Background  Moyamoya vasculopathy is a rare neurological disease characterized by the progressive constriction of major intracranial vessels and secondary collateral formation. In the past decade, the popularity of combined bypass surgery has increased. They take advantage of the quick perfusion of direct bypass and collaterals ingrowth from indirect bypass. Objective  This study aimed to describe a single-center experience with surgical management of moyamoya disease (MMD) and moyamoya syndrome (MMS) over 7 years. Materials and Methods  In this retrospective medical records review, we enrolled patients diagnosed with MMD and MMS who were treated with combined surgical revascularization at the Hamad Medical Corporation center between 2015 and 2022. SPSS 26.0 was used to analyze the data. Results  A total of 20 patients were included, with 15% having MMS. The mean age was 37.4 ± 10.26 years, and 60% of them were males. The mean follow-up period was 13.6 months. The modified Rankin score was significantly decreased by 1.9 ± 2.1, p  = 0.0001. Following surgery, no deficits were observed in 16 cases, whereas three were not improved, and one died. Following up on the stroke status, one patient developed a hemorrhagic stroke, and another showed right-side numbness. The postoperative status was substantially linked with the initial clinical presentation ( p  = 0.004). Conclusion  Combined direct and indirect surgical revascularization procedures have favorable outcomes in MMD and MMS patients. Additional rigorous, prospective, controlled, high-quality trials with large-sample are needed to support our results.

OBJECTIVE: Surgery is the mainstay of stroke prevention in patients with symptomatic moyamoya disease (MMD). We present the results of a single-center retrospective study of indirect revascularization surgery for adult MMD, emphasizing angiographic outcomes, including dilation of the superficial temporal artery and formation of new collaterals.
METHODS: A prospectively maintained database of procedures performed for MMD was reviewed. Adult patients treated with indirect revascularization and with long-term angiographic follow-up were included. Preoperative and postoperative angiographic images and baseline and procedural characteristics were analyzed. A Wilcoxon signed-rank test was used to test the hypothesis that the superficial temporal artery increases in diameter postoperatively.
RESULTS: We identified 40 hemispheres in 27 patients, of which 35 had a sufficient angiographic follow-up. Bilateral procedures were performed on 16 patients. Most patients were female (72.5%), with a median age of 43 years old. The most common clinical presentation was ischemic stroke in 59.3% of cases. All patients underwent an encephaloduroarteriosynangiosis for treatment. A follow-up angiogram was performed at a median of 13.8 months postoperatively, showing superficial temporal artery (STA)-derived collaterals in 71.4% and collateral ingrowth via the burr holes in 61.8% of cases. Disease progression was evident in 34.3% of hemispheres. The normalized STA diameter was significantly increased postoperatively (2.4 to 3 mm; P < 0.05). A univariate analysis revealed that transdural collaterals and hyperlipidemia may affect collateral ingrowth from the STA, and no other patient- or procedure-related factors, including replacement of the bone flap, impacted on this.
CONCLUSIONS: A significant increase in STA diameter on follow-up angiography after encephaloduroarteriosynangiosis was found; however, this was not directly associated with STA collateral development. Rates of postoperative transient ischemic attacks were low, and no patients had a new ischemic or hemorrhagic stroke at last follow-up. The presence of transdural collaterals and the absence of hyperlipidemia were associated with STA collateral development on follow-up angiography, but the causality of this finding is unclear.

OBJECTIVE: To describe a surgical technique for posterior cerebral revascularization in pediatric patients with moyamoya arteriopathy. Here, we describe the clinical characteristics, surgical indications, operative techniques, and clinical and radiographic outcomes in a series of pediatric patients with moyamoya disease affecting the posterior cerebral artery (PCA) territory.
METHODS: A retrospective single-center series of all pediatric patients with moyamoya disease who presented to our institute between July 2009 through August 2019 were reviewed. The clinical characteristics, surgical indications, operative techniques, and long-term clinical and radiographic outcomes of pediatric moyamoya patients with PCA territory ischemia were collected and analyzed.
RESULTS: A total of 10 PCA revascularization procedures were performed in 9 patients, 5 female, ages 1 to 11.1 years (average 5.2 years). Complications included 1 stroke, with no infections, hemorrhages, seizures, or deaths. One patient had less than 1 year of radiographic and clinical follow-up. In 8 of 9 patients with at least 1 year of radiographic follow-up, there was engraftment of surgical vessels present in all cases. No new strokes were identified on long-term follow-up despite the radiographic progression of the disease. In the 8 cases available for analysis, the average follow-up was 50.8 months with a range of 12 to 117 months.
CONCLUSIONS: PCA territory ischemia in patients with progressive moyamoya disease can be surgically treated with indirect revascularization. Here, we describe our experience with PCA revascularization procedures for moyamoya disease, including pial pericranial dural (PiPeD) revascularization and pial synangiosis utilizing the occipital artery. These surgical options may be useful for decreasing the risk of stroke in pediatric moyamoya patients with severe posterior circulation disease.

