Percutaneous intracranial stent placement for aneurysms

Stent-Assisted Coiling of Aneurysm in a Persistent Primitive Lateral Vertebrobasilar System

Fenestrations of cerebral arteries are relatively common. Knowledge of their structure has recently gained clinical significance with increasing awareness of fenestration aneurysms. Persistent primitive lateral vertebrobasilar (PPLVB) anastomoses are an extreme end of the embryologic mishaps causing these fenestrations, and their occurrence has only been reported twice. We report the first case of an aneurysm within the PPLVB in a patient with unilateral subclavian stenosis. The unique anatomy of these aneurysms and relation with important perforators and brainstem make surgery extremely difficult and require advanced endovascular techniques like balloon remodeling and stent assistance. Three-dimensional rotational angiography can help in providing clarity to the aneurysmal anatomy and planning treatment. The purpose of this case report is to bring to notice the possibility of such aneurysms and use the unique anatomy to understand various tools available in the endovascular surgeon's armamentarium.

Using a covered stent for large cerebral aneurysms treated with stent-assisted coiling

PURPOSE

The purpose of this article is to evaluate the efficacy and safety of covered stent implantation for large intracranial aneurysms treated with stent-assisted coiling.

MATERIALS AND METHODS

Seven patients with a cerebral aneurysm were selected for this study. The aneurysms were located at the cavernous segment of the internal carotid artery in three cases, the supraclinoid segment in two and the vertebrobasilar junction in one. Aneurysm diameter was 10-25 mm. Mass effect symptoms occurred in six patients, epistaxis in one and subarachnoid hemorrhage in one. All patients underwent endovascular reconstruction with stent-assisted coiling and a covered stent. Five had undergone conventional endovascular embolization with stent-assisted coiling three to six months previously; the covered stent was then navigated through the existing stent and deployed to cover the aneurysm neck. In two cases, the covered stent was deployed after stent-assisted coiling in a single procedure.

RESULTS

Angiography showed that all aneurysms were excluded from the circulation and parent arteries were preserved. No technical adverse events occurred. At the one- to two-year follow-up, complete resolution of clinical symptom had occurred in six patients and partial resolution in one. No recurrent aneurysm filling and no hemodynamic stenosis was observed.

CONCLUSION

Endovascular reconstruction combining a covered stent with stent-assisted coiling could be an effective and safe strategy for the treatment of large cerebral aneurysms.

Three-dimensional hemodynamic design optimization of stents for cerebral aneurysms

Flow-diverting stents occlude aneurysms by diverting the blood flow from entering the aneurysm sac. Their effectiveness is determined by the thrombus formation rate, which depends greatly on stent design. The aim of this study was to provide a general framework for efficient stent design using design optimization methods, with a focus on stent hemodynamics as the starting point. Kriging method was used for completing design optimization. Three different cases of idealized stents were considered, and 40–60 samples from each case were evaluated using computational fluid dynamics. Using maximum velocity and vorticity reduction as objective functions, the optimized designs were identified from the samples. A number of optimized stent designs have been found from optimization, which revealed that a combination of high pore density and thin struts is desired. Additionally, distributing struts near the proximal end of aneurysm neck was found to be effective. The success of the methods and framework devised in this study offers a future possibility of incorporating other disciplines to carry out multidisciplinary design optimization.

Bilateral intracavernous carotid artery aneurysms presenting as diplopia in a young patient

Introduction. Bilateral intracavernous carotid artery aneurysms (ICAAs) are extremely rare and difficult to treat. Case Report. A 26-year-old female presented in our clinic with acute diplopia due to oculomotor nerve palsy on the left side. Magnetic resonance imaging of the brain showed two heterogeneously enhanced masses indicating bilateral ICAA. An endovascular coil embolization was performed on the left side successfully, resulting in resolution of her symptoms. Conclusion. Thorough systemic evaluation in young patients with diplopia can reveal life-threatening underlying pathology and prevent major complications.

Enterprise stent-assisted coiling of wide-necked intracranial aneurysms: clinical and angiographic follow-up

We evaluate and report our clinical and angiographic outcomes associated with stent-assisted coil embolization of wide-necked intracranial aneurysms using the Enterprise stent. One hundred sixty-nine patients diagnosed with 182 wide-necked intracranial aneurysms underwent placement of the Enterprise stent between April 2009 and October 2011. Demographic information, procedural data, procedure-related complications, angiographic results, and clinical outcomes were reviewed and evaluated. Stent deployment was successful in 166 out of 169 procedures (98.2%). Four patients had acute procedure-related complications, including th romboembolism in three patients and aneurysm perforation resulting in the death of one patient. Immediate angiographic results showed complete occlusion in 101 aneurysms (56.4%) and near-complete occlusion in 55 aneurysms (30.7%). Follow-up angiography was performed in 108 patients with 119 aneurysms at a mean of 8.1 months: complete occlusion was observed in 95 aneurysms (79.8%) and near-complete occlusion was found in 12 aneurysms (10.1%). Delayed intra-stent thromboses were observed in two patients, and asymptomatic in-stent stenosis was observed in one patient. Ten aneurysms (8.4%, 10/119) demonstrated recanalization, all of which were subsequently recoiled successfully. Clinical follow-up was obtained for 132 patients at a mean of 11.4 months, out of which 118 (89.4%) had favorable clinical outcomes as determined using a modified Rankin Scale (mRS) ≤ 1. The rates of procedure-related mortality and permanent morbidity were 0.6% (1/169) and 2.3%( 3/132), respectively. This study adds to the current body of evidence supporting the Enterprise stent as an effective and safe tool for the treatment of wide-necked intracranial aneurysms because it results in more complete occlusion and lower complication rates.

Stent-supported aneurysm coiling: a literature survey of treatment and follow-up

BACKGROUND AND PURPOSE

Stent-supported aneurysm coiling has been utilized with increasing frequency over the past few years, particularly for addressing treatment of complex and wide-neck aneurysms. A sizable body of literature describing various experiences with stent-supported coiling now exists. The purpose of this research was to carry out a comprehensive literature survey of stent-supported aneurysm coiling.

MATERIALS AND METHODS

A survey of papers reporting results with stent-assisted aneurysm coiling through January 2011 was conducted to identify the prevalence of stent-related and other complications, occlusion rates, and clinical and angiographic follow-up data.

