Contour-Assisted coiling with jailed microcatheter May result in better occlusion (CoCoJaMBO) in wide-necked intracranial aneurysms: Proof of principle and immediate angiographic results

Purpose Wide-necked bifurcation aneurysms, partially thrombosed, and recurrences of large and giant aneurysms are challenging to treat. We report our preliminary experience with a Contour-assisted coiling technique and discuss the periprocedural safety, feasibility, and effectiveness of the approach. Methods We retrospectively reviewed consecutive patients who received endovascular treatment for intracranial aneurysms with an intra-aneurysmal flow disruptor (Contour) at two neurovascular centres between October 2018 and December 2020 and identified patients treated with a combination of Contour and platinum coils. Clinical and procedural data were recorded. Results For this analysis, 8 patients (5 female) aged 60.1 ± 9.2 years on average were identified. Three of 8 aneurysms were associated with previous acute subarachnoid hemorrhage (SAH). The mean average dome height was 12.8 ± 7.6 mm, mean maximum dome width 10.3 ± 5.4 mm, and neck width 5.5 ± 2.5 mm. The mean dome-to-neck ratio was 1.9 ± 1.0. Immediate complete occlusion of the aneurysm was seen in 5 of 8 cases. In one SAH patient, a parent vessel was temporarily occluded but could be reopened rapidly. One device detached prematurely without any sequelae. No other procedural adverse events were recorded. Conclusion From this initial experience, Contour with adjunctive coiling is a safe and technically feasible method for endovascular treatment of large, wide-necked, partially thrombosed, recurrent, or ruptured bifurcation aneurysms. Further studies with larger numbers of patients and longer follow-up are needed to confirm our results.

Mechanical and Formability Evaluation of ST14 Alloys Welded by Friction Stir Welding

Friction stir welding as one of the modern methods of solid-state welding of steel sheets and aluminum is a highly regarded industry. In these studies, the experimental design and response surface methodology were used. Optimization of experimental conditions and results which are compared with good agreement between the results was observed. The mechanical properties and ductility of welded plates under optimal conditions were studied. Microhardness testing, metallography, tensile testing, and limiting dome height were used to investigate the mechanical properties and formability limit diagram attached, respectively. The results showed that the heat-affected zone is very small and narrow and not easily distinguished from the base metal. In all tests, the failure of the dome height limit in the area was chaos. In all samples welded with the optimal parameters, tensile failure occurred in the base metal region. Turbulence in the region confirms the presence of WC particles. Experimental design and response surface methodology could introduce an optimal state, and the creation of common defects in the FSW process can prevent the binding strength of the guarantee. But due to the lack of proper stirring in the perturbation area in the samples welded with non-optimized parameters, the strength of the connection is not suitable, and samples were broken from the SZ region.

Effect of Biomimetic Surface Geometry, Soil Texture, and Soil Moisture Content on the Drag Force of Soil-Touching Parts

Soil adhesion is a major problem for agricultural machinery, especially in sticky soils within the plastic range. One promising and practical way to minimize soil–tool adhesion is to modify the surface geometry to one inspired by soil-burrowing animals. In this study, 27 domed discs were fabricated according to an L27 (33) Taguchi orthogonal array and tested to determine the optimal dimensions of domed surfaces to reduce drag force. The optimized domed disc was tested in a soil bin under different soil conditions (soil texture: silty loam and sandy clay loam; soil moisture content: 23%, 30%, and 37%). All trials included a flat disc (without a dome pattern) as a control. The optimal dimensions of domed surfaces to generate the lowest possible drag force under the present experimental conditions were explored based on signal-to-noise ratio analysis. The optimal levels of control parameters were found at a surface coverage ratio of 60%, dome height of 5 mm, and dome base diameter of 20 mm. Statistics revealed that the dome height-to-diameter ratio and disc coverage ratio are crucial factors that influence the drag force of domed surfaces. In contrast, the dome base diameter had a limited influence on drag force. In all treatments, the drag force of the optimized domed disc was less than that of the flat disc (by about 9% to 25%, according to soil conditions). Accordingly, it can be concluded that adequately designed domed surfaces could significantly reduce the drag force in sticky soil compared to their flat counterparts.

