Direct and combined revascularization in pediatric moyamoya disease

Same-day versus staged revascularization of bilateral moyamoya arteriopathy in pediatric patients

PURPOSE

To compare the outcomes of conducting left and right hemisphere surgical revascularization on the same day versus different days for bilateral pediatric moyamoya arteriopathy patients.

METHODS

We retrospectively analyzed mortality, stroke, and transient neurologic event (TNE) rates in North American bilateral pediatric moyamoya arteriopathy patients who underwent bilateral cerebral revascularization.

RESULTS

A total of 38 pediatric (≤ 18 years old) patients at our institution underwent bilateral cerebral revascularization for moyamoya arteriopathy. Of these patients, 24 (63.2%) had both operations on the same day and 14 (36.8%) had the two operations on different days. The average length of stay for patients who underwent same-day bilateral revascularization was 6.9 ± 2.0 days and the average length of stay for each operation for patients who underwent staged bilateral revascularization was 4.5 ± 1.4 days, p = 0.001. While there were 7 (14.6%) postoperative strokes in patients who had both hemispheres revascularized on the same day, 0 (0%) strokes occurred in hemispheres after they had been operated on in the staged cohort, p = 0.042. Additionally, the postoperative stroke-free survival time in the ipsilateral hemisphere and TNE-free survival time were significantly longer in patients in the staged revascularization cohort.

CONCLUSION

Same-day bilateral revascularization was associated with longer length of stay per operation, higher rate of ipsilateral stroke, and shorter postoperative TNE-free and stroke-free survival time in the revascularized hemisphere.

Macrohistory of Moyamoya Disease Analyzed Using Artificial Intelligence

INTRODUCTION

Moyamoya disease is characterized by progressive stenotic changes in the terminal segment of the internal carotid artery and the development of abnormal vascular networks called moyamoya vessels. The objective of this review was to provide a holistic view of the epidemiology, etiology, clinical findings, treatment, and pathogenesis of moyamoya disease. A literature search was performed in PubMed using the term "moyamoya disease," for articles published until 2021.

RESULTS

Artificial intelligence (AI) clustering was used to classify the articles into 5 clusters: (1) pathophysiology (23.5%); (2) clinical background (37.3%); (3) imaging (13.2%); (4) treatment (17.3%); and (5) genetics (8.7%). Many articles in the "clinical background" cluster were published from the 1970s. However, in the "treatment" and "genetics" clusters, the articles were published from the 2010s through 2021. In 2011, it was confirmed that a gene called Ringin protein 213 (RNF213) is a susceptibility gene for moyamoya disease. Since then, tremendous progress in genomic, transcriptomic, and epigenetic profiling (e.g., methylation profiling) has resulted in new concepts for classifying moyamoya disease. Our literature survey revealed that the pathogenesis involves aberrations of multiple signaling pathways through genetic mutations and altered gene expression.

CONCLUSION

We analyzed the content vectors in abstracts using AI, and reviewed the pathophysiology, clinical background, radiological features, treatments, and genetic peculiarity of moyamoya disease.

A meta-analysis of comparisons of various surgical treatments for moyamoya diseases

PURPOSE

Ischemia is one of the most familiar complications in the different procedures for moyamoya disease (MMD), but the optimal surgical approaches for MMD remain unknown. We aimed to evaluate the efficiency of various surgical treatments.

METHODS

A literature search word was performed through four databases such as Cochrane Library, Web of Science, PubMed, and EMBASE for the literature published until May 2021. The I² statistic was used to assess heterogeneity. A random/fixed-effects model was used to pool.

RESULTS

There are a total of 18 studies including three surgical treatments such as including indirect, direct, and combined bypass in this study. The result revealed that indirect bypass was related to a higher incidence of recurrence stroke compared to the direct and combined bypass treatment (p = .001). Furthermore, the cases undergoing direct bypass were associated with a better angiographic change than the indirect bypass (OR = 3.254, p = .013).

CONCLUSION

This meta-analysis demonstrated a positive effect of using the direct and combined bypass to treat MMD compared to indirect bypass due to their lower rates of recurrence stroke.

＜Editors' Choice＞ Indocyanine green emission timing of the recipient artery in revascularization surgery for moyamoya disease

In superficial temporal artery to middle cerebral artery anastomosis with indirect revascularization for patients with moyamoya disease, the optimal method for selecting the most appropriate cortical artery for the recipient in anastomosis has not been established. We investigated the relationship between the fluorescence emission timing of the recipient artery in the preanastomosis indocyanine green videoangiography and operative outcomes. This retrospective study included 51 surgical revascularization procedures for 39 moyamoya disease patients. The enrolled surgical procedures were classified into three groups based on the fluorescence emission timing of the recipient artery in preanastomosis indocyanine green videoangiography: the EARLIEST, the INTERMEDIATE, and the LATEST. Clinical characteristics and operative outcomes were also collected. The occurrence of white thrombus at the anastomosis site and symptomatic hyperperfusion showed significant differences between the groups classified by the fluorescence emission timing of the recipient artery in preanastomosis indocyanine green videoangiography (white thrombus, p = 0.001; symptomatic hyperperfusion, p = 0.026). The development of white thrombi was significantly higher in the LATEST group, and all symptomatic hyperperfusion was observed in the EARLIEST group. These results indicated that the LATEST group had a significantly higher risk for developing white thrombus, and the EARLIEST group was prone to occur symptomatic hyperperfusion. Selecting the recipient artery based on evaluating the fluorescence emission timing in preanastomosis indocyanine green videoangiography may be useful in reducing perioperative complications.

Effects of aspirin and heparin treatment on perioperative outcomes in patients with Moyamoya disease

BACKGROUND

When superficial temporal artery-middle cerebral artery bypass is combined with indirect methods (e.g., revascularization surgery) to treat Moyamoya disease (MMD), antiplatelet treatment can impact bypass patency, infarction, or hemorrhage complications. Recently, heparin has been proposed as an anticoagulant treatment against white thrombus at the anastomosis site. The study aims to evaluate the effect of aspirin on the perioperative outcomes and investigate the results of heparin treatment for white thrombus.

METHODS

This retrospective study included 74 procedures of combined revascularization surgery for MMD patients who either received or did not receive aspirin. Perioperative outcomes were compared between the two groups. In addition, the effects of heparin treatment for white thrombus were evaluated.

RESULTS

The rate of white thrombus at the anastomosis site was significantly higher in the non-aspirin medication group (univariate: p = 0.032, multivariate: p = 0.044) and, accordingly, initial bypass patency was lower in the non-aspirin medication group (p = 0.049). Of the 17 patients with white thrombus development, five received heparin injections, and all white thrombi disappeared; however, there was one case of epidural hematoma and another of subdural hematoma. The risk of hemorrhagic complications was significantly higher in the surgical procedures that received heparin injections (p = 0.021).

CONCLUSIONS

In MMD patients who received combined revascularization surgery, aspirin medication lowered the occurrence of white thrombus. Heparin injections help to treat white thrombus but can enhance the risk of hemorrhagic complications.

