A case of two pial arteriovenous fistulas with giant venous pouches treated by endovascular coil embolization: Therapy with and without anticoagulation

BACKGROUND

Endovascular coil embolization of pial arteriovenous fistulas (AVF) has been reported as an effective treatment. However, venous thrombosis and intracranial hemorrhage developing after endovascular occlusion of a pial AVF have not been adequately reported.

CASE DESCRIPTION

A 37-year-old man presented with left middle cerebral artery (MCA) AVF and right posterior cerebral artery (PCA) AVF with giant venous pouches. Staged endovascular coil embolization was performed. The MCA AVF was completely occluded by coils at the first stage. Intravenous heparin (3000 IU) was administered during the procedure, and then low molecular weight heparin (subcutaneous injection, 0.4 mL/12 hours) was administered for two days. The PCA AVF was near completely occluded by coils without anticoagulation therapy at the second stage. Rapid progressive venous thrombosis and intracranial hemorrhage were confirmed by computerized tomography brain scan postoperatively, and the patient was then transferred to the neurological intensive care unit for further treatment. Finally, the patient recovered well at the five-month follow-up.

CONCLUSIONS

Endovascular occlusion of a high-flow pial AVF with a giant venous pouch resulting in significant blood stasis could precipitate thrombosis in the venous system. Further studies are required to establish whether anticoagulation therapy is necessary.

Cerebral proliferative angiopathy: Clinical, angiographic features and literature review

PURPOSE

Here we present our experience with five cerebral proliferative angiopathy (CPA) patients to better delineate the clinical and angiographic features as well as the treatment selection of this disease.

METHODS

Between October 2008 and October 2012, five consecutive patients diagnosed with CPA were admitted to our department in our hospital. All the five patients received magnetic resonance imaging, digital subtraction angiography, and positron emission computed tomography (PET) to definitively confirm this disease. We also collected 15 previously published instances of CPA to analyze the characteristics of this rare entity.

RESULTS

As to the five patients, three were female and two were male, between the ages of 4 and 52 years with a mean age of 24.8±20.6 years. The PET results showed that perfusion was decreased over the affected hemispheres in all five patients. As to the treatment, only one patient received encephalo-duro-arterio-synangiosis (EDAS) revascularization surgery. The other four patients were conservatively observed. During the follow-up period (range 3-6 years, mean 4±1.9 years), the patient who underwent EDAS surgery manifested relief of clinical symptoms. In the conservative series, the symptoms in two patients aggravated and suffered permanent neurologic deficits.

CONCLUSION

CPA is a rare entity. Natural history has showed this disease is not stable and may progress at a certain time point. The EDAS procedure may be a treatment for CPA-related oligemia since there is currently little data and follow-up available.

Flow-diverter devices in the treatment of intracranial aneurysms: A meta-analysis and systematic review

OBJECTIVE

The purpose of this report was to discuss the overall limitations, safety and efficacy of flow-diverter stenting for intracranial aneurysms.

METHODS

The authors performed a meta-analysis from January 2009 to September 2014 using the terms "flow diverter" and "intracranial aneurysms." Additional studies were identified through references in each reviewed article. Data extraction, performed independently by the authors, included demographic data, technical and clinical complications, morbidity and mortality, aneurismal occlusion rates related to flow-diverter devices. The analysis was performed using a fixed effect.

RESULTS

Twenty-nine studies with 1524 patients and three to 62 months of follow-up were identified for analysis. The overall technical failure and complication rate was 9.3% (95% CI 6%-12.6%). The rate of procedure-related complication was 14% (95% CI 10.2%-17.9%) and 6.6% (95% CI 4%-9.1%) for morbidity and mortality. Fusiform, dissecting and circumferential aneurysm (OR 3.10, 95% CI 0.93-10.37) were significant risk factors for technical failure and complication. Posterior circulation location (OR 4.03, 95% CI 2.45-6.61), peripheral location (OR 2.74, 95% CI 1.52-4.94) and fusiform, dissecting and circumferential aneurysm (OR 1.95, 95% CI 1.15-3.30) were statistically significant risk factors for procedure-related complications. Posterior circulation location (OR 4.39, 95% CI 2.44-7.90) and peripheral location (OR 3.64, 95% CI 1.74-7.62) were statistically significant risk factors for morbidity and mortality.

