A Direct Drive Parallel Plane Piezoelectric Needle Positioning Robot for MRI Guided Intraspinal Injection

Recent developments in the field of cellular therapeutics have indicated the potential of stem cell injections directly to the spinal cord. Injections require either open surgery or a Magnetic Resonance Imaging (MRI) guided injection. Needle positioning during MRI imaging is a significant hurdle to direct spinal injection, as the small target region and interlaminar space require high positioning accuracy. Objective: To improve both the procedure time and positioning accuracy, an MRI guided robotic needle positioning system is developed. Methods: The robot uses linear piezoelectric motors to directly drive a parallel plane positioning mechanism. Feedback is provided through MRI during the orientation procedure. Both accuracy and repeatability of the robot are characterized. Results: This system is found to be capable of repeatability below 51 μm. Needle endpoint error is limited by imaging modality, but is validated to 156 μm. Conclusion: The reported robot and MRI image feedback system is capable of repeatable and accurate needle guide positioning. Significance: This high accuracy will result in a significant improvement to the workflow of spinal injection procedures.