Anatomic Variation of the Superficial Temporal Artery and Posterior Auricular Artery in a Pediatric Moyamoya Disease Population

BACKGROUND AND PURPOSE

In certain cases of pediatric patients with Moyamoya disease undergoing encephaloduroarteriosynangiosis (EDAS) treatment, the posterior auricular artery can be used as an alternative when the parietal branch of the superficial temporal artery is unavailable. In this study, anatomic variations of the superficial temporal and posterior auricular arteries in pediatric patients with Moyamoya disease and postoperative outcomes of posterior auricular artery-EDAS are explored.

MATERIALS AND METHODS

Medical records of 572 patients with Moyamoya disease who underwent surgical procedures from 2007 to 2017 at the Seoul National University Children's Hospital were reviewed. Anatomic classifications of the superficial temporal and posterior auricular arteries were based on previous classifications. Postoperative hemodynamic changes of posterior auricular artery-EDAS were analyzed using the Matsushima grade. Also, Karnofsky Performance Scale and mRS scores of posterior auricular artery-EDAS cases were reviewed to identify postoperative clinical outcomes.

RESULTS

Among 1144 hemispheres, 24 were considered posterior auricular artery-EDAS candidates (2.1%). Of those, 10 hemispheres underwent posterior auricular artery-EDAS (41.7%, in total hemispheres 0.9%). Comparing the Matsushima grades of the superficial temporal artery-EDAS and posterior auricular artery-EDAS groups showed similar postoperative revascularization. Postoperative Karnofsky Performance Scale and mRS scores of patients having undergone posterior auricular artery-EDAS did not show deterioration.

CONCLUSIONS

In approximately 2% of pediatric patients with Moyamoya disease for whom the superficial temporal artery is unavailable as the EDAS donor, the posterior auricular artery can be considered an alternative. On the basis of the results, the clinical outcome of posterior auricular artery-EDAS was not inferior to that of superficial temporal artery-EDAS. Hence, we suggest an in-depth consideration of the posterior auricular artery as the donor artery if the superficial temporal artery parietal branch is unavailable.

Limits and pitfalls of indirect revascularization in moyamoya disease and syndrome

Moyamoya vasculopathy is a rare chronic cerebrovascular disorder characterized by the stenosis of the terminal branches of the internal carotid arteries and the proximal tracts of anterior and middle cerebral arteries. Although surgical revascularization does not significantly change the underlying pathogenic mechanisms, it plays a pivotal role in the management of affected individuals, allowing to decrease the risk of ischemic and hemorrhagic complications. Surgical approaches may be direct (extracranial-intracranial bypass), indirect, or a combination of the two. Several indirect techniques classifiable according to the tissue (muscle, periosteum, galea, dura mater, and extracranial tissues) or vessel (artery) used as a source of blood supply are currently available. In this study, we reviewed the pertinent literature and analyzed the advantages, disadvantages, and pitfalls of the most relevant indirect revascularization techniques. We discussed the technical aspects and the therapeutical implications of each procedure, providing a current state-of-the-art overview on the limits and pitfalls of indirect revascularization in the treatment of moyamoya vasculopathy.

Peek through the smoke: a report of moyamoya disease in a 32-year-old female patient presenting with ischaemic stroke

Moyamoya disease is a vasculopathy causing chronic progressive stenosis and occlusion of the large arteries of the circle of Willis that could lead to brain ischaemia. The condition may also present with haemorrhagic strokes. This is a case report of moyamoya disease in a 32-year-old woman presenting with ischaemic stroke. The report describes her inpatient stay and investigations and findings.The report reviews the main aspects of moyamoya disease definition, epidemiology, clinical features, diagnosis, classification and treatment. This case is interesting because her first presentation occurred after 3 months of her second delivery. Whether the different physiological stresses of pregnancy, child birth and puerperium have had some effect in accelerating the pathogenesis of her moyamoya disease remains unknown. ¹.

Carotid Endarterectomy in Moyamoya Disease: A Case Report

We report the case of a 55-year-old female who presented with symptomatic high-grade stenosis of the right internal carotid artery, years after her diagnosis of moyamoya disease (MMD), which had been treated with extensive carotid and cerebral vascular reconstructions. A percutaneous carotid revascularization was unsuccessful, and a carotid endarterectomy with bovine patch angioplasty was subsequently performed. The presence of symptomatic atherosclerotic carotid disease in combination with MMD, with all the perioperative challenges, has not been previously described.

Radial Artery Bypass for Intractable Vertebrobasilar Insufficiency: Case Series and Review of the Literature

BACKGROUND

Vertebrobasilar insufficiency resulting from embolism, atherosclerosis, or arterial dissection has long been a challenge for successful management and outcomes. The main treatment options include medical therapy, angioplasty and stenting, and surgical revascularization. Unlike cardiac or peripheral vascular revascularization, large randomized trials with cerebrorevascularization have not revealed favorable outcomes. In patients who have failed maximal medical therapy, and having persistent debilitating symptomology, cerebral revascularization may still be a viable option.

METHODS

We report 3 patients who presented with symptoms of vertebrobasilar ischemia. The diagnosis was verified by computerized tomographic arteriography and digital subtraction angiography.

RESULTS

These patients subsequently underwent revascularization with a radial artery graft. We also present a comprehensive review of the literature of treatment for vertebrobasilar insufficiency.

CONCLUSIONS

Surgical revascularization should be considered in the posterior circulation in the rare subset of patients with VBI, who remain symptomatic despite having a protracted course of maximal medical therapy with large- and medium-sized vessel occlusions and poor collateral circulation.

Down syndrome and moyamoya: clinical presentation and surgical management

OBJECT Moyamoya can cause cerebral ischemia and stroke in Down syndrome (DS) patients. In this study, the authors defined a surgically treated population of patients with DS and moyamoya and compared their clinical presentation, response to surgical treatment, and long-term prognosis with those of the general population of patients with moyamoya but without DS. METHODS This study was a retrospective review of a consecutive operative series of moyamoya patients with DS treated at Boston Children's Hospital from 1985 through 2012. RESULTS Thirty-two patients, average age 9.7 years (range 1.8-29.3 years), underwent surgery for moyamoya in association with DS. The majority presented with ischemic symptoms (87% stroke, 42% transient ischemic attacks). Twenty-four patients (75%) had congenital heart disease. Nineteen patients (59%) had bilateral moyamoya on presentation, and 13 presented with unilateral disease, of which 2 progressed to surgery on the opposite side at a later date. Patients were followed for a median of 7.5 years (1-20.2 years) after surgery, with no patients lost to follow-up. Follow-up arteriography demonstrated Matsushima Grade A collaterals in 29 of 39 (74%) hemispheres, Grade B in 5 (13%), and Grade C in 5 (13%). Complications included postoperative strokes in 2 patients, which occurred within 48 hours of surgery in both; one of these patients had arm weakness and the other confusion (both had recovered completely at follow-up). Seizures occurred in 5 patients perioperatively, including one who had a new seizure disorder related to hypocalcemia. CONCLUSIONS Moyamoya disease is a cause of stroke in patients with DS. Both the incidence of preoperative stroke (87% vs 67%) and the average age at diagnosis for children under age 21 (8.4 vs 6.5 years) were greater in patients with DS and moyamoya than in the general moyamoya surgical population, suggesting a possible delay in reaching a correct diagnosis of the cause of cerebral ischemia in the DS patient population. Pial synangiosis provided long-term protection from stroke in all patients treated.

