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

Abstract

UNLABELLED: 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.