Faculty Bibliography

INTRODUCTION/BACKGROUND:The glial-lymphatic pathway is a fluid-clearance pathway consisting of a para-arterial route for the flow of cerebrospinal fluid along perivascular spaces and subsequently toward the brain interstitium. In this case series we aim to investigate an empirical demonstration of glymphatic clearance of extravasated iodine following perforation incurred during endovascular therapy on serial CT. METHODS AND RESULTS/RESULTS:Six consecutive cases of endovascular perforation during thrombectomy performed between 2005 and 2018 were retrospectively collected by searching our internal database of total 446 thrombectomies. Two cases were excluded because care was withdrawn shortly following the procedure and no follow-up imaging was available. One case was excluded because a ventricular drain was placed. Three cases were hence included in this analysis. All three cases demonstrated progressive absorption of contrast by the brain parenchyma with eventual contrast disappearance. CONCLUSION/CONCLUSIONS:We described a likely in vivo CT correlate of the glymphatic system in a cohort of patients who sustained intraprocedural extravasation during thrombectomy for acute ischemic stroke.

Flow diverters (FDs) have changed the management of brain aneurysms; not only for complex aneurysms (giant, fusiform and blister) refractory to conventional therapies, but also for unruptured lesions previously managed by traditional surgical or coil-based endovascular methods. Since 2011 when the PipelineTM Embolization Device (Medtronic) was cleared by the Food and Drug Administration for adults with large or giant wide-neck intracranial aneurysms of the internal carotid artery proximal to the posterior communicating segment, the role of flow diversion for aneurysm treatment has expanded-supported by favorably low complication and high cure rates compared with alternative treatments. Here we review the key clinical trials and the long term outcomes that have demonstrated safety and efficacy of minimized porosity endoluminal devices in the treatment of cerebral aneurysms.

OBJECTIVE:Cavernous carotid fistulas (CCF) are anatomically complex vascular lesions. Treatment via the venous approach has been previously described and is highly dependent on the patency of the drainage pathways. The use of a unilateral approach to contralateral or bilateral shunts is technically challenging and not commonly described. We present our experience with the unilateral across-the-midline approach to both cavernous sinuses to treat shunts according to anatomical compartments to achieve anatomical cure. METHODS:Patients included in this study presented with either bilateral or unilateral shunts with unilateral venous drainage. We used a trans-arterial guiding catheter for road mapping and control angiography. A venous tri-axial system was used to achieve support for distal navigation across the midline via the coronary sinus to the contralateral cavernous sinus. Coils were favored for embolization with occasional complementary liquid embolic material. RESULTS:Five patients underwent complete occlusion in a single session. One patient required additional complimentary trans-arterial embolization. Despite a successful unilateral approach to bilateral cavernous sinuses, one patient needed an additional ipsilateral trans-ophthalmic vein approach to obliterate the anterior compartment of the cavernous sinus. No complications were encountered. Complete angiographic cure was observed in all patients by the end of the final procedures, with persistent occlusion in their follow up imaging. CONCLUSION/CONCLUSIONS:Careful inspection of the venous anatomy and fistulization sites is critical when treating unilateral or bilateral Carotid Cavernous shunts. The contralateral venous route can serve as a safe approach when visualized. Crossing the midline via the anterior or posterior coronary sinuses is feasible and efficacious.

PURPOSE/OBJECTIVE:To develop a preclinical model of stroke with a large vessel occlusion treated with mechanical thrombectomy. MATERIALS AND METHODS/METHODS:An ischemic stroke model was created in dogs by the introduction of an autologous clot into the middle cerebral artery (MCA). A microcatheter was navigated to the clot and a stent retriever thrombectomy was performed with the goal to achieve Thrombolysis in Cerebral Ischemia (TICI) 2b/3 reperfusion. Perfusion and diffusion MRI was acquired after clot placement and following thrombectomy to monitor the progression of restricted diffusion as well as changes in ischemia as a result of mechanical thrombectomy. Post-mortem histology was done to confirm MCA territory infarct volume. RESULTS:Initial MCA occlusion with TICI 0 flow was documented in all six hound-cross dogs entered into the study. TICI 2b/3 revascularization was achieved with one thrombectomy pass in four of six animals (67%). Intra-procedural events including clot autolysis leading to spontaneous revascularization (n=1) and unresolved vasospasm (n=1) accounted for thrombectomy failure. In one case, iatrogenic trauma during microcatheter navigation resulted in a direct arteriovenous fistula at the level of the cavernous carotid. Analysis of MRI indicated that a volume of tissue from the initial perfusion deficit was spared with reperfusion following thrombectomy, and there was also a volume of tissue that infarcted between MRI and ultimate recanalization. CONCLUSION/CONCLUSIONS:We describe a large animal stroke model in which mechanical thrombectomy can be performed. This model may facilitate, in a preclinical setting, optimization of complex multimodal stroke treatment paradigms for clinical translation.

