The Japanese Society for Neuroendovascular Therapy Acta Medica Okayama 1882-4072 20 1 2026 Current Status of Middle Meningeal Artery Embolization for Chronic Subdural Hematoma: An International Perspective Including Japan ra.2025-0153 EN Masato Kawakami Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Kenji Sugiu Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Masafumi Hiramatsu Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Jun Haruma Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Ryu Kimura Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yuta Soutome Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Juntaro Fujita Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yuichi Hirata Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Fukiko Baba Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Shota Tanaka Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Middle meningeal artery embolization (MMAE) for chronic subdural hematoma (CSDH) is gaining global prevalence as a minimally invasive treatment aimed at serving as an adjunct to or method of avoiding surgery; however, its optimal positioning remains unclear. This study outlines the current status of MMAE in Japan, Germany, and the United States based on nationwide survey reports, recently published consensus guidelines, and meta-analyses including randomized controlled trials (RCTs) reported in the New England Journal of Medicine (NEJM; EMBOLISE, STEM, and MAGIC-MT) and examines its efficacy and limitations. Real-world clinical data from Japan, Germany, and the United States indicate that MMAE is primarily used as an adjunctive therapy following surgery for older and high-risk or recurrent cases, or as a stand-alone therapy in selected cases to safely reduce the risk of recurrence and reoperation. While a multidisciplinary consensus statement takes a cautious stance that limits MMAE to recurrent or inoperable cases such as those at high risk associated with interrupting antithrombotic medication, the Society of Vascular and Interventional Neurology guidelines published after the RCTs strongly recommend the concurrent use of MMAE with standard therapy in de novo cases. Meta-analyses integrating the 3 NEJM trials and other RCTs showed that MMAE suppressed recurrence and reoperation versus standard treatment, with particularly pronounced effects in the nonsurgical (conservative treatment) group; however, the additive effect was limited in the surgical adjunct group. No improvement in functional outcomes (modified Rankin Scale score) was observed. Cost-effectiveness analyses suggest that, while MMAE reduces reoperations, routine implementation for all cases is difficult to justify economically because of high procedural costs, indicating the need to narrow the indication to populations at high risk of recurrence. In conclusion, although MMAE is an effective treatment option, the current evidence does not support its uniform introduction in all patients with CSDH. Thus, it is necessary to individualize and adapt the indications for specific patient subgroups, such as those at high risk of recurrence or those for whom surgery is difficult. Finally, we propose a pragmatic treatment strategy for MMAE stratified by disease stage (de novo vs. recurrent) and clinical severity to guide the individualized selection of adjunctive and stand-alone embolization. No potential conflict of interest relevant to this article was reported.

Elsevier BV Acta Medica Okayama 2590-1397 28 2025 Flow diverter treatment for internal carotid artery aneurysm following management of distal cerebral aneurysms: Technical note 100540 EN Yuichi Hirata Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Masafumi Hiramatsu Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Kenji Sugiu Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Fukiko Baba Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Juntaro Fujita Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yuta Sotome Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Masato Kawakami Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Ryu Kimura Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yuki Ebisudani Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Jun Haruma Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Tomohito Hishikawa Department of Neurosurgery, Kawasaki Medical School Shota Tanaka Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Background: In recent years, the effectiveness of flow diverters (FDs) for the treatment of intracranial aneurysms has been reported. While FDs are effective, their deployment involves advancing a delivery wire distally, which may pose a risk if a distal aneurysm exists within the same artery. In such cases, the delivery wire could potentially perforate the distal aneurysm. Here, we present two cases of tandem aneurysms in which an internal carotid artery (ICA) aneurysm was treated with an FD following the treatment of a distal cerebral aneurysm. Case description: A 44-year-old woman and a 67-year-old woman underwent magnetic resonance imaging for headache or abducens nerve palsy. In both cases, two aneurysms were revealed: one at the ICA and the other either at the middle cerebral artery or the top of the ICA. Due to the risk of perforation by the delivery wire during FD deployment, the distal aneurysms were treated first—either with surgical neck clipping or stent-assisted coil embolization. One month after the initial treatment, FD placement for the ICA aneurysm was performed as planned without complications in either case. Discussion: This is the first report where tandem aneurysms were successfully treated with treatment for distal cerebral aneurysms, followed by FDs for proximal ICA aneurysms. We emphasize the potential risk of perforation of the distal aneurysm by the delivery wire during FD placement. Conclusion: Treatment of distal cerebral aneurysms beforehand can help ensure the safe and effective use of FDs in patients with tandem aneurysms. No potential conflict of interest relevant to this article was reported.

