Anatomical variations in the middle cerebral artery affect outcomes of mechanical thrombectomy in M1 occlusion cases. However, the relationship between middle cerebral artery branching patterns-specifically trifurcation and bifurcation-and mechanical thrombectomy outcomes remains unclear. This study investigated that relationship and attempted to identify optimal mechanical thrombectomy strategies for trifurcation patterns. We retrospectively analyzed patients treated with mechanical thrombectomy for M1 occlusion at our institution between 2019 and 2024. Patients were categorized into bifurcation and trifurcation groups based on middle cerebral artery branching patterns, and differences in outcomes between the groups were analyzed. In the trifurcation group, further analysis compared characteristics between patients with and without successful recanalization, defined as a modified Thrombolysis in Cerebral Infarction score of 2b-3. Among 98 patients (trifurcation, n = 21; bifurcation, n = 77), the trifurcation group showed lower successful recanalization rates (57% vs. 91%, p = 0.001) and higher procedural complication rates, including distal thrombus migration (62% vs. 36%, p = 0.047) and symptomatic intracerebral hemorrhage (38% vs. 14%, p = 0.027), compared with the bifurcation group. A multivariate modified Poisson regression demonstrated that the trifurcation pattern was independently associated with reduced successful recanalization (relative risk = 0.22; 95% confidence interval, 0.09-0.53; p = 0.001). In trifurcation cases, contact aspiration achieved higher successful recanalization rates than the combined technique (100% vs. 44%, p = 0.009). Moreover, in combined technique cases, direct contact between the aspiration catheter and thrombus significantly improved recanalization rates (77% vs. 0%, p < 0.001) without increasing complications. Trifurcation anatomy hindered effective clot engagement by the aspiration catheter because of narrow M2 diameters and large branching angles, resulting in lower successful recanalization rates compared with bifurcation.

This study investigated the hemodynamic effects of anastomosis site selection in superficial temporal artery to middle cerebral artery bypass surgery using computational fluid dynamics based on three-dimensional cerebral vascular models. By noninvasively reproducing blood flow changes that are difficult to evaluate in clinical settings, we visualized and quantified the effects of different bypass locations under both normal and stenotic conditions. To our knowledge, this is the first study to noninvasively evaluate the validity of anastomosis site selection in superficial temporal artery to middle cerebral artery bypass surgery using computational fluid dynamics simulation. The results demonstrated that factors, such as the distance from the anastomosis site to the target territory, flow direction, recipient vessel diameter, and pressure gradient, significantly influenced cerebral perfusion. In particular, bypass configurations that ensured antegrade flow, minimized the distance to the target region, and involved a larger recipient vessel diameter showed greater improvement in blood flow. These findings offer practical guidance for preoperative planning and are expected to contribute to the safer and more effective selection of bypass sites.

Although the efficacy of endovascular therapy for large-vessel occlusion is well-established, its effectiveness in the M2 segment of middle cerebral artery occlusion remains uncertain. This study aimed to identify which M2 segment of middle cerebral artery occlusion cases may benefit from endovascular therapy by focusing on the first-pass effect, which refers to patients who underwent endovascular therapy and achieved complete reperfusion after 1 pass. The study analyzed computed tomography perfusion imaging using the Rapid Processing of Perfusion and Diffusion software. In this retrospective study, we analyzed 71 patients with M2 segment of middle cerebral artery occlusion who underwent endovascular therapy after computed tomography perfusion imaging using the Rapid Processing of Perfusion and Diffusion software. The patients were divided into 2 groups: the first-pass effect group (n = 15) and the No first-pass effect group (n = 56). The first-pass effect group showed a significantly higher proportion of patients with a modified Rankin Scale score of 0-2 at 90 days than the No first-pass effect group (80.0% vs. 39.3%; adjusted odds ratio: 12.6, 95% confidence interval: 1.27-125.5). Among Rapid Processing of Perfusion and Diffusion-derived parameters, a median Hypoperfusion Intensity Ratio, an index of collateral status, was significantly lower in the first-pass effect group, with a suggested threshold of <0.22. In patients with M2 segment of middle cerebral artery occlusion, achieving first-pass effect was associated with better neurological outcomes. First-pass effect was more likely when Hypoperfusion Intensity Ratio was ≤ 0.22, suggesting this parameter may guide treatment decisions.

