Liquid embolic surface area as a predictor of chronic subdural hematoma resolution in middle meningeal artery embolization.

BACKGROUND: Liquid embolic agents (LEAs) such as ethylene vinyl alcohol (EVOH) are utilized for middle meningeal artery embolization (MMAE) for chronic subdural hematomas (cSDH). LEAs may be advantageous for MMAE as they are permanent and can penetrate the microvasculature of the subdural membranes. LEA surface area (SA) can quantify this penetration. The segmentation of LEA SA is not described in the literature and may be of interest in refining MMAE technique. METHODS: We retrospectively collected computerized tomography (CT) scans from 74 patients (with 95 cSDH) who underwent first-line MMAE with EVOH. Non-contrast head CTs were acquired pre-embolization, immediately post-embolization and at 1-, 3-, and 6 month follow-up. A 3D-Slicer was used to segment hematoma volumes and the liquid embolic cast. We hypothesized that greater LEA SA would be correlated with greater improvements in cSDH volumetric resolution. RESULTS: There was significant resolution in cSDH volumes over the follow-up period compared to preoperative volume (p<0.0001). The LEA SA was significantly correlated with the rate of cSDH resolution at 3 months (R2=0.08, p=0.03), and 6 months (R2=0.14, p=0.01). CONCLUSIONS: The correlation of LEA surface area with hematoma resolution at 3-months and 6-months suggests greater LEA penetration may improve radiographic outcomes. This study uniquely provides a quantitative radiological perspective on the effect of LEA penetration on cSDH resolution.

Modulating microbiome-immune axis in the deployment-related chronic diseases of Veterans: report of an expert meeting.

The present report summarizes the United States Department of Veterans Affairs (VA) field-based meeting titled "Modulating microbiome-immune axis in the deployment-related chronic diseases of Veterans." Our Veteran patient population experiences a high incidence of service-related chronic physical and mental health problems, such as infection, irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), various forms of hematological and non-hematological malignancies, neurologic conditions, end-stage organ failure, requiring transplantation, and posttraumatic stress disorder (PTSD). We report the views of a group of scientists who focus on the current state of scientific knowledge elucidating the mechanisms underlying the aforementioned disorders, novel therapeutic targets, and development of new approaches for clinical intervention. In conclusion, we dovetailed on four research areas of interest: 1) microbiome interaction with immune cells after hematopoietic cell and/or solid organ transplantation, graft-versus-host disease (GVHD) and graft rejection, 2) intestinal inflammation and its modification in IBD and cancer, 3) microbiome-neuron-immunity interplay in mental and physical health, and 4) microbiome-micronutrient-immune interactions during homeostasis and infectious diseases. At this VA field-based meeting, we proposed to explore a multi-disciplinary, multi-institutional, collaborative strategy to initiate a roadmap, specifically focusing on host microbiome-immune interactions among those with service-related chronic diseases to potentially identify novel and translatable therapeutic targets.

Role of artificial intelligence and machine learning in the diagnosis of cerebrovascular disease.