Early clinical experience with the p48MW HPC and p64MW HPC flow diverters in the anterior circulation aneurysm using single anti-platelet treatment

Background The p64MW HPC and p48MW HPC flow diverters have reduced thrombogenicity due to hydrophilic coating. The purpose of this study was to evaluate its safety and efficacy in Mongolian patients under single antiplatelet therapy (SAPT) with prasugrel. Materials and methods We performed a retrospective review of patients enrolled into our prospectively maintained database to identify all patients treated with either the p48MW HPC or p64MW HPC under SAPT. We recorded baseline demographics, aneurysm size and location, procedural complications, angiographic and clinical results. Results 24 patients, (female = 21, 87.5%), age 48.2 ± 11.6 years (range 25–63) underwent treatment of 30 aneurysms with either p64MW HPC or p48MW HPC. All aneurysms were saccular with dome width 8.2 ± 6.5 (range 1.6–26.0 mm) and dome height 7.6 ± 6.7 (range 1.6–30.0 mm). None of the aneurysms were previously treated. The average PRU was 54.6 ± 31.2 (range 1–127) on pre-operative VerifyNow testing. Angiographic follow-up was available for 13 patients (17 aneurysms), 183 ± 36 days post-procedure, at which point 64.7% of aneurysms (n = 11/17) were completely occluded and 11.8% (n = 2/17) had only neck remnants resulting in 76.5% of aneurysms being adequately occluded A single intra-operative complication (4.2%) occurred however all patients were mRS ≤1 at last follow-up. There were two post-operative complications neither of which resulted in permanent neurological morbidity. There were no instances of post-operative aneurysmal rupture or delayed parenchymal haemorrhage. The overall mortality was 0%. Conclusion The efficacy and safety of p64MW HPC coated devices under SAPT is similar to uncoated flow diverters that require DAPT.

Application of a rabbit-elastase aneurysm model for preliminary histology assessment of the PPODA-QT liquid embolic

Background: PPODA-QT is a novel liquid embolic under development for the treatment of cerebral aneurysms. We sought to test the rabbit-elastase aneurysm model to evaluate the tissue response following PPODA-QT embolization. Methods: Experimental elastase-induced aneurysms were created in fourteen New Zealand White Rabbits. Eight animals were used for aneurysm model and endovascular embolization technique development. Six PPODA-QT-treated animals were enrolled in the study. Control and aneurysm tissues were harvested at acute (n = 2), 1-month (n = 2), and 3-month (n = 2) timepoints and the tissues were prepared for histology assessment. Results: All fourteen rabbit-elastase aneurysms resulted in small and medium aneurysm heights (<10 mm dome height) with highly variable neck morphologies, small midline dome diameters, and beyond-wide dome-to-neck (d: n) ratios. Histological evaluation of four aneurysms, treated with PPODA-QT, demonstrated reorganization of aneurysm wall elastin into a smooth muscle layer, and observed as early as the 1-month survival timepoint. At the aneurysm neck, a homogenous neointimal layer (200–300 μm) formed at the PPODA-QT interface, sealing off the parent vessel from the aneurysm dome. No adverse immune response was evident at 1- and 3-month survival timepoints. Conclusion: PPODA-QT successfully embolized the treated aneurysms. Following PPODA-QT embolization, neointimal tissue growth and remodeling were noted with minimal immunological response. The experimental aneurysms created in rabbits were uniformly small with inconsistent neck morphology. Further testing of PPODA-QT will be conducted in larger aneurysm models for device delivery optimization and aneurysm healing assessment before human clinical investigation.

