Orlando Diaz

Spinal extradural arteriovenous fistulas : a clinical and radiological description of different types and their novel treatment with Onyx

OBJECT Spinal extradural (epidural) arteriovenous fistulas (AVFs) are uncommon vascular lesions of the spine with arteriovenous shunting located primarily in the epidural venous plexus. Understanding the complex anatomical variations of these uncommon lesions is important for management. The authors describe the different types of spinal extradural AVFs and their endovascular management using Onyx. METHODS Eight spinal extradural AVFs in 7 patients were studied using MR imaging, spinal angiography, and dynamic CT (DynaCT) between 2005 and 2009. Special consideration was given to the anatomy, pattern of venous drainage, and mass effect upon the nerve roots, spinal cord, and vertebrae. RESULTS The neuroaxial location of the 8 spinal extradural AVFs was lumbosacral in 1 patient, lumbar in 4 patients, thoracic in 2 patients, and cervical in 1 patient. Spinal extradural AVFs were divided into 3 types. In Type A spinal extradural AVFs, arteriovenous shunting occurs in the epidural space and these types have an intradural draining vein causing venous hypertension and spinal cord edema with associated myelopathy or cauda equina syndrome. Type B1 malformations are confined to the epidural space with no intradural draining vein, causing compression of the spinal cord and/or nerve roots with myelopathy and/or radiculopathy. Type B2 malformations are also confined to the epidural space with no intradural draining vein and no mass effect, and are asymptomatic. There were 4 Type A spinal extradural AVFs, 3 Type B1s, and 1 Type B2. Onyx was used in all cases for embolization. Follow-up at 6-24 months showed that 4 patients experienced excellent recovery. Three patients with Type A spinal extradural AVFs attained good motor recovery but experienced persistent bladder and/or bowel problems. CONCLUSIONS The current description of the different types of spinal extradural AVFs can help in understanding their pathophysiology and guide management. DynaCT was found to be useful in understanding the complex anatomy of these lesions. Endovascular treatment with Onyx is a good alternative for spinal extradural AVF management.

Temporal variations of wall shear stress parameters in intracranial aneurysms—importance of patient-specific inflow waveforms for CFD calculations

PurposeTo assess reliability of wall shear stress (WSS) calculations using computational fluid dynamics (CFD) dependent on inflow in internal carotid artery aneurysms (ICA).Materials and methodsSix unruptured ICA aneurysms were studied. 3D computational meshes were created from 3D digital subtraction angiographic images (Axiom Artis dBA, Siemens Medical Solutions). Transient CFD simulations (Fluent, ANSYS Inc.) were performed for two inflow conditions: (1) idealized averaged waveform from normal subjects (ID) and (2) patient-specific waveform (PS) measured with 2D phase contrast magnetic resonance imaging. Stability of calculation was assessed by comparing mean WSS (), temporal wall shear stress magnitude variation (ΔWSS), and oscillatory shear index (OSI, a measure of variation in the WSS direction) on the aneurysmal wall for both conditions.ResultsFor all cases, mean relative difference (PS−ID) of WSS () was −15% (range −32% to 11%). Mean ΔWSS difference was −29.3% ( −100% to 67%). Mean OSI difference was 7.5% (−12% to 40%). Large variations in histograms of these parameters were noted.ConclusionFor accurate calculations of WSS parameters, patient-specific information on physiological flow may be necessary. Results obtained with averaged or idealized flow waveforms may have to be interpreted with caution.

Aneurysm Study of Pipeline in an Observational Registry (ASPIRe)

