Endovascular therapy versus microsurgical clipping of unruptured wide-neck aneurysms: a prospective multicenter study with propensity score analysis

OBJECTIVE Numerous techniques have been developed to treat wide-neck aneurysms (WNAs), each with different safety and efficacy profiles. Few studies have compared endovascular therapy (EVT) with microsurgery (MS). The authors’ objective was to perform a prospective multicenter study of a WNA registry using rigorous outcome assessments and to compare EVT and MS using propensity score analysis (PSA). METHODS Unruptured, saccular, not previously treated WNAs were included. WNA was defined as an aneurysm with a neck width ≥ 4 mm or a dome-to-neck ratio (DTNR) < 2. The primary outcome was modified Rankin Scale (mRS) score at 1 year after treatment (good outcome was defined as mRS score 0–2), as assessed by blinded research nurses and compared with PSA. Angiographic outcome was assessed using the Raymond scale with core laboratory review (adequate occlusion was defined as Raymond scale score 1–2). RESULTS The analysis included 224 unruptured aneurysms in the EVT cohort (n = 140) and MS cohort (n = 84). There were no differences in baseline demographic characteristics, such as proportion of patients with good baseline mRS score (94.3% of the EVT cohort vs 94.0% of the MS cohort, p = 0.941). WNA inclusion criteria were similar between cohorts, with the most common being both neck width ≥ 4 mm and DTNR < 2 (50.7% of the EVT cohort vs 50.0% of the MS cohort, p = 0.228). More paraclinoid (32.1% vs 9.5%) and basilar tip (7.1% vs 3.6%) aneurysms were treated with EVT, whereas more middle cerebral artery (13.6% vs 42.9%) and pericallosal (1.4% vs 4.8%) aneurysms were treated with MS (p < 0.001). EVT aneurysms were slightly larger (p = 0.040), and MS aneurysms had a slightly lower mean DTNR (1.4 for the EVT cohort vs 1.3 for the MS cohort, p = 0.010). Within the EVT cohort, 9.3% of patients underwent stand-alone coiling, 17.1% balloon-assisted coiling, 34.3% stent-assisted coiling, 37.1% flow diversion, and 2.1% PulseRider-assisted coiling. Neurological morbidity secondary to a procedural complication was more common in the MS cohort (10.3% vs 1.4%, p = 0.003). One-year mRS scores were assessed for 218 patients (97.3%), and no significantly increased risk of poor clinical outcome was found for the MS cohort (OR 2.17, 95% CI 0.84–5.60, p = 0.110). In an unadjusted direct comparison, more patients in the EVT cohort achieved a good clinical outcome at 1 year (93.4% vs 84.1%, p = 0.048). Final adequate angiographic outcome was superior in the MS cohort (97.6% of the MS cohort vs 86.5% of the EVT cohort, p = 0.007). CONCLUSIONS Although the treatments for unruptured WNA had similar clinical outcomes according to PSA, there were fewer complications and superior clinical outcome in the EVT cohort and superior angiographic outcomes in the MS cohort according to the unadjusted analysis. These results may be considered when selecting treatment modalities for patients with unruptured WNAs.

Abstract 1122‐000115: Coiling of Wide‐Necked Ruptured Aneurysms: A Subset Analysis of the SMART Registry

Introduction : The purpose of this study was to assess the 1‐year clinical outcomes of wide‐necked ruptured aneurysms treated with coiling. Methods : Data on patients with a wide‐necked ruptured aneurysm were extracted from a prospective multicenter registry (SMART) that enrolled patients with intracranial aneurysm or other neurovascular abnormality who underwent coiling. A wide neck was defined as a neck width of at least 4 mm or as a dome‐to‐neck ratio (largest diameter / neck width) of less than 2. Enrollment was not limited by Hunt and Hess grade. The primary safety outcome was device‐related serious adverse events within 24 hours, and the primary effectiveness outcome was retreatment through follow‐up. Results : Of the 995 adults enrolled in the SMART registry, 144 had a wide‐necked ruptured aneurysm (Table). Average patient age was 59.3 years (SD 14.3), and 74.3% were female. Lesion locations were internal carotid artery, 31.3%; anterior communicating artery, 31.9%; middle communicating artery, 10.4%; and posterior circulation, 26.4%. Aneurysm sizes were small, 27.1%; medium, 54.2%; large, 18.1%; and giant, 0.7%. The most common aneurysm type was saccular (88.8%, 127/143). Coiling was stent assisted in 10.4% of patients and balloon assisted in 36.1% of patients. The rate of device‐related serious adverse events within 24 hours was 3.5%. The rate of retreatment through follow‐up was 20.6% (20/97). At 1 year, 82.6% (76/92) of patients had a Raymond–Roy Occlusion Classification of I or II, 32.6% (30/92) had progressive occlusion, and 46.7% (43/92) had stable occlusion. The 1‐year all‐cause mortality rate was 12.5%. At 1‐year follow‐up, 58.3% (42/72) of patients had a modified Rankin Scale score of 0 to 2. Conclusions : Treatment of wide‐necked ruptured aneurysms with coiling has acceptable occlusion and retreatment rates at 1‐year follow‐up.

