Dilated Superior Ophthalmic Vein: Clinical and Radiographic Features of 113 Cases.

PURPOSE: Dilated superior ophthalmic vein (SOV) is an uncommon radiographic finding. The authors review the presentation, etiology, radiography, and visual implications of 113 patients with dilated SOV. METHODS: An observational case series and multicenter retrospective chart review were conducted. There were 113 patients with a dilated SOV. Outcome measures included patient demographics, clinical features, radiographic findings, diagnosis, and treatment, and treatment outcomes were assessed. RESULTS: Cases included 75 women (66%) and 38 men (34%) with a mean age of 49 ± 24 years (range, 0.4-90 years). Diagnoses fell under 6 categories: vascular malformation (n = 92, 81%), venous thrombosis (n = 11, 10%), inflammatory (n = 6, 5%), traumatic hemorrhage (n = 2, 2%), lymphoproliferative (n = 1, 1%), and infectious (n = 1, 1%). Imaging modalities utilized included MRI (n = 98, 87%), digital subtraction angiography (n = 77, 68%), CT (n = 29, 26%), and ultrasonography (n = 4, 4%). Disease status at last follow up included no evidence of disease (n = 57, 50%), alive with persistent disease (n = 53, 47%), and expired from disease (n = 3, 3%). Treatment and management was tailored to the underlying disease process with a mean follow up of 18 months (range, 1 day to 180 months). Visual impairment observed at presentation and last follow up across all cases was 26% and 22%, respectively. CONCLUSION: Dilated SOV is a rare radiographic finding resulting from a wide spectrum of etiologies with clinical implications ranging from benign to sight- and life-threatening. Dilated SOV is most often found with dural-cavernous fistula or carotid-cavernous fistula, orbital or facial arteriovenous malformation, and venous thrombosis. Recognition of this finding and management of the underlying condition is critical.

Mobile Interventional Stroke Teams Lead to Faster Treatment Times for Thrombectomy in Large Vessel Occlusion.

BACKGROUND AND PURPOSE: Endovascular recanalization treatment for acute ischemic stroke is a complex, time-sensitive intervention. Trip-and-treat is an interhospital service delivery model that has not previously been evaluated in the literature and consists of a shared mobile interventional stroke team that travels to primary stroke centers to provide on-site interventional capability. We compared treatment times between the trip-and-treat model and the traditional drip-and-ship model. METHODS: We performed a retrospective analysis on 86 consecutive eligible patients with acute ischemic stroke secondary to large vessel occlusion who received endovascular treatment at 4 hospitals in Manhattan. Patients were divided into 2 cohorts: trip-and-treat (n=39) and drip-and-ship (n=47). The primary outcome was initial door-to-puncture time, defined as the time between arrival at any hospital and arterial puncture. We also recorded and analyzed the times of last known well, IV-tPA (intravenous tissue-type plasminogen activator) administration, transfer, and reperfusion. RESULTS: Mean initial door-to-puncture time was 143 minutes for trip-and-treat and 222 minutes for drip-and-ship (P<0.0001). Although there was a trend in longer puncture-to-recanalization times for trip-and-treat (P=0.0887), initial door-to-recanalization was nonetheless 79 minutes faster for trip-and-treat (P<0.0001). There was a trend in improved admission-to-discharge change in National Institutes of Health Stroke Scale for trip-and-treat compared with drip-and-ship (P=0.0704). CONCLUSIONS: Compared with drip-and-ship, the trip-and-treat model demonstrated shorter treatment times for endovascular therapy in our series. The trip-and-treat model offers a valid alternative to current interhospital stroke transfers in urban environments.

Current trends in the management of acute ischemic stroke.

