Shape indices such as size ratio are valuable for diagnosing aneurysm rupture status and may influence rupture risk. However, as these indices are calculated based on two-dimensional measurements, bias may arise from observation directions. To address this, we developed a novel parameter, spatial projection ratio, utilizing three-dimensional geometry. A retrospective analysis of 225 aneurysms diagnosed using three-dimensional computed tomography angiography was conducted to evaluate primary variables and spatial projection ratio.

Spatial projection ratio is determined by defining the gravity point as the neck orifice center and identifying the furthest point from it using commercial software. The distance between these points, known as spatial projection length, is measured and divided by the equivalent neck diameter to calculate spatial projection ratio. Significant differences in morphological variables for rupture status were observed by Brunner-Munzel tests.

Receiver-operating characteristic curve analysis was employed to assess diagnostic accuracy, with Spearman's rank correlation utilized to explore the potential for predicting rupture risk by correlating spatial projection ratio and size ratio. Ruptured aneurysms exhibited significantly higher primary variables and shape indices compared to unruptured ones. The area under receiver-operating characteristic curves of all shape indices surpassed that of primary variables, with spatial projection ratio demonstrating a particularly high area under receiver-operating characteristic curves of 0.791 (95% confidence interval 0.732-0.849; sensitivity, 0.770; specificity, 0.741; cut-off value, 1.047). Moreover, spatial projection ratio exhibited a significant correlation with size ratio (r = 0.575, p < 0.01).

Thus, spatial projection ratio emerges as a robust morphological parameter for evaluating rupture status and may provide insights into aneurysm rupture risks.

Spinal ependymomas are common intramedullary tumors that can show dynamic changes in magnetic resonance imaging findings over time. This study aimed to analyze these imaging changes and their implications for perioperative management. The retrospective study included patients diagnosed with World Health Organization grade 2 spinal ependymoma who underwent surgical resection and had at least 2 preoperative magnetic resonance imaging scans. Patients were divided into 2 groups based on the presence or absence of radiographic changes on magnetic resonance imaging. Magnetic resonance imaging analyses included non-contrast T1- and T2-weighted images, as well as gadolinium-enhanced T1-weighted images when available. Key features evaluated included intraparenchymal edema, hemosiderin deposition, syringomyelia, and cyst components. Changes in tumor size and contrast enhancement patterns were documented. Radiographic changes were identified in 4 out of 15 cases (26.7%). All cases with imaging changes exhibited hemosiderin deposition or hemorrhage, significantly higher than in cases without changes (100% vs. 18.2%, p < 0.05). No significant differences were observed in the presence of cystic components, syringomyelia, or edema between the groups. In the group with radiographic changes, the timeframe for these changes in the images ranged from 3 days to several years. Spinal ependymomas can demonstrate dynamic magnetic resonance imaging changes during the preoperative period, including both growth and reduction in tumor size. The presence of hemosiderin deposition or hemorrhage might be associated with these imaging changes. Proper timing of magnetic resonance imaging is crucial for informing surgical planning and optimizing treatment strategies for patients with spinal ependymomas.

There is limited high-level evidence guiding the surgical treatment of hypertensive intracerebral hemorrhage, leaving the decision to the clinician's discretion. To understand treatment practices, a questionnaire survey was conducted among members of the Japanese Society on Surgery for Cerebral Stroke. This survey examined stroke care systems at various institutions, stroke numbers, and treatment details of patients with hypertensive intracerebral hemorrhage from January 2021 to December 2023. We examined data from 42 facilities, compared with 10 primary stroke centers cores and 32 non-primary stroke center cores. The total number of physicians involved in stroke care (primary stroke center cores vs. non-primary stroke center cores, median interquartile range; 18 [11-26] vs. 8 [4-14], p = 0.01), stroke specialists (8 [5-12] vs. 4 [2-7], p = 0.03), and supervising stroke surgeons (2 [1-2] vs. 1 [0-2], p = 0.008) was significantly higher in the primary stroke center cores group. Overall, 36,412 patients with stroke were hospitalized: 68% had cerebral infarction, 22% cerebral hemorrhage, 8% subarachnoid hemorrhage, and 2% other strokes. The locations of hypertensive intracerebral hemorrhage varied, with the putamen (31%), thalamus (25%), and lobe (24%) being predominantly affected. Non-invasive treatment was more prevalent in non-primary stroke center cores for most hypertensive intracerebral hemorrhage types, except for putaminal and brainstem hemorrhages. Surgical interventions were more common in primary stroke center cores, with craniotomies, neuroendoscopic surgeries, and ventricular drainage being preferred for cerebellar hemorrhage (28%), caudate nucleus hemorrhage (20%), and intraventricular hemorrhage (41%). This study highlights the treatment variability of hypertensive intracerebral hemorrhage between primary stroke center and non-primary stroke center cores.

