Approximately 30% of patients still develop drug-resistant epilepsy despite the introduction of newer antiseizure medications. Brivaracetam, a high-affinity synaptic vesicle protein 2A ligand with a mechanism of action similar to that of levetiracetam, was only recently approved in Japan in June 2024 and became available at our institution in September 2024. Clinical data in real-world settings remain limited. To date, no real-world clinical data have been systematically reported in patients in Japan, and the present study aimed to characterize the initial real-world experience with Brivaracetam use shortly after its approval. We retrospectively analyzed 73 patients with focal epilepsy who initiated Brivaracetam at our center between September 2024 and August 2025, evaluating patient characteristics, seizure outcomes, treatment retention, and adverse events. Among 41 patients with at least 3 months of follow-up, seizure freedom was achieved in 5%, whereas 44% of patients were responders with ≥50% seizure reduction. Overall, 59 patients continued Brivaracetam, with a treatment retention rate of 76.5% and a mean treatment duration of 7.4 months. Adverse events were observed in 18 patients (24%), most frequently somnolence, followed by dizziness and irritability. Brivaracetam discontinuation occurred in 14 patients (19%), with psychiatric symptoms leading to discontinuation in only 3 patients (4%), a lower rate compared with prior reports of levetiracetam. These findings suggest that Brivaracetam is effective and generally well tolerated in patients in Japan with focal epilepsy. Future multicenter prospective studies with longer follow-up are warranted to further evaluate the role of Brivaracetam, including as monotherapy and in patients with multilobar epilepsy.

The asymmetry of the A1 segment of the anterior cerebral artery has been implicated in the development and rupture of anterior communicating artery aneurysms; however, its relationship with the severity of subarachnoid hemorrhage remains unclear. We retrospectively analyzed 114 patients with subarachnoid hemorrhage due to ruptured anterior communicating artery aneurysms (mean age, 64.2 ± 13.9 years; 56 males, 58 females) treated at 2 institutions between January 2014 and March 2024. Patients were categorized into Symmetric and Asymmetric A1 groups, with asymmetry defined as a diameter ratio of ≥2 between sides. Among the 114 patients, 72 (63.2%) and 42 (36.8%) had symmetric and asymmetric A1 segments, respectively. The Asymmetric A1 group demonstrated significantly larger aneurysm size, a higher incidence of World Federation of Neurosurgical Surgeons grade IV-V, and more frequent intracerebral hemorrhage. Surgical clipping was more frequently performed in the Asymmetric A1 group (p = 0.04), likely due to associated intracerebral hemorrhage. The A1 diameter ratio was negatively correlated with aneurysm angle (r = −0.27, p < 0.01) and positively correlated with aneurysm length (r = 0.28, p < 0.01). Multivariate analysis showed an association of A1 asymmetry with severe clinical presentation but not with functional outcome. The effect of A1 asymmetry on severity was attenuated after adjustment for intracerebral hemorrhage, the strongest predictor of both severity and outcome. These findings suggest that in ruptured anterior communicating artery aneurysms, A1 asymmetry is associated with larger aneurysms, more severe subarachnoid hemorrhage, and higher rates of intracerebral hemorrhage.

Aneurysmal subarachnoid hemorrhage remains a devastating condition with persistently high rates of early mortality and disability. While numerous prognostic models exist, the prognostic relevance of metabolic dysfunction in aneurysmal subarachnoid hemorrhage remains uncertain. We retrospectively analyzed 60 consecutive patients with subarachnoid hemorrhage admitted between 2022 and 2024. Metabolic syndrome and its components-including impaired glucose tolerance, insulin resistance, hypertension, dyslipidemia, and obesity-were evaluated within 24 hours of admission. The primary endpoint was poor functional outcome at discharge (modified Rankin Scale 3-6). Secondary endpoints included in-hospital complications and mortality. In adjusted ridge-penalized logistic regression analyses, impaired glucose tolerance (adjusted odds ratio 4.93, 95% confidence interval 1.39-17.4, p = 0.014) and World Federation of Neurological Surgeons grade ≥3 (adjusted odds ratio 5.12, 95% confidence interval 1.62-16.18, p = 0.006) independently predicted poor outcome. Insulin resistance was independently associated with in-hospital complications (adjusted odds ratio 4.05, 95% confidence interval 1.15-14.3, p = 0.030). Mortality was independently predicted by age (adjusted odds ratio 1.06, 95% confidence interval 1.01-1.12, p = 0.032), World Federation of Neurological Surgeons grade ≥3, and impaired glucose tolerance. The composite metabolic syndrome variable was not an independent predictor of any outcome. In conclusion, specific metabolic abnormalities- impaired glucose tolerance, insulin resistance, and hypertension-rather than metabolic syndrome appear to drive early prognosis after subarachnoid hemorrhage. Early metabolic profiling and individualized glucose control may help identify patients at risk and guide future interventional studies.

