Dual-Continuum Design Approach for Intuitive and Low-Cost Upper Gastrointestinal Endoscopy

Abstract

This paper introduces a methodology to design intuitive, low-cost, and portable devices for visual inspection of the upper gastrointestinal tract. Methods: The proposed approach mechanically couples a multi-backbone continuum structure, as the user interface, and a parallel bellows actuator, as the endoscopic tip. Analytical modeling techniques derived from continuum robotics were adopted to describe the endoscopic tip motion from user input, accounting for variations in component size and pneumatic compressibility. The modeling framework was used to improve intuitiveness of user-to-task mapping. This was assessed against a 1:1 target, while ease-of-use was validated using landmark identification tasks performed in a stomach simulator by one expert and ten non-expert users; benchmarked against conventional flexible endoscopy. Pre-clinical validation consisted of comparative trials in in-vivo porcine and human cadaver models. Results: Target mapping was achieved with an average error of 5 • in bending angle. Simulated endoscopies were performed by an expert user successfully, within a time comparable to conventional endoscopy (<1 minute difference). Non-experts using the proposed device achieved visualization of the stomach in a shorter time (9s faster on average) than with a conventional endoscope. The estimated cost is <10 USD and <30 USD for disposable and reusable parts, respectively. Significance and Conclusions: Flexible endoscopes are complex and expensive devices, actuated via non-intuitive cable-driven mechanisms. They frequently break, requiring costly repair, and necessitate a dedicated reprocessing facility to prevent cross contamination. The proposed solution is portable, inexpensive, and easy to use, thus lending itself to disposable use by personnel without formal training in flexible endoscopy.

Guidelines for Robotic Flexible Endoscopy at the Time of COVID-19

“…The Bellowscope is another promising device not included in the table since it is not strictly a robotic platform but is a low-cost disposable endoscope. Its working principle is based on pistons and bellow actuators which are controlled by multi-DOF handheld controller ( Garbin et al, 2018a ; Garbin et al, 2018b ; Garbin et al, 2019 ; Chandler et al, 2020 ).…”

A dual‐bending endoscope with shape‐lockable hydraulic actuation and water‐jet propulsion for gastrointestinal tract screening

“…A number of approaches to low‐cost endoscope design have been proposed; including cable driven, 9 tethered capsules 10,11 and pneumatically driven 12,13 devices. In addition to these, water‐jet driven endoscopes represent a prevalent approach, with the advantage of low‐cost and disposable features and water‐jet based orientation control 14–17 .…”

Parallel Helix Actuators for Soft Robotic Applications

“…Unfortunately, this adds significant procedural complexity that is amplified as the device scale is reduced. Generally, multi-chamber actuators employ three chambers distributed with their centers 120° apart (Suzumori et al, 1991a , b ; Benjamin et al, 2012 ; Cianchetti et al, 2013 ; Martinez et al, 2013 ; Yahya et al, 2014 ; Sun et al, 2016 ; Yan et al, 2016 ; Drotman et al, 2017 ; Nguyen et al, 2017 ; Robertson and Paik, 2017 ) and may be fabricated in a number of ways; for example: (i) molding with constant axial cross-sectional cores (Suzumori et al, 1997 ; Martinez et al, 2013 ; Yahya et al, 2014 ; Fu et al, 2020 ); (ii) assembly of pre-formed individual chambers (Cianchetti et al, 2013 ; Matteo et al, 2014 ; Ranzani et al, 2015 ; Nguyen et al, 2017 ; Garbin et al, 2018 , 2019 ; Peng et al, 2019 ); and (iii) 3D-printing of integrated designs (Peele et al, 2015 ; Wallin et al, 2018 ; Yirmibesoglu et al, 2018 ; Drotman et al, 2019 ). Although promising, these methods carry trade-offs between achievable internal chamber geometry, complexity, resilience of assembly, material selection, and practicable actuator scale and feature resolution (Schmitt et al, 2018 ).…”

“…Specific benefits associated with PHAs are (1) integrated multi-chamber designs scalable to small size (<1 cm diameter for three-chamber design); (2) the potential for single-step, single-material molding, reducing reliance on sealing and layer bonding, and avoiding the need for assembly; (3) simple “unscrewing” of mold cores to reduce the risk of damage to the internal features of the actuator during demolding; (4) design flexibility allowing adjustment to PHA geometry and scale for application specific optimization; and (5) 3D motion description through kinematic models based on the constant-curvature assumption. We envisage PHAs having utility in medical robotics for example in minimally invasive surgery (Abidi et al, 2018 ) or endoscopy (Garbin et al, 2019 ); or providing a generic actuator platform for soft robotic applications.…”