Biocompatible Tracking System Advances Robotic Surgery

Under development at the Children's National Health System (CNHS) for use with the Smart Tissue Autonomous Robot (STAR) system, the three dimensional (3D) tracking system is comprised of small, biocompatible NIRF markers and a novel fused plenoptic and near-infrared (NIR) camera that enables the robot to overcome blood and tissue occlusion in an uncontrolled, rapidly changing surgical environment. The design takes advantage of the fact that near-infrared light can penetrate deeper into tissues than visual light.

In robotic experiments that compared the tracking accuracies of the system against standard optical tracking methods, the researchers observed that at speeds of 1 mm/second, tracking accuracies of 1.61 mm were achieved, which degraded only slightly (to 1.71 mm) when the NRIF markers were covered in blood and tissue. According to the researchers, using the markers to guide suturing during STAR surgery has the potential to improve manual and robot-assisted surgery and enhance accuracy. The study was published in the March 2017 issue of IEEE Transactions on Biomedical Engineering.

“A fundamental challenge in soft-tissue surgery is that target tissue moves and deforms, becomes occluded by blood or other tissue, which makes it difficult to differentiate from surrounding tissue,” said senior author Axel Krieger, PhD, of the CNSH Sheikh Zayed Institute for Pediatric Surgical Innovation. “By enabling accurate tracking of tools and tissue in the surgical environment, this innovative work has the potential to improve many applications for manual and robot-assisted surgery.”

The STAR system is a supervised robot that effectively removes the surgeon's hands from the procedure, relegating him to the role of director, with the robot itself working autonomously to plan and perform stitching or suturing. The STAR consists of tools for suturing, fluorescent and 3D imaging, force sensing, and submillimeter positioning. In addition, an intelligent software algorithm combines with the tracking system to guide and autonomously adjust the surgical plan as the tissue moves around and changes.