Mechanical auxiliary devices to expose mucosal surface in colonoscopy

Colonoscopy is a cornerstone of colorectal cancer (CRC) prevention, with adenoma detection rate (ADR) serving as a critical quality metric. However, substantial variability in ADR persists across operators, and a significant proportion of colorectal neoplasia-particularly flat, serrated, and right-sided lesions-continues to be missed. These limitations are often attributable to suboptimal mucosal exposure, especially in anatomical regions hidden behind haustral folds and flexures. To address this, a variety of mechanical auxiliary devices-collectively termed behind-folds visualizing techniques and technologies (BFTs)-have been developed to enhance mucosal exposure during withdrawal. These include both add-on devices (e.g., caps, Endocuff, EndoRings) and integrated technologies (e.g., G-EYE, FUSE, Third Eye), each with varying levels of evidence and practicality. This review critically appraises current data on BFTs, highlighting their efficacy in improving ADR, particularly among endoscopists with lower baseline performance. Meta-analyses suggest that simple, low-cost devices such as Endocuff and caps offer the most favorable balance of effectiveness, accessibility, and ease of use. Furthermore, emerging data indicate that combining mechanical exposure devices with artificial intelligence-based systems may yield additive benefits. BFTs represent pragmatic tools to optimize colonoscopy quality and reduce post-colonoscopy CRC. Their selective implementation-especially in low-performing settings-should be considered a key component of modern endoscopic practice.