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This paper describes the design, development, and experimental evaluation of a novel steerable optical fiber for endoscopic laser surgery. The proposed device consists of an off-the shelf optical fiber installed into a flexible sheath (outer diameter: 1.6 mm) equipped with a custom distal steering mechanism. Thanks to its compact size, the proposed device can be easily deployed through the instrument channel of most commercially available clinical endoscopes. Among the procedures where we believe the new device could be beneficial, in this paper we focus on laser surgery of the larynx, i.e., the voice box. We report experimental findings, collected in in vitro models (additively-manufactured phantoms), demonstrating that the steerable fiber significantly expands surgical access, thus enabling physicians to address disease in locations that would normally be beyond reach.

This paper presents a computational model, based on the Finite Element Method (FEM), that simulates the thermal response of laser-irradiated tissue. This model seeks to address a gap in the current ecosystem of surgical robot simulators, which generally lack support for lasers and other energy-based end effectors. In the proposed model, the thermal dynamics of the tissue are calculated as the solution to a heat conduction problem with appropriate boundary conditions. The FEM formulation allows the model to capture complex phenomena, such as convection, which is crucial for creating realistic simulations. The accuracy of the model was verified via benchtop laser-tissue interaction experiments using agar tissue phantoms and ex-vivo chicken muscle. The results revealed an average Root-Mean-Square Error (RMSE) of less than 1.5 ^∘ C across most experimental conditions.

This letter describes the manufacturing and experimental characterization of novel stretchable strain sensors for continuum robots. The overarching goal of this research is to provide a new solution for the shape sensing of these devices. The sensors are fabricated via direct ink writing, an extrusion-based additive manufacturing technique. Electrically conductive material (i.e., the ink) is printed into traces whose electrical resistance varies in response to mechanical deformation. The principle of operation of stretchable strain sensors is analogous to that of conventional strain gauges, but with a significantly larger operational window thanks to their ability to withstand larger strain. Among the different conductive materials considered for this study, we opted to fabricate the sensors with a high-viscosity eutectic Gallium-Indium ink, which in initial testing exhibited high linearity ($R^{2} \approx$ 0.99), gauge factor $\approx$ 1, and negligible drift. Benefits of the proposed sensors include (i) ease of fabrication, as they can be conveniently printed in a matter of minutes; (ii) ease of installation, as they can simply be glued to the outside body of a robot; and (iii) ease of miniaturization, which enables integration into millimeter-sized continuum robots.

Objective: To develop a flexible miniaturized photoacoustic (PA) imaging probe for detecting anatomical structures during laparoscopic surgery. The proposed probe aimed to facilitate intraoperative detection of blood vessels and nerve bundles embedded in tissue not directly visible to the operating physician to preserve these delicate and vital structures. Methods: We modified a commercially available ultrasound laparoscopic probe by incorporating custom-fabricated side-illumination diffusing fibers that illuminate the probe's field of view. The probe geometry, including the position and orientation of the fibers and the emission angle, was determined using computational models of light propagation in the simulation and subsequently validated through experimental studies. Results: In wire phantom studies within an optical scattering medium, the probe achieved an imaging resolution of $0.43 \pm 0.09$ mm and a signal-to-noise ratio of $31.2\pm 1.84$ dB. We also conducted an ex vivo study using a rat model, demonstrating the successful detection of blood vessels and nerves. Conclusion: Our results indicate the viability of a side-illumination diffusing fiber PA imaging system for guidance during laparoscopic surgery. Significance: The potential clinical translation of this technology could enhance the preservation of critical vascular structures and nerves, thereby minimizing post-operative complications.

Combining laser technology with robotic precision and accuracy promises to introduce significant advances in minimally invasive surgical interventions. Lasers have already become a widespread tool in numerous surgical applications. They are proposed as a replacement for traditional tools (i.e., scalpels and electrocautery devices) to minimize surgical trauma, decrease healing times, and reduce the risk of postoperative complications. Compared to other energy sources, laser energy is wavelength‐dependent, allowing for preferential energy absorption in specific tissue types. This potentially leads to minimizing damage to healthy tissue and increasing surgical outcomes control and quality. Merging robotic control with laser techniques can help physicians achieve more accurate laser aiming and pave the way to automatic control of laser–tissue interactions in closed loop. Herein, a review of the state‐of‐the‐art robotic systems for laser surgery is presented. The goals of this paper are to present recent contributions in advanced intelligent systems for robot‐assisted laser surgery, provide readers with a better understanding of laser optics and the physics of laser–tissue interactions, discuss clinical applications of lasers in surgery, and provide guidance for future systems design.

Objective: To elucidate potential tissue coverage of side‐firing optical fibers in office‐based endoscopic laser treatment of larynx, as well as to demonstrate their enhanced ability to address challenging anatomic areas.Method: We performed a comparative study of four different fiber designs: a traditional forward‐facing fiber, and three side‐firing fibers that emit light at an angle of 45°, 70°, and 90°, respectively. The study was conducted in simulation, using eight three‐dimensional models of the human larynx generated from microtomography x‐ray scans. A computer program simulated the insertion of the endoscope into the larynx, and the Möller–Trumbore algorithm was used to simulate the application of laser light.Results: Side‐firing laser fibers increased potential tissue coverage by a mean of 50.2 (standard deviation [SD] 25.8), 73.8 (SD 41.3), and 84.0 (SD 47.6) percent for angles of 45°, 70°, and 90°, respectively, compared to forward‐facing fibers. Angled fibers provided access to areas of the larynx considered difficult to address by traditional methods, including the infraglottis, laryngeal ventricle, and right vocal fold.Conclusion: Simulation results suggest that side‐firing optical fibers have the potential to enhance anatomical access during in‐office endoscopic laser procedures in the larynx. Further research is needed to better understand the benefits and any potential risks or contraindications of side‐firing optical fibers.Level of Evidence: NA Laryngoscope, 133:1205–1210, 2023

In this paper, we present a study on the viability of fabricating Concentric Tube Robots using Multi Jet Fusion (MJF) of Nylon-12, a type of elastic polymer commonly used in additive manufacturing. We note that Nylon-12 was already evaluated for the purpose of building CTRs in prior work, but fabrication was performed with Selective Laser Sintering (SLS), which produced unsatisfactory results. Our study is the first study to evaluate the suitability of MJF to 3Dprint CTRs.

In this article, we propose a computational framework to estimate the physical properties that govern the thermal response of laser‐irradiated tissue. We focus in particular on two quantities, the absorption and scattering coefficients, which describe the optical absorption of light in the tissue and whose knowledge is vital to correctly plan medical laser treatments. To perform the estimation, we utilize an implementation of the ensemble Kalman filter (EnKF), a type of Bayesian filtering algorithm for data assimilation. Unlike prior approaches, in this work, we estimate the tissue optical properties based on observations of the tissue thermal response to laser irradiation. This method has the potential for straightforward implementation in a clinical setup, as it would only require a simple thermal sensor, for example, a miniaturized infrared camera. Because the optical properties of tissue can undergo shifts during laser exposure, we employ a variant of EnKF capable of tracking time‐varying parameters. Through simulated experimental studies, we demonstrate the ability of the proposed technique to identify the tissue optical properties and track their dynamic changes during laser exposure, while simultaneously tracking changes in the tissue temperature at locations beneath the surface. We further demonstrate the framework's capability in estimating additional unknown tissue properties (i.e., the volumetric heat capacity and thermal conductivity) along with the optical properties of interest.