CONCLUSIONS

Fusiform, dissecting and circumferential aneurysm, posterior circulation and peripheral locations have greater procedure-related complications.

Hemorrhagic Moyamoya Disease in Children: Clinical, Angiographic features, and Long-Term Surgical Outcome

BACKGROUND AND PURPOSE

Here, we describe the clinical, angiographic characteristics, and long-term surgical outcome of hemorrhagic moyamoya disease in children.

METHODS

We retrospectively collected 374 consecutive children with moyamoya disease (hemorrhagic 30 and ischemic 344) between 2004 and 2012 in our hospital. The clinical and radiological characteristics of the hemorrhagic patients were retrospectively described and analyzed. All the hemorrhagic patients underwent encephalo-duro-arterio-synangiosis procedure. Digital subtraction angiography was performed to evaluate the efficacy of vascularization. Clinical follow-up outcomes were obtained through clinical visits, telephone, or letter interview.

RESULTS

In our study, the ratio of female to male patients in the hemorrhagic group was significantly higher than the ischemic group (2:1 versus 0.9:1; P<0.05). The most frequent hemorrhagic location was intraventricular hemorrhage (n=22, 73%). In addition, significantly greater dilatation of the anterior choroidal artery and the posterior communicating artery were seen in the hemorrhagic group (P<0.05). Good or fair vascularization were observed in all the 15 children with digital subtraction angiography follow-up. Clinical outcomes showed that 25 of 30 (83%) patients had no disability (modified Rankin scale score, 0 and 1); 1 patient (3.3%) died of recurrent hemorrhagic stroke.

CONCLUSIONS

The presence of anterior choroidal artery and posterior communicating artery dilation may be associated with the bleeding episode in the children with hemorrhagic moyamoya disease. The encephalo-duro-arterio-synangiosis surgery can effectively increase the cerebral blood flow in children, which may decrease the incidence of recurrent hemorrhage.

Occult Pulsatile Tinnitus in Association with a Prominent Vein of Hypoglossal Canal: Two Case Reports

The pathway of the vein of hypoglossal canal has not been mentioned in venous origin pulsatile tinnitus. We wished to clarify the possible complications related to this venous variant. We described 2 rare cases of troublesome pulsatile tinnitus associated with prominent vein of hypoglossal canal, which communicates with the jugular bulb and the marginal sinus. Both cases were successfully treated by positioning a stent across the vein of hypoglossal canal and jugular bulb. The 2 present clinical cases represent the first report of such a condition. The therapeutic decision-making is discussed in relation to the persistent pulsatile tinnitus and the etiopathologic hypothesis put forward.

Stent-Assisted Coil Embolization of a Transverse-Sigmoid Sinus Diverticulum Presenting with Pulsatile Tinnitus

When tinnitus is pulse-synchronous, a vascular etiology is suggested. We present a case of persistent and troublesome pulsatile tinnitus caused by a transverse-sigmoid sinus diverticulum that was endovascularly treated with stent-assisted coiling. A 39-yearold woman presented with a 4-year history of progressive pulsatile tinnitus involving the right ear. Slight pulsatile bruit was heard on the right mastoid bone by auscultation. Cerebral angiography demonstrated a diverticulum of the transverse-sigmoid sinus. The procedure was performed with an 8F guiding catheter (Cordis, USA) catheterized into the right sigmoid sinus. The diverticulum was completely coiled following deployment of a 5.5 mm-50 mm Leo stent. This patient awakened without any neurological deficit and with immediate resolution of her tinnitus. This case report describes a stent-assisted coil embolization of venous sinus diverticulum, which provides immediate resolution of pulsatile tinnitus.