RESULTS

Thirty-nine articles with 1517 patients met inclusion criteria for initial analysis, follow-up analysis, or both. Overall, 9% of cases were confounded by a technical stent-related issue, including 4% failure of deployment. The overall procedure complication rate was 19%, with periprocedural mortality of 2.1%. Approximately 45% of aneurysms were completely occluded at first treatment session, increasing to 61% on follow-up. Approximately 3.5% in-stent stenosis and 0.6% stent occlusion were observed at angiographic follow-up. Delayed stroke or transient ischemic attack was reported in 3% of subjects. Within a subset of articles, the incidence of stent-related issues in the first 10 patients was significantly higher than in subsequent subjects, supporting the notion of a procedural "learning curve."

CONCLUSIONS

In experienced hands, the morbidity of stent-supported coiling is somewhat higher compared with "traditional" coiling. As might be expected, execution of the procedure appears improved with experience. Complete occlusion rates remain somewhat low. More and longer term angiographic follow-up information is needed to understand delayed stent-related issues and to better define the durability of treatment.

Potential advantages and limitations of the Leo stent in endovascular treatment of complex cerebral aneurysms

OBJECTIVE

The Leo self-expandable stent is a new retractable stent that is delivered via a conventional catheter. The aim of this study was to evaluate the use of this stent for endovascular treatment of complex aneurysms.

METHODS

Twenty-eight complex cerebral aneurysms (27 saccular and 1 fusiform) in 28 patients were treated electively. They were located at the internal carotid artery (17), basilar trunk (3), anterior cerebral artery (1), anterior communicating artery (3), vertebral artery (2) and middle cerebral artery (2). One aneurysm exhibited recanalization after primary endovascular treatment without stent. Clinical outcome was assessed with the modified Glasgow Outcome Scale.

RESULTS

Deployment of Leo stent was successful in 26 lesions, and difficulties in stent positioning due to tortuous cerebral circulation in 2 cases, which were treated with Neuroform stent. Additional coil embolization was performed in 26 lesions. No permanent neurological deficits were encountered consequent to endovascular procedure. Complete or partial occlusion immediately after stent deployment was achieved in all aneurysms. There was no immediate coil embolization was chosen in 3 cases because of subsequent reduced filling of the aneurysms with contrast agent on angiograms. There were 3 asymptomatic parent artery occlusion related to the deployment of the Leo stent, one stent migration. Follow-up revealed patent stents in the remaining cases. No angiographic recurrences arose.

CONCLUSION

The Leo stent is very useful for endovascular treatment of complex cerebral aneurysms because it is easy to navigate and place precisely. A drawback is that in-stent thrombosis caused by stent placement and stiffer delivery catheters to place larger stents.

Alteration of intra-aneurysmal hemodynamics for flow diversion using enterprise and vision stents

OBJECTIVE

Flow diversion is a novel concept for intracranial aneurysm treatment. The recently developed Enterprise Vascular Reconstruction Device (Codman Neurovascular, Raynham MA) provides easy delivery and repositioning. Although designed specifically for restraining coils within an aneurysm, this stent has theoretical effects on modifying flow dynamics, which have not been studied. The goal of this study was to quantify the effect of single and multiple self-expanding Enterprise stents alone or in combination with balloon-mounted stents on aneurysm hemodynamics using computational fluid dynamics (CFD).

METHODS

The geometry of a wide-necked, saccular, basilar trunk aneurysm was reconstructed from computed tomographic angiography images. Various combinations of 1-3 stents were "virtually" conformed to fit into the vessel lumen and placed across the aneurysm orifice. CFD analysis was performed to calculate hemodynamic parameters considered important in aneurysm pathogenesis and thrombosis for each model.

RESULTS

The complex aneurysmal flow pattern was suppressed by stenting. Stent placement lowered average flow velocity in the aneurysm; further reduction was achieved by additional stent deployment. Aneurysmal flow turnover time, an indicator of stasis, was increased to 114-117% for single-stent, 127-128% for double-stent, and 141% for triple-stent deployment. Furthermore, aneurysmal wall shear stress (WSS) decreased with increasing number of deployed stents.

CONCLUSION

This is the first study analyzing flow modifications associated with placement of Enterprise stents for aneurysm occlusion. Placement of 2-3 stents significantly reduced intra-aneurysmal hemodynamic activities, thereby increasing the likelihood of inducing aneurysm thrombotic occlusion.

Endovascular treatment of a large aneurysm arising from a basilar trunk fenestration using the waffle-cone technique

OBJECTIVE

Endovascular treatment of large intracranial aneurysms arising from a fenestrated parent vessel may prove particularly difficult. We present a case of a large, broad-based aneurysm arising from a proximal basilar artery (BA) fenestration treated with the waffle-cone technique. Technical nuances and indications for this treatment option are reviewed.

CLINICAL PRESENTATION

A 38-year-old man presented with headache, blurred vision, and dizziness. Angiography demonstrated an 11 x 14-mm BA aneurysm associated with the proximal portion of a BA fenestration.

TECHNIQUE

A 28 x 4.5-mm Enterprise stent was placed from the right vertebral artery directly into the aneurysm. The stent tines were allowed to flare out in the aneurysm neck creating the "waffle cone." The aneurysm was then coiled with a series of Presidio coils.

CONCLUSION

Use of the waffle-cone technique for stent placement resulted in nearly complete embolization of the aneurysm, retention of the entire coil mass in the dome, and preservation of flow through both vertebral arteries and both limbs of the fenestration.

Endovascular treatment for cerebral aneurysms using stents

Endovascular stent placement combined with coil embolization is an established procedure for the treatment of intracranial aneurysms. We describe lesion outcome using stents for the treatment of intracranial aneurysms. Sixty-nine patients (30 females and 39 males; age range 12-78 years) treated with stent placement at Beijing Tiantan Hospital over a six-year period. Seventy- six cerebral aneurysms were encountered and 74 lesions were treated with 79 stents. Outcome was evaluated using the Glasgow Outcome Scale (GOS) score during a mean follow-up period of 32 months. Of the 74 stented aneurysms, 34 (45.9%) were located in the anterior circulation and 40 (54.1%) in the posterior circulation. Forty-eight (64.9%) aneurysms were small and 26 (35.1%) were large or giant. In 67 (90.5%) aneurysms embolization was completed by packing the aneurysm sac with platinum coils. In five small fusiform and four saccular aneurysms, the stent was used alone. Six procedure-related complications were observed and a cause of death in 7.2% of the patients. Follow-up angiography obtained at three months to one year in 68 (91.9%) aneurysms demonstrated complete occlusion in 43 aneurysms with a progressive thrombosis rate of 19.4% (six out of 31 aneurysms). Aneurysm recurrence occurred in four (5.8%) patients, three were treated with coil embolization and one with placement of another stent. Overall long-term outcome was good (GOS Score 4 or 5) in 92.8%, and fatal (GOS Score 1) in 7.2% of the patients. Intracranial stents can be a useful addition to coil embolization for complex broad-based aneurysms. Favorable overall long-term outcome can be achieved in 92.8% of patients when using endovascular stent placement techniques.

