A Soft Growing Robotic Endoscope for Painless and Strain-Free Insertion.

Abstract

Numerous studies have attempted to develop medical devices using vine robots due to their potential for frictionless locomotion and adaptability in confined environments. However, for applications in colonoscopy, challenges such as high stiffness, limited steering capabilities, difficulties in integrating tethered sensors, and issues related to safe retraction have hindered their practical application. This article addresses these challenges and presents a comprehensive solution that simultaneously resolves these issues while preserving the intrinsic features of vine robots. We propose a novel soft robotic endoscope that leverages an optimized eversion mechanism to maintain low stiffness and ensure compliance with the natural curvature of the colon, minimizing bowel distension. To enable real-time imaging, we introduce a passive tethered camera stabilization system that secures the camera at the distal tip with minimal internal tension. Additionally, the device integrates active steering capabilities using fabric pneumatic artificial muscles, allowing for precise two-degree-of-freedom steering to navigate through complex pathways. A non-sealed, self-retractable mechanism ensures safe and reliable retraction by preventing buckling while maintaining the robot's compliance, even with an embedded tethered sensor inside the inner channel. Comprehensive characterization of key parameters, such as vine diameter and retraction channel geometry, further enhances the system's performance in endoscopic applications. The effectiveness of the proposed endoscope was validated through extensive testing in endoscopic phantom models and in vivo trials, demonstrating significant reductions in insertion forces and colon deformation compared with conventional endoscopes. In phantom studies, the device demonstrated an 80% reduction in mesentery extension compared with a conventional flexible endoscope. In vivo, the soft growing endoscope (SGE) reached the ileocecal valve within 2 min while maintaining real-time imaging, internal channel integrity, and buckling-free retraction. By overcoming key challenges in adapting vine robots for endoscopy, this SGE offers a minimally invasive, safer, and more effective solution for colonoscopy, enhancing patient comfort and procedural efficiency while reducing physical strain on physicians.