Robot Assisted Surgery: Four Arms Are Better Than Two

Roboticists at EPFL have combined multi-limb manipulation with advanced shared control augmentation for an unprecedented advance in the field of laparoscopic surgery. The results, published in The International Journal of Robotics Research, confirm the feasibility of the setup for reducing surgeon workload and improving precision and safety. Specialists have already been successfully trained on the system and clinical trials are ongoing in Geneva.

In a tight collaboration between the research group REHAssist and the Learning Algorithms and Systems Laboratory (LASA), PhD students Jacob Hernandez and Walid Amanhoud and a team of researchers developed a system that allows surgeons, in addition to their two natural arms, to control two additional robotic arms using haptic foot interfaces with five degrees of freedom. Each hand controls a manipulative instrument, while one foot controls an endoscope/camera, and another foot controls an actuated gripper. One key innovation of this system lies in the shared control between the surgeon and the robotic assistants. The control framework developed by the researchers ensures that the surgeon and robots can work collaboratively within a concurrent workspace while meeting the precision and safety demands of laparoscopic surgery.

According to Mohamed Bouri, head of the group REHAssist, “Actuators in the foot pedals give haptic feedback to the user, guiding the foot towards the target as if following an invisible field-of-forces, and also limit force and movement to ensure that erroneous feet movements do not endanger the patient.” Bouri goes on to say, "Our system opens up new possibilities for surgeons to perform 4-handed laparoscopic procedures, allowing a single person to do a task that is usually performed by two, sometimes three people.”

Minimise fatigue
Known as shared control, the robotics sometimes lead the surgeon’s control of the instrument as they predict where the surgeon wants to move. When tying a knot for example, the endoscope adjusts into the proper position and the gripper could move out of the way.

“Controlling four arms simultaneously, moreover with one’s feet, is far from routine and can be quite tiring. To reduce the complexity of the control, the robots actively assist the surgeon by coordinating their movements with the surgeon’s through active prediction of the surgeon’s intent and adaptive visual tracking of laparoscopic instruments with the camera. Additionally, assistance is offered for more accurate grasping of the tissues,” says Professor Aude Billard, head of LASA. Mohamed Bouri adds that, “by incorporating foot-controlled robotic assistants and shared control strategies, we reduce the mental and physical load on surgeons and we hypothesize to improve surgical outcomes."

Collaboration with surgeons
A comprehensive user study with practicing surgeons was conducted to evaluate the system's ease of use and effectiveness. According to Dr. Enrico Broennimann, who has participated in the trials in a collaboration with the Swiss Foundation for Innovation and Training in Surgery (SFITS), “The idea to actively use one’s feet to perform robotic-assisted surgery is a good idea, and it’s definitely a learnable skill. I’d like to see it implemented in the operating room, perhaps as a cockpit well away from the patient to increase ergonomics.”

While the system continues to be tested and improved, the results published in this study confirm the feasibility of performing four-arm surgical-like tasks without intensive training. The shared-control strategies implemented in the system were found to reduce task load, improve performance, increase fluency, and enhance coordination during laparoscopic tasks.

New real-time guidable-tip wire for surgically treating strokes

Our brains contain an intricate network of arteries that carry blood throughout the organ along winding paths. For neurosurgeons, following these paths with a wire – which is just a third of a millimeter in diameter and enters the body through the femoral artery – to reach an obstructed blood vessel can be tricky. For instance, if they want to point the wire in a different direction, they often have to pull the instrument out and then reinsert it, lengthening surgery times and increasing the risk of complications. But the new wire developed by Artiria is set to change all that. Its tip can be controlled by pressing a button on its handle, through an apparatus that runs entirely on mechanical forces. Artiria just received FDA clearance to test and market its system in the US.

The figures on strokes are startling. According to the World Health Organization, strokes are the leading cause of disability and the second-leading cause of death worldwide. One-fourth of people over 25 can expect to experience one during their lifetime. And when a stroke occurs, time is of the essence – rapid treatment can improve a patient’s prognosis considerably. “While strokes can be caused by a ruptured aneurysm, 80% of the time they’re due to a blood clot in the brain,” says Guillaume Petit-Pierre, Artiria co-founder and CEO. In combination with drug treatments to dissolve the clot, the surgical act, facilitated by the real-time visualization of the instruments by x-rays, makes it possible to extract the clot mechanically. The wire serves as a guide so that the other instruments needed for the operation can be inserted. Before creating their company, Petit-Pierre and Marc Boers – the other Artiria co-founder – spoke with several neurosurgeons and watched them operate several times in order to gain a thorough understanding of the techniques they use. The founders’ goal was to develop a device that would fit in seamlessly with existing procedures. “We were able to get the FDA clearance so quickly because our wire is similar to existing ones in so many respects,” says Petit-Pierre.