Bilateral giant cavernous carotid artery aneurysms in a child with juvenile Paget's disease

BACKGROUND

Juvenile Paget disease (JPD) is a rare genetic bone disorder, also affecting the immune and vascular systems. We describe the first ever case of JPD associated with bilateral giant cavernous carotid artery aneurysms in a child.

CASE DESCRIPTION

A child with known JPD presented with left abducens nerve palsy and a computed tomographic angiogram revealed bilateral giant cavernous carotid artery aneurysms. He underwent a left-sided superficial temporal artery to middle cerebral artery bypass and endovascular carotid artery occlusion, followed by an identical procedure on the right side 3 months later and made an event-free recovery without any new neurological deficits.

CONCLUSIONS

This previously unreported association poses the question of determining the optimal management strategy for such cases. The pathophysiology and clinical features of JPD are discussed, with special emphasis on the management of giant cavernous carotid aneurysms in this subgroup of individuals.

Preliminary use of the Leo stent in the endovascular treatment of wide-necked cerebral aneurysms

BACKGROUND

Currently available stents for intracranial use usually are Neuroform (Boston Scientific/Target, Fremont, CA) and Leo (Balt, Montmorency, France) stents. We present the results of our initial experience in using the Leo stent to treat patients with wide-necked cerebral aneurysms.

METHODS

Fifteen consecutive patients with wide-necked intracranial aneurysm were treated with a combined approach that consisted of delivery of a flexible self-expending neurovascular stent through a microcatheter to cover the neck of the aneurysm and subsequent filling of the aneurym with coils through the stent interstices. We assessed the clinical history, aneurysm dimensions, and technical details of the procedures, including any difficulties with stent deployment, degree of aneurysm occlusion, and complications.

RESULTS

During a 1-year period, 15 patients with 17 broad-necked aneurysms (n = 13; average neck length, 5.1 mm; average aneruysm size, 9 mm) were treated with the Leo stent. Fifteen stents were deployed successfully; two failed. Of the coiled aneurysms, complete or subtotal (more than 95%) occlusion was achieved in 11 aneurysms, and partial occlusion was achieved in 2 aneurysms. One patient had multiple stents placed. One patient had a ruptured aneurysm at the time of treatment. Technical problems included difficulty in deploying the stent (n = 2). Two periprocedural thromboembolic complications occurred. One patient had palsy after thrombolysis was attempted. The other patient made an excellent functional recovery after undergoing successful thrombolysis of a thrombosed internal carotid artery stent.

CONCLUSIONS

Preliminary data demonstrated that the Leo stent is useful device for the treatment of patients with wide-necked aneurysms. In cases with tortuous cerebral vasculature, delivery and deployment may be technically challenging. Clinically significant complications are uncommon.

Ten-year follow-up of giant basilar aneurysm treated by sole stenting technique: a case report

Introduction

The sole stenting technique has emerged as a new tool for the management of intracranial aneurysms. However, several concerns have emerged about the long-term behavior of intracranial stents, particularly their safety and efficacy.

Case presentation

We present the first case of an intracranial aneurysm intentionally treated with the sole stenting technique. After ten years of clinical and imaging follow-up, the lesion has healed and no intrastent stenosis is observed.

Several issues concerning this technique are discussed. For instance, the modification of the angle and intra-aneurysmal thrombosis may account as positive effects; negative outcomes include in-stent thrombosis or stenosis.

Conclusions

This case report, involving a long clinical and imaging follow-up, provides an example of the effectiveness, safety, durability and simplicity of the sole stenting technique in the management of intracranial aneurysms.

Thin film nitinol microstent for aneurysm occlusion

Thin film nitinol produced by sputter deposition was used in the design of microstents intended to treat small vessel aneurysms. Thin film microstents were fabricated by "hot-target" dc sputter deposition. Both stress-strain curves and differential scanning calorimetry curves were generated for the film used to fabricate stents. The films used for stents had an A(f) temperature of approximately 36 degrees C allowing for body activated response from a microcatheter. The 10 microm film was only slightly radio-opaque; thus, a Td marker was attached to the stents to guide fluoroscopic delivery. Thin film microstents were tested in a flow loop with and without nitinol support skeletons to give additional radial support. Stents could be compressed into and easily delivered with <3 Fr catheters. Theoretical frictional and wall drag forces on a thin film nitinol small vessel vascular stent were calculated, and the radial force exerted by thin film stents was evaluated theoretically and experimentally. In vivo studies in swine confirmed that thin film nitinol microstents could be deployed accurately and consistently in the swine cranial vasculature.

Vertebral dissecting aneurysm treated with wingspan stent deployment and detachable coils. A technical note

We describe the first documented endovascular treatment of vertebral dissecting aneurysm using a Wingspan stent and detachable coils. A 54-year-old man presented with a nonruptured vertebral dissecting aneurysm. Because of the dissecting nature of the vertebral aneurysms, a 3x15-mm Wingspan stent was placed in the left vertebral artery. One month later, several detachable coils were introduced into the aneurysm. Six-month follow-up angiogram confirmed the obliteration. Vertebral dissecting aneurysm can be treated with Wingspan stent placement and detachable coils.

Endovascular Treatment of Fusiform and Wide-Necked Intracranial Aneurysms with the Neuroform 3TM and Detachable Coils

Reconstructive treatments using stents improve occlusion rate of broad-necked intracranial aueurysms and protect parent vessels. Recently, the Neuroform stent has been developed and we evaluated it use for the treatment of fusiform and broad-necked intracranial aneurysms. Seventeen fusiform and broad-necked intracranial aneurysms in 15 patients were treated electively. Eight aneurysms were located at the internal carotid artery, five in the vertebral artery, one in the basilar tip, one in the middle cerebral artery, one in the posterior cerebellar artery and one in the posterior inferior cerebellar artery. Previous attempts with the remodeling technique had been judged technically difficult in all cases, and combined stent placement across the aneurysm neck was performed with subsequent coiling of the sac. Aneurysm diameter varied from 4 to 30 mm. Sixteen aneurysms in 15 patients were treated with this procedure. There were no stent deployment failures. All aneurysms were initially stented, followed by coil placement. Complete or subtotal (>95%) occlusion was achieved in six patients, and partial occlusion (<95%) was achieved in nine. The periprocedural rate of stroke or death was 0%. Angiographic follow-up was obtained in ten patients. Neurological status remained well in all patients at a mean clinical follow-up of 6.2±3.2 months. Primary and recurrent treatment of fusiform and wide-necked intracranial aneurysms using the Neuroform stent is feasible and effective. No permanent neurological deficits were associated with stent deployment. Short-term follow-up identified intact parent arteries and stable occlusion rates in the majority of cases.

