Faculty Bibliography

BACKGROUND Ruptured intracranial aneurysms are associated with a high risk of permanent neurological impairment or death. Evidence suggests that detachable coils can be used to treat ruptured aneurysms safely and effectively; however, data regarding their long-term efficacy is sparse. OBJECTIVE To determine the frequency of late rebleeding of ruptured intracranial aneurysms after treatment with detachable coils. DESIGN AND INTERVENTION In this retrospective study that was conducted over 8 years, 393 consecutive patients (70% female, 30% male) with a ruptured aneurysm were treated with a detachable coil and followed up to determine the incidence of late rebleeding-defined as recurrent hemorrhage from a coiled aneurysm >1 month after coiling. Using angiography, treatment outcomes were classified as complete occlusion (98-100%), near-complete occlusion (90-98%) or incomplete occlusion (<90%). Patients were followed up clinically 6 weeks after initial discharge, and underwent angiographic follow-up at 6 months and 18 months. Further appropriate treatment was undertaken if incomplete occlusion was discovered at any time during the follow-up period. At the time of initial coiling, the mean patient age was 52.9 years (range 2581 years). In total, 63% of patients were classified as Hunt and Hess (HH) Stroke Scale I-II, 21% were HH III and 16% were HH IV-V. The majority of treated ruptured aneurysms were located in the anterior communicating artery (n = 123), the basilar tip (n = 85) or the posterior communicating artery (n = 68). OUTCOME MEASURES The primary outcome was the number of patients to experience late rebleeding after coiling of a ruptured aneurysm. A secondary outcome was the number of patients to require follow-up treatment for aneurysms. RESULTS Clinical data was available for 392 of the 393 patients. The total follow-up duration was 18,708 months, or 1,559 patient-years (mean 47.7 months, range 0-120 months). During follow-up, 70 patients (17.8%) died; deaths were attributed to various factors including subarachnoid hemorrhage (n=23), unrelated causes (n=21) and procedural complications of coiling (n = 11). Mortality associated with late rebleeding was 0.76% (n=3), giving an annual late-rebleeding mortality rate of 0.19% (95% Cl 0.04-0.60%). The late-rebleeding incidence was 1.27% (n=5), giving an annual late-rebleed rate of 0.32% (95% Cl 0.12-0.78%). The median size of the original aneurysm in patients with late rebleeding was 17 mm, compared with 8 mm in patients without late rebleeding (P=0.0017). Late rebleeding occurred in 3 of 366 (0.82%) patients with complete initial aneurysm occlusion, and 2 of 27 patients (7.41%) with incomplete initial occlusion (P=0.04). Additional treatment was required for 53 (13%) coiled aneurysms during the follow-up period. There was no significant difference in the median ages and gender ratios between patients who experienced late rebleeding and those who did not. CONCLUSION Coiling of ruptured aneurysms is associated with a very low rate of rebleeding. Angiographic follow-up reveals incomplete initial occluded aneurysms that might require additional treatment

OBJECTIVE: To examine the relationship between the degree of handedness and hemispheric language dominance in patients with epilepsy. METHODS: The authors examined the relationship between degree of handedness and hemispheric language dominance in 174 epilepsy surgery candidates using the intracarotid amobarbital procedure and results from a modified version of the Edinburgh Handedness Inventory. RESULTS: The incidence of atypical language dominance increased linearly with the degree of left-handedness, from 9% in strong right-handers (laterality quotient [LQ] = +100) to 46% in ambidextrous individuals and 69% in strong left-handers (LQ = -100). CONCLUSIONS: The incidence of atypical language dominance depends not only on the direction but also on the degree of handedness. In addition, direction of language dominance varies with hemisphere of seizure focus and degree of handedness. A familial history of sinistrality may have an additional effect on the likelihood of atypical dominance

We report the case of a patient with an acute middle cerebral artery occlusion emergently revascularized with a Neuroform self-expanding stent

