Our understanding of the pathogenesis of intracranial aneurysms has been deepened through a series of studies. In this process, animal models of intracranial aneurysms have contributed greatly by providing experimental evidence with the causative relationship. Currently, intracranial aneurysms are considered a chronic inflammatory disease affecting the bifurcation site of intracranial arteries driven by non-physiological hemodynamic loading due to unique morphology of the lesions. On the basis of elucidated molecular mechanisms regulating intracranial aneurysm pathology, a clear possibility for the development of a novel therapy or a diagnostic tool to prevent or predict the formation, growth, or rupture of these lesions has been suggested.

The transradial approach using dedicated guiding catheters, such as the RIST guiding catheter, has gained popularity in neuroendovascular treatment. However, concerns remain regarding system instability. We evaluated the feasibility and safety of transradial approach with advancement of the RIST to a higher and more stable position (petrous to cavernous segment of the internal carotid artery). We conducted a single-center, retrospective, era-based cohort study comparing a transfemoral approach-first era (2022-2023) with a transradial approach with high RIST placement-first era (2024-2025). Consecutive adult patients who underwent endovascular treatment for unruptured intracranial aneurysms were included. After the exclusion of posterior circulation and ruptured aneurysms, 171 procedures (96 transfemoral approach and 75 transradial approach) were analyzed. The primary outcome was procedural success. Safety outcomes included neurological complications, access-site complications, and 30-day mortality. The primary analysis was era-based; sensitivity analyses were performed per protocol, and subgroup analyses focused on lesion laterality. In the transradial approach-first era, the procedural success rate was 99% (odds ratio 1.57, 95% confidence interval 0.14-17.70, p > 0.99), neurological complications occurred in 3%, access-site complications in 3%, and 30-day mortality in 0%, comparable to those in the transfemoral approach-first era. Sensitivity analyses restricted to cases with high RIST placement yielded similar results. The subgroup analysis did not reveal any interaction between outcomes and lesion laterality; The P-values for interaction were 0.294 for procedural success, 0.079 for periprocedural neurological complications, and 0.176 for access-site complications. Transradial approach using a high RIST placement appears feasible and safe, achieving high success and low complication rates.

Minimally invasive surgery for intracerebral hemorrhage is typically performed in the acute phase; however, in frail older adults, the risks of general anesthesia may outweigh the benefits of an early intervention. This study evaluated a "consistency-guided" strategy, in which hematoma evacuation is delayed until liquefaction allows endoscopic removal under local anesthesia. We retrospectively analyzed patients aged ≥70 years with lobar hemorrhages of ≥30 mL, excluding deep-seated types. Patients were categorized into 3 groups: subacute endoscopic surgery performed between days 7 and 14 based on hematoma consistency, acute craniotomy performed for neurological deterioration, and conservative management. The hematoma evacuation rate, operative metrics, complications, and functional outcomes were assessed using the modified Rankin Scale at 90 days and Functional Independence Measure gain. Among the 43 patients (endoscopic: 18, craniotomy: 11, conservative: 14), baseline hemorrhage severity was comparable across groups, with mean intracerebral hemorrhage scores of 3.07, 2.27, and 2.64, respectively. The endoscopic group achieved a high evacuation rate (median 88%) with significantly shorter operative times than the craniotomy group (50 vs. 180 min) and had no postoperative respiratory complications. Although the median 90-day modified Rankin Scale score was 5 across all groups, the endoscopic group demonstrated significantly greater Functional Independence Measure gain compared with conservative management, particularly among patients with hematoma volumes ≥40 mL. Delayed endoscopic evacuation under local anesthesia appears to be a feasible and safe strategy for older adults with frailty and may contribute to improved functional recovery in this population.

Degenerative lumbar canal stenosis is characterized by fibrosis-driven thickening of the ligamentum flavum, which is a key factor in the pathology of the disease and is responsible for clinical symptoms. Given the central role of transforming growth factor-β/Small mothers against decapentaplegic (Smad) signaling in fibrosis, this study aimed to investigate its role in ligamentum flavum remodeling in patients with degenerative lumbar canal stenosis. Ligamentum flavum tissue samples were obtained from 27 patients undergoing surgery for either degenerative lumbar canal stenosis (n = 18) or lumbar disc herniation (n = 9). The lumbar disc herniation patients served as the control group. The severity of the fibrosis was quantified using Masson trichrome and hematoxylin-eosin staining, and radiological measurement of ligamentum flavum thickness. Quantitative reverse transcription-polymerase chain reaction was used to analyze gene expression levels of transforming growth factor-β, transforming growth factor-β receptor, Smad2, Smad3, and Smad4. Changes at the protein level were verified using Western blot analysis. All statistical analyses were conducted post-normalization. Based on histological evaluation, the degenerative lumbar canal stenosis group showed a significantly higher degree of fibrosis compared to the control group. Radiological measurements also revealed increased ligamentum flavum thickness in the degenerative lumbar canal stenosis group (p < 0.0001). Significant upregulation (p < 0.05) of the Ski, transforming growth factor-β, transforming growth factor-β receptor, Smad2, Smad3, and Smad4 genes was detected, as confirmed by Western blot results. Collective analysis indicated that reduced SnoN gene expression in degenerative lumbar canal stenosis undermined the inhibition of target proteins on Smad2 and Smad3, resulting in elevated levels of phosphorylated Smad2/3. These findings suggest that downregulating SnoN may enhance the activation of the transforming growth factor-β/transforming growth factor-β receptor/Smad2/3 signaling pathway, thereby promoting ligamentum flavum fibrosis in patients with degenerative lumbar canal stenosis.

