Development of structured fabric-based endoscopic guiding sheath with tunable diameter and stiffness functions

Flexible surgical instruments with multiple degrees of freedom or continuum surgical instruments demonstrate significant advantages in Natural Orifice Transluminal Endoscopic Surgery (NOTES), particularly when navigating the complex anatomical pathways of the human gastrointestinal tract. However, conventional endoscopic instruments with fixed diameters and stiffness profiles risk exerting excessive mechanical stress on esophageal tissues, with clinical studies documenting mucosal tears and hemorrhagic complications in up to 15% of transgastric cholecystectomy procedures. To address these limitations, we developed a structured fabric-based guiding sheath featuring dynamic diameter modulation and tunable stiffness. This structured fabric construct enables the creation of a stable internal channel (15 mm working diameter) while demonstrating remarkable radial expandability from 15 to 20 mm outer diameter. Through pneumatic control systems, the guiding sheath achieves a 7.3-fold increase in stiffness under negative pressure conditions (0-80 kPa), significantly enhancing endoscopic maneuverability while maintaining patient safety. Phantom experiments demonstrated that the structured fabric-based guiding sheath establishes a consistently internal channel (15 mm inner diameter) while maintaining radial stability, effectively securing the insertion of endoscopic instruments and showing its potential for enhancing the safety and efficiency of NOTES procedures.