OBJECTIVE AND IMPORTANCE/OBJECTIVE:Locked-in syndrome is a state of preserved consciousness in the setting of quadriplegia, anarthria, and usually also includes lateral gaze palsy. It is most commonly associated with upper brainstem infarction variably sparing the third cranial nerve nucleus. There are likely many etiologies that contribute to this clinical syndrome. These are incompletely understood, and the syndrome remains a rare but devastating complication that can occur after neurosurgical and neurovascular interventions. Advanced magnetic resonance imaging techniques such as perfusion and diffusion tensor imaging may help to elucidate the mechanism behind locked-in syndrome. To the authors' knowledge, there are no reports in the literature of perfusion and diffusion tensor findings in patients with this syndrome. A postprocedural case of locked-in syndrome is described with abnormalities on perfusion and diffusion tensor imaging in the absence of any changes in conventional magnetic resonance imaging. CLINICAL PRESENTATION/METHODS:A 57-year-old man who presented with acute onset headache, ataxia, and other nonspecific symptoms was found on imaging to have a giant fusiform basilar artery aneurysm. INTERVENTION/METHODS:A saphenous vein graft bypass between the proximal right external carotid artery and P2 segment of the right posterior cerebral artery followed immediately by endovascular embolization of the aneurysm sac and distal left vertebral artery was performed. CONCLUSION/CONCLUSIONS:Postprocedural angiography demonstrated patency of the bypass graft, and diffusion weighted imaging showed no evidence for acute brainstem infarction. Nevertheless, despite technically successful procedures and the absence of abnormalities on conventional magnetic resonance imaging, the patient developed quadriplegia and anarthria and remained in a locked-in state until he expired. Abnormalities were, however, seen on both perfusion and diffusion tensor imaging, where hypoperfusion, increased mean diffusivity, and decreased fractional anisotropy were observed in the ventral brainstem. The findings suggested a disruption of pontine white matter tracts. Advanced imaging techniques may allow us to image important microstructural changes that were previously not discernable and assist in the evaluation of patients with complex neurological sequelae such as locked-in syndrome.

OBJECT: The goal of this study was to quantify the reduction in velocity, vorticity, and shear stresses resulting from the sequential placement of stents across the neck of sidewall cerebral aneurysms. METHODS: A digital particle image velocimetry (DPIV) system was used to measure the pulsatile velocity field within a flexible silicone sidewall intracranial aneurysm model and at the aneurysm neck-parent artery interface in this model. The DPIV system is capable of providing an instantaneous, quantitative two-dimensional measurement of the velocity vector field of 'blood' flow inside the aneurysm pouch and the parent vessel, and its changes at varying stages of the cardiac cycle. The corresponding vorticity and shear stress fields are then computed from the velocity field data. Three Neuroform stents (Boston Scientific/Target), each with a strut thickness between 60 and 65 microm, were subsequently placed across the neck of the aneurysm model and measurements were obtained after each stent had been placed. The authors measured a consistent decrease in the values of the maximal averaged velocity, vorticity, and shear stress after placing one, two, and three stents. Measurements of the circulation inside the sac demonstrated a systematic reduction in the strength of the vortex due to the stent placement. The decrease in the magnitude of the aforementioned quantities after the first stent was placed was remarkable. Placement of two or three stents led to a less significant reduction than placement of the first stent. CONCLUSIONS: The use of multiple flexible intravascular stents effectively reduces the strength of the vortex forming in an aneurysm sac and results in a decrease in the magnitude of stresses acting on the aneurysm wall