This retrospective cohort study evaluated long-term local recurrence rates following microsurgical clipping of anterior circulation unruptured intracranial aneurysms. Between April 2003 and August 2025, 657 patients underwent 700 procedures for 786 aneurysms. Local recurrence was assessed by computed tomography angiography at 5-year intervals. During a mean follow-up of 10.5 ± 3.5 years (6,927.8 patient-years), 9 local recurrences were identified, yielding annual recurrence rates of 0.156% per patient-year and 0.111% per aneurysm-year. Cumulative recurrence-free rates were 100% at 5 years, 99.1% at 10 years, and 98.6% at 15 years. Location-specific analysis revealed significantly higher recurrence rates for internal carotid-anterior choroidal artery aneurysms (0.630% annually) and internal carotid-posterior communicating artery aneurysms (0.262% annually) compared with other locations (p = 0.011). Review of recurrent cases identified 3 mechanistic patterns: closure-line regrowth after parallel clipping (Pattern A, n = 2), residual thin-walled basal footprint in broad-based aneurysms (Pattern B, n = 2), and sub-angiographic remnants preserved for perforator safety (Pattern C, n = 5). The predominance of Pattern C at anterior choroidal artery and posterior communicating artery locations explains the location-specific recurrence risk. All recurrences occurred in aneurysms with complete obliteration (Sindou Grade 0) on early postoperative imaging, whereas no recurrences were observed among 26 cases (3.3%) with small neck remnants (Sindou Grades I-II). Microsurgical clipping of unruptured intracranial aneurysms demonstrated excellent long-term durability with very low local recurrence rates, though the gradual increase beyond 10 years highlights the need for continued surveillance, particularly at locations requiring perforator-preserving techniques.

Endovascular treatment is widely used for intracranial aneurysms, but evidence comparing endovascular treatment with surgical treatment for posterior communicating artery aneurysms is limited. Using a multicenter registry from January 2013 to December 2022, 841 patients with 851 posterior communicating artery aneurysms were analyzed. Logistic regression with multivariable adjustment and inverse probability of treatment weighting was applied to adjust for confounders. Of the aneurysms, 499 (58.6%) were treated by endovascular treatment. Patients undergoing endovascular treatment were generally older, had more comorbidities, and had larger aneurysms than those receiving surgical treatment. Functional outcomes assessed by the modified Rankin Scale showed no significant difference between endovascular treatment and surgical treatment in ruptured aneurysms (poor outcome at discharge: odds ratio, 1.09 [0.74-1.69]; p = 0.698; at final follow-up: odds ratio, 0.74 [0.48-1.15]; p = 0.183), whereas endovascular treatment was associated with significantly better outcomes in unruptured aneurysms (poor outcome at discharge: odds ratio, 0.11 [0.03-0.32]; p < 0.001; at final follow-up: odds ratio, 0.33 [0.11-0.96]; p = 0.045). Intraoperative and postoperative complications were similar overall (interoperative: odds ratio, 0.92 [0.55-1.54]; p = 0.752; postoperative: odds ratio, 0.76 [0.54-1.07]; p = 0.121). Subgroup analyses demonstrated that endovascular treatment reduced intraoperative complications in elderly patients, with a significant interaction between endovascular treatment and elderly age (p = 0.008). Endovascular treatment was associated with markedly higher recurrence (odds ratio, 37.41 [16.63-107.15]; p < 0.001) and retreatment rates (odds ratio, 13.73 [6.32-36.06]; p < 0.001). These findings suggest surgical treatment remains a viable option for ruptured aneurysms, providing similar functional outcomes with lower recurrence and retreatment rates, whereas endovascular treatment is suitable for unruptured aneurysms, offering comparable safety and potential advantages in elderly patients.