Tumor stiffness strongly influences exposure, extent of resection, operative time, and approach in meningioma surgery, but magnetic resonance imaging–based prediction still relies mainly on qualitative assessment. We evaluated whether a diffusion-derived stiffness surrogate calculated from diffusion-weighted magnetic resonance imaging–based virtual elastography correlates with intraoperative quantitative tumor stiffness in meningiomas and assessed its usefulness for preoperative stiffness prediction. Of 33 patients who underwent meningioma surgery between May 2022 and January 2025, 22 with both preoperative virtual elastography and intraoperative stiffness measurements were analyzed. Preoperative 3-Tesla diffusion-weighted magnetic resonance imaging with 2 b values was used to generate shifted apparent diffusion coefficient maps, and a single-slice volume of interest with a 5.51 mm slice thickness was manually delineated on the axial slice showing the largest tumor cross-sectional area. Intraoperative tumor stiffness of approximately 1-cm³ fresh specimens was measured with a rheometer and expressed as Young's modulus. The relationship between the diffusion-derived stiffness surrogate and stiffness was examined using Pearson correlation and multivariate linear regression. The diffusion-derived stiffness surrogate showed a significant negative correlation with tumor stiffness (r = −0.655, p = 0.00094), and this association remained significant after exclusion of embolized cases. Lower diffusion-derived stiffness surrogate values were associated with firmer tumors, whereas higher values were associated with softer tumors. These findings indicate that diffusion-weighted magnetic resonance imaging–based virtual elastography may provide a noninvasive, quantitative preoperative surrogate marker for estimating the stiffness of selected solid components of meningiomas and may offer adjunctive information for surgical planning.

Japan is undergoing rapid population aging, and glioblastoma is increasingly diagnosed in older adults. However, nationwide data on regional variation in age distribution, surgical volume, population-adjusted incidence, and treatment selection for newly diagnosed glioblastoma remain limited. Using anonymized data from the Japan Neurosurgical Database between 2018 and 2023, we analyzed patients with newly diagnosed glioblastoma who underwent initial tumor resection or biopsy and examined inter-prefectural heterogeneity in surgical practice patterns. Patient age was categorized into 5-year groups and stratified as <75 and ≥75 years, and prefecture-specific population data from the 2020 national census were used to calculate population-adjusted incidence.

Across all 47 prefectures, the age distribution of surgically treated patients differed significantly from that of the general population, with older patients being consistently overrepresented. The magnitude of this difference varied substantially among prefectures, indicating marked regional heterogeneity in the age profile of patients undergoing surgical management. Significant inter-prefectural differences were also observed in the surgical volume, the population-adjusted incidence, and the balance between resection and biopsy. Patients undergoing biopsy were older than those undergoing resection, although the magnitude of this difference varied regionally. The proportion of tumor resection ranged widely across regions and persisted even among patients aged ≥75 years. Importantly, baseline functional status (modified Rankin Scale) and admission consciousness level (Japan Coma Scale) were largely comparable across the prefectures.

These findings demonstrate substantial regional heterogeneity in the initial surgical management of glioblastoma in Japan that cannot be fully explained by population aging or patient condition alone.

Underlying atherosclerotic stenosis is more common in acute basilar artery occlusion than in anterior circulation, and often necessitates additional procedures such as balloon angioplasty or stent placement during endovascular revascularization. Preoperative recognition of underlying basilar artery stenosis may be clinically relevant, but reliable imaging indicators remain unclear. This study aimed to identify preoperative magnetic resonance imaging findings associated with underlying basilar artery stenosis in patients undergoing acute endovascular revascularization. We retrospectively analyzed patients at three institutions between 2018 and 2023. Patients were divided into stenosis and non-stenosis groups based on post-recanalization angiographic findings. Stenosis was identified in 13 patients and was found to be absent in 35 patients. Pontine hyperintensity on diffusion-weighted imaging was more frequent in the stenosis group and remained independently associated with preexisting basilar artery stenosis after adjustment for preoperative National Institutes of Health Stroke Scale score. Non-visualization of the proximal basilar artery on magnetic resonance angiography was also more frequent in the stenosis group, but did not remain independently associated after adjustment. Additional endovascular procedures were more frequently required in the stenosis group, whereas recanalization was achieved with mechanical thrombectomy alone in the non-stenosis group. Functional outcomes at discharge were comparable between the groups. In acute basilar artery occlusion, pontine hyperintensity on diffusion-weighted imaging was independently associated with preexisting basilar artery stenosis. Its absence may help exclude underlying stenosis, whereas concordant positivity of pontine hyperintensity and proximal basilar artery non-visualization may support suspicion of stenosis before treatment.