Clinical Features, Surgical Treatment, and Long-Term Outcome in Pediatric Patients with Moyamoya Disease in China

Background: There was few detailed demographic and clinical data about Chinese patients with moyamoya disease. Here we describe the clinical features, surgical treatment, and long-term outcome of pediatric patients with moyamoya disease at a single institution in China. Methods: Our cohort included 288 pediatric patients with moyamoya disease. The demographic and clinical characteristics were obtained by retrospective chart review and long-term outcome was evaluated using the stroke status. Univariate and multivariate logistic regression analyses were performed to determine the risk factors for clinical outcome. The risk of subsequent stroke was determined using the Kaplan-Meier method. Results: The median age for the onset of symptoms was 8.0 years. The ratio of female to male patients was 1:1. Familial occurrence of moyamoya disease was 9.4%. The incidence of postoperative complications was 4.2%. Postoperative ischemic events were identified as predictors of unfavorable clinical outcome, while older age of symptom onset was associated with a favorable clinical outcome. The Kaplan-Meier estimate stroke risk was 5% in the first 2 years, and the 5-year-Kaplan-Meier risk of stroke was 9% after surgery for all patients treated with surgical revascularization. Overall, 86% of patients had an independent life with no significant disability. Conclusion: This long-term survey demonstrated that most surgically treated pediatric patients with MMD maintain good outcomes. Our results indicate that an early diagnosis and active intervention before the establishment of irreversible hemodynamic change are essential to achieve a favorable clinical outcome.

Case Report: A case report of Moyamoya disease in a 36 year old African American woman

Moyamoya is a rare idiopathic progressive vaso-occlusive disease characterized by irreversible condition of main blood vessels to the brain as they enter into the skull. We present a case of 36 year old African American female presenting to the Out Patient Clinic with headache which were on and off for 4-6 months and did not relieve on routine medical therapy. It was associated with weakness on right side for last few days. The patient was investigated with CT Angiogram, diagnosed as Moyamoya disease and operated. She has been followed up for the last 5 years and the patient has not complained of any headaches or focal neurological symptoms.

Pial synangiosis in patients with moyamoya younger than 2 years of age

Object Patients with moyamoya who are younger than 2 years of age represent a therapeutic challenge because of their frequent neurological instability and concomitant anesthetic risks. The authors report their experience with pial synangiosis revascularization in this population. Methods The authors reviewed the clinical and radiographic records of all patients with moyamoya in a consecutive series of patients under 2 years of age, who underwent cerebral revascularization surgery using pial synangiosis at a single institution. Results During a 12-year period (1994-2005), 34 procedures (bilateral in 15 patients, unilateral in 4) were performed in 19 patients younger than 2 years (out of a total of 456 procedures in 240 patients). Eighteen of these patients presented with either stroke or transient ischemic attack. The average age of the 19 patients at first surgery was 1.4 years (range 6 months-1.9 years). Unanticipated staged operations occurred in 3 patients, due to persistent electroencephalographic changes during the initial surgery in 2 cases and due to brain swelling during the procedure requiring ventriculostomy in the other. There were 2 perioperative strokes; both patients had postoperative seizures but made clinical recoveries. The average follow-up was 7 years (range 1-14 years). Long term, at follow-up, 13 patients (68%) were clinically independent for their age, with 8 (42%) having no significant deficit. Late complications included subdural hygroma evacuation (1), additional revascularization procedures performed years later for frontal lobe ischemia (2), late infarction (1), and asymptomatic ischemic change on routine follow-up MRI studies (1). All patients who had both pre- and postoperative angiography demonstrated progression of disease. Conclusions Despite the challenges inherent to this population, the majority of children with moyamoya under the age of 2 years have a good long-term prognosis. The data from this study support the use of pial synangiosis as a safe, effective, and durable method for treatment of moyamoya for most children in this potentially high-risk population.

Thirteen-year Experience of 44 Patients with Adult Hemorrhagic Moyamoya Disease from a Single Institution: Clinical Analysis by Management Modality

Our objective was a retrospective assessment of the management modalities that provided the most beneficial treatment in hemorrhagic moyamoya disease during the last 13 years at our institution. The clinical results of 44 patients with hemorrhagic moyamoya disease were investigated, comparing revascularization surgery (direct, indirect, and combined bypass) or conservative treatment. Angiographic features, rebleeding, and clinical outcome were investigated. Six of the 35 patients (17.1%) with revascularization surgery experienced rebleeding, as did 4 of 9 patients (44.4%) with conservative treatment. However, patients who underwent bypass surgery had a lower chance of rebleeding. No significant difference in chance of rebleeding was observed between bypass surgery and non surgery groups (p > 0.05). Cerebral angiography performed after bypass surgery showed that for achieving good postoperative revascularization, direct and combined bypass methods were much more effective (p < 0.05). While the risk of rebleeding in the revascularization group was generally lower than in the conservative treatment group, there was no statistically significant difference between treatment modalities and conservative treatment. Although statistical significance was not attained, direct and combined bypass may reduce the risk of hemorrhage more effectively than indirect bypass.

Pediatric Moyamoya disease

Background:

Moyamoya disease (MMD) is a progressive cerebrovascular occlusive disease of the bilateral internal carotid arteries that leads to a compensatory abnormal vascular network at the base of the brain. Its average annual incidence 0.54 per 100,000 population but it is the most common pediatric cerebrovascular disease in East Asia. The reported incidence in USA is approximately 0.086 per 100,000 patients.

Case Report:

We present a case of Moyamoya disease that was to detected in a 7-year-old female who presented with transient altered mental status.

Conclusions:

Moyamoya disease can be diagnosed if history, physical exam and brain imaging is highly suspicious. Conventional angiography remains the gold standard for diagnosis and aids in surgical planning for patients with suspected Moyamoya disease.

Angiographic results of indirect and combined bypass surgery for adult moyamoya disease

OBJECTIVE

The aim of this study was to compare the efficacy of indirect and combined bypass surgery for treatment of adult moyamoya disease (MMD). The definition of combined bypass surgery is a combination of superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis and indirect anastomosis. Development of collateral circulation after surgery was investigated.

METHODS

Forty three patients (58 hemispheres) with MMD were followed by cerebral angiography for at least six months after surgery, between May 2002 and July 2011. Indirect and combined revascularization surgeries were performed in 33 and 25 cases, respectively. Good outcome was defined as more than group B, in accordance with the method suggested by Matsushima.

RESULTS

Development of collateral circulation was not affected by sex (p = 0.493), clinical features (p = 0.206), or Suzuki stage (p = 0.428). Based on postoperative cerebral angiography, the combined bypass surgery group showed a better angiographic outcome, than the encephaloduroarteriomyosynangiosis (EDAMS) group (p = 0.100, odds ratio [OR] 4.107, 95% confidence interval [CI] 0.700 - 24.096). The combined bypass group showed a better response than the encephaloduroarteriogaleosynangiosis (EDAGS) group (p = 0.088, OR 4.600, 95% CI 0.721 - 29.332). Similar responses were observed for EDAGS and EDAMS (p = 0.886, OR 1.120, 95% CI 0.239 - 5.251). The combined bypass group showed a better response than the indirect group (p = 0.064, OR 4.313, 95% CI 0.840 - 22.130).