Middle meningeal artery embolization has increasingly been used to treat chronic subdural hematoma. However, the current state of its application and outcomes in Japan remains unclear. We conducted a multicenter observational study involving facilities affiliated with the Japanese Society for Neuroendovascular Therapy to assess current practices and clarify the usefulness and safety of middle meningeal artery embolization for chronic subdural hematoma. A total of 466 patients from 40 facilities were included. The mean age of the patients was 78.0 ± 10.5 years, and bleeding risks, including antithrombotic therapy or bleeding predisposition, were present in 36.1% of patients. The most common timing for middle meningeal artery embolization was after the second burr hole surgery, accounting for 34.8% of cases. N-butyl-2-cyanoacrylate was used as the embolic material in 67% of cases. The complication rate was 5.2%, with complication-related morbidity at 0.9%. Hematomas were stable in 91.5% of cases at 30 days post-middle meningeal artery embolization. The symptomatic recurrence rate was 8.9%. Cases that underwent middle meningeal artery embolization after the second or subsequent burr hole surgeries were significantly associated with symptomatic recurrence. This study is the first nationwide survey investigating the real-world clinical practice of middle meningeal artery embolization for chronic subdural hematoma in Japan. While it included many elderly patients, recurrent cases, and those with bleeding risks, the safety and usefulness of middle meningeal artery embolization were deemed acceptable. However, symptomatic recurrence was common even in cases with middle meningeal artery embolization when performed after the second or subsequent burr hole surgeries. A further prospective study will be warranted to clarify treatment indications, optimal timing, and treatment techniques of middle meningeal artery embolization.

Despite the recognized usefulness of a portable table-top microscope in microsurgical training, its effectiveness is limited when training involves anatomical models and long surgical instruments. This limitation arises from the microscope's exclusive mobility to an up-and-down direction and the restricted working space beneath it. To address these challenges, we customized the table-top microscope by attaching its scope body and focusing rack to a Visual Electronics Standards Association (San Jose, CA, USA) monitor arm, originally designed for mounting computer monitors. A multipurpose metal plate, known as a "cheese plate" and designed for use with photography cameras, was customized to function as an adapter between the microscope and the monitor arm. The plate has Visual Electronics Standards Association-standard screw holes, which allowed the connection between the microscope focusing rack and the Visual Electronics Standards Association monitor arm. This assembly, referred to as a focusing rack-adapter plate complex, was then mounted on the Visual Electronics Standards Association monitor arm. To evaluate the modified microscope, its view was compared with that of a traditional microscope using concentric circles and gauze on the slope models. The modified microscope, mounted on the Visual Electronics Standards Association monitor arm, exhibited remarkable flexibility in its working area, height, and angles. The total cost of the modification was approximately $140. The advantages of the modified microscope over the traditional one, shown by a comparative study, were primarily attributed to the enhanced mobility of the modified microscope. With its simple modification process and affordable cost, this upgraded microscope has the potential to greatly benefit neurosurgeons who undergo microsurgical training.

Negative remodeling, characterized by a decrease in the outer diameter of the terminal (C1) segment of the internal carotid artery and the proximal (M1) segment of the middle cerebral artery, is a hallmark of moyamoya disease. However, the role of the disease-susceptibility gene RNF213 in negative remodeling in moyamoya disease remains unclear. This study investigated the effect of RNF213 p.R4810K polymorphism on the degree of negative remodeling in moyamoya disease. We analyzed 70 hemispheres of 38 adult patients with moyamoya disease who underwent RNF213 p.R4810K gene analysis. Vascular outer diameters of the distal C1 and proximal M1 segments were measured using constructive interference in steady-state images obtained from 3-tesla magnetic resonance imaging. Suzuki stages were determined via cerebral angiography, and comparisons were made between RNF213-mutant and wild-type hemispheres. Among the analyzed hemispheres, 39 (56%) were RNF213-mutant, and 31 were wild-type. Suzuki stages were distributed as follows: 0 in 8 hemispheres, 1-2 in 15, 3-4 in 40, and 5-6 in 7. At stage 3-4, the C1 outer diameter was significantly smaller in RNF213-mutant hemispheres compared to wild-type (median 2.1 vs 2.6 mm, p < 0.05). A significant reduction in vascular outer diameters in the advanced disease stage was observed only in the mutant group between stages 0 and 3-4 (C1: median 3.0 vs 2.1 mm, p < 0.05; M1: median 2.2 vs 1.5 mm, p < 0.001). These findings suggest the association between RNF213 p.R4810K polymorphism and the progression of negative remodeling at the carotid fork in advanced disease stages of moyamoya disease.