Proposal of Classification of Aneurysms Coexisting with AVM and Possible Treatment Strategies

AIM

To describe the classification of aneurysms coexisting with arteriovenous malformations (AVMs) and their endovascular treatment.

MATERIAL AND METHODS

Based on the basis of radiological findings and clinical features, 59 aneurysms coexisting with AVMs were classified into four different types: intranidal, flow-related (proximal and distal), and unrelated. These aneurysms were treated by endovascular techniques with or without AVM embolization. Clinical outcome was assessed using the modified Rankin Scale (mRS).

RESULTS

59 aneurysms coexisting with AVMs were found in 39 patients. There were 11 unrelated aneurysms, 18 proximal flow-related aneurysms, 11 distal flow-related aneurysms and 19 intranidal aneurysms. In the 11 unrelated aneurysms, 4 were caused subarachnoid hemorrhage. In 11 distal flow-related aneurysms near the AVM, 7 caused a major hemorrhage. Six of the 19 intranidal aneurysms presented with hemorrhage. In contrast, only 3 of the 14 proximal flow-related aneurysms on major feeding arteries caused hemorrhage.

CONCLUSION

Aneurysms coexisting with AVMs could be classified into four types and this classification may provide a rationale for endovascular treatment.

Anatomic variations of internal jugular vein, inferior petrosal sinus and its confluence pattern: Implications in inferior petrosal sinus catheterization

OBJECTIVE

The purpose of this study is to describe anatomic variations of the internal jugular vein (IJV), inferior petrosal sinus (IPS) and their confluence pattern and implications in IPS catheterization. The anatomic route of IPS after going out of the cranium and its confluence patterns with IJV and will supply knowledge about typing of IPS-IJV junction.

METHOD

A review of the literature was performed.

RESULTS

There might be different routes for entering the intracranial segment of the IPS and multislice spiral computed tomography (MSCT) is effective in identifying the confluences of the IPS with the IJV and their courses. It is important to find the confluence of IPS with IJV for diagnosis and treatment of intracranial lesions via venous route. Meanwhile, IPS diameter at the confluence can significantly affect success of catheterization.

CONCLUSION

The classification and the theory of the development of the caudal end of the IPS may be useful in establishing treatment strategies that involve endovascular manipulation via the IPS.

Endovascular management of intracranial aneurysms during pregnancy in three cases and review of the literature

We present three cases of cerebral aneurysms (1 unruptured; 2 ruptured) treated with endovascular techniques in pregnancies. The first ruptured case is a 28-year-old female on 20th gestational week. After the endovascular coiling, the patient suffered persistent hemiparesis and delivered a healthy baby by cesarean section. The second ruptured case is a 25-year-old female on 36th week of pregnancy. She died of aneurysm re-rupture after delivery of a healthy baby by cesarean section. The third unruptured case is a 31-year-old woman on the 26th gestational week of pregnancy who died of a giant basilar tip aneurysm after stent-assisted coiling. Ruptured aneurysm obliteration should be prioritized followed by vaginal delivery or cesarean section. The decision regarding the treatment of unruptured aneurysms should be carefully considered on a case-by-case basis. Stent-assisted coiling may be applicable to aneurysm during pregnancy.

China's Medical Education and Interventional Neuroradiology Training

China's medical education system is complex and consists of degree programs lasting from 3 to 8 years, the inconsistency across previous educational backgrounds is a challenge when implementing residency training objectives and contents. Only in several advanced medical universities, education for interventional neuroradiology (INR) is a part of a rotation in the 2-year training for neurosurgery. Advanced INR techniques are confined to big cities such as Beijing, Shanghai and Guangzhou, where most of the Chinese INRs have their 6 to 12 months fellowship to major medical centers. With a tremendous economic growth in the region, we expect that INR practice will evolve at an equally rapid pace, and information presented in this chapter may soon become obsolete.