CONCLUSION

Results of this study demonstrate that combined bypass results in better revascularization on angiographic evaluation in adult MMD. Therefore, among surgical procedures, combined bypass is a choice that can be recommended.

Discovery of asymptomatic moyamoya arteriopathy in pediatric syndromic populations: radiographic and clinical progression

OBJECT

Limited data exist to guide management of incidentally discovered pediatric moyamoya. Best exemplified in the setting of unilateral moyamoya, in which the unaffected side is monitored, this phenomenon also occurs in populations undergoing routine surveillance of the cerebral vasculature for other conditions, such as sickle cell disease (SCD) or neurofibromatosis Type 1 (NF1). The authors present their experience with specific syndromic moyamoya populations to better characterize the natural history of radiographic and clinical progression in patients with asymptomatic moyamoya.

METHODS

The authors performed a retrospective review of the clinical database of the neurosurgery department at Children's Hospital Boston, including both nonoperative referrals and a consecutive series of 418 patients who underwent surgical revascularization for moyamoya disease between 1988 and 2010.

RESULTS

Within the period of time studied, 83 patients were asymptomatic at the time of radiographic diagnosis of moyamoya, while also having either unilateral moyamoya or moyamoya in association with either SCD or NF1. The mean age at presentation was 9.1 years (range 1-21 years), and there were 49 female (59%) and 34 male (41%) patients. The mean follow-up duration was 5.4 ± 3.8 years (mean ± SD), with 45 patients (54%) demonstrating radiographic progression and 37 (45%) becoming symptomatic within this period. Patients with SCD had the highest incidence of both radiographic (15 patients [75%]) and clinical (13 patients [65%]) progression, followed by NF1 (20 patients [59%] with radiographic progression and 15 patients [44%] with clinical progression) and patients with unilateral moyamoya (10 patients [35%] with radiographic progression and 9 patients [31%] with clinical progression).

CONCLUSIONS

Radiographic progression occurred in the majority of asymptomatic patients and generally heralded subsequent clinical symptoms. These data demonstrate that moyamoya is a progressive disorder, even in asymptomatic populations, and support the rationale of early surgical intervention to minimize morbidity from stroke.

Clinical features, prothrombotic risk factors, and long-term follow-up of eight pediatric Moyamoya patients

Background and Purpose

The aim of this study was to elucidate the clinical features, prothrombotic risk factors, and outcome of pediatric Moyamoya patients.

Methods

Patients diagnosed with Moyamoya disease at a tertiary center between January 2000 and December 2006 were enrolled in this study. The clinical presentations, underlying diseases, prothrombotic risk factors, family history of thrombosis, radiological findings, treatment, and outcome of the patients were reviewed retrospectively.

Results

Eight patients with angiographically proven Moyamoya disease were identified, one of whom had neurofibromatosis type I and one had Down syndrome. The age at diagnosis varied between 19 months and 11 years (73.4±41.8 months, mean±SD). The follow-up period after diagnosis was 52.5±14.8 months. In six patients, the initial clinical presentation was hemiparesis. None of the patients had any identifiable prothrombotic factors. Despite medical and surgical treatment, three patients had recurrences and one died. Only two patients recovered without sequelae.

Conclusions

The value of prothrombotic risk factor evaluation appears to be limited in Moyamoya patients; the outcome for pediatric patients remains dismal.

Long-term follow-up results in 142 adult patients with moyamoya disease according to management modality

BACKGROUND

To clarify the most beneficial treatment of the management modality based on our experience with adult moyamoya disease (MMD).

METHODS

From 1998 to 2010, clinical results of 142 patients (ischemic, 98; hemorrhagic, 44) with adult MMD were investigated according to management modality. Revascularization surgery (direct, indirect, and combined bypass) was performed in 124 patients. We observed the clinical course of 18 patients who were treated conservatively. Clinical outcome, angiographic features, hemodynamic change, and incidence of recurrent stroke were investigated pre- and postoperatively.

RESULTS

In patients with ischemic MMD, direct and combined bypasses were more effective treatments to prevent recurrent ischemic stroke than indirect bypass surgery (P < 0.05). In patients with hemorrhagic MMD, rebleeding was less likely to occur in patients who had undergone bypass surgery. However, no significant difference was observed in the rebleeding rate between patients with and without revascularization surgery (P > 0.05). An angiogram after bypass surgery comparing the extent of revascularization and reduction of moyamoya vessels in patients treated with direct, indirect, and combined bypass showed a significant difference (P < 0.05) in favor of direct and combined bypass. Postoperative angiographic changes and SPECT results demonstrated significant statistical correlation (P < 0.05).

CONCLUSION

Revascularization surgery was effective in further ischemic stroke prevention to a statistically significant extent. Direct and combined bypasses were more effective to prevent recurrent ischemic stroke than indirect bypass. However, there is still no clear evidence that revascularization surgery significantly prevents rebleeding in adult MMD patients. More significant angiographic changes were observed in direct and combined bypasses compared with indirect bypass.

Moyamoya disease: functional and neurocognitive outcomes in the pediatric and adult populations

OBJECT

Moyamoya disease is an occlusive cerebrovascular disorder commonly resulting in neurocognitive impairment. The cognitive outcome parameters commonly affected are intelligence, memory, executive function, and quality of life. In this paper, the authors review the existing literature on cognitive and clinical outcomes in adult and pediatric moyamoya populations separately.

METHODS

A systematic review of the cognitive and clinical outcome literature was performed using the PubMed/MEDLINE database. Outcomes data were contrasted between adult and pediatric populations.

RESULTS

Intelligence is the main cognitive outcome parameter affected in pediatric patients with moyamoya disease, whereas adults most commonly suffer from executive function impairment. Memory has not been studied sufficiently in pediatric patients, and its dysfunction in the adult population remains controversial. Quality of life has not been studied appropriately in either population. Surgical revascularization is the only beneficial treatment option, and a combination of direct and indirect bypass techniques has shown benefit, but the impact on the above-mentioned parameters has not been sufficiently elucidated.

CONCLUSIONS

Moyamoya disease affects the cognition and daily function in pediatric patients to a greater extent than in adult patients. Due to the rarity of the disease, there is a distinct lack of high-level evidence regarding cognitive and clinical outcomes.