Stroke is the leading cause of disability and most of the cases are those of ischemic stroke. Management strategies especially for large vessel occlusive stroke have undergone a significant change in the recent years that include widespread use of thrombolytic medications followed by endovascular clot removal. For successful treatment by endovascular thrombectomy, the important factors are patient selection based on clinical criterion including age, time of onset, premorbid clinical condition, co-morbidities, National Institute of Health Stroke Scale, and imaging criterion including computed tomography (CT) head, CT angiogram and CT perfusion. Patients presenting within 4.5 hours of onset are considered for intravenous (IV) recombinant tissue plasminogen activator treatment. Mechanical clot retrieval devices have evolved over the past decade. The Mechanical Embolus Removal in Cerebral Ischemia device was approved first followed by the penumbra revascularization system. They have proven in various studies to improve recanalization with acceptable rates of symptomatic intra-cerebral hemorrhage. Introduction of stent retrievers has led to a new era in the interventional management of acute ischemic stroke (AIS). Recent trials namely MRCLEAN, ESCAPE, SWIFT PRIMEs, and EXTEND-IA have used the stent retriever predominantly and have shown unequivocal benefit in the outcome at 90 days for AIS patients with large vessel occlusion. More recently, a new catheter namely 5 MAX ACE was introduced along with improvement in the suction device. This has led to a direct aspiration first pass technique resulting in faster recanalization. Advancements in the endovascular management of AIS with large vessel occlusion have resulted in a paradigm shift in the way this disease is managed. Improvements in patient selection using clinical and imaging criterion along with technical and technological advancements in mechanical thrombectomy have made possible a significantly improved outcome in stroke patients.

Safety and efficacy using a detachable tip microcatheter in the embolization of pediatric arteriovenous malformations.

PURPOSE: The treatment of deep-seeded pediatric brain arteriovenous malformations (AVMs) remains a challenging task. We describe our experience using a new detachable tip microcatheter in the embolization of brain arteriovenous malformations, pial arteriovenous fistulas, and vein of Galen malformations. We describe the safety and efficacy using a new detachable tip microcatheter in the treatment of pediatric deep brain arteriovenous malformations, pial malformations, and vein of Galen malformations. METHODS: During a period of 9 months from March 2013 through January 2014, 11 pediatric patients in 14 procedures with 27 total injections were selected for treatment with a detachable tip under Food and Drug Administration (FDA) compassionate use exemption and were admitted to our department for treatment of their brain AVM using a liquid embolic agent and a detachable tip microcatheter. The ages of the patients ranged from 3 months to 18 years old. RESULTS: Of the 27 total injections done, the tip detached in seven cases. For the 16 n-BCA injections, the tip detached six times (37.5 %), and for the 11 Onyx injections, the tip detached one time (9 %). There were no cases of premature microcatheter detachment during normal vessel navigation. CONCLUSIONS: The introduction of these detachable tip microcatheters allows for a safe and relaxed injection that permits a true circumferential occlusion, and may further permit filling a larger amount of angioarchitecture without the risk of distal migration, or vessel damage during the usual rapid removal of non detachable micocatheters.

Silicone models as basic training and research aid in endovascular neurointervention--a single-center experience and review of the literature.

The rapid development and wider use of neurointerventional procedures have increased the demand for a comprehensive training program for the trainees, in order to safely and efficiently perform these procedures. Artificial vascular models are one of the dynamic ways to train the new generation of neurointerventionists to acquire the basic skills of material handling, tool manipulation through the vasculature, and development of hand-eye coordination. Herein, the authors present their experience regarding a long-established training program and review the available literature on the advantages and disadvantages of vascular silicone model training. Additionally, they present the current research applications of silicone replicas in the neurointerventional arena.

Onyx embolization using dual-lumen balloon catheter: initial experience and technical note.

