A Highly Versatile Single-Port System for Minimally Invasive Surgery

Laparoscopic single-port surgery and natural orifice transluminal endoscopic surgery (NOTES) are two novel procedures with the aim to reduce trauma to the patient. Both of them are promising, but still highly dependent on the development of new, adequate support systems that are indispensable in order to perform such demanding interventions. Primarily, the requirements of a single-port system regarding surgical as well as technical aspects were investigated. Based on this knowledge, a new robot platform was developed to extend the limited possibilities of laparoscopic single-port surgery. The design of the developed single-port platform is presented here in detail. Two manipulators with 6 DOFs and a semi-rigid telescope with 5 DOFs are combined gas-tightly into one unit to perform surgeries through a single access. The hollow structure of the manipulator allows the introduction of flexible instruments. All the joints of the platform are actuated by flexible transmission mechanisms 2m from the platform at the periphery. This work also presents the kinematics of the flexible bending section and the manipulator that were verified and analyzed in a simulation with a simplified 3D model of the single-port platform. A velocity-based task-space control of the instruments was implemented in the simulation for kinematic analysis. The evaluation and assessment was carried out in a pick-and-place scenario. Moreover, the realized low-level control for the actuation of the manipulators in joint-space is presented. The workspace of the manipulator and the applicable forces were evaluated. Furthermore, the results of the accomplished in-vitro as well as in-vivo laparoscopic cholecystectomy are presented. Finally, an in-vitro NOTES cholecystectomy was performed with the semi-rigid platform to assess the potentials and challenges of transluminal surgery.