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The influence of aneurysm size on the outcomes of endovascular management (EM) for aneurysmal subarachnoid hemorrhages (aSAH) is poorly understood. To evaluate the outcomes of EM for ruptured large cerebral aneurysms, we retrospectively analyzed the medical records of patients with aSAH that were treated with coiling between 2013 and 2020 and compared the differences in outcomes depending on aneurysm size. A total of 469 patients with aSAH were included; 73 patients had aneurysms measuring 10 mm in diameter (group L), and 396 had aneurysms measuring

The influences of the average degree of polymerization (Dp), which is derived from Mn and terminal end group, on optical and thermal properties of various refractive indexed transparent polymers were investigated. In this study, we selected the alicyclic compound, Dinorbornane dimethanol (DNDM) homo polymer, because it has been used as a representative monomer in low refractive index polymers for its unique properties. DNDM monomer has a stable amorphous phase and reacts like a polymer. Its unique reaction allows continuous investigation from monomer to polymer. For hydroxy end group and phenolic end group polymers, the refractive index (nd) decreased with increasing Dp, and both converged to same value in the high Dp region. However, the Abbe number (νd) of a hydroxy end group polymer is not dependent on Dp, and the νd of a phenolic end group polymer is greatly dependent on Dp. As for glass transition temperatures (Tg), both end group series were increased as Dp increased, and both converged to the same value.

Some methods to identify geometric deviations of five-axis machining centers have been proposed until now. However, they are not suitable for multi-tasking machine tools because of the different configuration and the mutual motion of the axes. Therefore, in this paper, an identification method for multi-tasking machine tools with a swivel tool spindle head in a horizontal position is described. Firstly, geometric deviations are illustrated and the mathematical model considering the squareness of translational axes is established according to the simultaneous three-axis control movements. The influences of mounting errors of the measuring instrument on circular trajectories are investigated and the measurements for the B axis in the Cartesian coordinate system and the measurements for the C axis in a cylindrical coordinate system are proposed. Then, based on the simulation results, formulae are derived from the eccentricities of the circular trajectories. It is found that six measurements are required to identify geometric deviations, which should be performed separately in the B axis X-direction, in B axis Y-direction, in C axis axial direction, and three times in C axis radial direction. Finally, a numerical experiment is conducted and identified results successfully match the geometric deviations. Therefore, the proposed method is proved to identify geometric deviations effectively for multi-tasking machine tools.

The present paper describes the sensitivity coefficient of measurement in the three-dimensional circular interpolation movement that is equivalent to cone-frustum cutting in five-axis machining centers with a tilting rotary table. The sensitive direction of a ball bar having a one-dimensional displacement sensor is parallel to its telescopic bar. In the present paper, the ratio of the measurement value to the actual error is defined as the sensitivity coefficient of measurement. The sensitivity coefficient of each axis is calculated by changing the apex angle and location of the cone-frustum. Different trajectories are obtained according to the attitude of the ball bar. This is due to the resulting variation in the sensitivity coefficient of the ball bar. If the ball bar is set parallel to the base circle of the cone-frustum, and if the center of the cone-frustum is positioned away from the centerline of the rotary table (in the positive direction of the linear axis that is perpendicular to the tilting axis of the table), the trajectory can be obtained appropriately.