INTRODUCTION: Onyx as an embolization agent for the management of vascular malformation is well established. We report our initial experience with dimethyl-sulphoxide (DMSO) compatible double lumen balloon catheters used for Onyx embolization. METHODS AND TECHNIQUE: Between December 2011 and March 2013, we treated 22 patients aged between 1.5 to 70years with two types of DMSO compatible dual-lumen balloon catheters (Scepter C and Ascent) to treat dural arteriovenous fistulas, brain arteriovenous malformation (AVM) with dural feeders, mandibular, facial, lingual, vertebral and paravertebral AVMs. The catheter has good navigability, compliant balloon on inflation formed a "plug" that has more resistance than Onyx plug enhancing better penetration. During injection, the balloon remained stable without spontaneous deflation or rupture and withstood the pressure build-up well. The retrieval of the catheter in most cases took less than a minute (19/28) while in five, it was less than five minutes and in the remaining four, it was longer that includes a trapped catheter on prolonged attempted retrieval resulted in an epidural hematoma, requiring emergent surgical evacuation. The fluoroscopy time is reduced, as we do not form a proximal onyx plug, the injection time is shorter along with easy and instantaneous removal of the catheter after balloon deflation in most cases. CONCLUSION: Dual-lumen balloon catheter Onyx embolization is a safe and effective technique. Currently, an important tool to circumvent some of the shortcomings associated with Onyx embolization. The catheter has good navigability, the balloon has stability, tolerance, enhances penetrability. It is easy to retrieve the microcatheter. With the experience gained, and with more compliant balloon catheters available, this technique can be applied to cerebral vessels in near future.

The persistent primitive marginal sinus-observations in children with Vein of Galen malformation.

INTRODUCTION: Knowledge of venous anatomy and drainage in children with neurovascular diseases is crucial. The primitive marginal sinuses (PMS) are embryonic sinuses forming the later superior sagittal sinus. Their angiographic persistence has not been reported before. The purpose of this study is to demonstrate the angiographic characteristics in children with Vein of Galen malformation and to discuss their embryology and clinical significance. METHODS: We retrospectively reviewed digital subtraction angiography and magnetic resonance venography of 102 Vein of Galen malformations (VGM) from the database of two high-load centres for paediatric neurovascular diseases. RESULTS: We found 10 persistent PMS in 102 children indicating a frequency of 9.8 %. Illustrative cases are shown to demonstrate the vast spectrum of venous variability. The PMS becomes visualised in situations of high-flow arteriovenous shunt in children and can even disappear or remodel after successful shunt reduction or closure. CONCLUSION: Knowledge and recognition of the PMS are important for neurointerventionalists in endovascular treatment planning using the transvenous route and can help neurosurgeons in avoiding severe surgical complications.

Rescue Stenting for Refractory Large Vessel Occlusions in the Thrombectomy Era: Intracranial Use of Coronary Stents in Low-mid Economic Settings.

BACKGROUND:  Failed mechanical thrombectomy due to a refractory emergent large vessel occlusion (RELVO) in patients presenting with an acute stroke poses a major challenge to the outcomes. OBJECTIVE:  We demonstrate the use of coronary stents in the intracranial circulation as rescue stenting for an already expensive mechanical thrombectomy procedure in a mid-low socioeconomic setting. METHODS:  A retrospective, multicenter study was conducted between December 2015 and January 2021. The studied cohort were patients who required the use of a rescue stenting using a coronary stent for emergent large vessel occlusion to avoid failed recanalization. Failed recanalization was defined as failed vessel recanalization after at least two passes. Patient demographic data, procedure specifics, type of stent used, and procedural outcomes were collected. RESULTS:  A total of 26 patients with acute ischemic stroke were included from eight different centers across India. Out of 26 patients, 19 (73.0%) were male and seven were female (26.9%). The mean age was 53.6 years, the youngest patient was 23 years old and the eldest was 68 years old. Seven patients (26.9%) had posterior circulation stroke due to occlusion of the vertebral or basilar artery and 19 patients (73.0%) had anterior circulation stroke median NIHSS at presentation was 16 (range 10 to 28) in anterior circulation stroke and 24 (range 16 to 30) in posterior circulation stroke. Intravenous thrombolysis with tissue plasminogen activator (IV tPA) was given in three patients (11.5%). The hospital course of two patients was complicated by symptomatic intracranial hemorrhage (sICH), which was fatal. Favorable revascularization outcome and favorable functional outcome was achieved in 22 patients (84.6%), three patients passed away (11.5%), and one patient was lost to follow up. CONCLUSIONS:  Overall, our study finds that rescue stenting using coronary stents can potentially improve outcomes in refractory large vessel occlusions while minimizing costs in low-mid economic settings.