Introduction: Cerebrovascular diseases are known to cause significant morbidity and mortality to the general population. In patients with cerebrovascular disease, prompt clinical evaluation and radiographic interpretation are both essential in optimizing clinical management and in triaging patients for critical and potentially life-saving neurosurgical interventions. With recent advancements in the domains of artificial intelligence (AI) and machine learning (ML), many AI and ML algorithms have been developed to further optimize the diagnosis and subsequent management of cerebrovascular disease. Despite such advances, further studies are needed to substantively evaluate both the diagnostic accuracy and feasibility of these techniques for their application in clinical practice. This review aims to analyze the current use of AI and MI algorithms in the diagnosis of, and clinical decision making for cerebrovascular disease, and to discuss both the feasibility and future applications of utilizing such algorithms. Methods: We review the use of AI and ML algorithms to assist clinicians in the diagnosis and management of ischemic stroke, hemorrhagic stroke, intracranial aneurysms, and arteriovenous malformations (AVMs). After identifying the most widely used algorithms, we provide a detailed analysis of the accuracy and effectiveness of these algorithms in practice. Results: The incorporation of AI and ML algorithms for cerebrovascular patients has demonstrated improvements in time to detection of intracranial pathologies such as intracerebral hemorrhage (ICH) and infarcts. For ischemic and hemorrhagic strokes, commercial AI software platforms such as RapidAI and Viz.AI have bene implemented into routine clinical practice at many stroke centers to expedite the detection of infarcts and ICH, respectively. Such algorithms and neural networks have also been analyzed for use in prognostication for such cerebrovascular pathologies. These include predicting outcomes for ischemic stroke patients, hematoma expansion, risk of aneurysm rupture, bleeding of AVMs, and in predicting outcomes following interventions such as risk of occlusion for various endovascular devices. Preliminary analyses have yielded promising sensitivities when AI and ML are used in concert with imaging modalities and a multidisciplinary team of health care providers. Conclusion: The implementation of AI and ML algorithms to supplement clinical practice has conferred a high degree of accuracy, efficiency, and expedited detection in the clinical and radiographic evaluation and management of ischemic and hemorrhagic strokes, AVMs, and aneurysms. Such algorithms have been explored for further purposes of prognostication for these conditions, with promising preliminary results. Further studies should evaluate the longitudinal implementation of such techniques into hospital networks and residency programs to supplement clinical practice, and the extent to which these techniques improve patient care and clinical outcomes in the long-term.

Modeling of soiling losses on photovoltaic module based on transmittance loss effect.

The photovoltaic modules are mostly installed outdoors, exposing them to different conditions. These conditions significantly affect their performance. One of the most influential factors on photovoltaic modules is the soiling phenomenon from dust deposition. Dust deposition on the surface of the modules causes transmittance loss. Some studies in different parts of the world have tried to find mathematical correlations between particulate deposition and transmittance. These correlations are a function of dust characteristics and environmental factors. This study proposes a new methodology to mathematically combine the photovoltaic model and transmittance loss correlations. The proposed model could examine and predict the effect of soiling on photovoltaic modules' performance. Three photovoltaic modules with different capacities are selected. Using the proposed model, they are modeled by assuming clean and dirty photovoltaic surfaces depending on the installation conditions. This study is based on actual data from the center of Tehran, located at 35° 41' north latitude and 51° 23' east longitude for 12 months in the year 2020. The module's performance was investigated in the presence of dust. The presented results are validated by comparing them with other studies. The results show that the soiling effect is not dependent on the modules' capacity.

Slow-Closing Clip for the Treatment of Nonsaccular Vertebrobasilar Aneurysms: A Retrospective Case Series.

OBJECTIVE: Vertebrobasilar artery nonsaccular aneurysms (VBANSAs) are associated with a 13% annual mortality. Revascularization and flow diversion are life-saving options in select cases; technical failures and rapid hemodynamic changes may contribute to unwanted outcomes. We describe a technique and report clinical outcomes of patients treated with an experimental slow-closing clip (SCC). METHODS: An experimental SCC was created to gradually close the parent artery of aneurysms. Clinical, radiographic, and outcome data from patients with VBANSAs who underwent experimental treatment with the SCC were retrospectively analyzed. RESULTS: Among 10 patients (7 men; mean age, 49.5 years; range, 18-73 years), 6 presented with mass effect symptoms, 1 with ischemic stroke, 2 with subarachnoid hemorrhage, and 1 with hydrocephalus. Five patients underwent revascularization plus SCC application, and 5 were treated with SCC alone. The mean follow-up was 6.7 years. The expected mortality among patients with unruptured VBANSAs with previous treatment options in this period was 52.7%, whereas the observed rate was 20%. Four patients died within 12 months after treatment. Causes of death were brainstem ischemic stroke, poor-grade subarachnoid hemorrhage, poor clinical presentation, and unknown. Six patients were alive at last follow-up, with unchanged or improved modified Rankin Scale scores. Mortality was associated with posterior-projecting aneurysms and late-stage treatment. CONCLUSIONS: In this small case series, use of SCC overcame the natural history of VBANSAs when treatment timing and aneurysm anatomy were suitable. The SCC potentially favors aneurysm thrombosis and collateral reactivation. More studies are necessary to better develop the SCC.

