Posterior cerebral territory ischemia in pediatric moyamoya: Surgical techniques and long-term clinical and radiographic outcomes

PURPOSE

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.

Analysis of Factors Affecting Good Neovascularization After Indirect Bypass Surgery: A Two-center Retrospective Study

OBJECTIVE

The purpose of this study was to analyze factors affecting good neovascularization after indirect bypass surgery.

METHODS

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).

RESULTS

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.

CONCLUSIONS

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.

Technical evolution of pediatric neurosurgery: moyamoya disease

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.

Revascularization Surgery for Moyamoya Vasculopathy: An Australian Experience

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.

Nomogram to Predict Good Neoangiogenesis After Indirect Revascularization Surgery in Patients with Moyamoya Disease: a Case-control Study

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.

Cerebrovascular Reserve Impairment in the Anterior Cerebral Artery Territory Predicts Deep Temporal Artery Enlargement After Combined Revascularization Surgery in Moyamoya Disease

OBJECTIVE

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.

METHODS

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.

RESULTS

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).

CONCLUSION

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.

The neurosurgical management of Severe Hemophilia A and Moyamoya (SHAM): challenges, strategies, and literature review

INTRODUCTION

Severe Hemophilia A and Moyamoya arteriopathy (SHAM syndrome) is a rare genetic disorder caused by deletion of portions of the cytogenic band Xq28. A case of SHAM syndrome requiring bilateral cerebral revascularization is described with an emphasis on perioperative management.

CASE REPORT

A 5-year-old boy with severe hemophilia A complicated by factor VIII inhibition presented with right-sided weakness. Imaging revealed multiple strokes and vascular changes consistent with Moyamoya disease. The patient underwent two-staged indirect cerebral bypass revascularizations, first on the left side and several months later on the right. Perioperative management required balancing the administration of agents to prevent coagulopathy and perioperative hemorrhage while mitigating the risk of thromboembolic events associated with bypass surgery. Despite a multidisciplinary effort by the neurosurgery, hematology, critical care, and anesthesiology teams, the post-operative course after both surgeries was complicated by stroke. Fortunately, the patient recovered rapidly to his preoperative functional baseline.

CONCLUSION

We describe a rare case of SHAM syndrome in a pediatric patient who required bilateral revascularizations and discuss strategies for managing the perioperative risk of hemorrhage and stroke. We also review existing literature on SHAM syndrome.

Postoperative neovascularization, cerebral hemodynamics, and clinical prognosis between combined and indirect bypass revascularization procedures in hemorrhagic moyamoya disease

OBJECTIVE

We evaluated what few studies emphasized the postoperative collateral formation and cerebral hemodynamics of hemorrhagic moyamoya disease (MMD).

METHODS

Hemorrhagic MMD patients treated surgically were retrospectively collected and dichotomized into combined bypass (CB) and indirect bypass (IB) groups. CB used superficial temporal artery-to-middle cerebral artery anastomosis combined with encephaloduroarteriomyosynangiosis (STA-MCA+EDAMS), and IB used encephaloduroarteriomyosynangiosis (EDAMS) for revascularization. Postoperative complications and clinical prognosis, as well as pre- and post-operative Modified Rankin Scale (mRS), collateral circulation status, and cerebral hemodynamics were observed and compared between the CB and IB groups.

RESULTS

A total of 37 patients with hemorrhagic MMD were identified. Of the 68 cerebral hemispheres, 47(69.1%) were combined revascularization, and the rest were indirect. During an average follow-up of 16.5 ± 8.7 months, the recurrent stroke events were significantly lower, as well as having a postoperative mRS scores≤ 2. A satisfactory postoperative collateral formation, and an improved dilation or extension of the anterior choroidal/posterior communication artery (AchA/PcoA) were significantly higher in the CB group than in the IB group (all P < .05). Compared with preoperative cerebral hemodynamics, relative cerebral blood flow (rCBF), relative cerebral blood volume (rCBV), mean transit time (MTT), and relative time to peak (rTTP) in the CB group; rCBF, rCBV, and MTT in the IB group were significantly improved (all P < .001). The CB group's postoperative rCBF was significantly improved compared with the IB group (P < .001).

CONCLUSIONS

STA-MCA bypass combined with EDAMS can obtain better postoperative collateral formation, cerebral hemodynamics, and clinical prognosis than EDAMS alone.