These micro-cuts, just a few tens of microns in size, are made from a superplastic alloy, ensuring the necessary flexibility of the wire tip while avoiding injury to the arterioles of the brain.

Guillaume Petit-Pierre

Useful for other types of post-stroke surgeries, too

Petit-Pierre and Boers tested their system on 3D-printed, clear-silicone models of cerebral arteries, and found that it didn’t create any major differences for neurosurgeons. It simply has an extra button on the handle that neurosurgeons can press when they want the tip to bend. A tiny pull wire relays the (slight) mechanical force created from pressing the button all along the structure of the instrument all the way to its 2-centimeter-long deflectable tip. The tip is reinforced on the side connected to the pull wire, and the other side is designed to follow the movement easily. The system may appear simple to the human eye, but fabricating its microscopic-scale parts was a considerable feat of engineering. "These micro-cuts, just a few tens of microns in size, are made from a superplastic alloy, ensuring the necessary flexibility of the wire tip while avoiding injury to the arterioles of the brain. The technological feat also consists in integrating a radio-opaque element into an extremely small volume, enabling the tip of the tool to be visualized during x-ray navigation", explains Guillaume Petit-Pierre. In order to guarantee flawless product cleanliness, the first versions of this system were assembled in EPFL's clean room.

Marc Boers and Guillaume Petit-Pierre © 2023 EPFL

The two founders are also exploring other applications for the underlying technology, which came out of EPFL’s Microsystems Laboratory 4 (LMIS4). “For example, we worked with the Wyss Center in Geneva to see if our wire could be used to lower spasms observed during hemorrhaging storkes,” says Petit-Pierre. Here, the wire could be used to target a specific artery using flexible thin-film electrodes. “There’s currently no effective way to treat cerebral vasospasms, even though they’re known to be a leading cause of disability and death after aneurysm-triggered strokes.”

Petit-Pierre and Boers are old friends and decided to create a startup around ten years ago, while on a backcountry skiing trip. At the time, Petit-Pierre worked in the medtech industry and Boers was already involved in other startups. Petit-Pierre did his PhD at LMIS4 – headed by Philippe Renaud, who was recently named professor emeritus – and the atmosphere there convinced him to try his hand at entrepreneurship. Some 25 businesses have spun off from Prof. Renaud’s lab, so there were plenty of role models to learn from. The core elements of Artiria’s system came from Petit-Pierre’s PhD thesis at LMIS4. With Boers he filed a patent application and created the company in 2019.

Artiria was awarded 2.7 million francs in funding under the European Innovation Council Accelerator Program – although the financing actually came from the Swiss government (SEFRI) since Switzerland no longer has a framework agreement with the EU – and has raised 4.1 million francs from investors. The medtech firm is ranked among Switzerland’s top 100 startups. The two founders plan to launch a more substantial funding round in the coming months, the proceeds of which will be used to expand its seven-person team and validate the product's clinical use.

Four School of Engineering Professors Honored with IEEE Awards

In recognition of their exceptional contributions to their respective fields, four professors from EPFL's School of Engineering have been awarded prestigious honors by the Institute of Electrical and Electronics Engineers (IEEE). The IEEE Awards Program and Best Paper awards are renowned for their acknowledgment of technical professionals who have made a significant impact on technology and society.

Professor Adrian Ionescu, head of the Nanoelectronic Devices Laboratory (Nanolab), has been honored with the 2024 IEEE Cledo Brunetti Award for his groundbreaking work in nanotechnology and technologies for microsystem miniaturization. Ionescu was awarded for his “leadership and contributions to the field of energy-efficient steep slope devices and technologies.”

Professor Andras Kis, head of the Laboratory of Nanoscale Electronics and Structures (LANES), has been granted the 2024 IEEE Lotfi A. Zadeh Award for Emerging Technologies. This accolade celebrates Kis's for his “pioneering work and breakthroughs on 2D materials and electronic devices.” His significant contributions to emerging technologies in recent years have propelled him to the forefront of his field.

