Relationship between Shape Retention and X-ray Absorption Value of the Tip of Microcatheters in Neuroendovascular Treatment.

Objective We noticed that the X-ray absorption value of the tip of each microcatheter used for aneurysm treatment varied from product to product. We hypothesized that the differences were caused by variations in the metal's density braid, which could be related to the ability of the tip to retain its shape. Methods The X-ray absorption value of each microcatheter tip was measured. Next, heat forming was performed using a shaping mandrel at 6 mm and 90 degrees to determine whether there was a correlation between the X-ray absorption value and the forming angle. Next, the optimal mandrel angle for forming each microcatheter at 90 degrees was investigated. We also examined the shape retention after 20 times wire insertions into each microcatheter. Conclusion It was found that the higher the X-ray absorption value, the harder it was for the microcatheter to be formed. The mandrel angle required to form 90 degrees was determined by the X-ray absorption value. The higher the X-ray absorption value, the higher the shape retention of the tip shape. The heat formation and shape-retention conditions of the microcatheter tip were correlated with the X-ray absorption value of the metal braid. Even for unknown microcatheters, the optimum shaping conditions can be inferred from the X-ray absorption value.

Platelet-derived Growth Factor Activates Pericytes in the Microvessels of Chronic Subdural Hematoma Outer Membranes.

Angiogenesis is one of the growth mechanisms of chronic subdural hematoma (CSDH). Pericytes have been implicated in the capillary sprouting during angiogenesis and are involved in brain ischemia and diabetic retinopathy. This study examined the pericyte expressions in CSDH outer membranes obtained during trepanation surgery. Eight samples of CSDH outer membranes and 35 samples of CSDH fluid were included. NG2, N-cadherin, VE-cadherin, Tie-2, endothelial nitric oxide synthase (eNOS), platelet-derived growth factor (PDGF) receptor-ß (PDGFR-ß), a well-known marker of pericytes, phosphorylated PDGFR-ß at Tyr751, and ß-actin expressions, were examined using western blot analysis. PDGFR-ß, N-cadherin, and Tie-2 expression levels were also examined using immunohistochemistry. The concentrations of PDGF-BB in CSDH fluid samples were measured using enzyme-linked immunosorbent assay kits. NG2, N-cadherin, VE-cadherin, Tie-2, eNOS, PDGFR-ß, and eNOS expressions in CSDH outer membranes were confirmed in all cases. Furthermore, phosphorylated PDGFR-ß at Tyr751 was also detected. In addition, PDGFR-ß, N-cadherin, and Tie-2 expressions were localized to the endothelial cells of the vessels within CSDH outer membranes by immunohistochemistry. The concentration of PDGF-BB in CSDH fluids was significantly higher than that in cerebrospinal fluid. These findings indicate that PDGF activates pericytes in the microvessels of CSDH outer membranes and suggest that pericytes are crucial in CSDH angiogenesis through the PDGF/PDGFR-ß signaling pathway.

Treatment Outcomes of 94 Cases of Pipeline Embolization Device in a Single Center: Predictive Factors of Incomplete Aneurysm Occlusion.

Objective: This study aimed to report the outcome of an endovascular treatment with a pipeline embolization device (PED) at a single center. We also examined the predictive factors for an incomplete occlusion after the PED placement. Methods: The subjects were 94 patients with 109 aneurysms who underwent the PED placement at our single center from June 2015 to September 2022. As treatment outcomes, we investigated the PED placement success rate, perioperative morbidity and mortality, postoperative cranial nerve improvement rate, and the classification of angiographic result at 6 months after the PED placement. Furthermore, the predictors of an incomplete occlusion were investigated in detail. Results: One hundred nine aneurysms locations were: C1 (9), C2 (30), C3 (15), C4 (53), and C5 (2) in the internal carotid artery segments. Perioperative morbidity, including the asymptomatic ones, occurred in 10 cases (10.6%). Among these 10 cases, the modified Rankin Scale (mRS) improved to preoperative mRS after 90 days in 9 cases except 1 case. On the other hand, no perioperative mortality was observed. The postoperative cranial nerve improvement rate was 84.4%, and 61.7% of patients had a complete occlusion in the follow-up angiography, 6 months after the PED placement. Predictive factors for an incomplete occlusion after the PED placement were the elderly aged 70 years or older (P-value = 0.0214), the elderly aged 75 years or older (P-value = 0.0009), and the use of anticoagulants (P-value = 0.0388) in an univariate analysis. Further, the multivariate analysis revealed that the elderly aged 75 years or older was a predictive factor of an incomplete occlusion in this study. Conclusion: We summarized the outcomes of the PED treatment at our single center. In this study, the elderly aged 75 years or older was a predictive factor of an incomplete occlusion after the PED placement.

