• soft pneumatic
• MIS
• end-effector

The evolution of technology led to several changes in the operative room, indeed revolutionizing surgical procedures. New techniques that have reduced patient trauma, shortened hospitalization, improved diagnostic accuracy and therapeutic outcome have been developed.
From the open surgery approach, MIS allowed to move towards the minimization of the number and the size of the scars on the patient, accessing to the human body cavity by mean of small incisions that allow the insertion of slim, long and rigid instruments. Clearly, this allowed shorter recovery times, less cost, less trauma because of the smaller wounds on the skin.
In traditional MIS, rigid instruments physically separate the surgeon from the patient while negatively affecting haptics, dexterity and visual motor coordination of the human hand. In laparoscopic techniques the human body naturally creates a mechanical motion constraint to the rigid surgical instrument, as it is limited by the small spatial volume at the entry point of the patient’s body. This leads to only four degrees of freedom (DOF), such as Roll, Pitch, Yaw, and translation, in respect to the fulcrum point at the trocar. Robotic systems can help to overcome limitations of traditional MIS. Tremor is removed and the movement is scaled resulting in a precise motion of the end-effector; in addition the fulcrum effect is removed using the digital master-slave setup. The introduction of the wrist articulation at the slave level enhances dexterity.
Systems with enhanced dexterity are one of the main needs for NOTES procedures, in which operating the target anatomy is not straightforward as in robotic assisted laparoscopy. The availability of dedicated modular tools that can be easily interchanged is fundamental for integration in modular robotic platforms.
Medical applications require safe micro-actuators with a quite high force and power density. The demand for such actuators for medical applications is rising, especially for advanced instruments for surgery. These applications require forces in the range of several Newton, high speed (10-100 mm/s) and large strokes (1-10 mm) to be generated in a confined volume. High output forces are difficult to obtain at the micro-scale. However, forces in the range of 1-2 N are sufficient for tissue manipulation and cutting when dedicated surgical tasks are performed. On the other hand, suturing tasks require slightly higher forces to hold the surgical needle. Recent studies showed that pneumatic and hydraulic micro-actuators are excellent candidates for combining high actuation force and strokes.
The implementation of an elastomer pneumatic actuator is interesting in MIS field, since elastomers actuators require low actuation stress or pressure for its deformation. Moreover, reliable and low-cost material can be used for the manufacturing of these actuators, thus resulting in new disposable and/or sterilizable devices.
In this paper, a modular end effector tool for manipulation and suturing suitable for MIS procedures, able to provide 5.78 N gripping force, and based on a compliant soft actuation system is presented.