Guidewire Tip Detachment during Stent-Assisted Coiling of an Intracranial Aneurysm

Endovascular treatment of complex intracranial lesions often requires use of two different microcatheters or micro-guidewires. A basilar artery aneurysm was treated with microstent-assisted coiling. During the procedure a microwire severed and the distal platinum portion of the wire was left after unsuccessful attempts to retrieve it. The patient remains asymptomatic. The proximal part of the microwire was analyzed and additional experiments indicate that it may have detached by electrolytic corrosion.

Medium-Term Results Using the Leo Self-Expanding Stent in the Treatment of Complex Intracranial Aneurysms

The preliminary experience with the Leo microstent in combination with detachable coils for the treatment of patients with wide-necked cerebral aneurysms is reported, and the technical complications and recommendations for optimum placement and deployment are discussed. Thirty two patients identified as harboring wide-necked aneurysm were selected for stent-assisted coiling. Aneurysms were paraophthalmic-cavernous in 13 cases, eight were located at the posterior communicating artery, four at the basilar artery, three at the vertebral arteries, two at the posterior cerebral arteries, one at the right middle artery, and one at the right posterior inferior cerebellar artery. After appropriate antiplatelet therapy, the Leo stent was delivered to the aneurysm site and positioned without difficulty, except in four cases requiring the use of steam to shape the tip of the Vasco microcatheter. Angiographic follow-up was undertaken at six months in 32 patients, at one year in 27 patients, and at two years in 20 patients. Stent placement in the desired position with complete or near complete occlusion of the aneurysm was feasible in all patients. In one patient, the stent was slightly displaced during microwire manipulation for aneurysm microcatheterization. Two-year angiography in 20 patients showed 18 complete occlusions and two aneurysms with a minimal residual neck. The Leo stent represents a significant advancement in the vascular treatment of intracranial aneurysms providing high radial force and an easy delivery system i.e., it is a feasible, secure and effective system.

Anatomic results and complications of stent-assisted coil embolization of intracranial aneurysms

SUMMARY

The purpose of this study was to evaluate and report our anatomic results and complications associated with stent-assisted coil embolization of intracranial aneurysms using the Neuroform stent. From September 2003 to August 2007, 127 consecutive patients (ruptured 50, 39.4%; unruptured 77, 60.6%) underwent 129 stent-assisted coil embolization procedures to treat 136 aneurysms at our institution. Anatomic results at follow-up, procedure-related complications, and morbidity/mortality were retrospectively reviewed. Stent deployment was successful in 128 out of 129 procedures (99.2%). Forty-seven patients presented with 53 procedure-related complications (37.0%, 47/127). Thromboembolic events (n=17, 13.4%) were the most common complications, followed by intraoperative rupture (n=8, 6.3%), coil herniation (n=5, 3.9%), and postoperative rupture (n=4, 3.1%). For thromboembolic events, acute intra-procedural instent thromboses were observed in two patients and subacute or delayed in-stent thromboses in three patients. Overall mortality rate was 16.5% (21/127) and procedure-related morbidity and mortality rates were 5.5% (7/127) and 8.7% (11/127) retrospectively. Patients with poor grade subarachnoid hemorrhage (Hunt and Hess grade IV or V; 25/127, 19.7%) exhibited 56% (14/25) overall mortality rate and 24% (6/25) procedure-related mortality rate. Immediate angiographic results showed complete occlusion in 31.7% of aneurysms, near-complete occlusion in 45.5%, and partial occlusion in 22.8%. Sixty nine patients in 70 procedures with 77 aneurysms underwent angiographic followup at six months or later. Mean follow-up period was 13.7 months (6 to 45 months). Complete occlusion was observed in 57 aneurysms (74.0%) and significant in-stent stenosis was not found. Thromboembolism and intra/postoperative aneurysm ruptures were the most common complications and the main causes of procedure-related morbidity and mortality. Patients with poor grade subarachnoid hemorrhage showed poor clinical outcomes. Since most complications were induced by stent manipulation and deployment, it is mandatory to utilize these devices selectively and cautiously. While the follow- up angiographic results are promising, further studies are essential to evaluate safety, efficacy, and durability of the Neuroform stent.

Use of the sole stenting technique for the management of aneurysms in the posterior circulation in a prospective series of 20 patients

Object

The use of intracranial stents in stent-assisted coil embolization is now a current neurosurgical practice worldwide. The clinical utility of these stents in the sole stenting (SS) technique, however, has not been thoroughly described, and the published reports of this experience are scarce. This study was designed to evaluate SS treatment of dissecting and nondissecting aneurysms of the posterior circulation.

Methods

This prospective and descriptive study was conducted in 20 consecutive patients who harbored single aneurysms of the posterior circulation and who were treated using the SS approach in the last 3 years. The clinical and radiological assessment and follow-up of the patients were evaluated using the modified Rankin scale as well as with computed tomography angiography and digital subtraction angiography at discharge and at 1, 3, 6, and 12 months.

Results

Eleven of the 20 patients had subarachnoid hemorrhages, 3 presented with ischemia, 1 presented with brainstem compression, and the remaining 5 patients had incidentally discovered, asymptomatic lesions. Only 1 patient had a complication (occipital infarction) attributable to the SS procedure. One patient died of rebleeding 2 weeks after the procedure. At 1 month, 40% of the patients had a subtotal or total occlusion, which increased to 55% at 3 months and 85% at 6 months, with a final subtotal or total occlusion rate of 80% at 1 year. The SS procedure in 1 case was considered a failure at 6 months because no change had been noted since the 1-month follow-up. One case showed partial occlusion and 1 case showed recanalization.

Conclusions

Use of SS for aneurysms in the posterior circulation complex is a safe and effective technique, demonstrating an occlusion rate of 80% at the 1-year follow up.