Occipital to Angular Artery Bypass for Post-irradiation Ischemia: 3-Dimensional Operative Video

The authors present a 3D surgical video of a direct occipital to angular artery bypass for cerebral revascularization in the setting of Post-irradiation middle cerebral artery stenosis and symptomatic hypoperfusion. The case refers to a 50-yr-old woman with a history of an unresectable residual skull base meningioma, previously approached through a left frontotemporal craniotomy, and treated with radiation 5 yr prior to presentation. She now presented with right-sided limb shaking transient ischemic attacks and aphasia, along with evidence of left middle cerebral artery territory ischemia. Her symptoms were progressive, despite extensive external carotid collateral blood supply through the prior craniotomy. The video analyzes the surgical steps of the procedure, emphasizing multiple surgical pearls. After positioning, an incision is designed to expose the full course of the occipital artery. After dissection of the donor vessel, a craniotomy is performed to expose the distal sylvian fissure. The donor and recipient vessels are prepared, and the anastomosis is performed with interrupted sutures given the sub-millimeter diameter of the recipient vessel (suture used: 10-0 Ethilon BV75-3 Taper, Ethicon, Johnson & Johnson). Every step of the closure is modified to avoid any constriction of the donor vessel. The patient tolerated the procedure well, and multiple modalities, both intra- and post operatively confirmed patency of, and robust flow within the bypass. No identifying patient information is included. However, the patient's consent was obtained for this publication.

Postoperative collateral formation after indirect bypass for hemorrhagic moyamoya disease

Background

The research on postoperative collateral formation for hemorrhagic moyamoya disease (MMD) evaluated by using digital subtraction angiography (DSA) is limited. Our study objective was to investigate the postoperative collateral formation after indirect bypass for hemorrhagic MMD.

Methods

All consecutive inpatients with hemorrhagic MMD who received indirect bypass at Beijing Tiantan Hospital, Capital Medical University from January 2010 through December 2018 were screened. The site of the hemorrhage was classified as either anterior or posterior. Postoperative collateral formation was evaluated on lateral views using the Matsushima scale. Univariate and multivariate logistic regression analyses were carried out to determine the factors influencing postoperative collateral formation.

Results

Six-four patients (64 hemispheres) were included in this study. After a median 8.5 months DSA follow-up, 14 (21.9%) hemispheres had grade A collateral circulation, 13 (20.3%) had grade B, and 37 (57.8%) had grade C. Twenty-seven (42.2%) hemispheres had good postoperative collateral formation and 37 (57.8%) had poor postoperative collateral formation. The univariate logistic regression analyses showed that age at operation (OR, 0.954; 95% CI, 0.908–1.003; p = 0.066), hemorrhagic site (OR, 4.694; 95% CI, 1.582–13.923; p = 0.005), and PCA involvement (OR, 3.474; 95% CI, 0.922–13.086; p = 0.066) may effect postoperative collateral formation. The multivariate logistic regression analyses showed that only anterior hemorrhage (OR, 5.222; 95% CI, 1.605–16.987; p = 0.006) was significantly related to good postoperative collateral formation.

Conclusion

Anterior hemorrhage was significantly related to good postoperative collateral formation after indirect bypass.

Sternocleidomastoid Encephalomyosynangiosis for Treatment-Resistant Moyamoya Disease

BACKGROUND AND IMPORTANCE

Refractory ischemic symptoms in moyamoya disease are a challenging problem, particularly in situations in which multiple direct and indirect revascularization techniques have already been employed. In addition, revascularization of the parietal lobes is difficult, as this area is a watershed between the middle cerebral artery and posterior cerebral artery distributions.

CLINICAL PRESENTATION

This is the case of a 50-yr-old woman with hemibody sensorimotor deficits, who had previously undergone bilateral arterial bypass and temporalis myosynangiosis. A method for indirect surgical cerebral revascularization is described, utilizing a rotated and tunneled sternocleidomastoid flap. The perfused muscle is approximated to the cortical surface, with adjacent sulci dissected to expose the underlying vasculature. After sternocleidomastoid encephalomyosynangiosis, the patient experienced symptomatic improvement, along with the appearance of new pial collateral vasculature on diagnostic cerebral angiography. Pre- and postoperative dynamic perfusion computed tomography with acetazolamide challenge demonstrate an increase in cerebral blood flow and decrease in mean transit time, as well as improved cerebrovascular reserve.

CONCLUSION

Sternocleidomastoid encephalomyosynangiosis using a tunneled muscle flap is a useful method for revascularization of the parietal and occipital lobes, particularly for refractory moyamoya in cases where a variety of other options have been exhausted.

Strategies for and Outcome of Repeat Revascularization Surgery for Moyamoya Disease: An American Institutional Series

BACKGROUND

Revascularization for moyamoya disease (MMD) effectively prevents future ischemic events. However, small subsets of patients with persistent or new symptoms due to inadequate collateralization require repeat revascularizations.

