Tobias Leuthold's research works | ETH Zurich and other places

This page lists works of an author who doesn't have a ResearchGate profile or hasn't added the works to their profile yet. It is automatically generated from public (personal) data to further our legitimate goal of comprehensive and accurate scientific recordkeeping. If you are this author and want this page removed, please let us know.

Controlled tissue soldering for seamless tissue fusion in MIS. a) Illustration showing the advantages of laser tissue soldering compared to conventional suturing of soft tissues. b) Schematic of laser tissue solder integration into robotic minimally invasive surgery. c) The components of the solder paste (shown in the photo) are illustrated schematically, along with a schematic of the soldering mechanism. d) Fluorescence spectra collected at two different nanothermometer temperatures (normalized intensity). The ratio of the two fluorescence emission peaks of BiVO4:Nd³⁺ are used for non‐contact temperature measurements. e) Calibration plot used to calculate the temperature from the fluorescence intensity ratio FIR (a = 1.33 ± 0.03, b = −1.32 ± 0.01 K⁻¹ are the values of the fit y = a + b × x with y = ln(FIR) and x = 1/T; PB = Prediction Band).

Automatized feedback for controlled local heating. a) Feedback‐controlled soldering allows for soldering at various temperatures (60, 70, 80 °C), achieving the target temperature in less than 10 s for temperatures needed in tissue soldering (top plot). Temperature control is kept by modulating the laser power (middle plot) and based on the signal strength (bottom plot). (d = 10 mm) b) The target temperature (here 63 °C) is reached also at different distances of the fibers from the solder paste, however, with a slower response at higher distances. c) The PID parameters can be tuned to obtain a responsive behavior, at the cost of an initial small temperature overshoot. (d = 10 mm, T = 63 °C) d) The feedback mechanism can be employed also while the optical fiber‐endoscope is moved over the wound (as illustrated in the top part): two pieces of solder paste are placed on a piece of pig intestine and the fibers are moved over them. The controller is also able to discriminate when the paste is being irradiated (green areas) and when it is above healthy tissue (red areas), automatically lowering the laser power to a safe level (15%). (d = 10 mm, T = 60 °C). e) Illustration of the feedback loop setup used for paste recognition and soldering: the solder paste is placed on ex vivo tissue (pig dura mater), one fiber is used for laser excitation, one fiber is used for fluorescence measurement, and a thermal camera is used as reference. The nanothermometry spectra measured by the spectrometer are used to control the feedback loop through an Arduino that modulates the laser power. f) Images show liver soldered with manual and power‐controlled methods. Manual soldering shows burnt areas, uneven bonding, and tissue dehydration, while power‐controlled soldering produces a uniform, damage‐free seam.

Machine learning approach for low‐cost thermal distribution imaging. a) Illustration of how a multifibre system coupled with the upscaling Convolutional Neural Network (CNN) can reconstruct the thermal distribution during laser excitation starting from a low‐resolution hyperspectral image. b) Upscaling CNN architecture. c) Performance of the trained CNN showed with training loss. d) Examples of simulated data reconstructed using the upscaling CNN. e) Experimental setup used to collect the fluorescence from each individual fiber featuring inexpensive equipment: the fluorescence light is collected by a displaceable fiber and is lead, after being filtered, to a spectrometer. The signal is used to calculate the temperature which is compared to a reference thermal camera. f) Examples of experimental data reconstructed using the upscaling CNN. (FOV = 0.25 cm).

