Richard J. Parkinson

The effect of vascular reconstruction device-assisted coiling on packing density, effective neck coverage, and angiographic outcome: an in vitro study.

OBJECTIVEThe objective of this study was to assess the variations in packing density, effective neck coverage, and angiographic outcome between aneurysm coiling alone and with the support of the Enterprise Vascular Reconstruction Device (VRD; Cordis Neurovascular, Inc., Miami Lakes, FL). Although the use of VRD-assisted coiling is growing due to the availability of better devices, little is known about the impact of the VRDs on the aforesaid variables. METHODSTen groups of two silicone aneurysm models each were embolized with detachable coils, one with VRD support and one without. Coil embolization ceased once the microcatheter backed out of the aneurysm or there was a risk that further packing would lead to coil herniation. Angiograms were assessed using the Raymond classification scale. Gross macroscopic images of the aneurysm neck were taken to quantify the coil neck coverage, defined as the surface area fraction of coils at the neck divided by the total neck area. Packing density was calculated. RESULTSPacking density significantly increased with VRD assistance (absolute increase, 10.5%; relative increase, 31%; P < 0.0001, paired t test). Effective neck coverage significantly increased by 9% with VRD deployment (P < 0.05, t test). Angiographically, aneurysms coiled without VRD support were more likely to have a dome remnant (P < 0.05, Fishers exact test) and coil prolapse into the parent vessel. CONCLUSIONVRD deployment improves coil neck coverage and increases packing density. These results support the hypothesis that VRD deployment to reinforce coil embolization of cerebral aneurysms may lead to more durable aneurysm obliteration.

Chemical meningitis after cerebral aneurysm treatment using two second-generation aneurysm coils: Report of two cases

OBJECTIVE AND IMPORTANCE Dolichoectatic vertebrobasilar artery aneurysms are often extremely difficult, if not impossible, to treat with microneurosurgical clip reconstruction. As such, a Hunterian strategy via vertebral or basilar artery sacrifice is often used. We have encountered a patient in whom deliberate bilateral vertebral artery sacrifice was insufficient to avoid progressive expansion of a giant dolichoectatic vertebrobasilar artery aneurysm. On the basis of a review of the literature, we are unaware of another reported case. CLINICAL PRESENTATION A 60-year-old man presented with signs and symptoms of brainstem compression from a large fusiform aneurysm involving the distal dominant vertebral and proximal basilar arteries. Results of angiographic evaluation were highly characteristic of underlying dolichoectasia. INTERVENTION The patient was treated initially with staged bilateral vertebral artery occlusion and adjunctive posterior circulation revascularization. After this therapy failed, he underwent a trapping procedure and aneurysm deflation. CONCLUSION Unclippable aneurysms of the vertebrobasilar system are formidable lesions. They are not uniformly treatable by direct surgical reconstruction, and their growth is not consistently stabilized by the implementation of a complete Hunterian strategy. Future developments related to the use of endovascular stent technology may offer a more successful treatment approach for patients with these complex cerebrovascular lesions.OBJECTIVE AND IMPORTANCE: In the quest for effective and durable endovascular aneurysm treatment, second-generation aneurysm coils endeavor to increase the biological healing response to the implanted material. We report two cases of large cerebral aneurysms treated concurrently with both available second-generation aneurysm coils and the subsequent development of symptomatic nonbacterial meningitis. CLINICAL PRESENTATION: Two previously healthy patients underwent endovascular treatment for large (≥2 cm) cerebral aneurysms. Both aneurysms were treated using multiple Hydrogel coils (MicroVention, Inc., Aliso Viejo, CA) and Matrix coils (Boston Scientific/Target, Fremont, CA). Careful aseptic technique was observed throughout each procedure, and prophylactic intravenous antibiotics were administered during the perioperative period to both patients. Treatment proceeded uneventfully in both cases with excellent aneurysm occlusion and no immediate postoperative neurological deficits. INTERVENTION: In both cases, the patients were discharged from hospital but quickly were readmitted with stigmata of meningitis. Imaging demonstrated durable occlusion of the aneurysms in both patients and also abnormalities indicative of perianeurysmal and diffuse intracranial inflammatory response. Complete septic workup failed to identify an organism in either patient. Both patients responded to treatment with corticosteroid medication used to modulate the inflammatory response induced by the coil implants. CONCLUSION: Second-generation aneurysm coils were developed to promote more durable occlusion of cerebral aneurysms by promoting more complete volumetric aneurysm occlusion or by eliciting a more prolific inflammatory response. The concurrent use of Hydrogel and Matrix coil systems in large aneurysms may cause an exuberant inflammatory response with both local and systemic manifestations. Although vigilant evaluation and treatment for presumptive bacterial meningitis is required in all such cases, patients respond to immunomodulatory therapy with corticosteroids. More information to understand better the interaction of Hydrogel and Matrix coils is needed.

