Samer G. Zammar

Comparison of the Efficacy and Safety of Endovascular Coiling Versus Microsurgical Clipping for Unruptured Middle Cerebral Artery Aneurysms: A Systematic Review and Meta-Analysis.

OBJECTIVE Middle cerebral artery aneurysms (MCAAs) are regularly treated by both microsurgical clipping and endovascular coiling. We performed a systematic meta-analysis to compare the safety and efficacy of these 2 methods. METHODS Literature was reviewed for all studies reporting angiographic occlusion and/or functional outcomes in adults with unruptured MCAA treated by endovascular coiling or microsurgical clipping. All studies in English that reported results for adults (≥18 years) with unruptured MCAAs, from 1990 to 2011 were considered for inclusion. RESULTS Twenty-six studies involving 2295 aneurysms treated with clipping or coiling for unruptured MCAAs were included for analysis. There were 1530 aneurysms that were treated with clipping and 765 aneurysms treated with coiling. Pooled analysis revealed failure of aneurysmal occlusion in 3.0% (95% confidence interval [CI] 1.2%-7.4%) of clipped cases. Pooled analysis of 15 studies (606 aneurysms) involving coiling and occlusion revealed lack of occlusion rates of 47.7% (95% CI 43.6%-51.8%) with the fixed-effects model and 48.2% (95% CI 39.0%-57.4%) with the random-effects model. Thirteen studies examined neurological outcomes after clipping and were pooled for analysis. Both fixed-effect and random-effect models revealed unfavorable outcomes in 2.1% (95% CI 1.3%-3.3%) of patients. There were 17 studies evaluating potential unfavorable neurological outcomes after coiling that were pooled for analysis. Fixed-effect and random-effect models revealed unfavorable outcomes in 6.5% (95% CI 4.5%-9.3%) and 4.9% (95% CI 3.0%-8.1%) of patients, respectively. CONCLUSIONS Based on this systematic review and meta-analysis of unruptured MCAAs, after careful consideration of patient, aneurysmal, and treatment center factors, we recommend surgical clipping for unruptured MCAA.

The role of antiplatelet therapy in aneurysm coiling

Abstract Neurointerventional surgery offers the potential to deliver remarkable intravascular therapies for various neurovascular diseases and stroke. This approach, however, carries a risk of complications that need to be kept to a minimum. Thromboembolism is one of the most consequential complications of neurointerventional surgery in the treatment of intracranial aneurysms. Both antiplatelet and anticoagulant therapies have shown to reduce the risk of thromboembolism in this setting. In this paper, we review the role of antiplatelet therapy in the endovascular management of intracranial aneurysms. For unruptured aneurysms, the use of antiplatelet agents to pre-medicate patients before and during the procedure appears safe and effective in reducing the thrombotic risk. Abciximab has not been extensively studied, but seems to be safe as a salvage maneuver in the case of thrombus formation even in ruptured aneurysms (when the dome is relatively secure) with low rates of intraprocedure and procedure hemorrhagic complications. Further innovation and research are needed to further reduce thromboembolic risks of aneurysm coiling.

Microsurgical Treatment of Previously Coiled Intracranial Aneurysms: Systematic Review of the Literature

OBJECTIVE To assess indications, complications, clinical outcomes, and technical nuances of microsurgical treatment of previously coiled intracranial aneurysms. METHODS A systematic review of the literature was performed using PubMed/MEDLINE and EMBASE databases from January 1990 to December 2013. English-language articles reporting on microsurgical treatment of previously coiled intracranial aneurysms were included. Articles that involved embolization materials other than coils were excluded. Data on aneurysm characteristics, indications for surgery, techniques, complications, angiographic obliteration rates, and clinical outcomes were collected. RESULTS The literature review identified 29 articles reporting on microsurgical clipping of 375 previously coiled aneurysms. Of the aneurysms, 68% were small (<10 mm). Indications for clipping included the presence of a neck remnant (48%) and new aneurysmal growth (45%). Rebleeding before clipping was reported in 6% of cases. Coil extraction was performed in 13% of cases. The median time from initial coiling to clipping was 7 months. The angiographic cure rate was 93%, with morbidity and mortality of 9.8% and 3.6%, respectively. CONCLUSIONS Microsurgical clipping of previously coiled aneurysms can result in high obliteration rates with relatively low morbidity and mortality in select cases. Considerations for microsurgical strategies include the presence of sufficient aneurysmal tissue for clip placement and the potential need for temporary occlusion or flow arrest. Coil extraction is not needed in most cases.