A New Scoring System for Prediction of Underlying Vascular Pathology in Patients with Intracerebral Hemorrhage: The Modified Secondary Intracerebral Hemorrhage Score.

BACKGROUND: Secondary intracerebral hemorrhage (SICH) score is used to predict risk of intracranial hemorrhage (ICH) associated vascular lesions. However, it has low clinical utility in identifying patients without need for neurovascular imaging. This study aims to develop a modified scoring system to capture patients with low risk of underlying vascular pathology, thereby decreasing need for vascular imaging and its associated morbidity. METHODS: A retrospective analysis of 994 patients with atraumatic ICH over 8 years was conducted, excluding known underlying pathology, subarachnoid hemorrhage, or lack of vascular imaging. Using a multivariate logistic regression model, independent predictors of vascular pathology were identified and utilized toward developing a modified Secondary Intracerebral Hemorrhage (mSICH) score. RESULTS: Of 575 patients identified, 60 (10.4%) had underlying vascular etiology. Statistically significant predictors of vascular pathology included age; female sex; admission systolic blood pressure <160 mm Hg; locations other than basal ganglia, thalamus, pons, or midbrain; presence of high-risk imaging features; and proximity to large vessel-containing cisterns. The mSICH score correlated with an increasing incidence of vascular pathology [0-1 (0%), 9 (4.3%), 12 (9.7%), 21 (40.4%), 6 (33.3%), 8 (88.9%), and 4 (100%)] and had a significantly higher number of patients receiving scores with 0% incidence of vascular lesions compared with the SICH score [159 (27.6%) versus 12 (2.1%); P < 0.001)]. CONCLUSIONS: The mSICH score can more accurately predict risk of underlying vascular pathology of ICH and identify patients with lowest risk of vascular pathology. This may minimize the cost and associated risks of invasive cerebrovascular imaging.

Single-stage planning for total cure of grade III-V brain arteriovenous malformations by embolization alone or in combination with microsurgical resection.

PURPOSE: There are no established guidelines for treatment of Spetzler-Martin grade III-V brain arteriovenous malformations (bAVMs). The purpose of this study is to report our institutional experience in total obliteration/eradication of grade III-V bAVMs by single-stage planning of embolization combined with microsurgical resection when necessary. METHODS: All patients harboring Spetzler-Martin (S-M) grade III-V bAVMs treated with single-stage planning between January 2006 and January 2018 were retrospectively reviewed. This treatment paradigm is applicable only to surgically accessible bAVMs and does not include deep-seated bAVMs. Indications for treatment, clinical presentation, imaging characteristics, and treatment outcomes were analyzed. Outcomes were assessed based on modified Rankin Scale. RESULTS: A total of 31 patients were identified. Seventeen patients (54.8%) presented with hemorrhage, 10 (32.3%) with seizures, 3 (9.7%) with headaches, and 1 (3.2%) with progressive neurological deficit. Based on S-M grading system, 25 patients (80.6%) harbored grade III bAVM, 5 patients had grade IV bAVMs (16.1%), and 1 patient (3.2%) had a grade V bAVM. There were no treatment-related complications in 24/31 (77.4%) patients. Of the total of seven patients with complications, four patients had clinical deterioration. The long-term (> 6-month), non-disabling morbidity (mRS ≤ 2) rate was 6.5%. The long-term, disabling morbidity rate was 3.2% with a mortality of 3.2%. Complete angiographic obliteration was achieved in 30/31 (96.8%) patients. CONCLUSION: Single-stage treatment strategy can be considered as an alternative to multistage embolization prior to surgery in grade III-V bAVMs. In this study, a high rate of total obliteration with relatively low rates of permanent morbidity and mortality was achieved.

