Surgical outcomes for pediatric moyamoya: a systematic review and meta-analysis

Complications associated with combined direct and indirect bypass in Moyamoya Disease: A meta-analysis

Bypass revascularization helps prevent complications in Moyamoya Disease (MMD). To systematically review complications associated with combined direct and indirect (CB) bypass in MMD and analyze differences between the adult and pediatric populations. A systematic literature review was conducted per PRISMA guidelines. PUBMED, Cochrane Library, Web of Science, and CINAHL, were queried from January 1980 to March 2022. Complications were defined as any event in the immediate post-surgical period of a minimum 3 months follow-up. Exclusion criteria included lack of surgical complication reports, non-English articles, and CB unspecified or reported separately. 18 final studies were included of 1580 procured. 1151 patients (per study range = 10-150, mean = 63.9) were analyzed. 9 (50.0%) studies included pediatric patients. There were 32 total hemorrhagic, 74 total ischemic and 16 total seizure complications, resulting in a rate of 0.04 (95% CI 0.03, 0.06), 0.7 (95% CI 0.04, 0.10) and 0.03 (95% CI 0.02, 0.05), respectively. The rate of hemorrhagic complications in the pediatric showed no significant difference from the adult subgroup (0.03 (95% CI 0.01-0.08) vs. 0.06 (95% CI 0.04-0.10, p = 0.19), such as the rate of ischemic complications (0.12 (95% CI 0.07-0.23) vs. 0.09 (95% CI 0.05-0.14, p = 0.40). Ischemia is the most common complication in CB for MMD. Pediatric patients had similar hemorrhagic and ischemic complication rates compared to adults.

Influence of Patient and Technical Variables on Combined Direct and Indirect Cerebral Revascularization: Case Series

BACKGROUND

Cerebral bypass for flow augmentation is an important technique for selected neurosurgical patients, with multiple techniques used (direct, indirect, or combined).

OBJECTIVE

To assess the impact of patient and technical variables on direct and indirect bypass flow after combined revascularization.

METHODS

This was a retrospective, single-institution review of patients undergoing direct superficial temporal artery-to-middle cerebral artery bypass with indirect encephaloduro-myosynangiosis for moyamoya disease and steno-occlusive cerebrovascular disease over a 2-year period. We evaluated the effect of baseline patient characteristics, preoperative imaging characteristics, and operative variables on direct and indirect patency grades.

RESULTS

Twenty-six hemispheres (8 moyamoya disease and 18 steno-occlusive cerebrovascular disease) in 23 patients were treated with combined revascularization. The mean patient age was 53.4 ± 19.1 years. Direct bypass patency was 96%. Over a mean follow-up of 8.3 ± 5.4 months, there were 3 strokes in the treated hemispheres (11.5%). The mean modified Rankin Scale score improved from 1.3 ± 1.1 preoperatively to 0.7 ± 0.8 postoperatively. Preservation of the nondonor superficial temporal artery branch was associated with a lower direct bypass grade ( P < .01), whereas greater mean time to maximum perfusion (Tmax)> 4 and >6 seconds and mismatch volumes were associated with higher direct bypass grades ( P < .05). Tmax >4-second volume inversely predicted indirect bypass patency.

CONCLUSION

Patient and technical variables may influence the relative contributions of the direct and indirect components of combined revascularizations.

Surgical revascularizations for pediatric moyamoya: a systematic review, meta-analysis, and meta-regression analysis

INTRODUCTION

There is no clear consensus regarding the technique of surgical revascularization for moyamoya disease and syndrome (MMD/MMS) in the pediatric population. Previous meta-analyses have attempted to address this gap in literature but with methodological limitations that affect the reliability of their pooled estimates. This meta-analysis aimed to report an accurate and transparent comparison between studies of indirect (IB), direct (DB), and combined bypasses (CB) in pediatric patients with MMD/MMS.

METHODS

In accordance with PRISMA guidelines, systematic searches of Medline, Embase, and Cochrane Central were undertaken from database inception to 7 October 2022. Perioperative adverse events were the primary outcome measure. Secondary outcomes were rates of long-term revascularization, stroke recurrence, morbidity, and mortality.

