Smaller tools with better maneuverability and more precise control, new imaging approaches, and advanced software applications will improve patient outcomes
Surgeons around the world are now using robot-assisted tech to help them perform minimally invasive operations ranging from hernia repair and gall bladder removal to knee replacement and cancer-related colectomy, often manipulating the surgical tools from a computer console some distance from the patient. With names like da Vinci, Aquabeam, and Mako, robotic surgical technologies are becoming more common. As an example, industry powerhouse Intuitive reported in late 2021 that the number of surgical procedures using its robotic da Vinci system had topped 10 million globally .
Why is the medical industry so interested in robots for these laparoscopic or keyhole operations? One of the biggest advantages is that they help the average surgeon perform at a higher level, according to Robert Webster, Ph.D., Vanderbilt University’s Richard A. Schroeder professor of mechanical engineering and head of Vanderbilt’s Medical Engineering and Discovery Laboratory. “You’d be amazed at what the best-of-the-best doctors can do with just a straight endoscope that has a laser fiber sticking out of it. They free-hand that crazy, long, metal rod, lever it around, and do really delicate surgeries out of the tip,” he described. “But a typical surgeon doesn’t have that skill set. So what surgical robotics is really good at is democratizing health care, and conveying the skills of the truly elite doctors to all surgeons, and therefore to all patients.”
That is a main goal in the field, agreed Axel Krieger, Ph.D., assistant professor of mechanical engineering, and head of the Intelligent Medical Robotic Systems and Equipment Laboratory at Johns Hopkins University (JHU). “I really feel there is a new generation of medical robots coming, ones that have more intelligence, can react to changes, and can help a surgeon who might not have a lot of experience with a certain complex operation, or maybe does have the experience but is just having a bad day,” he remarked.
To get the most from surgical robotics, researchers at universities and tech companies are working on advanced capabilities, including smaller tools with better maneuverability and more precise control, new imaging approaches to provide heightened views, and software applications to help surgeries go as smoothly as possible and improve outcomes.
Leveraging old to build new
Recent advances showcase different approaches to surgical robotics. For Vicarious Surgical  of Waltham, MA, USA, that involves building on current capabilities to take robotic surgery to the next level, said Sammy Khalifa, company co-founder and CTO (Figure 1). “We are leveraging a lot of the development and the progress that have happened in the last 15–20 years on microprocessors and on cellphone-camera sensors, and we’re integrating all of that into our device (to deliver) extraordinary visualization, incredible ease of use, and unprecedented access within the patient from a single incision, and at a price point that will hopefully bring the benefits of minimally invasive surgery to the masses.”
One of Vicarious Surgical’s innovations is the camera. “It has four degrees of freedom, so it can look left-right and up-down, it can roll, and it can move in and out,” Khalifa said. “The combination of all of that really allows the surgeons to look wherever they want, whereas right now, yes, some of (the systems) have a little ability to look right, left, up, and down, but we can literally turn all the way backward and look at where we’re coming into the patient, which will open the door to a lot of procedures in the future.”
Company researchers accomplished the maneuverability of the robotic camera as well as the surgical tool in part through advances in cable-driven robotics, Khalifa said. “In a typical cable-driven robotic system, you have a set of cables that run down the arm to the joints to move them, and the more proximal joints have cables that run to the more distal joints, so those cables impart a lot of force on that proximal joint. And if you have 8 or 9 degrees of freedom like our system does, you have a lot of cables running through and imparting a lot of force on that proximal joint that can decrease its strength and capability, but we have solved that problem,” he stated. While he could not provide all of the details due to proprietary reasons, he would say that the company’s solution included using a decoupled actuator and careful materials selection for the mechanical cable pathway, along with some “fancy control techniques.”
