StrokeNet: An automated approach for segmentation and rupture risk prediction of intracranial aneurysm.

Intracranial Aneurysms (IA) present a complex challenge for neurosurgeons as the risks associated with surgical intervention, such as Subarachnoid Hemorrhage (SAH) mortality and morbidity, may outweigh the benefits of aneurysmal occlusion in some cases. Hence, there is a critical need for developing techniques that assist physicians in assessing the risk of aneurysm rupture to determine which aneurysms require treatment. However, a reliable IA rupture risk prediction technique is currently unavailable. To address this issue, this study proposes a novel approach for aneurysm segmentation and multidisciplinary rupture prediction using 2D Digital Subtraction Angiography (DSA) images. The proposed method involves training a fully connected convolutional neural network (CNN) to segment aneurysm regions in DSA images, followed by extracting and fusing different features using a multidisciplinary approach, including deep features, geometrical features, Fourier descriptor, and shear pressure on the aneurysm wall. The proposed method also adopts a fast correlation-based filter approach to drop highly correlated features from the set of fused features. Finally, the selected fused features are passed through a Decision Tree classifier to predict the rupture severity of the associated aneurysm into four classes: Mild, Moderate, Severe, and Critical. The proposed method is evaluated on a newly developed DSA image dataset and on public datasets to assess its generalizability. The system's performance is also evaluated on DSA images annotated by expert neurosurgeons for the rupture risk assessment of the segmented aneurysm. The proposed system outperforms existing state-of-the-art segmentation methods, achieving an 85 % accuracy against annotated DSA images for the risk assessment of aneurysmal rupture.

Toward Grading Subarachnoid Hemorrhage Risk Prediction: A Machine Learning-Based Aneurysm Rupture Score.

OBJECTIVE: Existing approaches neither provide an accurate prediction of subarachnoid hemorrhage (SAH) nor offer a quantitative comparison among a group of its risk factors. To evaluate the population, hypertension, age, size, earlier subarachnoid hemorrhage, and location (PHASES) and unruptured intracranial aneurysm treatment score (UIATS) scores and develop an Artificial Intelligence-based 5-year and lifetime aneurysmal rupture criticality prediction (ARCP) score for a set of risk factors. METHODS: We design various location-specific and ensemble learning models to develop lifetime rupture risk, employ the longitudinal data to develop a linear regression-based model to predict an aneurysm's growth score, and use the Apriori algorithm to identify risk factors strongly associated with SAH. We develop ARCP by integrating output of Apriori algorithm and ML models and compare with PHASES and UIATS scores along with the scores of a multidisciplinary team of neurosurgeons. RESULTS: The PHASES and UIATS scores show sensitivities of 22% and 35% and specificities of 76% and 79%, respectively. Location-specific models show precision and recall of 93% and 90% for the middle cerebral artery, 83% and 80% for the anterior communicating artery, and 80% and 80% for the supraclinoid internal carotid artery, respectively. The ensemble method shows both precision and recall of 80%. The validation of the models shows that ARCP performs better than our control group of neurosurgeons. Data-driven knowledge produces comparisons among 61 risk factor combinations, 11 ranked minor, 8 moderate, and 41 severe, and 1 of which is a critical factor. CONCLUSIONS: The PHASES and UIATS are weak predictors, and the ARCP score can identify, and grade, risk factors associated with SAH.

Introducing the Rupture Criticality Index to Compare Risk Factor Combinations Associated With Aneurysmal Rupture.