Japan Stroke Society Acta Medica Okayama 0912-0726 47 6 2025 頭蓋頚椎移行部動静脈瘻の開頭手術時における上腕動脈穿刺による脳血管撮影の有用性 410 412 EN Yuichi Hirata Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Masafumi Hiramatsu Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Susumu Sasada Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Juntaro Fujita Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yuta Sotome Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Masato Kawakami Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Ryu Kimura Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yuki Ebisudani Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Kyohei Kin Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Jun Haruma Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Kenji Sugiu Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Shota Tanaka Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences 頭蓋頚椎移行部動静脈瘻の手術では，異常血管の確認のため術中血管撮影が重要であるが，体位変換時のsheathの固定や撮影血管へのカテーテルの誘導が困難である．今回，頭蓋頚椎移行部動静脈瘻の開頭手術において上腕動脈穿刺によりultra-long sheathを鎖骨下動脈に留置して椎骨動脈撮影（vertebral artery angiography: VAG）を行う方法の有用性を報告する．当院で本血管撮影を施行した症例の患者背景や合併症を評価した．企図した4例，5血管でVAGを施行でき，合併症も認めなかった．体位変換も腹臥位における穿刺部の観察も簡便であり，カテーテルの操作性にも優れ，VAGを容易に施行することができた．また，管球を頭側から移動する際の術野との干渉も最小限に抑えられた．本方法は利点が多く，有用な血管撮影方法であり，頭蓋頚椎移行部動静脈瘻の手術における一助となり得ると考える． No potential conflict of interest relevant to this article was reported.

Journal of Neurosurgery Publishing Group (JNSPG) Acta Medica Okayama 2694-1902 10 13 2025 Endovascular treatment for a symptomatic dissecting ophthalmic artery aneurysm occurring in the orbit: illustrative case CASE25483 EN Kohei Izumihara Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Jun Haruma Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Kenji Sugiu Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Fukiko Baba Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Juntaro Fujita Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yuichi Hirata Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yuta Sotome Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Masato Kawakami Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Ryu Kimura Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Masafumi Hiramatsu Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Shota Tanaka Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences BACKGROUND: Peripheral ophthalmic artery aneurysms (POAAs) arising from the main trunk or branches of the ophthalmic artery (OphA) are extremely rare. However, their epidemiology and optimal management remain poorly understood. The authors report a rare case of a symptomatic POAA caused by arterial dissection that was successfully treated using endovascular therapy, leading to favorable visual recovery. OBSERVATIONS: A 77-year-old woman presented with sudden-onset visual impairment in the right eye. Ophthalmological examination revealed a defect in the right visual field. CT angiography revealed a fusiform aneurysm in the right intraorbital OphA. Digital subtraction angiography revealed a pearl and string sign, consistent with a dissecting aneurysm. A balloon test occlusion (BTO) of the OphA origin confirmed collateral circulation from the external carotid artery. Internal trapping of the OphA was performed under general anesthesia. Postoperatively, the patient’s visual function gradually improved, and complete recovery was achieved within 3 months. LESSONS: Although POAAs are exceptionally rare, they may lead to significant visual dysfunction owing to optic nerve compression. When visual symptoms are present, prompt intervention may reverse the symptoms. Preoperative assessment of collateral circulation using BTO is essential for treatment planning. Internal trapping may be an effective strategy when sufficient collateral flow is confirmed. No potential conflict of interest relevant to this article was reported.