OBJECTIVE

To investigate the clinical and radiological outcome of repeat revascularization in MMD patients with previous indirect or direct bypasses.

METHODS

Single institution, retrospective analysis of a prospective MMD database.

RESULTS

From 1991 to 2014, this institution performed 1244 revascularization bypasses (1107 direct, 137 indirect) in 765 patients, of whom 57 were repeat revascularizations (38 indirect, 19 direct bypass). When initially performed at the institution, the repeat revascularization rate was 4% for indirect and 1% for direct bypasses (P = .03). Cohorts with previous indirect vs direct bypass were slightly younger (mean age 23 vs 30 yr), with fewer females (61% vs 84%, P = .08), and a similar mean duration between initial bypass and repeat revascularization (49 vs 47 mo). Both groups had similar repeat revascularization due to transient ischemic attacks (66% vs 63%). One acute graft occlusion in the previous direct bypass group was revised within 1 wk postoperatively. Over 50% of the repeat revascularizations in both groups were direct bypasses; the major difference being that the repeat bypass in the direct group was to augment another vascular territory. At nearly 5 yr mean follow-up, over 80% of patients in both groups are well, free from stroke/transient ischemic attack symptoms, with excellent radiological results.

CONCLUSION

Repeat revascularization can safely and effectively prevent future ischemic events. Indirect bypass has a higher rate of repeat revascularization than direct bypass.

Surgical Resection and Histopathological Analysis of a Thrombosed Giant Fusiform MCA Aneurysm After Initial Treatment with a Flow Diversion Construct

BACKGROUND

We describe the histopathology of an unruptured giant calcified left middle cerebral artery (MCA) fusiform aneurysm initially treated with endovascular flow diversion. The flow diversion construct underwent postoperative in-stent thrombosis, necessitating surgical resection of the aneurysm to eliminate mass effect.

METHODS

A 75-year-old woman with a known left MCA aneurysm presented to the emergency department with moderate right hemibody weakness. Owing to the clinical and radiographic progression of the aneurysm, the patient was offered treatment. She was initially offered open surgical management of the lesion but declined it, indicating that she would consider only endovascular treatment. The patient underwent endovascular reconstruction of the aneurysmal segment with an overlapping pipeline construct. Postoperatively, the patient experienced in-stent thrombosis of the pipeline construct. The thrombosed aneurysm exerted a progressive local mass effect, necessitating en bloc surgical resection of the aneurysm and stent construct. The aneurysm was submitted for pathological analysis, which demonstrated chronologically older thrombus outside the flow diversion construct.

RESULTS

Postsurgical imaging demonstrated a left MCA territory stroke. The patient gradually gained strength in her right hemibody. The histopathological analysis indicated that the degrees of platelet activation and clot formation in this case were dependent on the aggregate surface area of the thrombus and surface area of the pipeline device used in the reconstruction.

CONCLUSIONS

This technical report with histopathological analysis provides useful insight into the mechanism of aneurysmal thrombosis after flow diversion. It also raises new questions regarding the roles of thrombus formation, platelet aggregation, and stent construct surface area in the maintenance of vessel patency.

Early and noninvasive evaluation using superficial temporal artery duplex ultrasonography after indirect bypass for adult ischemic moyamoya disease

BACKGROUND

The validity of indirect bypass for adult patients with moyamoya disease is still debatable. Some patients are poor responders to indirect bypass, and additive intervention is occasionally required in these cases. Therefore, it is necessary to evaluate the development of collateral circulation as early as possible postoperatively.

METHODS

Fifteen adult patients (>17 years old) with moyamoya disease (22 affected sides) who underwent encephalo-duro-arterio-synangiosis (EDAS) at Fukuoka University Hospital from April 2008 to August 2014 were included. All patients had ischemic symptoms of at least one hemisphere. Superficial temporal artery duplex ultrasonography (STDU) was performed before and 3, 6, and 12 months postoperatively. Digital subtraction angiography was performed 1 year after the operation to evaluate the development of collateral circulation. Hemispheres exhibiting collateral formation of more than one-third of the MCA distribution were defined as good responders, and those with less than one-third were defined as poor responders.

RESULTS

EDAS induced the formation of well-developed collaterals in 17 of 22 affected sides (77.3%) of adult patients with ischemic moyamoya disease. Regardless of the degree of collateral formation, the ischemic event subsided eventually with time in all patients. In good responders, the pulsatility index obtained by STDU showed a drastic decrease 3 months after the operation, while it did not change significantly in poor responders. Absence of this decrease in the pulsatility index along with no change in the flow velocity reliably indicated poor responders.

CONCLUSIONS

Neovascularization after EDAS can be evaluated noninvasively in early phase using STDU.