Moyamoya syndrome (MMS) is a progressive disease that can result in debilitating strokes. Surgical revascularization is the mainstay of treatment. Selection of the proper bypass technique depends on the vascular anatomy and location of the hypoperfused cerebral territory. We describe here a case of successful indirect bypass utilizing a pericranial flap as well as dural inversion. A seven-month-old female was transferred from an outside facility to our institution for further evaluation and surgical treatment of MMS. She presented with bilateral brain infarcts worse on the left, with right-sided body weakness. After medical stabilization and hyperhydration, she was taken to the operating room for a left-sided indirect bypass. The superficial temporal artery (STA) was traced utilizing doppler but was determined to be too diminutive for transposition, so the decision was made to proceed with encephalo-duro-pericranio-synangiosis (EDPS). A pericranial graft was successfully affixed to the cortical surface in the hypoperfused middle cerebral artery (MCA) territory, and the dura was inverted. Postoperatively, the patient developed a pseudomeningocele, so a revision surgery was performed. She was discharged shortly after this and returned for encephalo-duro-arterio-synangiosis (EDAS) of the contralateral side. She followed up three months after her initial bypass surgery at age 10 months and was crawling without any focal deficits. She was lost to follow-up thereafter. EDPS is a safe technique for infants with MMS whose STA is too diminutive to be used for bypass surgery. This may be an effective method for indirect bypass in these patients.

The purpose of this study was to analyze factors affecting good neovascularization after indirect bypass surgery.
From August 2000 to July 2020, postoperative image results and medical records of 132 patients (159 hemispheres) who underwent EDAS of indirect bypass surgery at two institutions were reviewed retrospectively. Based on DSA results, angiogenesis after indirect bypass was divided into \"good\" or \"poor\" according to the Matsushima criteria. STA flap length affecting GPN were analyzed in the entire group (n = 159) and a MMD group (n = 134).
In the entire group, GPN after EDAS was observed in 94 (59.1%) hemispheres. Age, MMD, hypertension, and bone flap size were identified as significant factors in univariate analysis. Also, in the MMD group, 86 (64.2%) hemispheres showed GPN. Hypertension and bone flap size were significant factors in both univariate and multivariate analyses. Cutoff values of bone flap size and GPN were 47.91 cm2 in the entire group and the MMD group.
In all patients who received EDAS, good postoperative neovascularization was significant in those with a young age, MMD, without hypertension, and large bone flap size. No hypertension and large bone flap size were meaningful factors in the MMD group. AUROC showed that an appropriate bone flap size was 47.91 cm2. However, a further controlled prospective study is needed.

Indirect bypass surgery is an effective treatment for moyamoya disease (MMD), but the success of the surgery depends on the formation of spontaneous collateral vessels, which cannot be accurately predicted before surgery. Developing a prediction nomogram model for neoangiogenesis in patients after indirect revascularization surgery can aid surgeons in identifying suitable candidates for indirect revascularization surgery. This retrospective observational study enrolled patients with MMD who underwent indirect bypass surgery from a multicenter cohort between December 2010 and December 2018. Data including potential clinical and radiological predictors were obtained from hospital records. A nomogram was generated based on a multivariate logistic regression analysis identifying potential predictors of good neoangiogenesis. A total of 263 hemispheres of 241 patients (mean ± SD age 24.38 ± 15.78 years, range 1-61 years) were reviewed, including 168 (63.9%) hemispheres with good postoperative collateral formation and 95 (36.1%) with poor postoperative collateral formation. Based on multivariate analysis, a nomogram was formulated incorporating four predictors, including age at operation, abundance of ICA moyamoya vessels, onset type, and Suzuki stage. The C-index for this nomogram was 0.80. Calibration curve and decision-making analysis validated the fitness and clinical application value of this nomogram. The nomogram developed in this study exhibits high accuracy in predicting good neoangiogenesis after indirect revascularization surgery in MMD patients. This model can be very helpful for clinicians when making decisions about surgical strategies for MMD patients in clinical practice.

