Intramedullary spinal cord tumors/lesions are rare, but they present significant surgical challenges owing to the high risk of spinal cord injury during myelotomy. Conventional techniques are often limited by positional discrepancies and anatomical variations. Indocyanine green videoangiography provides real-time fluorescence imaging of the lesion vasculature. This study aimed to evaluate the safety and efficacy of intraoperative indocyanine green videoangiography and to determine which pathological subtypes are most amenable to this technique. We enrolled patients with intramedullary spinal cord tumors, excluding those with hemangioblastoma. A 2-step approach was used for lesion localization: initial delineation using conventional methods, followed by indocyanine green videoangiography, in which indocyanine green was administered intravenously, and lesion boundaries were re-marked using fluorescence imaging. The outcome measure was the prediction error distance between conventional localization and indocyanine green videoangiography localization, and the impact of lesion characteristics on localization accuracy. This study included 15 patients with intramedullary spinal cord tumors. The mean prediction error distance was 3.63 mm for the conventional method and 2.77 mm for indocyanine green videoangiography. The mean prediction error distance difference between the 2 methods was 0.87 mm (p = 0.047). Tumor size correlated with greater reductions in prediction error distance using indocyanine green videoangiography (height, p = 0.005). Larger tumors (23.4 mm in height) tended to demonstrate a mean prediction error distance reduction of 2.0 mm (p = 0.085). Minor adverse events that could be related to indocyanine green videoangiography were observed in 3 cases, all of which resolved spontaneously. Intraoperative indocyanine green videoangiography performed before myelotomy may improve the accuracy of tumor localization with minimal risk in patients with intramedullary spinal cord tumors/lesions. It might be particularly effective at minimizing errors in large intramedullary spinal cord tumors. By reducing unnecessary myelotomy, indocyanine green videoangiography may improve surgical outcomes.

Vertebral artery dissection is a rare but potentially life-threatening condition. However, many cases of mild vertebral artery dissection-an early disease stage-may be overlooked. 3-dimensional T1-weighted black-blood magnetic resonance imaging has recently emerged as a promising diagnostic tool, yet it remains underutilized. This study investigated the impact of vertebral artery dissection screening in patients presenting with headache, the most common chief complaint encountered in general neurosurgery outpatient clinics, and an initial symptom of vertebral artery dissection, in a real-world clinical setting. We retrospectively reviewed 3,049 consecutive patients with headache who visited a neurosurgical outpatient center in Chiba, Japan (October 2021-October 2023). In the first year, 1,527 patients underwent brain magnetic resonance imaging and magnetic resonance angiography. In the second year, 1,522 patients received these examinations as well as brain and neck black-blood magnetic resonance imaging. Vertebral artery dissection detection rates were compared between the 2 groups.

Vertebral artery dissection was diagnosed in 0.5% and 1.6% of the former and latter groups, respectively (relative risk: 3.42, 95% confidence interval 1.48-7.92, p = 0.003), indicating an over threefold increase in detection. Among patients with intracranial vertebral artery dissection, 96% reported occipital headache rather than nonspecific/generalized headache. Among high-risk individuals aged 40-55 years with occipital or posterior neck pain, the detection rate reached 7.5%. Vertebral artery dissection accounted for 93% of head and neck arterial dissections. The addition of black-blood magnetic resonance imaging significantly improved early detection and may enhance screening accuracy for patients presenting with headache at elevated risk.

Tractography is a technique for visualizing the trajectories of white matter pathways. The most widely used model, the diffusion tensor imaging, assumes a single fiber orientation within each voxel. In contrast, the constrained spherical deconvolution model enables the estimation of multiple fiber orientations. Recently, constrained spherical deconvolution was added to a widely used neurosurgical navigation platform alongside the diffusion tensor imaging model, allowing both approaches to be applied within the same clinical environment. In this study, we compared the volumes of white matter tracts reconstructed using these 2 models. Magnetic resonance imaging data from 37 patients were used to reconstruct 5 white matter tracts-the corpus callosum, the bilateral inferior fronto-occipital fasciculi, and the bilateral corticospinal tracts. Volumetric and visual analyses were conducted to assess differences in tract reconstruction between constrained spherical deconvolution and diffusion tensor imaging. Across all bundles, constrained spherical deconvolution consistently yielded significantly greater tract volumes, with a mean percentage volume difference of 158.6% (p < 0.001), most prominently in the inferior fronto-occipital fasciculi. Visual assessments favored constrained spherical deconvolution-based reconstructions in approximately 80% of the cases, and volumetric and visual measures demonstrated strong concordance (Spearman's ρ = −0.766, p < 0.001). In contrast, differences between constrained spherical deconvolution and diffusion tensor imaging were less pronounced in the corticospinal tracts. Lowering the fractional anisotropy threshold in diffusion tensor imaging did not improve reconstruction quality and produced anatomically implausible streamlines. Tract type was the primary determinant of inter-method differences (p < 0.001). Integration of constrained spherical deconvolution into clinical navigation can enhance visualization of white matter organization and may improve preoperative planning and risk evaluation in neurosurgical practice.