Multicore fiber approach for thermal imaging in robotic soldering. a) Schematic of the setup used to measure the thermal distribution during soldering, featuring two NIR cameras to detect the fluorescence of the two emission peaks. b) Pictures of the robotic systems with integrated tissue soldering equipment. Left side: telemanipulated robot (Dexter, Distalmotion SA); right side: programmable robot (LBR Med 14 820, KUKA). For the telemanipulated robot, the dual‐fiber system for automatized feedback‐controlled soldering is incorporated with the instrument of the left robotic arm, while the imaging fiber is spatially manipulated using a gripper instrument of the right robotic arm. For the programmable robot, a custom‐made attachment in which all the fibers are placed is used for the integration. c) Example of images recorded with the two different filters during soldering of a piece of solder paste. The FIR is calculated from the two images that represent the fluorescence of the two peaks (acq. time = 500 ms). The FIR is then used to compute the temperature distribution of the solder paste (FOV = 0.6 cm). d) A machine learning algorithm is developed and applied for the automatic detection and localization of the paste during surgery, information that can be used to automatically define and generate a soldering path for the robot. Top: image of the paste on a porcine aorta used for training. Bottom: picture taken by a laparoscope at the start of robotic soldering. e) The thermal imaging through fluorescence can be implemented together with the automatized feedback‐controlled soldering. This reconstructed image, made by adding images taken while the soldering probe was moving, shows how the temperature is kept at the target temperature (60 °C) throughout the entire soldering path.

Application in laparoscopic surgery in vivo. a) Soldering performed laparoscopically on an in vivo porcine model, with the optical fibers passing through a trocar. b) The solder paste is placed in the groove of a grasper for easy insertion inside the abdominal cavity. c) Then, the paste can be taken and positioned with a second grasper. The optical fibers are directed to the paste and soldering is performed. d) Histology of the soldered liver over a surgical incision compared with a healthy control, showing no visible thermal damage and good adhesion. e) Tensile strength values of soldered liver compared to sutured liver, showing that soldering achieves higher bond strength due to its uniform adhesion across the tissue, which distributes stress more evenly and minimizes localized tearing common with sutures.

Robotic Laser Tissue Soldering for Atraumatic Soft Tissue Fusion Guided by Fluorescent Nanothermometry

November 2024

31 Reads

[...]

Minimally invasive surgical techniques, including endoscopic and robotic procedures, continue to revolutionize patient care, for their ability to minimize surgical trauma, thus promoting faster recovery and reduced hospital stays. Yet, the suturing of soft tissues ensuring damage‐free tissue bonding during these procedures remains challenging due to missing haptics and the fulcrum effect. Laser tissue soldering has potential in overcoming these issues, offering atraumatic seamless tissue fusion. To ensure the precision and safety of laser tissue soldering, the study introduces feedback‐controlled fluorescent nanothermometry‐guided laser tissue soldering using nanoparticle‐protein solders within endoscopic and robotic contexts. Temperature‐sensitive fluorescent nanoparticles embedded in the solder provide surgeons with immediate feedback on tissue temperatures during laser application, all while within the confines of minimally invasive (robotic) surgical setups. By integrating fluorescent nanothermometry‐guided laser tissue surgery into endoscopic and robotic surgery, the study paves the way for a new approach for safe and atraumatic soft tissue joining, especially in regions where traditional suturing is unfeasible.

Download

Robotic Laser Tissue Soldering for Damage-free Soft Tissue Fusion Guided by Fluorescent Nanothermometry

Preprint

March 2024

23 Reads

[...]

Minimally invasive surgical techniques, including endoscopic and robotic procedures, continue to revolutionize patient care, for their ability to minimize surgical trauma, thus promoting faster recovery and reduced hospital stays. Yet, the suturing of soft tissues ensuring damage-free tissue bonding during these procedures remains challenging due to missing haptics and the fulcrum effect. Laser tissue soldering has potential in overcoming these issues, offering damage-free seamless tissue fusion. To ensure the precision and safety of laser tissue soldering, we introduce feedback controlled fluorescent nanothermometry-guided laser tissue soldering using nanoparticle-protein solders within endoscopic and robotic contexts. Temperature-sensitive fluorescent nanoparticles embedded in the solder provide surgeons with immediate feedback on tissue temperatures during laser application, all while within the confines of minimally invasive (robotic) surgical setups. By integrating fluorescent nanothermometry-guided laser tissue surgery into endoscopic and robotic surgery, we pave the way for a new approach for safe and atraumatic soft tissue joining, especially in regions where traditional suturing is unfeasible.

Tobias Leuthold’s research while affiliated with ETH Zurich and other places

What is this page?

Publications (2)