Effect of mouth opening on bypass function after combined revascularization for Moyamoya disease

Moyamoya disease represents a rare steno-occlusive disease of the internal carotid artery (ICA) with a reactive and pathological basal network of collateral vessels. It may lead to ischemic stroke or intracerebral hemorrhage. Treatment options are either direct or indirect revascularization procedures or a combination thereof. Specialized centers report sufficient revascularization in most patients and low complication rates.Between 2005 and 2008, direct extra-intracranial bypass surgery in combination with encephalomyosynangiosis (EMS) was performed in 71 Moyamoya patients at the Mannheim University Medical Center.Following one case of reversible neurological deficits associated with mouth opening, we prospectively evaluated the effect of mouth opening on bypass function in this patient and four further consecutive patients by digital subtraction angiography.Three out of five patients showed alterations in bypass patency upon mouth opening. The obstruction was located at the junction of the bypass and the temporal muscle. Two temporary occlusions and one case of decreased flow were observed. One patient demonstrated reversible hemiparesis and aphasia.

Outcome of repeat revascularization surgery for moyamoya disease after an unsuccessful indirect revascularization

Object

Revascularization for moyamoya disease, either by direct anastomosis or indirect procedures, is an accepted and effective form of treatment for prevention of future ischemic events. Indirect procedures do not provide sufficient collateral vessels in a subset of patients, who then have persistent or new symptoms. Repeat revascularization procedures may be recommended for these patients.

Methods

Sixteen patients underwent repeat revascularization after undergoing an indirect procedure in the same hemisphere. These patients were included in the study, and a retrospective review of their clinical details, neuroimaging results, surgical details, and outcome was performed. Direct revascularization was the procedure of choice; however, in patients with no acceptable recipient vessel (> 0.6 mm) the authors added a second indirect procedure for further revascularization.

Results

Over the last 19 years, 16 patients (8 male and 8 female patients, age range 5–48 years, mean 16.7 years, 10 pediatric and 6 adult patients) underwent repeat revascularization for moyamoya disease. Initially all patients presented with ischemic symptoms (4 transient ischemic attacks [TIAs] and 12 strokes; 2 patients had bilateral symptoms). Angiography revealed that 13 patients had bilateral disease, and 3 had unilateral disease. Initial surgery was bilateral encephaloduroarteriosynangiosis (EDAS) in 9, unilateral EDAS alone in 3, unilateral EDAS with contralateral superficial temporal artery–middle cerebral artery (STA-MCA) bypass in 2, bilateral encephalomyosynangiosis (EMS) in 1, and unilateral EMS in 1. Thirteen of the 16 patients continued to have TIAs in the hemisphere ipsilateral to surgery, whereas 1 patient had seizures and cognitive deficit, 1 had asymptomatic infarct on MR imaging, and 1 had visual symptoms. Poor revascularization was seen on angiography studies in all patients. The median duration between the surgeries was 24 months (3 months–10 years).

Repeat revascularization was performed in 23 hemispheres (16 patients). Direct revascularization was performed in 14 hemispheres (60.9%): STA-MCA bypass in 10, external carotid artery–MCA vein bypass in 2, occipital artery (OA)–MCA in 1, and OA–posterior cerebral artery in 1 hemisphere. Indirect revascularization was performed for patients without an acceptable recipient vessel, and was done in 9 hemispheres. The procedures included EMS (4 hemispheres), repeat EDAS (2), and omental transposition (3). There was 1 postoperative death in a patient undergoing a high-flow vein graft implantation. None of the other patients experienced any neurological worsening after surgery.

Follow-up was available in all patients, ranging from 3 to 144 months (mean 34 months, median 12 months). Of the 15 patients who survived repeat revascularization surgery, 12 (80%) were free from any TIA, stroke, or any other neurological symptoms. Two patients had occasional TIAs, less frequent than before, whereas 1 patient had frequent TIAs and underwent revision of the revascularization. Angiographic studies were available in 11 patients, and showed improved flow in the hemispheres in 10 patients. Follow-up MR imaging performed at 6 months did not reveal a new infarct in any patient.

Conclusions

Repeat revascularization procedures are effective for patients who are clinically symptomatic and have inadequate collateral vessels following indirect procedures. Although direct procedures are preferred, the choice of procedure depends on the operative findings and the status of donor and recipient vessels.

Transzygomatic-Subtemporal Approach for Middle Meningeal-to-P2 Segment of the Posterior Cerebral Artery Bypass: An Anatomical and Technical Study

We evaluated the use of a bypass between the middle meningeal artery (MMA) and P2 segment of the posterior cerebral artery (PCA) as an alternative to an external carotid artery (ECA-to-PCA) anastomosis. Five adult cadaveric heads (10 sides) were used. After a temporal craniotomy and zygomatic arch osteotomy were performed, the dura of the floor of the middle cranial fossa was separated and elevated. The MMA was dissected away from the dura until the foramen spinosum was reached. Intradurally, the carotid and sylvian cisterns were opened. After the temporal lobe was retracted, the interpeduncular and ambient cisterns were opened and the P2 segment of the PCA was exposed. The MMA trunk was transsected just before the bifurcation of its anterior and posterior branches where it passes inside the dura and over the foramen spinosum. It was anastomosed end to side with the P2 segment of the PCA. The mean caliber of the MMA trunk before its bifurcation was 2.1 +/- 0.25 mm, and the mean caliber of the P2 was 2.2 +/- 0.2 mm. The mean length of the MMA used to perform the bypass was 32 +/- 4.1 mm, and the mean length of the MMA trunk was 39.5 +/- 4.4 mm. This bypass procedure is simpler to perform than an ECA-to-P2 revascularization using long grafts. The caliber and length of the MMA trunk are suitable to provide sufficient blood flow. Furthermore, the course of the bypass is straight.

Childhood moyamoya disease and moyamoya syndrome: a pictorial review

Moyamoya disease is an uncommon chronic cerebrovasculopathy, characterized by progressive stenosis of the terminal portion of the internal carotid artery and its main branches, in association with the development of compensatory collateral vessels at the base of the brain. The etiology is unknown, and was originally considered exclusive to East Asia, with particular prevalence in Japan. Moyamoya disease is increasingly diagnosed throughout the world, and represents an important cause of childhood stroke in Western countries. In some cases, similar angiographic features are evident in children with other medical conditions, such as sickle cell disease and Down syndrome. In these instances, the term "moyamoya syndrome" is used. Diagnosing the vasculopathy, excluding possible associated conditions, and planning treatment and follow-up imaging comprise important aspects of clinical management. We review the key imaging features of childhood moyamoya disease and syndrome, present examples of its associations, and discuss new neuroradiologic methods that may be useful in management.

Indirect revascularization techniques for treating moyamoya disease

There have been many indirect revascularization techniques described by surgeons for the treatment of moyamoya disease. These surgical procedures are typically used more commonly in pediatric, than in adults', cases. Some of the techniques include: cervical sympathectomy, omental transplantation, multiple burr holes, encephalo-myo-synangiosis (EMS), encephalo-arterio-synangiosis (EAS), encephalo-duro-synangiosis (EDS), encephalo-myo-arterio-synangiosis (EMAS), encephalo-duro-arterio-synangiosis (EDAS), encephalo-duro-arterio-myo-synangiosis (EDAMS), encephalo-duro-galeo (periosteal)-synangiosis (EDGS), and combinations of all the above. This chapter will detail the technical aspects of many of these procedures and some of the reported clinical outcomes.

Cerebral angiopathies as a cause of ischemic stroke in children: differential diagnosis and treatment options

BACKGROUND

Ischemic stroke in children can present with an epileptic seizure or be initially asymptomatic. The median time to diagnosis is 24 hours.