Hairball-Like Migration of "Onyx Threads" into the Draining Vein during Transarterial Embolization of a Dural Arteriovenous Fistula: A Case Report and Experimental Validation.

Transarterial embolization using Onyx is a well-established treatment for dural arteriovenous fistulas (DAVFs). However, complications can arise when Onyx migrates into the venous side, impairing the draining veins. We encountered a case where Onyx, injected through the arterial side, strayed into the jugular vein, forming a hairball-like structure. Our study aimed to investigate the underlying mechanism of this unusual phenomenon. We postulated that Onyx precipitates into thread-like shapes when passing through extremely narrow openings. To test this, we extruded Onyx from a syringe through a 27-gauge needle into a silicone tube with flowing water. By varying the flow speed, we observed the hardening behavior of Onyx. Under slow flow, the extruded Onyx quickly solidified at the needle tip, forming a round mass. Conversely, high-speed flow resulted in Onyx being dispersed as small pieces. We successfully replicated the formation of "Onyx threads" under continuous slow flow conditions, similar to our case. This phenomenon occurs when Onyx unexpectedly migrates to the draining vein through a tiny opening during transarterial embolization for arteriovenous shunt diseases. Early recognition and appropriate measures are necessary to prevent occlusive complications in the draining veins and the pulmonary system.

Angiogenesis in the Outer Membrane of Chronic Subdural Hematomas through Thrombin-Cleaved Osteopontin and the Integrin α9 and Integrin ß1 Signaling Pathways.

BACKGROUND: A chronic subdural hematoma (CSDH) is considered to be an inflammatory and angiogenic disease. The CSDH outer membrane, which contains inflammatory cells, plays an important role in CSDH development. Osteopontin (OPN) is an extracellular matrix protein that is cleaved by thrombin, generating the N-terminal half of OPN, which is prominently involved in integrin signal transduction. We explored the expression of the N-terminal half of OPN in CSDH fluid and the expression of integrins α9 and ß1 and the downstream components of the angiogenic signaling pathways in the outer membrane of CSDHs. METHODS: Twenty samples of CSDH fluid and eight samples of CSDH outer membrane were collected from patients suffering from CSDHs. The concentrations of the N-terminal half of OPN in CSDH fluid samples were measured using ELISA kits. The expression levels of integrins α9 and ß1, vinculin, talin-1, focal adhesion kinase (FAK), paxillin, α-actin, Src and ß-actin were examined by Western blot analysis. The expression levels of integrins α9 and ß1, FAK and paxillin were also examined by immunohistochemistry. We investigated whether CSDH fluid could activate FAK in cultured endothelial cells in vitro. RESULTS: The concentration of the N-terminal half of OPN in CSDH fluid was significantly higher than that in the serum. Western blot analysis confirmed the presence of these molecules. In addition, integrins α9 and ß1, FAK and paxillin were localized in the endothelial cells of vessels within the CSDH outer membrane. FAK was significantly phosphorylated immediately after treatment with CSDH fluid. CONCLUSION: Our data suggest that the N-terminal half of OPN in CSDH fluid promotes neovascularization in endothelial cells through integrins α9 and ß1. The N-terminal half of OPN, which is part of the extracellular matrix, plays a critical role in the promotion of CSDHs.

