Rocker handle for endoscopic needle drivers. Technical and ergonomic evaluation by infrared motion analysis system.
BACKGROUND: The design of the handle on instruments for endoscopic surgery determines comfort and efficiency of use by the surgeon. This applies particularly to needle drivers. METHODS: A novel rocker handle was designed to provide holding comfort and intuitive function. This rocker handle was compared with a finger-loop handle in a study involving 10 surgeons who tied a total of 360 intracorporeal surgeons' knots in a random sequence. The end points in this study were the execution time, knot quality, and motion analysis parameters of the surgeon's elbow and shoulder joints. RESULTS: Intracorporeal surgeon's knots tied with the rocker-handle driver exhibited a better knot quality, although this was not significant (p = 0.097). A significant improvement in the knot quality score (KQS) was observed between the first and the second sessions (p = 0.045) with the rocker handle, whereas no significant learning effect was observed for the finger-loop handle. During intracorporeal knot tying, the angular velocity at the elbow and shoulder joints was consistently lower with the rocker handle, suggesting that more controlled movements are enacted by the surgeon with this handle. Discomfort from finger-loop pressure on the thumb was reported by 3 of 10 surgeons with the finger-loop handle, whereas no discomfort was reported for the rocker handle. CONCLUSIONS: The new rocker handle improves the quality of task performance by eliminating discomfort and reducing angular velocities at the shoulder and elbow joints during use.