Hydrocephalus in Vein of Galen Malformations.

Vein of Galen malformation (VOGM) is a fistulous arteriovenous malformation presenting in the early childhood. Hydrocephalus with VOGM develops in one half of patients during the course of the disease. The concept of hydrodynamic disorders is the key to understand the development of hydrocephalus. VOGM results in venous hypertension that secondarily disturbs cerebrospinal fluid (CSF) absorption leading to hydrocephalus and occurs frequently in infants and young children. The medullary veins are thought to be the main pathway for absorption of CSF by the cerebrofugal gradient act as the driving force. In neonates, the cavernous sinus is poorly developed and brain does not use it for venous drainage along with poor jugular bulb maturation results in poor venous drainage reserve. The presence of high flow vascular malformation with poor venous drainage reserve leads to hydrodynamic disorder, poor CSF absorption, and hydrocephalus. Apart from this, hydrocephalus secondary to intraventricular hemorrhage and physical obstruction of the enlarged VOGM at the aqueduct has been proposed. The management strategy is to perform timely endovascular treatment to correct the hydrodynamic disorder and avoid ventricular shunting. Trans-arterial embolization is the effective way, as it decreases flow in the malformation, secondarily the venous hypertension, and thereby improving the clinical symptoms related to hydrodynamic disorder. Ventricular diversion procedure is indicated in symptomatic hydrocephalus after exhausting our effort to reduce hydrodynamic pressure by endovascular embolization.

Vein of Galen Aneurysmal Malformation: Advances in Management and Endovascular treatment.

BACKGROUND: Vein of Galen aneurysmal malformation (VGAM) is a rare congenital vascular malformation representing <1% of all arteriovenous malformations. The knowledge and strategies in the management are constantly evolving. OBJECTIVE: To review our series of postneonatal VGAM patients treated over 11-yr period. METHODS: Retrospective analysis of 113 VGAM treated between January 2004 and April 2015. After exclusions, 45 patients were included: 33 choroidal and 12 mural types. RESULTS: Presenting symptom in the order of frequency: enlarged head circumference, antenatal diagnosis, mild CHF, and PHT at birth. Older patients were diagnosed following trauma, headache, cognitive decline, and incidentally during workup for other diseases. Hydrocephalus due to hydrodynamic disorder was present in 70% of choroidal and 58% of mural types. Only a quarter needed cerebrospinal fluid diversion procedure. Radiological cure was achieved in 82%; the outcome graded on a 5-point scale: 0 (death) to 4 (normal). A total of 66.6% are neurologically and developmentally intact with outcome score 4, 20% had outcome score of 3, and 8.9% had outcome score of 2. There was 4.4% mortality. Dural feeders to VGAM were found either in the initial or during the treatment in 22.2% in the current series. Angiogenesis from pial vessels developed after partial embolization in 17.7% that resolved completely following complete obliteration of VGAM. CONCLUSION: Technical and technological advancements in endovascular embolization along with better understanding of clinical, anatomic, and pathophysiological aspects have resulted in significantly improved outcome and prognosis in VGAM. Most patients with proper treatment can now survive and most develop normally following appropriately timed treatment.

Pediatric neurointervention: collimation on radiation exposure-associated lifetime excess tumor risk.

BACKGROUND: Intracranial vascular malformations in children are being addressed through a variety of treatment modalities including open surgery, external beam radiation, and image-guided neuroendovascular procedures. These patients often receive multiple treatments and incur serial exposures to ionizing radiation which has been linked to tumor development in population-based data. OBJECTIVE: This study quantifies the effect of collimation on exposures from single procedures and over patient lifetimes to estimate excess risk of lifetime tumor development. METHODS: 215 patients aged 0-21 years from a single center took part in the study. Radiation exposure from neuroendovascular procedures was tabulated and converted to brain doses using modeled data and extrapolated to risk ratios using results of population-based estimates found in the literature. RESULTS: Lifetime and per procedure risk was highest in patients with brain arteriovenous malformations, brain arteriovenous fistulas, and vein of Galen malformations, a reflection of our institutional referral patterns. Across all pathologies the per procedure excess relative risk decreased from 13.4 to 2.3 when full collimation was employed. Lifetime excess relative risk decreased from 49.0 to 7.7 for full collimation. CONCLUSIONS: This is the first study to quantify the effect of collimation on lifetime and per procedure risk of tumor development in a pediatric population. In addition to collimation, technical and operator-based aspects of the neurointerventional suite are discussed to further reduce patient exposure without sacrificing image quality.

