Understanding and treating moyamoya disease in children

I saw the 'puff of smoke' sign before it vanished into thin air

Moyamoya is characterized as a non-atherosclerotic and non-inflammatory vasculopathy that leads to progressive stenosis of the intracranial internal carotid arteries as well as the Circle of Willis. While it can be idiopathic (Moyamoya disease) or associated with another condition (Moyamoya syndrome), there is a characteristic 'puff of smoke' sign that can be appreciated on cerebral angiography.

Magnetic Resonance Angiography Alone Is Insufficient for Diagnosis and Surgical Planning in Children With Moyamoya

BACKGROUND

The gold standard for evaluation of the severity of moyamoya vasculopathy is the Suzuki grade determined with cerebral catheter angiography (CA). With greater use of magnetic resonance angiography (MRA) it is important to understand if MRA is truly comparable to CA.

METHODS

Children with moyamoya were evaluated using the Suzuki score for CA and the modified MRA six-stage Suzuki score to describe the angiographic findings in moyamoya from initial narrowing of the distal internal carotid artery to the "puff of smoke" appearance of the lenticulostriate collaterals and finally to the disappearance of this network of collaterals. Using Cohen kappa we compared Suzuki grade based on CA with MRA in the same patients.

RESULTS

A total of 27 children with moyamoya were reviewed. We calculated a weighted Cohen kappa of 0.49 (P < 0.0001), which is a moderate correlation.

CONCLUSIONS

We suggest caution in the reliance on MRA for the diagnosis and evaluation of severity of moyamoya in children.

Surgical revascularization as a procedure to prevent neurological complications in children with moyamoya syndrome associated with neurofibromatosis I: a single institution case series

BACKGROUND

The optimal timing and surgical approach for surgical revascularization in patients with moyamoya syndrome (MMS) associated with neurofibromatosis type I (NF1) remain so far elusive. We aimed to compare the long-term clinical, radiological, and cognitive effects of different revascularization procedures in a pediatric cohort of NF1-associated MMS.

METHODS

We reviewed the clinical, radiological, and surgical data of 26 patients with NF1-associated MMS diagnosed at our institution between 2012 and 2022, at the clinical onset and last follow-up.

RESULTS

Indirect bypasses were performed in 12/26 patients (57.1%), while combined direct and indirect procedures in 9/26 subjects (42.9%); 5 patients did not undergo surgery. Through logistic regression analysis, pathological Wechsler Intelligence Scale for Children (WISC) at onset was found to be associated with symptom improvement at 1-year follow up (p = 0.006). No significant differences were found in long-term neurocognitive outcome and stroke rate in patients receiving combined or indirect bypass (p > 0.05).

CONCLUSIONS

Currently, whether combined or indirect bypass should be considered the treatment of choice in pediatric patients with NF1-associated MMS remains unclear, as well as the optimal time approach. In our series, no significant differences were found in long-term neurocognitive outcome and stroke rate between patients treated with either of these two approaches. Clinical evidence supports the crucial role of early diagnosis and surgical revascularization in subjects with MMS-associated NF1, even in case of mildly symptomatic vasculopathy. This allows to achieve a good long-term outcome with improved intellectual function and prevention of stroke and seizure in these patients.

Direct Versus Indirect Revascularization for Moyamoya: a Large Multicenter Study

BACKGROUND

Moyamoya is a chronic occlusive cerebrovascular disease of unknown etiology causing neovascularization of the lenticulostriate collaterals at the base of the brain. Although revascularization surgery is the most effective treatment for moyamoya, there is still no consensus on the best surgical treatment modality as different studies provide different outcomes.

OBJECTIVE

In this large case series, we compare the outcomes of direct (DR) and indirect revascularisation (IR) and compare our results to the literature in order to reflect on the best revascularization modality for moyamoya.

METHODS

We conducted a multicenter retrospective study in accordance with the Strengthening the Reporting of Observational studies in Epidemiology guidelines of moyamoya affected hemispheres treated with DR and IR surgeries across 13 academic institutions predominantly in North America. All patients who underwent surgical revascularization of their moyamoya-affected hemispheres were included in the study. The primary outcome of the study was the rate of symptomatic strokes.