Efficacy and limitations of the neuroform stent system for intracranial aneurysms

SUMMARY

We performed aneurysm embolization in seven patients using a self-expandable Neuroform stent (Boston Scientific/Target, Fremont, CA) and coils to cover the aneurysm neck and fill the aneurysm sac. Seven patients with an average age of 45 were treated in the period from October 2002 to July 2003. The aneurysm lesions involved the basilar trunk in one case, the basilar-superior cerebellar artery in one case, the internal carotid artery in four cases, and the middle cerebral artery in one case. The ruptured lesions involved the internal carotid artery in one case and the middle cerebral artery in one case. We used a Neuroform stent measuring 4.5 x 20 mm in four cases, 4.5 x 15 mm in two cases, 3.5 x 20 mm in one case, and 3.5 x 15 mm in one case. We performed aneurysm coil embolization after Neuroform stenting in all cases without development of neurological deficits caused by the interventional procedure. In performing these procedures, we investigated the efficacy and limitations of the Neuroform stent system for intracranial aneurysms. The advantages of Neuroform self-expanding stents include better flexibility and adaptability to different vessel sizes, but this stent system presents various technical difficulties during delivery.

Comparison of two stents in modifying cerebral aneurysm hemodynamics

There is a general lack of quantitative understanding about how specific design features of endovascular stents (struts and mesh design, porosity) affect the hemodynamics in intracranial aneurysms. To shed light on this issue, we studied two commercial high-porosity stents (Tristar stent and Wallstent) in aneurysm models of varying vessel curvature as well as in a patient-specific model using Computational Fluid Dynamics. We investigated how these stents modify hemodynamic parameters such as aneurysmal inflow rate, stasis, and wall shear stress, and how such changes are related to the specific designs. We found that the flow damping effect of stents and resulting aneurysmal stasis and wall shear stress are strongly influenced by stent porosity, strut design, and mesh hole shape. We also confirmed that the damping effect is significantly reduced at higher vessel curvatures, which indicates limited usefulness of high-porosity stents as a stand-alone treatment. Finally, we showed that the stasis-inducing performance of stents in 3D geometries can be predicted from the hydraulic resistance of their flat mesh screens. From this, we propose a methodology to cost-effectively compare different stent designs before running a full 3D simulation.

Neuroform stent-assisted coil embolization of wide-neck intracranial aneurysms: strategies in stent deployment and midterm follow-up

OBJECTIVE

To evaluate the midterm results of intracranial stent-assisted coil embolization in the treatment of wide-necked cerebral aneurysms and to assess the efficacy of various strategies used in stent deployment.

METHODS

A retrospective study of 42 patients with 46 wide-necked cerebral aneurysms enrolled in a prospective single-center registry of patients treated with a Neuroform stent (Boston Scientific/Target, Fremont, CA), a flexible self-expanding nitinol stent, was performed. Twenty-seven of 46 aneurysms were unruptured aneurysms, 14 were recanalized aneurysms, and five were acutely ruptured. Thirty-nine aneurysms were located in the anterior and seven in the posterior circulation. Mean aneurysm size was 9.8 mm. Stenting before coiling was performed in 13 of 45 aneurysms (29%), coiling before stenting in 27 of 45 aneurysms (60%), and stenting alone in five of 45 aneurysms (11%). The balloon remodeling technique for coiling before stenting was performed in 77% of patients. Angiographic and clinical follow up was available in 31 patients with 33 aneurysms and ranged from 3 to 24 months.

RESULTS

Neuroform stenting was attempted in 46 wide-necked aneurysms (42 patients). Forty-nine stent sessions were performed, including three poststent retreatments. In 46 of 49 sessions (94%), successful deployment of 47 stents for 45 aneurysms was obtained. In 40 aneurysms treated with stent-assisted coiling, angiographic results showed 14 (35%) aneurysm occlusions, 18 (45%) neck remnants, and eight (20%) residual aneurysms. In five recanalized aneurysms treated with stenting alone, no changes were observed in four (80%) aneurysms and one (20%) neck remnant reduced in size. At angiographic follow-up in 30 aneurysms treated with stent-assisted coiling, there were 17 (57%) aneurysm occlusions, seven (23%) neck remnants, and six (20%) residual aneurysms. In three recanalized aneurysms treated with stent alone, two (67%) neck remnants remained unchanged and one (33%) neck remnant decreased in size. Procedural morbidity was observed in two of 42 patients (4.8%) and one patient died. On clinical follow-up, the modified Rankin Scale score was 0 in 27 patients (87%), 1 in three patients (10%), and 2 (3%) in one patient. No aneurysm bled during the follow-up period.

CONCLUSION

These results indicate that Neuroform stent-assisted coil embolization is a safe and effective technique in the treatment of wide-necked cerebral aneurysms. Further studies are needed to evaluate the long-term durability of stent-assisted aneurysm occlusion and tolerance to the stent.

Recent steps toward a reconstructive endovascular solution for the orphaned, complex-neck aneurysm

OBJECTIVE

The purposes of this article are to summarize recent developments and concerns in endovascular aneurysm therapy leading to the adjunctive use of endoluminal devices, to review the published literature on stent-supported coil embolization of cerebral aneurysms, and to describe our experience with this technique in a limited subgroup of problematic complex aneurysms over a medium-term follow-up period.

METHODS

Between January 2003 and June 2004, 28 individuals among 157 patients with cerebral aneurysms we evaluated were identified as harboring aneurysms with exceptionally broad necks. Out of these 28 patients, 16 were treated with a combination of stents and detachable coils, preserving the parent artery. Recorded data included patient demographics, the clinical presentation, aneurysm location and characteristics, procedural details, and clinical and angiographic outcome.

RESULTS

Over an 18-month period, 16 patients with large cerebral aneurysms additionally characterized by neck sizes between 7 and 14 mm were treated, using combined coil embolization of the aneurysm with stent reconstruction of the aneurysm neck. Thirteen out of the 16 aneurysms were occluded at angiographic reevaluation between 11 and 24 months (mean angiographic follow-up, 17.5 mo). There were no treatment-related deaths or clinically evident neurological complications. Thirteen patients experienced excellent clinical outcomes, with good outcomes in two patients and a poor visual outcome in one patient (mean clinical follow-up, 29 mo). A single technical complication occurred, involving transient nonocclusive stent-associated thrombus, which was treated uneventfully with abciximab.

CONCLUSION

Stent-supported coil embolization of large, complex-neck cerebral aneurysms seems to provide superior medium-term anatomic reconstruction of the parent artery compared with historic series of aneurysms treated exclusively with endosaccular coils. In the near future, increasingly sophisticated endoluminal devices offering higher coverage of the neck defect will likely enable more definitive endovascular treatment of complex cerebral aneurysms and further expand our ability to manipulate the vascular biology of the parent artery.

Balloon-expandable stenting with and without coiling for wide-neck and complex aneurysms

BACKGROUND

Wide-necked, saccular, dissecting, and fusiform intracranial aneurysms are poor coil retainers. Retention can be improved by parent-artery stenting across the aneurysm.

