Department of Neurosurgery, Affiliated Hospital of Southwest Medical University, Luzhou, China.
Department of Neurosurgery, The PLA Western Theater Command General Hospital, Chengdu, China.
J Neurol Surg A Cent Eur Neurosurg. 2024 May;85(3):294-301. doi: 10.1055/a-2202-9344. Epub 2023 Nov 2.
BACKGROUND: High-frequency oscillations (HFOs) are spontaneous electroencephalographic (EEG) events that occur within the frequency range of 80 to 500 Hz and consist of at least four distinct oscillations that stand out from the background activity. They can be further classified into "ripples" (80-250 Hz) and "fast ripples" (FR; 250-500 Hz) based on different frequency bands. Studies have indicated that HFOs may serve as important markers for identifying epileptogenic regions and networks in patients with refractory epilepsy. Furthermore, a higher extent of removal of brain regions generating HFOs could potentially lead to improved prognosis. However, the clinical application criteria for HFOs remain controversial, and the results from different research groups exhibit inconsistencies. Given this controversy, the aim of this study was to conduct a meta-analysis to explore the utility of HFOs in predicting postoperative seizure outcomes by examining the prognosis of refractory epilepsy patients with varying ratios of HFO removal. METHODS: Prospective and retrospective studies that analyzed HFOs and postoperative seizure outcomes in epilepsy patients who underwent resective surgery were included in the meta-analysis. The patients in these studies were grouped based on the ratio of HFOs removed, resulting in four groups: completely removed FR (C-FR), completely removed ripples (C-Ripples), mostly removed FR (P-FR), and partial ripples removal (P-Ripples). The prognosis of patients within each group was compared to investigate the correlation between the ratio of HFO removal and patient prognosis. RESULTS: A total of nine studies were included in the meta-analysis. The prognosis of patients in the C-FR group was significantly better than that of patients with incomplete FR removal (odds ratio [OR] = 6.62; 95% confidence interval [CI]: 3.10-14.15; < 0.00001). Similarly, patients in the C-Ripples group had a more favorable prognosis compared with those with incomplete ripples removal (OR = 4.45; 95% CI: 1.33-14.89; = 0.02). Patients in the P-FR group had better prognosis than those with a majority of FR remaining untouched (OR = 6.23; 95% CI: 2.04-19.06; = 0.001). In the P-Ripples group, the prognosis of patients with a majority of ripples removed was superior to that of patients with a majority of ripples remaining untouched (OR = 8.14; 95% CI: 2.62-25.33; = 0.0003). CONCLUSIONS: There is a positive correlation between the greater removal of brain regions generating HFOs and more favorable postoperative seizure outcomes. However, further investigations, particularly through clinical trials, are necessary to justify the clinical application of HFOs in guiding epilepsy surgery.
背景:高频振荡(HFOs)是自发的脑电图(EEG)事件,发生在 80 到 500 Hz 的频率范围内,由至少四个明显区别于背景活动的震荡组成。它们可以根据不同的频带进一步分为“棘波”(80-250 Hz)和“快棘波”(FR;250-500 Hz)。研究表明,HFOs 可能是识别难治性癫痫患者致痫区和网络的重要标志物。此外,更多地去除产生 HFOs 的脑区可能会带来更好的预后。然而,HFOs 的临床应用标准仍存在争议,不同研究组的结果也不一致。鉴于这种争议,本研究旨在通过检查不同 HFO 切除比例的难治性癫痫患者的术后癫痫发作结果,进行荟萃分析,探讨 HFOs 在预测术后癫痫发作结果中的效用。 方法:纳入了分析癫痫患者 HFOs 和术后癫痫发作结果的前瞻性和回顾性研究。这些研究中的患者根据 HFO 切除的比例进行分组,分为完全切除 FR(C-FR)、完全切除棘波(C-Ripples)、大部分切除 FR(P-FR)和部分棘波切除(P-Ripples)。比较每组患者的预后,以研究 HFO 切除比例与患者预后之间的相关性。 结果:共有 9 项研究纳入荟萃分析。C-FR 组患者的预后明显优于 FR 切除不完全的患者(比值比 [OR] = 6.62;95%置信区间 [CI]:3.10-14.15; < 0.00001)。同样,C-Ripples 组患者的预后也优于棘波切除不完全的患者(OR = 4.45;95%CI:1.33-14.89; = 0.02)。P-FR 组患者的预后优于 FR 大部分未切除的患者(OR = 6.23;95%CI:2.04-19.06; = 0.001)。在 P-Ripples 组中,大部分棘波切除的患者预后优于大部分棘波未切除的患者(OR = 8.14;95%CI:2.62-25.33; = 0.0003)。 结论:脑区产生 HFOs 的切除程度越大,术后癫痫发作的结果越好。然而,需要进一步的研究,特别是临床试验,来证明 HFOs 在指导癫痫手术中的临床应用。
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