Abstract: Objective Analysis of mechanical measurements in laparo-endoscopic single-site surgery (LESS) is an important instrument design and surgical simulator.Aims of this study was to set up and evaluate the reliability and stability of noncontacting mechanical measurement system for instrument of LESS in company with digital image correlation technology.Methods The noncontacting mechanical measurement system was connected to a digital image correlation devices and a LESS manipulation platform (set up with a SILS Port and an inanimate laparoscopic trainer box).The correlation between the changes of deformation measurements (displacement and strain calculated by digital image correlation technology) and the change of workload (workout by the universal material testing machine)were evaluated.The experiment was repeated 8 times.Results A strong correlation was noticed between the changes of deformation measurements and the change of workload.The correlation coefficient was statistical significant (P<0.001).A high stability was well shown in all repetitions.Conclusions A noncontacting mechanical measurement system has been developed for LESS.Comprehensive mechanical parameters of SILS port can be obtained precisely by the digital image correlation technology.It is reliable and stable for the evaluation of instruments and manipulations in laparo-endoscopic single-site surgery by this system.

Key words: Laparo-endoscopic single-site surgery, Noncontacting measurement system, Digital image correlation technology