Furthermore, Professor Mahsa Shoaran, head of the Integrated Neurotechnologies Laboratory (INL), and Professor Stéphanie Lacour, head of the Laboratory for Soft Bioelectronic Interfaces (LSBI), have jointly received the prestigious 2022 Best Brain Paper (IEEE and SSCS) award. Their winning paper describes a highly scalable and versatile closed-loop neuromodulation system-on-chip (SoC) capable of treating various neurological and psychiatric disorders. Through innovative circuit design techniques and hardware-algorithm co-optimization, Shoaran and Lacour achieved remarkable advancements in channel count, area, and energy efficiency, marking a significant step forward in the field.

The IEEE Awards Program, which has been honoring professionals for nearly a century, recognizes individuals who have made lasting impacts on technology, society, and the engineering profession. The distinguished awards bestowed upon EPFL Professors Ionescu, Kis, Shoaran, and Lacour underscore their outstanding contributions to their respective disciplines and highlight EPFL's commitment to excellence in research and innovation.

Deployable electrodes for minimally invasive craniosurgery

Stephanie Lacour’s specialty is the development of flexible electrodes that adapt to a moving body, providing more reliable connections with the nervous system. Her work is inherently interdisciplinary.

So when a neurosurgeon asked Lacour and her team to come up with minimally invasive electrodes for inserting through a human skull, they came up with an elegant solution that takes full advantage of their expertise in compliant electrodes, and inspired by soft robotics actuation. The results are published in Science Robotics.

The challenge? To insert a large cortical electrode array through a small hole in the skull, deploying the device in a space that measures about 1 mm between the skull and the surface of the brain – without damaging the brain.

“Minimally invasive neurotechnologies are essential approaches to offer efficient, patient-tailored therapies,” says Stéphanie Lacour, professor at EPFL Neuro X Institute. “We needed to design a miniaturized electrode array capable of folding, passing through a small hole in the skull and then deploying in a flat surface resting over the cortex. We then combined concepts from soft bioelectronics and soft robotics.”

From the shape of its spiraled arms, to the deployment of each arm on top of highly sensitive brain tissue, each aspect of this novel, deployable electrode is ingenious engineering.

The first prototype consists of an electrode array that fits through a hole 2 cm in diameter, but when deployed, extends across a surface that’s 4 cm in diameter. It has 6 spiraled-shaped arms, to maximize the surface area of the electrode array, and thus the number of electrodes in contact with the cortex. Straight arms result in uneven electrode distribution and less surface area in contact with the brain.

Somewhat like a spiraled butterfly intricately squeezed inside its cocoon before metamorphosis, the electrode array, complete with its spiraled-arms, is neatly folded up inside a cylindrical tube, i.e. the loader, ready for deployment through the small hole in the skull.

Thanks to an everting actuation mechanism inspired from soft robotics, each spiraled arm is gently deployed one at a time over sensitive brain tissue. “The beauty of the eversion mechanism is that we can deploy an arbitrary size of electrode with a constant and minimal compression on the brain,” says Sukho Song, lead author of the study. “The soft robotics community has been very much interested in this eversion mechanism because it has been bio-inspired. This eversion mechanism can emulate the growth of tree roots, and there are no limitations in terms of how much tree roots can grow.”

The electrode array actually looks like a kind of rubber glove, with flexible electrodes patterned on one side of each spiral-shaped finger. The glove is inverted, or turned inside-out, and folded inside of the cylindrical loader. For deployment, liquid is inserted into each inverted finger, one at a time, turning the inverted finger right side out as it unfolds over the brain.

Song also explored the idea of rolling up the arm of the electrode as a strategy for deployment. But the longer the arm, the thicker it becomes when rolled up. If the rolled-up electrode becomes too thick, then it would inevitably take up too much room between the skull and the brain, placing dangerous amounts of pressure on the brain tissue.

The electrode pattern is produced by evaporation of flexible gold onto very compliant elastomer materials.

So far, the deployable electrode array has been successfully tested in a mini-pig. The soft neurotechnology will now be scaled by Neurosoft Bioelectronics, an EPFL spin-off from the Laboratory for Soft Bioelectronic Interfaces, that will lead its clinical translation. The spin-off was recently granted 2.5 million CHF Swiss Accelerator by Innosuisse.