RESULTS

Thirty-seven studies reporting 2460 patients and 4432 hemispheres were included in the meta-analysis. The overall pooled mean age was 8.6 years (95% CI: 7.7; 9.5), and 45.0% were male. Pooled proportions of perioperative adverse events were similar between the DB/CB and IB groups except for wound complication which was higher in the former group (RR = 2.54 (95% CI: 1.82; 3.55)). Proportions of post-surgical Matsushima Grade A/B revascularization favored DB/CB over IB (RR = 1.12 (95% CI 1.02; 1.24)). There was no significant difference in stroke recurrence, morbidity, and mortality. After meta-regression analysis, year of publication and age were significant predictors of outcomes.

CONCLUSIONS

IB, DB/CB are relatively effective and safe revascularization options for pediatric MMD/MMS. Low-quality GRADE evidence suggests that DB/CB was associated with better long-term angiographic revascularization outcomes when compared with IB, although this did not translate to long-term stroke and mortality benefits.

Wide Arterial Sparing Encephalo-Duro-Synangiosis for Moyamoya: Surgical Technique and Outcomes

BACKGROUND

Moyamoya is managed by surgical revascularization, but no standardized method has yet been universally adopted.

OBJECTIVE

To describe a new indirect bypass technique for pediatric moyamoya, wide arterial sparing encephalo-duro-synangiosis (WASEDS), which provides a much wider area of revascularization with minimal compromise to the middle meningeal arterial tree compared with traditional procedures. Initially used as a salvage technique after failed encephalo-duro-arterio-synangiosis, its success later motivated its use as a first-line procedure.

METHODS

Clinical and radiographic records of patients who underwent WASEDS for moyamoya from 2009 to 2020 were reviewed. Brain perfusion relative cerebral blood volume on the side of the WASEDS procedure was calculated. Two-tailed paired t tests were performed to identify the statistically significant differences ( P ≤ .05).

RESULTS

WASEDS was successfully performed on 8 patients for a total of 14 cerebral hemispheres. Age ranged from 2 to 25 years. There were no mortalities. The average clinical and radiographic follow-up was 49.79 months (range 2-126 months), demonstrating improvement in neurological condition and no postoperative stroke and significant diminution or cessation of transient ischemic attacks in all patients. Relative cerebral blood volume increased 9.24% after the WASEDS procedure ( P = .012). There were no neurological complications. There were 2 pseudomeningoceles related to the extensive dural openings.

CONCLUSION

WASEDS is a safe and effective indirect revascularization technique for both primary and salvage techniques. It provides an extensive area of cortical revascularization with no compromise of the middle meningeal vasculature and subjective reports of early improvement in cognition and behavior. The main disadvantage is elevated risk of pseudomeningocele secondary to the large craniotomy.

Angioarchitectural Factors Associated with Postoperative Cerebral Infarction in Ischemic Moyamoya Disease

Objective: To investigate the angioarchitectural factors associated with postoperative cerebral infarction in ischemic moyamoya disease. Methods: Data on patients who underwent surgery for ischemic MMD from 1 October 2015 to 31 October 2020, at Peking University International Hospital were collected and retrospectively analyzed. General conditions such as patient sex, age, site of surgery, preoperative manifestations such as TIA attack and old cerebral infarction, and seven angioarchitectural factors of the MMD based on DSA were selected and measured. Statistical analysis was performed by the Pearson chi-square statistic, analysis of variance (ANOVA), and multifactor logistic regression analysis. Results: Age (OR, 0.969; 95%CI, 0.939–1.000; p = 0.049), A1stenosis (OR, 5.843; 95%CI, 1.730–19.732; p = 0.004), M1stenosis (OR, 6.206; 95%CI, 2.079–18.526; p = 0.001), PCA anomalies (OR, 4.367; 95%CI, 1.452–13.129; p = 0.049), Unstable compensation (OR, 5.335; 95%CI, 1.427–19.948; p = 0.013), TIA (OR, 4.264; 95%CI, 1.844–9.863; p = 0.001), Old cerebral infarction (OR, 2.972; 95%CI, 1.194–7.397; p = 0.019). The above seven factors can be used in the regression equation to predict the probability of postoperative cerebral infarction. The prediction accuracy is 90.2%. Conclusions: Age, TIA attack, old cerebral infarction, and five angioarchitectural factors of MMD are strongly associated with postoperative cerebral infarction. Seven factors, including age, TIA attack, old infarction, and four angioarchitectural factors, can be taken to quantify the probability of surgical cerebral infarction in MMD.

