Stress Dispersion Design in Continuum Compliant Structure toward Multi-DOF Endoluminal Forceps

Abstract

Gastrointestinal cancer, when detected early, is treated by accessing the lesion through the natural orifice using flexible endoscopes. However, the limited degree-of-freedom (DOF) of conventional treatment devices and the narrow surgical view through the endoscope demand advanced techniques. In contrast, multi-DOF forceps systems are an excellent alternative; however, these systems often involve high fabrication costs because they require a large number of micro-parts. To solve this problem, we designed compact multi-DOF endoluminal forceps with a monolithic structure comprising compliant hinges. To allow an efficient stress dispersion at the base end when the hinge bends, we proposed a novel design method to obtain the hinge parameters using the beam of uniform strength theory. This method does not involve a high computational cost. The results show that the improved design with a variable hinge thickness can reduce the maximum bending stress, dispersing the stress in a larger area than that of the previous design considering a constant thickness of the hinge. Moreover, the experiments conducted in a prototype confirm that the radius of the curvature was significantly improved. The proposed method could aid in designing other continuum robots relying on compliant hinges.

Improvement in endoluminal procedures using versatile robot technology

“…Article (Osawa et al 2022) developed miniature multi-degree-of-freedom (DOF) endoluminal forceps with solid construction with flexible hinges.…”

Stereo Visual Servoing Control of a Soft Endoscope for Upper Gastrointestinal Endoscopic Submucosal Dissection

“…Currently, most ESD procedures are dependent on systems that utilize a single flexible arm outfitted with a monocular endoscope and various electrosurgical knives designed for specific surgical tasks [8]. However, due to the limited degrees of freedom (DoFs) of existing ESD endoscopes and the high skills required, improper operations during the procedure may lead to some complications such as tissue perforation and bleeding [9]. Additionally, the narrow visual field offered by traditional endoscopes hinders the surgeon's ability to perform precise, multi-angle excisions, emphasizing the necessity for an ESD system with improved visual capabilities and instrument control [10].…”

“…Micromachines 2024, 15, 276 2 of 22 required, improper operations during the procedure may lead to some complications such as tissue perforation and bleeding [9]. Additionally, the narrow visual field offered by traditional endoscopes hinders the surgeon's ability to perform precise, multi-angle excisions, emphasizing the necessity for an ESD system with improved visual capabilities and instrument control [10].…”