Flow diverter braid deformation is occasionally observed after flow diverter placement. However, the frequency and clinical significance of flow diverter braid deformation in non-drawn filled tube wire devices remain unclear. This retrospective, single-center study analyzed 139 consecutive patients (median age, 60 years; 82.7% women) who underwent flow diverter placement for intracranial aneurysms between 2017 and 2024. Follow-up angiography and cone-beam computed tomography images were compared with those obtained immediately after flow diverter deployment to identify flow diverter-related morphologic changes. The identified morphologic changes were classified into 4 major patterns (fish mouthing, bump, collapse, and shortening) as flow diverter braid deformation and 2 variants (distal tapering and edge flare) as minor morphologic changes. Cases with fish mouthing or collapse were classified as a high-risk flow diverter braid deformation category because of their association with thromboembolic complications. Flow diverter-related morphologic changes were detected in 31 patients (22.3%), including flow diverter braid deformation in 24 patients (17.3%), at the first angiographic follow-up, and no progression was detected during subsequent observations. The most common pattern was shortening (12.9%), followed by distal tapering (5.0%), and high-risk flow diverter braid deformation was rare (fish mouthing, 1.4%; collapse, 1.4%). Neointimal hyperplasia was more frequent in the flow diverter braid deformation group, whereas the rates of in-stent stenosis, aneurysm occlusion (O'Kelly-Marotta grades C-D), retreatment, and favorable functional outcomes (modified Rankin Scale, 0-2) did not differ significantly between the groups. Younger age and proximal stent oversizing were independent predictors of flow diverter braid deformation. Given the rarity of the high-risk category and the absence of adverse outcomes, flow diverter braid deformation represents a benign and stable morphological change in non-drawn filled tube wire flow diverters.

Temporary zygomatic arch removal (zygomectomy) in the orbitozygomatic approach is sometimes used in surgeries involving complex lesions. Although the orbitozygomatic approach provides wider exposure than the pterional approach, it is more invasive and carries a higher risk of complications. We hypothesized that adequate exposure could be achieved without zygomectomy when the zygomatic arch lies well below the floor of the middle cranial fossa. This study introduces the concept of "Low-set Zygoma" and examines its clinical and anatomical relevance. High-resolution cranial computed tomography scans from 105 adults without craniofacial anomalies (210 sides) were analyzed to measure the vertical distance from the superior margin of the zygomatic arch to the middle cranial fossa floor (middle cranial fossa height). In this study, a Low-set Zygoma was defined as a middle cranial fossa height of ≥ −3.0 mm. Participants were stratified into 2 groups [Low-set Zygoma (≥ −3.0 mm) and non-Low-set Zygoma (< −3.0 mm) ], and demographic variables were assessed using univariate and multivariate statistical analyses. We performed 3 pterional approaches in patients with Low-set Zygoma, where orbitozygomatic approach was typically indicated. Adequate exposure was achieved in all patients, with no complications. Based on computed tomography data, the mean vertical distance from the zygomatic arch to the middle cranial fossa floor was −2.36 mm. Body height was the only independent predictor of a Low-set Zygoma (p = 0.037); individuals shorter than 162.5 cm were significantly more likely to exhibit this anatomical feature. A Low-set Zygoma appears to be a reliable anatomical indicator for avoiding unnecessary zygomectomy and may support more individualized preoperative planning.

Absorbable gelatin sponges are widely used as hemostatic and reconstructive materials in neurosurgery. Global discontinuation of Gelfoam and withdrawal of Spongel from the Japanese market have created an urgent need for alternatives. This study was performed to evaluate the utility of Spongostan as a substitute for Spongel and Gelfoam in sellar floor reconstruction using the fibrin glue-soaked gelatin sponge method.

