Yuichi Hirose

The lateralized efficacy of vagus nerve stimulation (VNS) remains insufficiently explored. We report a case of drug-resistant epilepsy with bilateral frontal lobe seizure onset, treated with left cervical VNS. Preoperative video- electroencephalogram revealed predominant interictal discharges in the right hemisphere and frequent seizures from both hemispheres. Following VNS, overall seizure frequency decreased. Notably, stereo-electroencephalography performed 15 months postoperatively showed a marked reduction in right-sided seizures, while left-sided seizures remained frequent. This case highlights the potential lateralized effect of VNS in a single patient with bilateral frontal lobe epilepsy, suggesting that VNS may preferentially suppress seizures originating from the right hemisphere.

Compared to oligodendrogliomas, astrocytomas may have a relatively higher frequency of intracranial remote recurrence, despite generally favorable prognoses. Previous studies identified 8q gain, particularly in the terminal region, as a poor prognostic factor. This study evaluated MYC expression and its relationship with copy number gain at 8q24.21, in relation to recurrence patterns in astrocytomas, with a particular focus on intracranial remote recurrence. A retrospective analysis was conducted on 27 patients treated between 2006 and 2019. MYC expression was assessed by immunohistochemistry (IHC), and copy number status by metaphase comparative genomic hybridization and next-generation sequencing. Recurrence patterns were categorized as local or remote.Among 43 specimens analyzed by IHC, MYC expression was observed in 72%, with higher positivity in recurrent (80%) than initial (61%) specimens, though the difference was not statistically significant (p = 0.30). Copy number analysis showed a significant increase in 8q24.21 copy number in specimens from cases with remote recurrence compared to those with local recurrence (p = 0.033). However, no significant correlation was found between MYC copy number and protein expression (p = 0.055). These findings suggest that MYC is frequently expressed in astrocytomas, but its expression does not significantly reflect 8q gain or recurrence pattern.

BACKGROUND: This study aimed to determine the efficacy of flow diverters (FDs) for small/medium (≤10 mm) aneurysms and analyzed the factors that prevent aneurysm occlusion. METHODS: This retrospective single-center study evaluated the angiographic and clinical data of consecutive patients between June 2020 and February 2023. RESULTS: Overall, 121 small/medium aneurysms were observed in 106 patients treated with FDs. The median dome diameter was 6.1 (5.1-7.2) mm. Symptomatic thromboembolic complications were observed in four (3.7 %) patients, and none showed a major ischemic stroke. Intracranial hemorrhage was detected using postprocedural computed tomography in one (0.9 %) patient with asymptomatic subarachnoid hemorrhage. The rate of permanent neurological deficits was 1.8 %, and the mortality rate was 0 %. No delayed ischemic or hemorrhagic complications were observed during follow-up. Angiographic follow-up revealed complete and adequate occlusion (O'Kelly-Marotta grades C and D) rates of 77.5 % and 90.8 %, respectively. On multivariate analysis, incomplete occlusion was only associated with the presence of a branch vessel from the aneurysm dome (P < 0.01). In aneurysms with incorporated branch vessels, univariate analysis revealed that coil usage was a predictor of complete occlusion (P = 0.03). Moreover, even without using coils, effective occlusion was achieved when the branch vessel diameter was small (P = 0.03). CONCLUSIONS: FDs are an effective and safe treatment option for small/medium aneurysms. The presence of incorporated branch vessels can predict incomplete occlusion. Even in aneurysms with incorporated branch vessels, FD can obtain therapeutic effects by adding coil embolization or treating with only FD if the branch vessel diameter is small.

OBJECTIVE: Knowledge of the location of tumor-feeding arteries is necessary for the safe surgery of intracranial meningiomas. Hence, this retrospective study aimed to comprehensively analyze the distribution of tumor-feeding arteries. METHODS: Patients who underwent intracranial meningioma surgery at our institution between 2015 and 2023 were included in this study. The tumor attachment sites and tumor-feeding arteries were evaluated based on the results of preoperative examinations. The tumor attachment sites were classified as non-skull bases (convexity, parasagittal, and falx) or skull bases (anterior skull base, sphenoid ridge, sphenopetroclival, petrous, tentorial, cerebellar convexity, and foramen magnum). These tumors were further subdivided according to their attachment areas. RESULTS: Among the 180 patients included, the tumor-feeding arteries were identified in 177 patients (98.3%). In 67 patients with non-skull base meningiomas, the middle meningeal artery primarily functioned as a tumor-feeding artery in the anterior and middle regions (78 of 108 feeding arteries, 72.2%), while the extracranial artery served as a tumor-feeding artery in the posterior region (20 of 37 feeding arteries, 54.1%). Conversely, skull base meningiomas exhibited a higher frequency of having tumor-feeding arteries derived from the internal carotid artery (132 of 278 feeding arteries; 47.5%); these tumor-feeding arteries are often found at the deepest part of the surgical field during tumor resection and require careful intraoperative handling. CONCLUSIONS: Tumor-feeding arteries originate from different dural arteries depending on the tumor attachment site. These findings could help enhance surgical safety, especially in patients with meningiomas who have not undergone preoperative angiography.