METHODS

This review is based on a selective literature search, with additional consideration of published guidelines and the authors' personal experience.

RESULTS

In Europe and the USA, the combined incidence of ischemic and hemorrhagic stroke in childhood is 2.5 to 10 per 100 000 children per year. 40% of ischemic strokes in childhood occur after an infectious illness or in association with a congenital heart defect, sickle-cell anemia, or a coagulopathy. Arterial dissection and chronic, progressive cerebral arteriopathies, particularly moyamoya disease, each account for up to 10% of childhood strokes. Magnetic resonance imaging can be used to demonstrate infarcts and to display the perfusion of ischemic areas and the surrounding brain tissue; arterial and venous occlusions can be defined more precisely. Children with arterial dissection, vasculitis, and para-infectious cerebral ischemia should be treated empirically, with medications and supportive care, according to the treatment plans developed for adults. For patients with moyamoya disease, surgical revascularization with extra-intracranial bypass techniques is recommended.

DISCUSSION

The current data provide an inadequate evidence base for the treatment of stroke in children. Potential revascularization or thrombolysis must be discussed individually in each case. For the treatment of temporary, para-infectious cerebral ischemia, hemodynamic optimization is an available option. Better evidence is needed regarding the surgical treatment of moyamoya disease.

Patients with moyamoya disease presenting with movement disorder

Moyamoya disease is a rare cerebrovascular disease characterized by idiopathic bilateral stenosis or occlusion of bilateral internal carotid arteries and the development of characteristic leptomeningeal collateral vessels at the base of the brain. Typical presentations include transient ischemic attacks or stroke, and hemorrhage. Presentation with movement disorders is extremely rare, especially in the pediatric population. The authors describe the cases of 4 children with moyamoya disease who presented with movement disorders. Among 446 patients (118 pediatric) with moyamoya disease surgically treated by the senior author, 4 pediatric patients had presented with movement disorders. The clinical records, imaging studies, surgical details, and postoperative clinical and imaging data were retrospectively reviewed. The initial presenting symptom was movement disorder in all 4 patients: chorea in 2, hemiballismus in 1, and involuntary limb shaking in 1. All the patients had watershed infarcts involving the frontal subcortical region on MR imaging. Additionally, 1 patient had a ganglionic infarct. Single-photon emission computed tomography studies showed frontoparietal cortical and subcortical hypoperfusion in all patients. Three patients had bilateral disease, whereas 1 had unilateral disease. All the patients underwent superficial temporal artery-middle cerebral artery bypass. Postoperatively, all 4 patients had complete improvement in their symptoms. The SPECT scans revealed normal perfusion in 3 patients and a small residual perfusion deficit in 1. Movement disorders are a rare presenting feature of moyamoya disease. Hypoperfusion of the frontal cortical and subcortical region was seen in all patients, and the symptomatology was attributed to ischemic dysfunction and imbalance in the cortical-subcortical-ganglionic-thalamic-cortical circuitry. Combined revascularization with superficial temporal artery-middle cerebral artery bypass and encephaloduroarteriosynangiosis leads to excellent results.

Moyamoya disease in children

PURPOSE

Moyamoya disease, a rare cause of pediatric stroke, is a cerebrovascular occlusive disorder resulting from progressive stenosis of the distal intracranial carotid arteries and their proximal branches. In response to brain ischemia, there is the development of basal collateral vessels, which give rise to the characteristic angiographic appearance of moyamoya. If left untreated, the disease can result in overwhelming permanent neurological and cognitive deficits.

METHODS

Whereas moyamoya disease refers to the idiopathic form, moyamoya syndrome refers to the condition in which children with moyamoya also have a recognized clinical disorder. As opposed to adults who typically present in the setting of intracranial hemorrhage, the classic pediatric presentation is recurrent transient ischemic attacks and/or completed ischemic strokes.

RESULTS

Surgical revascularization, including direct and indirect techniques, remains the mainstay of treatment, and has been shown to improve long-term outcome in children with moyamoya.

CONCLUSION

The authors discuss the diagnosis and treatment of moyamoya disease in the pediatric population.

Prevention of secondary ischemic events by superficial temporal artery-middle cerebral artery bypass surgery after tuberculosis-induced vasculopathy in a 5-year-old child

Tuberculosis-related vasculopathy and resulting ischemic events are a common finding after tuberculous meningitis (TBM) in children. The authors report on a case of recurring ischemic episodes that were refractory to repetitive endovascular procedures (transluminal angioplasty, stent insertion, in-stent vessel dilation). After failure of endovascular treatment, extracranial-intracranial (EC-IC) bypass surgery was performed to prevent further ischemia. This 5-year-old girl presented with a series of ischemic events in the left middle cerebral artery (MCA) territory 12 months after her presentation with TBM. Angiography studies showed a 50% lumen reduction of the left MCA. After failure of antithrombocyte aggregation and repeated endovascular procedures to prevent new ischemia, EC-IC bypass surgery was performed. The left superficial temporal artery-MCA bypass was found to be capable of preventing new ischemic events in the 21-month follow-up period, despite a near-total MCA occlusion on follow-up conventional and MR angiography studies. Bypass surgery seems to be a reliable tool to augment cerebral blood flow in tuberculosis-related stenoocclusive changes of cerebral vasculature after the failure of endovascular procedures.

Clinical outcome after 450 revascularization procedures for moyamoya disease

Object

Moyamoya disease (MMD) is a rare cerebrovascular disease mainly described in the Asian literature. To address a lack of data on clinical characteristics and long-term outcomes in the treatment of MMD in North America, the authors analyzed their experience at Stanford University Medical Center. They report on a consecutive series of patients treated for MMD and detail their demographics, clinical characteristics, and long-term surgical outcomes.

Methods

Data obtained in consecutive series of 329 patients with MMD treated microsurgically by the senior author (G.K.S.) between 1991 and 2008 were analyzed. Demographic, clinical, and surgical data were prospectively gathered and neurological outcomes assessed in postoperative follow-up using the modified Rankin Scale. Association of demographic, clinical, and surgical data with postoperative outcome was assessed by chi-square, uni- and multivariate logistic regression, and Kaplan-Meier survival analyses.

Results

The authors treated a total of 233 adult patients undergoing 389 procedures (mean age 39.5 years) and 96 pediatric patients undergoing 168 procedures (mean age 10.1 years). Direct revascularization technique was used in 95.1% of adults and 76.2% of pediatric patients. In 264 patients undergoing 450 procedures (mean follow-up 4.9 years), the surgical morbidity rate was 3.5% and the mortality rate was 0.7% per treated hemisphere. The cumulative 5-year risk of perioperative or subsequent stroke or death was 5.5%. Of the 171 patients presenting with a transient ischemic attack, 91.8% were free of transient ischemic attacks at 1 year or later. Overall, there was a significant improvement in quality of life in the cohort as measured using the modified Rankin Scale (p < 0.0001).

Conclusions

Revascularization surgery in patients with MMD carries a low risk, is effective at preventing future ischemic events, and improves quality of life. Patients in whom symptomatic MMD is diagnosed should be offered revascularization surgery.