Neuro-X calls for application to its Postdoctoral Fellowships Program

The Neuro X Institute at EPFL calls for applications to its new Postdoctoral Fellowships Program, to carry out innovative research at the crossroads of neuroscience, neuroengineering and neurocomputation, aiming at clinical translation. The program intends to promote young researchers with bold ideas in neurotechnology and provide a ramp towards academic independence. Fellows will be able to carry out their research project within one Neuro X laboratory for up to 24 months.

See the linked Program description for more details.

Deadline is May 31st, 2023, for an expected start in September 2023.

Prof Dimitri Van De Ville elevated as EURASIP fellow

In recognition of outstanding achievements in the broad field of Signal Processing, the European Association for Signal Processing (EURASIP) has elevated Dimitri Van De Ville to “EURASIP Fellow”, the Association's most prestigious honour,

« For contributions to biomedical image and signal processing and application to functional brain imaging »

Each year EURASIP elevates a maximum of four scholars to this honor, which will be delivered to Dimitri Van De Ville during the Opening and Awards Ceremony at EUSIPCO 2022 (https://eusipco2023.org), which will be held in Helsinki, Finland, 4 September 2023 - 8 September 2023.

Congratulations to Prof Dimitri Van De Ville!

A neuro-chip to manage brain disorders

Mahsa Shoaran of the Integrated Neurotechnologies Laboratory in the School of Engineering collaborated with Stéphanie Lacour in the Laboratory for Soft Bioelectronic Interfaces to develop NeuralTree: a closed-loop neuromodulation system-on-chip that can detect and alleviate disease symptoms. Thanks to a 256-channel high-resolution sensing array and an energy-efficient machine learning processor, the system can extract and classify a broad set of biomarkers from real patient data and animal models of disease in-vivo, leading to a high degree of accuracy in symptom prediction.

“NeuralTree benefits from the accuracy of a neural network and the hardware efficiency of a decision tree algorithm,” Shoaran says. “It’s the first time we’ve been able to integrate such a complex, yet energy-efficient neural interface for binary classification tasks, such as seizure or tremor detection, as well as multi-class tasks such as finger movement classification for neuroprosthetic applications.”

Their results were presented at the 2022 IEEE International Solid-State Circuits Conference and published in the IEEE Journal of Solid-State Circuits, the flagship journal of the integrated circuits community.

Efficiency, scalability, and versatility

NeuralTree functions by extracting neural biomarkers – patterns of electrical signals known to be associated with certain neurological disorders – from brain waves. It then classifies the signals and indicates whether they herald an impending epileptic seizure or Parkinsonian tremor, for example. If a symptom is detected, a neurostimulator – also located on the chip – is activated, sending an electrical pulse to block it.

Shoaran explains that NeuralTree’s unique design gives the system an unprecedented degree of efficiency and versatility compared to the state-of-the-art. The chip boasts 256 input channels, compared to 32 for previous machine-learning-embedded devices, allowing more high-resolution data to be processed on the implant. The chip’s area-efficient design means that it is also extremely small (3.48mm²), giving it great potential for scalability to more channels. The integration of an ‘energy-aware’ learning algorithm – which penalizes features that consume a lot of power – also makes NeuralTree highly energy efficient.

In addition to these advantages, the system can detect a broader range of symptoms than other devices, which until now have focused primarily on epileptic seizure detection. The chip’s machine learning algorithm was trained on datasets from both epilepsy and Parkinson’s disease patients, and accurately classified pre-recorded neural signals from both categories.

“To the best of our knowledge, this is the first demonstration of Parkinsonian tremor detection with an on-chip classifier,” Shoaran says.

Self-updating algorithms

Shoaran is passionate about making neural interfaces more intelligent to enable more effective disease control, and she is already looking ahead to further innovations.

“Eventually, we can use neural interfaces for many different disorders, and we need algorithmic ideas and advances in chip design to make this happen. This work is very interdisciplinary, and so it also requires collaborating with labs like the Laboratory for Soft Bioelectronic Interfaces, which can develop state-of-the-art neural electrodes, or labs with access to high-quality patient data.”

As a next step, she is interested in enabling on-chip algorithmic updates to keep up with the evolution of neural signals.

“Neural signals change, and so over time the performance of a neural interface will decline. We are always trying to make algorithms more accurate and reliable, and one way to do that would be to enable on-chip updates, or algorithms that can update themselves.”