Japan Neurosurgical Society Acta Medica Okayama 2188-4226 12 2025 Endovascular Thrombectomy for Large Vessel Occlusion in a Patient on Venoarterial Extracorporeal Membrane Oxygenation: A Case Report 445 451 EN Yuki EBISUDANI Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Masafumi HIRAMATSU Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Keiichiro IWASAKI Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Kenji SUGIU Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Jun HARUMA Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Ryu KIMURA Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Masato KAWAKAMI Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yuta SOTOME Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Takahiro NISHIHARA Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Shinsuke YUASA Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Shota TANAKA Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Extracorporeal membrane oxygenation is utilized in the treatment of severe acute cardiac failure and respiratory failure. While it provides the advantage of oxygenating blood through extracorporeal circulation, it also carries risks of intracranial ischemic and hemorrhagic complications due to the continuous presence of artificial materials within the body. We encountered a case in which venoarterial extracorporeal membrane oxygenation was initiated for fulminant myocarditis, and the patient subsequently developed a large vessel occlusion. The diagnosis was confirmed using perfusion computed tomography. A visible thrombus was observed on the arterial cannula of the extracorporeal membrane oxygenation circuit, and the large vessel occlusion was determined to have been caused by thromboembolism. An immediate extracorporeal membrane oxygenation circuit exchange was performed, followed by endovascular thrombectomy. The patient experienced no perioperative complications and achieved a favorable neurological outcome. Endovascular thrombectomy in extracorporeal membrane oxygenation patients requires careful perioperative management and should be promptly performed in eligible cases of thromboembolic events. Furthermore, because patients on extracorporeal membrane oxygenation are often sedated and under intensive systemic management, regular neurological assessments and intracranial monitoring are essential for the early detection of intracranial pathologies. No potential conflict of interest relevant to this article was reported.

Okayama University Medical School Acta Medica Okayama 0386-300X 79 5 2025 The Utility of a Preoperative 3D Imaging Analysis System for Trigonal Meningioma 387 392 EN Yusuke Mori Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yoshihiro Otani Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Ryo Omae Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Shuichiro Hirano Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Joji Ishida Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Kentaro Fujii Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Jun Haruma Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Masafumi Hiramatsu Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Toshi Matsushita Division of Radiological Technology, Okayama University Hospital Fumiyo Higaki Department of Radiology, Medical Development Field, Okayama University Kenji Sugiu Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Shota Tanaka Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Case Report 10.18926/AMO/69440 Trigonal meningiomas are rare and pose surgical challenges due to their deep location and proximity to critical neuroanatomical structures. We present the case of a 67-year-old woman with a growing trigonal meningioma successfully resected with guidance by a preoperative 3D imaging analysis system. Integration of CT and MRI including diffusion tensor imaging (DTI) enabled precise mapping of the optic radiation, guiding a middle temporal gyrus approach. Preoperative embolization reduced tumor vascularity, facilitating gross total resection with minimal blood loss. This case highlights the effectiveness of preoperative 3D imaging systems in optimizing surgical planning and improving outcomes in complex neurosurgical cases. No potential conflict of interest relevant to this article was reported.