Tarsal tunnel syndrome is an entrapment neuropathy caused by the compression of the tibial nerve and its terminal branches in the tarsal tunnel. Electrophysiological examinations are often used to diagnose tarsal tunnel syndrome. Surgical decompression of the tibial nerve is performed in patients who are resistant to conservative treatment. However, the preoperative electrophysiological findings that predict surgical outcomes remain unknown. This study aimed to clarify the preoperative electrophysiological findings that predict the surgical outcomes of tarsal tunnel syndrome. We reviewed 28 feet of 23 patients who underwent preoperative electrophysiological examinations between November 2021 and October 2024, were diagnosed with tarsal tunnel syndrome, and subsequently underwent surgery. Electrophysiological examinations included nerve conduction study and needle electromyography. We reviewed patient characteristics and electrophysiological findings prior to surgery. Sensory plantar symptoms, such as numbness and pain, were evaluated using the Numerical Rating Scale before and after surgery. Patients were divided into the improvement and non-improvement groups based on the Numerical Rating Scale improvement rate after surgery. A comparative analysis of patient characteristics and preoperative electrophysiological findings was performed between the improvement and non-improvement groups. In a motor nerve conduction study of the tibial nerve, the amplitude of the compound motor action potential evoked by stimulation at the ankle was significantly lower in the non-improvement group than in the improvement group. In tarsal tunnel syndrome, a low compound motor action potential amplitude of the tibial nerve on preoperative motor nerve conduction study may indicate poor symptomatic improvement after surgery. Electrophysiological examinations may be useful for predicting the surgical outcomes of tarsal tunnel syndrome.

Oligodendrogliomas generally have a better prognosis than other adult-type diffuse gliomas. However, although several clinical and radiological prognostic factors have been reported, long-term outcomes remain heterogeneous, and decisions regarding postoperative treatment remain challenging because of concerns about long-term adverse effects. This study aimed to explore prognostic factors by analyzing clinical, radiological, therapeutic, and genetic data from a single-institution cohort.

We retrospectively reviewed adult patients (≥18 years) with isocitrate dehydrogenase-mutant and 1p/19q-codeleted oligodendrogliomas who underwent surgical resection at our institution between 1999 and 2021, with available preoperative magnetic resonance imaging and computed tomography. CDKN2A/B copy number status was assessed using multiplex ligation-dependent probe amplification and confirmed by fluorescence in situ hybridization. Overall survival and progression-free survival were analyzed using the Kaplan-Meier method and Cox proportional hazards models. For overall survival, simple multivariable Cox models adjusted for age and Karnofsky Performance Status were constructed.

A total of 32 patients were included. The median age was 40 years, and the median Karnofsky Performance Status was 90. Calcification and corpus callosum invasion were observed in 46.9% and 40.6% of cases, respectively, and CDKN2A/B hemizygous deletion was identified in four cases. The 5-year progression-free survival was 62.0%, and the 5-year overall survival was 86.5%. On univariable Cox analysis for overall survival, corpus callosum invasion, calcification, and CDKN2A/B hemizygous deletion were significant adverse prognostic factors. In simple multivariable Cox models, CDKN2A/B hemizygous deletion remained associated with shorter overall survival.

Calcification, corpus callosum invasion, and CDKN2A/B hemizygous deletion may be prognostic markers in oligodendroglioma.