BACKGROUND: Moyamoya vasculopathy is a rare steno-occlusive cerebrovascular disorder presenting with ischemia or hemorrhage. There are racial and geographic differences in presentation and outcome. There is little information regarding moyamoya in Australia.
METHODS: Moyamoya patients undergoing surgery from 2001 to 2022 were studied retrospectively. The outcomes of revascularization surgery in adult and pediatric patients, with ischemic and hemorrhagic disease were analyzed, including functional outcomes, postoperative complications, bypass patency, and long-term rates of ischemic and hemorrhagic events.
RESULTS: A total of 68 patients with 122 revascularized hemispheres and 8 posterior circulation revascularizations were included in this study. Eighteen patients were of Asian descent and 46 were of Caucasian origin. Presentation was with ischemia in 124 hemispheres and hemorrhage in six hemispheres. There were 92 direct, 34 indirect, and 4 combined revascularization surgeries performed. Early postoperative complications occurred in 3.1% (n = 4) of operations and delayed complications (infection, subdural hematoma) occurred after 4.6% (n = 6) of operations. Mean follow-up was 6.5 years (3-252 months). There was 100% patency of direct grafts at last follow-up. There were no hemorrhagic events following surgery and 1 new ischemic event 2 years after surgery. There was significant improvement in physical health functional outcomes at most recent follow-up (P < 0.05); mental health outcomes were not different between preoperative and postoperative assessments.
CONCLUSIONS: The majority of Australian moyamoya patients are Caucasian and the most common clinical presentation is ischemia. Revascularization surgery had excellent outcomes with very low rates of ischemia and hemorrhage, comparing favorably to the natural history of moyamoya vasculopathy.

Moyamoya disease (MMD) is a rare steno-occlusive disease of the bilateral internal carotid arteries that predominantly occurs in East Asia. Since the first description of the MMD by Suzuki and Takaku in 1969, significant advances have been made in both basic and clinical understanding of the disease. The incidence and prevalence of pediatric MMD have increased, potentially due to improved detection rates. The advancement of neuroimaging techniques has enabled MRI-based diagnostics and detailed visualization of the vessel wall. Various methods of surgical treatments are successful in pediatric MMD patients, and recent studies emphasize the importance of reducing postoperative complications since the goal of MMD surgery is to prevent future cerebral infarction and hemorrhage. Long-term outcomes following appropriate surgical treatment in pediatric MMD patients have shown promising results, including favorable outcomes in very young patients. Further studies with a large patient cohort are needed to establish individualized risk group stratification for determining the optimal timing of surgical treatment and to conduct multidisciplinary outcome assessments.

A combined surgery of direct and indirect revascularization has been frequently performed in patients with moyamoya disease, though the efficacy of indirect revascularization surgery in adult patients with moyamoya disease has not been established. This study aimed to evaluate superficial temporal artery (STA) and deep temporal artery (DTA) diameters 1 day and 3 months after combined revascularization surgery in patients with moyamoya disease. We also investigated clinical factors related to DTA enlargement after surgery.
We examined 78 cerebral hemispheres in 57 adult and pediatric patients with moyamoya disease who underwent combined revascularization surgery [STA-MCA bypass and encephalo-duro-myo-synangiosis] in our institution. STA and DTA diameters were measured on axial magnetic resonance angiography images at 1 day and 3 months after surgery.
DTA diameter increased in 64 hemispheres (82.1%). DTA diameter increase in association with STA diameter decrease was found in 39 hemispheres (50%). The proportion of hemispheres with a reduction in STA diameter was significantly higher in hemispheres with DTA enlargement than in hemispheres with DTA reduction (P = 0.0088). Among the 64 hemispheres with DTA enlargement, 51 (79.7%) showed cerebrovascular reserve (CVR) impairment in the anterior cerebral artery (ACA) territory before surgery. CVR impairment in the ACA territory was the only clinical factor related to DTA enlargement (P < 0.001).
The DTA frequently enlarges after combined revascularization surgery, even in adult patients with moyamoya disease. In patients with impaired CVR in the ACA territory, blood supply from the DTA to the ACA territory can be expected after combined revascularization surgery.

Moyamoya disease may present with either hemorrhagic or ischemic strokes. Surgical bypass has previously demonstrated superiority when compared to natural history and medical treatment alone. The best bypass option (direct vs. indirect), however, remains controversial in regard to adult ischemic symptomatic moyamoya disease. Multiple studies have demonstrated clinical as well as angiographic effectiveness of direct bypass in adult hemorrhagic moyamoya disease. In particular, there are limited data regarding strategies in the setting of failed indirect bypass with recurrent hemorrhagic strokes. Here, we describe a salvage procedure.
We describe a case of a 52-year-old man who presented with hemorrhagic moyamoya disease and failed previous bilateral encephaloduroarteriosynangiosis (EDAS) procedures at an outside institution. On a 3-year follow-up diagnostic cerebral angiogram, no synangiosis was noted on the right side and only minimal synangiosis was present on the left. The left hemisphere was significant for a left parietal hypoperfusion state. We performed a salvage left proximal superficial temporal artery to distal parietal M4 middle cerebral artery bypass using the descending branch of the lateral circumflex artery as an interposition graft with preservation of the existing EDAS sites.
The patient underwent the procedure successfully and recovered well with resolution of headaches and no further strokes or hemorrhages on the 1-year follow-up magnetic resonance imaging of the brain.
This case presents the use of a salvage direct bypass technique for recurrent symptomatic hemorrhagic moyamoya disease after failed EDAS. The strategy, approach, and technical nuances of this unique case have implications for revascularization options.