A new type of mechanical instrument was developed to perform complex, minimally invasive procedures, also known as laparoscopic surgery. The technology could lead to less trauma for patients and shorter recovery times after surgery. The technology is based on National Science Foundation (NSF)-funded engineering research, and is being commercialized by FlexDex Surgical, a spinoff founded by University of Michigan engineers (Figure 1).
The handheld instrument provides the same benefits as robot-assisted surgery, such as greater precision and functionality, but at a lower cost compared to existing robotic surgical systems. The lower cost could result in new capabilities for rural hospitals and other medical centers that can’t afford more expensive systems. The technology gives surgeons a higher degree of dexterity and intuitive control than traditional laparoscopic instruments, which typically require significant training for surgeons, and can be difficult and tiresome to use.
Design of the system is based on parallel kinematics, or how different components in a mechanical system move in relation to one another, and how multiple chains of motion influence the performance of a system overall. This field could address a number of mechanical engineering challenges, from minimally invasive surgery and micro-devices, to manufacturing and metrology machines.
Inspired by nature, the researchers incorporated jointless structures that enable simplicity in design while providing smooth and precise motion. The instrument was created to feel and operate like an extension of a person’s own body (Figure 2).
The team created an abstract representation, known as a constraint map, of a person’s arm movement — from the shoulder, to the elbow, to the forearm, to the wrist, to the fingers — with each joint represented. The motions of each joint were mapped and extended beyond the hand to the motions of corresponding joints in the instrument, resulting in a streamlined mechanical instrument with precision pinchers.