Ultrasound-guided Robotic Needle Positioning: Integration and Evaluation of an End Effector for automatic Facet Joint Injections

Kurzfassung

In contemporary clinical practice, a considerable number of puncture interventions, including facet joint injections, are performed with the aid of imaging techniques. The most common imaging methods are either bulky or ionising, such as magnetic resonance imaging or fluoroscopy. Nevertheless, the utilisation of ultrasound imaging has been increasing in significance over recent years. This work employs a three-degree-of-freedom robotic end effector designed to carry out ultrasound-guided facet joint injections to develop an automation process that lets the user insert a needle at a specific position selected in the image and with a certain angle of inclination. To this end, a control model featuring several operation modes is developed in Simulink. Moreover, a graphical user interface programmed in Python provides an environment in which the user can determine the pose at which the needle is driven by the end effector. Additionally, an image-based assessment of the performance of the device is conducted. This evaluation yielded absolute position and orientation accuracies of approximately 5 mm and 2° respectively, and repeatabilities of approximately 1 mm and 3°. Despite the values obtained are promising and the integration of the end effector in an automatic insertion process has been accomplished, two main areas which still have room for improvement have been identified. Firstly, the use of an ultrasound transducer with a wider field of view that benefits from as much workspace of the end effector as possible, and secondly, the acquisition of a more accurate calibration matrix for the ultrasound probe.