World federation of interventional and therapeutic neuroradiology (WFITN) federation assembly neurointerventional surgery safety checklist.

Over the last 10 years, there has been a rise in neurointerventional case complexity, device variety and physician distractions. Even among experienced physicians, this trend challenges our memory and concentration, making it more difficult to remember safety principles and their implications. Checklists are regarded by some as a redundant exercise that wastes time, or as an attack on physician autonomy. However, given the increasing case and disease complexity along with the number of distractions, it is even more important now to have a compelling reminder of safety principles that preserve habits that are susceptible to being overlooked because they seem mundane. Most hospitals have mandated a pre-procedure neurointerventional time-out checklist, but often it ends up being done in a cursory fashion for the primary purpose of 'checking off boxes'. There may be value in iterating the checklist to further emphasize safety and communication. The Federation Assembly of the World Federation of Interventional and Therapeutic Neuroradiology (WFITN) decided to construct a checklist for neurointerventional cases based on a review of the literature and insights from an expert panel.

National trends in the outcomes of subarachnoid haemorrhage and the prognostic influence of stroke centre capability in Japan: retrospective cohort study.

OBJECTIVES: To examine the national, 6-year trends in in-hospital clinical outcomes of patients with subarachnoid haemorrhage (SAH) who underwent clipping or coiling and the prognostic influence of temporal trends in the Comprehensive Stroke Center (CSC) capabilities on patient outcomes in Japan. DESIGN: Retrospective study. SETTING: Six hundred and thirty-one primary care institutions in Japan. PARTICIPANTS: Forty-five thousand and eleven patients with SAH who were urgently hospitalised, identified using the J-ASPECT Diagnosis Procedure Combination database. PRIMARY AND SECONDARY OUTCOME MEASURES: Annual number of patients with SAH who remained untreated, or who received clipping or coiling, in-hospital mortality and poor functional outcomes (modified Rankin Scale: 3-6) at discharge. Each CSC was assessed using a validated scoring system (CSC score: 1-25 points). RESULTS: In the overall cohort, in-hospital mortality decreased (year for trend, OR (95% CI): 0.97 (0.96 to 0.99)), while the proportion of poor functional outcomes remained unchanged (1.00 (0.98 to 1.02)). The proportion of patients who underwent clipping gradually decreased from 46.6% to 38.5%, while that of those who received coiling and those left untreated gradually increased from 16.9% to 22.6% and 35.4% to 38%, respectively. In-hospital mortality of coiled (0.94 (0.89 to 0.98)) and untreated (0.93 (0.90 to 0.96)) patients decreased, whereas that of clipped patients remained stable. CSC score improvement was associated with increased use of coiling (per 1-point increase, 1.14 (1.08 to 1.20)) but not with short-term patient outcomes regardless of treatment modality. CONCLUSIONS: The 6-year trends indicated lower in-hospital mortality for patients with SAH (attributable to better outcomes), increased use of coiling and multidisciplinary care for untreated patients. Further increasing CSC capabilities may improve overall outcomes, mainly by increasing the use of coiling. Additional studies are necessary to determine the effect of confounders such as aneurysm complexity on outcomes of clipped patients in the modern endovascular era.

[Training and Specialists Qualification System for Neuroendovascular Therapists in Japan].

The specialist qualification system of the Japanese Society for Neuroendovascular Therapy was initiated in 2000. The qualified title is ranked as the technical specialist based on the fundamental clinical societies. After completing the training curriculum mainly programmed in the authorized institutes, the examinees are inspected with a triple-tiered comprehensive style using written, oral, and practical tests. Although the overall passing rate is not very high(50-60%), we are holding more than 1,700 specialists and 400 upper-level specialists designated as trainers and consultants in 2022. According to the definition of the organization of specialist authorization, enough knowledge and experience are required for the specialist to practice the standard treatments and offer adequate patient information. The education and training of the specialists are important duties for upper-level supervisors. In our qualification system, upper-level supervisors are strictly inspected and are requested to have a bigger potential to contribute to the development of the society and to take the lead on academic activity as well as clinical work. All qualified specialists should master "neuroendovascular therapeutics" and always brush up on themselves. In the recent rapid progress of our field, the effort to get the newest information about trends and consensus is essential to achieve the most effective and safest treatments.