Factors associated with successful revascularization using the aspiration component of ADAPT in the treatment of acute ischemic stroke.

INTRODUCTION: ADAPT (a direct aspiration first pass technique) has been shown to be fast, cost-effective, and associated with excellent angiographic and clinical outcomes in the treatment of acute ischemic stroke (AIS). OBJECTIVE: To identify any and all preoperative factors that are associated with successful revascularization using aspiration alone. METHODS: A retrospective review of 76 patients with AIS treated with thrombectomy was carried out. Cohort 1 included cases in which aspiration alone was successful (Thrombolysis in Cerebral Infarction 2b or 3). Cohort 2 included cases in which aspiration was unsuccessful or could not be performed despite an attempt. RESULTS: There was no difference between cohorts in gender, race, medications, National Institute of Health Stroke Scale score, IV tissue plasminogen activator, site or side of the occlusion, dense vessel sign, aortic arch type, severe stenosis, clot length, operator years of experience, and guide/aspiration catheters used. Patients in cohort 1 were on average younger (66.5 vs 74.1 years, p=0.025). There was a trend for more patients in cohort 2 to have atrial fibrillation/arrhythmias (62.5% vs 45.5%, p=0.168) and have a cardiogenic stroke etiology (78.1% vs 56.8%, p=0.086). There was also a trend for more reverse curves (2.3 vs 1.7, p=0.107), larger vessel diameter (3.26 mm vs 2.88 mm, p=0.184), larger vessel-to-catheter ratio (2.09 vs 1.87, p=0.192), and worse clot burden score (5.38 vs 6.68, p=0.104) in cohort 2. CONCLUSIONS: Aspiration success was associated with younger age. Our findings suggest that ADAPT can be used for the vast majority of patients but it may be beneficial to use a different method first in the elderly.

Endovascular Management of Sigmoid Sinus Diverticulum.

Sigmoid sinus diverticulum (SSD) is a rare vascular disorder due to dehiscence of the sigmoid plate. It may be associated with prediverticular venous sinus stenosis (SS) and usually presents as pulsatile tinnitus. The mechanism of development of the SSD and tinnitus from a sinus diverticulum and associated SS is unclear. Previous case reports have suggested that remodeling of the venous system targeting the stenosis, elimination of the diverticulum, or both, have resulted in symptom relief. We present a case of SSD with SS, treated by stenting of the stenosis along with coil embolization of the diverticulum, resulting in complete relief of symptoms. We have also reviewed the literature and discussed the evolution of management from open surgical treatment to endovascular treatment.

Endoscopic transmucosal direct puncture sclerotherapy for management of airway vascular malformations.

OBJECTIVES/HYPOTHESIS: To describe a multidisciplinary approach to the treatment of airway vascular malformations (venous or lymphatic) with direct suspension rigid laryngoscopy and direct puncture transmucosal bleomycin sclerotherapy injected under road-mapping fluoroscopic monitoring, supplemented by Dyna-computed tomography utilization. STUDY DESIGN: Case series. METHODS: We performed a retrospective medical record and imaging review of four patients with venous malformations or lymphatic malformations located in the airway. Patients were treated with a combination of direct suspension laryngoscopy or rigid nasopharyngoscopy and image-guided direct puncture bleomycin sclerotherapy. RESULTS: Two patients presented to our institution with extensive lymphatic malformation of the neck, parapharyngeal, and retropharyngeal spaces, and two presented with venous malformation of the nasopharynx and oropharynx. All patients were treated with multiple sclerotherapy and debulking procedures before undergoing combined direct transmucosal puncture bleomycin sclerotherapy guided by direct laryngoscopy or nasopharyngoscopy. All patients had complete resolution of disease while maintaining a safe airway. CONCLUSIONS: A multidisciplinary approach to airway vascular malformations with a combination of endoscopy and direct puncture bleomycin sclerotherapy was demonstrated to be a safe and effective treatment in our patient cohort. Direct laryngoscopy and nasopharyngoscopy provide easy access to the nasopharynx, oropharynx, retro- and/or parapharyngeal spaces and larynx. Unlike traditional agents, bleomycin induces minimal edema and therefore is an ideal substance to treat airway lesions.

