Ergonomic Analysis of Laparoscopic Knot Tying

The laparoscopic knot-tying technique of novice and expert surgeons was analyzed to determine the ergonomics of both groups. Data capture was via an established virtual reality system, which includes a human force and torque feature. Novices had on average a lower angle of shoulder abduction than experts (25.64 degrees compared with 29.57 degrees) and a wider standard deviation than experts (5.41 compared with 4.46). Average time to completion of the task (three knots) was 433 seconds for novices against 310 seconds for experts. The mean torque magnitude did not simply increase with the angle of abduction. The angle at which torque was minimal for the shoulder was 27 degrees, and for the level of the third and fourth thoracic vertebrae, it was 22 degrees.