Intracranial EEG and laser interstitial thermal therapy in MRI-negative insular and/or cingulate epilepsy: case series

OBJECTIVE The goal of this study was to assess the success rate and complications of stereo-electroencephalogra-phy (sEEG) and laser interstitial thermal therapy (LITT) in the treatment of nonlesional refractory epilepsy in cingulate and insular cortex. METHODS The authors retrospectively analyzed the treatment response in 9 successive patients who underwent insu-lar or cingulate LITT for nonlesional refractory epilepsy at their center between 2011 and 2019. Localization of seizures was based on inpatient video-EEG monitoring, neuropsychological testing, 3-T MRI, PET scan, magnetoencephalog-raphy scan, and/or ictal SPECT scan. Eight patients underwent sEEG, and 1 patient had implantation of both sEEG electrodes and subdural grids for localization of epileptogenic zones. LITT was performed in 5 insular cases (4 left and 1 right) and 3 cingulate cases (all left-sided). One patient also underwent both insular and cingulate LITT on the left side. All of the patients who underwent insular LITT as well as 2 of the 3 who underwent cingulate LITT were right-hand domi-nant. The patient who underwent insular plus cingulate LITT was also right-hand dominant. RESULTS Following LITT, 67% of the patients were seizure free (Engel class I) at follow-up (mean 1.35 years, range 0.6- 2.8 years). All patients responded favorably to treatment (Engel class I-III). Two patients developed small intracranial hem-orrhages during the sEEG implantation that did not require surgical management. One patient developed a large intracra-nial hemorrhage during an insular LITT procedure that did require surgical management. That patient experienced aphasia, incoordination, and hemiparesis, which resolved with inpatient rehabilitation. No permanent neurological deficits were noted in any of the patients at last follow-up. Neuropsychological status was stable in this cohort before and after LITT. CONCLUSIONS sEEG can be safely used to localize seizures originating from insular and cingulate cortex. LITT can successfully treat seizures arising from these deep-seated structures. The insula and cingulum should be evaluated more frequently for seizure onset zones.

Automated summary

This study aimed to evaluate the success rate and complications of using sEEG and LITT for treating nonlesional refractory epilepsy in the cingulate and insular cortex. The results showed that both methods were safe and effective for treating this type of epilepsy.