Effective treatment of severe stenosis of the carotid and coronary arteries: a case study.

It is considered acceptable to conservatively manage coronary artery bypass grafting patients with carotid artery disease without the need for preoperative corrective carotid revascularization. However, in the present case, rapidly progressive stroke symptoms with penumbra suggested in the arterial spin labeling, carotid artery stenting was performed successfully.

A novel remote hands-on training for neuroendovascular-based treatment in the era of the COVID-19 pandemic.

The COVID-19 pandemic has demanded a change in learning modalities, which led us to develop a remote personal training system for clinicians performing neuroendovascular procedures. A portable vascular model designed for practicing catheter navigation guidance, thrombus retrieval, and intracranial aneurysm coil embolisation was established. We created an environment that enabled interactive dialogue and communication across long distances using the Internet. The instructor conducted approximately 2 h of hands-on training with two to four trainees at a time. Despite the restrictions enforced by the Government of Japan due to the COVID-19 pandemic, 17 online hands-on training were successfully conducted throughout Japan over 1 year for a total of 48 trainees. The developed remote training programme, to avoid the aggregation of a large number of trainees at a developed time, proved to be at par with the conventional learning system. The training was well-received since the operation time was longer and the question and answer sessions were more fulfilling compared to the conventional format in which a group of trainees had got a brief opportunity to receive actual hands-on experience.

A Novel Approach to Neuroendovascular Treatment Looking Up from the Ascending Aorta Using an Alpha Shape Guiding Catheter.

BACKGROUND: A method of guiding an intermediate catheter from a new alpha-type guiding catheter placed in the ascending aorta to the carotid artery is evaluated in neuroendovascular treatment in challenging anatomic directions of the guiding catheter, such as the bovine aortic arch and type III aortic arch. METHODS: The existing 8-Fr guiding catheter was given a strong bending shape at the tip to make it an alpha type. The total length of the catheter was 85 cm. This guiding catheter was inserted into the ascending aorta to verify whether a 6-Fr intermediate or aspiration catheter could be coaxially guided into the right and left internal carotid arteries. A silicone vascular model was used for evaluation and in actual clinical cases. RESULTS: Creating an alpha shape of the catheter at the aortic arch was very easy. The inner catheter could be easily guided from the brachiocephalic artery to the right common carotid artery by pushing the alpha shape guiding catheter toward the aortic valve. The catheter was easily guided into the left common carotid artery when the α-guide was pulled a little bit backward. The 0.071-inch lumen aspiration catheter reached the bilateral middle cerebral arteries. CONCLUSIONS: The 8-Fr alpha shape guiding catheter quickly guides the inner catheter into the bovine and the type III aortic arch by looking up from the ascending aorta.

Mixed Germ Cell Tumor with a Yolk Sac Tumor Component in the Medulla Oblongata of a 50-year-old Patient: A Case Report and Literature Review.

Yolk sac tumor (YST) is a rare primary brain tumor that occurs almost exclusively in patients under 30 years old. Intracranial germ cell tumors are most frequently located in the pineal and suprasellar region. Medulla oblongata YSTs are particularly rare. Extragonadal YSTs may be difficult to diagnose because of their characteristics, such as the rarity and variety of growth patterns. Furthermore, they are known to have a very poor prognosis. We herein report a case of YST of the medulla oblongata in a 50-year-old woman. She was followed up for 18 months without any tumor recurrence.

Positional Relationship between Two Microcatheters according to the Navigation Sequence within the Curved Vessel in Neuroendovascular Procedures.

