Jeffrey S. Pannell

Endothelial Trauma From Mechanical Thrombectomy in Acute Stroke: In Vitro Live-Cell Platform With Animal Validation

Background and Purpose— Endovascular thrombectomy has shown promise for the treatment of acute strokes resulting from large-vessel occlusion. Reperfusion-related injury may contribute to the observed decoupling of angiographic and clinical outcomes. Iatrogenic disruption of the endothelium during thrombectomy is potentially a key mediator of this process that requires further study. Methods— An in vitro live-cell platform was developed to study the effect of various commercially available endovascular devices on the endothelium. In vivo validation was performed using porcine subjects. Results— This novel in vitro platform permitted high-resolution quantification and characterization of the pattern and timing of endothelial-cell injury among endovascular thrombectomy devices and vessel diameters. Thrombectomy devices displayed heterogeneous effects on the endothelium; the device performance assessed in vitro was substantiated by in vivo findings. Conclusions— In vitro live-cell artificial vessel modeling enables a detailed study of the endothelium after thrombectomy and may contribute to future device design. Large animal studies confirm the relevance of this in vitro system to investigate endothelial physiology. This artificial vessel model may represent a practical, scalable, and physiologically relevant system to assess new endovascular technologies.

Minimally invasive treatment of intracerebral hemorrhage

Intracerebral hemorrhages (ICH) cause high levels of morbidity and mortality. Secondary neuronal injury from perihematomal edema is thought to contribute to poor outcomes. Surgical evacuation of ICH is a theoretically promising approach, yet clinical data on the efficacy of standard craniotomy approaches is limited. Recent exploration of minimally invasive techniques for ICH removal includes stereotactic surgery combined with intra-clot thrombolysis, as well as endoscopic hematoma evacuation. Ongoing trials have demonstrated the safety of such minimally invasive approaches, and pending efficacy data from these studies is likely to change the standard management of ICH.

302 Vessel Wall Enhancement on Magnetic Resonance Imaging After Stent-Retriever Thrombectomy.

INTRODUCTION Animal and in vitro studies have demonstrated histologic iatrogenic endothelial injury after stent-retriever thrombectomy. However, noncontrast vessel wall magnetic resonance imaging (MRI) studies have failed to demonstrate vessel injury. Our prospective study examines iatrogenic endothelial damage after stent-retriever thrombectomy in vivo utilizing high-resolution contrast-enhanced vessel wall MRI (VW-MRI). METHODS We evaluated 11 patients, including postthrombectomy and control subjects, on a Signa HDx 3.0-T MRI scanner with an 8-channel head coil. Pre- and postcontrast T1-weighted CUBE vessel wall images and MR angiograms were acquired with attention to the Circle of Willis. Parenchymal imaging included diffusion, susceptibility, and T2 fluid attenuated inversion recovery (FLAIR)-weighted images. The primary end point was vessel wall enhancement, as determined by 2 independent, blinded board-certified neuroradiologists before examination of parenchymal imaging. Additional covariates were age, National Institutes of Health Stroke Scale, level of occlusion, stroke etiology, devices utilized, number of passes required for thrombectomy, TICI reperfusion score, stroke volume, and 90-day modified Rankin Scale (mRS). RESULTS Post-contrast T1-weighted vessel wall enhancement was detected in the middle cerebral artery (MCA) M2 segment in 100%, the M1 segment in 83%, and the internal carotid artery in 50% of thrombectomy patients. One patient demonstrated A1 segment anterior cerebral artery (ACA) enhancement, and was prospectively identified by both radiologists as having undergone ACA thrombectomy due to embolism during MCA thrombectomy. Postcontrast T1-weighted vessel wall enhancement was detected in 0% of control patients. CONCLUSION Our findings suggest that vessel wall injuries incurred during stent-retriever thrombectomy can be detected utilizing contrast-enhanced 3 T VW-MRI. Our results further demonstrate greater endothelial injury when the thrombectomy device is oversized relative to the target vessel. Further studies are needed to evaluate the clinical significance of endothelial injury and differential effects of the device employed.