The company looks forward to demonstrating the beta version of its Vicarious Surgical System by the end of 2022 and is currently planning an FDA submission in 2024, Khalifa said (Figure 2). As that proceeds, he added, company researchers are already working on a follow-up to the system software that integrates artificial intelligence and machine learning, along with a multitude of sensors, which can fit into the “unique architecture” of the device. Together, he said, the additional sensors and software upgrade should enhance structure detection to aid the accuracy of the surgery and to provide virtual “guardrails” around non-surgical tissues to shield them during procedures.
“We’re targeting unprecedented ease of use. That means reducing the learning curve and making it so easy to use that you don’t need a hundred procedures to become a skilled surgeon,” Khalifa added. Ultimately, the goal is to “bring the benefits of a complex procedure, such as minimally invasive laparoscopy, to more patients.”
Webster’s approach to innovation in surgical robotics begins by spending time with surgeons, often in operating rooms at Vanderbilt University Medical Center, where he has an engineering lab (Figure 3). “I don’t bring a specific technology into the hospital; I go into the hospital and I look for problems, and then I apply everything we know as engineers to try to solve those problems,” he said. One very evident need in laparoscopic surgery is robots small enough to snake through the tiny ports of an endoscope. “You need robots that are about the size of needles to be able to reach through those ports,” he asserted. “That’s where our concentric-tube robot comes in.”
The concentric-tube robot is an ultrathin, telescoping collection of nesting tubes, something akin to an old-school TV antenna, but with each tubed section highly flexible and shaped with a curved tip. “With this arrangement, you can hold onto the tubes at the back end, twist them back and forth, slide them in and out, and do surgery in a very small space at the tip of that endoscope,” Webster described. This approach eliminates the wires and pulleys of today’s robotic robots that allow them to bend, he said, and “encodes all of that into the outside wall of the tube. That, along with that pre-curved shape, is what lets you really shrink down the size of the robot.”
Development of the concentric-tube robot was not easy. In fact, Webster said, it took two doctoral dissertations to model the shape that results when a collection of nested, curved tubes is rotated and extended. “That’s tricky, because the tubes are all bending and twisting one another, and in very interesting ways,” he said.
While puzzling over that mind-boggling geometry problem, Webster and three colleagues launched the spinoff company Virtuoso Surgical  to further develop the concentric-tube approach into a working robotic system ,  (Figure 4). That system will be undergoing final testing over the next year in preparation for the first human trials in early 2024, he said. Those trials will focus on natural orifice endoscopic surgeries, such as precisely removing bladder tumors or excess prostate tissue, as well as uterine fibroids and scar tissue. “That’s where we’re going with our research,” he said, “and I think that’s what is really going to have the next big transformative effect on the field of robotic surgery.”
As that moves forward, Webster’s Vanderbilt lab is also working on other robotic surgery technologies, including a National Institutes of Health-funded, collaborative project with the Intuitive Corporation, Sunnyvale, CA, USA. This is an all-software project designed to improve imaging in the da Vinci robotic system by adding information from the pre-operative computed tomography scan, so the surgeon can see both the endoscope image and the nicely segmented CT images.
“What this does is essentially give the surgeon a GPS display, but in 3-D, so they can see not only exactly where their robot tool is, but also all of the subsurface anatomy before they make it cut,” he said. In other words, the surgeon can hover the tool above the tissue and spot and avoid an otherwise-hidden blood vessel, or see exactly where to cut to remove a tumor. And they can see all that in real time. Thinking about the diversity of projects he is working on, he added, “That’s the beauty of being at a university. We can do brand new things like these tiny needle-sized robots, and we can also help make existing systems better by collaborating with companies that are out there and have an impact right away. For instance, if we get the software for Intuitive working right, then the company can immediately do a software upgrade to all their robots, and it will get out there worldwide to all the systems that are already installed.”
One of the most publicized examples of the promise of robotic surgeries came this past year when Krieger and his colleagues at JHU reported the first robotic system to plan, adapt, and execute laparoscopic surgery . “Current medical robots require the surgeon to be at the console using hand-held controllers to manually direct every path the tool takes and every step it makes. By comparison, this new technology puts the surgeon in a supervisory role instead, with the robot doing its work automatically,” Krieger said (Figure 5).