Cystic vestibular schwannomas often grow more rapidly and adhere more strongly to the facial nerves and brainstem than do solid tumors. Patients with large cystic tumors may experience sudden clinical deterioration during the preoperative waiting period; furthermore, it is important to carefully consider whether to dissect the cyst wall from adjacent structures. Accordingly, we aimed to clarify the influence of different cyst types on surgical strategies. We included 19 patients with large cystic vestibular schwannomas (extrameatal diameter >30 mm) who underwent microsurgical resection. Tumors were classified using the Piccirillo et al. system based on the cyst location and wall thickness. We compared the incidence of sudden clinical deterioration and surgical outcomes according to the cyst types. Peripherally located thin-walled cysts (type B) were significantly more likely to cause sudden clinical deterioration than were centrally located thick-walled cysts (type A). In addition, when the thin cyst wall was firmly adhered to the facial nerve or brainstem, a conservative surgical strategy was applied, with the wall being intentionally left in place rather than attempting forceful dissection. This approach achieved excellent facial nerve preservation but relatively decreased the extent of resection. Taken together, these findings suggest that large cystic vestibular schwannomas with peripherally located thin-walled cysts have a high risk of rapid clinical deterioration and may require early surgical intervention. It is important to adapt the dissection strategy according to cyst wall thickness to achieve optimal postoperative preservation of the facial nerve.

Intraoperative transcranial motor-evoked potential recordings commonly utilize the belly tendon montage method; however, its reliability in large lower limb muscles such as the quadriceps femoris and hamstring muscles can be limited. We hypothesized that placing the reference electrode on the fibular head (fibular head reference electrode method) would improve waveform clarity and stability compared to belly tendon montage. This retrospective study analyzed 101 patients who underwent transcranial motor-evoked potential monitoring during spinal surgery at Nagoya University Hospital from October 2021 to August 2023. We compared compound muscle action potential amplitude, baseline waveform derivation success rate, noise amplitude, signal-to-noise ratio, and mean consecutive ratio between belly tendon montage and fibular head reference electrode method. Fibular head reference electrode method showed significantly higher median compound muscle action potential amplitudes in quadricep femoris (202.5 μV vs. 52.5 μV) and hamstring muscles (131.0 μV vs. 33.3 μV) with p < 0.001. Baseline waveform derivation success rates also improved with fibular head reference electrode method (quadricep femoris: 76.5% vs. 50.5%; hamstring muscles: 73.5% vs. 39.8%; p < 0.001). When noise amplitude increased, the signal-to-noise ratio improved significantly (p < 0.001), and mean consecutive ratio indicated better waveform stability in hamstring muscles. For predicting postoperative paralysis, fibular head reference electrode method yielded a sensitivity of 100% and a negative predictive value of 100% in both quadricep femoris and hamstring muscles, with specificities of 93.5% and 95.6%, respectively. These findings suggest that fibular head reference electrode method improves the reliability, clarity, and predictive value of transcranial motor-evoked potential monitoring in spinal surgery and may represent a superior alternative to conventional belly tendon montage.

Stereo-electroencephalography has recently gained attention as a less invasive and effective technique for presurgical evaluation in patients with drug-resistant epilepsy. Several studies have reported favorable outcomes when compared to conventional subdural electrode implantation. This study aimed to compare the target regions, complications, additional surgeries, and surgical outcomes between stereo-electroencephalography and subdural electrode implantation. A retrospective review was conducted on 83 consecutive patients who underwent intracranial electrode implantation between 2018 and 2024. Clinical variables were compared between the subdural electrode implantation (n = 41) and stereo-electroencephalography (n = 42) groups. In the stereo-electroencephalography group, 28 cases (66.7%) were implanted in the insular gyrus as the deep area, which was significantly different from the subdural electrode implantation group (8 cases, 19.5%). Resective surgery was performed in 39 subdural electrode implantation cases. In the stereo-electroencephalography group, 20 patients underwent resection, 14 received thermocoagulation, 5 were scheduled for surgery, and 3 were not eligible for surgery because the epileptogenic zone could not be identified. Intracranial hemorrhage occurred in 3 cases in each group. Two subdural electrode implantation cases were symptomatic and required reoperation, whereas all stereo-electroencephalography-related hemorrhages were asymptomatic. One year after surgery, seizure freedom was achieved in 57.9% (22 of 38 cases) of subdural electrode implantation and 64.0% (16 of 22 cases) of stereo-electroencephalography patients (p = 0.606). Seizure outcomes and complication rates were similar between stereo-electroencephalography and subdural electrode implantation, with fewer serious complications in the stereo-electroencephalography group. Stereo-electroencephalography was more frequently used in cases involving deep lesions or prior subdural implantation, highlighting its utility in technically challenging cases.