BACKGROUND: Relative risk is insufficient to guide treatment decision-making for unruptured intracranial aneurysms. Our objective was to introduce a novel risk assessment methodology called the Rupture Criticality Index (RCI), which allows for concurrent evaluation of groups of risk factors (RFs). METHODS: From a retrospective database of saccular aneurysms, we identify 915 patients and delineate 50 potential RFs for aneurysms in 11 unique locations. RF combinations for multivariable analysis were defined by aneurysm size, location, and a third variable from the study design. Data analysis was performed by applying frequency distribution methods to define the RCI of each RF combination. RESULTS: RF combinations at greatest risk were small (4.8-8.2 mm) or medium (8.3-14.5 mm) anterior communicating aneurysms (ACoA) in male individuals (RCI 9.87-10), small ACoA in those ≤37 years or 38-55 years (RCI 8.67-8.99), medium basilar tip aneurysms (BTAs) in male individuals (RCI 10), and large (14.6-22.5 mm) BTA in Caucasians or those aged 38-55 years (RCI 9.25, 9.35, respectively). CONCLUSIONS: We introduce the concept of RCI and compare how RF combinations are associated with aneurysmal rupture. This novel approach to aneurysmal rupture identifies high-risk clinical presentations and can be used to guide clinical decision-making in patients with non-traditional risks.

Clinical Context-Aware Biomedical Text Summarization Using Deep Neural Network: Model Development and Validation.

BACKGROUND: Automatic text summarization (ATS) enables users to retrieve meaningful evidence from big data of biomedical repositories to make complex clinical decisions. Deep neural and recurrent networks outperform traditional machine-learning techniques in areas of natural language processing and computer vision; however, they are yet to be explored in the ATS domain, particularly for medical text summarization. OBJECTIVE: Traditional approaches in ATS for biomedical text suffer from fundamental issues such as an inability to capture clinical context, quality of evidence, and purpose-driven selection of passages for the summary. We aimed to circumvent these limitations through achieving precise, succinct, and coherent information extraction from credible published biomedical resources, and to construct a simplified summary containing the most informative content that can offer a review particular to clinical needs. METHODS: In our proposed approach, we introduce a novel framework, termed Biomed-Summarizer, that provides quality-aware Patient/Problem, Intervention, Comparison, and Outcome (PICO)-based intelligent and context-enabled summarization of biomedical text. Biomed-Summarizer integrates the prognosis quality recognition model with a clinical context-aware model to locate text sequences in the body of a biomedical article for use in the final summary. First, we developed a deep neural network binary classifier for quality recognition to acquire scientifically sound studies and filter out others. Second, we developed a bidirectional long-short term memory recurrent neural network as a clinical context-aware classifier, which was trained on semantically enriched features generated using a word-embedding tokenizer for identification of meaningful sentences representing PICO text sequences. Third, we calculated the similarity between query and PICO text sequences using Jaccard similarity with semantic enrichments, where the semantic enrichments are obtained using medical ontologies. Last, we generated a representative summary from the high-scoring PICO sequences aggregated by study type, publication credibility, and freshness score. RESULTS: Evaluation of the prognosis quality recognition model using a large dataset of biomedical literature related to intracranial aneurysm showed an accuracy of 95.41% (2562/2686) in terms of recognizing quality articles. The clinical context-aware multiclass classifier outperformed the traditional machine-learning algorithms, including support vector machine, gradient boosted tree, linear regression, K-nearest neighbor, and naïve Bayes, by achieving 93% (16127/17341) accuracy for classifying five categories: aim, population, intervention, results, and outcome. The semantic similarity algorithm achieved a significant Pearson correlation coefficient of 0.61 (0-1 scale) on a well-known BIOSSES dataset (with 100 pair sentences) after semantic enrichment, representing an improvement of 8.9% over baseline Jaccard similarity. Finally, we found a highly positive correlation among the evaluations performed by three domain experts concerning different metrics, suggesting that the automated summarization is satisfactory. CONCLUSIONS: By employing the proposed method Biomed-Summarizer, high accuracy in ATS was achieved, enabling seamless curation of research evidence from the biomedical literature to use for clinical decision-making.

Racial disparities in the diagnosis and management of trigeminal neuralgia.

