Alert button
Picture for Axel Krieger

Axel Krieger

Alert button

Member, IEEE

Bevel-Tip Needle Deflection Modeling, Simulation, and Validation in Multi-Layer Tissues

Nov 29, 2023
Yanzhou Wang, Lidia Al-Zogbi, Guanyun Liu, Jiawei Liu, Junichi Tokuda, Axel Krieger, Iulian Iordachita

Percutaneous needle insertions are commonly performed for diagnostic and therapeutic purposes as an effective alternative to more invasive surgical procedures. However, the outcome of needle-based approaches relies heavily on the accuracy of needle placement, which remains a challenge even with robot assistance and medical imaging guidance due to needle deflection caused by contact with soft tissues. In this paper, we present a novel mechanics-based 2D bevel-tip needle model that can account for the effect of nonlinear strain-dependent behavior of biological soft tissues under compression. Real-time finite element simulation allows multiple control inputs along the length of the needle with full three-degree-of-freedom (DOF) planar needle motions. Cross-validation studies using custom-designed multi-layer tissue phantoms as well as heterogeneous chicken breast tissues result in less than 1mm in-plane errors for insertions reaching depths of up to 61 mm, demonstrating the validity and generalizability of the proposed method.

Viaarxiv icon

Surgical Gym: A high-performance GPU-based platform for reinforcement learning with surgical robots

Oct 07, 2023
Samuel Schmidgall, Axel Krieger, Jason Eshraghian

Recent advances in robot-assisted surgery have resulted in progressively more precise, efficient, and minimally invasive procedures, sparking a new era of robotic surgical intervention. This enables doctors, in collaborative interaction with robots, to perform traditional or minimally invasive surgeries with improved outcomes through smaller incisions. Recent efforts are working toward making robotic surgery more autonomous which has the potential to reduce variability of surgical outcomes and reduce complication rates. Deep reinforcement learning methodologies offer scalable solutions for surgical automation, but their effectiveness relies on extensive data acquisition due to the absence of prior knowledge in successfully accomplishing tasks. Due to the intensive nature of simulated data collection, previous works have focused on making existing algorithms more efficient. In this work, we focus on making the simulator more efficient, making training data much more accessible than previously possible. We introduce Surgical Gym, an open-source high performance platform for surgical robot learning where both the physics simulation and reinforcement learning occur directly on the GPU. We demonstrate between 100-5000x faster training times compared with previous surgical learning platforms. The code is available at: https://github.com/SamuelSchmidgall/SurgicalGym.

Viaarxiv icon

Overcoming the Force Limitations of Magnetic Robotic Surgery: Impact-based Tetherless Suturing

Jul 03, 2021
Onder Erin, Xiaolong Liu, Jiawei Ge, Lamar Mair, Yotam Barnoy, Yancy Diaz-Mercado, Axel Krieger

Figure 1 for Overcoming the Force Limitations of Magnetic Robotic Surgery: Impact-based Tetherless Suturing
Figure 2 for Overcoming the Force Limitations of Magnetic Robotic Surgery: Impact-based Tetherless Suturing
Figure 3 for Overcoming the Force Limitations of Magnetic Robotic Surgery: Impact-based Tetherless Suturing
Figure 4 for Overcoming the Force Limitations of Magnetic Robotic Surgery: Impact-based Tetherless Suturing

Magnetic robotics obviate the physical connections between the actuators and end effectors resulting in ultra-minimally invasive surgeries. Even though such a wireless actuation method is highly advantageous in medical applications, the trade-off between the applied force and miniature magnetic end effector dimensions has been one of the main challenges in practical applications in clinically relevant conditions. This trade-off is crucial for applications where in-tissue penetration is required (e.g., needle access, biopsy, and suturing). To increase the forces of such magnetic miniature end effectors to practically useful levels, we propose an impact-force-based suturing needle that is capable of penetrating into in-vitro and ex-vivo samples with 3-DoF planar freedom (planar positioning and in-plane orienting). The proposed optimized design is a custom-built 12 G needle that can generate 1.16 N penetration force which is 56 times stronger than its magnetic counterparts with the same size without such an impact force. By containing the fast-moving permanent magnet within the needle in a confined tubular structure, the movement of the overall needle remains slow and easily controllable. The achieved force is in the range of tissue penetration limits allowing the needle to be able to penetrate through tissues to follow a suturing method in a teleoperated fashion. We demonstrated in-vitro needle penetration into a bacon strip and successful suturing of a gauze mesh onto an agar gel mimicking a hernia repair procedure.

