Outcomes of Mechanical Thrombectomy in Patients With Neurological Disorders: A National Inpatient Sample Database Analysis.

INTRODUCTION: Mechanical thrombectomy (MT) has changed the standard of care for patients presenting with acute ischemic stroke (AIS). The window of treatment has significantly increased the number of patients who would benefit from intervention and operators may be confronted with patients harboring preexistent neurological disorders. Still, the epidemiology of patients with AIS and neurological disorders has not been established. METHODS: This is a retrospective study, which utilizes data from the National Inpatient Sample (NIS) between 2012 and 2016. Patients with the major neurological comorbidities in the study were included: Alzheimer's dementia (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS), and myasthenia gravis (MG). These patients were divided into groups and analyzed based on discharged home status, length of hospital stay (LOS), and inpatient mortality. These outcomes were also compared between patients who underwent MT versus those who did not. RESULTS: In this study, 460,070 patients with AIS were identified and included. MT was performed less often when the patient had a neurological diagnosis compared to those without a neurological disease (p<0.0001). However, patients with AIS who have underlying neurological disorders such as AD, PD, and MS have shown similar outcomes after MT to those who do not have these disorders. CONCLUSION: Patients with preexisting neurological disorders were less likely to undergo MT. Further studies are required to elucidate the implications of having a neurological disorder in the setting of an AIS.

Traumatic cervical spine subarachnoid hemorrhage with hematoma and cord compression presenting as Brown-Séqüard syndrome: illustrative case.

BACKGROUND: Spinal hematomas are a rare entity with broad etiologies, which stem from idiopathic, tumor-related, and vascular malformation etiologies. Less common causes include traumatic blunt nonpenetrating spinal hematomas with very few cases being reported. In the present manuscript presents a case report and review of the literature of a rare traumatic entity of a cervical subarachnoid hematoma in association with Brown-Séquard syndrome in a patient on anticoagulants. Searches were performed on PubMed and Embase for specific terms related. OBSERVATIONS: A well-documented case of an 83-year-old female taking anticoagulants with traumatic cervical subarachnoid hematoma presenting as Brown-Séquard syndrome was reported. Six similar cases were identified, scrutinized, and analyzed in the literature review. LESSONS: Traumatic blunt nonpenetrating cervical spine subarachnoid hematomas are a rare entity that can happen more specifically in anticoagulant users and in patients with arthritic changes and stenosis of the spinal canal. Rapid neurological deterioration and severe disability warrant early aggressive surgical treatment. This report has the intention to record this case in the medical literature for registry purposes.

Silk Vista Baby for the Treatment of Complex Posterior Inferior Cerebellar Artery Aneurysms.

BACKGROUND: Treatment of small-caliber vessel lesions using flow diverters remains challenging because of vasculature's narrow luminal diameter and tortuosity. This in turn makes navigation and delivery of conventional devices with standard microcatheters more difficult. The Silk Vista Baby (SVB, Balt) flow diversion device was designed for ease of use in vessels with a smaller diameter, distal lesions, and 0.017 ″ microcatheter delivery systems. OBJECTIVE: To report the outcomes of the SVB device on the treatment of posterior inferior cerebellar artery (PICA) aneurysms. METHODS: Databases from different centers were retrospectively reviewed for PICA aneurysms treated with SVB. Demographic information, clinical presentation, radiographic characteristics, procedural complications, and immediate postprocedure outcomes were obtained. RESULTS: Fourteen patients harboring 15 true PICA aneurysms were treated between January 2019 and June 2021. Nine were female (n = 9/14; 64.2%), and the mean age was 51 ± 14.9 years. Most patients had previously ruptured aneurysms, treated by another endovascular technique. Six aneurysms were located distally (n = 6/15; 40%). The mean neck size was 3 mm (SD 1.35, range 2.5-5 mm), whereas the mean PICA diameter was 1.6 mm (SD 0.26, range 1.5-1.7 mm). The mean length of follow-up was 6 months (SD 8.28, range 4.5-16 months). Treatment-related adverse events included 1 case of transient hypoesthesia. Two additional events were reported, but adjudicated as unrelated to the procedure. Complete occlusion, measured as Raymond-Roy class I, was achieved in all cases. CONCLUSION: The SVB device was safely and effectively used in the treatment of PICA aneurysms. The smaller delivery system profile reduces the risk of procedure complications and creates new treatment options for distal lesions.

Endoscopic Transforaminal Transchoroidal Approach to the Third Ventricle for Cystic and Solid Tumors.