A major challenge in stem cell biology is to study the underlying mechanisms of tissue specific homing and differentiation. Recent results suggest that bone marrow derived stem cells can give rise to multiple cell types. Because chemokines and chemokine receptors are associated with development, differentiation and homing of immune cells, we undertook efforts to study the chemokine receptor expression profile of human adult stem cells to identify their potential role in tissue specific homing prior to transdifferentiation. Using human bone marrow-derived stem cell lines, we could demonstrate functional chemokine receptor expression of various chemokine receptors. The expression of CXCR5 and CCR7, associated with secondary lymphoid organ homing as well as CXCR4 and CCR10, involved in organ specific homing and CXCR3, CCR5 and CCR1, which are involved in inflammation events, suggested a role of chemokine receptors in tissue specific homing of stem cells. To proof the specific homing of stem cells in vivo, we used murine stem cell lines, stably introduced green fluorescent protein under control of CMV promotor into the cells and injected them intravenously into mice. We demonstrate the homing of these stem cells to lymphnode and thymus as well as mucosal tissue, while stem cells home exclusively to a site of lesion during wound healing and tissue regeneration. Our data suggest that chemokine biology may play a pivotal role in the homing of stem cells to specific tissues and niches prior to (trans)differentiation, while the homing changes during tissue damage and other adequate lesions

Summary: The pathogenesis of dural arteriovenous fistulas (DAVFs) is currently unknown, with multiple DAVFs being rare. For patients with limited venous access secondary to sinus thrombosis, or for patients where parent sinus occlusion would not be tolerated, transvenous embolization may not be possible and other treatment methods must be considered. A 69-year-old female patient with a two-year history of progressive headaches, memory loss, and unsteady gait underwent cerebral angiography that revealed three separate DAVFs with congested cortical venous drainage overlying both frontal lobes. Using an application of a transarterial wedged-catheter, flow-arrest technique, N-butyl cyanoacrylate was deposited across all three pathologic arteriovenous connections providing a definitive cure. Transarterial NBCA embolization may provide curative treatment of DAVFs, and is of particular utility in situations where access to the draining venous structures is limited

OBJECT: The aim of this study was to describe the application of a novel transarterial approach to curative embolization of complex intracranial dural arteriovenous fistulas (DAVFs). This technique is particularly useful in patients harboring high-grade DAVFs with direct cortical venous drainage or for whom transvenous coil embolization is not possible because of limited sinus venous access to the fistula site due to thrombosis or stenotic changes. METHODS: Twenty-three DAVFs in 21 patients were treated using a transarterial N-butyl cyanoacrylate (NBCA) embolization technique with the aid of a wedged catheter. In all patients, definitive treatment involved two critical steps: 1) a microcatheter was wedged within a feeding artery, establishing flow-arrest conditions within the catheterized vessel distal to the microcatheter tip; and 2) NBCA was injected under these resultant flow-arrest conditions across the pathological arteriovenous connection and into the immediate draining venous apparatus, definitively occluding the fistula. Patient data were collected in a retrospective manner by reviewing office and inpatient charts and embolization reports, and by directly analyzing all procedural and diagnostic angiograms. Eight patients presented with the principal complaint of tinnitus/bruit, five with intracranial hemorrhage, four with cavrnous sinus syndrome, and one each with seizures, ataxia, visual field loss, and hiccups. The parent (recipient) venous structure of the DAVFs in this study included 11 leptomeningeal veins, eight transverse/sigmoid sinuses, three cavernous sinuses, and one sphenoparietal sinus. The NBCA permeated the arteriovenous shunt, perifistulous network, and proximal draining vein in all DAVFs. Occlusion was confirmed on postembolization angiography studies. No complication occurred in any patient in this series. There has been no recurrence during a mean follow up of 18.7 months (range 2-46 months). CONCLUSIONS: Transarterial NBCA embolization with the aid of a wedged catheter in flow-arrest conditions is a safe and an effective treatment for intracranial DAVFs

The authors present the case of a patient who suffered from progressive cranial nerve dysfunction, radiographically documented brainstem compression, and peduncular hallucinosis after undergoing endosaccular coil placement in a giant basilar apex aneurysm. Symptom resolution was achieved following clip ligation of the basilar artery. The pathogenesis of aneurysm mass effect due to coil placement is discussed and the pertinent literature is reviewed