RESULTS

The rates of symptomatic strokes across 515 disease-affected hemispheres were comparable between the two cohorts (11.6% in the DR cohort vs 9.6% in the IR cohort, OR 1.238 (95% CI 0.651 to 2.354), p=0.514). The rate of total perioperative strokes was slightly higher in the DR cohort (6.1% for DR vs 2.0% for IR, OR 3.129 (95% CI 0.991 to 9.875), p=0.052). The rate of total follow-up strokes was slightly higher in the IR cohort (8.1% vs 6.6%, OR 0.799 (95% CI 0.374 to 1.709) p=0.563).

CONCLUSION

Since both modalities showed comparable rates of overall total strokes, both modalities of revascularization can be performed depending on the patient's risk assessment.

Transient ischemic attack after indirect revascularization surgery for pediatric patients with moyamoya disease: A retrospective study of intraoperative blood pressure

BACKGROUND

This study aimed to investigate the association between intraoperative blood pressure and postoperative transient ischemic attacks (TIAs) in pediatric patients with moyamoya disease after indirect revascularization surgery.

METHODS

We retrospectively reviewed the medical records of patients with moyamoya disease younger than 15 years who underwent indirect revascularizations under general anesthesia from 2013 to 2019. Perioperative clinical factors and intraoperative blood pressure data were collected and analyzed. Univariate and multivariable mixed-effect logistic regressions were used to identify predictors of postoperative TIA and symptom progression.

RESULTS

Among 444 hemispheres in 296 pediatric patients, 70 cases (16%) experienced postoperative TIAs within 2 weeks after surgery, and 34 cases (7.7%) developed postoperative symptom progression. Baseline mean blood pressure (MBP) (adjusted odds ratio, 1.261; 95% confidence interval, 1.037-1.528; P < 0.001), Average mean arterial pressure (MAP) (adjusted odds ratio, 1.137; 95% confidence interval, 1.052-1.228; P = 0.006), and Ipsilateral magnetic resonance angiography (MRA) score (adjusted odds ratio, 1.464; 95% confidence interval, 0.886-2.419; P = 0.012) were statistically significant risk factors for postoperative TIA. Average real variability of MAP (ARV-MAP), which were measures of intraoperative MAP variability (adjusted odds ratio, 4.731; 95% confidence interval, 1.419-15.257; P = 0.003) and maximum MAP declination (MaxD-MAP) (adjusted odds ratio, 1.271; 95% confidence interval, 1.013-1.520; P = 0.010) were statistically significant risk factors for postoperative symptom progression.

CONCLUSION

Higher pre-induction baseline blood pressure and ipsilateral MRA score were independent risk factors predicting postoperative TIA in pediatric patients with moyamoya disease after indirect revascularization. The high variability and drastic decline in intraoperative MAP showed predictive value in postoperative symptom progression.

Clinical significance of asymmetric venous vasculature on minimum-intensity projection in patients with moyamoya disease

This study analyzed the clinical significance and characteristics of asymmetric venous blood flow in patients with Moyamoya disease (MMD) using minimum intensity projection (minIP) susceptibility-weighted imaging. The minIP views of 30 patients diagnosed with MMD were retrospectively analyzed using clinical features, brain magnetic resonance angiography, electroencephalography, and brain single-photon emission computed tomography (SPECT). Simultaneously, differences between patients with acute cerebral infarction and non-MMD causes were analyzed. Twelve (40.0%) of the 30 patients had asymmetrical venous flow, which is usually seen in patients with acute cerebral infarction (P = .146). They also had significantly higher Suzuki stages than symmetric patients (P = .014), with five (41.7%) and three (25.0%) of them in stages 4 and 5, respectively. When the Suzuki stages of both hemispheres were different, more veins were found in the stenotic hemisphere (88.9%). Brain SPECT showed more severe hypoperfusion on the side with prominent vascularity in the minIP view (100.0%). Additionally, asymmetric blood flow was observed in 66.7% of the patients with cerebral infarction caused by MMD, whereas only 11.1% of the children with cerebral infarction caused by non-MMD had asymmetry (P = .005). Patients with MMD showed asymmetric hypointensity of the cortical veins with a minIP appearance. The venous structure showed greater signal loss on SWI and was more prominent in the hemisphere where stenosis was advanced or infarction occurred in other examinations. Cerebral infarction in patients with MMD tended to occur with asymmetrically prominent venous patterns with damaged areas in minIP images, which had distinct characteristics from those of patients without MMD.

