An Autoclavable Steerable Cannula Manual Deployment Device: Design and Accuracy Analysis

Abstract

Accessing a specific, predefined location identified in medical images is a common interventional task for biopsies and drug or therapy delivery. While conventional surgical needles provide little steerability, concentric tube continuum devices enable steering through curved trajectories. These devices are usually developed as robotic systems. However, manual actuation of concentric tube devices is particularly useful for initial transfer into the clinic since the Food and Drug Administration (FDA) and Institutional Review Board (IRB) approval process of manually operated devices is simple compared to their motorized counterparts. In this paper, we present a manual actuation device for the deployment of steerable cannulas. The design focuses on compactness, modularity, usability, and sterilizability. Further, the kinematic mapping from joint space to Cartesian space is detailed for an example concentric tube device. Assessment of the device’s accuracy was performed in free space, as well as in an image-guided surgery setting, using tracked 2D ultrasound.

Can concentric tube robots follow the leader?

“…If the moving tube has any precurved torsion (in the Frenet-Serret frame sense), an actuator will have to rotate the tube base, which is at negative arc length, to maintain a constant angle at s = O. If the fixed tube is moved at all after the moving tube has been extended, then the condition uix = 0 has been violated and the sum EI is no longer constant at the discontinuity where the fixed tube ends, meaning that the assumptions required for (10) are no longer valid. The follow-the-Ieader behavior will cease in this case (unless the precurvatures are both aligned and equal to one another) meaning that the shaft of the robot will deviate from the path traced previously by its tip.…”

“…To determine conditions for concentric tube follow-the leader deployment, we first assume a deployment sequence in which no tube which ends at an arc length s < L undergoes insertion or retraction, and that all tubes which advance axially to extend the robot's tip do so together.2 Continuing from (6), we can substitute in the robot model (9) and replace j=l (10) Note that all of the rotational configuration functions 'VJi ap pear in these conditions, as well as their time derivatives. The time derivatives of the precurvature functions also appear, and are nonzero for tubes that have non-constant precurvature and are undergoing insertion.…”

Minimally-invasive intracerebral hemorrhage removal using an active cannula

“…During this process, suction is used to aspirate the clot through the innermost tube of the active cannula. While many prior actuation units have been designed for concentric tube robots, this is the first robotic version (a manual version without motors was described in [17]) of which we are aware that is fully sterilizable and operatingroom ready. It is constructed entirely from autoclavable and biocompatible components, with a modular motor pack that can be bagged.…”

“…Also called a concentric tube continuum robot, this device consists of multiple concentric tubes that translate and rotate inside one another [13], [14], [15]. In this study, we use a version of the device similar to that previously used in soft tissue targeting applications in [16], [17], [18], [19], which consists of two tubes, the outer of which is straight. The straight tube initially acts exactly as an image-guided biopsy needle does, delivering the tip of the device to the hematoma, after which the precurved inner tube can be deployed and used as the aspiration channel to remove the clot.…”

A multi-arm hand-held robotic system for transurethral laser Prostate surgery

“…The forward kinematics of the two-tube robot with a straight outer tube and a constant curvature inner tube can be written in closed form [28]. Here, we assume that the outer tube is sufficiently stiff that the inner tube does not bend it significantly.…”