Japan Neurosurgical Society Acta Medica Okayama 0470-8105 65 9 2025 Real-world Experience of Embolization for Intracranial Tumors in Japan: Analysis of 2,756 Cases from Japanese Registry of NeuroEndovascular Therapy 4 396 406 EN Jun HARUMA Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Kenji SUGIU Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Tomohito HISHIKAWA Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yuta SOUTOME Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yuki EBISUDANI Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Ryu KIMURA Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Hisanori EDAKI Department of Neurosurgery, Kawasaki Medical School Masato KAWAKAMI Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Satoshi MURAI Department of Neurosurgery, Kawasaki Medical School Masafumi HIRAMATSU Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Shota TANAKA Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Tetsu SATOW Department of Neurosurgery, Kindai University Koji IIHARA Department of Neurosurgery, National Cerebral and Cardiovascular Center Hirotoshi IMAMURA Department of Neurosurgery, National Cerebral and Cardiovascular Center Akira ISHII Department of Neurosurgery, Juntendo University Graduate School of Medicine Yuji MATSUMARU Department of Neurosurgery, Institute of Medicine, University of Tsukuba Chiaki SAKAI Department of Neurosurgery, Kyoto University Shinichi YOSHIMURA Department of Neurosurgery, Hyogo Medical University Nobuyuki SAKAI Department of Neurological Surgery, Shimizu Hospital Japanese Registry of Neuroendovascular Therapy (JR-NET) Investigators Embolization of intracranial tumors is predominantly performed in Japan, primarily before neurosurgical resection. The Japanese Registry of NeuroEndovascular Therapy (JR-NET) Study Group, established in 2005, aims to clarify the factors influencing the outcomes of neuroendovascular treatment. Japanese Registry of NeuroEndovascular Therapy 4 is a nationwide, multicenter retrospective observational study that evaluates real-world data on intracranial tumor embolization in Japan. Japanese Registry of NeuroEndovascular Therapy 4 is based on data collected from 166 neurosurgical centers in Japan between January 2015 and December 2019. Of 63,230 patients, 2,664 (4.2%) with intracranial tumors underwent embolization. The primary endpoint was the proportion of patients with a modified Rankin scale (mRS) score of 0-2 at 30 days post-procedure. Secondary endpoints included procedure-related complications. Among the 2,664 patients, 61 records lacked sufficient data, leaving 2,603 patients (1,612 females, median age: 61 years [interquartile range 51-71]). The proportion of patients with mRS scores ≤2 at 30 days after the procedure was 86.9%. The overall incidence of procedure-related complications was 4.8%, with 1.8% hemorrhagic, 2.0% ischemic, and 1.0% classified as other complications. In the multivariate analysis, general anesthesia and embolization of vessels other than the external carotid artery were identified as risk factors for the development of complications. Meningioma cases had a complication rate of 4.3%, with major complications occurring in 3.5%. Hemangioblastoma cases had a 14.9% complication rate, with major complications at 9.9%. Japanese Registry of NeuroEndovascular Therapy 4 provides comprehensive real-world data on intracranial tumor embolization in Japan, identifying risk factors to inform and improve the safe practice of intracranial tumor embolization in neuroendovascular therapy. No potential conflict of interest relevant to this article was reported.

Japan Neurosurgical Society Acta Medica Okayama 0470-8105 65 7 2025 Nationwide Survey of Middle Meningeal Artery Embolization for Chronic Subdural Hematoma in Japan 319 325 EN Satoshi MURAI Department of Neurosurgery, Kawasaki Medical School Yuki EBISUDANI Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Jun HARUMA Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Masafumi HIRAMATSU Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Tomohito HISHIKAWA Department of Neurosurgery, Kawasaki Medical School Tetsu SATOW Department of Neurosurgery/Stroke Center, Kindai University Hospital Kenji SUGIU Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences 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. No potential conflict of interest relevant to this article was reported.

Japan Neurosurgical Society Acta Medica Okayama 2188-4226 12 2025 Safety of Adenosine-assisted Clipping Surgery for Unruptured Cerebral Aneurysms: Interim Results of a Single-center, Single-arm Study 115 119 EN Tomohito HISHIKAWA Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Satoshi MURAI Department of Neurosurgery, Kawasaki Medical School Masafumi HIRAMATSU Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Jun HARUMA Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yuki EBISUDANI Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Takao YASUHARA Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Kenji SUGIU Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Kazuyoshi SHIMIZU Department of Anesthesiology and Resuscitology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Koji NAKAGAWA Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Aya KIMURA-ONO Center for Innovative Clinical Medicine, Okayama University Hospital Katsuyuki HOTTA Center for Innovative Clinical Medicine, Okayama University Hospital Hiroshi MORIMATSU Department of Anesthesiology and Resuscitology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Isao DATE Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences The aim of this single-center, single-arm study was to evaluate the safety of adenosine-assisted clipping surgery for unruptured cerebral aneurysms. Five patients underwent aneurysmal clipping during adenosine-induced hypotension at ≤60 mmHg. The mean age of patients was 63.4±8.5 years, and the mean aneurysm size was 5.3±1.1 mm. The prevalence of patients with modified Rankin Scale scores of zero 30 days after surgery was 100%. The degree of aneurysm obliteration was complete in 4 patients and residual dome in 1 patient. The mean total dosage of adenosine was 37.4±18.8 mg. The mean duration of systolic blood pressure at ≤60 mmHg was 64.2±28.3 secs. No patients exhibited paroxysmal atrial fibrillation within 24 hours after adenosine administration or elevation of high-sensitivity cardiac troponin T on postoperative day 1. There was no reduction in either motor-evoked or somatosensory-evoked potential amplitude during surgery. Adenosine-induced hypotension is a safe procedure in clipping surgery for unruptured cerebral aneurysms. No potential conflict of interest relevant to this article was reported.