OBJECTIVE A number of studies have documented inequalities in care and outcomes for a variety of clinical conditions. The authors sought to identify racial and socioeconomic disparities in the diagnosis and treatment of trigeminal neuralgia (TN), as well as the potential underlying reasons for those disparities, which could serve as areas of focus for future quality improvement initiatives. METHODS The medical records of patients with an ICD-9 code of 350.1, signifying a diagnosis of TN, at the Henry Ford Medical Group (HFMG) in the period from 2006 to 2012 were searched, and clinical and socioeconomic data were retrospectively reviewed. Analyses were conducted to assess potential racial differences in subspecialty referral patterns and the specific type of treatment modality undertaken for patients with TN. RESULTS The authors identified 652 patients eligible for analysis. Compared with white patients, black patients were less likely to undergo percutaneous ablative procedures, stereotactic radiosurgery, or microvascular decompression (p < 0.001). However, there was no difference in the likelihood of blacks and whites undergoing a procedure once they had seen a neurosurgeon (67% vs 70%, respectively; p = 0.712). Blacks and whites were equally likely to be seen by a neurologist or neurosurgeon if they were initially seen in either the emergency room (38% vs 37%, p = 0.879) or internal medicine (48% vs 50%, p = 0.806). Among patients diagnosed (268 patients) after the 2008 publication of the European Federation of Neurological Societies and the American Academy of Neurology guidelines for medical therapy for TN, fewer than 50% were on medications sanctioned by the guidelines, and there were no statistically significant racial disparities between white and black patients (p = 0.060). CONCLUSIONS According to data from a large database from one of the nation's largest comprehensive health care systems, there were significant racial disparities in the likelihood of a patient undergoing a procedure for TN. This appeared to stem from outside HFMG from a difference in referral patterns to the neurologists and neurosurgeons.

Arteriovenous malformations of the corpus callosum: Pooled analysis and systematic review of literature.

BACKGROUND: Arteriovenous malformations (AVMs) of the corpus callosum (CC) are rare entities. We performed a systematic review of the available literature to better define the natural history, patient characteristics, and treatment options for these lesions. METHODS: A MEDLINE, Google Scholar, and The Cochrane Library search were performed for studies published through June 2015. Data from all eligible studies were used to examine epidemiology, natural history, clinical features, treatment strategies, and outcomes of patients with CC-AVMs. A systematic review and pooled analysis of the literature were performed. RESULTS: Our search yielded 37 reports and 230 patients. Mean age at presentation was 26.8 years (±13.12 years). AVMs were most commonly located in the splenium (43%), followed by the body (31%), and then the genu (23%) of the CC. A Spetzler-Martin grade of III was the most common (37%). One hundred eighty-seven (81.3%) patients presented with hemorrhage, 91 (40%) underwent microsurgical excision, and 87 (38%) underwent endovascular embolization. Radiosurgery was performed on 57 (25%) patients. Complete obliteration of the AVM was achieved in 102 (48.1%) patients and approximately twice as often when microsurgery was performed alone or in combination with other treatment modalities (94% vs. 49%; P < 0.001). Mean modified Rankin Scale (mRS) at presentation was 1.54 and mean mRS at last follow-up was 1.31. This difference was not statistically significant (P = 0.35). CONCLUSION: We present an analysis of the pooled data in the form of a systematic review focusing on management of CC-AVMs. This review aims to provide a valuable tool to aid in decision making when dealing with this particular subtype of AVM.

Surgical Management of Dural Arteriovenous Fistula After Craniotomy: Case Report and Review of Literature.

BACKGROUND: Development of dural arteriovenous fistula (dAVF) with cortical venous drainage at the site of previous craniotomy is a rare manifestation of nontraumatic subarachnoid hemorrhage (SAH). The authors present a case of postcraniotomy dAVF formation and discuss plausible underlying mechanisms of fistula formation and treatment options as well as review the literature. CASE DESCRIPTION: A 62-year-old man, who had undergone craniotomy 2 decades previously, presented with SAH. Workup revealed a low-flow dAVF with leptomeningeal venous drainage at the posterior margin of the craniotomy. Surgical resection of fistula was undertaken that resulted in cure. CONCLUSIONS: Spontaneous SAH in patients with a previous history of an intracranial procedure (e.g., craniotomy, ventriculostomy) should prompt detailed imaging evaluation. In the absence of vascular disease, meticulous review of the angiogram must be undertaken to rule out dAVF at the procedure site and it should be treated definitively.

Management of arteriovenous malformations in the elderly: a single-center case series and analysis of outcomes.