METHODS

We used a balloon-expandable stent and delivery system, intending to treat 38 aneurysms in 36 patients. Stents could not be advanced across the neck of 2 aneurysms near the ophthalmic artery origin. These cases were managed by temporary balloon remodeling and coiling. Stenting alone was done for 15 aneurysms, including 7 in vertebral artery V4 segments. Stenting with immediate or delayed coiling was done in 21 aneurysms.

RESULTS

Stenting alone caused immediate and complete obliteration of 1 treated aneurysm (7%), subtotal obliteration in 13 treated (86%) aneurysms, and was associated with 1 failure. Stenting and coiling yielded a significantly better 57% complete obliteration rate, 43% subtotal obliteration, and no failures. There were 5 complications: 1 wire perforation, 2 cavernous-carotid-sinus fistulae, and 2 partial in-stent thromboses. All were controlled or cleared with no long-term sequelae or deaths. Contrast imaging at 1 to 12 months was available for 30 patients (13 stent-only, 17 stent-plus-coiling), demonstrating complete obliteration in 25 (83%) and subtotal obliteration in 5. A total of 7 stent-only aneurysms (4 V4s) were completely obliterated, and 3 (all V4s) were > or = 90% obliterated.

CONCLUSION

Stenting and coiling through the wall of the stent resulted in 88% (15/17) complete obliteration when imaged 1 to 12 months after treatment. Stenting alone effectively closed off V4-segment wide-necked aneurysms but was inferior to stenting and coiling in less mobile vessels.

Intrasaccular combination of metallic coils and Onyx liquid embolic agent for the endovascular treatment of cerebral aneurysms

Object

The aim of this study was to report on a novel technique in which metallic embolization coils were combined with the Onyx liquid embolic agent in the aneurysm sac to achieve a more durable result after endovascular treatment. This therapeutic procedure was performed in selected cases in which, based on the authors’ experiences, either coil embolization or Onyx alone would likely have failed. The authors report long-term clinical and angiographic follow-up results in 20 consecutive intracranial aneurysms treated using this combination for defined indications.

Methods

Twenty aneurysms in 20 patients were treated with a combination of embolic coils and Onyx. Four aneurysms were giant; 13, large; and three, small. This new technique was used when standard Onyx or coil treatment with balloon assistance was determined to involve a higher possibility of recanalization, because either an adjunctive stent insertion could not be performed or the Onyx technique could not be used due to an unsuccessful seal test or intraaneurysm balloon prolapse. In one case, an adjunctive stent was placed before coil placement and Onyx deposition to control the material in the sac of the aneurysm, which had a fusiform neck.

All aneurysms were completely occluded after using this technique. No clinical or technical adverse events occurred in any of the cases. Follow-up angiography was performed in all patients: 3-year studies in six patients, 2-year studies in five, and 1-year studies in nine. None of these studies demonstrated aneurysm regrowth or parent artery occlusion.

Conclusions

The combination of the embolic coils and the Onyx liquid embolic agent provides very durable aneurysm occlusion for defined indications.

Giant Intracranial Aneurysms: Endovascular Challenges

THE TREATMENT OF giant aneurysms remains a formidable challenge for endovascular and surgical strategies. The use of endovascular techniques in a deconstructive (e.g., parent vessel occlusion) and reconstructive (e.g., stent coiling) methodology is reviewed. The results of endovascular coiling as a primary therapy for giant aneurysm occlusion have been disappointing. Hunterian strategies have had more success in published series, but recent developments in coil, glue, and stent technology show great promise in allowing parent vessel reconstruction as a primary endovascular target, with acceptable morbidity, mortality, and durability. A literature review of giant aneurysm endovascular treatment strategies was undertaken after 1994, when Guglielmi detachable coils were approved by the Food and Drug Administration. Where possible, follow-up, durability, and occlusion rates are also reviewed.

Long-term histological and scanning electron microscopy results of endovascular and operative treatments of experimentally induced aneurysms in the rabbit

OBJECTIVE

Treatment strategies of cerebral aneurysms include surgical clipping and endovascular therapies. To determine the long-term results of these therapeutic strategies, the vessel wall reaction close to the former aneurysm was studied according to the assumption that an intact endothelial layer over the former aneurysm neck constitutes complete vessel wall reconstruction and stable aneurysm obliteration.

METHODS

Aneurysms were created in 40 rabbits by intraluminal elastase incubation of the common carotid artery. Five animals each were assigned to the following groups: untreated, porous stents, polyurethane covered stentgrafts, porous stents with subsequent coiling. Ten animals were treated with coils alone, 10 with clips. After 6 months, angiography, histology, and scanning electron microscopy was performed.

RESULTS

Porous stents did not obliterate the aneurysm, whereas stentgrafts did; in-stent stenosis of up to 60% was present because of neointimal multilayer proliferation. After coiling, the aneurysm dome was occluded with fibrinous and collagenous material, whereas the aneurysm neck was not covered by an endothelial lining. Coil loops lay bare within the vessel, with fresh thrombus material on their surface. After clipping, a thin layer of endothelial lining bridging the two attached vessel walls was present, thereby completely obliterating the aneurysm and reconstructing the vessel wall.

CONCLUSION

This study demonstrates complete and stable aneurysm obliteration with vessel wall reconstruction after clipping, a sufficient obliteration of the aneurysm dome using endovascular techniques, but a failed healing response of the aneurysm neck that might correlate to its associated higher risk of rebleed. Whether or not this is counterbalanced by the better immediate outcome after endovascular treatment remains a matter of debate.

Endovascular Reconstruction with the Neuroform Stent as Monotherapy for the Treatment of Uncoilable Intradural Pseudoaneurysms

OBJECTIVE:

Intradural pseudoaneurysms have a malignant natural history and can be difficult to treat if parent vessel deconstruction is not feasible. These lesions often involve a long arterial segment and lack a defined saccular component that would safely accommodate the introduction of embolization coils. The current report describes the successful endovascular treatment of these lesions using a strategy of Neuroform stent reconstruction.

METHODS:

A retrospective review of the prospectively maintained Neuroform databases from our two institutions identified all intracranial aneurysms treated with the Neuroform stent alone, without embolization coils. The clinical charts, procedural data, and angiographic results were reviewed.