Cerebral Perfusion in Pediatric Stroke: Children Are Not Little Adults

ABSTRACT

Cerebral perfusion imaging provides useful information about the hemodynamic state of the brain that is relevant to a number of neurologic conditions, including stroke, epilepsy, and brain tumors. Multiple imaging modalities have been developed to evaluate brain perfusion, primarily by the use of different tracers to measure cerebral blood volume and cerebral blood flow. Here, we provide an overview of magnetic resonance imaging perfusion techniques; summarize the role of perfusion imaging in adult stroke; describe changes in cerebral blood flow over childhood; and discuss the relevance and future directions of perfusion imaging in pediatric cerebrovascular disorders and stroke.

Pathophysiology of Vascular Stenosis and Remodeling in Moyamoya Disease

Moyamoya disease (MMD) and moyamoya syndrome (MMS) are progressive vascular pathologies unique to the cerebrovasculature that are important causes of stroke in both children and adults. The natural history of MMD is characterized by primary progressive stenosis of the supraclinoid internal carotid artery, followed by the formation of fragile collateral vascular networks. In MMS, stenosis and collateralization occur in patients with an associated disease or condition. The pathological features of the stenosis associated with MMD include neointimal hyperplasia, disruption of the internal elastic lamina, and medial attenuation, which ultimately lead to progressive decreases in both luminal and external arterial diameter. Several molecular pathways have been implicated in the pathophysiology of stenosis in MMD with functions in cellular proliferation and migration, extracellular matrix remodeling, apoptosis, and vascular inflammation. Importantly, several of these molecular pathways overlap with those known to contribute to diseases of systemic arterial stenosis, such as atherosclerosis and fibromuscular dysplasia (FMD). Despite these possible shared mechanisms of stenosis, the contrast of MMD with other stenotic pathologies highlights the central questions underlying its pathogenesis. These questions include why the stenosis that is associated with MMD occurs in such a specific and limited anatomic location and what process initiates this stenosis. Further investigation of these questions is critical to developing an understanding of MMD that may lead to disease-modifying medical therapies. This review may be of interest to scientists, neurosurgeons, and neurologists involved in both moyamoya research and treatment and provides a review of pathophysiologic processes relevant to diseases of arterial stenosis on a broader scale.

Current trends in pediatric moyamoya: a survey of international practitioners

OBJECTIVE

Moyamoya angiopathy (MM) is a chronic, progressive steno-occlusive arteriopathy of the distal internal carotid artery and its proximal branches. MM is recognized as a shared end-pathway common to a broad range of inciting pathologies, suggesting that tailored management is important. Pediatric MM differs from MM in adults. Currently, there are many uncertainties and controversies regarding the diagnosis and management of children with MM. Hence, we conducted an international survey to identify the contemporary management trends followed worldwide.

METHODS

A survey relating to lifestyle modifications, medical management, diagnosis, surgical management, and follow-up for pediatric MM was circulated across web-based platforms, through various international pediatric neurological and neurosurgical societies. Data collected included geographic region of practice, experience, responses to questions, and comments.

RESULTS

One hundred twenty-seven responses were evaluated (104 neurosurgeons and 23 neurologists, from 32 countries, across 6 continents). We found wide variations in the recommendations for management and lifestyle modification, with significant differences between regions of practice. Eighty percent recommend restrictions on physical activity, particularly for symptomatic and non-operated patients. Eighty-four percent prescribe aspirin. Sixty-five percent perform indirect revascularization. Seventy-eight percent recommend performing a staged surgery for bilateral MM. Only 26% perform acetazolamide challenge SPECT to evaluate brain perfusion. Only 15% of responders were from highly experienced centers.

CONCLUSION

This survey reflects the contemporary trends in management of pediatric MM, while highlighting the heterogeneity in the management approach of these patients. There is a need for multicenter, international studies to evaluate the safety, efficacy, and long-term outcome of various aspects of treatment of these patients.