OBJECT Treatment of brain arteriovenous malformations (bAVMs) in the elderly remains a challenge for cerebrovascular surgeons. In this study the authors reviewed the patient characteristics, treatments, angiographic results, and clinical outcomes in 28 patients over 65 years of age who were treated at Henry Ford Hospital between 1990 and 2014. METHODS The bAVM database at the authors' institution was queried for records of elderly patients with bAVMs, and data regarding patient demographics, presenting symptoms, bAVM angioarchitecture, treatment modalities, angiographic results, clinical outcomes, and treatment complications were tabulated and analyzed. RESULTS There were 9 male (32%) and 19 female (68%) patients, with an average age ( ± SD) of 73.0 ± 6.95 years. The most common symptoms on presentation were hemorrhage (36%) and headaches (18%). The bAVMs were equally distributed between the supra- and infratentorial compartments. The most common Spetzler-Martin grade was II, observed in 57% of the patients. Eleven patients (39.3%) underwent resection, 4 patients (14.3%) received standalone radiation therapy, and 13 patients (46%) did not receive treatment or were managed expectantly. Four patients (14.3%) were lost to follow-up. Complete bAVM obliteration was achieved in 87% of the treated patients. None of the patients who received any form of treatment died; the overall mortality rate was 3.6%. CONCLUSIONS Surgical management of bAVMs in the elderly can result in complete obliteration and acceptable clinical outcomes.

Surgical Management of Giant Intracranial Arteriovenous Malformations: A Single Center Experience over 32 years.

OBJECTIVE: Treatment of giant intracranial arteriovenous malformations (gAVMs) is a formidable challenge for neurosurgeons and carries significant morbidity and mortality rates for patients compared with smaller AVMs. In this study, we reviewed the treatments, angiographic results, and clinical outcomes in 64 patients with gAVMs who were treated at Henry Ford Hospital between 1980 and 2012. METHODS: The arteriovenous malformation (AVM) database at our institution was queried for patients with gAVMs (≥ 6 cm) and data regarding patient demographics, presentation, AVM angioarchitecture, and treatments were collected. Functional outcomes as well as complications were analyzed. RESULTS: Of the 64 patients, 33 (51.6%) were female and 31 (48.4%) were male, with an average age of 45.7 years (SD ± 15.5). The most common symptoms on presentation were headaches (50%), seizures (50%), and hemorrhage (41%). The mean AVM size was 6.65 cm (range, 6-9 cm). Only 6 AVMs (9.4%) were located in the posterior fossa. The most common Spetzler-Martin grade was V, seen in 64% of patients. Of the 64 patients, 42 (66%) underwent surgical excision, 10 (15.5%) declined any treatment, 8 (12.5%) were deemed inoperable and followed conservatively, 2 (3%) had stand-alone embolization, 1 (1.5%) had embolization before stereotactic radiosurgery, and 1 (1.5%) received stereotactic radiosurgery only. Complete obliteration was achieved in 90% of the surgical patients. Mortality rate was 19% in the surgical cohort compared with 22% in the observation cohort (P = 0.770). CONCLUSIONS: Treatment of gAVMs carries significant morbidity and mortality; however, good outcomes are attainable with a multimodal treatment approach in carefully selected patients.

Prenatal Diagnosis of Congenital Dermal Sinus.

Background Congenital dermal sinus (CDS) is an uncommon form of spinal dysraphism. Although postdelivery identification in the neonate is aided by several associated physical examination findings, establishing this diagnosis prenatally has proven to be elusive. Case Report We present a case of CDS where the prenatal findings at 20 weeks gestation led to the diagnosis, which was confirmed postnatally. The associated protrusion of fibrotic membranes through the sinus tract helped in the identification of this lesion prenatally, but created confusion with a more common type of lesion, an open neural tube defect. This is the first case report in the literature describing prenatal diagnosis of fetal CDS. Conclusion Prenatal diagnosis with postnatal confirmation of CDS leads to early intervention, better long-term outcomes, and lesser complications.

Left temporal craniotomy for clipping of fusiform aneurysm of posterior cerebral artery.

