Lanzino, Giuseppe

OBJECTIVE De novo aneurysms are rare entities periodically discovered during follow-up imaging. Little is known regarding the frequency with which these lesions form or the time course. This systematic review and meta-analysis was undertaken to estimate the incidence of de novo aneurysms and to determine risk factors for aneurysm formation. METHODS The authors searched multiple databases for studies of patients with unruptured and ruptured aneurysms describing the rate of de novo aneurysm formation. The primary outcome was incidence of de novo aneurysm formation. A meta-analysis was performed using a random-effects model. The authors examined the associations of multiple aneurysms, prior subarachnoid hemorrhage, smoking, sex, age at presentation, and hypertension with de novo aneurysm formation. RESULTS The meta-analysis included 14,968 aneurysm patients who received imaging follow-up from 35 studies. The overall incidence of de novo aneurysm formation was 2% (95% CI 2%–3%) over a mean follow-up time of 8.3 years. The estimated incidence density was 0.3%/patient-year. There was no statistically significant difference in rates of de novo aneurysm formation between patients who had ruptured aneurysms and those with unruptured aneurysms. In 8 studies, 11.2% of de novo aneurysms were found in patients with ≤ 5 years of follow-up and 88.8% were found at > 5 years. The mean time to rupture for de novo aneurysms was 10 years. CONCLUSIONS This systematic review demonstrates that formation of de novo aneurysms is rare. Overall, routine screening for de novo aneurysms is likely to be of low yield and could be performed at time intervals of at least 5 to 10 years.

Incidental vascular lesions are being discovered at an increasing frequency due to widespread noninvasive brain imaging studies. One of these lesions has recently been termed a “pure arterial malformation” (PAM), which is defined as dilated, overlapping, and tortuous arteries forming a mass of arterial loops with a coil-like appearance in the absence of arteriovenous shunting. The pathogenesis of these lesions is not known, but a congenital etiology is suspected. The authors report the case of a 17-year-old female who was found to have a PAM of the posterior inferior cerebellar artery with adipose tissue interspersed within the arterial loops. The authors believe that this abnormal intracranial association between blood vessel and adipose tissue lends further support to the theory that PAMs are the result of a congenital malformation and are therefore safe to manage conservatively given their presumed benign natural history. Far from offering conclusive evidence, this unique case report adds to the growing body of PAM literature and strengthens an increasingly supported congenital theory of genesis.

Purpose:To compare periprocedural complications and in-stent restenosis rates associated with open- vs closed-cell stent designs used in carotid artery stenting (CAS). Methods: A systematic search was conducted to identify all randomized and observational studies published in English up to October 31, 2017, that compared open- vs closed-cell stent designs in CAS. Identified studies were included if they reported the following outcomes: stroke, transient ischemic attack (TIA), myocardial infarction (MI), hemodynamic depression, new ischemic lesions detected on imaging, and death within 30 days, as well as the incidence of in-stent restenosis. A random-effects model meta-analysis was employed. Model results are reported as the odds ratio (OR) and 95% confidence interval (CI). The I 2 statistic was used to assess heterogeneity. Results: Thirty-three studies (2 randomized trials) comprising 20, 291 patients (mean age 71.3±3.0 years; 74.6% men) were included. Patients in the open-cell stent group had a statistically significant lower risk of restenosis ⩾40% (OR 0.42, 95% CI 0.19 to 0.92; I 2 =0%) and ⩾70% (OR 0.23, 95% CI 0.10 to 0.52; I 2 =0%) at a mean follow-up of 24 months. No statistically significant differences were identified for periprocedural stroke, TIA, new ischemic lesions, MI, hemodynamic depression, or death within 30 days after CAS. Sensitivity analysis of the 2 randomized controlled trials only did not point to any significant differences either. Conclusion: Use of open-cell stent design in CAS is associated with a decreased risk for restenosis when compared to the closed-cell stent, without significant differences in periprocedural outcomes.

Abstract Middle cerebral artery (MCA) aneurysms often have an irregular morphology that might require creative clipping techniques even in the case of small aneurysms. In this video, we illustrate the case of a patient with an incidental but very irregular MCA aneurysm. The presence of 2 separate, asymmetric lobes was dealt with by utilizing the “interlocking” clip technique in which a regular clip is used to obliterate 1 portion of the aneurysm and a fenestrated clip, with the ring of the fenestration circling the body of the first clip, is used to obtain obliteration of the other lobe. This patient also had a contralateral internal carotid artery occlusion, and we discuss the pitfalls of temporary clipping in such a situation.

Abstract MicroAVMs (microarteriovenous malformation) are arteriovenous shunts with a nidus smaller than 1 centimeter. 1 They are typically diagnosed after hemorrhage. When the nidus is very small, diagnosis can be challenging even on catheter angiography and careful examination of the arterial and capillary phases is required to identify the early shunt. Because of the very small size, identification and localization of the actual AV shunt can be problematic during surgical exploration. Advances in frameless stereotactic neuronavigation and the introduction of intraoperative indocyanine green (ICG) fluorescein provide useful adjuncts in the surgical treatment of these relatively uncommon lesions. In this video, we present 2 cases which document the value of intraoperative ICG fluorescein as well as some of the surgical pitfalls in the treatment of these lesions.

Abstract Intramedullary epidermoid cysts are extremely rare lesions. Preoperative diagnosis can be challenging due to non-specific imaging futures. We illustrate the case of a 32-year-old man who presented with a symptomatic intramedullary mass, which at surgery proved to be an epidermoid cyst. The spinal cord was decompressed by removing the pearl-white keratin material, although the capsule, which was tenaciously adherent to the surrounding spinal cord parenchyma, was only partially removed. In this video, we illustrate the salient surgical points for the resection of this very unusual intramedullary lesion.

Background and purpose Vertebrobasilar dolichoectatic and fusiform aneurysms (VBDAs) are known to have a poor natural history, with high rates of growth, rupture, and stroke. The purpose of this study was to identify hemodynamic characteristics that differ between VBDAs associated with growth, rupture, and stroke. Materials and methods VBDAs with CT angiography or MR angiography followed longitudinally without treatment were studied. Unstable aneurysms were defined as those that grew or ruptured during follow-up. Aneurysms associated with stroke were defined as those associated with posterior circulation infarct at follow-up. Baseline data, including demographics, comorbidities, and aneurysm morphology and size were collected. Image based computational fluid dynamics models were created and run under pulsatile flow conditions. Relevant hemodynamic and geometric variables were calculated and compared between groups (stable vs unstable and no stroke vs stroke) using the Wilcoxon test. Results A total of 37 VBDAs were included (24 stable, 13 unstable; 30 no stroke, 7 stroke). Unstable aneurysms had lower shear rates (P=0.05), blood flow velocity (P=0.03), and lower vorticity (P=0.049) than stable aneurysms. In addition, unstable aneurysms had higher mean oscillatory shear indices (P=0.001). There were no differences in the hemodynamic characteristics of aneurysms in the stroke group compared with the non-stroke group. Conclusion This small study suggests there may be hemodynamic differences between unstable and stable VBDAs. Unstable VBDAs appear to be under lower flow conditions with lower velocity, vorticity, and shear rates, and have more oscillatory flow. There was no difference in the hemodynamic characteristics of aneurysms in the stroke and no stroke group.