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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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Carotid endarterectomy should be considered for patients with symptoms of focal cerebral ischemia, when it can be performed with a combined morbidity and mortality below the annual risk of stroke (5 per cent). The experience with 815 carotid endarterectomies performed from 1979 to 1992 is presented. There were 530 (65 per cent) men and 285 (35 per cent) women of ages from 34 to 82 (median 65); risk factors included diabetes mellitus 196 (24 per cent), hypertension 554 (68 per cent), and smoking 570 (70 per cent). Clinical presentation consisted of transient ischemic attacks 464 (57 per cent), cerebral infarction with minimal neurological residual 228 (28 per cent), stroke in evolution 2 (0.2 per cent), and asymptomatic stenosis 121 (15 per cent). By Sundt's classification of medical risk the groups were: grade I, 106 (13 per cent); grade II, 350 (43 per cent); grade III, 357 (44 per cent); grade IV, 2 (0.2 per cent). All patients received endotracheal anesthesia. Thiopental (3-5 mg/kg) and lidocaine (1 mg/kg) were given for induction and at 15 minutes intervals during carotid cross-clamping. Intraluminal shunts were used in 14 (2 per cent). A conventional (open) endarterectomy was performed in 379 (46 per cent) and a limited endarterectomy (closed) in 436 (54 per cent). Complications included 8 (1 per cent) deaths, 24 (3 per cent) developed a major neurological deficit that persisted, 24 (3 per cent) had perioperative TIA's which resolved completely. Of the patients with preoperative neurological deficits, 32 (4 per cent) recovered. Therefore, at one month after surgery, 782 (96 per cent) were either as well or better than preoperatively.Of 483 (59 per cent) postoperative angiograms, 40 (5 per cent) showed an internal carotid artery occlusion. Six of these patients developed and immediate postoperative cerebral infarction and one died. Non-neurologic complications were: cardiac 40 (5 per cent), peripheral nerve 24 (3 per cent), and local wound problems 16 (2 per cent). A carotid endarterectomy can be performed safely when it is done with meticulous attention to detail and consistent surgical technique.

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