Regularities of Electrical Conductivity of Monolayer Graphene Nanomesh with Round Holes

This paper studies graphene nanomesh with different neck width is the smallest distance between two neighboring holes. The electrical properties of graphene nanomesh with circular holes were calculated in dependence on its neck width. For the considered structures energetical characteristics including energy gap (Egap), Fermi level (Ef), and density of electron states (DOS) were found. It was established that graphene nanomesh demonstrated both metallic and semiconductor types of conductivity when the neck width was increased along the zigzag direction. In the case of increasing the neck width along armchair direction, graphene nanomesh demonstrated only a metallic type of conductivity. It was observed the anisotropy of electrical conductivity depending on the direction along which the current transfer was carried out.

Aspect ratio is associated with recanalization after coiling of unruptured intracranial aneurysms

Background The rate of recanalization after coil embolization for unruptured intracranial aneurysms (UIAs) is reported to occur around 11.3-49%. Aim of this study is to investigated the factors that influence the recanalization after coil embolization for unruptured intracranial aneurysms (UIAs) in our institution. Methods We retrospectively investigated 307 UIAs in 296 patients treated at our institution between April 2004 and December 2016. The stent used cases were excluded. Cerebral angiography and 3D TOF MRA were used for evaluation of the postoperative occlusion status. Volume embolization ratio (VER), aneurysmal size, neck width, and aspect ratio (AR) were compared between the recanalized and non-recanalized groups. Results The mean follow-up period ranged from 6 to 172 months (mean: 79.0±39.8 months). Recanalization was noted in 87 (28.3%) aneurysms, and 19 (6.2%) aneurysms required retreatment. There was no aneurysmal rupture during the follow-up period. Univariate analysis showed that the aneurysm size (p < 0.001), neck width (p = 0.002), AR (p = 0.003), and VER (p = 0.027) were associated with recanalization. Multivariate logistic regression analysis showed that the AR (p =0.004) and VER (p =0.015) were significant predictors of recanalization. Conclusions In our study, AR and VER were significant predictors of recanalization after coil embolization for UIAs.

CVD-Grown Monolayer Graphene-Based Geometric Diode for THz Rectennas

For THz rectennas, ultra-fast diodes are required. While the metal–insulator–metal (MIM) diode has been investigated in recent years, it suffers from large resistance and capacitance, as well as a low cut-off frequency. Alternatively, a geometric diode can be used, which is more suitable due to its planar structure. However, there is only one report of a THz geometric diode based on a monolayer graphene. It is based on exfoliated graphene, and thus, it is not suitable for mass production. In this work, we demonstrate chemical vapor deposition (CVD)-grown monolayer graphene based geometric diodes, which are mass-producible. The diode’s performance has been studied experimentally by varying the neck widths from 250–50 nm, the latter being the smallest reported neck width for a graphene geometric diode. It was observed that by decreasing the neck widths, the diode parameters such as asymmetry, nonlinearity, zero-bias resistance, and responsivity increased within the range studied. For the 50 nm neck width diode, the asymmetry ratio was 1.40 for an applied voltage ranging from −2 V to 2 V, and the zero-bias responsivity was 0.0628 A/W. The performance of the diode was also verified through particle-in-cell Monte Carlo simulations, which showed that the simulated current-voltage characteristics were consistent with our experimental results.

Endovascular treatment of complex bifurcation aneurysms using the pConus device: clinical cases

The objective is to present the clinical experience of using the pConus stent-like device in the treatment of complex bifurcation aneurysms.Clinical cases. A 64-year-old patient was admitted with complaints of periodic headache without loss of consciousness and an increase in focal symptoms. Saccular aneurysms of the anterior communicating artery and the left superior cerebellar artery were found without signs of subarachnoid hemorrhage. For occlusion of the aneurysm of the left superior cerebellar artery (dimensions 7.4 х 5.3 mm, neck width 5.0 mm, facing left and up, body/neck ratio 1.48, the branch of the artery branched off from the neck), a pConus device (crown diameter 8 mm) was used with micro-coils.A 61-year-old patient was admitted with complaints of headache in the occipital region, accompanied by repeated vomiting and an increase in blood pressure to 200/110 mm Hg. Subarachnoid hemorrhage and a saccular aneurysm of the basilar artery bifurcation (facing up, anteriorly and somewhat to the left, measuring 4.9 x 3.4 mm, neck width 3.1 mm, dome/neck ratio 1.1) were revealed. A pConus device was used for micro-coils occlusion (4-25-6 mm).In the postoperative period, both patients did not experience an increase in focal neurological symptoms. Control angiography after 6 months confirmed stable occlusion, all major vessels were passable.Conclusion. In the described cases, there were no technical problems during the installation and implantation of the device. The use of the pConus device in the treatment of complex bifurcation aneurysms technically simplifies surgical intervention, since it does not require catheterization of the efferent vessels of the aneurysm.