Elsevier BV Acta Medica Okayama 1878-8750 195 2025 Utility of Surgical Simulation for Tubular Retractor Surgery Using Three-Dimensional Printed Intraventricular Tumor Models: Case Series 123743 EN Ryo Omae Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Ryu Kimura Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yoshihiro Otani Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Jun Haruma Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Tomoya Saijo Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Juntaro Fujita Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Shohei Nishigaki Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Ryosuke Ikemachi Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Shuichiro Hirano Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Joji Ishida Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Kentaro Fujii Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Takao Yasuhara Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Shota Tanaka Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Objective: The utility of the tubular retractor for deep-seated tumors, including intraventricular tumors, has recently been reported. However, the surgical field’s depth and narrowness can lead to blind spots, and it is crucial to prevent damage to the cortex and white matter fibers in eloquent areas. Therefore, preoperative simulation is critical for tubular retractor surgery. In this study, we investigated the benefits of threedimensional (3D)-printed intraventricular tumor models for tubular retractor surgery. Methods: Nine patients with intraventricular central neurocytoma who underwent tubular retractor surgery at our institution between March 2013 and August 2023 were retrospectively reviewed. Fusion images and 3D-printed intraventricular tumor models were developed from preoperative computed tomography (CT) and magnetic resonance imaging (MRI). The puncture points of the tubular retractor were simulated using fusion images and 3D-printed intraventricular tumor models by 11 neurosurgeons (3 experts in brain tumors, 2 experts in areas other than brain tumors, and 6 residents). The dispersion of puncture points among 8 neurosurgeons (excluding brain tumor experts) was compared in each simulation model. Results: These cases were categorized into two groups based on the dispersion of puncture points simulated by fusion images. Puncture point dispersion was markedly smaller in all cases when using 3D-printed intraventricular tumor models compared to simulations solely based on fusion images. Conclusions: In intraventricular tumor surgery using a tubular retractor, 3D-printed intraventricular tumor models proved more beneficial in preoperative simulation compared to fusion images. No potential conflict of interest relevant to this article was reported.

The Japanese Society for Neuroendovascular Therapy Acta Medica Okayama 1882-4072 19 1 2025 Non-Sinus-Type Dural Arteriovenous Fistula at the Foramen Magnum: A Review of the Literature ra.2023-0019 EN Masafumi Hiramatsu Department of Neurological Surgery, Okayama University Faculty of Medicine, Dentistry and Pharmaceutical Sciences Tomohiko Ozaki Department of Neurosurgery, National Hospital Organization Osaka National Hospital Rie Aoki Department of Neurosurgery, Tokai University Hachioji Hospital Shinri Oda Department of Neurosurgery, Tokai University Hachioji Hospital Jun Haruma Department of Neurological Surgery, Okayama University Faculty of Medicine, Dentistry and Pharmaceutical Sciences Tomohito Hishikawa Department of Neurological Surgery, Okayama University Faculty of Medicine, Dentistry and Pharmaceutical Sciences Kenji Sugiu Department of Neurological Surgery, Okayama University Faculty of Medicine, Dentistry and Pharmaceutical Sciences Isao Date Department of Neurological Surgery, Okayama University Faculty of Medicine, Dentistry and Pharmaceutical Sciences Dural arteriovenous fistula (dAVF) of the foramen magnum (FM) region is rare. Moreover, the terminology of dAVF is very confusing in this region. In the narrow sense, the FM dAVF is the non-sinus-type dAVF with direct venous reflux to the medulla oblongata or spinal cord via the bridging veins (BVs) of the FM. Previous literature was systematically reviewed to investigate the clinical characteristics, angioarchitecture, and effective treatment of the FM dAVF. From the literature review, almost all the feeders of FM dAVF were dural branches. Spinal pial arteries were rarely involved as the feeder. All lesions had venous reflux to the medulla oblongata via medullary BVs. The FM dAVF is characterized by a significant male predominance and a high incidence of aggressive symptoms. The most common symptom is congestive myelopathy, followed by hemorrhage. The FM dAVF differs from the craniocervical junction (CCJ) arteriovenous fistula (AVF) and is similar to the thoracolumbar spinal dAVF. Direct surgery for the FM dAVF is effective and safe. Endovascular treatment for the FM dAVF may be more effective and has lower complication rates than that for the CCJ AVF. No potential conflict of interest relevant to this article was reported.

