Defining the role of haptic feedback in minimally invasive surgery

The applications of Minimally Invasive Surgery (MIS) and Laparoscopy are rapidly expanding. Despite this expansion, the technology related to our understanding of the importance of haptic feedback related to laparoscopic surgery remains in its infancy. While many surgeons feel that the use of minimally invasive techniques eliminates force feedback and tactile sensation, the importance of haptics in MIS has not been fully evaluated. Moreover, there is considerable interest in the development of haptic simulators for MIS even though the importance of force feedback remains poorly understood. This study was designed to determine the ability of novice surgeons to interpret haptic feedback with respect to texture, shape and consistency of an object.

Subjects were presented objects in a random order and participants were blinded as to their identity. Inspection by direct palpation, palpation with conventional instruments, and palpation with laparoscopic instruments was performed on all objects. Statistical analysis of the data was performed using a Fischer exact probability test.

Direct palpation provided the greatest degree of haptic feedback and was associated with the highest accuracy for texture discrimination, shape discrimination, and consistency discrimination. A significant decrease in the ability to identify shapes was noted with both CI and LI. A significant decrease in the ability to differentiate consistency was noted for LI only. When comparing palpation with conventional instruments to palpation with laparoscopic instruments, there was no significant difference in shape or texture discrimination. There was, however, a significant decrease in consistency discrimination.

This data indicates that laparoscopic instruments do in fact provide the surgeon with haptic feedback. While the instruments change the information available to the surgeon, interpretation of the texture, shape and consistency of objects can be performed. Our ongoing work is directed at further defining force interactions. Through the use of force feedback impulse devices in VR simulators, one should be able to create a more realistic theatre in which the novice surgeon can learn operative skills that will readily translate into the operating room.