Onyx Embolization of a Ruptured Rotundum Foreman Artery Aneurysm in a Patient with Moyamoya Disease: A Case Report

BACKGROUND

Hemorrhage caused by the rupture of a rotundum foreman artery pseudoaneurysm in Moyamoya disease (MMD) is rarely reported.

CASE DESCRIPTION

We report a case of 46-year-old man with MMD presenting with left temporal lobe hemorrhage. Cerebral angiogram showed a pseudoaneurysm located on the rotundum branch of the left internal maxillary artery, which anastomosed with a pial vessel. Using onyx 18, we successfully embolized the pseudoaneurysm. The patient was discharged neurologically intact.

CONCLUSION

Given the difficulties and risks of surgery, onyx embolization of rotundum foreman artery aneurysm accompanied with MMD is feasible and effective.

Patient Age, Hemorrhage Patterns, and Outcomes of Arteriovenous Malformation

BACKGROUND

The angioarchitecture and presentation of arteriovenous malformations (AVMs) associated with AVM hemorrhage may vary with patient age. Our aim was to determine the influence of patient age at diagnosis on hemorrhage patterns and outcomes.

METHODS

A consecutive case series of 267 cases of ruptured AVMs was retrospectively analyzed. Hemorrhage patterns (intracerebral hemorrhage, subarachnoid hemorrhage, and intraventricular hemorrhage) were confirmed based on computed tomography imaging at initial diagnosis. Clinical outcomes were classified with a modified Rankin Score. These cases were analyzed with respect to age at diagnosis, hemorrhage patterns, Spetzler-Martin grades, and their clinical outcomes.

RESULTS

During a mean 22.2 months follow-up time (range, 7 hours to 10 years), 212 cases (79.4%) were favorable (modified Rankin Score ≤2) and 55 cases (21.6%) were unfavorable (modified Rankin Score ≥3). The mean age was higher in patients with an unfavorable outcome at follow-up. In univariate analyses, different age groups were significantly associated with bleeding patterns (P = 0.022). Unfavorable outcome was associated with intracerebral hemorrhage (odds ratio, 0.330; 95% confidence interval, 0.142-0.768; P = 0.008) and evacuation of hematoma (odds ratio, 0.195; 95% confidence interval, 0.044-0.867; P = 0.025), whereas intraventricular hemorrhage, subarachnoid hemorrhage, and intraventricular drainage were significantly associated with a favorable outcome. Different age groups were not significantly associated with bleeding patterns, sex, and the location of the AVM, and Spetzler-Martin grades did not show a significant association with the severity of outcomes.

CONCLUSIONS

Different age groups were significantly associated with bleeding patterns. Higher patient age, intracerebral hemorrhage, and evacuation of hematoma seem to be associated with an unfavorable outcome after AVM rupture.

The clinical characteristics and treatment of cerebral AVM in pregnancy

Cerebral arteriovenous malformation (AVM) in pregnancy is a complex situation and there is no agreement on its hemorrhage risk and treatment. Although studies on bleeding risk of cerebral AVMs in pregnancy are very few and there are different results between them, pregnancy will increase the hemorrhagic risk of AVM, and ruptured cerebral AVM in pregnancy should be treated actively. After intracranial hemorrhage, cerebral angiography should be performed for pregnant women shielded correctly. Cerebral angiography could clearly demonstrate the characteristics of cerebral AVM. The results from the literature show that the radiation dose of endovascular and stereotactic radiotherapy for cerebral AVM in pregnancy is below the safety value and is safe. Unruptured AVM in pregnancy, if there is no bleeding factor, such as no coexisting aneurysm, smooth venous drainage, no venous ectasia, or high risk of treatment, should be observed conservatively.

Comparison of Stent-Assisted Coiling vs Coiling Alone in 563 Intracranial Aneurysms: Safety and Efficacy at a High-Volume Center

BACKGROUND

Stent-assisted coiling has been used in both unruptured and ruptured aneurysms, but the safety and efficacy still remain controversial.