Pediatric Stroke from Bench to Bedside: A Single-Center Experience in Saudi Arabia

Purpose

Stroke is a leading cause of severe long-term disability and death worldwide. This study aimed to determine the genetic background, causative factors, and diagnostic and outcome measures of pediatric stroke in an area endemic to sickle cell disease (SCD).

Patients and Methods

This retrospective review analyzed pediatric patients with acute stroke who were admitted to King Fahd Hospital of the University, Eastern Province, Saudi Arabia, between January and June 2019. We assessed 49 cases based on computed tomography (CT) and magnetic resonance imaging (MRI) findings. Patients with incomplete records or unavailable radiological images were excluded.

Results

A high likelihood of familial coexistence of stroke was detected in patients with affected siblings (33%). Among various central nervous system manifestations, motor weakness (28.6%) and headache (20.4%) were the most common symptoms/signs. Hypoxic-ischemic encephalopathy (HIE) (28.6%), SCD (22.5%), and moyamoya disease (14.3%) were the most prevalent underlying etiologies. CT without intravenous contrast was the most used initial imaging technique (92.5%). An arterial blockage was more prevalent (53.4%) than a venous infarct (46.6%) (p = 0.041), while arterial ischemic stroke was more prevalent (56.5%) than hemorrhagic stroke (43.5%). The middle cerebral artery (MCA) was most affected (63.5%), followed by the anterior cerebral artery (22.7%) and posterior cerebral artery (13.6%). Most patients were managed with medical treatment (86.1%). No mortalities occurred during the initial hospital stay. The mean length of hospital stay was 12 days.

Conclusion

HIE was the most prevalent etiology of pediatric stroke. Motor weakness and headache were the most common initial manifestations. Arterial ischemic stroke was more prevalent than venous or hemorrhagic stroke. Considering the rarity of pediatric stroke, future studies should be performed with a aborative effort nationally and internationally.

Absence of the RNF213 p.R4810K variant may indicate a severe form of pediatric moyamoya disease in Japanese patients

OBJECTIVE

The authors' objective was to investigate the influence of the RNF213 p.R4810K variant on the clinical presentation and outcomes of Japanese pediatric patients with moyamoya disease.

METHODS

A total of 129 Japanese patients with pediatric-onset moyamoya disease (onset age ≤ 15 years) who visited the authors' department from 2012 to 2020 participated in this study. After RNF213 p.R4810K genotyping of each patient was performed, the relationship between genotype and clinical presentation or outcomes, including onset age, initial presentation, surgical outcomes, and subsequent cerebrovascular events, was evaluated. Patients without the p.R4810K variant were tested for RNF213 variants other than p.R4810K. The authors especially focused on the results of patients who presented with moyamoya disease at younger than 1 year of age (infantile onset).

RESULTS

Compared with the patients with heterozygous variants, patients without the p.R4810K variant were younger at onset (7.1 ± 3.7 vs 4.4 ± 0.9 years), and all 4 patients with infantile onset lacked the p.R4810K variant. A greater proportion of patients without the p.R4810K variant presented with infarction than patients with the heterozygous variant (24.0% vs 7.6%) and a decreased proportion presented with transient ischemic attack (36.0% vs 71.7%). No significant correlation was observed between p.R4810K genotype and clinical outcomes, including surgical outcomes and subsequent cerebrovascular events; however, a decreased proportion of patients without the p.R4810K variant had good surgical outcomes compared with that of patients with the heterozygous variant (76.5% vs 92.2%). Among the 25 patients without the p.R4810K variant, 8 rare variants other than p.R4810K were identified. Three of 4 patients with infantile onset had RNF213 variants other than p.R4810K, which had a more severe functional effect on this gene than p.R4810K.

CONCLUSIONS

Absence of the RNF213 p.R4810K variant may be a novel biomarker for identification of a severe form of pediatric moyamoya disease.