In neuroendovascular treatment, there are many opportunities to guide multiple catheters into the intracranial blood vessels. We report the relationship between two microcatheters according to the guiding order with experimental in vitro studies. We hypothesize that in a bent blood vessel such as a paraclinoid region of the internal carotid artery, the catheter that was first guided tended to pass through the inside, and the catheter that was guided later tended to pass through the outside. The in vitro verification was performed using a microcatheter and a balloon catheter in a silicone vascular aneurysmal model. As a result, it was found that the two catheters were arranged according to our hypothesis. This finding was also observed during the actual operation of balloon-assisted coil embolization. The positional relationship between the two catheters according to the navigation order is very important, in particular during balloon-assisted coiling and stent-assisted coiling via a jailed microcatheter.

Combined Exoscopic and Endoscopic Two-Step Keyhole Approach for Intracranial Meningiomas.

The advantages of neuroendoscopic surgery are the wide viewing angle and the freedom of an axis of view with minimal surgical trauma. With the advent of the exoscope, which has similar advantages to endoscopy, such as a small body and ergonomically superior heads-up surgery, it has become possible to add a field of view that is similar to that of microsurgery to endoscopic surgery. By taking advantage of the features of these scopes, we report the usefulness of the minimally invasive combined exoscopic and endoscopic two-step keyhole approach (EEKA) for various types of meningiomas. We reviewed data from 34 consecutive cases of EEKA for various types of intracranial meningiomas compared with that of conventional microsurgery. All of the tumors were resected as planned without severe complications. Significantly better outcome data were obtained in terms of the blood loss and the surgical time in the EEKA group, in addition to the craniotomy size. The well-illuminated fine vision in the deep corners by the endoscope enabled radical resection of the tumors with minimum burden on the patients. This technique has the potential for minimally invasive surgery in intracranial meningioma patients, including the older population.

Usefulness of a Curved Multiple Reconstruction Image for Transarterial Intravenous Coil Embolization of a Dural Arteriovenous Fistula of the Sphenobasal Vein: A Case Report.

Hemorrhagic isolated dural arteriovenous fistulas (DAVFs) are often challenging to treat. Here, we report a case of the lateral cavernous sinus (CS) DAVF successfully treated by transarterial intravenous coil embolization using a curved multiplanar reconstruction (MPR) image assistance. A 54-year-old man presented with a severe headache and was diagnosed with subarachnoid hemorrhage caused by CSDAVF. Angiography indicated that the fistula was fed by branches of the left external carotid artery and drained into cortical veins. There were multiple shunting points at the left sphenobasal vein accompanied by varicose veins. Using curved MPR images, the left accessory meningeal artery was chosen for the endovascular approach into the affected veins, including ruptured varix. The shunt was completely occluded by detachable coils. When the curved MPR image indicates a developing feeding artery and a large shunting point, transarterial intravenous coil embolization becomes a good treatment option for CSDAVF, which has no venous access.

Carotid Angioplasty and Stenting for Occlusive Diseases.

Stenting for carotid artery stenosis (CAS) was once denied 15 years ago because it failed to prove the non-inferiority to carotid endarterectomy (CEA). However, it is now reevaluated and is thought better due to higher safety and efficacy thanks to the development of devices, strategies, and various protection methods. To achieve the safe CAS, protection methods and stents should be properly selected based on the vessel course and plaque components on the preoperative plaque images. Particularly multiple protection methods including proximal balloon protection and double-layer micromesh stents are useful for the cases with high-risk and fragile plaque. Perioperative anti-platelet management and the control of blood pressure are also important to avoid the ischemic complications and hyperperfusion. Properly protected and tailored CAS based on the risk management has dramatically improved the clinical results and contributed to extend the indication for more difficult lesions.

Experimental Study of Coil Compaction: Impact of Pulsatile Stress.

