Prognostic value of electrocorticography findings during callosotomy in children with Lennox–Gastaut syndrome

Abstract

Based on our experience, changes in ECoG during callosotomy do not predict postoperative seizure outcome. Insignificant blockage of bisynchronous epileptiform discharges in ECoGs during callosotomy does not predict a worse prognosis than that associated with significant intraoperative blockage.

Post-section recruitment of epileptiform discharges in electrocorticography during callosotomy in 48 patients with Lennox–Gastaut syndrome

“…However, in our previous study of ECoG change during callosotomy for LGS, we found that greater blockage of bisynchronous ED per ECoG did not predict better postoperative prognosis. 3 Callosotomy did not necessarily abolish bisynchronous ED, which suggests contributions from more than a transfer mechanism. In addition, callosotomy frequently caused a reduction in seizure frequency and severity rather than the transformation of a generalized seizure to a lateralized or partial one.…”

“…Although a better clinical outcome was observed among patients in whom the bilateral synchrony of ED was disrupted by callosal section, they questioned the validity of this result because of possible biased findings in their small series. Kwan et al 3 found that greater blockage of bisynchronous ED per ECoG did not predict better postoperative prognosis in their 48 patient series. In a preliminary study, Binnie et al 2 found that ECoG spike rates following multiple subpial transections varied from complete abolition to a 200% increase, without a demonstrable relationship to either seizure outcome or completeness of transection.…”

“…PRED was defined as ED in the post-section ECoG that were more than twice (200%) the level in the pre-section ECoG (Figs. [2][3][4][5], as defined by Binnie et al 2 Patients whose post-section ECoG showed recruitment were further marked ''+ a'' (for example, Group 1A+ a); patients without recruitment were marked as ''À a'' (for example, Group 1AÀ a).…”

The role of the interictal EEG in selecting candidates for resective epilepsy surgery

“…Some series found that a "lateralized" pattern on the EEG predicted a better outcome or fewer discharges after surgery; however, this finding did not reach significance [69,[71][72][73][74][75][76]. EEG as an independent variable lacks significance in general, and suggests that the interictal EEG is not predictive of outcome [69,[77][78][79][80][81]. However, they are flawed either by retrospective design or by having too few and/or too heterogenous cases.…”

Utility of neuronavigation and neuromonitoring in epilepsy surgery

“…Changes in ECoG activity have also been used during corpus callosotomies as a means of determining the extent of surgery required and of predicting the postoperative seizure outcome; however, conflicting reports cast doubt upon its ability to influence these factors, and thus its use is not uniformly accepted. 16,44,99 In summary, the unparalleled precision afforded by ECoG can in many cases permit effective and relatively safe surgical management of nonlesional epilepsy that is intimately related to eloquent brain regions.…”