田中 里樹

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.

BACKGROUND: This study evaluated the safety and efficacy of a treatment strategy for Posterior communicating artery (PCOM) aneurysms using first-line Woven EndoBridge (WEB), supplemented by Flow diverter (FD) in selected cases. METHODS: This retrospective study included patients who underwent endovascular treatment for PCOM aneurysms between January 2021 and March 2025. Aneurysms were categorized as fetal or non-fetal. A first-line WEB strategy was adopted when morphology was suitable. Radiological and clinical outcomes were assessed. RESULTS: Forty-six PCOM aneurysms met the criteria: 14 fetal-type and 32 non-fetal-type. All previously untreated fetal-type aneurysms were treated with WEB (n = 9). In the non-fetal group, the initial treatments included WEB (n = 14), FD (n = 10), and coiling (n = 4). All recurrent fetal-type aneurysms were retreated with FD (n = 5), whereas non-fetal recurrences were managed with FD (n = 3) or coiling (n = 1), depending on prior treatment. At a median follow-up of 21 months, complete occlusion was achieved in 66.7% of fetal-type and 59.4% of non-fetal-type aneurysms (P = 0.739), and adequate occlusion was achieved in 75.0% and 90.6%, respectively (P = 0.321). Retreatment was required in two cases (4.3%): one in the fetal group (7.1%) and one in the non-fetal group (3.1%) (p = 0.512). No modified Rankin Scale worsening or major complications occurred. No significant differences in treatment efficacy were observed among modalities selected under the WEB first-line strategy. CONCLUSION: A first-line WEB strategy is safe and effective for PCOM aneurysms, including fetal-type variants, with outcomes for fetal-type aneurysms comparable to non-fetal-type aneurysms.

BACKGROUND: Ruptured wide-necked or multi-lobulated intracranial aneurysms pose a challenge in the acute phase of subarachnoid hemorrhage (SAH), in which antiplatelet therapy is generally contraindicated. The Woven EndoBridge (WEB) device enables intrasaccular occlusion without requiring antiplatelet agents. However, the treatment of multilobulated aneurysms in this setting remains technically demanding. CASE DESCRIPTION: An octogenarian patient presented with a poor-grade SAH due to a ruptured multilobulated aneurysm of the right middle cerebral artery (MCA) accompanied by intracerebral and subdural hematomas. Emergency endovascular treatment was performed using dual-horizontal WEB devices, each deployed in a separate lobule. Antiplatelet therapy was not administered. Subsequently, a neuroendoscopic hematoma evacuation was performed. Postoperative imaging confirmed complete exclusion of the aneurysm and resolution of the hematoma. The patient showed neurological improvement and was transferred for rehabilitation with acceptable clinical outcomes. CONCLUSION: This case illustrates the feasibility of combining dual WEB deployment with subsequent neuroendoscopic hematoma evacuation during the acute phase of SAH. This strategy may be a viable treatment option for ruptured multilobulated MCA aneurysms in older adults when conventional approaches are unsuitable.

BACKGROUND: This report presents a rare case of trigeminal neuralgia (TN) caused by a radicular arteriovenous fistula (AVF). CASE DESCRIPTION: A 58-year-old woman presented with severe pain in the right lower jaw, typical of TN. Magnetic resonance imaging showed a vascular signal near the trigeminal nerve. Direct surgery revealed tortuous vessels on the dorsal surface of the nerve, with no offending vessels identified at the root entry zone. Digital subtraction angiography (DSA) confirmed a radicular AVF fed by the trigeminocerebellar artery, with venous drainage into the superior petrosal sinus through the petrosal vein. Endovascular embolization with n-butyl cyanoacrylate resulted in complete obliteration of the fistula and symptom resolution. Although a small pontine infarction occurred, no long-term deficits were observed. Follow-up DSA confirmed no recurrence. CONCLUSION: To the best of our knowledge, this represents the first documented case of a trigeminal radicular AVF, highlighting the importance of recognizing vascular anomalies and efficacy of endovascular treatment in managing TN.

BACKGROUND: Aneurysmal subarachnoid hemorrhage caused by cerebral aneurysm rupture has a poor prognosis, with mortality exceeding 30% despite treatment advancements. Surgical neck clipping remains the standard for preventing rupture, but intraoperative rupture rates vary significantly (3-50%) and are influenced by vascular complexity and technical challenges. Thinning of the vascular wall near the aneurysm neck, particularly with microaneurysm formation, has emerged as a significant risk factor, yet these changes often go undetected in preoperative imaging. OBJECTIVE: This study aimed to evaluate the utility of computational fluid dynamics (CFD) analysis for predicting microaneurysm formation in the parent artery adjacent to unruptured cerebral aneurysms, using the parent artery radiation sign (PARS) as a predictive marker. METHODS: We conducted a single-center, retrospective observational study of 89 patients with unruptured middle cerebral artery (MCA) aneurysms treated with neck clipping from May 2020 to April 2022. Based on preoperative three-dimensional computed tomography angiography (3D-CTA), CFD analysis identified PARS through specific hemodynamic indicators. Intraoperative findings were analyzed and compared between PARS-positive and PARS-negative groups. The sensitivity and specificity of PARS for predicting microaneurysm formation were investigated. RESULTS: Of the 87 aneurysms analyzed, 25 (28.7%) were PARS-positive, and 62 (71.3%) were PARS-negative. Microaneurysms were identified intraoperatively in nine cases, eight of which were in the PARS-positive group. The sensitivity and specificity of PARS for detecting microaneurysms were 89 and 78%, respectively. The positive likelihood ratio was 4.1, while the negative likelihood ratio was 0.142. CONCLUSION: CFD analysis using PARS offers a reliable method for predicting microaneurysm formation in the parent artery, potentially guiding surgical planning and reducing intraoperative rupture risk. While promising, these findings are limited by the retrospective, single-center design, highlighting the need for further research in larger, multicenter cohorts. Incorporating CFD analysis into preoperative assessment could significantly enhance the safety and outcomes of neck clipping procedures for unruptured cerebral aneurysms.