Objective: Coil compaction after aneurysm embolization is one of the major issues associated with aneurysm recurrence. On the presumption that pulsatile stress to the aneurysm is responsible for coil compaction, we developed an experimental model in vitro to visualize the mechanical stresses exerted by blood pressure and pulse and their relation to coil compaction. Methods: A closed-type non-circulation system was developed by installing a syringe that generated pressure at one end of a tube, along with a spherical aneurysm made of silicone and a pressure sensor in the bifurcated end. We installed a fixed-pressure model under a steady pressure of 300 mmHg while the pressure-fluctuation model simulated the pressure variations using a plunger (in a syringe) by using a motor that applied pulsatile stress in the range of 50 mmHg for a 10-ms cycle. We devised four types of aneurysms with different depths and the same coil length. After coil packing, the aneurysms were observed for 3 days (the observation period in the pressure-fluctuation model corresponded to approximately 300 days in real time). The distance from the datum point to the observable coil loops was determined as the initial position, and the temporal change in the distance from that position was measured. Results: In the fixed-pressure model, the average distance of coil movement was very small (less than ±0.1 mm). In the pressure-fluctuation model, the movement of coils was observed to be significant for the two longest depths (0.11 and 0.14 mm). The maximal dynamic change in coil movement was observed on the second day. The range of movement was observed to decrease thereafter. Conclusion: Our experimental study enabled the observation of coil movement within a short duration. It examined coil compaction by applying pulsed pressure to the coils at high speeds. Consequently, a shift of the coil loops inside the incompletely occluded aneurysms was detected on applying a pulsed pressure.

A Novel Technique of Microcatheter Shaping using Real Image Display for Endovascular Aneurysmal Coil Embolization.

In coil embolization of intracranial aneurysms, guiding the microcatheter to an appropriate site in the aneurysm and stabilizing it there are important. In paraclinoid internal carotid aneurysms, complicated three-dimensional (3-D) shaping of the microcatheter tip is occasionally required. We devised a novel shaping method for microcatheters by using a real image display (RID). The usefulness of this technique was validated. We used a RID consisting of a couple of concave mirrors. A piece of patient-specific vascular model, which was made using a 3-D printer before the operation, was set inside the RID. We obtained a real 3-D image just above the RID. As a microcatheter and its shaping inner mandrel could be entered in the hologram of the vasculature, we could create the actual shape of the microcatheter. The shaped microcatheter could be navigated at the desired position in the aneurysm. Complete obliteration of the aneurysm was achieved without any trouble among 30 consecutive cases. We evaluated the effectiveness of the RID for making and navigating a microcatheter in cases with challenging anatomies. It was useful for favorable microcatheter shaping, as the RID could be entered inside the aneurysm models, unlike when tracing the outer surface of rigid 3-D models.

Combined Exoscopic and Endoscopic Technique for Craniofacial Resection.

We determined the feasibility of the combined exoscopic-endoscopic technique (CEE) as an alternative to the microscope in craniofacial resection (CFR). This retrospective study was conducted at a single institution and included eight consecutive patients with head and neck tumors who underwent CFR between September 2019 and July 2021. During the transcranial approach, microsurgery was performed using an exoscope in the same manner as in traditional microscopic surgery, and an endoscope was used at the blind spot of the exoscope. The exoscope provided images of sufficient quality to perform microsurgery, while the sphenoid sinus lumen was the blind spot of the exoscope during anterior (n = 3) and anterolateral CFR (n = 2), and the medial aspect of the temporal bone was the blind spot of the exoscope during temporal bone resection (n = 2). These blind spots were visualized by the endoscope to facilitate accurate transection of the skull base. The advantages of the exoscope and endoscope include compact size, ergonomics, surgical field accessibility, and equal visual experience for neurosurgeons and head and neck surgeons, which enabled simultaneous transcranial and transfacial surgical procedures. All the surgeries were successful without any relevant complications. CEE is effective in transcranial skull base surgery, especially CFR involving simultaneous surgical procedures.