OBJECTIVE

To compare the safety and efficacy of stent-assisted coiling with coiling alone for intracranial aneurysms.

METHODS

We retrospectively reviewed 512 patients treated by endovascular coiling or stent-assisted coiling over a 1-year period. The patients' clinical and imaging information was recorded. Procedure-related complication rates, recurrence rates, and clinical outcomes were analyzed in both the total aneurysms and the subgroups of ruptured and unruptured aneurysms.

RESULTS

A total of 243 patients were treated by coiling alone and 269 patients were treated by stent-assisted coiling. Procedure-related complications occurred in 6.2% of patients in the coiling-alone group compared with 6.3% in the stent-assisted coiling group. The procedural permanent morbidity and mortality rates were 1.6% (4/243) and 1.2% (3/243), respectively, in the coiling-alone group and 1.1% (3/269) and 1.5% (4/269), respectively, in the stent-assisted coiling group. A significantly lower recurrence rate was found in the stent-assisted coiling group compared with the coiling-alone group (5.2% vs 16.5%, P = .002). In a comparison of subgroups of ruptured and unruptured aneurysms, the procedural complications rates were comparable in the 2 groups, with a lower recurrence rate in the stent-assisted coiling group. Multivariate analysis showed that larger aneurysm size and higher Hunt and Hess grade were predictors of procedural morbidity; larger aneurysm size, ruptured aneurysm, anterior circulation aneurysms, initial incomplete occlusion, and lack of stent assistance were predictors of recurrence.

CONCLUSION

Compared with coiling alone, stent-assisted coiling may achieve lower recurrence rates, with comparable procedure-related complications and clinical outcomes in both ruptured and unruptured aneurysms.

The clinical characteristics and treatment of cerebral AVM in pregnancy

Cerebral arteriovenous malformation (AVM) in pregnancy is a complex situation and there is no agreement on its hemorrhage risk and treatment. Although studies on bleeding risk of cerebral AVMs in pregnancy are very few, and they provide different results, pregnancy will increase the hemorrhagic risk of AVM and ruptured cerebral AVM in pregnancy should be actively treated. After intracranial hemorrhage, cerebral angiography should be performed for pregnant women shielded correctly. Cerebral angiography could clearly demonstrate the characteristics of cerebral AVM. Results from the literature show that the radiation dose of endovascular and stereotactic radiotherapy for cerebral AVM in pregnancy was below the safety value and was safe. For an unruptured AVM in pregnancy, if there are no bleeding factors, e.g. no coexisting aneurysm, smooth venous drainage, no venous ectasia, or high risk of treatment, then it should be observed conservatively.

Endovascular management of giant aneurysms: An introspection

AIMS

To evaluate the outcome of giant intra-dural aneurysms managed with endovascular techniques.

MATERIALS AND METHODS

We retrospectively reviewed a series of 39 consecutive giant intra-dural aneurysms. The technical feasibility of endovascular treatment, its complications, the angiographic results and the clinical outcome were assessed. Logistic regression analysis was performed to evaluate for predictors of a poor outcome.

RESULTS

Nine patients were left untreated. During a 30 month follow-up, four of them (44.4%) died and two (22.2%) deteriorated. Thirty aneurysms (12 located in the anterior circulation and 18 located in the posterior circulation) were treated using endovascular methods. Of these, 11 were treated by parent vessel occlusion, 11 by stent-assisted coiling, one using only coils, six using solely a stent, and, one using both coils and onyx. During a 28 month follow-up, seven (23.3%) patients died and two (6.7%) patients experienced permanent neurological deficits. The mortality and morbidity in the endovascular group seemed lower than that in the untreated group (P = 0.045, 30% vs. 66.7%). There was no difference in the results of endovascular treatment between giant intra-dural aneurysms located in the posterior and the anterior circulation.

CONCLUSIONS

Giant intra-dural aneurysms, whether treated or not, may have a poor clinical outcome. The outcome following endovascular treatment of these lesions is better than its natural history when left untreated. However, endovascular treatment may often be associated with high complication rates and a low chance of cure.

