Jessica Burgner

A Telerobotic System for Transnasal Surgery

Mechanics-based models of concentric tube continuum robots have recently achieved a level of sophistication that makes it possible to begin to apply these robots to a variety of real-world clinical scenarios. Endonasal skull base surgery is one such application, where their small diameter and tentacle-like dexterity are particularly advantageous. In this paper, we provide the medical motivation for an endonasal surgical robot featuring concentric tube manipulators, and describe our model-based design and teleoperation methods, as well as a complete system incorporating image guidance. Experimental demonstrations using a laparoscopic training task, a cadaver reachability study, and a phantom tumor resection experiment illustrate that both novice and expert users can effectively teleoperate the system, and that skull base surgeons can use the robot to achieve their objectives in a realistic surgical scenario.

A Flexure-Based Steerable Needle: High Curvature With Reduced Tissue Damage

In the quest to design higher curvature bevel-steered needles, kinked bevel-tips have been one of the most successful approaches yet proposed. However, the price to be paid for enhancing steerability in this way has been increased tissue damage, since the prebent tip cuts a local helical path into tissue when axially rotated. This is problematic when closed-loop control is desired, because the controller will typically require the needle to rotate rapidly, and it is particularly problematic when duty cycling (i.e., continual needle spinning) is used to adjust curvature. In this paper, we propose a new flexure-based needle tip design that provides the enhanced steerability of kinked bevel-tip needles, while simultaneously minimizing tissue damage.

A bimanual teleoperated system for endonasal skull base surgery

We describe transnasal skull base surgery, including the current clinical procedure and the ways in which a robotic system has the potential to enhance the current standard of care. The available workspace is characterized by segmenting medical images and reconstructing the available 3D geometry. We then describe thin, “tentacle-like” robotic tools with shafts constructed from concentric tube robots, and an actuation unit designed to robotically control them in a teleoperated setting. Lastly, we discuss the results of a proof-of-concept study in a cadaveric specimen, illustrating the ability of the robot to access clinically relevant skull base targets.

On the computational design of concentric tube robots: Incorporating volume-based objectives

Concentric tube continuum robots provide an infinite-dimensional design space, consisting of individual tube space curves and other tube parameters. Even when design choices are made to restrict the design space to a small number of discrete parameters, ad hoc selection of parameter values to achieve coverage of a desired volume, in the presence of geometric workspace constraints, is essentially impossible - even for experienced researchers. General design algorithms proposed to date have focused on reaching a discrete set of specific points, and have made non-physical approximations in the robot model (most significantly assuming infinite torsional rigidity), to speed up model computation. In this paper, we extend prior algorithms to use more accurate models and incorporate volume-based objectives. These extensions are illustrated in a case study on the design of a concentric tube robot for endonasal pituitary surgery. We show that volume-based design optimization increases the reachable percentage of the surgical workspace by an average of approximately 50%, in comparison to various sets of manually selected design parameters. We conclude that volume-based objectives should be included in future multi-objective design optimization procedures for concentric tube continuum robots.

Robotic surgery for the sinuses and skull base: what are the possibilities and what are the obstacles?

Purpose of reviewRobotic surgery in otolaryngology – head and neck surgery has become a valuable tool in certain anatomic approaches; however, its application in surgery of the paranasal sinuses and anterior skull base is still in an investigatory phase and requires further evaluation. Recent findingsExisting robotic surgical systems face particular limitations in their application at the skull base because of instrument size and lack of variability. Unfortunately, only one system is available commercially that is applicable in the head and neck region and FDA approved for use in patients. This system, although advantageous in many otolaryngologic procedures, is difficult to use for endoscopic sinus and skull base surgery. However, other systems that target this anatomic subsite specifically are in development and show promise. Advances in the design of robotic arms, materials, and shape will potentially give surgeons a significant advantage over traditional endoscopic techniques. SummaryThis article will review the current applications of robotic systems in paranasal sinus and skull base surgery, describe the requirements of a robotic system for use in this type of surgery, and describe a system under development at our institution.

Comparison Study of Intraoperative Surface Acquisition Methods for Surgical Navigation

Soft-tissue image-guided interventions often require the digitization of organ surfaces for providing correspondence from medical images to the physical patient in the operating room. In this paper, the effect of several inexpensive surface acquisition techniques on target registration error and surface registration error (SRE) for soft tissue is investigated. A systematic approach is provided to compare image-to-physical registrations using three different methods of organ spatial digitization: 1) a tracked laser-range scanner (LRS), 2) a tracked pointer, and 3) a tracked conoscopic holography sensor (called a conoprobe). For each digitization method, surfaces of phantoms and biological tissues were acquired and registered to CT image volume counterparts. A comparison among these alignments demonstrated that registration errors were statistically smaller with the conoprobe than the tracked pointer and LRS ( p <; 0.01). In all acquisitions, the conoprobe outperformed the LRS and tracked pointer: for example, the arithmetic means of the SRE over all data acquisitions with a porcine liver were 1.73 ±0.77 mm, 3.25 ±0.78 mm, and 4.44 ±1.19 mm for the conoprobe, LRS, and tracked pointer, respectively. In a cadaveric kidney specimen, the arithmetic means of the SRE over all trials of the conoprobe and tracked pointer were 1.50 ±0.50 mm and 3.51 ±0.82 mm, respectively. Our results suggest that tissue displacements due to contact force and attempts to maintain contact with tissue, compromise registrations that are dependent on data acquired from a tracked surgical instrument and we provide an alternative method (tracked conoscopic holography) of digitizing surfaces for clinical usage. The tracked conoscopic holography device outperforms LRS acquisitions with respect to registration accuracy.

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

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 devices accuracy was performed in free space, as well as in an image-guided surgery setting, using tracked 2D ultrasound.

Planning and simulation of microsurgical laser bone ablation.

PurposeLaser ablation of hard tissue is not completely understood until now and not modeled for computer-assisted microsurgery. A precise planning and simulation is an essential step toward the usage of microsurgical laser bone ablation in the operating room.MethodsPlanning the volume for laser bone ablation is based on geometrical definitions. Shape and volume of the removed bone by single laser pulses were measured with a confocal microscope for modeling the microsurgical ablation. To remove the planned volume and to achieve smooth surfaces, a simulation of the laser pulse distribution is developed.ResultsThe confocal measurements show a clear dependency from laser energy and resulting depth. Two-dimensional Gaussian functions are fitting in these craters. Exemplarily three ablation layers were planned, simulated, executed and verified.ConclusionsTo model laser bone ablation in microsurgery the volume and shape of each laser pulse should be known and considered in the process of ablation planning and simulation.

Ex vivo accuracy evaluation for robot assisted laser bone ablation

Cutting bony tissue using short‐pulsed laser ablation enables contact‐free processing in arbitrary shapes and with considerably smaller incision widths compared with mechanical tools. This precise method necessitates assistance by robotic surgery.

A study on the theoretical and practical accuracy of conoscopic holography-based surface measurements: toward image registration in minimally invasive surgery.

Registered medical images can assist with surgical navigation and enable image‐guided therapy delivery. In soft tissues, surface‐based registration is often used and can be facilitated by laser surface scanning. Tracked conoscopic holography (which provides distance measurements) has been recently proposed as a minimally invasive way to obtain surface scans. Moving this technique from concept to clinical use requires a rigorous accuracy evaluation, which is the purpose of our paper.