Encephaloduroarteriosynangiosis Operative Technique and Intraoperative Anesthesia Management: Treatment From Both Sides of the Curtain

BACKGROUND

Encephaloduroarteriosynangiosis (EDAS) is a form of indirect revascularization for cerebral arterial steno-occlusive disorders. EDAS has gained growing interest as a technique applicable to pediatric and adult populations for several types of ischemic cerebral steno-occlusive conditions.

OBJECTIVE

To present a team-oriented, multidisciplinary update of the EDAS technique for application in challenging adult cases of cerebrovascular stenosis/occlusion, successfully implemented in more than 200 cases.

METHODS

We describe and demonstrate step-by-step a multidisciplinary-modified EDAS technique, adapted to maintain uninterrupted intensive medical management of patients' stroke risk factors and anesthesia protocols to maintain strict hemodynamic control.

RESULTS

A total of 216 EDAS surgeries were performed in 164 adult patients, including 65 surgeries for patients with intracranial atherosclerotic disease and 151 operations in 99 patients with moyamoya disease. Five patients with intracranial atherosclerotic disease had recurrent strokes (3%), and there was one perioperative death. The mean clinical follow-up was 32.9 mo with a standard deviation of 31.1. There was one deviation from the surgical protocol. There were deviations from the anesthesia protocol in 3 patients (0.01%), which were promptly corrected and did not have any clinical impact on the patients' condition.

CONCLUSION

The EDAS protocol described here implements a team-oriented, multidisciplinary adaptation of the EDAS technique. This adaptation resides mainly in 3 points: (1) uninterrupted administration of intensive medical management, (2) strict hemodynamic control during anesthesia, and (3) meticulous standardized surgical technique.

Progression in Moyamoya Disease: Clinical Feature, Neuroimaging Evaluation and Treatment

Moyamoya disease (MMD) is a chronic cerebrovascular disease characterized by progressive stenosis of the arteries of the circle of Willis, with the formation of collateral vascular network at the base of the brain. Its clinical manifestations are complicated. Numerous studies have attempted to clarify the clinical features of MMD, including its epidemiology, genetic characteristics, and pathophysiology. With the development of neuroimaging techniques, various neuroimaging modalities with different advantages have deepened the understanding of MMD in terms of structural, functional, spatial, and temporal dimensions. At present, the main treatment for MMD focuses on neurological protection, cerebral blood flow reconstruction, and neurological rehabilitation, such as pharmacological treatment, surgical revascularization, and cognitive rehabilitation. In this review, we discuss recent progress in understanding the clinical features, in the neuroimaging evaluation and treatment of MMD.

Pediatric Stroke: Overview and Recent Updates

Stroke can occur at any age or stage in life. Although it is commonly thought of as a disease amongst the elderly, it is important to highlight the fact that it also affects infants and children. In both populations, strokes have a high rate of morbidity and mortality. Arguably, it is more detrimental in the pediatric population given the occurrence at a younger age and therefore, a longer duration of disability, potentially over the entire lifespan. The high rate of morbidity and mortality in pediatrics is attributed to significant delays in diagnosis, as well as misdiagnosis. Acute stroke management is time dependent. Patients who receive acute treatment with either intravenous (IV) tissue plasminogen activator (tPA) or mechanical thrombectomy, have improved mortality and functional outcomes. Additionally, the earlier treatment is initiated, the higher the likelihood of preserving penumbra, restoring cerebral blood flow and potentially reversing symptoms, thereby limiting disability. Prompt identification is essential as it leads to improved patient care in such a narrow therapeutic window. It enhances the care received during hospitalization and reduces the risk of early stroke recurrence. Despite limited data and lack of large randomized clinical trials in pediatrics, both IV tPA and mechanical thrombectomy have been successfully used. Bridging the gap of acute stroke management in the pediatric population is an essential part of minimizing adverse outcomes. In this review, we discuss the epidemiology of pediatric stroke, the diverse etiologies, presentation as well as both acute and preventative management.

Risk factors for postoperative ischemic complications in pediatric moyamoya disease

Background

Ischemic events are the most common postoperative complication in bypass surgery for moyamoya disease (MMD), but the risk factors for pediatric MMD remain unclear. The goal of the study was to investigate the risk factors for postoperative ischemic complications in pediatric MMD patients.