Background and Objective: Few prospective studies exist evaluating the safety and efficacy of the Pipeline Embolization Device (PED) in the treatment of intracranial aneurysms. The Aneurysm Study of Pipeline In an observational Registry (ASPIRe) study prospectively analyzed rates of complete aneurysm occlusion and neurologic adverse events following PED treatment of intracranial aneurysms. Materials and Methods: We performed a multicenter study prospectively evaluating patients with unruptured intracranial aneurysms treated with PED. Primary outcomes included (1) spontaneous rupture of the Pipeline-treated aneurysm; (2) spontaneous nonaneurysmal intracranial hemorrhage (ICH); (3) acute ischemic stroke; (4) parent artery stenosis, and (5) permanent cranial neuropathy. Secondary endpoints were (1) treatment success and (2) morbidity and mortality at the 6-month follow-up. Vascular imaging was evaluated at an independent core laboratory. Results: One hundred and ninety-one patients with 207 treated aneurysms were included in this registry. The mean aneurysm size was 14.5 ± 6.9 mm, and the median imaging follow-up was 7.8 months. Twenty-four aneurysms (11.6%) were small, 162 (78.3%) were large and 21 (10.1%) were giant. The median clinical follow-up time was 6.2 months. The neurological morbidity rate was 6.8% (13/191), and the neurological mortality rate was 1.6% (3/191). The combined neurological morbidity/mortality rate was 6.8% (13/191). The most common adverse events were ischemic stroke (4.7%, 9/191) and spontaneous ICH (3.7%, 7/191). The complete occlusion rate at the last follow-up was 74.8% (77/103). Conclusions: Our prospective postmarket study confirms that PED treatment of aneurysms in a heterogeneous patient population is safe with low rates of neurological morbidity and mortality. Patients with angiographic follow-up had complete occlusion rates of 75% at 8 months.

Middle cerebral artery aneurysms: A single-center series comparing endovascular and surgical treatment

OBJECTIVE The optimal treatment for middle cerebral artery (MCA) aneurysms is controversial. MCA aneurysms have been considered more conducive to surgical treatment. Recent technology has led to successful endovascular treatment of MCA aneurysms. The objective of this study was to analyze the outcomes of endovascular and surgical treatment of MCA aneurysms as experienced by a single tertiary center. METHODS We retrospectively reviewed 90 MCA aneurysms in 84 patients treated from 2005 to 2010. They were separated into 2 groups: endovascular coiling, with 50 (59.5%) patients, and surgical clipping, with 34 (40.5%) patients. Outcome was based on complications, procedural morbidity and mortality, clinical and angiographic outcomes, and retreatment rates. Patients were further separated into ruptured and unruptured aneurysm groups. RESULTS Ruptured aneurysms were 10 of 50 (20%) and 9 of 34 (26.5%) patients in the endovascular and surgical groups, respectively. Procedure-related complications were 16% and 0% for the endovascular and surgical groups (P = .01), respectively. Overall rate of complete or near-complete occlusion at angiographic follow-up was 86% and 95% for the endovascular and surgical groups (P = .16), respectively. Proportion of patients with modified Rankin scale of 3 to 6 at 6 months follow-up was 10% and 5.9% for the endovascular and surgical groups (P = .5), respectively. The mean angiographic follow-up was 9.02 months (range 0 to 5.2 years). Retreatment rates were 14% and 0% for the endovascular and surgical groups, respectively (P = .01). CONCLUSIONS In this nonrandomized sample of 90 MCA aneurysms treated with endovascular coiling or neurosurgical clipping, we observed a similar clinical outcome based on the modified Rankin scale and angiographic occlusion. Complication and retreatment rates were higher but not significant for the endovascular group. Both treatment modalities are good alternatives and should be individualized based on aneurysm angioarchitecture and the patients general conditions.

Treatment of 14 intracranial aneurysms with the FRED system

Background Endovascular treatment of intracranial aneurysms via flow diversion has become increasingly popular over the past several years. The flow redirection endoluminal device (FRED; Microvention, Tustin, California, USA) system is a next generation closed cell paired stent flow diversion device. Objective Our initial clinical experience with the FRED system is described. We believe this series to be the first use of the FRED system in the western hemisphere. Methods 14 aneurysms were treated utilizing the FRED system in 13 patients. Post-deployment angiography and fluoro CTs were obtained in all cases. Results Immediate post-treatment angiography demonstrated reduced flow into all aneurysms although no long term angiographic data are yet available. The device proved technically easy to deploy and recapture after partial deployment if needed. No complications, technical or otherwise, were encountered. Radiographic visibility and ability to maintain its internal cylindrical shape in tortuous arteries, as demonstrated by fluoro CT, was at least as good as the pipeline embolization device. Conclusions The FRED system was technically easy to deploy with no procedural complications occurring in this first reported series of 14 aneurysms. The ability of the FRED system to be recaptured after partial deployment and to maintain its internal shape in tortuous vessels was demonstrated well. Long term clinical and angiographic follow-up along with prospective studies are now needed to ascertain the role of the FRED in intracranial aneurysm treatment.