Hemorrhagic intramedullary solitary fibrous tumor of the conus medullaris: case report

The differential diagnosis of spinal tumors is guided by anatomical location and imaging characteristics. Diagnosis of rare tumors is made challenging by abnormal features. The authors present the case of a 47-year-old woman who presented with progressive subacute right lower-extremity weakness and numbness of the right thigh. Physical examination further revealed an extensor response to plantar reflex on the right and hyporeflexia of the right Achilles and patellar reflexes. Magnetic resonance imaging of the lumbar spine demonstrated an 8-mm intramedullary exophytic nodule protruding into a hematoma within the conus medullaris. Spinal angiography was performed to rule out an arteriovenous malformation, and resection with hematoma evacuation was completed. Pathological examination of the resected mass demonstrated a spindle cell neoplasm with dense bundles of collagen. Special immunostaining was performed and a diagnosis of solitary fibrous tumor (SFT) was made. SFTs are mesenchymally derived pleural neoplasms, which rarely present at other locations of the body, but have been increasingly described to occur as primary neoplasms of the spine and CNS. The authors believe that this case is unique in its rare location at the level of the conus, and also that this is the first report of a hemorrhagic SFT in the spine. Therefore, with this report the authors add to the literature the fact that this variant of an increasingly understood but heterogeneous tumor can occur, and therefore should be considered in the differential of clinically similar tumors.

Endovascular and surgical options for ruptured middle cerebral artery aneurysms: review of the literature.

Middle cerebral artery (MCA) aneurysms are common entities, and those of the bifurcation are the most frequently encountered sublocation of MCA aneurysm. MCA bifurcation (MBIF) aneurysms commonly present with subarachnoid hemorrhage (SAH), are devastating, and are often lethal. At the present time, the treatment of ruptured MBIF aneurysms entails either endovascular or open microneurosurgical methods to permanently secure the aneurysm(s). The purpose of this report is to review the current available data regarding the relative superiority of endovascular versus open microneurosurgical clipping for the treatment of ruptured middle cerebral artery bifurcation aneurysms.

Mycotic Cerebral Aneurysms

Abstract Mycotic intracranial aneurysms are rare neurosurgical sequelae of embolic intravascular infections or a direct spread from adjacent infections. Given the high morbidity associated with this disease process, prompt diagnosis and appropriate management are essential. This chapter reviews the existing literature to discuss presentation, diagnosis, and treatment strategies to optimize outcomes in patients with mycotic aneurysms.

Comprehensive Endovascular and Open Surgical Management of Cerebral Arteriovenous Malformations

Arteriovenious malformations (AVMs) are associated with significant morbidity and mortality, and have a rupture risk of ~3% per year. Treatment of AVMs must be tailored specifically to the lesion, with surgical resection being the gold standard for small, accessible lesions. Pre-operative embolization of AVMs can reduce nidal blood flow and remove high-risk AVM features such as intranidal or venous aneurysms, thereby simplifying a challenging neurosurgical procedure. Herein, we describe our approach for the staged endovascular embolization and open resection of AVMs, and highlight the advantages of having a comprehensively trained neurovascular surgeon leading a multi-disciplinary clinical team. This includes planning the craniotomy and resection to immediately follow the final embolization stage, thereby using a single session of anesthesia for aggressive embolization, and rapid resection. Finally, we provide a representative case of a 22-year-old female with an unruptured right frontal AVM diagnosed during a seizure workup, who was successfully treated via staged embolizations followed by open surgical resection.

ACR Appropriateness Criteria® Cranial Neuropathy

Evaluation of cranial neuropathy can be complex given the different pathway of each cranial nerve as well as the associated anatomic landmarks. Radiological evaluation requires imaging of the entire course of the nerve from its nucleus to the end organ. MRI is the modality of choice with CT playing a complementary role, particularly in the evaluation of the bone anatomy. Since neoplastic and inflammatory lesions are prevalent on the differential diagnosis, contrast enhanced studies are preferred when possible. The American College of Radiology Appropriateness Criteria are evidencebased guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Controversies in Vascular Neurosurgery: Aneurysm Remnants

The low prevalence but serious disability caused by hemorrhage of an incompletely occluded aneurysm understandably creates dispute regarding the proper management of these aneurysms. As mentioned in the previous sections, both aggressive and conservative management are feasible. The risks of retreatment and the risk of repeat hemorrhage both have to be carefully evaluated when deciding between aggressive treatment strategies and observation.