A rare triad of morning glory disc anomaly, moyamoya vasculopathy, and transsphenoidal cephalocele: pathophysiological considerations and surgical management

Morning glory disc anomaly is a congenital abnormality of the optic disc and peripapillary retina reported as an isolated condition or associated with various anomalies, including basal encephaloceles and moyamoya vasculopathy. However, the co-occurrence of these three entities is extremely rare and the pathogenesis is still poorly understood. Moreover, data on the surgical management and long-term follow-up of the intracranial anomalies are scarce. Here, we describe the case of a 11-year-old boy with morning glory disc anomaly, transsphenoidal cephalocele, and moyamoya vasculopathy, who underwent bilateral indirect revascularization with encephalo-duro-myo-arterio-pericranio-synangiosis at the age of 2 years, and endoscopic repair of the transsphenoidal cephalocele at the age of 6 years. A rare missense variant (c.1081T>C,p.Tyr361His) was found in OFD1, a gene responsible for a X-linked ciliopathy, the oral-facial-digital syndrome type 1 (OFD1; OMIM 311200). This case expands the complex phenotype of OFD1 syndrome and suggests a possible involvement of OFD1 gene and Shh pathway in the pathogenesis of these anomalies.

Revascularisation surgery for paediatric moyamoya disease: The Singapore experience

Moyamoya disease (MMD) is characterized by the spontaneous occlusion of the distal internal carotid arteries and resultant neo-angiogenesis of fragile collateral blood vessels. Direct and indirect revascularization surgeries have shown to effectively reduce stroke risks in paediatric MMD, whereby the latter is a more utilised technique in children. This study was undertaken to determine the outcomes of revascularization in Singapore's multi-ethnic, Southeast Asian paediatric population. This is an ethics-approved study conducted in Singapore's 2 tertiary children hospital units: KK Women's and Children's Hospital and National University Hospital. Sixteen patients with a diagnosis of ischaemic-type MMD are recruited between 01 January 2002 to 31 January 2019; and a total of 24 surgeries are undertaken (24 cerebral hemispheres). There are 2 cases of stroke within 30 days post-surgery. However, no stroke recurrence is observed beyond 30 days after surgery in all patients. Four patients reported recurrent transient ischaemic attack symptoms in the follow-up period ranging from 3 months to 12 years. Data analyses show a statistically significant improvement in modified Rankin's Scale (mMRS) in post-operative patients from baseline to discharge, and at 3 months after surgery. Our study also observes that predictors of recurrent ischaemic events include higher pre-operative MRS, Suzuki stage and perioperative infarction. To the authors' knowledge, this is the first study to date reporting the outcomes of revascularisation in a paediatric Southeast Asian cohort.

Successful Surgical Management of Traumatic Intracranial Hemorrhaging After Revascularization Surgery for Moyamoya Vasculopathy: A Case Report and Review of Literature

BACKGROUND

Traumatic intracranial hemorrhaging associated with revascularization surgery for moyamoya vasculopathy is a potentially devastating problem that requires meticulous management, including surgery. However, only a few studies on this subject have been reported, and the clinical characteristics are poorly understood. We report a case of successful surgical management for a patient with traumatic intracranial hematoma managed with encephalo-duro-arterio-myo-synangiosis (EDAMS). The purpose of this article is to clarify the specific features of clinical scenarios, hemorrhagic sites, and operative techniques by reviewing all published cases.

CASE DESCRIPTION

A 10-year-old Japanese girl with a history of EDAMS for quasi-moyamoya disease was referred to our institution after minor head trauma. Cranial computed tomography scans revealed a right intracranial hematoma overlying the temporal muscle flap. After admission, hematoma developed, and emergency hematoma evacuation was performed. Venous hemorrhaging from the fascia of the temporal muscle flap was confirmed. Collaterals from indirect bypass were preserved in the surgery. Postoperative diffusion-weighted imaging revealed no ischemic complications. She immediately recovered and returned to her preinjury baseline.

CONCLUSION

In moyamoya vasculopathy, intrinsic collaterals or de novo anastomoses from revascularization surgery are easily injured, even with mild head trauma. Furthermore, the administration of antiplatelets agents increases the risk of hematoma development. Sacrifice of collaterals can lead to acute cerebral infarction. During emergency surgery for traumatic intracranial hematoma, a careful surgical strategy is needed to preserve the collateral supply.