Intracranial Vertebral Artery Aneurysms: Clinical Features and Outcome of 190 Patients.

BACKGROUND: Vertebral artery (VA) aneurysms comprise approximately one-third of posterior circulation aneurysms. They are morphologically variable, and located critically close to the cranial nerves and the brainstem. We aim to represent the characteristics of these aneurysms and their treatment, and to analyze the outcome. METHODS: We reviewed retrospectively 9709 patients with intracranial aneurysms. Of these, we included 190 with aneurysms at the VA or VA-posterior inferior cerebellar artery junction. These patients were treated in the Department of Neurosurgery, Helsinki, Finland, between 1934 and 2011. RESULTS: The 190 patients had 193 VA aneurysms, among which 131 (68%) were ruptured. The VA aneurysm caused a mass effect in 7 and ischemia in 2 patients. Compared to 4387 patients with a ruptured aneurysm in other locations, those with a VA aneurysm were older, their aneurysms were more often fusiform, and more often caused intraventricular hemorrhages. Among surgically treated aneurysms, clipping was the treatment in 91 (88%) saccular and 11 (50%) fusiform aneurysms. Treatment was endovascular in 13 (9%), and multimodal in 6 (4%) aneurysms. Within a year after aneurysm diagnosis, 53 (28%) patients died. Among the survivors, 104 (93%) returned to an independent or to their previous state of life; only 2 (2%) were unable to return home. CONCLUSIONS: Microsurgery is a feasible treatment for VA aneurysms, although cranial nerve deficits are more common than in endovascular surgery. Despite the challenge of an often severe hemorrhage, of challenging morphology, and risk for laryngeal palsy, most patients surviving the initial stage return to normalcy.

Augmentation of N-butyl cyanoacrylate embolization of cranial, head, and neck tumors by simultaneous infusion of 5% dextrose solution.

BACKGROUND: N-Butyl cyanoacrylate (NBCA) is an adhesive liquid embolic agent widely used for embolization of cranial, head and neck tumors. Adequate distal penetration of NBCA into vessels with the smallest possible diameter, while preventing its reflux, is still a challenge, even in experienced hands. Simultaneous infusion of 5% dextrose in water solution (D5W) through the guiding catheter has been described before as a technique for improving embolization of dural arteriovenous malformations. OBJECTIVE: To describe our experience with a modified D5W guide catheter push technique during embolization of hemorrhagic cranial, head and neck tumors. The embolization technique and pitfalls which might lead to complications are discussed in detail. MATERIALS: A retrospective series of 20 patients treated with the D5W push technique during embolization of cranial, head and neck lesions between 2007 and 2013 is presented. The goal of embolization was preoperative or palliative embolization of hemorrhagic tumors. Localization and histopathologic diagnosis of lesions, concentration of NBCA used, subsequent surgical treatment, intraoperative blood loss, and complications were evaluated. RESULTS: A total of 44 arterial pedicles were embolized during 22 treatment sessions. Adequate embolization of the lesions was achieved in all cases. Transient ischemic attack due to atheroma embolization (from the aorta) was seen in one patient (4%). Persistent vascularity of tumor associated with minimal intraoperative bleeding was reported in one patient (4%). Recurrence of epistaxis was reported in two patients diagnosed with Osler-Weber-Rendu syndrome. CONCLUSIONS: The D5W push technique during NBCA embolization of cranial, head and neck tumors is a safe and effective method to enhance penetration of the embolizing agent.

Distal posterior inferior cerebellar artery aneurysms: clinical features and outcome of 80 patients.

