Local magnetic actuation for laparoscopic surgery
In designing robotic instrument for laparoscopic surgery Local Magnetic Actuation can enable the transfer of a larger amount of mechanical power than what is possible to achieve by embedding actuators on board. This has the concrete potential to enhance both the dexterity and the miniaturization of the robotic surgical instrument.
The feasibility of this approach was demonstrated by the LMA-based tissue retractor represented in the video below. In this device, magnetic gears were used to transmit mechanical power from the external motor to the mechanism inside the retractor. The spinning motion of the IDM is fed to a custom mechanical train, which was designed to maximize the lifting force at the grasper and to fit the size constraints of a 12-mm surgical port. The device is 154 mm long, 12.5 mm in diameter, and weights 39.16 g.
When abdominal wall thickness is 2 cm, the retractor is able to lift more than ten times its own weight. The model is able to predict the performance with a relative error of 9.06±0.52%. Liver retraction trials demonstrates that the device can be inserted via laparoscopic access, does not require a dedicated port, and can perform organ retraction.