BACKGROUND: Endoscopic access to the third ventricle is limited by the confinements of the foramen of Monro and can be aided by opening of the choroidal fissure. OBJECTIVE: We describe the endoscopic transforaminal transchoroidal (ETTC) approach to the third ventricle with opening of the choroidal fissure to enlarge the posterior foramen of Monro for treatment of various third ventricular diseases. METHODS: We completed a retrospective review of a prospectively collected database at 3 tertiary academic facilities. The search included patients who underwent endoscopic transcranial procedures between 2005 and 2018. All 13 patients included in this study were treated using the ETTC approach for lesions in the third ventricle using a rigid 6-mm working endoscope. RESULTS: There were 7 women and 6 men with a mean age of 44 years (standard deviation, 16 years). Third ventricular diseases included colloid cyst, craniopharyngioma, anaplastic astrocytoma, subependymal giant cell astrocytoma, metastatic lung adenocarcinoma, and lymphoma. Resection was complete in 7 patients and near complete in 4. Two patients had biopsy of a thalamic tumor and third ventriculostomy. The mean follow-up time was 44 months (standard deviation, 36 months; range, 9-121 months). There were no intraoperative or postoperative complications related to the approach. CONCLUSIONS: ETTC approach is a safe and effective method for enlargement of the foramen of Monro. The approach improves maneuverability of the endoscope and allows a broad range of movement and increased angulation within the foramen of Monro. Attention to anatomy is paramount to avoid injury to the venous structures and fornix.

Multiple Extraaxial Cavernous Hemangiomas: Rare Entity.

BACKGROUND: Cavernous hemangiomas arising in the extraaxial space are rarely encountered, often mimicking other more common pathologies. Furthermore, multiple coexisting lesions and posterior fossa involvement are scarcely reported. Herein, we present the case of a patient with concurrent frontal bone and posterior fossa extraaxial cavernous hemangiomas. We also review the challenges associated with the diagnosis and management of these entities. CASE DESCRIPTION: An otherwise healthy 41-year-old gentleman presented with a 7-month history of a progressive right forehead mass. Imaging demonstrated a right frontal bone mass and an incidentally noted transverse sinus-based mass. The patient opted for surgical resection of both lesions. A right frontal craniotomy was performed to remove the bony lesion, followed by a suboccipital approach for the dural-based mass. There were no significant complications intraoperatively, and gross total resection was achieved for both lesions. Final pathology for each was consistent with cavernous hemangioma. CONCLUSIONS: Extraaxial cavernous hemangiomas are uncommon clinical entities that are challenging to distinguish from other diseases. If intraoperative complications can be avoided, treatment with surgical resection often offers excellent patient outcomes.

Safety and Efficacy of Stent-assisted Coiling in the Treatment of Unruptured Wide-necked Intracranial Aneurysms: A Single-center Experience.

INTRODUCTION: Wide-necked intracranial aneurysms (IAs) are complex lesions that may require different microsurgical or endovascular strategies, and stent-assisted coiling (SAC) has emerged as a feasible alternative to treat this subset of aneurysms. METHODS: The objective was to assess the rate of complications of unruptured wide-necked IAs treated with SAC. We retrospectively identified patients with unruptured wide-necked IAs treated with SAC. Medical charts, procedure reports, and imaging studies were analyzed. RESULTS: One hundred twenty patients harboring 124 unruptured wide-necked IAs were included. Ninety-two aneurysms (74.2%) were located in the anterior circulation. The median aneurysm size was 7 mm (IQR = 5-10). The immediate complete aneurysm occlusion rate was 29% (36/124). The rate of procedural complications was 3.3 % (4/120), which included 2 intraprocedural aneurysm ruptures, 1 immediate postprocedure aneurysm rupture, and 1 vessel occlusion rescued with an open-cell stent. The median follow-up time was 21 months (IQR = 10.3-40.9). Kaplan-Meier analysis estimated a median time of complete aneurysm occlusion of 6.3 months (95%CI = 3.8-7.8). At 30-day follow-up, 80.7% of patients had a Glasgow Outcome Score (GOS) of 5 and at the latest follow-up 83.9%. Imaging follow-up was available for 102 patients. The rate of complete aneurysm occlusion was 73.5% (75/102), severe in-stent stenosis (>50%) was found in 1% (1/102), the recanalization rate was 6.6% (5/75), and the retreatment rate was 7.8% (8/102). CONCLUSION: SAC remains a safe and effective technique to treat wide-necked IAs, providing a low rate of complications and recanalization with excellent long-term aneurysm occlusion rates.

