Conventional versus robot-assisted MIS

Although MIS significantly reduces patient morbidity and length of hospital stay because of the small incision size, it has inherent drawbacks to the surgeon in terms of motor functioning and sensory capabilities. These include significantly degraded haptic feedback about instrument/tissue interactions, degraded visual feedback, and reduced dexterity and fine manipulation capability. Image-guided MIS attempts to use medical images (ultrasound, CT, etc.) to automate tasks through guiding surgical instruments to desired positions in the patient, generally either through incorporation with the control algorithm for a surgical robot or through virtual reality (e.g., image overlays on the endoscopic camera view in MIS) used to inform the surgeon. I am interested in the use of robotic and mechatronic systems, haptic interaction and image guidance for tackling the motor/sensory limitations that exist in MIS (or similar medical and biomedical applications).

A teleoperation system with haptic interaction

With a limited maneuverability of surgical instruments and restricted camera vision experienced in MIS, haptic feedback to the surgeon can be very helpful and make these kind of procedures more natural and less cumbersome. Studies have shown that the presence of haptic interaction in master-slave teleoperation, whereby a user operates from and receives force feedback via a master interface while a slave robot mimics the user’s hand maneuvers, enables significantly better control over tool-tissue interaction. The lack of haptic interaction has been identified as a major drawback of the current robotic-assisted surgical system, and a satisfactory solution has yet to be developed. 

My research pertained to devices and methods required for restoring haptic feedback in robot-assisted MIS. In terms of devices, I augmented a 3-DOF PHANToM haptic device with two additional degrees of freedom to form a surgeon-robot interface with full force reflection capabilities. I also designed a slave surgical end-effector with force sensing capabilities in all of the five degrees of freedom present in laparoscopic surgery. 

Left: (a) Haptic user interface for endoscopic interventions. Mechanisms for force reflection in the finger loops (b) and the roll mechanism (c).
Right: (a) Sensorized slave robot including the end-effector, the wrist, the twist motor, and the tip actuation assembly. (b) Details of the tip actuation assembly: the three tubes and two different detachable tips. (c) Gauges to measure bending moments. (d) Gauges to measure axial forces. (e) A gauge to measure torsional moment. (f) A load cell to find tip forces.