What can the operator actually feel when performing a laparoscopy?

The designing of a laparoscopic simulator, particularly the parameterizing of a force feedback system, has drawn attention to the question of characterizing laparoscopic gestures and effecting quantitative measurement of the various interactions between the organs and the instruments used to operate in the case of animals. These measurements use an instrument previously developed by the authors' team. Laparoscopic gestures are characterized by a visual component and a haptic component. The visual component cannot, of course, be disregarded. The amplitude of the forces generated by interaction between organ and instrument in relation to that of the forces linked with other mechanical phenomena interfering with somesthesic information, such as friction of the operative instrument in the trocar or resistance of the abdominal wall to tilting movement, has led to a discussion about the extent of haptic components involved in the performance of laparoscopic gestures. After describing the measurement's device and the different forces applied on the surgical instrument, the authors describe the measurement of the rubbing strengths caused by the slippage of the instrument in the trocar and one of the elastic torques induced by the abdominal wall when the trocar in slanted. Comparison of values with those obtained during interactions with various organs shows that during some delicate surgical gestures, the influence of the instrument can disturb the haptic sensation. Interference of haptic sensation is greatest at maximal tilting angles and at maximal velocity of insertion and removal movement.