Three-dimensional printing of anatomically accurate, patient specific intracranial aneurysm models.

Objective To develop and validate a method for creating realistic, patient specific replicas of cerebral aneurysms by means of fused deposition modeling. Methods The luminal boundaries of 10 cerebral aneurysms, together with adjacent proximal and distal sections of the parent artery, were segmented based on DSA images, and corresponding virtual three-dimensional (3D) surface reconstructions were created. From these, polylactic acid and MakerBot Flexible Filament replicas of each aneurysm were created by means of fused deposition modeling. The accuracy of the replicas was assessed by quantifying statistical significance in the variations of their inner dimensions relative to 3D DSA images. Feasibility for using these replicas as flow phantoms in combination with phase contrast MRI was demonstrated. Results 3D printed aneurysm models were created for all 10 subjects. Good agreement was seen between the models and the source anatomy. Aneurysm diameter measurements of the printed models and source images correlated well (r=0.999; p<0.001), with no statistically significant group difference (p=0.4) or observed bias. The SDs of the measurements were 0.5 mm and 0.2 mm for source images and 3D models, respectively. 3D printed models could be imaged with flow via MRI. Conclusions The 3D printed aneurysm models presented were accurate and were able to be produced inhouse. These models can be used for previously cited applications, but their anatomical accuracy also enables their use as MRI flow phantoms for comparison with ongoing studies of computational fluid dynamics. Proof of principle imaging experiments confirm MRI flow phantom utility.

Final results of the US humanitarian device exemption study of the low-profile visualized intraluminal support (LVIS) device

Introduction The low-profile visualized intraluminal support (LVIS) device is a new, braided, intracranial microstent designed for stent-assisted coiling. Objective To present the results of a single-arm, prospective, multicenter trial of the LVIS for treatment of wide-necked intracranial aneurysms. Methods 31 patients with unruptured, wide-necked (neck ≥4 mm or dome:neck ratio ≤2) intracranial aneurysms were treated with the LVIS device and bare platinum coils at six US centers (investigational device exemption G110014). Clinical follow-up was conducted at 30 days and 6 months. Angiographic follow-up was performed at 6 months. The primary safety endpoint was any major stroke or death within 30 days or major ipsilateral stroke or neurological death within 6 months. ‘Probable benefit’ was defined as ≥90% angiographic occlusion at 6 months. An independent core laboratory adjudicated the angiographic results. An independent clinical events committee adjudicated the clinical endpoints. Results Average aneurysm size was 7.2 mm (SD 3.8) and average neck width was 4.6 mm (SD 1.8). 68% of patients had a dome:neck ratio ≤2. LVIS placement was technically successful in 29/31 patients (93.5%). No primary safety endpoints occurred during the study (0%). No patient had a higher modified Rankin Score at 6 months than at baseline. 26/28 (92.9%) treated aneurysms with 6-month angiographic follow-up demonstrated ≥90% angiographic occlusion. 21/28 (75%) were completely occluded at follow-up. Conclusions The LVIS device facilitated the coil embolization of wide-necked intracranial aneurysms with high rates of technical success, an excellent safety profile, and very high rates of complete and near-complete occlusion at follow-up. Trial registration number NCT01541254.