Holey Graphene: Topological Control of Electronic Properties and Electric Conductivity

This paper studies holey graphene with various neck widths (the smallest distance between two neighbor holes). For the considered structures, the energy gap, the Fermi level, the density of electronic states, and the distribution of the local density of electronic states (LDOS) were found. The electroconductive properties of holey graphene with round holes were calculated depending on the neck width. It was found that, depending on the neck width, holey graphene demonstrated a semiconductor type of conductivity with an energy gap varying in the range of 0.01–0.37 eV. It was also shown that by changing the neck width, it is possible to control the electrical conductivity of holey graphene. The anisotropy of holey graphene electrical conductivity was observed depending on the direction of the current transfer.

Femoral Neck Width Predict Low Bone Mass in Patients with Multiple Hereditary Exostoses

Background: Recent report revealed multiple hereditary exostoses (MHE) patients showed the osteoporosis. This study aimed to determine if proximal femur deformities can indicate low bone mass in MHE patients and to investigate the correlation between Z-score or T-score and hip geometry parameters. Patients and Methods: Twenty MHE patients from unrelated families were included in this study. Bone mineral density (BMD) of both femoral neck (n = 40) was examined using dual-energy x-ray absorptiometry. We examined femoral neck axis length (FNAL), femoral head diameter (FHD), femoral neck width (FNW), femoral shaft width (FSW), and femoral neck angle (FNA) and calculated the femoral head-neck ratio (FHNR=FHD/FNW). We examined the correlation between these parameters and Z-score or T-score using linear regression analysis followed by Spearman rank correlation coefficient.Results: Of the patients, 91.7% (22 of 24) male and 100% (16 of 16) female had a Z-score <0 in the femoral neck area. Results also showed that the femoral neck area of 62.5% (15 of 24) male and 56.3% (9 of 16) female patients are within the range for osteopenia. The femoral neck are of seven patients (17.5%) were found to be within the range for osteoporosis. These results suggest that MHE patients tend to have low bone mass. We found a significant correlation between FNW and Z-score (r = -0.3924, P = 0.0123), but there was no significant difference between Z-score and FNAL, FHD, FSW, NSA, and FHNR. We also found that there were significant differences between T-score and FNW and T-score and FHNR (r = -0.4787, P = 0.0018 and r = 0.3636, P = 0.0211, respectively). There was no significant difference between T-score and the other parameters.Conclusions: We found that the femoral neck width significantly correlates with Z-score or T-score. These results suggest that the femoral neck width may be a reliable predicting factor of bone mineral density.

Morphometric Parameters of the Proximal Femur in Nepalese Population: A Cross-sectional Study

Background: Most of the proximal femur fractures are managed surgically by internal fiation with a variety of implants. Improperly designed or ill-fited implant may lead to a failure of fiation, breakage of implant and nonunion, thus increasing the morbidity and the cost of treatment. This study was conducted to evaluate the radiographic morphometry of the proximal femur which may be helpful in designing the implants for the Nepalese population. Methods: In this cross-sectional study, 84 patients aged 18 years and above with traumatic unilateral hip fracture were enrolled. Anthropometric measurements were recorded. The postoperative check X-ray in the antero-posterior view of the pelvis and bilateral hip were assessed. Various morphometric parameters of the proximal femur were measured and recorded in the radiograph of the unaffcted limb using a digital caliper. Results: Out of 84 patients, 47 were male. The mean ± SD femoral neck width, femoral neck length, femoral axis length, cervico-diaphyseal angle, acetabular tear-drop distance, and great trochanter-pubic symphysis distance were 36.10 ± 5.67 mm, 28.29 ± 4.18 mm, 104.51 ± 9.56 mm, 130.35 ± 8.67°, 32.56 ± 11.05 mm, and 163.07 ± 10.71 mm respectively. The femoral neck width was found to be signifiantly larger in males (39.08 ± 3.06 mm) than in females (32.32 ± 5.99 mm, p < 0.001). Conclusion: This study determined the radiographic measurement of the proximal femur and found that the femoral neck width of the males was larger than that of the females.

Ultrastructural comparison of dendritic spine morphology preserved with cryo and chemical fixation

Previously, we showed that cryo fixation of adult mouse brain tissue gave a truer representation of brain ultrastructure in comparison with a standard chemical fixation method (Korogod et al., 2015). Extracellular space matched physiological measurements, there were larger numbers of docked vesicles and less glial coverage of synapses and blood capillaries. Here, using the same preservation approaches, we compared the morphology of dendritic spines. We show that the length of the spine and the volume of its head is unchanged; however, the spine neck width is thinner by more than 30% after cryo fixation. In addition, the weak correlation between spine neck width and head volume seen after chemical fixation was not present in cryo-fixed spines. Our data suggest that spine neck geometry is independent of the spine head volume, with cryo fixation showing enhanced spine head compartmentalization and a higher predicted electrical resistance between spine head and parent dendrite.