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.

Functional Magnetic Resonance Imaging and Optical Imaging for Dominant-hemisphere Perisylvian Arteriovenous Malformations

OBJECTIVE:In this study, we developed an a priori system to stratify surgical intervention of perisylvian arteriovenous malformations (AVMs) in 20 patients. We stratified the patients into three categories based on preoperative functional magnetic resonance imaging (fMRI) language activation pattern and relative location of the AVM. METHODS:In Group I (minimal risk), the AVM was at least one gyrus removed from language activation, and patients subsequently underwent asleep resection. In Group II (high risk), the AVM and language activation were intimately associated. Because the risk of postoperative language deficit was high, these patients were then referred to radiosurgery. In Group III (indeterminate risk), the AVM and language were adjacent to each other. The risk of language deficit could not be predicted on the basis of the fMRI alone. These patients underwent awake craniotomy with electrocortical stimulation mapping and optical imaging of intrinsic signals for language mapping. RESULTS:All patients from Group I (minimal risk) underwent asleep resection without deficit. All Group II (high-risk) patients tolerated radiosurgery without complication. In Group III (indeterminate risk), three patients underwent successful resection, whereas two underwent aborted resection after intracranial mapping. CONCLUSION:We advocate the use of fMRI to assist in the preoperative determination of operability by asleep versus awake craniotomy versus radiosurgery referral. In addition, we advocate the use of all three functional mapping (fMRI, electrocortical stimulation mapping, and optical imaging of intrinsic signals) techniques to clarify the eloquence score of the Spetzler-Martin system before definitive treatment (anesthetized resection versus radiosurgery versus intraoperative resection versus intraoperative closure and radiosurgery referral).

Neuroendovascular interventions for intracranial posterior circulation disease via the transradial approach: technical case report

OBJECTIVE AND IMPORTANCE:To describe our experience with the transradial approach for posterior circulation neurointerventional procedures. To the best of our knowledge, this approach has not been described previously for intracranial neuroendovascular procedures. CLINICAL PRESENTATION:The clinical and imaging characteristics as well as periprocedural outcomes of patients treated for intracranial posterior circulation disease via the transradial approach were analyzed retrospectively. INTERVENTION:Between January 1 and October 21, 2003, four patients with posterior circulation disease (aneurysm, n = 1, and atherosclerotic stenosis, n = 3) were treated via the transradial approach because of tortuous brachiocephalic anatomy. Procedural success was 100%, and there were no procedural complications. No technical difficulties were encountered. CONCLUSION:The transradial approach is an alternative to the femoral approach for posterior circulation neuroendovascular intervention. This approach has several advantages over other approaches, and the vasculature can be less tortuous than that encountered during the femoral approach. These factors can result in increased device trackability and procedural ease.

Methods and Design Considerations for Randomized Clinical Trials Evaluating Surgical or Endovascular Treatments for Cerebrovascular Diseases

OBJECTIVEThe results of clinical trials affect the practice of surgery and endovascular therapy for cerebrovascular diseases. The purpose of this report is to review the basic components of the designs and methods for randomized clinical trials and to describe the influence of those components on the interpretation of trial results. METHODSThe goal of an optimal clinical trial of a new procedure is to provide the most objective and rigorous evaluation of the safety and effectiveness of that procedure. Anything in the design, performance, or analysis that impairs such an assessment decreases the ability of the trial to achieve its goal and answer the research question. To highlight the components of a clinical trial, this report uses examples of Phase III clinical trials that have influenced the practice of cerebrovascular surgery and endovascular therapy in the past three decades, including the International Cooperative Study of Extracranial/Intracranial Arterial Anastomosis, the North American Symptomatic Carotid Endarterectomy Trial, the Asymptomatic Carotid Atherosclerosis Study, the Prolyse in Acute Cerebral Thromboembolism II study, and the International Subarachnoid Aneurysm Trial. RESULTSThe research question (objective) of the trial must be clearly defined, with an objective measure of efficacy and a specified quantitative difference to define the superiority of one intervention over another, in a relatively homogeneous patient population. Allocation concealment, randomization with or without stratification, and blinding (or masking) are important strategies to prevent differences in the study populations that could adversely affect the conclusions of the study. The primary end point must correspond to the specific aims of the trial. It should be objectively defined, quantifiable, reliable, and reproducible. Commonly defined end points in surgical trials include changes from baseline illness or disease severity scores, morbidity and mortality rates, and relative risks of reaching an end point with time. The statistical methods used for interim and final analyses are important. The effects of dropouts, crossovers, and missing data should be understood in the context of the final analysis. Additional concepts, such as intention-to-treat analysis and use of actual versus predicted outcomes, are important with respect to interpretation of the final results of the study. CONCLUSIONThe neurosurgical and neuroendovascular communities are currently planning or conducting several clinical trials to evaluate new procedures for the treatment of cerebrovascular diseases. It is hoped that a better understanding of the components of clinical trials will facilitate the design and implementation of effective studies.

