Advancing Evidence Quality and Reproducibility in Bypass in Neurosurgery Research: A Systematic Review and Reporting...

Bypass surgery is an important option for treating complex intracranial aneurysms (IAs) and Moyamoya disease (MMD), particularly when conventional approaches are insufficient. However, the literature remains heterogeneous, with important limitations in reporting quality that hinder reproducibility and comparability. We aimed to evaluate the current evidence and propose a reporting guideline to improve transparency and methodological rigor.

We searched PubMed, Embase, and Web of Science databases. Eligible studies were observational or randomized studies reporting clinical and/or surgical outcomes of bypass for IAs or MMD, including a sample size of ≥3 patients, and published in English between January 1, 2000, and January 1, 2025. Assessment focused on key domains: (1) Assessment of reported baseline characteristics; (2) assessment and reporting on imaging methods and pathology characteristics; (3) reporting on pivotal concept definitions; (4) reporting on neurosurgeon(s) and staff characteristics; (5) reporting on the anesthetic protocol; (6) reporting on vascular procedure details; (7) reporting on antiaggregant and anticoagulation protocol; (8) assessing and reporting on clinical and surgical outcomes, besides adverse events; (9) reporting on retreatment details; and (10) funding and conflicts of interest declarations.

Thirty studies were included. Our assessment revealed substantial reporting gaps across all domains pertinent to bypass. A bypass reporting guideline was developed and organized into 10 domains, featuring a pragmatic checklist composed of one common domain and disease-specific sections for IA and MMD. The guideline emphasizes detailed technical reporting, graft patency assessment and verification, perioperative antithrombotic management, and standardized clinical and radiological outcome measures.

This systematic review on bypass surgery for IA and MMD identified substantial methodological and reporting limitations that compromise evidence quality and comparability. The proposed reporting guideline provides a structured framework to address these gaps, enhancing transparency, reproducibility, and standardization, with the potential to strengthen the evidence base and improve patient care.