Complications Associated with Combined Direct and Indirect Bypass in Moyamoya Disease: A Meta-analysis and Consideration in Pediatric Patients

Introduction: Cerebral revascularization surgery is a common procedure performed to help reverse or prevent ischemic episodes and reduce hemorrhage risk in Moyamoya Disease (MMD). Revascularization strategies include direct, indirect, or combined direct and indirect (CB). The course of MMD after intervention is not clearly elucidated, especially with consideration to pediatrics. Our aim is to conduct a review on the complications associated with the CB bypass technique in MMD treatment and analyze differences between the adult and pediatric population.

Methods: A systematic review of the literature was conducted in accordance with the PRISMA guidelines. Databases, including PUBMED, Cochrane Library, Web of Science, and CINAHL, were queried from January 1980 to March 2022. Complications were defined as any adverse clinical events occurring within 3 months after MMD revascularization surgery. Adults were defined as age >/= 16 years of age as this was the most commonly reported age discriminator in the included studies.

Results: Of 1580 articles reviewed, 19 were included in the final analysis. A total of 980 patients underwent combined revascularization, with 167 (17%) undergoing surgery on both hemispheres. The range of period for follow-up was 3 months to 9 years, with 19 (100%) of studies having a greater than 3 months of minimum follow-up and 17 (89.5%) having greater than 6 months of minimum follow-up. For the adult and pediatric population, ischemic events were the most present (8.7% and 12%, respectively), followed by hemorrhagic events (5% and 0.9%), and lastly, seizure events (3.2% and 0.4%). In mixed age range studies, ischemic and hemorrhagic complications presented the same percentage of occurrence (1.8%), followed by seizure events (0.2%).

Conclusion : Ischemic events are the most common complication in CB for MMD. In comparison with adult population, pediatric patients submitted to CB had a smaller proportion of hemorrhagic events and a greater proportion of ischemic events.