Robotic Actuation for Fetoscopic Interventions

Fetoscopic surgery is a form of minimally invasive surgery within the womb during pregnancy. It involves the introduction of small diameter, rigid instrumentation to fix defects in the placenta or developing fetus. Surgery within the uterine environment is technically very challenging due to the environment containing many critical structures that the instrumentation should not come into contact with. Robotics could potentially assist in these procedures through stabilising the instrumentation and introducing additional degrees of freedom at the tip of the instruments. This thesis presents the design, control and application of robotic manipulators positioned both outside and within the body to control imaging sensors. Custom endoscopes have been designed and fabricated with white light imaging sensors and all-optical ultrasound sensors. These endoscopes are held outside the body, proximal to the surgeon, by an articulated robotic manipulator. Additionally, within the body, distal to the surgeon, a continuum manipulator provides articulation at the tip of the instrument. The articulated robotic manipulator is constrained to the surgical incision point using a remote centre of motion which allows the endoscope to only pivot about the point and translate along the instrument axis. The continuum manipulator used is a form of concentric tube mechanism, which relies on the interactions between a curved tube of a super elastic material and a straight rigid tube, this can be controlled to deflect the tip of the endoscope from the main instrument axis. The developed endoscopes are then demonstrated through the execution of generated trajectories, which can be used to derive geometry of the imaging target and enhance the field of view of the imaging modalities.