In Vivo Safety and Feasibility of a CT-Guided Robotic Device for Percutaneous Needle Placement in Bone

Purpose: To evaluate the feasibility and accuracy of a robotic device used clinically in soft tissues (abdomen and lung), modified in design and workflow, to perform needle insertions in percutaneous skeletal procedures. Materials and Methods: The primary objective was safety (severe adverse events) of robotic-assisted insertion in this new application. Secondary objectives were feasibility (placement technical success), performance (rate of acceptable insertions), accuracy (lateral deviation), number of intermediate computed tomography (CT) scans, and tolerability (mild/moderate adverse events). Robotic-assisted insertions were performed by 6 interventional radiologists on 3 male pigs under general anesthesia. Needle trajectory was planned on the device software, and then needles were inserted with robotic guidance to reach the cortical bone. Intermediate CT was then performed to verify needle direction; if needed, the trajectory was modified, and robotic-assisted modified insertion into the target was performed. As many intermediate CT scans and trajectory modifications as needed by the operator were allowed. Results: Twenty-eight needles were inserted (10 in the spine and 18 in the pelvis). No adverse event was reported. Technical success rate was 96.4% (27/28). One insertion was not feasible after several robotic attempts. The placement success rate was 100% (27/27). After the planned intermediate CT scan, 13 (48.1%) of 27 trajectories did not require any modification, and 11 (40.7%) of 27 trajectories required a single modification. One needle was removed and replaced to achieve correct placement. Placement accuracy was similar for spinal and pelvic insertions, with a mean lateral deviation of 2.1 mm (SD ± 1.3). Conclusions: Preclinical robotic-assisted needle insertions in bone were safe and feasible, with satisfactory accuracy. A multicenter in-human study is ongoing to evaluate feasibility and safety for percutaneous bone ablation and consolidation procedures.