A shape memory alloy-actuated surgical instrument with compact volume.

Background: Surgical robotic systems have been proven to be accurate and dexterous during minimally invasive surgery (MIS). However, single incision laparoscopic surgery (SILS) requires more compact robotic arms with sufficient dexterity and output.

Methods: A shape memory alloy (SMA)-actuated instrument was adopted to assist operations. The instrument fixed at the slave site had three degrees of freedom (DOFs) and was driven by SMA wires, pitch, yaw, and grip, with an 8 mm diameter; a passive hydraulic support mechanism was placed in vitro.

Results: In vitro, the maximum force, velocity and accuracy were proven to be sufficient for medical application. In an animal study, the system was inserted into the abdomen; three more generic constraints were tested: medical gesture, safety, and implementation.

Conclusions: The robot was feasible and safe for multi-angle monitoring, grasping, and holding an organ. The SMA-actuated system was accurate and dexterous with minimal system volume.