* Journal, 5 figures 
Viaarxiv icon

Localization and Control of Magnetic Suture Needles in Cluttered Surgical Site with Blood and Tissue

May 20, 2021
Will Pryor, Yotam Barnoy, Suraj Raval, Xiaolong Liu, Lamar Mair, Daniel Lerner, Onder Erin, Gregory D. Hager, Yancy Diaz-Mercado, Axel Krieger

Figure 1 for Localization and Control of Magnetic Suture Needles in Cluttered Surgical Site with Blood and Tissue
Figure 2 for Localization and Control of Magnetic Suture Needles in Cluttered Surgical Site with Blood and Tissue
Figure 3 for Localization and Control of Magnetic Suture Needles in Cluttered Surgical Site with Blood and Tissue
Figure 4 for Localization and Control of Magnetic Suture Needles in Cluttered Surgical Site with Blood and Tissue

Real-time visual localization of needles is necessary for various surgical applications, including surgical automation and visual feedback. In this study we investigate localization and autonomous robotic control of needles in the context of our magneto-suturing system. Our system holds the potential for surgical manipulation with the benefit of minimal invasiveness and reduced patient side effects. However, the non-linear magnetic fields produce unintuitive forces and demand delicate position-based control that exceeds the capabilities of direct human manipulation. This makes automatic needle localization a necessity. Our localization method combines neural network-based segmentation and classical techniques, and we are able to consistently locate our needle with 0.73 mm RMS error in clean environments and 2.72 mm RMS error in challenging environments with blood and occlusion. The average localization RMS error is 2.16 mm for all environments we used in the experiments. We combine this localization method with our closed-loop feedback control system to demonstrate the further applicability of localization to autonomous control. Our needle is able to follow a running suture path in (1) no blood, no tissue; (2) heavy blood, no tissue; (3) no blood, with tissue; and (4) heavy blood, with tissue environments. The tip position tracking error ranges from 2.6 mm to 3.7 mm RMS, opening the door towards autonomous suturing tasks.

Viaarxiv icon

Medical Robots for Infectious Diseases: Lessons and Challenges from the COVID-19 Pandemic

Dec 14, 2020
Antonio Di Lallo, Robin R. Murphy, Axel Krieger, Junxi Zhu, Russell H. Taylor, Hao Su

Figure 1 for Medical Robots for Infectious Diseases: Lessons and Challenges from the COVID-19 Pandemic
Figure 2 for Medical Robots for Infectious Diseases: Lessons and Challenges from the COVID-19 Pandemic
Figure 3 for Medical Robots for Infectious Diseases: Lessons and Challenges from the COVID-19 Pandemic
Figure 4 for Medical Robots for Infectious Diseases: Lessons and Challenges from the COVID-19 Pandemic

Medical robots can play an important role in mitigating the spread of infectious diseases and delivering quality care to patients during the COVID-19 pandemic. Methods and procedures involving medical robots in the continuum of care, ranging from disease prevention, screening, diagnosis, treatment, and homecare have been extensively deployed and also present incredible opportunities for future development. This paper provides an overview of the current state-of-the-art, highlighting the enabling technologies and unmet needs for prospective technological advances within the next 5-10 years. We also identify key research and knowledge barriers that need to be addressed in developing effective and flexible solutions to ensure preparedness for rapid and scalable deployment to combat infectious diseases.

* 8 pages, 9 figures, publish in RA-magazine 
Viaarxiv icon

Telerobotic Operation of Intensive Care Unit Ventilators

Oct 11, 2020
Balazs P. Vagvolgyi, Mikhail Khrenov, Jonathan Cope, Anton Deguet, Peter Kazanzides, Sajid Manzoor, Russell H. Taylor, Axel Krieger

Figure 1 for Telerobotic Operation of Intensive Care Unit Ventilators
Figure 2 for Telerobotic Operation of Intensive Care Unit Ventilators
Figure 3 for Telerobotic Operation of Intensive Care Unit Ventilators
Figure 4 for Telerobotic Operation of Intensive Care Unit Ventilators

Since the first reports of a novel coronavirus (SARS-CoV-2) in December 2019, over 33 million people have been infected worldwide and approximately 1 million people worldwide have died from the disease caused by this virus, COVID-19. In the US alone, there have been approximately 7 million cases and over 200,000 deaths. This outbreak has placed an enormous strain on healthcare systems and workers. Severe cases require hospital care, and 8.5\% of patients require mechanical ventilation in an intensive care unit (ICU). One major challenge is the necessity for clinical care personnel to don and doff cumbersome personal protective equipment (PPE) in order to enter an ICU unit to make simple adjustments to ventilator settings. Although future ventilators and other ICU equipment may be controllable remotely through computer networks, the enormous installed base of existing ventilators do not have this capability. This paper reports the development of a simple, low cost telerobotic system that permits adjustment of ventilator settings from outside the ICU. The system consists of a small Cartesian robot capable of operating a ventilator touch screen with camera vision control via a wirelessly connected tablet master device located outside the room. Engineering system tests demonstrated that the open-loop mechanical repeatability of the device was 7.5\,mm, and that the average positioning error of the robotic finger under visual servoing control was 5.94\,mm. Successful usability tests in a simulated ICU environment were carried out and are reported. In addition to enabling a significant reduction in PPE consumption, the prototype system has been shown in a preliminary evaluation to significantly reduce the total time required for a respiratory therapist to perform typical setting adjustments on a commercial ventilator, including donning and doffing PPE, from 271 seconds to 109 seconds.

* 22 pages, 9 figures, 1 table; submitted to Frontiers in Robotics; in review 
Viaarxiv icon