Chronic subdural hematoma remains one of the most common neurosurgical conditions in elderly patients, with anticoagulant use recognized as a major risk factor. This retrospective observational study investigated whether warfarin influences the temporal relationship between minor head trauma and the onset of neurological symptoms, here defined as the post-traumatic interval. Among 373 surgically treated patients between 2016 and 2022, only 126 with reliable trauma histories were included to minimize recall bias. Patients were stratified according to antithrombotic use (warfarin, aspirin, warfarin plus aspirin, or none). The median the post-traumatic interval was significantly shorter in the warfarin group compared with controls and aspirin users, suggesting that anticoagulation accelerates clinical manifestation. Warfarin was also associated with higher rates of bilateral hematomas, cerebral herniation, and poorer short-term functional outcomes, although most patients improved after surgical evacuation. The strict inclusion process reduced the sample size but increased the validity of the post-traumatic interval assessment, and the concept of the post-traumatic interval itself is not yet a validated clinical parameter. These findings raise the hypothesis that warfarin may shorten the latent period of chronic subdural hematoma through mechanisms of rebleeding and accelerated hematoma remodeling. Recognition of this effect could help clinicians anticipate earlier neurological deterioration in anticoagulated patients, underscoring the importance of early vigilance and imaging after seemingly trivial trauma in this high-risk population.

Intracerebral hemorrhage is frequently complicated by hematoma expansion, which is a major determinant of poor outcomes. Leakage sign, defined as progressive contrast extravasation on delayed computed tomography after angiography, has been proposed as a predictor of hematoma expansion. However, the relationship between onset-to-imaging time, hemorrhage location, and leakage sign positivity remains unclear. Data from 144 patients with primary supratentorial intracerebral hemorrhage were retrospectively collected and divided into 2 groups: leakage sign-positive (n = 58) and leakage sign-negative (n = 86) groups. Clinical characteristics, radiological findings, and outcomes were compared, and correlations between hematoma size, onset-to-imaging time, and blood pressure at admission were assessed. Leakage sign-positive patients were significantly older, more frequently underwent antithrombotic therapy, and exhibited larger hematomas, a higher incidence of spot sign(s), a greater need for surgical intervention, and worse outcomes than their leakage sign-negative counterparts. Leakage sign was detectable within 5 hours of onset. In putaminal hemorrhage, hematoma size demonstrated a significant time-dependent increase, particularly in patients who were leakage sign-positive. Moreover, in leakage sign-positive putaminal hemorrhage, admission systolic blood pressure was strongly correlated with hematoma size, suggesting a synergistic effect between hypertension and ongoing bleeding. In contrast, there was no significant correlation between time and hematoma size in thalamic or subcortical hemorrhages, although trends were noted in subcortical cases. These findings indicate that leakage sign positivity reflects ongoing hyperacute bleeding, with diagnostic validity limited to within 5 hours of onset. Early detection of leakage sign, especially in cases of putaminal hemorrhage, may help identify high-risk patients who could benefit from aggressive interventions to mitigate hematoma expansion and improve outcomes.