OBJECTIVE: Aneurysms of the posterior inferior cerebellar artery (PICA) distal to its origin are rare. Beside their rarity, their treatment is challenged by a high proportion of fusiform aneurysms, torturous course of PICA, and often severe bleeding. Our aim is to represent the characteristics of these aneurysms and their treatment, as well as to analyze outcome. METHODS: We reviewed retrospectively 80 patients with PICA aneurysms who were treated at the Department of Neurosurgery, Helsinki, Finland. RESULTS: The 80 patients had altogether 91 distal PICA aneurysms. Subarachnoid hemorrhage occurred in 74 (93%), and the distal PICA aneurysm was ruptured in 68 (85%). Compared with aneurysms at other locations, distal PICA aneurysms were smaller, more often fusiform, and more often caused an intraventricular hemorrhage as well as rebleeding. Modified surgical techniques (trapping, wrapping, proximal occlusion, resection, coagulation) were used in 10 (32%) fusiform and in 3 (6%) saccular aneurysms. Revascularization was needed in 3 (4%) cases. One aneurysm was primarily embolized. Within a year after aneurysm diagnosis, 18 patients had died. Among survivors, most returned to independent or previous state of living: 52 (91%); only 1 patient was unable to return home. CONCLUSIONS: Microsurgery is a feasible treatment for distal PICA aneurysms. Despite the challenge of often severe hemorrhage, wide-necked aneurysms, and some risk for laryngeal palsy, most patients surviving the initial stage return to normal life. Because of the greater number of rebleedings than for aneurysms at other locations, immediate treatment is crucial.

Seventy aneurysms of the posterior inferior cerebellar artery: anatomical features and value of computed tomography angiography in microneurosurgery.

OBJECTIVE: Aneurysms at the junction of the vertebral artery (VA) and posterior inferior cerebellar artery (PICA) are relatively rare. Their treatment is challenged by the diverse anatomy of the VA and PICA, close involvement of the PICA in the aneurysm neck, and scant space deep in the posterior fossa next to the cranial nerves, brain stem, and obstructing structures of the skull base. Computed tomography angiography (CTA) visualizes bony structures in addition to the vasculature, and being noninvasive and easily available, it can serve for planning microsurgical treatment. We analyzed the anatomy of PICA aneurysms imaged by CTA to promote planning the treatment. METHODS: We examined the CTA images of 70 consecutive patients with a saccular PICA aneurysm who were all treated in the Department of Neurosurgery, Helsinki, Finland, 2001 to 2011. RESULTS: Each of the 70 patients had 1 aneurysm at the VA-PICA junction. The proportion of small aneurysms (<7 mm) was high, 67%. The dome-to-neck ratio was <1.2 in 24 (34%) of the aneurysms. In the coronal view, 58 (83%) aneurysms projected cranially, and only 2 (3%) caudally. The aneurysms were located from 1 mm below the foramen magnum to 31 mm above it, most arising at the level of the jugular tubercle. The median distance to the aneurysm from the midline was 6 mm, ranging from 7.5 mm contralateral to the origin of the parent artery to 14 mm ipsilateral. Compared with the right VA, the left VA was larger, it harbored the most aneurysms, and its aneurysms were more often ruptured. CONCLUSIONS: Relation of PICA aneurysms to skull base structures is highly variable; the aneurysms can also be extracranial, or lie on the site of the skull contralateral to the origin of the parent artery. These anatomical variations demand meticulous study of the angiography in each individual case, especially before surgical treatment of the aneurysm.

Patient selection for endovascular treatment of intracranial aneurysms.

With recent advancement in medical imaging, techniques, and endovascular tools more patients are diagnosed with unruptured intracranial aneurysms. The main aim of offering aneurysm treatment is to ameliorate the risk of future aneurysm bleeding, while not posing additional risks on the patient from the treatment itself. We discuss in this paper our approach of selecting patients for treatment (simple coiling, balloon-assisted, stent-assisted, vessel sacrifice, or flow-divertion stents). Our decision-making is based on the published data and our center experience. Risks of all option are compared to each other and weighed against natural history of intracranial aneurysms. In this paper, literature is cited and case illustrations are presented to support this approach. Factors that affect our decision-making are aneurysm location, presentation, size, aneurysm geometry, parent vessel anatomy, and relevant co-morbidities.