Understanding and treating moyamoya disease in children

Moyamoya disease, a known cause of pediatric stroke, is an unremitting cerebrovascular occlusive disorder of unknown etiology that can lead to devastating, permanent neurological disability if left untreated. It is characterized by progressive stenosis of the intracranial internal carotid arteries and their distal branches and the nearly simultaneous appearance of basal arterial collateral vessels that vascularize hypoperfused brain distal to the occluded vessels. Moyamoya disease may be idiopathic or may occur in association with other syndromes. Most children with moyamoya disease present with recurrent transient ischemic attacks or strokes. Although there is no definitive medical treatment, numerous direct and indirect revascularization procedures have been used to improve the compromised cerebral circulation, with outcomes varying according to procedure type. Such techniques improve the long-term outcome of patients with both idiopathic and syndrome-associated moyamoya disease. This review provides a comprehensive discussion of moyamoya disease in children, with an emphasis on the most effective surgical treatment options.

Age-dependent revascularization patterns in the treatment of moyamoya disease in a European patient population

Object

Different revascularization procedures are used in the treatment of patients with moyamoya disease (MMD). The aim of this study was to investigate the relative contribution of direct and indirect revascularization procedures to the restoration of collateral blood supply in adult and pediatric patients with MMD.

Methods

The authors performed 39 combined cerebral revascularization procedures (standard extraintracranial bypass [STA-MCA bypass] plus encephalomyosynangiosis [EMS]) in 10 pediatric and 10 adult patients. All patients underwent physical examination and digital subtraction angiography before and 6 months after surgery. The STA-MCA bypass and EMS function were graded as Grade I (poor), II (moderate), or III (good) on the basis of the angiograms.

Results

In pediatric patients, bypass function was Grade I in 12, Grade II in 8, and Grade III in 0 hemispheres; EMS function was Grade I in 0, Grade II in 12, and Grade III in 8 hemispheres. In the adult patients, bypass function was Grade I in 8, Grade II in 8, and Grade III in 3 hemispheres; EMS function was Grade I in 10 hemispheres, Grade II in 5, and Grade III in 1 hemisphere. In the pediatric patients disease was classified as improved in 14 hemispheres on the basis of clinical results and stable in 6. In the adults it was classified as improved in 12 hemispheres stable in 7 hemispheres.

Conclusions

Combined revascularization led to good angiographic and clinical results in both patient populations. Especially in pediatric patients, EMS represents a suitable alternative to bypass surgery.

Moyamoya disease: current concepts and future perspectives

Moyamoya disease is an uncommon cerebrovascular disease that is characterised by progressive stenosis of the terminal portion of the internal carotid artery and its main branches. The disease is associated with the development of dilated, fragile collateral vessels at the base of the brain, which are termed moyamoya vessels. The incidence of moyamoya disease is high in east Asia, and familial forms account for about 15% of patients with this disease. Moyamoya disease has several unique clinical features, which include two peaks of age distribution at 5 years and at about 40 years. Most paediatric patients have ischaemic attacks, whereas adult patients can have ischaemic attacks, intracranial bleeding, or both. Extracranial-intracranial arterial bypass, including anastomosis of the superficial temporal artery to the middle cerebral artery and indirect bypass, can help prevent further ischaemic attacks, although the beneficial effect on haemorrhagic stroke is still not clear. In this Review, we summarise the epidemiology, aetiology, clinical features, diagnosis, surgical treatment, and outcomes of moyamoya disease. Recent updates and future perspectives for moyamoya disease will also be discussed.

Superficial temporal artery to middle cerebral artery bypass: past, present, and future

OBJECT

The aim of this study was to review the historical developments and current status of superficial temporal artery (STA) to middle cerebral artery (MCA) bypass.

METHOD

A literature review was performed to review the origins and current uses of the STA bypass procedure in neurosurgery.

RESULTS

The idea of providing additional blood supply to the brain to prevent stroke and maintain neurological function has been present in the mind of neurosurgeons for many decades. In 1967 the first STA-MCA bypass was done by M. G. Yaşargil, and an enormous step was made into the field of microneurosurgery and cerebral revascularization. During the decades that followed, this technique was used as an adjuvant or a definitive surgical treatment for occlusive disease of the extracranial and intracranial cerebral vessels, skull base tumors, aneurysms, carotid-cavernous fistulas, cerebral vasospasm, acute cerebral ischemia, and moyamoya disease. With the results of the first randomized extracranial-intracranial (EC-IC) bypass trial and the development of endovascular techniques such as angioplasty for intracranial atherosclerotic disease and cerebral vasospasm, the indications for STA-MCA bypass became limited. Neurosurgeons continued to perform EC-IC bypasses as an adjuvant to clipping of aneurysms and in the treatment of skull base tumors and moyamoya disease; the procedure is less commonly used for atherosclerotic carotid artery occlusion (CAO) with definite evidence of hemodynamic insufficiency. The evidence that patients with symptomatic CAO and "misery perfusion" have an increased stroke risk has prompted a second trial for evaluating EC-IC bypass for stroke prevention. The Carotid Occlusion Surgery Study is a new trial designed to determine whether STA-MCA bypass can reduce the incidence of stroke in these patients. New trials will also reveal the role of the STA-MCA bypass in the prevention of hemorrhages in moyamoya disease.

CONCLUSIONS

The role of STA-MCA bypass in the management of cerebrovascular disease continues to be refined and evaluated using advanced imaging techniques and by performing randomized trials for specific purposes, including symptomatic CAO.

Flow-assisted surgical cerebral revascularization

✓Extracranial–intracranial bypass surgery has advanced from a mere technical feat to a procedure requiring careful patient selection and a justifiable decision-making paradigm. Currently available technologies for flow measurement in the perioperative and intraoperative setting allow a more structured and analytical approach to decision making. The purpose of this report is to review the use of flow measurement in cerebral revascularization, presenting algorithms for flow-assisted surgical planning, technique, and surveillance.

Moyamoya disease in pediatric patients: outcomes of neurosurgical interventions

✓Neurosurgical interventions for moyamoya disease (MMD) in pediatric patients include direct, indirect, and combined revascularization procedures. Each technique has shown efficacy in the treatment of pediatric MMD; however, no single study has demonstrated the superiority of one technique over another. In this review, the authors explore the various studies focused on the use of these techniques for MMD in the pediatric population. They summarize the results of each study to clearly depict the clinical outcomes achieved at each institution that had utilized direct, indirect, or combined techniques. In certain studies, multiple techniques were used, and the clinical or radiological outcomes were compared accordingly.

Direct techniques have been shown to aid a reduction in perioperative strokes and provide immediate revascularization to ischemic areas; however, these procedures are technically challenging, and not all pediatric patients are appropriate candidates. Indirect techniques have also shown efficacy in the pediatric population but may require a longer period for revascularization to occur and perfusion deficits to be reversed. The authors concluded that the clinical efficacy of one technique over another is still unclear, as most studies have had small populations and the same outcome measures have not been applied. Authors who compared direct and indirect techniques noted approximately equal clinical outcomes with differences in radiological findings. Additional, larger studies are needed to determine the advantages and disadvantages of the different techniques for the pediatric age group.