Coil embolization of posttraumatic pseudoaneurysm of the ophthalmic artery causing subarachnoid hemorrhage : Case report

The authors report a unique case of subarachnoid hemorrhage caused by a traumatic pseudoaneurysm of the ophthalmic artery, which was successfully treated with coil embolization. Clinical and imaging features, as well as the relevant literature, are described.

Balloon Test Occlusion of the Internal Carotid Artery

History Therapeutic sacrifice of the carotid artery (CA) remains an important therapy for many vascular disorders (Table 1). In the 18th century, Hunter was the first person to introduce the concept of initial proximal ligation for the treatment of a peripheral aneurysm. Hunter ligated the feeding vessel to a popliteal aneurysm, thereby reducing the pressure head into the lesion and allowing the distal circulation to be supplied by collateral flow. CA ligation first was performed in 1778 by Abernathy, who used it to control trauma-related hemorrhage. In 1805, Cooper performed the first “elective” carotid occlusion. Both of those procedures were performed for the treatment of patients with cervical carotid aneurysms. In 1902, Horsley also performed a successful common carotid ligation for a patient with an intracranial aneurysm. In 1938, Jefferson reported that internal CA ligation was, with few exceptions, the only useful treatment for patients with aneurysms. From the time it was first advocated, CA ligation carried significant risks. Although most patients can tolerate the loss

Brain Arteriovenous Malformations: Current Endovascular Strategies

General Aspects The management of arteriovenous malformations (AVMs) has evolved significantly in the past two decades. The main goal of AVM treatment is to achieve a permanent cure with minimal morbidity or mortality to the patient, eliminating the risk of bleeding and all related symptoms such as seizures and neurologic deficits. The available methods of treatment include surgical resection with microsurgical techniques, radiosurgery, endovascular treatment with embolization, or a combination of these techniques. Understanding the natural history of this disease has improved and helped to guide decisions regarding treatment strategies. Combined with the increased number of therapeutic options, this has resulted in improved clinical outcomes. Despite advances in radiosurgery and endovascular techniques, surgical resection continues to play an important role in the management of brain AVMs. The most obvious advantage is that it affords immediate cure, but its more invasive nature compared with other options does entail certain risks. Radiosurgery, performed either alone or with endovascular embolization, has made possible the safe and effective treatment of some brain AVMs without the need for craniotomy, but it does carry the risk of radiation injury to adjacent normal tissue and delayed onset of cure. Although a detailed discussion regarding microsurgical resection and radiosurgery for treatment of brain AVMs is beyond the scope of this article, the reader should be aware that all treatment modalities have important roles in the management of this disease. Endovascular embolization techniques have evolved significantly in recent years. Luessenhop, who was the first to report endovascular embolization of a brain AVM, in 1960, injected pellets measuring a few millimeters in diameter and saline through a large catheter positioned in the cervical internal carotid artery that gave rise to the branches supplying the brain AVM, thus reducing its flow. Angiographic equipment has improved since that time so that images of better quality can be obtained, with flow-guided and guidewire-directed microcatheters and microwires enabling Brain Arteriovenous Malformations: Current Endovascular Strategies

Surgical Management of Intracranial Aneurysms Involving the Posteroinferior Cerebellar Artery

Learning Objectives: After reading this article, the participant should be able to:Describe the anatomy of the vertebral and posteroinferior cerebellar arteries.Describe the types of aneurysms involving the posteroinferior cerebellar artery and operative approaches to treatment.List the cerebral revascularization strategies available for complex lesion and the spectrum of postoperative complications after surgical treatment.