Endovascular Treatment of Intracranial Aneurysms Using the Novel Low Profile Visualized Intraluminal Support EVO Stent: Multicenter Early Feasibility Experience

Purpose: Low-profile, self-expandable stents have broadened therapeutic options available for definitive treatment of intracranial aneurysms. The novel Low-Profile Visualized Intraluminal Support (LVIS) EVO stent extends upon the success of its predecessor, the LVIS Jr stent, aiming to enable higher visibility and greater opening ability within a self-expandable and fully retrievable microstent system. In this study, we aim to report the early safety and feasibility experience with the LVIS EVO stent.Materials and Methods: A multicenter, retrospective, observational study was conducted on patients who had intracranial aneurysms treated with the LVIS EVO stent across 3 Australian neurovascular centers between February 2020 and September 2020. Short-term technical and clinical outcomes were evaluated.Results: A total of 22 LVIS EVO stents were successfully implanted to treat 15 aneurysms (3 ruptured, 12 unruptured) in 15 patients. Aneurysms ranged from 2 mm to 35 mm in dome height. The LVIS EVO stent was used for stent-assisted coiling in 11 patients and flow diversion in 4 patients. There were no device-related procedural complications. There were 2 cases of peri-procedural symptomatic thromboembolic complications and no procedure-related mortality. At early radiological follow up, 10 patients had complete occlusion, 4 patients had small neck remnants, and 1 patient who was managed with flow diversion had a residual aneurysm.Conclusion: Early experience with the LVIS EVO stent demonstrated safety and feasibility for stent-assisted coiling as well as flow diversion for intracranial aneurysms. In this heterogeneous cohort, including ruptured, complex, and large aneurysms, all cases were technically successful.

Normal Diaphragm Measurements in the Saudi Population Using Posteroanterior Chest Radiograph

The aim of this study was to establish normal measurements of the hemidiaphragm widths and heights in the Saudi population by a posteroanterior (PA) chest X-ray in the Mecca Region. Methods and Results: The data were collected prospectively at King Abdulaziz Hospital in Saudi Arabia, Jeddah, between March and April 2021, using a computed radiography imaging unit. A total of 45 patients (51.1% men and 48.9% women; the age range between 15 and 79 years) were included in the study. Measurements were obtained on an ideal PA chest radiograph by measuring the distance from the highest points of the right hemidiaphragm and left hemidiaphragm. The width from the right and left costophrenic angle was also measured as an ended point. The total diaphragm width (DW) was 278.32±24.83mm, the total right diaphragmatic dome height (RDDH) -51.30±10.58mm, and left diaphragmatic dome height (LDDH) - 38.40±9.21mm. The DW was greater in men than in women: 291.74±20.4mm and 264.28±21.2mm, respectively. RDDH and LDDH were also greater in men than in women: 55.4±6.77mm and 47.005±12.19mm, and 43.29±6.65mm and 33.28±8.83, respectively Conclusion: Computed radiography was useful in measuring the diaphragm because measurement points can be identified accurately and easily due to the availability of the processing system functions such as the ability to manipulate the image resolution, image contrast, and magnification.

A study of buckling phenomenon in dielectric elastomeric actuator with different potential energy functions

The present study deals with the buckling phenomenon modeling in a dome-shaped dielectric elastomeric (DE) actuator used in different aerodynamic and fluid power system applications. The DE actuator is a circular membrane type of actuator, which shows a large out-of-plane axial-symmetric deformation with an electrically induced loading condition. A classical continuum mechanics-based analytical model is developed to predict the electrically induced buckling deformation in the actuator. A detailed parametric study has been performed to see the influence of standard Neo-Hookean and Mooney-Rivlin types of potential energies on the geometrical and physical parameters. The findings show that the present model successfully links the sensitivity of different potential energies concerning the actuator’s initial dome height and radius.

Investigation of the Thickness Differential on the Formability of Aluminum Tailor Welded Blanks

A finite element model is proposed to investigate the effect of thickness differential on Limiting Dome Height (LDH) testing of aluminum tailor-welded blanks. The numerical model is validated via comparison of the equivalent plastic strain and displacement distribution between the simulation results and the experimental data. The normalized equivalent plastic strain and normalized LDH values are proposed as a means of quantifying the influence of thickness differential for a variety of different ratios. Increasing thickness differential was found to decrease the normalized equivalent plastic strain and normalized LDH values, this providing an evaluation of blank formability.