Aneurysms of the posterior cerebral artery (PCA) are a distinct pathological entity and are surgically challenging. Fusiform aneurysms involving the PCA are quite rare and scarcely reported in the literature. In this video, we demonstrate the utility of the subtemporal approach to surgically reconstruct an unruptured, fusiform aneurysm of the left PCA, located at the junction of P3 and P4 segments. Curved clips were used to reconstruct the aneurysm such that flow was maintained in the parent vessel as well as distal branches. Postoperatively, the patient remained neurologically intact. The video can be found here: http://youtu.be/l7yzUPsaMc4.

Novel technique for cranial reconstruction following retrosigmoid craniectomy using demineralized bone matrix.

OBJECTIVE: A versatile neurosurgical approach, the retrosigmoid craniectomy (RS) has traditionally been associated with high rates of post-operative cerebrospinal fluid (CSF) leak, headaches, and aesthetic defects. We introduce a simple surgical strategy for bony cranial reconstruction designed to minimize peri-operative complications and improve cosmetic outcomes. METHODS: In accordance with the Institutional Review Board, the senior author's (G.M.M.) records were queried between 2006 and 2014. We identified 50 consecutive patients who underwent demineralized bone matrix (DBM)-augmented cranioplasty after RS for MVD (DBM group) and 92 consecutive patients in whom standard cranial reconstruction was undertaken using autologous bone chips only after RS for MVD (non-DBM group). Demographic and clinical information regarding the laterality of each operation, intra-dural drilling for petrous hyperostosis, method of dural closure, length of hospitalization, presence of post-operative headaches, and procedure-related complications were collected and analyzed. RESULTS: The DBM and non-DBM cohorts were well matched for age, laterality of procedure, surgical indications, primary versus revision surgery, intra-dural drilling of petrous hyperostosis, and dural closure techniques. Trigeminal neuralgia was the most common surgical indication (98.6%) in each cohort. Post-operatively, 15% of patients in non-DBM group experienced chronic headaches at the last follow-up compared to only 8% of the patients in the DBM group (p=0.21). The non-DBM patients also suffered more incisional pain in comparison to the DBM patients (7.6% vs. 0%, p=0.045). CONCLUSION: DBM-augmented reconstruction of posterior fossa defects resulted in low rates of post-operative headaches, better cosmetic outcomes, and represents a simple and effective cranioplasty option for skull base surgeons.

Spontaneous resolution of a flow-related ophthalmic-segment aneurysm after treatment of anterior cranial fossa dural arteriovenous fistula.

BACKGROUND: The natural history of proximal, feeding-artery aneurysms after successful obliteration of high-grade, anterior cranial fossa dural arteriovenous fistulas (dAVFs) has not been well documented. CASE DESCRIPTION: A 52-year-old Caucasian male presented with an unruptured anterior cranial fossa (dAVF) and an associated aneurysm. Cerebral angiography revealed a large, contralateral, carotid-ophthalmic segment aneurysm, enlarged feeding ophthalmic arteries, as well as cortical venous drainage. Successful surgical obliteration of the dAVF was undertaken to eliminate the risk of hemorrhage. CONCLUSION: The carotid-ophthalmic aneurysm regressed significantly after surgical obliteration of the dAVF and a follow-up, planned coiling procedure to address the carotid-ophthalmic aneurysm was abandoned. This represents the first reported case of a near complete, spontaneous resolution of an unruptured carotid-ophthalmic aneurysm associated with a high-grade anterior cranial fossa dAVF.

Management of perisylvian arteriovenous malformations: a retrospective institutional case series and review of the literature.

