Basilar Apex Aneurysms in the Setting of Carotid Artery Stenosis: Case Series and Angiographic Anatomic Study.

BACKGROUND: Intracranial aneurysms (IAs) are life-threatening lesions known within the literature to be found incidentally during routine angiographic workup for carotid artery stenosis (CAS). As IAs are associated with vascular shear stress, it is reasonable to expect that altered flow demands within the anterior circulation, such as with CAS, increase compensatory flow demands via the Circle of Willis (COW) and may induce similar stress at the basilar apex. OBJECTIVE: We present a series of nine unruptured basilar apex aneurysms (BAA) with CAS and a comparative radiographic analysis to BAA without CAS. METHODS: Twenty-three patients with BAA were retrospectively identified using records from 2011 to 2016. CAS by North American Symptomatic Carotid Endarterectomy Trial (NASCET) criteria, morphology of BAA, competency of COW, and anatomic relationships within the posterior circulation were examined independently by a neuroradiologist using angiographic imaging. RESULTS: Nine (39%) of the twenty-three BAA patients had CAS, with six having stenosis ≥50%. Four (67%) of the patients with ≥50% CAS demonstrated aneurysm flow angles contralateral to the side with highest CAS. Additionally, the angle between the basilar artery (BA) trajectory and aneurysm neck was observed to be smaller in patients with ≥50% CAS (61 vs 74 degrees). No significant differences in COW patency, posterior circulation morphology, and degree of stenosis were observed. CONCLUSION: Changes in the cervical carotid arteries may lead to blood flow alterations in the posterior circulation that increase the propensity for BAA formation. Posterior circulation imaging can be considered in CAS patients to screen for BAA.

Morphologic variations of the second cervical vertebra in Down syndrome compared with age-matched peers.

OBJECTIVEAtlantoaxial instability is an important cause of pain and neurological dysfunction in patients with Down syndrome (DS), frequently requiring instrumented fusion of the upper cervical spine. This study provides a quantitative analysis of C2 morphology in DS patients compared with their peers without DS to identify differences that must be considered for the safe placement of instrumentation.METHODSA retrospective chart review identified age-matched patients with and without DS with a CT scan of the cervical spine. Three-dimensional reconstructions of these scans were made with images along the axis of, and perpendicular to, the pars, lamina, facet, and transverse foramen of C2 bilaterally. Two of the authors performed independent measurements of anatomical structures using these images, and the average of the 2 raters' measurements was recorded. Pedicle height and width; pars axis length (the distance from the facet to the anterior vertebral body through the pars); pars rostrocaudal angle (angle of the pars axis length to the endplate of C2); pars axial angle (angle of the pars axis length to the median coronal plane); lamina height, length, and width; lamina angle (angle of the lamina length to the median coronal plane); and transverse foramen posterior distance (the distance from the posterior wall of the transverse foramen to the tangent of the posterior vertebral body) were measured bilaterally. Patients with and without DS were compared using a mixed-effects model accounting for patient height.RESULTSA total of 18 patients with and 20 patients without DS were included in the analysis. The groups were matched based on age and sex. The median height was 147 cm (IQR 142-160 cm) in the DS group and 165 cm (IQR 161-172 cm) in the non-DS group (p < 0.001). After accounting for variations in height, the mean pars rostrocaudal angle was greater (50.86° vs 45.54°, p = 0.004), the mean transverse foramen posterior distance was less (-1.5 mm vs +1.3 mm, p = 0.001), and the mean lamina width was less (6.2 mm vs 7.7 mm, p = 0.038) in patients with DS.CONCLUSIONSPatients with DS had a steeper rostrocaudal trajectory of the pars, a more posteriorly positioned transverse foramen posterior wall, and a narrower lamina compared with age- and sex-matched peers. These variations should be considered during surgical planning, as they may have implications to safe placement of instrumentation.

Balloon-Occlusion Catheter Onyx Embolization of a Spinal Dural Arteriovenous Fistula Presenting with Subarachnoid Hemorrhage in a Pediatric Patient.