Balloons in endovascular neurosurgery: history and current applications.

The use of balloons in the field of neurosurgery is currently an essential part of our clinical practice. The field has evolved over the last 40 years since Serbinenko used balloons to test the feasibility of occluding cervical vessels for intracranial pathologies. Since that time, indications have expanded to include sacrificing cervical and intracranial vessels with detachable balloons, supporting the coil mass in wide-necked aneurysms (balloon remodeling technique), and performing intracranial and cervical angioplasty for atherosclerotic disease, as well as an adjunct to treat arteriovenous malformations. With the rapid expansion of endovascular technologies, it appears that the indications and uses for balloons will continue to expand. In this article, we review the history of balloons, the initial applications, the types of balloons available, and the current applications available for endovascular neurosurgeons.

The bihemispheric posterior interior cerebellar artery: anatomic variations and clinical relevance in 11 cases.

PURPOSE: Although the anatomic course of the posterior interior cerebellar artery (PICA) is variable, it is thought to be very rare for the artery to cross midline, with an estimated incidence of 0.1%. Bihemispheric PICA crosses midline and typically serves both PICA territories. METHODS: We present 11 cases of bihemispheric PICA discovered from retrospective angiogram review, the largest to date reported in the literature. RESULTS: Five cases were the typical bihemispheric PICA pattern, three were bihemispheric with distal vertebral hypoplasia, two cases were the vermian type, and one was atypical, with the PICA feeding a contralateral cerebellar arteriovenous malformation (AVM). The branching point to the contralateral hemisphere always occurred distal to the ascending tonsillar loop and all true bihemispheric variants had contralateral PICA aplasia. CONCLUSIONS: The true incidence of this variant may be much higher than previously thought (3.6% in the current series), and has relevance for cerebrovascular disease, including aneurysm, AVM, and ischemic stroke. Neuroradiologists, neurologists, and neurosurgeons should be aware of this potential variant.

Emergence of a high-grade sarcoma in a recurrent meningioma: malignant progression or collision tumor?

Anaplastic meningiomas that resemble sarcomas often reveal clues to their meningothelial differentiation or develop in a plausible setting that confirms their meningothelial origin. Malignant mesenchymal neoplasms without obvious evidence of meningothelial differentiation or origin are more likely to be true primary or metastatic sarcomas. Because of their clinical and biological differences, it is important to distinguish anaplastic meningioma from a sarcoma. We present a 67-year-old woman with multiple meningiomas, who developed a high-grade spindle cell tumor 6 months after the resection of a World Health Organization grade I meningioma. It was not clear whether this tumor represented a malignant transformation of meningioma or a primary sarcoma. Malignant transformation of a meningioma is exceptional within this short period and a coexisting sarcoma and meningioma are equally uncommon. Even though these malignant neoplasms are rare in general, they appear to be more prevalent in patients with multiple meningiomas including those with neurofibromatosis type 2.

Surgical treatment of trigonocephaly: technique and long-term results in 48 cases.