Delayed Pipeline Embolization of a Ruptured True Internal Carotid Artery Aneurysm Presenting with Epistaxis: Case Report and Review of the Literature.

BACKGROUND: Massive epistaxis from rupture of an intracavernous internal carotid artery aneurysm is a potentially fatal event. Although rare, this presentation is seen most often in patients after trauma or iatrogenic injury secondary to transsphenoidal surgery or radiation therapy. CASE DESCRIPTION: We present our unusual case of a patient with no significant risk factors who had recurrent epistaxis owing to a ruptured true cavernous internal carotid artery aneurysm. The patient was treated initially with coil embolization followed by placement of a Pipeline embolization device. The patient had complete resolution of her bleeding events. A follow-up arteriogram performed 14 months later confirmed aneurysm obliteration, with parent artery preservation and no evidence of in-stent stenosis. CONCLUSIONS: Our case highlights the importance of evaluating for intracranial pathological conditions in patients who present with refractory epistaxis. In selected patients, the use of flow-diversion technology as an adjunct or alternative to primary coil embolization for treatment should be considered.

Safety and efficacy of cangrelor in acute stenting for the treatment of cerebrovascular pathology: preliminary experience in a single-center pilot study.

BACKGROUND: Treatment of acute cerebrovascular pathology, such as acute ischemic stroke or intracranial aneurysms, presents a challenge if an extracranial or intracranial stent is required; immediate platelet inhibition is vital. To date, there is no standardized approach for antiplatelet inhibition in an acute setting. OBJECTIVE: To report our preliminary experience and lessons learnt using cangrelor in acute neurointervention. METHODS: A single-arm pilot study was performed to assess the safety and efficacy of cangrelor plus aspirin for platelet inhibition in patients who require acute stenting in the setting of neuroendovascular treatment. RESULTS: Eight patients were enrolled between October 2017 and August 2018. Median age was 71 years (53-86). Seven patients were treated in an acute setting according to the stroke protocol at our institution, while one patient was treated for a symptomatic, unruptured aneurysm with flow diversion and coiling. At admission, the median National Institutes of Health Stroke Scale score for the patients with stroke was 12.5 (range 2-22.3). Cangrelor was infused and all patients achieved adequate platelet inhibition (<200 PRU (P2Y12 reaction units)). Six of seven patients with ischemic stroke had a carotid stent placed and one had an intracranial stent deployed in the middle cerebral artery. None of the patients experienced intraprocedural thromboembolic complications, intraprocedural in-stent thrombosis, hemorrhagic complications, or stroke within 24 hours after the intervention. The majority of patients (6/8) had a good clinical outcome at discharge (modified Rankin Scale score 0-2). CONCLUSIONS: Our findings suggest that cangrelor is a promising alternative in acute stenting for the treatment of cerebrovascular pathology. However, further studies with larger samples are required to accurately elucidate its safety and effectiveness in neuroendovascular procedures.

Endovascular Recanalization of Symptomatic Intracranial Arterial Stenosis Despite Aggressive Medical Management.

BACKGROUND: The optimal management of intracranial arterial stenosis is unclear, particularly in patients who have failed medical management. We report a multicenter real-world experience of endovascular recanalization of intracranial atherosclerotic stenosis refractory to aggressive medical therapy. METHODS: Retrospective multicenter case series of consecutive endovascularly treated patients presenting with symptomatic (transient ischemic attack [TIA] or stroke) intracranial stenosis who had failed medical therapy. Patients were divided into 2 groups: patients with recurrent TIA or stroke despite medical management (group 1) versus patients presenting with a stroke and worsening symptoms (progressive or crescendo stroke) despite medical management (group 2). RESULTS: A total of 101 patients were treated in 8 stroke centers from August 2009 to May 2017. Sixty-nine presented with recurrent TIA or stroke and 32 with stroke and worsening symptoms. Successful recanalization was achieved in 84% of patients. Periprocedural stroke occurred in 3 patients and 2 had a recurrent ischemic stroke at the 90-day follow-up. Symptomatic intraparenchymal hemorrhage secondary to reperfusion injury occurred in 3 patients and 1 had a hemorrhagic stroke after discharge. There were 2 periprocedural perforations that resulted in death. At 90 days, 86% of patients (64/74) did not have a recurrence of stroke and the 90-day cumulative ischemic stroke rate was 6.7% with 90-day mortality of 11.2%. The 90-day favorable outcome (modified Rankin Scale score, ≤2) rate was 77.5%. CONCLUSIONS: Endovascular recanalization of unstable intracranial atherosclerotic stenosis in patients who have failed medical therapy is feasible. Future randomized trials need to determine if recanalization is of any value for this population.