Intracerebral hemorrhage is a severe type of stroke with high morbidity and mortality. Accurate assessment of hemorrhage phase is essential for determining treatment strategies, but magnetic resonance imaging evaluation remains subjective and lacks standardized criteria. This study aimed to create an objective method for estimating the phase of intracerebral hemorrhage using multi-sequence magnetic resonance imaging with 6 sequences: T1-weighted imaging, T2-weighted imaging, diffusion-weighted imaging, apparent diffusion coefficient map, fluid-attenuated inversion recovery, and T2 star-weighted magnetic resonance angiography. We retrospectively analyzed 56 patients with intracerebral hemorrhage. Magnetic resonance images used in this study were acquired using GE 1.5T scanners. Relative signal intensities were calculated using the pons as a reference, and a hemorrhage map was generated using color-coding pixels according to the 5 hemorrhage phases. Seven observers performed visual evaluations under 2 conditions: conventional image sets and hemorrhage maps. Diagnostic performance was assessed using precision-recall curves, average precision, and mean average precision. Interobserver agreement was evaluated using Fleiss' κ coefficient. The mean average precision of visual evaluation with the hemorrhage map was significantly higher than that of visual evaluation with original images (0.81 vs. 0.57, p < 0.01). Visual evaluation with hemorrhage map achieved "Almost perfect agreement" (κ = 0.85), whereas visual evaluation with original images demonstrated only "Slight agreement" (κ = 0.06). This study developed a novel diagnostic support method for estimating intracerebral hemorrhage phase using multi-sequence magnetic resonance imaging. By visualizing relative signal intensity as a color-coded hemorrhage map, the proposed method significantly improved both diagnostic accuracy and interobserver agreement compared with conventional visual evaluation.

Giant colloid cysts are rare, benign lesions typically located in the third ventricle, accounting for approximately 2% of primary brain tumors and 15%-20% of intraventricular masses. Although small colloid cysts are relatively common, giant colloid cysts measuring over 3 cm are exceedingly rare and pose significant surgical challenges due to their size and critical anatomical location. This study retrospectively analyzes a series of 5 cases of giant colloid cysts from our local experience, in addition to a comprehensive literature review including 38 studies comprising 48 patients. Surgical approaches evaluated included transcallosal and transcortical craniotomy, endoscopic resection, and stereotactic aspiration. Complete cyst excision was achieved in 44 (83.0%) cases. Postoperative complications included seizures, hemiparesis, hydrocephalus, and cognitive dysfunction, though most patients demonstrated favorable recovery, particularly following complete excision. Our findings suggest that open craniotomy provides the highest rates of complete resection and remains preferable for very large, adherent, or anatomically complex giant colloid cysts, whereas endoscopic resection offers a minimally invasive alternative with acceptable outcomes in carefully selected cases with favorable ventricular anatomy. This study highlights the importance of timely diagnosis, individualized surgical approach selection, multidisciplinary care, and long-term follow-up to optimize patient outcomes and minimize complications.

This study aimed to describe the clinical characteristics of patients with human immunodeficiency virus-related brain lesions who underwent neurosurgical procedures in the antiretroviral therapy era. We retrospectively analyzed 27 neurosurgical procedures in 23 patients with human immunodeficiency virus from January 2013 to December 2023. The mean ages at human immunodeficiency virus diagnosis and surgery were 46.2 ± 12.7 years and 50.8 ± 13.8 years, respectively. At human immunodeficiency virus diagnosis, 18 patients (78.3%) met the criteria for acquired immunodeficiency syndrome, and 11 (47.8%) had a cluster of differentiation 4 count of <50 cells/μL. In total, 16 lesions were diagnosed as an acquired immunodeficiency syndrome-defining illness, including primary central nervous system lymphoma (n = 10), and 11 were diagnosed as a non-acquired immunodeficiency syndrome-defining illness. The mean viral load at surgery was higher in the acquired immunodeficiency syndrome-defining illness group (6.1 ± 11.9 × 10⁵ copies/mL) than in the non-acquired immunodeficiency syndrome-defining illness group (1.2 ± 2.8 × 10⁵ copies/mL, p = 0.009). The time from human immunodeficiency virus diagnosis to surgery was shorter in the acquired immunodeficiency syndrome-defining illness group (7.0 ± 25.2 months vs. 50.6 ± 63.8 months, p = 0.003). A significantly greater number of patients with non-acquired immunodeficiency syndrome-defining illness than acquired immunodeficiency syndrome-defining illness had been treated with antiretroviral therapy for >3 months (72.7% vs. 12.5%, respectively; p = 0.003). The introduction of antiretroviral therapy appears to have contributed to a decrease in brain lesions diagnosed as acquired immunodeficiency syndrome-defining illness, with a corresponding increase in those diagnosed as non-acquired immunodeficiency syndrome-defining illness.