Innovative polymer-based shaft instruments for minimally invasive surgery.

Minimally invasive surgery (MIS) has become an important field in the health care sector over the last decade. Still, there is the need for improving existing instruments and developing new tools providing increased functionality. This work presents innovative solutions and experimental results for a new generation of innovative polymer-based shaft instruments for minimally invasive surgery. The investigated components comprise a new kind of end-effector mechanism and an improved force transmission for actuating the effector. The new end-effectors consist of few discrete parts. They combine the advantages of compliant joints with those of conventional hinges ("hybrid effector"). The simple configuration will be advantageous during sterilization and, furthermore, is suitable for large-scale production by polymer technology. The effectors show low friction and low backlash properties and therefore high functionality. In addition to that we have developed a new kind of sensitive hydraulic force transmission which may replace the force transmission by push rods of conventional shaft instruments. The hydraulic force transmission is based on leakage-free embedding of the hydraulic fluid in modified polymer tubing. This specific hydraulic transmission component provides high efficiency force transmission and can be entirely fabricated by polymers. Both newly developed solutions reveal an increased functionality and due to their simple configuration can be manufactured by polymer technology, e.g. injection moulding. They show the potential for large-scale production of a new class of polymer-based shaft instruments for minimally invasive surgery.