Multicenter Study of Pipeline Flex for Intracranial Aneurysms.

BACKGROUND: The Pipeline Flex (PED Flex; Medtronic, Dublin, Ireland) was designed to facilitate deployment and navigation compared to its previous iteration to reduce the rate of technical events and complications. OBJECTIVE: To assess the neurological morbidity and mortality rates of the PED Flex at 30 d. METHODS: Information from 9 neurovascular centers was retrospectively obtained between July 2014 and March 2016. Data included patient/aneurysm characteristics, periprocedural events, clinical, and angiographic outcomes. Multivariate logistic regression was performed to determine predictors of unfavorable clinical outcome (modified Rankin Scale [mRS] > 2). RESULTS: A total of 205 patients harboring 223 aneurysms were analyzed. The 30-d neurological morbidity and mortality rates were 1.9% (4/205) and 0.5% (1/205), respectively. The rate of intraprocedural events without neurological morbidity was 6.8% (14/205), consisting of intraprocedural ischemic events in 9 patients (4.5%) and hemorrhage in 5 (2.4%). Other technical events included difficulty capturing the delivery wire in 1 case (0.5%) and device migration after deployment in another case (0.5%). Favorable clinical outcome (mRS 0-2) was achieved in 186 patients (94.4%) at discharge and in 140 patients (94.5%) at 30 d. We did not find predictors of clinical outcomes on multivariate analysis. CONCLUSION: The 30-d rates of neurological morbidity and mortality in this multicenter cohort using the PED Flex for the treatment of intracranial aneurysms were low, 1.9% (4/205) and 0.5% (1/205), respectively. In addition, technical events related to device deployment were also low, most likely due to the latest modifications in the delivery system.

Ruptured aneurysm of the artery of Adamkiewicz: is conservative management the standard of treatment in the current era?

Spinal aneurysms are rare lesions, and their natural history is not well known. In particular, aneurysms arising from the artery of Adamkiewicz (AA) are an extremely rare phenomenon, and given the lack of solid evidence its management remains unclear. We present the case of a 54-year-old woman with spinal subarachnoid hemorrhage. A spinal angiogram demonstrated a fusiform aneurysm arising from the AA. Based on the location, the absence of evident collateral circulation to the anterior spinal artery, and the available literature supporting spontaneous thrombosis, we opted for conservative management. Fifteen days after the diagnosis, a spinal angiogram demonstrated complete occlusion of the aneurysm with no visualization of the AA. At 10-month follow-up, the patient was able to walk without assistance. Management should be done on a case-by-case basis with the goal of preserving spinal cord perfusion. Similar to previous articles, our report reinforces conservative management as a valid strategy.

Cerebral Aneurysms Differ in Patients with Hysterectomies.

OBJECTIVE: Female sex is a well-known risk factor for aneurysm formation. Although the role of the ovaries and estrogen in aneurysm development has been supported, other organ-hormone pairs unique between sexes also may be implicated. In this study, we aimed to determine whether intracranial aneurysms microsurgically clipped in patients with previous hysterectomies exhibit any unique aneurysm characteristics from those without hysterectomies. METHODS: Solitary aneurysms microsurgically treated by the senior author (M.T.L.) were included from a database of patients treated between January 2010 and April 2013 at a tertiary academic medical center. Only female patients and patients equal or older in age to the youngest patient in the hysterectomy group were included in the control group. Patient and aneurysm characteristics were compared using the χ2 test for categorical variables and the independent t test analysis for continuous variables. RESULTS: A total 233 patients were included in the study. Forty-three patients (19%) had undergone a previous hysterectomy; none had oophorectomies recorded. No difference in mean age (P = 0.89), hypertension (P = 0.38), alcohol use (P = 0.87), tobacco use (P = 0.22), or aneurysm location (P = 1) existed. However, patients in the hysterectomy group more often presented in a good neurologic condition before surgery (88% vs. 74%, P = 0.04) and had fewer large aneurysms (8% vs. 24%, P = 0.03). Also, fewer presented with a ruptured aneurysm (28%) then the nonhysterectomy group (51%) (P = 0.004). CONCLUSIONS: Female patients with a surgical history of a hysterectomy have a lower rate of large aneurysms, present in better neurologic condition, and are less likely to present with a ruptured aneurysm than females without a hysterectomy.