Objective: Intraoperative rebleeding during endovascular treatment for ruptured intracranial aneurysms is associated with poor prognosis. Lumbar drainage is performed preoperatively to control intracranial pressure; however, it is associated with a risk of brain herniation or rebleeding because intracranial pressure may change rapidly. Therefore, this study aimed to examine the efficacy and safety of preoperative lumbar drainage. Methods: This retrospective study enrolled 375 patients who underwent endovascular treatment of ruptured intracranial aneurysms at our institution between April 2013 and March 2018. The incidence of rebleeding and clinical outcomes were compared between patients who did and did not undergo preoperative lumbar drainage. Results: Among the 375 patients with ruptured intracranial aneurysms, 324 (86.0%) and 51 (14.0%) patients did and did not undergo lumbar drainage, respectively. The incidence of rebleeding was 11/324 (3.4%) and 2/51 (3.9%) in lumbar drainage and nonlumbar drainage groups, respectively, with no statistical differences (p = 0.98). Of the rebleeding cases, 9/11 (81%) and 2/2 (100%) in lumbar drainage and nonlumbar drainage groups, respectively, were due to intraoperative bleeding, and 2/11 (19%) in the lumbar drainage group, the causes of the rebleeding were undetermined. The incidence of symptomatic vasospasm did not differ significantly between the groups (13.2% vs. 11.8%, P = 0.776), while the incidence of hydrocephalus (24.6% vs. 11.8%, P = 0.043) and meningitis (15.2% vs. 5.9%, P = 0.075) were slightly higher in the lumbar drainage group. Favorable clinical outcomes (modified Rankin Scale score <2) at discharge were less frequent in the lumbar drainage group (55.3% vs. 70.0%, P = 0.051). No significant differences were observed in the propensity score-matched analysis. Conclusion: Lumbar drainage before endovascular treatment for ruptured intracranial aneurysms is a safe procedure that does not increase the incidence of rebleeding. [ABSTRACT FROM AUTHOR]

Background: Neurofibromatosis type 1 (NF-1) is often characterized by vascular disorders related to vessel vulnerability that can lead to unfavorable outcomes. Here, we describe a case of NF-1 complicated with a massive subcutaneous hematoma posing a risk of visual impairment for which rapid decompression and a subsequent less invasive approach result in a favorable outcome. Case Description: A 40-year-old woman with NF-1 presented with a massive left subcutaneous temporal hematoma following a mild head contusion. Four days after hospitalization, the hematoma increased in size and severely compressed the left eye, prompting immediate hematoma removal to preserve visual function. Immediately after the hematoma removal, a superficial temporal arteriovenous fistula was found on the digital subtraction angiography and embolized by the endovascular procedure. Her visual acuity was preserved, and no bleeding recurrence was observed throughout the follow-up. Conclusion: Surgical hematoma removal followed by endovascular treatment was effective in preserving visual function. Since vessel fragility is characteristic of patients with NF-1, it should be kept in mind that vascular complications may lead to serious clinical outcomes. In certain NF-1 cases, less invasive treatments for vascular abnormalities may be preferable. [ABSTRACT FROM AUTHOR]

Importance: Whether intravenous thrombolysis is needed in combination with mechanical thrombectomy in patients with acute large vessel occlusion stroke is unclear.Objective: To examine whether mechanical thrombectomy alone is noninferior to combined intravenous thrombolysis plus mechanical thrombectomy for favorable poststroke outcome.Design, Setting, and Participants: Investigator-initiated, multicenter, randomized, open-label, noninferiority clinical trial in 204 patients with acute ischemic stroke due to large vessel occlusion enrolled at 23 hospital networks in Japan from January 1, 2017, to July 31, 2019, with final follow-up on October 31, 2019.Interventions: Patients were randomly assigned to mechanical thrombectomy alone (n = 101) or combined intravenous thrombolysis (alteplase at a 0.6-mg/kg dose) plus mechanical thrombectomy (n = 103).Main Outcomes and Measures: The primary efficacy end point was a favorable outcome defined as a modified Rankin Scale score (range, 0 [no symptoms] to 6 [death]) of 0 to 2 at 90 days, with a noninferiority margin odds ratio of 0.74, assessed using a 1-sided significance threshold of .025 (97.5% CI). There were 7 prespecified secondary efficacy end points, including mortality by day 90. There were 4 prespecified safety end points, including any intracerebral hemorrhage and symptomatic intracerebral hemorrhage within 36 hours.Results: Among 204 patients (median age, 74 years; 62.7% men; median National Institutes of Health Stroke Scale score, 18), all patients completed the trial. Favorable outcome occurred in 60 patients (59.4%) in the mechanical thrombectomy alone group and 59 patients (57.3%) in the combined intravenous thrombolysis plus mechanical thrombectomy group, with no significant between-group difference (difference, 2.1% [1-sided 97.5% CI, -11.4% to ∞]; odds ratio, 1.09 [1-sided 97.5% CI, 0.63 to ∞]; P = .18 for noninferiority). Among the 7 secondary efficacy end points and 4 safety end points, 10 were not significantly different, including mortality at 90 days (8 [7.9%] vs 9 [8.7%]; difference, -0.8% [95% CI, -9.5% to 7.8%]; odds ratio, 0.90 [95% CI, 0.33 to 2.43]; P > .99). Any intracerebral hemorrhage was observed less frequently in the mechanical thrombectomy alone group than in the combined group (34 [33.7%] vs 52 [50.5%]; difference, -16.8% [95% CI, -32.1% to -1.6%]; odds ratio, 0.50 [95% CI, 0.28 to 0.88]; P = .02). Symptomatic intracerebral hemorrhage was not significantly different between groups (6 [5.9%] vs 8 [7.7%]; difference, -1.8% [95% CI, -9.7% to 6.1%]; odds ratio, 0.75 [95% CI, 0.25 to 2.24]; P = .78).Conclusions and Relevance: Among patients with acute large vessel occlusion stroke, mechanical thrombectomy alone, compared with combined intravenous thrombolysis plus mechanical thrombectomy, failed to demonstrate noninferiority regarding favorable functional outcome. However, the wide confidence intervals around the effect estimate also did not allow a conclusion of inferiority.Trial Registration: umin.ac.jp/ctr Identifier: UMIN000021488. [ABSTRACT FROM AUTHOR]