Wiley Acta Medica Okayama 2052-8817 11 1 2024 Characteristics and outcomes of subarachnoid hemorrhage from vertebral artery dissection: A comparative study with other non-traumatic etiologies e70031 EN Shu Oshita Okayama University Medical School Tetsuya Yumoto Department of Emergency, Critical Care, and Disaster Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Shunta Jinno Department of Emergency, Critical Care, and Disaster Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Ippei Matsuo Department of Emergency, Critical Care, and Disaster Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Takashi Hongo Department of Emergency, Critical Care, and Disaster Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Hiromichi Naito Department of Emergency, Critical Care, and Disaster Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Masafumi Hiramatsu Department of Neurological Surgery, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Jun Haruma Department of Neurological Surgery, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Kenji Sugiu Department of Neurological Surgery, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Shota Tanaka Department of Neurological Surgery, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Atsunori Nakao Department of Emergency, Critical Care, and Disaster Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Aim: Vertebral artery dissection (VAD) is a rare cause of non-traumatic subarachnoid hemorrhage (SAH) with significant clinical implications. This study compared the clinical characteristics and outcomes of SAH from intracranial VAD rupture to those from other etiologies, primarily aneurysmal rupture. Methods: This single-center retrospective cohort study at Okayama University Hospital included patients with non-traumatic SAH diagnosed between 2019 and 2023. Patients were categorized into "VAD rupture" and "other etiologies" groups. The main outcome was clinical presentation and symptoms. Additional outcomes included ICU mortality, in-hospital mortality, and unfavorable outcomes at discharge and 6 months, defined as a modified Rankin Scale score of 3-6. Results: A total of 66 patients were included, with 14 in the VAD rupture group and 52 in the other etiologies group. The VAD rupture group was younger (median age 49 vs. 64 years, p = 0.003) and had a higher incidence of out-of-hospital cardiac arrest (42.9% vs. 9.6%, p = 0.011). Preceding headache was more common in the VAD rupture group (78.6% vs. 11.5%, p < 0.001), with a median duration of 36 h before presentation. ICU and in-hospital mortality was higher in the VAD rupture group (both 50.0% vs. 19.3%, p = 0.019). No significant differences were found in unfavorable neurological outcomes at hospital discharge and 6 months. Conclusions: VAD-related SAH often presents with prodromal headaches, severe symptoms like out-of-hospital cardiac arrest, and higher ICU and in-hospital mortality than other SAH causes, though long-term outcomes are similar. Larger, prospective studies are needed to refine interventions. No potential conflict of interest relevant to this article was reported.