Paediatric Moyamoya Disease and Tourette's Syndrome: An Unusual Association Responding Favourably to Direct and Indirect Cerebral Revascularisation Surgery

BACKGROUND

Moyamoya disease, an uncommon chronic intra-cerebral arteriopathy asymmetrically affecting the proximal vasculature, is rarely associated with clinical features pertaining to movement disorders.

CASE DESCRIPTION

A 5-year-and-9-month-old boy developed repetitive episodic involuntary winking of the right eye along with ipsilateral shoulder shrugging movements in an absolutely conscious state, associated with paroxysmal shouts and loud laughs and punctuated with abusive verbal expressions (coprolalia). These episodic features, over the course of the next 1.5 years, got progressively accentuated by situations which evoked stress. In addition, there was progressive regression of verbal and cognitive milestones, emotional lability and aspects of attention deficit hyperkinetic disorder. The child was evaluated by a neurologist with magnetic resonance imaging of the brain, which showed characteristic ischaemic areas involving the basal ganglia and fronto-parietal cortical areas along the middle cerebral artery territory, predominantly on the left side. Subsequent cerebral angiography revealed extensive stenosis of bilateral (predominantly left-sided) internal cerebral arteries and middle cerebral arteries with evidence of diffuse leptomeningeal collaterals. The electroencephalography was reported to be normal. He was eventually diagnosed to be suffering from Moyamoya disease with associated Tourette's syndrome. Subsequently, the child underwent left-sided superficial temporal artery to middle cerebral artery anastomosis along with encephalo-duro-arterio-myo-synangiosis. Significant clinico-radiological improvement was noted after 3 months. The clinical deficiencies had dramatically resolved. There was evidence of excellent development of both direct and indirect surgical collaterals along the left middle cerebral artery territory. He could go back to school.

CONCLUSION

Ours is probably the first case reporting an association of paediatric Moyamoya disease with Tourette's syndrome, which significantly resolved after cerebral revascularisation surgery.

Moyamoya disease in a Moroccan baby: a case report

Background

A stroke in a baby is uncommon, recent studies suggested that their incidence is rising. Moyamoya disease is one of the leading causes of stroke in babies. This condition is mostly described in Japan. In Morocco, moyamoya disease has rarely been reported and a few cases were published. We report a rare Moroccan case of a 23-month-old baby boy who presented with left-sided hemiparesis and was diagnosed as having moyamoya disease.

Case presentation

A 23-month-old full-term Moroccan baby boy born to a non-consanguineous couple was referred to our hospital with the complaint of sudden onset left-sided hemiparesis. On neurological examination, there were no signs of meningeal irritation, his gait was hemiplegic, tone was decreased over left side, power was 2/5 over left upper and lower limb, and deep tendon reflexes were exaggerated. Preliminary neuroimaging suggested an arterial ischemic process. Clinical and laboratory evaluation excluded hematologic, metabolic, and vasculitic causes. Cerebral angiography confirmed the diagnosis of moyamoya disease. Our patient was treated with acetylsalicylic acid 5 mg/kg per day and referred to follow-up with pediatric neurosurgeon. Cerebral revascularization surgery using encephaloduroarteriosynangiosis was performed. At 8-month follow-up, his hemiparesis had improved and no further ischemic events had occurred.

Conclusion

This case highlights the importance of considering moyamoya disease to be one of the classic etiologies of acute ischemic strokes in children from North Africa. It also emphasizes the rare presentation among the African population and the use of neurovascular imaging techniques to facilitate diagnosis of moyamoya disease.

Neuropsychological impacts of indirect revascularization for pediatric moyamoya disease

PURPOSE

Moyamoya disease (MMD) commonly leads to neurocognitive impairment. This study was carried out to show that temporal encephaloduroarteriosynangiosis (EDAS) has a positive neuropsychological impact on pediatric MMD patients.