OBJECT: Sylvian arteriovenous malformations (sAVMs) are challenging lesions of the central nervous system. The natural history of these unique lesions as well as clinical outcomes following treatment of sAVMs has been limited to case series owing to the rarity of these lesions. The authors present their experience with sAVMs and review the literature. METHODS: In accordance with the Henry Ford Institutional Review Board, medical records of patients with sAVMs treated from 2000 to 2012 were reviewed. Clinical data were retrospectively collected to calculate pre- and posttreatment modified Rankin Scale scores for all patients. RESULTS: The authors identified 15 patients with sAVMs who received treatment. Of these, 12 were female and 3 were male, and the average age at presentation was 39.6 ± 12.94 years (± SD). Two patients (13.3%) had Spetzler-Martin Grade I lesions, 6 patients (40%) had Grade II lesions, 5 patients (33.3%) had Grade III lesions, and another 2 (13.3%) harbored Grade IV arteriovenous malformations (AVMs). According to the Sugita classification, 6 patients (40%) had medial lesions, 6 (40%) had lateral lesions, 2 (13.3%) had deep lesions, and 1 patient (6.67%) had a pure sAVM. Eight patients (53.3%) underwent stereotactic radiosurgery while 7 patients (46.7%) had microsurgical resection; 1 patient underwent surgical extirpation after incomplete response following radiosurgery. After treatment, 9 patients were unchanged from pretreatment (60%), 3 patients worsened, and 2 patients had improved functional outcome (20% and 13.3%, respectively). The authors' literature search yielded 348 patients with sAVMs, most of them harboring Spetzler-Martin Grade II and III lesions. Approximately 98% of the patients underwent resection with excellent outcomes. CONCLUSIONS: While the ideal choice of therapeutic modality for cerebral AVMs remains controversial in light of the recent publication of the ARUBA (A Randomized trial of Unruptured Brain AVMs) trial, a multidisciplinary treatment approach for the management of sAVMs can lead to acceptable neurological outcome.

Creating accountable care for carotid angioplasty and stenting: A multidisciplinary carotid revascularization board.

BACKGROUND: We tested the feasibility of a mandated multidisciplinary carotid revascularization board (MDCB) to review, approve and monitor all carotid artery and stenting (CAS) procedures and outcomes at our institution. METHODS: The board was composed of vascular surgeons, cardiologists, interventional neuroradiologists, neurosurgeons, and neurologists, who met weekly to facilitate an evidence-based, consensus recommendation to ensure appropriate CAS referral. RESULTS: The board successfully reviewed and continues to review and approve all CAS procedures at our center. Of the 69 patients considered high risk for standard surgical treatment, 42 patients were symptomatic and 27 patients were asymptomatic. Their mean age was 70.5-year-old and the median degree of stenosis was 79%. In the 74 procedures, periprocedural complications occurred at the following rates: 2.7% death, 2.7% major stroke, 2.7% minor stroke, and 2.7% myocardial infarction (MI) within 30 days of the procedure. At 1 year the primary endpoints of ipsilateral stroke and neurovascular-related death were observed in 8.1% and 2.7% of the patients, respectively. At mean follow-up of 21 months, 18.8% of the patients (13/69) had died (including all causes), and 14.5% (10/69) experienced stroke (including nontarget strokes). Target vessel revascularization was needed in 2.9% patients. CONCLUSIONS: A mandated multidisciplinary carotid revascularization board MDCB is feasible and potentially advantageous in real clinical practice. It establishes a model for accountable care by providing a mechanism for institutional oversight, credentialing operators, quality review, standardizing care, cost containment and eliminating the "subspecialty silo mentality."

Statement of Ethics in Neurosurgery of the World Federation of Neurosurgical Societies.

This Statement of Ethics in Neurosurgery was developed by the Committee for Ethics and Medico-Legal Affairs of the World Federation of Neurosurgical Societies to help neurosurgeons resolve problems in the treatment of individual patients and meet obligations to the larger society. This document is intended as a framework rather than a set of rules. It cannot cover every situation and should be used with flexibility. However, it is our intent that the fundamental principles enunciated here should serve as a guide in the day-to-day practice of neurosurgery.

Erlotinib therapy for central nervous system hemangioblastomatosis associated with von Hippel-Lindau disease: a case report.

