# Efficacy of intraoperative indocyanine green videoangiography (ICG-VA) and FLOW 800 in the surgical management of intracranial aneurysms: a systematic review and meta-analysis

## TL;DR

This study reviews how combining ICG-VA and FLOW 800 improves detection of surgical issues during aneurysm clipping, but more research is needed to confirm its effectiveness.

## Contribution

The study introduces a meta-analysis evaluating the combined use of ICG-VA and FLOW 800 for intraoperative aneurysm surgery outcomes.

## Key findings

- Combined ICG-VA and FLOW 800 detected misclipping in 9.36% of cases.
- Aneurysm remnants were identified in 6.55% of cases using the combined tools.
- Retrospective studies showed higher detection rates than prospective ones.

## Abstract

Intraoperative assessment of aneurysm clipping remains technically challenging, particularly in identifying misclippings, aneurysmal remnants, and vessel compromise. Indocyanine green videoangiography (ICG-VA) provides real-time visualization but lacks hemodynamic quantification. FLOW 800 is a semi quantitative analysis tool that enhances blood flow evaluation. This meta-analysis aims to evaluate the combined diagnostic efficacy of ICG-VA and FLOW 800 in intracranial aneurysm surgery, focusing on intraoperative outcomes.

A systematic review was conducted in five databases (PubMed, Embase, Scopus, Web of Science, CENTRAL). The protocol was registered in PROSPERO (CRD420251014600). Twelve studies were included in the qualitative synthesis (344 aneurysms), of which eight contributed quantitative data to the meta-analysis (277 aneurysms). Pooled proportions of misclipping, aneurysmal remnant, vascular stenosis/occlusion, and clip repositioning were calculated using a random-effects model. Subgroup analyses, meta-regression, leave-one-out sensitivity analysis, and assessment of publication bias (funnel plot) were performed. Risk of bias was assessed using the QUADAS-2 tool.

The pooled intraoperative detection rates using ICG-VA and FLOW 800 were: misclipping 9.36% (95% CI: 4.75–17.64), aneurysm remnant 6.55% (95% CI: 3.29–12.65), vessel stenosis or occlusion 6.90% (95% CI: 3.28–13.96), and clip repositioning 8.13% (95% CI: 4.05–15.63). Retrospective studies showed higher detection rates than prospective ones. Meta-regression identified study design as a significant predictor for all outcomes (p < 0.0001), while older patient age was associated with increased remnant detection (p = 0.0247) and clip repositioning (p = 0.0073). Funnel plots revealed slight asymmetry, and GRADE evaluation indicated moderate certainty for misclipping and clip repositioning, and low certainty for remnants and stenosis.

The combined use of ICG-VA and FLOW 800 enhances the intraoperative detection of misclipping, residual aneurysm, and flow disturbances not evident with ICG-VA alone. These findings support its role as a complementary intraoperative tool. However, due to limited validation against angiographic standards, it should not replace DSA. Further prospective studies are warranted to confirm its clinical utility and encourage broader adoption in neurosurgical practice.

The online version contains supplementary material available at 10.1007/s00701-026-06779-6.