METHODS

Fifty-five participants diagnosed with MMD from 2008 to 2014 were included in this retrospective study. The mean age at the preoperative evaluation was 9.5 years and the mean age at postoperative evaluation was 10.4. The average interval of initial and follow-up test was 10 months. K-WISC-III, Rey-Kim memory test, Children's Color Trails test (CCTT), Wisconsin Card Sorting Test (WCST), and Advanced Test of Attention (ATA) were used to evaluate patient's neurocognitive profile.

RESULTS

In this study, preoperative and postoperative neuropsychological fields were compared. Prior operation, pediatric MMD patients showed 54.2% deficit of inattention but only around 2.5% deficit in verbal memory recall function. There was a significant increase of performance IQ and PO score component of PIQ improved almost 10 scores after surgery. For memorial function, there was an improvement of approximately 10 scores in MQ after the surgery. This study also showed parietal activation following surgical treatment which enhanced the ability to interpret visual materials, to register and to retrieve visual information. Interestingly, despite the parietal cover surgery, there was a significant improvement of performance on WCST and CCTT measuring the prefrontal executive function. Concerning failure to maintain set, no significant postoperative improvements were made. However, simple and selective visual attention on ATA was significantly improved postoperatively.

CONCLUSIONS

The results from neuropsychological field comparison testifies the effectiveness of temporal EDAS in pediatric MMD patients. The surgery not only enhances the blood flow in operative regions, but it also improves the broad cerebral function including frontoparietal domains. Such alteration leads to overall advancement in cognitive function which are impaired due to MMD.

Moyamoya Disease in an 18-Month-Old Female Caucasian Complicated by Cerebral Hyperperfusion Syndrome Following Indirect Revascularization

BACKGROUND Cerebral hyperperfusion syndrome is a rare complication of indirect revascularization due to moyamoya disease, but has not been reported previously in the pediatric population. We present a case of an 18-month-old girl with moyamoya disease that was treated with bilateral pial synangiosis and had complications consistent with cerebral hyperperfusion syndrome. This case report discusses the pathophysiological mechanisms involved in cerebral hyperperfusion in moyamoya syndrome. CASE REPORT An 18-month-old female Caucasian presented with seizures and weakness of the left side. Angiography confirmed bilateral cerebral moyamoya disease that was worse on the right side. Indirect revascularization with pial synangiosis was first performed on the right side to allow for healing. Five months later, pial synangiosis was then performed on the left side. Postoperatively, the patient experienced increased intracranial pressure (ICP), suggesting cerebral hyperperfusion syndrome. She was treated with a repeat lumbar puncture, a lumbar drain, and a lumbar shunt. CONCLUSIONS This report demonstrates a case of cerebral hyperperfusion syndrome as a complication of moyamoya disease in a pediatric patient. Although the patient progressed well after placement of a lumbar shunt, this case demonstrates the occurrence of cerebral hyperperfusion syndrome as a complication of revascularization in pediatric patients and highlights the need for further research in this area.

Combination of Encephalo-Myo-Pial-Synangiosis and Encephalo-Arterio-Pial-Synangiosis Procedure in Pediatric Moya-Moya Disease

Background

Moya-moya disease in children is a cerebrovascular disorder that may cause cerebral ischemic or hemorrhage.

Case Details

We report an 8-year-old boy that was admitted with the chief complaint of repeated sudden half left body paralyze. MRA showed acute thrombotic infarction in the right hemisphere and internal carotid artery stenosis in the form of puffs of smokes. Indirect revascularization surgical procedure with combination of Encephalo-myo-pial-synangiosis (EMS) and Encephalo-arterio-pial-synangiosis (EAS) was performed. It resulted in a good response.

Conclusion

Moya-moya disease can lead to permanent neurological disability if untreated. Satisfactory outcome was noted following combination surgery management with EMS and EAS.

Reduction in Overt and Silent Stroke Recurrence Rate Following Cerebral Revascularization Surgery in Children with Sickle Cell Disease and Severe Cerebral Vasculopathy

BACKGROUND

Children with sickle cell disease (SCD) and moyamoya may benefit from indirect cerebral revascularization surgery in addition to chronic blood transfusion therapy for infarct prevention. We sought to compare overt and silent infarct recurrence rates in children with SCD undergoing revascularization.

METHODS

This was a retrospective cohort study of all children with SCD and moyamoya treated at two children's hospitals. Clinical events and imaging studies were reviewed.