Current Status of the PulseRider in the Treatment of Bifurcation Aneurysms: A Systematic Review.

BACKGROUND: The PulseRider is an innovative stent-like device designed for the treatment of intracranial bifurcation aneurysms. The aim of this study was to assess the current evidence on safety and effectiveness of the PulseRider. METHODS: A systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The following databases were searched: PubMed, Ovid MEDLINE, and Scopus. The search strategy consisted of "pulserider," "bifurcation aneurysm," and "endovascular" in both AND and OR combinations. Studies included were original research articles in peer-reviewed journals. The manuscripts were thoroughly examined for study design, outcomes, and results. RESULTS: Three studies were identified describing use of the PulseRider device in the treatment of 63 patients with 63 bifurcation aneurysms. We identified 2 multicenter case series and 1 single-arm clinical trial. The majority of aneurysms treated were located at the basilar tip (37, 58.7%). All devices were successfully deployed, and there were 5 intraoperative complications (7.9%), including 2 intraoperative aneurysm ruptures, 1 vessel dissection, and 2 thrombus formations. Immediate complete aneurysm occlusion was achieved in 61.9% (39/63) of cases and at the 6-month imaging follow-up, 66.7% (42/63) achieved complete aneurysm occlusion. One recanalization was reported in 1 of the multicenter case series within the 6-month follow-up. CONCLUSIONS: The PulseRider is safe and probably effective for the treatment of intracranial bifurcation aneurysms, sometimes not amenable for stent-assisted coiling. However, current evidence is limited to a small sample and short follow-up. In addition, the device has not been compared with other treatment modalities.

The fate of medical knowledge and the neurosciences during the time of Genghis Khan and the Mongolian Empire.

In 25 years, the Mongolian army of Genghis Khan conquered more of the known world than the Roman Empire accomplished in 400 years of conquest. The recent revised view is that Genghis Khan and his descendants brought about "pax Mongolica" by securing trade routes across Eurasia. After the initial shock of destruction by an unknown barbaric tribe, almost every country conquered by the Mongols was transformed by a rise in cultural communication, expanded trade, and advances in civilization. Medicine, including techniques related to surgery and neurological surgery, became one of the many areas of life and culture that the Mongolian Empire influenced.

Alarming Internal Carotid Artery Aneurysm Eroding the Sphenoid Sinus.

In rare instances, extradural internal carotid artery aneurysms can present with massive epistaxis, which is often a fatal event. We present the case of a young female with an aneurysm eroding through the sphenoid sinus and whose timely diagnosis resulted in treatment of the aneurysm with coil embolization and satisfactory outcome.

First US experience with Pipeline Flex with Shield Technology using aspirin as antiplatelet monotherapy.

Flow diversion has revolutionised the treatment of intracranial aneurysms, and the Pipeline Embolization Device (PED) remains the only flow diverter (FD) approved in the USA. However, thromboembolic events remain an issue for FDs. Attempting to minimise these incidents, a newer PED has been developed with the use of covalent bonding of phosphorylcholine onto the Pipeline device that has been known as Shield Technology (PED Shield), which in vitro has demonstrated a significant reduction in material thrombogenicity. We report the first US experience of the PED Shield in the treatment of a ruptured fusiform aneurysm located in the right vertebral artery in an attempt to mitigate complications related to the use of dual-antiplatelet therapy and discuss our rationale for using the new FD, using aspirin only as the antiplatelet regimen.

Multiple Calcifying Pseudoneoplasms of the Neuraxis.

Calcifying pseudoneoplasms of the neuraxis (CAPNONs) are extremely rare tumors that are frequently misdiagnosed and overlooked by clinicians. To date, only 40 intracranial lesions have been reported, and in all instances, they were found as a solitary calcified mass. To our knowledge, the current case report is the first to illustrate the development of multiple intraaxial CAPNONs and shed more light on the origin of these lesions. We discuss the case of a 67-year-old woman who presented with a six-year history of recurrent seizures. Magnetic resonance imaging revealed two similar heterogeneous intracranial masses in the ventral midbrain and left frontal white matter with indications of more aggressive behavior in the supratentorial tumor. The lesion was resected, and histopathological analysis showed tissue containing nodules of chondromyxoid material with a coarsely fibrillar matrix and focal alveolar pattern. Palisading cells were noted around the edges as well as dystrophic calcifications and osseous metaplasia, consistent with CAPNON. Interestingly, the patient had a previous history of multiple brain abscesses and a mycotic aneurysm. At her four-month follow-up visit, the patient remained seizure-free and there were no indications of residual tumor or recurrence. In contrast to previous reports, intracranial CAPNONs may manifest as multiple lesions and clinicians should include these tumors in the differential diagnosis of intra-axial calcified masses. The previous history of brain abscesses raises the suspicion of an abnormal proliferative process following an insult to the brain tissue as the underlying origin of these lesions.

