Semi-autonomous Robot for Diagnostic Colonoscopy

C R Welch, BS¹, H Dehghani, MS¹, Benjamin Terry, PhD¹, Carl Nelson, PhD¹, Tammy Kindel, MD, PhD², Dmitry Oleynikov, MD². ¹University of Nebraska Lincoln, ²University of Nebraska Medical Center

INTRODUCTION: Diagnostic colonoscopy (DC) is recommended for all adults at the age of 50 for initial colon cancer screening. However, there is an ongoing hesitancy within the general public to undergo DC due to concerns of procedural pain and discomfort. Thus, there are efforts in the biomedical community to explore new ways to advance an endoscope through the colon so that patients experience less pain and discomfort during DC with hopes to increase colorectal cancer screening compliance. Therefore, we designed and tested a semi-autonomous robot for DC to increase patient comfort, and decrease procedural times.

METHODS AND PROCEDURES: The following criteria were used to design the robot: (1) easily fits inside an insufflated colon, (2) follows the natural path of the colon and does not generate intraluminal loops, (3) the force on the robotic head can be easily observed to avoid colon perforation, (4) advance to the cecum (150 cm) in under 10 minutes, and (5) mechanical and electrical components present no risk of excessive heating or friction on the colon walls.

After successful robot design the model was tested for robot mobility through an acrylic tube and synthetic colon in straight paths, a U-shaped path, and a sharp path of 180 degrees (Figure). Finally, the robot was tested ex-vivo in a porcine colon in the same configurations.

RESULTS: We created a robot which uses air and a long, rolled-up latex tube to advance the endoscopic device. As air is pumped into the system, the coiled, latex tube inside the robot head unravels and advances the device. The propelling point was maintained directly behind the head at all times, greatly reducing the risk of loop formation within the colon.

The device fits easily inside an insufflated porcine colon. There is no risk of excessive heating or friction to the colon walls based on mechanical and electrical analysis, and no colon wall perforations were experienced. The current prototype can advance 80 cm through a porcine colon, including passing one 90-degree turn unaided, and two consecutive 90-degree turns by manually assisting the robot head direction.

CONCLUSIONS: This study describes successful proof-of-concept development of a semi-autonomous robot for DC which provides the benefits of minimal loop formation, quick advancement, simplistic use and safe tissue interface. Further design modifications are in progress to improve colonic travel distance.

Figure: Experiment (A) through an acrylic tube (B) in synthetic colon in U-shape (C) through a sharp 180° path.