The role of tactile feedback in laparoscopic surgery.

Two experiments aiming at comparing palpation with gloved fingers, conventional laparoscopic instruments, and a laparoscopic instrument with a sensor array attached to its end effector are described. The sensor array provides the surgeon with visually presented tactile information. Fifteen subjects were asked to discriminate hardness and size of objects (rubber balls hidden in pig's intestine) with the 3 palpation methods. The experiments showed that the gloved fingers are better at differentiating hardness and size compared with conventional laparoscopic instruments and the instrument with sensor. There was no significant difference between conventional instruments and the instrument with sensor, although the results showed a higher average score with the instrument with sensor. This indicates that visual presentation may not be an ideal way of presenting tactile information. It also indicates that the presence of the array does not make the task more difficult.