High-energy Trauma Precipitating Intramedullary Cavernous Malformation Hemorrhage - A Possible Underreported Mechanism.

Cavernous malformations are uncommon vascular lesions with an estimated prevalence of 0.5% in the general population. Intramedullary cavernous malformations (ICM) represent a rare subset of lesions, which account for approximately 5% of all cavernous malformations. The annual risk of hemorrhage in ICMs has been reported to range from 1.4 to 6.8%. Most patients are diagnosed with neurological dysfunction secondary to ICM hemorrhage and little is known about the inciting events that lead to hemorrhage. A few studies have suggested that minor and major trauma or even intense exertion may increase the risk of hemorrhage. We report the case of a 62-year-old male who developed progressive neurological deterioration following a motor vehicle accident. During work-up, an ICM was found at T4 and was surgically removed. At his 10-month follow-up, the patient had partially recovered, regaining motor strength in his right lower extremity, but had a persistent decrease in temperature and pinprick sensation on the left side starting at the T6 dermatome. We hypothesize that ICMs can rupture after high-energy impacts, such as the motor vehicle accident in our patient, and mechanical factors, such as trauma and stretching maneuvers, can play a role in the pathogenesis of ICM hemorrhage.

Ruptured aneurysm of the artery of Adamkiewicz: is conservative management the standard of treatment in the current era?

Spinal aneurysms are rare lesions, and their natural history is not well known. In particular, aneurysms arising from the artery of Adamkiewicz (AA) are an extremely rare phenomenon, and given the lack of solid evidence its management remains unclear. We present the case of a 54-year-old woman with spinal subarachnoid hemorrhage. A spinal angiogram demonstrated a fusiform aneurysm arising from the AA. Based on the location, the absence of evident collateral circulation to the anterior spinal artery, and the available literature supporting spontaneous thrombosis, we opted for conservative management. Fifteen days after the diagnosis, a spinal angiogram demonstrated complete occlusion of the aneurysm with no visualization of the AA. At 10-month follow-up, the patient was able to walk without assistance. Management should be done on a case-by-case basis with the goal of preserving spinal cord perfusion. Similar to previous articles, our report reinforces conservative management as a valid strategy.

Analysis of Predictors and Probability of Aneurysm Occlusion in the Internal Carotid Artery After Treatment with Pipeline Embolization Device.

BACKGROUND: Although the Pipeline Embolization Device (PED) has proved to be an excellent option for internal carotid artery (ICA) aneurysms, the rate of occlusion remains difficult to predict and factors associated with aneurysm occlusion are not well elucidated. This study aimed to investigate predictors and the rate of occlusion for aneurysms along the ICA. METHODS: A total of 117 saccular ICA aneurysms treated with the PED were studied. Occlusion rates were divided among 4 groups: group A [lesions >10 mm in the proximal ICA (petrous to the superior hypophyseal segments)]; group B (lesions <10 mm in the proximal ICA); group C [lesions >10mm in the distal ICA (posterior communicating segment to the ICA bifurcation)]; and group D (lesions <10 mm in the distal ICA). Predictors of aneurysm occlusion were entered into a multivariate Cox regression analysis. RESULTS: The median time to aneurysm occlusion was 8 months in group A (95% confidence interval [CI], 7.0-9.1), 5.2 months in group B (95% CI, 4.5-6.0), 6.9 months in group C (95% CI, 6.5-7.2), and 10.2 months in group D (95% CI, 6.9-13.6) (P = 0.045). There was a statistically significant difference between the probability of aneurysm occlusion in group B compared with distal ICA aneurysms (P = 0.02). Small proximal ICA aneurysms were more likely to occlude over time compared with other aneurysm groups (hazard ratio, 1.76; 95% CI, 1.07-2.9; P = 0.02). CONCLUSIONS: The rate of occlusion after PED is highest for small proximal ICA aneurysms and the probability of occlusion is lower for distal ICA aneurysms.