Hughes S, Larmer J, Park J, Macrae H, Dubrowski A. Structural flexibility of laparoscopic instruments: implication for the design of virtual reality simulators. Stud Health Technol Inform. 2005; 111:201-3

PMID: 15718727


In accordance with the Practice Specificity Theory, training on models that closely resemble real life scenarios is most beneficial to learning. Research in the virtual reality (VR) simulation, as a potential teaching and evaluation tool, concentrated on the design of trainers to resemble operating room (OR) conditions. The purpose of the present investigation was to determine the structural flexibility of laparoscopic instruments of different materials and diameters under a wide range of stresses. Incorporating the mechanical properties of these instruments into the algorithms can prove to further increase the fidelity of VR simulators. The amount of deviation from pre-stress position in the instruments' shaft was measured with infrared markers and used as the index of structural flexibility. All instruments deviated considerably with the largest deviations observed for the small disposable, and lowest for the large reusable instruments. There was a linear relation between the stress and deviation for all instruments, which varied as a function of diameter. Similar instrument deviations were observed during cholecystectomy performed on porcine liver. Our findings show that laparoscopic instruments are not rigid bodies and are prone to significant deviations during standard laparoscopic procedures. This suggests that the structural flexibility of laparoscopic instruments should be modeled in the design of VR simulators.