田中 里樹

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.

OBJECTIVE: As a solution to the shortage of and overwork among physicians, task shifting and task sharing have been proposed for health-care professionals. This study aimed to investigate the role of nurse practitioners (NPs) in neurovascular interventions and evaluate the validity of task shifting in our institute. METHODS: Medical records from 684 neurovascular intervention cases from 2020 to 2023 were retrospectively reviewed, and the tasks performed by NPs were investigated. Additionally, the procedure times between cases in which NPs acted as the first assistant alongside a physician (NP + physician group) and those in which 2 physicians performed the procedure (physician + physician group) were compared. RESULTS: The main tasks performed by NPs included preoperative checks, assistance during the procedure, postoperative care, the initial handling of complications, and inputting orders. No significant differences in procedure times were found between the NP + physician and physician + physician groups. CONCLUSION: NPs showed potential for task shifting in perioperative neurovascular interventions, particularly in assisting, providing care, inputting orders, and initially handling complications. However, further discussions and improvements are needed regarding task shifting in emergency cases and work arrangements for NPs.

Aneurysm arising from the A1 segment of the anterior cerebral artery is rare. Aneurysm of the A1 segment even being small tend to rupture early. They tend to develop along the with various vascular anomalies of the vessels arising from the A1 segment. Use of computational fluid dynamics and hemodynamic consideration is of importance in this aneurysm. In this report we describe a 57-year-old woman with a small, unruptured A1 segment aneurysm arising from the proximal segment of the posterior surface of A1, and pointing posterior-inferiorly with multiple perforators entangling around for which microsurgical clipping was done. Intraoperative clipping of the aneurysm and salvaging the multiple perforators were challenging. We report a rare case of an A1 segment aneurysm arising from the posterior surface facing with multiple perforators. It is of significance to understand that a small, unruptured A1 aneurysm can arise from the posterior surface of the A1 segment with projection posterior-inferiorly making it deeper in location with multiple perforators entangling it; hence, it is challenging to treat without causing neurological deficits.

BACKGROUND: The superficial temporal artery-middle cerebral artery (STA-MCA) bypass surgery requires an anastomosis of the STA to an MCA with diminished blood flow. However, identifying the precise location of the MCA with reduced flow preoperatively is challenging as it often remains nonvisualized. To address this issue, we developed a novel technique, the area target bypass (ATB) method, to infer the location of the responsible vessel for low-flow areas. OBJECTIVE: The cornerstone of the ATB method lies in the utilization of the vascular fusion map (VFM). The VFM integrates 3D perfusion and 3D vascular images, enabling simultaneous evaluation of cerebral surface vessels and regions with reduced blood flow. This study aimed to assess the efficacy of the STA-MCA bypass surgery adopting the ATB method. METHODS: Between August 2022 and March 2023, we conducted eight STA-MCA bypass surgeries using the ATB method. For each case, the VFM was generated using the MTT and DLY parameters, and blood flow improvement was evaluated based on the VFM score, determined by an average score from seven experts. RESULTS: In all cases, the target vessel was identified either preoperatively or during craniotomy, with postoperative patency of the STA-MCA bypass confirmed. Out of the eight cases, seven demonstrated improved blood flow with a VFM score exceeding 1. No complications were reported. CONCLUSION: The introduction of the ATB method has proven its potential in accurately pinpointing optimal anastomosis sites.