Two gelatin sponges (Spongel and Spongostan) and 2 fibrin sealants (Beriplast and Bolheal) were combined to prepare 4 fibrin glue-soaked gelatin sponge combinations. Adhesive strength was measured using a tensile strength test according to ASTM F2458-05 and analyzed using 2-way analysis of variance. A retrospective review was also conducted for patients who underwent endoscopic transsphenoidal surgery for pituitary adenoma between May 2024 and October 2025, in which fibrin glue-soaked gelatin sponge prepared with Spongostan was used for sellar floor reconstruction.

Spongostan showed significantly higher adhesive strength than Spongel (F (1,20) = 13.72, p = 0.0014), whereas neither the fibrin sealant type nor the sponge-fibrin sealant interaction was significant (both p = 0.73). In 11 clinical cases (mean age 66 ± 16 years), intraoperative cerebrospinal fluid leakage occurred in 5 cases and postoperative leakage in one case, in a patient who had undergone prior radiotherapy. No hemorrhage, meningitis, or material-related complications occurred. These findings suggest that Spongostan may serve as a feasible alternative to Spongel for fibrin glue-soaked gelatin sponge-based sellar floor reconstruction during endoscopic transsphenoidal surgery.

Perfusion computed tomography predicts and diagnoses delayed cerebral ischemia after subarachnoid hemorrhage, but challenges in precision and interpretation limit its adoption. This study investigated whether tissue time-to-maximum analysis during the peak term of cerebral vasospasm, processed via Rapid Processing of Perfusion and Diffusion, can stratify delayed cerebral ischemia risk in patients with subarachnoid hemorrhage.

In this retrospective cohort study, patients with subarachnoid hemorrhage treated surgically or endovascularly from March 2021 to March 2025 at the Japanese Red Cross Kumamoto Hospital underwent perfusion computed tomography approximately 10 days after the onset. Time-to-maximum parameters were computed via Rapid Processing of Perfusion and Diffusion and analyzed using logistic regression to assess their association with subsequent delayed cerebral ischemia. The primary endpoint was the development of delayed cerebral ischemia.

Of the 181 patients initially screened, 101 were included in the study. The cohort included 81 women, with a mean age of 65 years. Among the 101 patients, 22 developed delayed cerebral ischemia. Compared with those without delayed cerebral ischemia, the delayed cerebral ischemia group had higher preoperative World Federation of Neurosurgical Societies grades and a higher frequency of significant cerebral vasospasm. The volume of time-to-maximum > 4 sec showed the strongest independent association with delayed cerebral ischemia. Receiver operating characteristic analysis identified a threshold of 31 mL for time-to-maximum > 4 sec, yielding a sensitivity of 0.91 and a specificity of 0.96. In multivariable logistic regression adjusting for World Federation of Neurosurgical Societies grade and cerebral vasospasm, time-to-maximum > 4 sec was associated with delayed cerebral ischemia development.

The incorporation of time-to-maximum analysis via Rapid Processing of Perfusion and Diffusion may standardize perfusion computed tomography interpretation and enable delayed cerebral ischemia risk assessment.

Vagus nerve stimulation is an established treatment for refractory epilepsy, but predictors of treatment response remain unclear. Given that left-sided vagus nerve stimulation preferentially modulates the left thalamus and that epileptic networks induce thalamic structural damage, we investigated whether preoperative thalamic volume asymmetry predicts vagus nerve stimulation outcomes. This retrospective study included 17 patients with refractory epilepsy who underwent vagus nerve stimulation implantation. Patients were classified as responders (≥50% seizure reduction at 24 months, n = 9) or non-responders (n = 8). Thalamic volumes were manually segmented on preoperative T2-weighted magnetic resonance imaging by 2 blinded raters, and we used the rater-averaged values to calculate the left/right volume ratio and asymmetry index. The mean thalamic volume ratio (left/right) was significantly higher in responders than non-responders (1.00 [95% confidence interval 0.97-1.03] vs 0.96 [95% confidence interval 0.92-0.99], p = 0.027), and the asymmetry index also differed between groups (0.00 [95% confidence interval −0.015 to 0.017] vs −0.023 [95% confidence interval −0.040 to −0.006], p = 0.027). Inter-rater reliability was acceptable for absolute volumes but was lower for ratio-based asymmetry indices, suggesting that these derived metrics may be more suitable for group-level comparisons than for single-patient prediction. Epileptogenic laterality determined by electroencephalography did not predict thalamic asymmetry. Relative left thalamic volume reduction was associated with poor vagus nerve stimulation treatment response. Assessment of preoperative thalamic asymmetry on routine structural magnetic resonance imaging may represent a candidate biomarker for predicting vagus nerve stimulation efficacy, pending validation in larger cohorts.