RESULTS:

Over a 38-month study period (10/02–2/06), 266 aneurysms were treated with the Neuroform stent. Of these, 10 were small “uncoilable” intradural pseudoaneurysms associated with subarachnoid hemorrhage. These lesions were treated using a strategy of endovascular stent reconstruction of the diseased vascular segment with one or more Neuroform stents (without concomitant coil embolization). Seven pseudoaneurysms were treated in the context of acute or subacute subarachnoid hemorrhage, and three were associated with a remote history of subarachnoid hemorrhage. Periprocedural complications occurred in two patients (clinically silent, intraprocedural thromboembolic event successfully treated with intra-arterial abciximab, symptomatic postprocedural stent thrombosis with successful thrombolysis, and excellent neurological recovery). Both complications occurred in patients with ruptured aneurysms and could be attributed to inadequate platelet inhibition at the time of the initial procedure. Follow-up conventional angiographic examinations were available for all 10 patients with pseudoaneurysms (1–18.5 mo; average, 9.0 mo). In nine cases, the aneurysms improved at follow-up, with either complete (n = 5) or near complete (n = 4) resolution. In one case, short-term follow-up (1 mo) demonstrated no significant change. No patient has rehemorrhaged after treatment.

CONCLUSION:

Endovascular Neuroform stent reconstruction represents an optimal strategy for the management of intradural pseudoaneurysms that require a constructive treatment strategy and are too small to accommodate the introduction of embolization coils. Nine out of 10 patients in the current series treated with this strategy demonstrated some degree of endovascular remodeling with either complete (n = 5) or partial (n = 4) angiographic resolution at follow-up. No rehemorrhages were encountered. Adequate antiplatelet therapy, even in the setting of acute subarachnoid hemorrhage, is prerequisite for the avoidance of thromboembolic complications.

Neuroform in-stent stenosis: incidence, natural history, and treatment strategies

OBJECTIVE

Delayed in-stent stenosis is an important and well-characterized complication of angioplasty and stenting for the treatment of intra- and extracranial atheromatous disease. The current series describes the incidence and natural history of in-stent stenosis after the deployment of the Neuroform stent within the cerebrovasculature for the treatment of aneurysms.

METHODS

The collaborative Cleveland Clinic Foundation-Barrow Neurological Institute endovascular database was reviewed to identify cases of delayed moderate or severe in-stent stenosis observed during the follow-up of cerebral aneurysms treated with the Neuroform stent. The hospital charts, clinic records, and operative reports for these patients were reviewed.

RESULTS

Of a total of 156 patients with follow-up, nine (5.8%) cases of moderate or severe delayed (>2 mo) in-stent stenosis were identified, including two parent vessel occlusions. In two cases, patients presented 3 months after stent-supported aneurysm embolization with focal neurological symptoms. Both of these patients were treated with angioplasty. One eventually required surgical bypass. Of the seven asymptomatic patients, four demonstrated some degree of spontaneous resolution at follow-up, one progressed to complete occlusion, one is awaiting further follow-up, and one patient died of unrelated causes. Of the nine patients in the series, five were treated with "bioactive" coils (Matrix, Hydrocoil, Cerecyte), three were treated with bare platinum coils, and one was treated with stenting alone. The earliest time interval to diagnosis was 2.5 months and 3 months for asymptomatic and symptomatic patients, respectively. The earliest interval documented for spontaneous resolution was 9 months.

CONCLUSION

Delayed Neuroform in-stent stenosis, occurring in 5.8% of cases, is not a rare phenomenon. The stenosis can be symptomatic and may require endovascular treatment or surgical bypass. In asymptomatic patients, a strategy of "watchful waiting" may be effective because many patients demonstrate partial or complete resolution at follow-up. The spontaneous resolution of delayed in-stent stenosis has not been previously described. This may be a phenomenon unique to the application of low radial force, self-expanding stents within the nonatheromatous cerebrovasculature.

Exclusion of a cavernous aneurysm by leo stent

SUMMARY

The Leo stent is a cranial self-expanding stent recently developed for the treatment of wideneck aneurysms.We report the first case with total occlusion of a cavernous aneurysm nine months after stent placement without complementary coiling.

Treatment of a middle cerebral artery bifurcation aneurysm using a double neuroform stent "Y" configuration and coil embolization: technical case report

OBJECTIVE AND IMPORTANCE

Wide-necked cerebral aneurysms have been particularly difficult to treat using coil embolization. The introduction of the first intracranial flexible stent (Neuroform stent; Boston Scientific/Target, Fremont, CA) has provided a great advantage to this dilemma by forming a bridge across the aneurysm neck and allowing the packing of coils. Despite this advancement, some parent vessel bifurcation aneurysms can still remain elusive to single stent and coiling technique.

CLINICAL PRESENTATION

A 55-year-old woman presented for a routine follow-up angiogram. Her past history was significant for a subarachnoid hemorrhage and clipping of an anterior communicating aneurysm with full recovery. An incidental new right middle cerebral artery aneurysm was found on the angiogram. We report here a case of an unruptured asymptomatic wide-neck middle cerebral artery bifurcation aneurysm that was treated with a novel endovascular repair.

INTERVENTION

The aneurysm was successfully treated using a double stent "Y" configuration and coil embolization technique using the Neuroform stent. Technical aspects are discussed. Perioperative management issues and potential pitfalls are also considered.

CONCLUSION

Double stenting in "Y" configuration and coiling is feasible. This technique should increase the ability to endovascularly treat wide-necked aneurysms.

Delayed coil migration from a small wide-necked aneurysm after stent-assisted embolization: case report and literature review

INTRODUCTION

We present a previously unreported complication following the treatment of a patient with two small, wide-necked, posterior communicating artery aneurysms.

METHODS

Endovascular embolization of one aneurysm was performed using a stent-assisted technique. Follow-up angiography 5 months later revealed that a coil had escaped the confinement of the stent and migrated distally without occluding any arterial branches or causing symptoms. This case report demonstrates that although a rare occurrence, a coil can break loose from the stent.

DISCUSSION

We discuss the potential mechanisms of this phenomenon and review the literature on stent-assisted aneurysm coiling in order to raise awareness of this event when embolizing small, wide-necked aneurysms with a stent-assisted technique.

