Voxel-Based Morphometric MRI Post-processing in Patients With Non-lesional Operculoinsular Epilepsy

“…Because of the wealth of insular connections to surrounding lobes, the clinical manifestations of operculoinsular seizures are diverse (7,28). Therefore, the localization of the seizure onset zone in some cases can be quite difficult and this is also a major reason of some surgery failures (29)(30)(31).…”

“…Because of the above-mentioned reasons, stereo-EEG is often mandatory to determine the precise seizure onset zones of insular epilepsy, in particular when MRI proves to be negative (13,28,33). The frequently used techniques can be orthogonal, oblique, or a combination of both trajectories (6).…”

“…However, the report of the applications of MRI post-processing methods used in insular or operculoinsular epilepsy is relatively rare. As operculoinsular epilepsy is commonly MRI negative (28), the application of non-invasive examinations which can help improve the detection rate of the epileptogenic lesion appears to be more important.…”

Stereotactic thermocoagulation for insular epilepsy: Lessons from successes and failures

“…Increasing interest in insular epilepsy has emerged during the past decade from studies based on stereo‐electroencephalography (SEEG) methodology . SEEG techniques for implanting the insula safely have been developed, and there is growing evidence that SEEG is particularly effective in demonstrating insular seizure onset . However, the insula lies deep in the sylvian fissure, covered by eloquent frontal, temporal, and parietal opercula with a dense network of vessels.…”

“…[1][2][3][4][5][6][7] SEEG techniques for implanting the insula safely have been developed, [8][9][10][11][12][13] and there is growing evidence that SEEG is particularly effective in demonstrating insular seizure onset. [14][15][16] However, the insula lies deep in the sylvian fissure, covered by eloquent frontal, temporal, and parietal opercula with a dense network of vessels. This makes open surgical resection of the insula fraught with risk, despite some recent series reporting reasonable outcomes.…”