Futuristic Three-Dimensional Printing and Personalized Neurosurgery

Figure 1. Continuous liquid interface production apparatus. From Tumbleston JR, Shirvanyants D, Ermoshkin N, Janusziewicz R, Johnson AR, Kelly D, Chen K, Pinschmidt R, Rolland JP, Ermoshkin A, Samulski ET, DeSimone JM: Additive manufacturing. Continuous liquid interface production of 3D objects. Science 347:1349-1352, 2015. Reprinted with permission from AAAS. Disruptive technologies are rare phenomena. However, when they do come about, they have the potential to change the course of entire industries. Such is the case with the new three-dimensional (3D) printing technology from Carbon3D Inc. (Redwood City, California, USA), dubbed Continuous Liquid Interface Production (CLIP). With its innovative approach to additive manufacturing, CLIP has the potential to usurp and revolutionize 3D printing, with reverberations into several fields, including neurologic surgery. Conventional additive manufacturing, like Polyjet, Fused Deposition Modeling (FDM), Stereolithography (SLA) and Laser Sintering technology (SLS), function by adding materials layer by layer. For these techniques, two-dimensional printing is repeated over and over again until a 3D physical rendering is produced. Consequently, such a process takes several hours and in most cases results in an unfinished and “pixelated-like” end product. A post-processing interval adds further time to the process. CLIP technology, as described by Tumbleston et al., prints 3D physical models in a continuous fashion as opposed to layer by layer in conventional machines. This approach capitalizes on 2 opposing forces: ultraviolet (UV) light that promotes polymerization of resin, in contrast to oxygen (O2), which inhibits the polymerization of resin. The apparatus itself consists of a bath filled with resin, an O2-permeable and UVpermeable membrane, a build support plate, and a UV imaging unit (Figure 1). Polymerization of the intended part begins when a continuous sequence of UV images is projected through the O2permeable, UV-transparent window below the resin bath; this creates a layering, whereby directly above the window a liquid dead zone rich in O2 exists, where no polymerization occurs. Directly above the dead zone, O2 concentration decreases, and polymerization of the resin and construction of the 3D model occur, guided by the projected UV images. Simultaneously, the 3D part is elevated out of the resin bath by a continuously elevating build support plate (Video I). This process can speed up 3D printing up to 100-fold, producing a high-resolution finished or near-finished product without the layerings of 3D printing. A job that used to take hours now takes only minutes to complete. Moreover, the spectrum of

Novel use of a double lumen balloon catheter for venous sinus thrombolysis and venoplasty

We describe the novel use of a double lumen balloon catheter for venous sinus thrombolysis and venoplasty. Cerebral venous sinus thrombosis is a rare disease that is usually treated with medical anticoagulation. In certain refractory cases, surgical or endovascular thrombolysis and thrombectomy may be required. A 48 year-old man on anticoagulation for cerebral venous sinus thrombosis presented with nausea, vomiting and worsening hemiparesis. The patient underwent endovascular venous sinus thrombolysis and venoplasty with continuous in situ tissue plasminogen activator (tPA) infusion over 48 hours. This novel approach to the endovascular treatment of venous sinus thrombosis, including the use of a double lumen balloon was advantageous, as it allowed direct infusion of tPA through the balloon catheter without having to exchange the balloon for a microcatheter.

Use of a harvested radial artery graft with preservation of the vena comitantes to reduce spasm risk and improve graft patency for extracranial to intracranial bypass: Technical note

BACKGROUND AND SIGNIFICANCE The vessels of choice for cerebrovascular high-flow direct bypass procedures are the radial artery and the saphenous vein. Radial artery grafts have become favored over saphenous vein grafts because of higher patency rates and better size matching to appropriate recipient vessels. Radial grafts are prone to spasm however, and this may be seen in 4-10% of cases and can be associated with ischemic sequelae. The standard technique for radial artery harvest calls for complete separation of the artery from its adventitial attachments and associated venous network. There is reason to believe that this could contribute to spasm risk and possibly even thrombosis. Radial graft outcomes appear to be improved when the vena comitantes is preserved in cardiac and peripheral applications. We report the novel use of a harvested radial artery graft with preservation of its venae comitantes for extracranial to intracranial bypass. CLINICAL PRESENTATION The patient is a 59-year-old male who had a blunt head trauma with associated loss of consciousness and who was led to the incidental discovery of a large fusiform middle cerebral artery (MCA) aneurysm. CONCLUSION Preservation of the vena comitantes when harvesting a radial arterial graft for bypass, along with dual (arterial and venous) anastomoses, and concomitant use of intra-operative vaso-dilatory maneuvers to prevent spasm, may improve overall graft patency and patient outcome.