RESULTS

Twenty-seven children with SCD and confirmed moyamoya receiving chronic transfusion therapy were identified, of whom 12 underwent indirect cerebral revascularization. Two subjects had postoperative transient ischemic attacks and another had a subarachnoid blood collection, none of which caused permanent consequences. Two subjects had surgical wound infections. Among these 12 children, the rate of overt and silent infarct recurrence decreased from 13.4 infarcts/100 patient-years before revascularization to 0 infarcts/100 patient-years after revascularization (P = 0.0057); the postrevascularization infarct recurrence rate was also significantly lower than the overall infarct recurrence of 8.87 infarcts/100 patient-years in 15 children without cerebral revascularization (P = 0.025).

CONCLUSIONS

The rate of overt and silent infarct recurrence was significantly lower following indirect cerebral revascularization. A prospective study of cerebral revascularization in children with SCD is needed.

Decompressive hemicraniectomy in the management of acute stroke in children with Moyamoya disease: the difficult balance between the spontaneous postoperative revascularization process and the need for cranial reconstruction

BACKGROUND AND IMPORTANCE

The decompressive hemicraniectomy (DCH) after malignant middle cerebral artery infarction in children is a rare procedure, and the indication is discussed as being controversial. Etiological Moyamoya disease has some additional challenges concerning the therapeutic strategy that have not mentioned in the recent literature, as it is dependent on special pathophysiology.

CLINICAL PRESENTATION

We report a case of a four-year-old patient with a decompressive hemicraniectomy after malignant middle cerebral artery infarction on the right hemisphere based on a Moyamoya syndrome with proximal MCA occlusions on both sides. After the decompression there was a good restitution of the hemiparesis, aphasia, and consciousness loss on admission. The bone flap replacement is usually done after three month in our department to ensure brain swelling has subsided. In this patient the cranioplasty was not arranged because of the development of collateral vessels to the right motor region through the craniotomy defect, to protect the supply of the eloquent cortex.

CONCLUSION

We conclude that the indication of DCH and postoperative treatment should be discussed individually, especially when neovascularisation developments can occur like in Moyamoya disease. An important point is the right timing for bone flap replacement, which should be directly after cerebral edema has subsided prior to the evolution of collaterals through the craniotomy defect. Additionally, leaving the opportunity for neovascularization through smaller defects has to be taken into account.

Network-based gene expression analysis of vascular wall of juvenile Moyamoya disease

SUBJECTS

Little is known about the pathology and pathogenesis of the Moyamoya disease (MMD). To better understand the molecular processes involved in MMD gene expression analysis of Moyamoya artery tissue to a control artery, this study was conducted.

METHODS

Tissue samples of two MMD and two non-MMD were profiled using oligonucleotide microarrays. Gene ontology classification of the differentially expressed genes was analyzed, and regulatory functional networks and pathways were identified with a network-based computational pathway analysis tool. Analysis of MMD and control tissue revealed 104 differentially expressed genes.

RESULTS

The two major significantly associated gene ontology terms was cellular development and cellular movement. Further network-based analysis showed significant interaction between RNF213 downstream gene networks and the top 3 score gene networks of MMD. Three major nodes of this network were evident in the merged network and were showing interactions with downstream network of RNF213.

CONCLUSIONS

Our results demonstrate that cellular development and cellular movement in MMD are the key role of mechanisms.

Preliminary study of neurocognitive dysfunction in adult moyamoya disease and improvement after superficial temporal artery-middle cerebral artery bypass

OBJECTIVE

Moyamoya disease (MMD) is a chronic cerebrovascular occlusive disease of unknown etiology. In addition, the neurocognitive impairment of adults with MMD is infrequently reported and, to date, has not been well described. We attempted to determine both the neurocognitive profile of adult moyamoya disease and whether a superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis can improve the neurocognitive impairment in exhibiting hemodynamic disturbance without stroke.

METHODS

From September 2010 through November 2012, 12 patients with angiographically diagnosed MMD underwent STA-MCA anastomosis for hemodynamic impairment. Patients with hypoperfusion and impaired cerebrovascular reserve (CVR) capacity but without evidence of ischemic stroke underwent a cognitive function test, the Seoul Neuropsychological Screening Battery (SNSB). Five patients agreed to undergo a follow-up SNSB test. Data from preoperative and postoperative neurocognitive function tests were compared and analyzed.