OBJECT: The authors present their experience in the surgical treatment of metopic synostosis by orbital bandeau remodeling and frontal bone rotation. The pitfalls and advantages of the surgical technique are discussed, along with the long-term clinical results in 48 consecutive cases. METHODS: Forty-eight consecutive patients in whom trigonocephaly was diagnosed between 1990 and 2009 were treated with frontal bone rotation and frontoorbital bandeau remodeling. Of these patients, 38 (79%) were boys and 10 (21%) were girls. The age at the time of surgical treatment ranged between 4 and 42 months (mean ± SD 11.4 ± 8.7 months). The average follow-up period was 5.5 ± 4.2 years (range 5 months-19 years). The preoperative and latest postoperative photographs of the patients were evaluated for the following features: 1) shape of the forehead; 2) hypotelorism; and 3) temporal depression. Scores of 0, 1, or 2 were assigned for each item: 0 was normal, 1 meant moderate deformity, and 2 denoted severe deformity. RESULTS: In the early postoperative period, no complications were documented. The average hospitalization period was 4 days. Follow-up radiographs or 3D CT scans were obtained at regular intervals. The mean preoperative scores for the evaluated items were 1.38 ± 0.49 for the shape of the forehead, 1.33 ± 0.48 for hypotelorism, and 1.7 ± 0.46 for the temporal depression. The mean postoperative scores were 0.06 ± 0.24 for the shape of the forehead, 0.21 ± 0.4 for hypotelorism, and 0.67 ± 0.48 for the temporal depression. Overall, the total preoperative score dropped from 4.4 to 0.93 postoperatively (p < 0.05). All the patients were contented with the cosmetic results. CONCLUSIONS: Early detection and treatment of metopic suture synostosis has a significant, favorable influence on the outcomes. Good understanding of the structural abnormality and the pathophysiological mechanisms of the possible complications is very important for performing proper surgical reconstruction.

Risk of hemorrhage in patients with untreated Spetzler-Martin grade IV and V arteriovenous malformations: a long-term follow-up study in 63 patients.

BACKGROUND: Treatment of Spetzler-Martin Grade IV and V brain arteriovenous malformations (ie, high-grade AVMs) carries a high risk of morbidity and even mortality. However, little is known about the behavior of these lesions if left untreated. OBJECTIVE: To investigate the natural history of patients with high-grade AVMs. METHODS: Patients with untreated high-grade AVMs admitted to our center between 1952 and 2005 were followed from admission until death, AVM rupture, or initiation of treatment. Rates of rupture and various risk factors were analyzed using Kaplan-Meier life table analyses and Cox proportional hazards models. Functional outcome was assessed 1 year after possible AVM rupture using the Glasgow Outcome Scale. RESULTS: Sixty-three patients with a mean follow-up time of 11.0 years (range, 1 month to 39.6 years) were identified. Twenty-three patients (37%) experienced a subsequent rupture. The average annual rate of rupture was 3.3%. In patients with hemorrhagic presentation, the annual rate was 6.0%, compared to 1.1% in patients with unruptured AVMs (P = .001, log-rank test; hazard ratio, 5.09 [1.40-18.5, 95% CI]; P = .013, multivariate Cox regression model). One year after the first subsequent rupture, 6 patients (26%) had died, and 9 (39%) had moderate or severe disability. CONCLUSION: Untreated high grade AVMs presenting with hemorrhage have a significant risk of subsequent rupture, and their rupture carries a higher risk of case fatality and permanent morbidity than AVMs in general. The risks associated with their treatment should be appraised in light of perilous natural history.

Lateral tethering intraspinal lipoma with scoliosis.

The authors present an unusual case of an intradural lipoma at the thoracolumbar level causing lateral tethering of the spine, with complicated scoliosis. A 6-year-old girl was admitted with progressive change in posture detected by her parents. Thoracolumbar scoliosis was detected by physical examination and X-ray studies. Spinal magnetic resonance imaging revealed an intradural lipoma and right lateral tethering of the spine at the upper lumbar level. After surgical release of lateral tethering and resection of the lipoma, fusion was performed by the orthopedic surgery team. Radiological and intraoperative findings of this extremely rare case are discussed.

Microscope integrated indocyanine green video-angiography in cerebrovascular surgery.

Microscope integrated indocyanine green video-angiography (ICG-VA) is a new technique for intraoperative assessment of blood flow that has been recently applied to the field of Neurosurgery. ICG-VA is known as a simple and practical method of blood flow assessment with acceptable reliability. Real time information obtained under magnification of operating microscope has many potential applications in the microneurosurgical management of vascular lesions. This review is based on institutional experience with use of ICG-VA during surgery of intracranial aneurysms, AVMs and other vascular lesions at the Department of Neurosurgery at Helsinki University Central Hospital.