Tailored disconnection based on presurgical evidence in catastrophic epilepsy: report of 2 cases

Total and partial posterior quadrant disconnection for medically refractory epilepsy: A systematic review

PURPOSE

Posterior quadrant disconnection (PQD) is a surgical procedure for medically refractory epilepsy (MRE) involving diffuse regions of the temporo-parieto-occipital lobes. We sought to compare factors and efficacy according to PQD extent.

METHODS

We performed a systematic review of the literature reporting the use of PQD since 2004. We analyzed various characteristics of pooled cases, including the role of preoperative studies in patient selection, intraoperative techniques, and outcomes.

RESULTS

Our review of 137 patients from nine studies revealed 66% undergoing total PQD and 34% undergoing partial PQD. Interictal electroencephalography (EEG) findings were predominantly characterized as lateralized for total PQD (56%) and localized within the ipsilateral posterior quadrant in patients undergoing partial PQD (53%). Metabolic functional studies [positron emission tomography (PET) or ictal single-photon emission computed tomography (SPECT)] played a role in surgical decision-making in 42% of patients who underwent total PQD. Wada and/or functional magnetic resonance imaging (fMRI) was more often utilized for partial PQD (22%) than total PQD (3%) as was intracranial electroencephalography (icEEG) (30% versus 13%, respectively). Overall, 75% of total PQD patients achieved seizure freedom [defined as Engel I or International League Against Epilepsy (ILAE) Class 1 outcome] in comparison to 63% of partial PQD patients (p = .078). New visual field deficits were seen in 12% and new or worsened hemiparesis in 6%. For patients in either cohort, concordance of interictal and ictal EEG findings was found to be predictive of seizure freedom (p = .048).

CONCLUSION

Both total and partial PQD represent effective alternatives for managing patients with MRE whose seizure onset zone (SOZ) involves a diffuse region within the posterior quadrant. While PET and/or SPECT frequently aided in the decision to proceed with total PQD, patients who underwent a tailored, partial multilobar resection were more likely to undergo Wada and/or fMRI testing as well as stage I icEEG studies.

Noninvasive Presurgical Data for One-Stage Leucotomy in Catastrophic Epilepsy

BACKGROUND

Catastrophic epilepsy results in severe neurodevelopmental delay in infants because of frequent and/or long seizures. Therefore, consideration of early epilepsy surgery is essential for neurodevelopmental outcome. Once an infant with catastrophic seizures is identified as a surgical candidate, it is important that the surgical plan be carefully defined based on detailed presurgical evidence to minimize surgical complications in this age group.

CASE DESCRIPTION

We present 2 infants with catastrophic epilepsy, epileptic spasms, and bihemispheric electroencephalographic abnormalities who underwent one-stage disconnection surgery based on a sound hypothesis of the epileptogenic zone. Each patient underwent an extensive noninvasive presurgical investigation followed by stereotactic disconnection leucotomy in a single stage. After the 2 children were followed for 24-36 months. A seizure reduction by at least 90% (Engel class I) was achieved in both cases with subsequent improvement in neurodevelopmental progress. There were no perioperative complications. Both patients had widespread cortical dysplasia on pathologic evaluation.

CONCLUSIONS

Careful consideration of the noninvasive presurgical workup can identify focal onset even in the presence of catastrophic epilepsy with widespread bilateral abnormalities. Single-stage lobar leucotomy for disconnection of the epileptogenic zone can lead to excellent outcome in these patients.