Methods

We retrospectively reviewed a consecutive series of pediatric MMD cases at Beijing Tiantan Hospital, Capital Medical University from June 2010 through June 2019. Preoperative clinical variables and radiographic findings were recorded, and logistic regression analysis was carried out to identify the risk factors for postoperative ischemic events.

Results

A total of 533 operations in 336 patients were included in this study. Postoperative complications occurred after 51 operations (9.6%), including 40/447 indirect bypass procedures, 9/70 direct bypass procedures, and 2/16 combined bypass procedures. Postoperative ischemic events were the most common complication and occurred in 30 patients after 31 procedures (8.9% per patient; 5.8% per operation), including 26/447 indirect bypass procedures, 4/70 direct bypass procedures, and 1/16 combined bypass procedures, and the incidence of these events did not differ significantly between indirect and non-indirect bypass (5.8% vs 5.8%; p = 0.999). Multivariate logistic regression analyses revealed that older age at operation (OR 1.129, 95% CI 1.011–1.260, p = 0.032) and posterior cerebral artery involvement (OR 2.587, 95% CI 1.030–6.496, p = 0.043) were significantly associated with postoperative ischemic events.

Conclusion

We speculate that older age at operation and posterior cerebral artery involvement are risk factors for postoperative ischemic events in pediatric MMD patients.

Clinical Usefulness of Genetic Testing For Patients with Moyamoya Disease: A Systematic Review

BACKGROUND

The effect of genetic factors on presentation and outcomes of moyamoya disease (MMD) is unclear. We aimed to examine differences in presentation of MMD by genetic variant, delineate the influence of genetic factors on outcomes, and characterize the applicability of genetic testing to management.

METHODS

A systematic review was conducted using the PubMed, Embase, and Scopus databases. Title/abstract screening, full-text screening, and data extraction were conducted.

RESULTS

Of 1329 articles, 12 were included. Genes included RNF213 (ring finger protein 213), VEGF (vascular endothelial growth factor), and soluble VEGR receptor (sVEGFR) 1 and 2. Patients heterozygous and homozygous for the p.R1480K variant of RNF213 had younger age of onset; were more frequently familial, had posterior cerebral artery involvement, had bilateral lesions; and were more likely to present with cerebral infarction or transient ischemic attack. The heterozygous p.4810K variant is associated with improved postoperative collateral formation. Stroke recurrence, stroke-free survival, neurologic status, and functional condition after surgery are not associated with the p.4180K genotype. Patients homozygous for p.4180K more frequently experience long-term cognitive impairment. Patients with the C/C genotype of VEGF 2634 or decreased sVEGFR-1 and sVEGFR levels postoperatively had greater postoperative collateral formation.

CONCLUSIONS

Genetic factors correlate with MMD presentation including age of onset, severity, and symptoms, and angiographic and clinical outcomes after surgery. Incorporation of genetic testing panels into practice may allow for risk stratification, management, and follow-up of children and adults with MMD. However, future studies are necessary to validate the usefulness of genetic testing for MMD before this situation occurs.

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.

Preoperative Risks of Cerebral Infarction in Pediatric Moyamoya Disease

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Encephaloduroarteriosynangiosis with Dural Inversion for Moyamoya Disease in a Pediatric and Adult Population-a Single-Center 20-Year Experience

BACKGROUND

Moyamoya disease refers to a progressive vasostenotic or vaso-occlusive disease that puts patients at risk for ischemic and/or hemorrhagic events. Surgical revascularization procedures aim to restore cerebral blood flow to mitigate stroke risk and functional decline. Direct and indirect bypass procedures have been proposed. Encephaloduroarteriosynangiosis (EDAS) with dural inversion is a well-accepted indirect procedure.

METHODS

Patients with moyamoya disease undergoing EDAS with dural inversion between 2000 and 2019 were retrospectively reviewed. Clinical data including short-term and long-term outcome were measured using the modified Rankin Scale. Patient satisfaction was assessed in patients with a minimum of 3 years of clinical follow-up.

