1Department of Neurosurgery, Osaka City University Graduate School of Medicine.
Departments of2Pediatric Neurosurgery and.
J Neurosurg Pediatr. 2021 Feb 26;27(5):572-580. doi: 10.3171/2020.9.PEDS20520. Print 2021 May 1.
Epileptic spasms (ESs) are classified as focal, generalized, or unknown onset ESs. The classification of ESs and surgery in patients without lesions apparent on MRI is challenging. Total corpus callosotomy (TCC) is a surgical option for diagnosis of the lateralization and possible treatment for ESs. This study investigated phase-amplitude coupling (PAC) of fast activity modulated by slow waves on scalp electroencephalography (EEG) to evaluate the strength of the modulation index (MI) before and after disconnection surgery in children with intractable nonlesional ESs. The authors hypothesize that a decreased MI due to surgery correlates with good seizure outcomes.
The authors studied 10 children with ESs without lesions on MRI who underwent disconnection surgeries. Scalp EEG was obtained before and after surgery. The authors collected 20 epochs of 3 minutes each during non-rapid eye movement sleep. The MI of the gamma (30-70 Hz) amplitude and delta (0.5-4 Hz) phase was obtained in each electrode. MIs for each electrode were averaged in 4 brain areas (left/right, anterior/posterior quadrants) and evaluated to determine the correlation with seizure outcomes.
The median age at first surgery was 2.3 years (range 10 months-9.1 years). Two patients with focal onset ESs underwent anterior quadrant disconnection (AQD). TCC alone was performed in 5 patients with generalized or unknown onset ESs. Two patients achieved seizure freedom. Three patients had residual generalized onset ESs. Disconnection surgeries in addition to TCC consisted of TCC + posterior quadrant disconnection (PQD) (1 patient); TCC + AQD + PQD (1 patient); and TCC + AQD + hemispherotomy (1 patient). Seven patients became seizure free with a mean follow-up period of 28 months (range 5-54 months). After TCC, MIs in 4 quadrants were significantly lower in the 2 seizure-free patients than in the 6 patients with residual ESs (p < 0.001). After all 15 disconnection surgeries in 10 patients, MIs in the 13 target quadrants for each disconnection surgery that resulted in freedom from seizures were significantly lower than in the 26 target quadrants in patients with residual ESs (p < 0.001).
In children with nonlesional ESs, PAC for scalp EEG before and after disconnection surgery may be a surrogate marker for control of ESs. The MI may indicate epileptogenic neuronal modulation of the interhemispheric corpus callosum and intrahemispheric subcortical network for ESs. TCC may be a therapeutic option to disconnect the interhemispheric modulation of epileptic networks.
癫痫痉挛（ES）分为局灶性、全面性和未知起病 ES。对于 MRI 上无病灶的 ES 患者，其 ES 的分类和手术治疗具有挑战性。全胼胝体切开术（TCC）是诊断侧化和可能治疗 ES 的一种手术选择。本研究通过头皮脑电图（EEG）上快波调制慢波的相位-幅度耦合（PAC），评估了 10 例无病灶性难治性 ES 患儿在 disconnective 手术后快波调制指数（MI）的变化。作者假设手术导致的 MI 降低与良好的癫痫发作结果相关。
作者研究了 10 例 MRI 无病灶的 ES 患儿，他们接受了 disconnective 手术。手术前后均行头皮 EEG 检查。作者采集了 20 个 3 分钟的非快速眼动睡眠期的脑电数据。在每个电极中获得伽马（30-70Hz）振幅和德尔塔（0.5-4Hz）相位的 MI。对 4 个脑区（左/右、前/后象限）的每个电极的 MI 进行平均，并评估与癫痫发作结果的相关性。
首次手术的中位年龄为 2.3 岁（范围 10 个月-9.1 岁）。2 例局灶性 ES 患者行前象限 disconnective（AQD）。5 例全面性或未知起病 ES 患者单独行 TCC。2 例患者达到无癫痫发作。3 例患者仍有全面性 ES。TCC 后行 TCC+后象限 disconnective（PQD）（1 例）、TCC+AQD+PQD（1 例）、TCC+AQD+半球切开术（1 例）。7 例患者在平均 28 个月（5-54 个月）的随访中无癫痫发作。在 2 例无癫痫发作的患者中，TCC 后 4 个象限的 MI 明显低于 6 例仍有 ES 的患者（p<0.001）。在 10 例患者的 15 次 disconnective 手术后，无癫痫发作的 13 个手术目标象限的 MI 明显低于仍有 ES 的 26 个手术目标象限（p<0.001）。
在非病灶性 ES 患儿中，disconnective 手术前后头皮 EEG 的 PAC 可能是 ES 控制的替代标志物。MI 可能提示癫痫起源于胼胝体的神经元调制和半球间的皮质下网络。TCC 可能是切断癫痫网络的侧化调制的治疗选择。