RESULTS

Five of 12 patients were enrolled. The median age was 45 years (range, 24-55 years). A comparison of preoperative to postoperative status of SNSB, memory domain, especially delayed recall showed significant improvement. Although most of the domains showed improvement after surgery, the results were not statistically significant.

CONCLUSION

In our preliminary study, large proportions of adult patients with MMD demonstrate disruption of cognitive function. This suggests the possibility of chronic hypoperfusion as a primary cause of the neurocognitive impairment. When preoperative and postoperative status of cognitive function was compared, memory domain showed remarkable improvement. Although further study is needed, neurocognitive impairment may be an indication for earlier intervention with reperfusion procedures that can improve cognitive function.

The maya behind moyamoya--the two extremes of the disease

Two children with moyamoya disease at the extremes of the disease- one with minimal clinical involvement and the other one with profound clinical features are reported with an interesting finding of the collaterals being the reason (maya) behind such varied presentations. To the best of authors' knowledge this is the first Indian report describing the reason behind the varied presentations of moyamoya disease.

Complex chromosome rearrangement of 6p25.3->p23 and 12q24.32->qter in a child with moyamoya

A 7-year-old white girl presented with left hemiparesis and ischemic stroke secondary to moyamoya syndrome, a progressive cerebrovascular occlusive disorder of uncertain but likely multifactorial etiology. Past medical history revealed hearing loss and developmental delay/intellectual disability. Routine karyotype demonstrated extra chromosomal material on 6p. Single nucleotide polymorphism microarray revealed a previously unreported complex de novo genetic rearrangement involving subtelomeric segments on chromosomes 6p and 12q. The duplicated/deleted regions included several known OMIM-annotated genes. This novel phenotype and genotype provides information about a possible association of genomic copy number variation and moyamoya syndrome. Dosage-sensitive genes in the deleted and duplicated segments may be involved in aberrant vascular proliferation. Our case also emphasizes the importance of comprehensive evaluation of both developmental delay and congenital anomalies such as moyamoya.

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.

Unpredictable postoperative global cerebral infarction in the patient of williams syndrome accompanying moyamoya disease

We report a rare case of Williams syndrome accompanying moyamoya disease in whom postoperative global cerebral infarction occurred unpredictably. Williams syndrome is an uncommon hereditary disorder associated with the connective tissue abnormalities and cardiovascular disease. To our knowledge, our case report is the second case of Williams syndrome accompanying moyamoya disease. A 9-year-old boy was presented with right hemiparesis after second operation for coarctation of aorta. He was diagnosed as having Williams syndrome at the age of 1 year. Brain MRI showed left cerebral cortical infarction, and angiography showed severe stenosis of bilateral internal carotid arteries and moyamoya vessels. To reduce the risk of furthermore cerebral infarction, we performed indirect anastomosis successfully. Postoperatively, the patient recovered well, but at postoperative third day, without any unusual predictive abnormal findings the patient's pupils were suddenly dilated. Brain CT showed the global cerebral infarction. Despite of vigorous treatment, the patient was not recovered and fell in brain death one week later. We suggest that in this kind of labile patient with Williams syndrome accompanying moyamoya disease, postoperative sedation should be done with more thorough strict patient monitoring than usual moyamoya patients. Also, we should decide the revascularization surgery more cautiously than usual moyamoya disease. The possibility of unpredictable postoperative ischemic complication should be kept in mind.

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.

Moyamoya disease associated with hereditary spherocytosis

A 5-year-old girl with hereditary spherocytosis presented with two episodes of transient ischemic attacks within a month. Cranial magnetic resonance imaging angiography revealed a left internal carotid artery and middle cerebral artery stenosis, with an extensive vascular mesh in the thalamic area indicative of moyamoya disease. Treatment consisted of supporting cerebral perfusion with blood transfusions, and splenectomy to prevent recurrence. Moyamoya disease is a very unusual cerebrovascular disorder in childhood and its association with hereditary spherocytosis is rarely reported.

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.