There is a need for effective systemic therapy for central nervous system (CNS) hemangioblastomas (HBs). We report a case of erlotinib therapy for CNS HBs in a patient with von Hippel-Lindau disease, in whom the HBs were associated with diffuse leptomeningeal seeding. We provide the first report of paired serum and cerebrospinal fluid (CSF) levels of erlotinib while on standard dosing. The patient exhibited neurologic and imaging signs of recurrent CNS HBs and progressive leptomeningeal metastasis following surgery, radiation, and stereotactic radiosurgery. The patient was treated with erlotinib 150 mg daily. The patient achieved a minor response to erlotinib therapy, including clinical improvement, reduction in size of two enhancing brain lesions (one of which, however, proved at autopsy to be radiation necrosis) and stabilization of leptomeningeal enhancement. In addition, the CSF white count improved. The duration of response was 9 months. The median plasma and CSF levels of erlotinib while on treatment were 1146.06 and 247.83 ng/ml, respectively (CSF 21.6% of plasma). Erlotinib may have antitumor activity in CNS HBs.

Dural arteriovenous malformations of the skull base.

Dural arteriovenous malformations (AVMs) are interesting lesions, which can present as diagnostic and therapeutic challenges. Such AVMs were initially described as located solely in the dural venous sinuses, but during the last decade researchers have discovered them in other locations such as the tentorium and foramen magnum. It is understandable that they can develop in other locations because numerous arteriovenous shunts normally occur all over the dura. Early reports emphasize that they are congenital; however, some investigators have proposed that they are acquired lesions arising after sinus thrombosis and trauma. They also have variable clinical features. From 1975 to 2000 we treated 400 AVMs, of which 46 were dural. Of these 46 dural AVMs, 18 could be classified as skull base AVMs. We restricted the designation of skull base AVMs to those AVMs located in the tentorium or adjacent to bones of the skull base. Two of these AVMs actually had their vascular nidus located in the bone. The common dural sinus AVMs were excluded from this category. The presenting clinical features of these skull base AVMs ranged from headache and pulsatile tinnitus to intracranial hemorrhage. They were treated by a combination of endovascular and microsurgical treatment. The majority of patients had a good clinical outcome. Skull base dural AVMs are an interesting clinical entity. Their clinical course, treatment and final outcome are variable depending on their location. They should be managed by a multidisciplinary approach.

Stent-within-a-stent technique for the treatment of dissecting vertebral artery aneurysms.

Subarachnoid hemorrhage from dissecting vertebral artery aneurysms is a well-known phenomenon. With the advent of navigable intracranial stents, these aneurysms are now amenable to endovascular stent placement. However, immediate aneurysm obliteration is often not accomplished, and current covered stents have poor short-term patency rates. We report a series of three patients with intradural dissecting vertebral artery aneurysms treated with a novel endovascular stent-within-a-stent construct using currently available stent technology.

Carotid endarterectomy in patients with contralateral internal carotid artery occlusion without intraoperative shunting.

BACKGROUND: Controversy about the optimal method of performing a carotid endarterectomy (CEA) exists despite its widespread application and support from various randomized clinical trials. Many surgeons selectively or routinely use electroencephalography (EEG) monitoring as well as shunting when performing this operation. METHODS: We conducted this retrospective study to assess the maximum carotid clamp time without shunting or EEG monitoring during a CEA without the development of neurological deficits in an already compromised cerebral circulation. RESULTS: Fifteen consecutive patients who underwent CEAs between 1988 and 1999 met our criteria of angiographically documented ipsilateral internal carotid artery (ICA) stenosis with contralateral ICA occlusion. The patient presentations included asymptomatic (14%), transient ischemic attack (TIA) (50%), and stroke (36%). All patients were operated under general anesthesia without shunting and only 4 patients underwent EEG monitoring. On angiography, all 15 patients had ipsilateral ICA stenosis (70-99%) and contralateral occlusion. In 54% of patients, the vertebral arteries (VAs) were both patent, while in 46% of patients only 1 VA was patent. Eighty-five percent of patients had at least 1 patent anterior communicating (Pcomm) artery, while 15% had nonvisualized Pcomm arteries bilaterally. Of the 15 patients, 14 had a patent anterior communicating artery. The mean clamp time of the CCA was 18.5 minutes (range 14-30 minutes). None of the 15 patients had new neurological changes immediately postoperatively or during the 6 weeks of follow-up. CONCLUSION: We propose that shunting may not be necessary during CEA for high-grade stenosis with contralateral ICA occlusion, presumably because of adequate distal small vessel collaterals.