In Vivo Demonstration of a Bevel Tip Steerable Needle with an Integrated Fluid Channel
Authors:   Mechanical Engineering, Vanderbilt University, McCabe E. , Rox M. , Emerson M. , Ertop T.E. , Fried I. , Fu M. ,   Vanderbilt University Medical Center, Hoelscher J. , Maldonado F. , Gillaspie E. A. ,   Division of Thoracic Surgery, Creighton University School of Medicine, CHI Health,   Kahlert School of Computing and Robotics Center, University of Utah,   University of North Carolina School of Medicine,   Computer Science, University of North Carolina at Chapel Hill, Akulian J. , Lee Y. Z. , Kuntz A. , Alterovitz R. , Webster III R. J. 
Published: September 2024

Bevel tip steerable needles have been the subject of intense study in surgical robotics over the past 20 years [1], [2]. This led to recent demonstration of autonomous needle steering in the lung in vivo in animals [3]. The pervasive paradigm in all of this past work has been that the needle acts in a manner analogous to a catheter’s guidewire. That is to say, the needle steers to the target, a plastic catheter-like sheath is slid over it, and then the needle is removed. The sheath provides a passage to the target for subsequent liquid injection or for tool insertion for biopsy or other therapy delivery (e.g. thermal ablation probes). While the sheath paradigm can work well, there remain scenarios where one may not wish to withdraw the needle. For example, one may wish to leave the sensor(s) embedded at the needle tip (e.g. magnetic tracking coils, thermal sensors, etc.) in place to monitor therapy delivery. Or one may wish to reposition the needle to several nearby targets to increase treatment volume or adjust the shape of the treatment volume. In such cases, multiple complete needle/tool withdrawal and insertion steps would be cumbersome and might also reduce accuracy. With this in mind, we propose a bevel tip steerable needle with an embedded fluid channel for liquid drug delivery (see Fig. 1). By using the helical laser pattern- ing proposed in [4], we can create a steerable needle large enough to house both a magnetic tracking coil and a fluid delivery lumen, but that is still flexible enough to steer in lung tissue. This is the first steerable needle through which injections can directly take place, and this would not be possible without the recent idea of laser MATERIALS AND METHODS Our steerable needle has a hinged bevel tip with a helical dovetail pattern laser cut into the distal shaft (Medical Device Imagineering, Inc., Somerset, NJ) us- ing a fiber laser (Rofin Inc.). We use the helical dovetail parameters as described by [4]. Within this 1.8 mm outer diameter (OD) needle, we insert a 30-gauge nitinol fluid channel (0.36 mm OD), and a 6 degree of freedom (DOF) magnetic tracking coil (0.9 mm OD), which are both fixed at the tip using a cyanoacrylate adhesive. The tip of the fluid channel is flush with the needle bevel as shown in Figure 1. Our group has previously developed imaging, planning, and control approaches for delivery of such needles into the lung bronchoscopically [3]. We experimentally demonstrated the efficacy of this new needle design in ex vivo and in vivo experiments, as shown in Figure 2. The veterinary team anesthetized the pig and administered a paralytic. They then performed a tracheotomy to bypass the porcine upper respira- tory structures, which geometrically differ from human anatomy and would make direct bronchoscope insertion challenging. patterning the needle’s shaft.