The impact of evidence: evolving therapy for acute ischemic stroke in a large healthcare system.

BACKGROUND: With a recent surge of clinical trials, the treatment of ischemic stroke has undergone dramatic changes. OBJECTIVE: To evaluate the impact of evidence and a revamped stroke protocol on a large healthcare system. METHODS: A retrospective review of 69 patients with ischemic stroke treated with intra-arterial therapy was carried out. Cohort 1 included patients treated before implementation of a new stroke protocol, and cohort 2 after implementation. Angiographic outcome was graded using the Thrombolysis in Cerebral Infarction (TICI) score. Clinical outcomes were assessed using the National Institute of Health Stroke Scale (NIHSS) and modified Rankin Scale (mRS). RESULTS: Primary outcomes comparing cohorts demonstrated decreased arrival-to-puncture time (cohort 2: 104 vs cohort 1: 181 min, p<0.001), similar TICI 2b/3 rates (86.5% vs 81.3%, p=0.5530), and similar percentage of patients with discharge mRS 0-2 (18.9% vs 21.9%, p=0.7740). Notable secondary outcomes for cohort 2 included decreased puncture-to-first pass time (34 vs 53 min, p <0.001), increased TICI 3 rates (37.8% vs 18.8%, p=0.0290), a trend toward greater improvements in NIHSS on postoperative day 1 (6.8 vs 2.6, p=0.0980) and discharge (9.5 vs 6.7, p=0.1130), and a trend toward increased percentage of patients discharged with mRS 0-3 (48.6% vs 34.4%, p=0.3280 NS). There were similar rates of symptomatic intracerebral hemorrhage (10.8% vs 9.4%, p=0.9570) and death (10.8% vs 15.6%, p=0.5530). CONCLUSIONS: An interdisciplinary and rapid response to the emergence of strong clinical evidence can result in dramatic changes in a large healthcare system.

N-butyl cyanoacrylate embolization using a detachable tip microcatheter: initial experience.

INTRODUCTION: Endovascular embolization of intracranial vascular malformations with N-butyl cyanoacrylate (nBCA) using a detachable tip microcatheter allows prolonged injection and decreases the risk of catheter retention. METHODS: Between March and December 2013, the Apollo 1.5 cm detachable tip microcatheter was used in five patients after being approved by both the Food and Drug Administration and the institutional review board as a compassionate use device. Nine pedicles were embolized and the follow-up ranged from 1 to 3 months. RESULTS: Five of the nine catheter tips detached. The length of reflux was not directly associated with the detachment of the distal tip. There were no cases of premature microcatheter detachment during navigation, manipulation with multiple microguidewire reintroduction and guidance. There was no leak of embolic agent at the detachment zone. Follow-up showed the detached tip to be stable without migration. CONCLUSIONS: A detachable tip microcatheter offers an advance in the safety and effectiveness of nBCA embolization. Catheter retrieval becomes more controlled and less traumatic. Our initial experience is encouraging, and more experience is needed to categorically ascertain its safety and efficacy.

High-flow carotid cavernous fistula and the use of a microvascular plug system: initial experience.