BACKGROUND:The treatment of selected wide-neck and fusiform posterior circulation aneurysms is challenging for clipping as well as for endovascular route. OBJECTIVE:To describe an endovascular approach for vertebral artery aneurysm treatment using transradial access (TRA) instead of the conventional transfemoral access. METHODS:We collected cases from two institutions in which TRA was used for posterior circulation Pipeline Embolization Device (Medtronic, Dublin, Ireland) deployment. RESULTS:A total of four patients were treated. TRA was useful in the setting of extreme vessel tortuosity. We utilized 5F Terumo Glidesheath (Terumo Medical, Somerset, New Jersey), intermediate catheter, and a 027 microcatheter for Pipeline deployment. TRA was not associated with any access or deployment difficulties. CONCLUSIONS:Early experience suggests that TRA for Pipeline Embolization Device placement for posterior circulation aneurysm is a safe and efficient alternative to standard transfemoral access. While this approach was initially applied to patients with vascular anatomy that may not allow for safe femoral access or navigation, experience so far argues for considering a radial approach towards some posterior circulation aneurysm treatment.

BACKGROUND:Cerebral bypass operation is a technically challenging operation that requires excellent surgical visibility and efficient ergonomics to minimize complications and maximize successful revascularization. Despite the operative microscope's utilization for the past two generations, there remains a need for continued improvement in operative visualization and surgical ergonomics. OBJECTIVE:To report the positives and negatives of our initial experience using a novel 4 K high-definition (4K-HD) 3-dimensional (3D) exoscope (EX) for cranial bypass surgery. METHODS:A retrospective review over 6 mo was performed of all patients who have undergone cerebral bypass surgery at a single institution using the 4K-HD 3D EX. Advantages and disadvantages of the EX and clinical outcome of the patients were assessed. RESULTS:A total of 5 patients underwent cerebral EC-IC bypass surgery with no EX-related complications and successful revascularization. The lightweight design of the EX allowed for easy instrument maneuverability as well as uncomplicated surgical set up in the operating room. The assistance of the cosurgeon was significantly more efficient compared to that of the operating microscope. The large monitor allowed for an immersive, collaborative, and valuable educational surgical experience. CONCLUSION/CONCLUSIONS:Using the EX for cerebral bypass surgery, with 3D ultra-high-definition optics, enhancements of ergonomics, and improved training, we believe that the 3D 4K-HD EX may represent the next generation of operative scopes in microneurosurgery.

BACKGROUND:Colloid cysts (CC) have been associated with neurocognitive function (NCF) decline, both preoperatively and following resection. Factors such as local pressure on the fornix and hydrocephalus are thought to contribute to preoperative NCF decline. Potential cause of post-operative decline is thought to be forniceal injury during surgery. In the current series, we describe NCF outcomes amongst patients with CC, both non-operated and operated. METHODS:36 patients (23 operated, 13 non-operated) were included in this retrospective study. All patients underwent at least one NCF evaluation battery. Five of the 13 non-operated cases had follow up tests too. Of the 23 operated, 14 had both pre-and post-operative tests, 8 had early and late postoperative tests. RESULTS:There was no significant difference in baseline NCF between non-operated and operated cases (as evaluated preoperatively). Non-operated patients had a stable NCF test over time. Patients that were operated showed a significant improvement after surgery in several NCF variables. There was no significant change in NCF between early and late postoperative evaluation. None of the operated patients had a postoperative NCF decline. CONCLUSIONS:Patients with CC should undergo routine NCF testing with a standardized protocol, whether they are operated or followed. Surgery has a positive impact on NCF; however, it remains to be determined if the improvement is solely secondary to treatment of hydrocephalus, or to a reduction of local pressure on the fornices. It remains to be determined whether the surgical technique - i.e. endoscopic, interhemispheric, or transcortical, has an impact on NCF outcome.