OBJECTIVE: Spinal dural arteriovenous fistulas (DAVFs) are insidious pathologies that, if left untreated, harbor potentially devastating consequences to the central nervous system. Spinal DAVFs are rare in the adult population and exceedingly uncommon in the pediatric population. In this report, we describe a spinal DAVF in a 3-year-old child whose initial presentation is subarachnoid hemorrhage (SAH). Balloon-test occlusion and balloon-catheter-assisted embolization of DAVF have not been previously described, and their advantages over alternative embolic and surgical techniques are discussed. METHODS: We performed a literature search on MEDLINE/PubMed to review current reports describing the epidemiology, clinical presentation, and treatment of spinal DAVFs. In this report, we describe a spinal DAVF in a 3-year-old child whose initial presentation is SAH. RESULTS: A spinal DAVF was diagnosed after deciding to image not only the brain but also the spine. Using a balloon-occlusion catheter, we confirmed that the DAVF arterial feeding vessel could be safely embolized. We then proceeded to effectively treat the DAVF with balloon-catheter-assisted Onyx-18 embolization. CONCLUSION: Based on our report and an analysis of the literature, we propose that pediatric patients presenting with nontraumatic SAH should undergo at least a magnetic resonance imaging of the brain and cervical spine as part of their initial workup. In addition, we describe a balloon-occlusion catheter embolization technique that allows not only excellent embolic penetration of the fistula but also prevention of microcatheter reflux and lessening of the need for a tedious plug-and-stack technique.

Complications of neuroimaging.

Modern imaging techniques with computed tomography (CT) and magnetic resonance imaging (MRI) have revolutionized neuroimaging. While eliminating the risks of invasive procedures, new risks must now be considered before ordering neuroimaging. Advanced imaging techniques with CT may pose a risk of significant radiation exposure. Contrast may pose a risk in patients with pre-existing renal failure. MR is associated with risks related to the static magnetic field, to risks associated with the magnetic field gradients, and to risk from contrast media. Neurointervenional techniques allow for nonoperative treatment of a variety of intracranial and spinal pathologies, but with associated risks of embolization, radiation exposure, bleeding complications at the access site and a potential for contrast-related nephropathy.

Balloon dilatation of biliary-enteric strictures in children.

OBJECTIVE: The objective of our study was to evaluate the efficacy and safety of balloon dilatation in the treatment of anastomotic strictures in children with liver transplants. MATERIALS AND METHODS: For a period of 7 years, we treated 20 consecutive biliary-enteric strictures in 19 children (age range, 13 months to 17.9 years, mean, 7.3 years) with balloon dilatation. Dilatation was performed between 30 days and 8.4 years (mean, 2.6 years) following surgical creation of the biliary-enteric anastomosis. Thirteen patients had left lateral segment liver transplant grafts, one patient had a split-liver, left-lobe graft, and five patients had whole liver grafts. RESULTS: Technical success was 100% and there were no procedure-related complications. One patient with a patent anastomosis underwent repeat transplantation 183 days after the procedure for chronic rejection. In 58% (11/19) of the remaining procedures, balloon dilatation resulted in biliary-enteric patency at one year, and continued patency ranges from 1.4 to 5.4 years (mean, 3.6 years). In 40% (8/20) of the procedures, the biliary-enteric stricture persisted after balloon dilatation, and these patients eventually underwent surgical revision, retransplantation, or endobiliary metallic stent placement. CONCLUSION: Balloon dilatation is a safe and effective treatment for biliary-enteric strictures following pediatric liver transplantation.

Using pullback pressure measurements to identify venous stenoses persisting after successful angioplasty in failing hemodialysis grafts.

OBJECTIVE: We used pullback pressure measurements to identify venous stenoses persisting after angioplasty of failing hemodialysis grafts. MATERIALS AND METHODS: Fifty angioplasty procedures were performed in 32 patients with elevated venous pressures at dialysis. Grafts were initially evaluated on digital subtraction angiography, and all stenoses measuring greater than 50% on angiography underwent angioplasty. In successful cases (residual stenosis < 30%), pullback pressure measurements were obtained from the superior vena cava to the graft to identify hemodynamically significant (> 10 mm Hg) stenoses. These lesions were then treated with repeated angioplasty. RESULTS: Hemodynamically significant stenoses with a gradient range of 10-27 mm Hg (mean, 16 mm Hg) were found in nine (18%) of 50 procedures. All gradients occurred at sites of previous angioplasty. Repeated angioplasty of these stenoses performed with larger angioplasty balloons reduced gradients to less than 3 mm Hg in six stenoses and to 5 mm Hg in three stenoses. In this subgroup, primary patency was eight (89%) of nine stenoses at 1 month and 2 months and five (56%) of nine stenoses at 6 months. Using life table analysis, we found that primary patency of the entire population was 84% at 1 month, 66% at 2 months, and 47% at 6 months. The mean time between interventions was 6 months, and the thrombosis rate was 0.32 per year. CONCLUSION: Pullback pressure measurements are a useful adjunct to angiography to evaluate the hemodynamic results of angioplasty in patients with failing hemodialysis grafts.