Targeted embolization reduces hemorrhage complications in partially embolized cerebral AVM combined with gamma knife surgery

This study investigated the effect and safety of targeted embolization in partially embolized cerebral arteriovenous malformation (AVM) followed by gamma knife surgery (GKS). We retrospectively analyzed 86 AVM patients who were targeted embolized by Onyx followed by GKS for residual nidus. Embolization-related complications were collected and the clinical effect was evaluated. During targeted embolization, intranidus or hemodynamic aneurysms and AVM-related fistula were evaluated and targeted embolized. Patients with AVM-related aneurysms and fistula were divided into a targeted embolization group and non-targeted embolization group based on the retrospectively determined treatment strategy. The effect of targeted embolization on hemorrhage risk was evaluated. The overall annual hemorrhage rate was 1.66% with 2.26% for ruptured AVMs and 1.08% for unruptured lesions. The annual mortality rate was 0.4%. Only one in 16 patients with embolization-related complications had permanent neurologic deficit. Twenty-four of 29 cases with intranidus aneurysms were targeted embolized, four of five cases with hemodynamic aneurysms were targeted embolized and eight of nine cases with arteriovenous fistula were targeted embolized. Chi square results showed the hemorrhage complications in the target embolization group were significantly lower than those in the non-target embolization group (p < 0.01). Targeted embolization combined with GKS treatment decreased the annual hemorrhage rate and improved clinical outcome with low permanent complications in partially embolized AVMs. This method could be proposed for the treatment of large brain AVMs when a single-technique treatment is not feasible.

Thromboelastography for monitoring platelet function in unruptured intracranial aneurysm patients undergoing stent placement

This study evaluated patients' preoperative platelet function and the relation between acute embolic or hemorrhagic complications in unruptured intracranial aneurysm patients undergoing stent treatment. From September 2013 to December 2013 we prospectively collected clinical data in all unruptured intracranial aneurysm patients undergoing stent-assisted coiling. All patients received a dual antiplatelet therapy (aspirin and clopidogrel) protocol. Diffusion-weighted 3-T MRI was performed for cerebral aneurysm patients within 24 hours after treatment. Platelet function was tested by thromboelastography. Forty-six patients with 50 intracranial aneurysms treated by stent-assisted coiling were included. Fifty-three stents were deployed in 46 procedures, including 39 Enterprise stents and 14 Solitaire stents. Acute ischemia was detected in the territory of the stented vessel in 25 of 46 patients (54.3%), but did not cause permanent disability. There was a significant difference between groups with and without thromboembolism in terms of percentage platelet inhibition and ADP-induced clot strength (MAADP) for clopidogrel, but no significant difference with aspirin. MAADP had a predictive value yielding an area under the ROC curve of 0.67 (95% CI: 0.57-0.81, P < 0.05). Anterior circulation aneurysms were also associated with ischemic events (P = 0.034). Silent acute embolism may be frequent in unruptured intracranial aneurysm treated with stent-assisted coiling even when dual antiplatelet therapy is given. The antiplatelet inhibition parameter (MAADP) was a predictor for acute thromboembolism in unruptured intracranial aneurysm patients treated by stent-assisted coiling.

Curative glubran 2 embolization of cerebral arteriovenous malformations patient selection and initial results