PURPOSE: We report our initial experience using a detachable microvascular plug system to occlude the internal carotid artery during endovascular treatment of high-flow carotid cavernous fistula. CASE AND TECHNIQUE: An 87-year-old patient was admitted for acute-onset double vision with associated right-eye ptosis. Exam revealed a pupil-sparing, partial right third cranial nerve palsy. MRI showed a carotid cavernous fistula with high-flow drainage. Digital subtraction angiography showed a high-flow, right-sided, direct carotid cavernous fistula with flow from the proximal right internal carotid artery. The ophthalmic artery, posterior communicating artery and anterior communicating arteries supplied retrograde flow to the fistula through the internal carotid artery. Obliteration of the fistula was achieved through coil embolization in combination with proximal and distal microvascular plugs (Reverse Medical, Irvine, Calif., USA). CONCLUSION: The microvascular plug is a new addition to current endovascular embolization devices for the treatment of high-flow, direct carotid cavernous fistulas. This technique offers easy navigability through tortuous arteries, precise localization and immediate occlusion, which may allow shorter procedure and fluoroscopy times and increased cost-effectiveness. Larger case series are needed to support our observation.

Association of a Distal Intradural-Extracranial Posterior Inferior Cerebellar Artery Aneurysm With Chiari Type I Malformation: Case Report.

BACKGROUND AND IMPORTANCE: Distal extracranial posterior inferior cerebellar artery (PICA) aneurysms are very rare lesions and have not been previously reported in association with a Chiari type I malformation (CMI). CLINICAL PRESENTATION: A 56-year-old woman with a distal, low-lying, intradural-extracranial PICA aneurysm presented with a subarachnoid hemorrhage and was treated with coil embolization. The patient presented again 1 month later with symptoms of a CMI and was found to have tonsillar herniation and a large syrinx that appeared to be exacerbated by the coil mass. The patient was re-treated with a suboccipital craniectomy, C1-2 laminectomy, aneurysm trapping and excision, end-to-end PICA anastomosis, and expansile duraplasty. CONCLUSION: Although just a single case, important teaching points regarding the angiographic appearance of a CMI and treatment options for distal PICA aneurysms that are situated below the foramen magnum can be learned. A low-lying caudal PICA loop should trigger a workup for a CMI. Caution should be taken when using coil embolization for aneurysms in the high cervical spinal canal. Bypass with aneurysm trapping and excision may be a superior treatment option in these cases because the posterior fossa and high cervical canal can be concomitantly decompressed. To our knowledge, this is the only case reported of a distal intradural-extracranial PICA aneurysm associated with a CMI.

Predictors of success following endovascular retreatment of intracranial aneurysms.

INTRODUCTION: Although approximately one in every 10 patients undergoing coil embolization of intracranial aneurysms requires retreatment, the factors that are associated with outcome following retreatment remain to be fully elucidated. METHODS: This is a single-center, retrospective review of 43 patients with 58 intracranial aneurysms that were retreated from 2004 to 2014. Aneurysms undergoing first time or microsurgical retreatment were excluded. Retreatment types were grouped into those without permanent parent vessel support (stand-alone and balloon-assisted coiling) versus those with permanent parent vessel support (stent-assisted coiling, stand-alone stenting, and flow diversion). The Modified Raymond Roy Classification was used to group aneurysms at all angiographic follow-up points either in the successful outcome group (Class I or II) or the unsuccessful outcome group (Class IIIa or IIIb). RESULTS: Of aneurysms with follow-up, 50% were in the successful group and 50% in the unsuccessful group. In univariate analysis, small aneurysm size (p < 0.001), previous treatment type (p = 0.022), retreatment type (p = 0.001), and initial occlusion class (p = 0.005) were all associated with angiographic outcome. In multivariate analysis, small aneurysm size (p = 0.005, odds ratio (OR) 24.56, confidence interval (CI) 2.68-225.4) and retreatment type with permanent parent vessel support, namely stent-assisted coiling (p = 0.017, OR 31.1, CI 1.89-517.7), were associated with retreatment success. CONCLUSIONS: Small aneurysm size and retreatment with permanent parent vessel support, namely stent-assisted coiling, are predictors of success following endovascular retreatment of intracranial aneurysms. These findings could be useful in the effort to both prevent and predict treatment failure following endovascular retreatment.