Conducted in four live pigs, the procedure used the group’s Smart Tissue Autonomous Robot (STAR) to reconnect two ends of intestine, a particularly exacting technique that requires meticulous suturing to prevent post-surgical leakage and potentially fatal infection. The surgery, called intestinal anastomosis, is a common procedure to remove diseased tissue in humans (Figure 6). “STAR looks at the surgical scene, calculates where to place each stitch, and displays the surgical plan to the surgeon. After the plan is accepted, then the robot goes in and performs every stitch automatically, and the operating surgeon just sits there, watches it, and intervenes if things are not going exactly to plan,” Krieger recounted. An example of “not going exactly to plan” might be a difficult-to-navigate corner that the surgeon may decide requires some fine adjustments, he said, “but most of the time, the robot operates autonomously with the surgeon just watching.”
The technology behind STAR has three main components: a smart suturing tool with a rotatable tool tip, imaging suitable to soft tissues, and a control structure that allows the tool to make on-the-fly adjustments to account for tissue undulations that occur in living, breathing patients, while also giving the surgeon the option to intervene as he or she sees fit. Of the three, the most difficult was achieving “excellent, high-resolution, 3-D imaging inside the body with a small camera and also with the constrained movements of the robot,” Krieger said. For this, his group worked with that of optics expert Jin Kang, JHU Jacob Suter Jammer professor of electrical and computer engineering. They came up with a structural light-based D endoscope that uses infrared imaging and a light-reflection technique called fringe-projection imaging, and combined it with an algorithm to track the intricate topography of the soft tissue throughout the procedure.
So far, the research group has shown that STAR not only performs anastomosis successfully in live mammals, but also places stitches with superior consistency in spacing, depth, and placement when compared to manual surgery, Krieger noted. Such consistency is critical in lessening post-surgical complications.
Currently, the JHU group is pursuing human trials of STAR for intestinal anastomosis, while also considering other surgeries that could benefit from similar autonomous capabilities. “One of the things we are most excited about is its value in situations where a surgeon is not present, such as an accidental injury that occurs in a remote (geographical) location,” Krieger said. “Imagine if an emergency vehicle had a little robot that could perform some life-saving procedures on the way to the hospital. That’s the kind of thing we’re looking into right now.”
More and better robots
Khalifa, Webster, and Krieger all said that doctors and patients can expect to see more robotic surgeries in the coming years. Hardware and software upgrades should lead to improved patient outcomes, and as evidence of those improvements mount and patient demand increases, more hospitals will invest in the technology and widen their robotic offerings.
“Robotic surgery is already the norm in certain kinds of procedures, such as prostate removal. In the future, bit-by-bit and surgery-by-surgery, I think we’ll be seeing more and more operations incorporating robots,” Webster said. To get there, progress will be needed not only in specific areas, such as mechanical design, new sensors, software algorithms, and image processing, but in meshing all of those areas so they all work together, he remarked. “Once we do that, the robot will become an active partner, and allow robot-and-human teams to do better than even the best surgeons can do today.”
- Intuitive. (Dec. 14, 2021). Intuitive Reaches 10 Million Procedures Performed Using da Vinci Surgical Systems. Accessed: Oct. 27, 2022. [Online]. Available: https://isrg.intuitive.com/news-releases/news-release-details/intuitive-reaches-10-million-procedures-performed-using-da-vinci
- Vicarious Surgical. Accessed: Oct. 27, 2022. [Online]. Available: https://www.vicarioussurgical.com/
- Virtuoso Surgical. Accessed: Oct. 27, 2022. [Online]. Available: https://virtuososurgical.net/
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- E. Amanov et al., “Transurethral anastomosis after transurethral radical prostatectomy: A phantom study on intraluminal suturing with concentric tube robots,” IEEE Trans. Med. Robot. Bionics, vol. 2, no. 4, pp. 578–581, Nov. 2020.
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