The liquid embolic agents currently used for embolization of cerebral arteriovenous malformations are Onyx and NBCA. Glubran 2, a cyanoacrylate-based synthetic glue, has recently been applied for embolization of cerebral arteriovenous malformations (AVMs). We report the clinical results of selected cerebral AVMs treated with Glubran 2 targeting for curative embolization. Between October 2011 and March 2013, 31 patients with cerebral AVMs were selected for curative embolization with Glubran 2. There were 19 men and 12 women with a mean age of 32 years (range 4-65 years). Initial clinical presentation included hemorrhage in 28 and seizures in three patients. AVM location was frontal in eight patients, parietal in four, occipital in eight temporal in six, cerebellar in two and cerebellar vermis in three patients. Follow-up was performed clinically and with angiography examination at three to six months. Clinical outcomes were evaluated based on the modified Rankin Scale (mRS). A mean of 2.5 (range, 1-12) feeding pedicles were embolized per patient. Complete angiographic obliteration of AVM was achieved in 27 patients. A hemorrhagic complication was observed in one patient, an ischemic complication in one patient and technical complications in four patients. There was no procedure-related disabling neurological deficit or death at discharge. Additional gamma knife radiosurgery was performed in five patients, including one patient with recurrent AVM. All of the patients had favorable clinical outcomes at three to six month follow-up (mRS≤2). The curative embolization technique with Glubran 2 for selected cerebral AVMs achieved a high initial complete obliteration rate with an acceptable complication frequency.

Risk of rupture and risks of endovascular management of unruptured brain arteriovenous malformations

This study reports the natural history of unruptured brain arteriovenous malformations (AVMs) and the risks involved in their endovascular management. A total of 242 patients at our center were enrolled in the study, which had retrospective and prospective components. We retrospectively assessed the morbidity and mortality related to endovascular management in 125 patients with unruptured AVMs. We prospectively assessed the natural history of unruptured AVMs in 117 patients with newly diagnosed unruptured AVMs; 48 of the patients had no history of seizure (Group 1), whereas 69 had a history of seizure from the lesion (Group 2). The retrospective group was also divided into patients with and without seizures. The cumulative rate of rupture of AVMs in Group 2 was less than 0.8% per year, while the rate was approximately sixfold higher (5.1% per year) in Group 1. The overall cumulative rate of rupture of AVMs was less than 3.0% per year. The overall rate of endovascular management-related morbidity and mortality was 10.6% in Group 2 and 11.9% in Group 1 at 30 days and was 25.9% and 13.6%, respectively, at one year. There was no independent predictor of a poor endovascular outcome. The likelihood of rupture of unruptured AVMs was exceedingly low among patients in Group 2 and was substantially higher among those in Group 1. The risk of morbidity and mortality related to endovascular management greatly exceeded the six-year risk of rupture among patients in Group 2. Endovascular management of an AVM should not be performed to eliminate or to improve seizure frequency.

Innervation of the cerebral dura mater

The trigemino-cardiac reflex during Onyx embolization for dural arteriovenous fistula may be caused by mechanical or chemical stimulus to the terminals of the unencapsulated Ruffini-like receptors stemming from A-axons in the dural connective tissue at sites of dural arteries and sinuses. Slow A (Aδ) and fast A (Aβ) neurons may play a role in the stimulus afferent pathway due to their higher mechanosensitivity and chemosensitivity. These afferent pathway nerves are cholinergic innervations of the dura mater, which also contains vasoactive neuropeptides such as calcitonin gene-related peptide, substance P, and neurokinin A. Stimulation of meningeal sensory fibres can evoke cerebral vasodilation through the peripheral release of neuropeptides, which play a role in headache pathogenesis. These myelinated A-fibers terminate in the deep part (laminae III-V) of the spinal dorsal horn. Its efferent pathway has been defined as the acetylcholinergic vagus nerve. The A11 nucleus, located in the posterior hypothalamus, providing the only known source of descending dopaminergic innervation for the spinal grey matter, can inhibit the neurons in the spinal dorsal horn.

