Design of flexible smart robotic instruments for minimally invasive surgery

Abstract

Robots made their debut in the surgical field about 20 years ago in an attempt to introduce improvements in laparoscopy. With evolving technology, these robots became well appreciated for their stable performance, tremor cancelling and increased dexterity. On the other hand, at present, there is no strong clinical evidence that suggests that robotic surgery is preferable to laparoscopy. This is due to the fact that this discipline is still relatively young; therefore some challenges in traditional laparoscopic surgery still have to be addressed with an enhanced robot. Only a holistic approach to the design of surgical instruments will allow the next generation of surgical robots to realise their full potential and allow for a wider clinical uptake. This thesis focuses on the design and manufacture of a smart robotic surgical instrument, that addresses the main challenges posed by Transanal Endoscopic Microsurgery (TEM). The need for dexterity and triangulation is satisfied with the design of highly articulated end-effectors, while the instrument diameter is designed to be comparable to those of laparoscopic instruments. Furthermore, a viable manufacturing process was studied and proposed the production of components that would be difficult to produce with different manufacturing techniques. In order to reduce the amount of instrument interchanges that normally occur during surgery, one of the strategies followed during the design phase aimed to provide the instruments with some degree of multifunctionality. This also had the further benefit of allowing smoke evacuation that is a limiting factor in many small-lumen surgeries. Force sensing was also explored, proposing two different strategies. The first one uses a disposable sensor clip and the other proposes the design of a robotic coupling interface, which embeds force sensing into the couplings between the robot actuation and the robotic instrument. Furthermore, rigorous bench testing, user trials, in-vivo and ex-vivo studies have been carried out to validate the proposed surgical robot in different scenarios. The proposed surgical robot demonstrated great potential for its use in clinical practice, achieving suitable performance in all the tests performed. Bench tests demonstrated the robustness and repeatability of the performance, while user-based experiments showed its applicability and a quick learning curve. On the other hand, the design was based on the idea of producing a disposable instrument. Therefore, future work will address the possibility of using the instruments multiple times with re-sterilisation through autoclave.