The Japanese Society for Neuroendovascular Therapy Acta Medica Okayama 1882-4072 17 9 2023 Questionnaire Survey of Neurointerventional Simulation Training in the Japanese Society for Neuroendovascular Therapy 181 187 EN Yuki Ebisudani Department of Neurological Surgery, Okayama University Faculty of Medicine, Dentistry and Pharmaceutical Sciences Kenji Sugiu Department of Neurological Surgery, Okayama University Faculty of Medicine, Dentistry and Pharmaceutical Sciences Satoshi Murai Department of Neurological Surgery, Okayama University Faculty of Medicine, Dentistry and Pharmaceutical Sciences Jun Haruma Department of Neurological Surgery, Okayama University Faculty of Medicine, Dentistry and Pharmaceutical Sciences Masafumi Hiramatsu Department of Neurological Surgery, Okayama University Faculty of Medicine, Dentistry and Pharmaceutical Sciences Tomohito Hishikawa Department of Neurological Surgery, Okayama University Faculty of Medicine, Dentistry and Pharmaceutical Sciences Isao Date Department of Neurological Surgery, Okayama University Faculty of Medicine, Dentistry and Pharmaceutical Sciences Objective: Simulation training has focused on education and practical training. However, the adoption rate of neurointerventional simulation training in Japan is unknown. Therefore, we sent a questionnaire survey form to consulting specialists from the Japanese Society for Neuroendovascular Therapy (JSNET) to clarify the actual simulation training situation and compare the differences between university hospitals and general hospitals in Japan. Methods: The questionnaire survey was conducted in 243 neurosurgical training facilities that had JSNET consulting specialists between May 31, 2021 and July 31, 2021. The questionnaire survey forms were distributed by Google Forms. Results: A total of 162 facilities responded to the survey (response rate: 66.7%; 35.2% from university hospitals and 64.8% from general hospitals). The adoption rate for simulation training was 53.7%, and it was significantly higher in the university hospitals than in the general hospitals (64.9% vs. 47.6%, p = 0.035). On the simulation effectiveness survey, more than 80% of respondents answered that the simulation training was a useful tool for upskill training. The open-ended question on interventional simulation training showed that there are limiting factors such as financial constraints. Additionally, respondents expressed a desire for a standard neurointerventional simulation training and education program. Conclusion: The adoption rate for simulation training was 53.7% in the training facilities of JSNET, and it was higher in the university hospitals than in the general hospitals. Most of the respondents answered that simulation training is an effective tool to improve neurointerventional skills. They also requested the establishment of simulation training programs and simulation tools. No potential conflict of interest relevant to this article was reported.

Elsevier BV Acta Medica Okayama 1878-8750 159 2022 A New Method of Intracranial Aneurysm Modeling for Stereolithography Apparatus 3D Printer: The “Wall-Carving Technique” Using Digital Imaging and Communications in Medicine Data e113 e119 EN Jun Haruma Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Kenji Sugiu Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Minori Hoshika Department of Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Masafumi Hiramatsu Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Tomohito Hishikawa Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Satoshi Murai Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Kazuhiko Nishi Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yoko Yamaoka Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yu Sato Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yuki Ebisudani Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Hisanori Edaki Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Ryu Kimura Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Isao Date Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences OBJECTIVE: To assess the ability of the "wall-carving (WC) image technique", which uses vascular images from 3-dimensional digital subtraction angiograms (3DDSAs). Also, to verify the accuracy of the resulting 3D-printed hollow models of intracranial aneurysms. METHODS: The 3DDSA data from 9 aneurysms were processed to obtain volumetric models suitable for the stereolithography apparatus. The resulting models were filled with iodinated contrast media. 3D rotational angiography of the models was carried out, and the aneurysm geometry was compared with the original patient data. The accuracy of the 3D-printed hollow models' sizes and shapes was evaluated using the nonparametric Wilcoxon signed-rank test and the Dice coefficient index. RESULTS: The aneurysm volumes ranged from 34.1 to 4609.8 mm 3 (maximum diameters 5.1-30.1 mm), and no statistically significant differences were noted between the patient data and the 3D-printed models (P = 0.4). Shape analysis of the aneurysms and related arteries indicated a high level of accuracy (Dice coefficient index value: 88.1%-97.3%; mean + SD: 93.6% +/- 2.5%). The vessel wall thickness of the 3D-printed hollow models was 0.4 mm for the parent and 0.2 mm for small branches and aneurysms, almost the same as the patient data. CONCLUSIONS: The WC technique, which involves volume rendering of 3DDSAs, can provide a detailed description of the contrast enhancement of intracranial vessels and aneurysms at arbitrary depths. These models can provide precise anatomic information and be used for simulations of endovascular treatment. No potential conflict of interest relevant to this article was reported.