Image-guided medical robotics
As traditional surgical procedures are replaced by minimally invasive ones offering lower complication rates and faster patient recovery times, percutaneous image-guided targeting of deep tissue volumes is increasingly being used for interventional clinical procedures such as thermal ablation, seed placement, intramuscular injection, tissue biopsy and electrical stimulation. However, current methods are manual and error-prone, requiring multiple trial-and-error needle insertions and imaging scans before the targeted tissue volume is successfully reached. In addition, only points along the needle’s axis can be reached in one insertion; to target large or irregularly shaped tissue volumes, multiple insertions are required, increasing the tissue damage sustained by the patient.
To address these issues, we created a mechanism for distal tip manipulation, consisting of a pre-curved stylet made out of superelastic Nitinol alloy. This stylet can be straightened and its distal tip retracted into a rigid outer cannula, then redeployed at a different angle, allowing for multiple locations within a cylindrical volume to be targeted in a single needle insertion. The instrument is mounted on a CT-compatible, robotically-controlled chassis allowing for more accurate needle alignment and insertion. The resulting device achieves low targeting errors of less than 2mm and a several-fold reduction in the number of needle insertions and imaging scans required for the procedure.