Moyamoya angiopathy in Europe: the beginnings in Zurich, practical lessons learned, increasing awareness and future perspectives

The number of patients, especially children, diagnosed with Moyamoya angiopathy and being referred to us for treatment from all across Europe, has increased over the last few years. An increase in awareness of the occurrence of stroke in children in the general and medical population might be the main cause of this phenomenon. Increasing awareness does not happen "spontaneously" nor does it manifest overnight! It requires regular platforms of communication between the general population and amongst the different medical specialists mainly neurologists, paediatric neurologists, neuropsychologists, neuroradiologists, neurorehabilitation specialists, nursing staff and neurosurgeons. Presently we were lucky to conduct the first Moyamoya Symposium ever to be conducted at a European-Japanese level with participation of specialists of this particular field from across Europe and Japan. Ever since the first child with Moyamoya was managed at the University hospital in Zurich some 7 years ago the number of patients referred to us from all across Europe increased rapidly. The importance of interdisciplinary communication, trust and support amongst specialists and increasing the awareness of the disease among the patients, medical personnel was and remains to be just as important as making the correct diagnosis and treatment of choice in these patients. We present the lessons we learned during these previous years and look into the future perspectives that require our further and urgent attention.

Surgical results in pediatric moyamoya disease: Angiographic revascularization and the clinical results

OBJECTIVE

We retrospectively reviewed the pediatric patients with moyamoya disease (MMD) who underwent bypass surgery at our institution to compare the surgical results according to the surgical procedures.

PATIENTS AND METHODS

There were 24 total patients (age range: 2-15 years; mean age: 8.2 years). Twelve patients underwent encephalo-duro-arterio-synangiosis (EDAS) on 16 sides, 5 patients underwent encephalo-duro-arterio-myo-synangiosis (EDAMS) on 8 sides and 7 patients underwent combined superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis with EDAMS (STA-MCA-EDAMS) on 12 sides. The postoperative results were evaluated between 4 months and 5 years following surgery in terms of the angiographic revascularization and the clinical outcome.

RESULTS

EDAMS, regardless of the combined STA-MCA anastomosis, was significantly effective for achieving a good extent of the postoperative angiographic revascularization as compared with simple EDAS (P<0.05). STA-MCA-EDAMS tended to be better with respective to the relief of preoperative ischemic symptoms as compared with simple EDAS, although there was no significant statistical difference.

CONCLUSION

These results suggest that EDAMS with or without the combination of STA-MCA anastomosis was very useful for the formation of collateral circulation in comparison with simple EDAS for treating the pediatric patients with MMD, although these findings were not well correlated with the clinical outcomes.

Long term outcome in children with Moyamoya disease: experience with 16 patients

We present our experience with 16 children with Moyamoya disease/variant diagnosed at the Royal Alexandra Hospital for Children, Westmead, Sydney, Australia in the period between January 1982 and March 2004. Thirteen of these patients had one of the different revascularisation procedures. We reviewed the modes of presentation and the long-term outcome in these children. In our series the functional outcome was related to the functional status at presentation and was not related to the type of surgical procedure or age at presentation. We believe this is the largest reported series of Moyamoya disease/variant in Australia.

A ruptured middle cerebral artery aneurysm originating from the site of anastomosis 20 years after extracranial-intracranial bypass for moyamoya disease: case report

BACKGROUND

Direct revascularization through a superficial temporal artery-middle cerebral artery (STA-MCA) bypass is often performed to prevent ischemic or hemorrhagic attack in patients with moyamoya disease. This is the first reported case of aneurysm formation and rupture due to an STA-MCA bypass in a patient with moyamoya disease.

CASE DESCRIPTION

A 52-year-old man who had undergone bilateral STA-MCA bypass for caudate hemorrhage due to moyamoya disease 20 years previously suffered from sudden-onset unconsciousness. Computed tomography revealed a massive intracerebral hematoma (ICH) in the left frontoparietal region. Angiography showed good patency of the anastomoses and stage IV moyamoya disease. However, no other abnormality was found. Emergency evacuation of the hematoma was performed. The patient's postoperative course was uneventful, but consciousness disturbance of sudden onset occurred 1 month later. Computed tomography showed a hematoma in the lateral ventricle and acute hydrocephalus. Repeat angiography revealed an aneurysm on the left side of the anastomosis. Bilateral ventricle drainage tubes were inserted, and the aneurysm was clipped. A ventriculoperitoneal shunt was later performed.

CONCLUSION

In patients with moyamoya disease who have undergone extracranial-intracranial bypass surgery, progressive hemodynamic stress may cause the formation of de novo aneurysms after a postoperative period of several decades. Imaging examinations should therefore be performed periodically for follow-up, and a de novo aneurysm should be suspected in a patient who has an unusual ICH.

Revascularization of the posterior circulation

The primary objective of revascularization procedures in the posterior circulation is the prevention of vertebrobasilar ischemic stroke. Specific anatomical and neurophysiologic characteristics such as posterior communicating artery size affect the susceptibility to ischemia. Current indications for revascularization include symptomatic vertebrobasilar ischemia refractory to medical therapy and ischemia caused by parent vessel occlusion as treatment for complex aneurysms. Treatment options include endovascular angioplasty and stenting, surgical endarterectomy, arterial reimplantation, extracranial-to-intracranial anastomosis, and indirect bypasses. Pretreatment studies including cerebral blood flow measurements with assessment of hemodynamic reserve can affect treatment decisions. Careful blood pressure regulation, neurophysiologic monitoring, and neuroprotective measures such as mild brain hypothermia can help minimize the risks of intervention. Microscope, microinstruments and intraoperative Doppler are routinely used. The superficial temporal artery, occipital artery, and external carotid artery can be used to augment blood flow to the superior cerebellar artery, posterior cerebral artery, posterior inferior cerebellar artery, or anterior inferior cerebellar artery. Interposition venous or arterial grafts can be used to increase length. Several published series report improvement or relief of symptoms in 60 to 100% of patients with a reduction of risk of future stroke and low complication rates.

Moyamoya angiopathy in Europe

Over the past 6 years we at the Neurosurgery Department in Zürich have had the opportunity to manage increasing numbers of patients, especially children, with Moyamoya angiopathy. With increasing awareness of presence of this angiopathy in Europe the number of referrals from all across Europe is constantly on the increase. We have also been able to readdress the presence of the entity of Moyamoya angiopathy i.e. both the Moyamoya disease and the Moyamoya syndrome in the European population. Thorough presurgical workup is mandatory for evaluation of surgical candidates for the type of effective revascularisation procedure and therefore for their successful management. Apart from scrutinizing the routine yet indispensable presenting symptomatology with clinical examination of the patients, our preoperative diagnostic workup mainly consists of a 6 vessel cerebral angiography, cerebral perfusion studies with HMPAO-SPECT and H(2)15O-PET examinations and transcranial Doppler. Longterm follow-up of these patients is indispensable and of great interest to us in terms of etiology and progression of the disease process as well as the choice of effective revascularisation procedure especially in our European population.