Chronic subdural hematoma is a common disease in the field of neurosurgery, and the number of cases is expected to continue increasing in an aging society. At our hospital, minimally invasive percutaneous subdural perforation (the Aoki method) is the first-line treatment. We investigated the recurrence rate associated with the Aoki method, factors related to recurrence, and the complication risks. Among the cases treated with the Aoki method between June 2007 and December 2020, 383 (431 lesions) for which image analysis and recurrence tracking were possible were included. On the basis of the preoperative patient background (sex, age, history of taking antiplatelet and anticoagulant drugs, preoperative neurological findings, imaging findings (preoperative hematoma volume and hematoma density), surgical details, and postoperative use of concomitant drugs), we retrospectively analyzed the recurrence rate, factors related to recurrence, and complication risk. The recurrence rate was 23.7%, which is within the same range as that of burr-hole hematoma irrigation. Multivariate analysis showed that age and a large preoperative hematoma volume were associated with recurrence. One of the 3 cases with postoperative epidural and 2 of the 3 cases with subdural hematomas required craniotomy. The incidence of complications requiring additional surgery was approximately 1%, which is comparable to that of burr-hole irrigation. The Aoki method is efficient because it is minimally invasive and has a therapeutic effect equivalent to that of burr-hole irrigation, which is the current standard of care.

In adult isthmic spondylolysis/spondylolisthesis, a fibrocartilaginous mass, ragged edge, and decrease in disk height cause radiculopathy with intervertebral foraminal stenosis. There are few reports on the outcomes of full-endoscopic spine surgery for isthmic spondylolisthesis because of difficulty in the ragged edge resection. This study evaluated the short-term outcomes of our original full-endoscopic spine surgery technique in patients with isthmic spondylolisthesis with a focus on the "pars crisscross." An important landmark, the pars crisscross consist of the superior articular process at S1, floating lamina, inferior articular process at L4, and pars ragged edge. The exiting nerve root can only be decompressed by complete resection of the ragged edge after confirmation of the pars crisscross. This case series includes 6 patients (mean age 63.2 ± 14.3 years) who underwent full-endoscopic spine surgery under local anesthesia for radiculopathy. The leg pain improved immediately after surgery in all patients and the mean visual analog scale score improved from 8.2 ± 1.3 preoperatively to 1.2 ± 1.1 at 2 weeks postoperatively. The neuroforaminal area at the inlet and center expanded dramatically from 184 ± 41 mm² and 192 ± 45 mm², respectively, before surgery to 340 ± 55 mm² and 338 ± 80 mm² postoperatively. No patient experienced a recurrence of leg pain, aggravation of low back pain, or spinal instability during the 3 months after surgery. full-endoscopic spine surgery pars crisscross decompression had excellent short-term clinical and radiographic outcomes. Patients who are unsuitable for general anesthesia and instrumentation surgery could be candidates for this procedure.

Early brain injury after a subarachnoid hemorrhage is an important prognostic factor. Aging is also an important prognostic factor of subarachnoid hemorrhage. However, the association between early brain injury and aging remains unclear. Older patients have comorbidities and frailty that can affect early brain injury severity. The purpose of this retrospective study was to clarify the differences in early brain injury severity between young and older patients by adjusting for comorbidities and frailty using propensity score matching. Between 2013 and 2021, 433 patients with subarachnoid hemorrhage who presented within 72 hrs of onset were included. The patients were divided into 2 groups: those aged 18-65 years (young group) and those aged ≥75 years (older group). The primary end point was early brain injury, which comprised the clinical, radiological, and laboratory findings on admission. We used propensity score matching to adjust for histories, comorbidities, and frailty. We analyzed early brain injury in the 2 groups for both non-propensity score matching and propensity score matching cohorts. Within the non-propensity score matching cohort, 260 patients were included in the young group and 173 in the older group. The propensity score matching cohort comprised 98 patients from both groups. The older group showed a higher World Federation of Neurosurgical Societies grade (p < 0.001), higher Hijdra scale (p < 0.01), and higher proportion of acute hydrocephalus (p < 0.001) in both cohorts. The study indicated exacerbated early brain injury among older patients, with worsening neurological damage, increasing subarachnoid hemorrhage volume, and causing hydrocephalus. Clarifying the impact of aging on early brain injury may help develop therapeutic interventions for subarachnoid hemorrhage.