In Japan, which has become a super-aging society, the incidence of spontaneous intracerebral hemorrhage among older adults is increasing. Managing these patients is often complicated by frailty and systemic comorbidities. Although these issues pose unique challenges, there is limited research on spontaneous intracerebral hemorrhage in this population, leaving their clinical characteristics and prognoses unclear. This retrospective study reviewed spontaneous intracerebral hemorrhage patients aged ≥75 years who were admitted to our institution from April 2004 to March 2024. Demographics, clinical presentation, imaging findings, and in-hospital outcomes were analyzed to identify risk factors for both 30-day and complication-related mortality. A total of 501 patients were included in the study, with 213 (42.5%) categorized as the oldest-old (age ≥85 years). Over the 2-decade study period, the proportion of oldest-old spontaneous intracerebral hemorrhage patients increased, and this age group exhibited a high risk of complication-related mortality (16.9%). Multivariate analysis identified age ≥85 years (odds ratio: 4.25, 95% confidence interval: 2.12-8.51, p < 0.001), Glasgow Coma Scale score ≤8 at admission (odds ratio: 2.27, 95% confidence interval: 1.19-4.34, p = 0.013), and serum albumin ≤3.5 g/dL at admission (odds ratio: 2.12, 95% confidence interval: 1.07-4.19, p = 0.031) as independent risk factors for complication-related mortality. The prognosis of spontaneous intracerebral hemorrhage in older adults is significantly worse in individuals aged ≥85 years. Older patients with spontaneous intracerebral hemorrhage are at a heightened risk of complication-related mortality, which is primarily associated with advanced age, neurological severity, and hypoalbuminemia.

Subarachnoid hemorrhage is a life-threatening cerebrovascular event, and cerebral vasospasm remains a major cause of poor neurological outcomes. Clazosentan, an endothelin-A receptor antagonist, has been recently approved in Japan to reduce post-subarachnoid hemorrhage vasospasm; however, recurrent vasospasm after cessation of therapy has occasionally been reported, which underlying mechanisms remain unclear. Moreover, endothelin-A receptor is also expressed on pericytes; however, the effects of clazosentan on microvascular endothelin-A receptor remain unexplored. In this study, we employed a rat subarachnoid hemorrhage model to investigate the temporal dynamics of vasospasm and endothelin-A receptor expression in both large arteries and microvessels, and to evaluate the effects of clazosentan administration. Sprague-Dawley rats were assigned to naïve controls, subarachnoid hemorrhage with saline, or subarachnoid hemorrhage with continuous clazosentan administration for 7 days via osmotic pumps. Vasospasm was assessed by arterial wall thickness, and endothelin-A receptor expression was quantified using immunohistochemistry and immunofluorescence, including staining with α-SMA, CD31, and PDGF-β. Clazosentan significantly attenuated vasospasm in the middle and anterior cerebral arteries, and recurrent vasospasm was observed 3 days after cessation of clazosentan, coinciding with sustained upregulation of endothelin-A receptor in these vessels. In microvessels, pericyte density transiently decreased, peaking at a nadir on day 3 post-subarachnoid hemorrhage, while endothelin-A receptor expression on pericytes was highest at the same time point, and further elevated by clazosentan treatment. These findings indicate that clazosentan induces endothelin-A receptor upregulation in both macro- and microcirculation, potentially contributing to recurrent vasospasm after treatment, and highlight the critical role of pericytes in post-subarachnoid hemorrhage vascular regulation.

This study evaluated 14 patients who underwent robot-assisted deep brain stimulation electrode implantation and described our early experiences and workflows in both awake and asleep states. The deep brain stimulation targets included the subthalamic nucleus (n = 6), anterior thalamic nucleus (n = 5), and globus pallidus internus (n = 3). The patient was placed in the supine position, and the ROSA system was affixed diagonally onto the Leksell head frame to align with the X-ray system. Registration was performed at the center of each Leksell pin opening. In some patients with globus pallidus internus-deep brain stimulation, we performed semi-microelectrode recording to confirm the inferior border of the globus pallidus internus even under general anesthesia. In all patients with subthalamic nucleus-deep brain stimulation, semi-microelectrode recording was used to confirm the subthalamic nucleus location under local and intravenous anesthesia. In patients with anterior thalamic nucleus-deep brain stimulation, we used several methods for burr holes to avoid cerebrospinal fluid leakage as much as possible because of the trajectories running through the lateral ventricles. Deep brain electroencephalography was performed after the electrodes were inserted into the anterior thalamic nucleus. Deep brain stimulation implantation using the ROSA system was performed smoothly without any trouble in all patients. No intraoperative complications or major complications were reported immediately after deep brain stimulation. This study represents the first reported experience with ROSA-assisted deep brain stimulation in Japan and supports its broader application in awake or asleep state, and with or without semi-microelectrode recording.