MorphGI: A Self-Propelling Soft Robotic Endoscope Through Morphing Shape

Colonoscopy is currently the best method for detecting bowel cancer, but fundamental design and construction have not changed significantly in decades. Conventional colonoscope (CC) is difficult to maneuver and can lead to pain with a risk of damaging the bowel due to its rigidity. We present the MorphGI, a robotic endoscope system that is self-propelling and made of soft material, thus easy to operate and inherently safe to patient. After verifying kinematic control of the distal bending segment, the system was evaluated in: a benchtop colon simulator, using multiple colon configurations; a colon simulator with force sensors; and surgically removed pig colon tissue. In the colon simulator, the MorphGI completed a colonoscopy in an average of 10.84 min. The MorphGI showed an average of 77% and 62% reduction in peak forces compared to a CC in high- and low-stiffness modes, respectively. Self-propulsion was demonstrated in the excised tissue test but not in the live pig test, due to anatomical differences between pig and human colons. This work demonstrates the core features of MorphGI.

Colonic displacement as a marker of endoscopic skill: development of a novel tool for endoscopy training

BACKGROUND

Colonoscopy is a technically challenging procedure. The colonoscope is prone to forming loops in the colon, which can lead patient discomfort and even perforation. We hypothesized that expert endoscopists use techniques to avoid loop formation, identify and straighten loops earlier, and thus exert less force.

METHODS

Using a commercially available physical colon simulator model (Kyoto Kagaku), electromagnetic tracking markers (NDI Medical) were placed along the mobile segments of the colon (sigmoid, transverse) to measure the degree of displacement of the colon as the scope was advanced to the cecum. The colon model was set for each participant to simulate a redundant alpha loop in the sigmoid colon. Gastroenterology and surgical trainees and attendings were assessed. Demographic data were collected for each participant.

RESULTS

Seventy-five participants were enrolled in the study. There were 17 (22.7%) attending physicians, and 58 (77.3%) trainees. Attending physicians advanced the scope to the cecum faster. The mean time required for procedure completion was 360.5 s compared to 178.4 s for the trainee and attending groups respectively (mean difference: 182.1 s, 95% CI: 93.0, 269.7; p = 0.0002). Attending physicians exerted significantly lower mean colonic displacement than trainees. The mean colonic displacement was 79.8 mm for the trainee group and 57.9 mm for the attending group (mean difference: 21.9 mm, 95% CI: 2.6, 41.2; p = 0.04). Those who used torque steering caused lower maximum colonic displacement than those who used knob steering.

CONCLUSION

Attending physicians advance the scope during colonoscopy in a manner that results in significantly less colonic displacement than resident trainees. Although prior studies have shown a difference in force application between endoscopists and inexperienced students, ours is the first to differentiate across varying degrees of endoscopic skill. Future studies will define metrics for incorporation into endoscopic training curricula, focusing on techniques that encourage safety and comfort for patients.