RESULTS

Over a 20-year period, 54 patients underwent 88 EDAS with dural inversion procedures. Most patients underwent bilateral surgery (34/54 patients, 63.0%). Median age at surgery was 19 years (range, 1-63 years) with a median follow-up of 6 years (range, 1-20 years). Periprocedural complications occurred in 4 of 54 patients (7.4%). Periprocedural infarction occurred in 3 of 88 operations (3.4%). Functional outcome at 90 days was favorable (modified Rankin Scale score 0-2) in 92.6% of cases. On long-term follow-up, 3 patients experienced ischemic infarction (5.6%), and 1 patient (1.9%) experienced hemorrhagic infarction. Patients' overall satisfaction with the surgical procedure at last follow-up was determined in 36 of 45 patients with at least 3 years of follow-up (response rate 80.0%). Median satisfaction was very good (score 5; range, 3-5).

CONCLUSIONS

EDAS with dural inversion is a safe and effective indirect revascularization procedure for pediatric and adult moyamoya disease that is associated with favorable long-term outcomes and high patient satisfaction.

Failures in Revascularization for Pediatric Moyamoya Disease and Syndrome: A Scoping Review

BACKGROUND

Moyamoya disease (MMD) and moyamoya syndrome (MMS) are a rare cause of stroke commonly managed surgically. We conducted a scoping review to identify the current scope of the literature regarding factors associated with failure of revascularization surgery for MMD and MMS in pediatric patients and to catalyze future research.

METHODS

A scoping review was conducted to explore failures of revascularization surgery for MMD and MMS in pediatric patients using the PubMed, Embase, and Scopus databases. Titles and abstracts returned from searches were screened for full-text review. Studies meeting inclusion criteria were reviewed in full, and relevant data were extracted.

RESULTS

Of 2450 resultant articles, 15 were included. Angiographic outcomes were reported for 900 hemispheres, of which 442 (49.1%) were denoted as Matsushima grade A, 299 (33.2%) as Matsushima grade B, and 159 (17.7%) as Matsushima grade C. Patients with MMS had poorer angiographic outcomes than did patients with MMD. Patients with poor neovascularization had a greater degree of moyamoya vessels on follow-up angiogram. Suzuki stage was not associated with angiographic outcome in individual patients. Angiographic outcomes differed by surgical approach and were not associated with clinical outcomes. Literature identifying factors was sparse.

CONCLUSIONS

The existing literature indicates that factors such as cause, degree of moyamoya vessels, and surgical approach may affect the likelihood of Matsushima grade C revascularization in pediatric patients with MMD and MMS. Future studies are necessary to definitively elucidate factors associated with failure of revascularization surgery for pediatric MMD.

Postoperative stroke and neurological outcomes in the early phase after revascularization surgeries for moyamoya disease: an age-stratified comparative analysis

Stroke and neurological outcomes in the early phase following revascularization for moyamoya disease (MMD) may depend on the patient's age. In this study, an age-stratified comparative analysis was performed to clarify this issue. We reviewed 105 MMD patients who underwent 179 revascularization surgeries. The demographic characteristics were collected in four age groups (≤ 5 and 6-17 years for pediatric patients and 18-49 and ≥ 50 years for adults). Additionally, we assessed the incidence of subsequent stroke and deterioration of modified Rankin Scale (mRS) score. Then, we evaluated predictors of postoperative stroke and mRS deterioration using logistic regression. The mean patient age was 26.2 ± 18.5 years. No significant difference in the incidence of postoperative stroke was observed between age groups; however, the incidence tended to be increased among patients aged ≤ 5 years (17.9%) and patients aged ≥ 50 years (16.7%). Deterioration of mRS scores was significantly associated with ages ≤ 5 years (17.9%) and ≥ 50 years (11.1%). Logistic regression showed that posterior cerebral artery involvement (odds ratio [OR], 4.6) and postoperative transient neurological events (TNEs) (OR, 5.93) were risk factors for postoperative stroke. Age ≤ 5 years (OR, 9.73), postoperative TNEs (OR, 7.38), and postoperative stroke (OR, 49) were identified as predictors of unfavorable neurological outcomes. The novel feature of this comparative analysis by age group is that membership in the early-childhood MMD patient group (under 5 years old) was an independent risk factor for unfavorable short-term neurological outcomes and was mainly associated with the incidence of postoperative severe cerebral infarction.

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.