Effect of electromagnetic radiation on the coils used in aneurysm embolization

This study evaluated the effects of electromagnetic radiation in our daily lives on the coils used in aneurysm embolization. Faraday's electromagnetic induction principle was applied to analyze the effects of electromagnetic radiation on the coils used in aneurysm embolization. To induce a current of 0.5mA in less than 5 mm platinum coils required to stimulate peripheral nerves, the minimum magnetic field will be 0.86 μT. To induce a current of 0.5 mA in platinum coils by a hair dryer, the minimum aneurysm radius is 2.5 mm (5 mm aneurysm). To induce a current of 0.5 mA in platinum coils by a computer or TV, the minimum aneurysm radius is 8.6 mm (approximate 17 mm aneurysm). The minimum magnetic field is much larger than the flux densities produced by computer and TV, while the minimum aneurysm radius is much larger than most aneurysm sizes to levels produced by computer and TV. At present, the effects of electromagnetic radiation in our daily lives on intracranial coils do not produce a harmful reaction. Patients with coiled aneurysm are advised to avoid using hair dryers. This theory needs to be proved by further detailed complex investigations. Doctors should give patients additional instructions before the procedure, depending on this study.

Clinical and angiographic outcome of endovascular and conservative treatment for giant cavernous carotid artery aneurysms

This study evaluated the outcome of endovascular and conservative treatment for giant cavernous carotid artery aneurysms (CCAAs). We retrospectively reviewed a series of 35 consecutive giant CCAAs treated with endovascular and conservative treatment. All patients were evaluated by balloon occlusion test (BOT) before treatment. Patients who could tolerate BOT were treated by parent artery occlusion (PAO), those who could not tolerate BOT were treated by stent/coil or conservative methods. Eight patients were treated conservatively, symptoms were worsened in four patients (50%), unchanged in three, and improved in one at 33.6±19.9 months (6~65 months) follow-up. In 27 aneurysms treated with endovascular methods, 17 aneurysms were treated by PAO, eight aneurysms were treated with stent-assisted coil embolization, and two aneurysms were embolized with coils. The initial post-procedure angiogram revealed complete occlusion, neck remnant, and incomplete occlusion in 81.5 %, 11.1 %, and 7.4 %, respectively. Procedure-related mortality and morbidity were 0 and 7.4 %, respectively. At 33.1±17.4 months (4~71 months) follow-up, a good clinical outcome (mRS 0-1) was observed in 25 (92.6%) patients, symptoms were resolved or improved in 20 (74.1%). Statistical analysis showed that risk factors for poor clinical outcome included age of 60 years and older (P=0.006), and conservative treatments (P=0.038). Risk factors for poor clinical outcome of giant CCAAs included conservative treatment and age older than 60 years. A symptomatic giant cavernous carotid aneurysm should be treated. The outcome of endovascular treatment of giant CCAAs is promising.

Prehistoric skull trepanation in China

The term trepanation describes the removal of sections of bone from the cranium. Although others may have made earlier reference to trepanation, in 1995, Chinese archeologists discovered a skull at the Neolithic site Fujia from approximately 3000 bc (the Dawenkou Cultural Period), Guangrao, Dongying, Shandong, China, and after careful examination of the specimen, the archeologists suggested that the procedure had been performed on a living patient who subsequently survived. Archeological evidence supports that the practice of trepanation was widespread.

Arteriovenous malformation in the brain: a theoretical study explaining the behavior of liquid embolic agents during endovascular treatment

There is no theoretical study on blood flow in brain arteriovenous malformation (AVM). We present a numerical theory on AVM and liquid embolic agent AVM embolization. Darcy's law was used to compute flow relations for brain AVMs. Maag's formula was used to explain the diffuse patterns of N-butyl-2-cyanoacrylate (NBCA) and ethylene-vinyl alcohol copolymer (EVOH) in brain AVMs. According to Darcy's law, the instantaneous blood flow rate through an AVM is directly proportional to the pressure drop between two places in the AVM and indirectly proportional to the distance between them. The greater the pressure gradient (through the AVM), the greater the discharge rate, and the discharge rate of blood will often differ through different AVM (or even through the same AVM, in a different direction) even if the same pressure gradient exists in both cases. Subsequent to Darcy's initial discovery, Maag found that the radius of NBCA or EVOH diffusion is inversely proportional to their viscosity. Darcy's Law and Maag's formula could be used to analyze flow patterns of brain AVM and liquid embolic agent behavior in AVM near ideal.