Flow modification in canine intracranial aneurysm model by an asymmetric stent: studies using digital subtraction angiography (DSA) and image-based computational fluid dynamics (CFD) analyses

An asymmetric stent with low porosity patch across the intracranial aneurysm neck and high porosity elsewhere is designed to modify the flow to result in thrombogenesis and occlusion of the aneurysm and yet to reduce the possibility of also occluding adjacent perforator vessels. The purposes of this study are to evaluate the flow field induced by an asymmetric stent using both numerical and digital subtraction angiography (DSA) methods and to quantify the flow dynamics of an asymmetric stent in an in vivo aneurysm model. We created a vein-pouch aneurysm model on the canine carotid artery. An asymmetric stent was implanted at the aneurysm, with 25% porosity across the aneurysm neck and 80% porosity elsewhere. The aneurysm geometry, before and after stent implantation, was acquired using cone beam CT and reconstructed for computational fluid dynamics (CFD) analysis. Both steady-state and pulsatile flow conditions using the measured waveforms from the aneurysm model were studied. To reduce computational costs, we modeled the asymmetric stent effect by specifying a pressure drop over the layer across the aneurysm orifice where the low porosity patch was located. From the CFD results, we found the asymmetric stent reduced the inflow into the aneurysm by 51%, and appeared to create a stasis-like environment which favors thrombus formation. The DSA sequences also showed substantial flow reduction into the aneurysm. Asymmetric stents may be a viable image guided intervention for treating intracranial aneurysms with desired flow modification features.

Treatment of vertebro-basilar dissecting aneurysms using intravascular stents

SUMMARY

Endovascular surgery is an established primary therapeutic modality for dissecting aneurysms at vertebro-basilar arteries. Intravascular stents can be used to treat the dissecting aneurysms for which simple obliteration procedures cannot be used. In such cases, stent implantation alone or a combination of stents and coils need to be selected properly by taking into consideration the site and shape of dissections. In this report, three patterns of stent application are described and their method of selection is discussed.

Late angiographic and clinical follow-up results of 100 consecutive aneurysms treated with Onyx reconstruction: largest single-center experience

We present the long-term clinical and angiographic follow-up results of 100 consecutive intracranial aneurysms treated with Onyx liquid embolic system (MTI, Irvine, Calif.), either alone or combined with an adjunctive stent, in a single center. A total of 100 aneurysms in 94 patients were treated with endosaccular Onyx packing. Intracranial stenting was used adjunctively in 25 aneurysms including 19 during initial treatment and 6 during retreatment. All aneurysms except two were located in the internal carotid artery. Of the 100 aneurysms, 35 were giant or large/wide-necked, and 65 were small. Follow-up angiography was performed in all 91 surviving patients (96 aneurysms) at 3 and/or 6 months. Follow-up angiography was performed at 1, 2, 3, 4 and 5 years in 90, 41, 26, 6 and 2 patients, respectively. Overall, aneurysm recanalization was observed in 12 of 96 aneurysms with follow-up angiography (12.5%). All 12 were large or giant aneurysms, resulting in a 36% recanalization rate in the large and giant aneurysm group. One aneurysm out of 25 treated with the combination of a stent and Onyx showed recanalization. There was also no recanalization in the follow-up of small internal carotid artery aneurysms treated with balloon assistance only. At final follow-up, procedure- or device-related permanent neurological morbidity was present in eight patients (8.3%). There were two procedure-related and one disease-related (subarachnoid hemorrhage) deaths (mortality 3.2%). Delayed spontaneous asymptomatic occlusion of the parent vessel occurred in two patients, detected on routine follow-up. Onyx provides durable aneurysm occlusion with parent artery reconstruction resulting in perfectly stable 1-year to 5-year follow-up angiography both in small aneurysms treated with balloon assistance only (0% recanalization rate) and large or giant aneurysms treated with stent and Onyx combination (4% recanalization rate). Endosaccular Onyx packing with balloon assistance may not be adequate for stable long-term results in those with a large or giant aneurysm. However, the recanalization rate of 36% in these aneurysms is better than the reported results with other techniques, i.e., coils with or without adjunctive bare stents.

A proposed parent vessel geometry-based categorization of saccular intracranial aneurysms: computational flow dynamics analysis of the risk factors for lesion rupture

OBJECT

The authors created a simple, broadly applicable classification of saccular intracranial aneurysms into three categories: sidewall (SW), sidewall with branching vessel (SWBV), and endwall (EW) according to the angiographically documented patterns of their parent arteries. Using computational flow dynamics analysis (CFDA) of simple models representing the three aneurysm categories, the authors analyzed geometry-related risk factors such as neck width, parent artery curvature, and angulation of the branching vessels.

METHODS

The authors performed CFDAs of 68 aneurysmal geometric formations documented on angiograms that had been obtained in patients with 45 ruptured and 23 unruptured lesions. In successfully studied CFDA cases, the wall shear stress, blood velocity, and pressure maps were examined and correlated with aneurysm rupture points. Statistical analysis of the cases involving aneurysm rupture revealed a statistically significant correlation between aneurysm depth and both neck size (p < 0.0001) and caliber of draining arteries (p < 0.0001). Wider-necked aneurysms or those with wider-caliber draining vessels were found to be high-flow lesions that tended to rupture at larger sizes. Smaller-necked aneurysms or those with smaller-caliber draining vessels were found to be low-flow lesions that tended to rupture at smaller sizes. The incidence of ruptured aneurysms with an aspect ratio (depth/neck) exceeding 1.6 was 100% in the SW and SWBV categories, whereas the incidence was only 28.75% for the EW aneurysms.

CONCLUSIONS

The application of standardized categories enables the comparison of results for various aneurysms' geometric formations, thus assisting in their management. The proposed classification system may provide a promising means of understanding the natural history of saccular intracranial aneurysms.

Middle cerebral artery stenosis: endovascular and surgical options

Atherosclerotic middle cerebral artery stenosis is a rare but potentially devastating cause of cerebral ischemia and stroke. While medical management remains the mainstay for stroke prevention, surgical and/or endovascular intervention is indicated in selected patients. This article reviews the role of surgery and endovascular techniques in the treatment of middle cerebral artery stenosis based on its natural history, pathophysiology, and prognosis when treated medically.

Endovascular Management of a Patient after SAH

Treatment of acute aneurysmal subarachnoid hemorrhages consists of occluding the aneurysm to prevent rebleed, attempting to prevent vasospasm, and maintaining blood flow to the brain through vessels in vasospasm. Endovascular treatment has been shown to be as safe as, or safer, than surgical clipping for patients with SAH. Engineering solutions to our clinical problems continue to improve endovascular outcomes. This article reviews the current state of endovascular therapy.

Intensive care unit management of interventional neuroradiology patients

The management of interventional neurologic patients in the intensive care unit is based on their underlying disease for the most part. Patients with ischemic stroke are largely managed like patients with ischemic stroke who have not undergone interventional procedures, and the same is true for those with an aneurysmal subarachnoid hemorrhage or intracerebral hemorrhage secondary to an arteriovenous malformation, for example.Having said this, there are some special considerations that require special mention when it comes to managing patients after catheter-based procedures.