Surgical Revascularization for Children with Moyamoya Disease: A New Modification to the Pial Synangiosis

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.

Immediate Postoperative Electroencephalography Monitoring in Pediatric Moyamoya Disease and Syndrome

BACKGROUND

Moyamoya disease and syndrome are progressive steno-occlusive cerebrovascular diseases that manifest clinically with ischemic episodes. There is evidence for the use of electroencephalography (EEG) in preoperative and long-term postoperative evaluation of these patients, as well as in the intraoperative period to monitor for changes correlated with perioperative ischemic events. However, the utility of EEG in the immediate postprocedure time period has not previously been described.

METHODS

We review six patients who underwent pial synangiosis from 2017 to 2019. EEGs from the preoperative, intraoperative, and immediate postoperative period were evaluated, as well as clinical examination changes and subsequent interventions.

RESULTS

Six patients with postoperative EEG monitoring following pial synangiosis were included. EEG data was collected preoperatively, intraoperatively, and continuously postoperatively. Preoperatively, five of six patients had normal background activity on EEG, whereas one of six had hemispheric asymmetry. Three patients had new or worsening hemispheric intracerebral asymmetry on EEG during the immediate postsurgical period. Two of these had no clinical manifestations of ischemia, and one had transient left facial weakness. All three underwent blood pressure augmentation with improvement in the asymmetry on EEG and clinical improvement in the symptomatic patient.

CONCLUSIONS

Although widely accepted as a useful tool during the preoperative and intraoperative periods of evaluation and management of moyamoya disease and syndrome, we propose that the use of continuous EEG in the immediate postoperative period may have potential as a useful adjunct by both detecting early clinical and subclinical intracranial ischemia.

The trend of indirect anastomosis formation in a 2-vessel occlusion plus encephalo-myo-synangiosis rat model

Background

Basic research on the factors influencing indirect anastomosis formation in a 2-vessel occlusion plus encephalo-myo-synangiosis (2VO + EMS) rat model is conducive to improving the efficacy of indirect revascularization surgery in the clinic. However, the time point at which anastomosis between the rat temporal muscle (TM) and brain naturally has the greatest effect after encephalo-myo-synangiosis (EMS) remains unknown. Therefore, we conducted this study to explore the peak time of indirect anastomosis formation in the 2VO + EMS rat model.

Methods

Forty 2VO + EMS rats were randomly divided into five groups (n=8) according to the length of time (by week) after EMS, and 2VO rats were used as the control group (n=8). The expression of vascular endothelial growth factor (VEGF) and CD31 on the EMS side of the brain, perfusion ratio [improvement of cerebral blood perfusion (CBP) on the EMS side] and Morris water maze (MWM) results were compared between groups. Furthermore, the trends of the above variables were explored over weeks.

Results

Overall, the expression of VEGF and CD31, the perfusion ratio and the cognitive improvement in the 2VO + EMS rat model gradually increased over weeks after EMS. The VEGF and CD31 expression (as detected by immunofluorescence), perfusion ratio and number of times crossing the platform area peaked at 4 weeks after EMS. In addition, both the escape latency and the time spent in the target quadrant peaked in the fifth week after EMS.

Conclusions

After establishing the 2VO + EMS rat model, the degree of endothelial cell (EC) proliferation and CBP improvement on the EMS side of the brain peaked at 4 weeks after EMS, whereas the cognitive improvement peaked in the fifth week.

Increasing the expression of microRNA-126-5p in the temporal muscle can promote angiogenesis in the chronically ischemic brains of rats subjected to two-vessel occlusion plus encephalo-myo-synangiosis

BACKGROUND

miR-126-5p plays an important role in promoting endothelial cell (EC) proliferation. We thus explored whether miR-126-5p can promote EC proliferation and angiogenesis in chronically ischemic brains (CIBs).

RESULTS

Improved revascularization in moyamoya patients was correlated with upregulated miR-126-5p expression in the TM and DM. In vitro experiments showed that miR-126-5p promoted EC proliferation through the PI3K/Akt pathway. CIBs from the agomir group exhibited significantly higher p-Akt, VEGF, CD31 and eNOS expression compared with the control CIBs. The ICBP and the RCF were significantly better in the agomir compared with the control group.

CONCLUSION

Increasing miR-126-5p expression in the TM can promote EC proliferation and angiogenesis in CIBs of 2VO+EMS rats through the PI3K/Akt pathway.

METHODS

We assessed the correlation between revascularization and miR-126-5p expression in the temporal muscle (TM) and dura mater (DM) of moyamoya patients. The effect of miR-126-5p on EC proliferation and downstream signaling pathways was explored in vitro. We established an animal model of two-vessel occlusion plus encephalo-myo-synangiosis (2VO+EMS), transfected the TM with miR-126-5p agomir/antagomir, compared the expression of miR-126-5p and relevant downstream cytokines in brain tissue among different groups, and investigated the improvement in cerebral blood perfusion (ICBP) and the recovery of cognitive function (RCF).