Background: While recent randomized clinical trials have shown the efficacy of mechanical thrombectomy for acute large vessel anterior cerebral occlusion, cases in patients with a subarachnoid hemorrhage (SAH) were excluded from the study. Case Description: A 58-year-old man presented with a SAH as a result of a ruptured middle cerebral artery aneurysm. Coil embolization was performed, and a right intracranial angiography showed remnants of an aneurysmal neck. However, the following angiography also revealed a thromboembolic complication that occurred in the same territory as the ruptured aneurysm. The patient underwent a rescue mechanical thrombectomy under the working projection. We deployed a retrieval stent without covering the aneurysmal neck. The occluded vessel was recanalized without any hemorrhagic complication. Due to minimal intracerebral infarction, the patient had good outcomes. Conclusion: Mechanical thrombectomy is a useful option to retrieve a clot from an occluded intracranial vessel located near a ruptured aneurysm. Approaching the clot at the working projection is important to ensure safety in the setting of a ruptured aneurysm. [ABSTRACT FROM AUTHOR]

Purpose To evaluate the clinical outcome and MRI findings after carotid artery stenting (CAS) without post-dilatation. Methods Between May 2005 and April 2012, a total of 169 consecutive patients (61.4% symptomatic) underwent 176 CAS procedures performed with an embolic protection device (GuardWire, n=116; FilterWire EZ, n=60). All stents were deployed without post-dilatation. Periprocedural complications and mid- term outcomes were analyzed. Results The stroke rate was 2.3% within 30 days post-CAS (asymptomatic patients 1.5%; symptomatic patients 2.8%). Cerebral infarction occurred in one asymptomatic patient (1.5%) and one symptomatic patient (0.9%). Intracranial hemorrhage occurred in two symptomatic patients (1.9%). Post-CAS diffusion- weighted imaging (DWI) revealed a high-intensity area in 26 of 176 procedures (14.8%). Ipsilateral stroke after 31 days occurred in two patients (1.1%) and restenosis occurred in six (3.4%). A post-CAS comparison of the embolic protection devices revealed no difference in stroke incidence within 30 days and in DWI high-intensity area. Conclusions Our CAS procedure without post-dilatation is feasible, safe and associated with a low incidence of stroke and restenosis. [ABSTRACT FROM AUTHOR]

Spontaneous and isolated dissecting aneurysm of the superior mesenteric artery is a rare event that has been successfully treated by surgery in several reported cases. To our knowledge, we present the first case of a patient with spontaneous and isolated dissecting aneurysm of the superior mesenteric artery that was successfully treated by endovascular stent-graft placement. [ABSTRACT FROM AUTHOR]