Mid and long term outcomes of dural arteriovenous fistula endovascular management with Onyx. Experience of a single tertiary center

Introduction The natural history of intracranial dural arteriovenous fistulas (DAVFs) with cortical venous drainage is unfavorable, and treatment is recommended in most cases. Early reports have documented excellent initial clinical and radiographic outcomes after Onyx embolization of DAVFs but little evidence is available regarding the long term durability of this technique. Methods We retrospectively reviewed a database of 63 DAVFs in 53 consecutive patients who underwent Onyx embolization of a DAVF between 2001 and 2012 at our institution. Cognard types I and III were seen most commonly. Results A total of 72 Onyx embolization procedures were successfully completed during the study period, resulting in complete or near complete occlusion by the end of the study period in 58 (92.1%) DAVFs. For DAVFs in which complete or near complete obliteration was attained, stability of obliteration at 6, 12, 24, and 46 months was 100%, 95.4%, 93.8%, and 92.3%, respectively. DAVF recanalization/regrowth was discovered on delayed follow-up angiography in only five instances in which immediate post-embolization angiography revealed complete obliteration. Complications were seen in seven embolization procedures and included cranial nerve palsies (n=3), embolic infarcts (n=2), intraparenchymal hemorrhage (n=1), and unintentional stent deployment (n=1). Conclusions Early evidence has indicated that endovascular Onyx embolization is safe and effective at achieving an initial angiographic cure. Results of our series suggest that angiographic and clinical outcomes of Onyx embolization remain relatively stable at mid and long term follow-up.

In-Vivo Quantification of Wall Motion in Cerebral Aneurysms from 2D Cine Phase Contrast Magnetic Resonance Images

PURPOSE The quantification of wall motion in cerebral aneurysms is of interest for the assessment of aneurysmal rupture risk, for providing boundary conditions for computational simulations and as a validation tool for theoretical models. MATERIALS AND METHODS 2D cine phase contrast magnetic resonance imaging (2D pcMRI) in combination with quantitative magnetic resonance angiography (QMRA) was evaluated for measuring wall motion in 7 intracranial aneurysms. In each aneurysm, 2 (in one case 3) cross sections, oriented approximately perpendicular to each other, were measured. RESULTS The maximum aneurysmal wall distention ranged from 0.16 mm to 1.6 mm (mean 0.67 mm), the maximum aneurysmal wall contraction was -1.91 mm to -0.34 mm (mean 0.94 mm), and the average wall displacement ranged from 0.04 mm to 0.31 mm (mean 0.15 mm). Statistically significant correlations between average wall displacement and the shape of inflow curves (p-value < 0.05) were found in 7 of 15 cross sections; statistically significant correlations between the displacement of the luminal boundary center point and the shape of inflow curves (p-value < 0.05) were found in 6 of 15 cross sections. CONCLUSION 2D pcMRI in combination with QMRA is capable of visualizing and quantifying wall motion in cerebral aneurysms. However, application of this technique is currently restricted by its limited spatial resolution.

Preoperative Onyx embolization of hypervascular head, neck, and spinal tumors. Experience with 100 consecutive cases from a single tertiary center

Background/purpose Preoperative embolization of head, neck, and spinal tumors is frequently used to control tumor bleeding, reduce operative time, and achieve better resection. Numerous embolic materials have been used. The use of the liquid embolic agent Onyx is rapidly increasing but current experience is limited to small case series. Our purpose was to evaluate the indications, techniques, angiographic devascularization, blood loss, outcome, and general efficacy of preoperative tumor embolization with Onyx in a large series. Methods Retrospective analysis of 100 consecutive cases of head, neck, and spinal tumors embolized with Onyx and prospective follow-up. Results 100 patients (63 women, 37 men) were included. Tumors included 39 meningiomas, 23 metastases, 16 parangliomas, five juvenile nasal angiofibromas, five giant cell bone tumors, three Ewings sarcomas, three hemangiomas, three hemangioblastomas, two multiple myelomas, and one osteoblastoma. In all patients, angiographic analysis of the feeding arteries and branches was performed and all embolizations were completed in a single session. Additional materials were used in 28 patients. No mortality or major complications were observed. Minor complications were seen in 11 patients. 85 patients underwent surgery; 79 within the next 48 h and six of them 4–188 days after embolization. Conclusions Embolization of intracranial, head, neck, and spinal tumors with Onyx is effective and safe by a transarterial route or by direct puncture. Onyx penetrates well into the tumor capillary with less arterial catheterization. Studies are necessary to establish long term utility in adjunct or palliative tumor embolization.