New Kinematic Metric for Quantifying Surgical Skill for Flexible Instrument Manipulation

Colonoscopy is a minimally invasive endoscopic procedure to survey, diagnose and treat possible disease in the colon. Clinicians are trained to manipulate a colonoscope while minimizing the force exerted on the colon walls to reduce the danger of luminal perforation and discomfort to the patient. Here, we propose and evaluate a metric, called Global Isotropy Index (GII), to quantify the expertise of the clinician. The colonoscope is modeled as a continuum robot with multiple bending sections. The Jacobian operator, which relates the proximal forces applied by the clinician to the distal forces, provides a basis to compute the GII. Experimental results in a colon model (CM-1, Olympus, Tokyo, Japan) are shown to compare the efficacy of this metric in characterizing operator performance compared to standard metrics such as elapsed time, path length, and kinematics factors. The GII values for experts are significantly different from those of novices; our initial studies show that it can be as much as 1.45 times greater for the experts.