Off-campus UNL users: To download campus access dissertations, please use the following link to log into our proxy server with your NU ID and password. When you are done browsing please remember to return to this page and log out.

Non-UNL users: Please talk to your librarian about requesting this dissertation through interlibrary loan.

Automation of Surgical Procedures: Colonoscopy Locomotion and Laparoscopic Suturing

Hossein Dehghani Ashkezari, University of Nebraska - Lincoln

Abstract

Over the past decades, diagnostic and therapeutic procedures have improved public health. Colonoscopy, for example, is a screening procedure to diagnose and treat colorectal cancer. The conventional colonoscopy is an efficient way to prevent colorectal cancer; however, the uncomfortable nature of conventional colonoscopy discourages potential patients from compliance with recommended diagnostic guidelines. The overall goal of this work is to minimize the invasiveness of traditional colonoscopy. Our locomotion approach takes advantage of longitudinal expansion of a latex tube to propel the robot’s tip along the colon. In the preliminary ex-vivo experiments, the robot successfully advanced 1.5 meters inside an excised curvilinear porcine colon with average speed of 28 mm/sec, and was capable of traversing bends ranging from 30 to 90 degrees. The robot creates less than 6 N of normal force at its tip when it is pressurized to 90 kPa. This maximum force generates pressure of 44.17 mmHg at the tip, which is significantly lower than safe intraluminal human colonic pressure of 80 mmHg. The robot design inherently prevents loop formation in the colon, which is recognized as the main cause of post-procedural pain in patients. ^ Single-port laparoscopic (SPL) surgery is another recent advancement in medicine. SPL is performed through a single incision, offering greater benefit than traditional laparoscopy. Despite the potential advantages of SPL, it presents challenges for a surgeon, such as reduced workspace. In robotic single-port access surgeries, robot size is crucial due to the limited space. Thus, a robot may be designed to be underactuated. Suturing, in contrast, is a complicated task and requires full actuation. This study aims to overcome this shortcoming by implementing an optimization-based algorithm for autonomous suturing for an underactuated robot. The proposed algorithm approximates the ideal suturing trajectory by slightly reorienting the needle while minimizing the deviation of the needle with respect to ideal suturing. The deviation of the path taken by a custom robot with respect to the ideal trajectory varies depending on the suturing start location within the workspace as well as the needle size. The maximum deviation (dmax) was 9.8±6.45 mm and the values ranged from 3.86 (mm) to 29.26 (mm). The optimization-based algorithm maximized the accuracy of a four-DOF robot to perform a path-constrained trajectory.^

Subject Area

Biomedical engineering

Recommended Citation

Dehghani Ashkezari, Hossein, "Automation of Surgical Procedures: Colonoscopy Locomotion and Laparoscopic Suturing" (2017). ETD collection for University of Nebraska - Lincoln. AAI10607672.
http://digitalcommons.unl.edu/dissertations/AAI10607672

Share

COinS