Endovascular treatment of a complex bilobed left superior hypophyseal internal carotid artery aneurysm: a case illustration

We report the case of a 62-year-old female who presented for stent-assistant coiling of an incidental 11-mm complex bilobed left superior hypophyseal internal carotid artery aneurysm. A microcatheter was navigated into the aneurysm and trapped by a 37-mm stent. Using three-dimensional and two-dimensional coils, the elongated aneurysm was coiled. The bigger lobe was coiled first followed by the smaller lobe. Minimal residual filling of the smaller lobe will be re-evaluated at 6-month follow up. The patient tolerated the procedure well and no complications were encountered. The video can be found here: http://youtu.be/TrXfsaICQVo .

Pitfalls and Complications Management in the Endovascular Treatment of Aneurysms

This article reviews complications associated with the endovascular management of intracranial aneurysms, focusing on risk factors, avoidance, recognition, and management. Such complications can be devastating. Both neurologic and nonneurologic complications can occur. Several patient and procedure related parameters can increase the incidence of complications. Reduction of complication rates can be achieved by careful patient selection, meticulous planning and preparation for the procedure, anticipating potential complications, and preparing for their management. Tracking outcomes and a robust case conference can further enhance outcomes. Education of the care team and a collaborative environment can foster greater focus on avoidance of complications.

Hemicraniectomy for acute stroke in patients older than age 60: neurosurgeons on the frontlines of multidisciplinary stroke therapy.

8. Stupp R, Mason WP, van den Bent MJ, Weller M, Fisher B, Taphoorn MJ, Belanger K, Brandes AA, Marosi C, Bogdahn U, Curschmann J, Janzer RC, Ludwin SK, Gorlia T, Allgeier A, Lacombe D, Cairncross JG, Eisenhauer E, Mirimanoff RO; European Organisation for Research and Treatment of Cancer Brain Tumor and Radiotherapy Groups, National Cancer Institute of Canada Clinical Trials Group: Radiotherapy plus concomitant

A Biological Approach to Treating Brain Arteriovenous Malformations

F irst described by Luschka and Virchow in the mid 19th century, arteriovenous malformations (AVMs) are congenital vascular lesions consisting of anomalous tangles of vessels that have direct connections between arteries and veins without intervening capillaries. These lesions can cause death and disability. Microsurgery, endovascular embolization, and stereotactic radiosurgery (SRS) have the potential to improve on the natural history of these lesions, and in select cases may offer a cure when applied thoughtfully. A growing body of literature is beginning to reveal new ideas on how these lesions may be modulated biologically. AVMderived brain endothelial cells (AVM-BECs) are thought to be highly active cells demonstrating abnormal functions and overexpressing some proangiogenic growth factors. This group of cells is thought to undergo rapid proliferation and migration, and tend to produce aberrant tubule structures. Moreover, these cells have dysregulation of angiogenesis; for instance, thrombospondin-1 (TSP-1), which antagonizes Vascular Endothelial Growth Factor A (VEGF-A), a key proangiogenic molecule, is found to be at low Figure 1. Simulated tests for changes from background and effect of category on the responses of 50 000 neurons to 2 categories of stimuli (the responses are actually independent of category). (A) Scatter plot of the responses. The central diagonal line shows where responses to both categories would be equal; off diagonal lines show thresholds for detecting neurons with a selective response to category using a 1-way ANOVA. Plots along margins show the marginal distributions, with lines indicating the threshold for detection using a t-test, a 1⁄4 0.05 (dashed);a1⁄4 0.001 (dotted). (B) Scatter plot of all responses andwith projections for themore selective pretesta1⁄4 0.001. In this situation, neurons with large changes from baseline are now more likely to exhibit differences in category responses, the proportion of neurons with a category response is Pr1⁄4 .365, much higher than chance, but still due to random variation in this very selective and small neuronal sample. SCIENCE TIMES