Project Summary/Abstract The objective of this proposal is to create dexterous steerable instrument sheaths that enable patients who currently are subject to invasive surgeries to receive minimally invasive endoscopic interventions. Clinical significance comes from (1) the high incidence of colon lesions – there are 6.3 million colonoscopies per year with 50% finding lesions, and (2) the difficulty of removing a subset of these (those with challenging sizes, shapes, or locations) due to the limited dexterity of conventional endoscopes. This results in over 60,000 patients per year in the USA with colon lesions that the very best endoscopists have demonstrated can be safely removed with an outpatient endoscopic procedure, who are instead subjected to invasive surgery to remove a section of their colon (i.e. colectomy surgery). This occurs because of the dexterity gap between the best endoscopists and typical endoscopists. We aim to close this gap with the new device described in this proposal. The innovation in our work is a new steerable sheath concept that harnesses elastic asymmetry to provide dexterity at the tip of a colonoscope. This dexterity reduces the difficulty of removing challenging lesions endo- scopically. Our controllably deflectable, thin-walled, tube-like device will be small enough to pass through the port of a conventional endoscope, while providing a large open lumen for surgical instruments to pass through. Its innovative mechanical design accomplishes this by dispensing with conventional pull-wires, hinges, and other bulky force transmission elements in favor of the push-pull interaction of two thin-walled tubes, which bend con- trollably via interacting regions of stiffness asymmetry at their tips. Our approach consists of three Specific Aims. Aim 1 addresses the construction of the steerable sheaths and their actuation systems. Aim 2 focuses on enabling dexterous physician control via a physician interface console, and optimization of device dexterity. Aim 3 consists of ex vivo and in vivo porcine experiments to demonstrate that the device enables physicians new to endoscopic dissection to perform with accuracy and efficiency similar to what elite endoscopists have shown can effectively and safely treat the 60,000 patients mentioned above. The endpoint of this project will be a device that has been validated in an animal model, setting the stage for rapid clinical translation after successful completion of this R01.

Narrative/Public Health Impact Despite the fact that safe and effective endoscopic procedures for removal of colon lesions have been demon- strated in the academic literature, over 60,000 patients per year in the USA alone still undergo invasive surgery to remove sections of their colons. The culprit for this is the lack of dexterity in tools passed through conventional colonoscopes, making procedures so challenging that only a small number of the best endoscopists can attempt them. To help more patients benefit from minimally invasive, endoscopic approaches, we propose a new dex- terous steerable instrument sheath that is thin enough to fit through the port of a conventional colonoscope and provides dexterity, enabling endoscopists to perform complex surgical motions easily inside a patient's colon.