The demands of modern society and the current threats of pandemics require fundamentally new treatment technologies. The use of robots in medicine - robotic surgery - is the direction that provides such technology. Robot surgery as a new trend in surgery, proven highly medically effective, is being actively developed and implemented in clinics worldwide. Many countries have state programs stimulating the introduction of robot surgery, special institutes and development centers are being established, and international cooperation is being formed. Although the introduction of this technology into medicine has been slower than in other fields, the impact can be enormous: robotics in therapy can help reduce human errors, shorten recovery times and reduce hospital stays, ultimately improving patients' quality of life.
Robot surgery: essence, significant advances, and benefits
Robot surgery - moving to the next level in operations based on new principles of remote interaction between the surgeon and the patient and new robotic surgical technologies.
Technological advances in robot surgery in recent years:
- performing surgery at a distance from the surgical table by a surgeon sitting in a comfortable posture that allows him to be less tired and, as a result, more focused and attentive,
- overcoming the barrier caused by the physiological abilities of the surgeon's hands: robotic surgery can remove tremors and improve hand accuracy,
- the 3B camera allows the surgeon to isolate and view as small a surgical field as possible, thereby opening up the possibility of practical work with small organs, vessels, nerve endings, etc. Robotic surgery has been accepted by the global surgical community and is actively developing. In addition to these advances, the introduction of robotic surgery offers significant benefits at all levels of surgical care organizations. For the patient:
- Minimal trauma to organs and skin during surgery,
- Low probability of complications after surgery,
- minimal blood loss,
- Preservation of nerve bundles, large vessels, separate organs,
- Preservation of vital functions, which was impossible before,
- minimal time spent in the clinic and a quick recovery. For the surgeon:
- The precision of operating a surgical instrument - previously unavailable, down to the size of cells,
- the use of microinstruments,
- easy access to the operating field. For the clinic:
- Reduced postoperative complications,
- Reducing the length of a patient's stay in the clinic, increasing bed turnover,
- implementation of digital technologies, increasing the prestige and attractiveness of the clinic, increasing the influx of patients. For the state:
- Development of new digital technologies in healthcare, including artificial intelligence,
- Significant savings and optimization of the use of beds,
- implementation of the most advanced and efficient technologies for patient care.
Iron surgeons
Most robotic surgeons are not robots in the classic sense of the word. They are not independent and act according to commands, repeating human movements. That said, surgical robotics began specifically with programmable machines and only then changed direction.
From history
In 1985, a robot was used for the first time when a 52-year-old man was manipulated in a CT scanner to open his skull and take a tissue sample. In this operation, the surgeons were assisted by a PUMA 200 arm built for use on General Motors assembly lines. The industrial component was needed to accurately position and hold the guide tube through which the needle was inserted. The operation ended safely, but the robot's manufacturer banned the use of PUMA in surgery. It may have been due to reputational and legal risks.
ROBODOC
The very next year, veterinarian Howard "Hap" A. Paul and engineer William Bargar, along with specialists from IBM, launched the development of a robot for the joint endoprosthesis. In the past, implants were placed using acrylic cement. But this material deteriorated over time, and patients had to go under the knife again. In the mid-1980s, an alternative appeared - porous implants. The bone fuses with them, and the new joint serves for decades. The longer, the smaller the gap and the more precise the insertion. To make notches in the bone for implant placement, Paul and Bargar invented ROBODOC, after Robocop. ROBODOC was first tested on dogs with hip injuries and then on humans under the Food and Drug Administration (FDA) supervision. Structurally, the Robodoc is a SCARA 5-axis arm with a cutting head, a 6-axis pressure sensor, and a water supply system for cooling and dust removal attached to the end of the peninsula. ROBODOC managed to achieve a high precision cut of up to 0.5 mm. As a result, the robot cut only 0.54% more fabric than necessary. It is even though surgeons manually removed about 30% more bone when placing the implant. Despite the positive results, clinical trials were delayed. In 1994, ROBODOC became the first surgical robot allowed on the EU market, but the use of the machine was soon halted due to a series of accidents. Revisions and retesting only ended in 2008. Only then did ROBODOC finally receive FDA approval. It was the only programmable surgical system certified in the United States for an extended period.
Military surgeons
For the first time in the military field of medical robotics, more precisely - the concept of telesurgery interested engineers from the U.S. defense agency DARPA. This idea seemed very promising. Using a robot with remote control, surgeons could operate on the wounded not far from the front lines without being distracted by the bullets whizzing over their heads. DARPA funded telesurgery research for ten years, up until the 1990s. It turned out that with more than 200-300 ms signal delays, surgery becomes difficult, and at 700 ms, very few surgeons can perform their tasks. Then the military decided they could not provide the necessary communication speed and froze the program. One of the followers of DARPA was Yulun Wang, a Ph.D. candidate from the University of California, Santa Barbara. In 1992, he designed AESOP, a robotic laparoscope. Two years later, this device received voice control. Laparoscopic surgeries could now be performed without the assistance of a live assistant, opened Computer Motion, Inc. It is how the first serious player appeared in the surgical robotics market. The FDA approved sales of AESOP in 1994, and in 1995 Computer Motion, a company founded by Wang, began testing ZEUS, a new surgical system. Another follower was MIT student Akhil Madhani, who in 1993, with the help of professor Kenneth Salisbury, assembled the Black Falcon telemanipulator. This design became the basis for the manipulators of the first generation da Vinci robotic surgeon. At first, da Vinci was advertised as a specialized device for delicate cardiac surgery. Still, urologists and gynecologists, who had to work in a cramped and filled pelvic cavity with various organs, became interested in the robot. The FDA then cleared da Vinci for minimally invasive pelvic surgery. Since then, this robotic surgeon has remained the most popular, with several new systems copying its design. As of March 31, 2021, Intuitive Surgical had already installed 6,142 different generations of robots worldwide. The list of procedures in which da Vinci is used is still growing.
Reasons for popularity
The use of the robot contributes to a shorter rehabilitation period and allows patients to go home two days after surgery and almost no scars. By comparison, after conventional surgery, they spent weeks in the hospital before being discharged. Also, when performing surgery without a robot, the surgeon's movements are severely restricted; unable to bring the instrument to the target at an arbitrary angle and has to use additional tools to compensate. The doctor has to observe the procedure with a laparoscopic camera, which means a poor view and a flat, two-dimensional picture. All of this makes relatively simple procedures like suturing and knotting very challenging. Robots can do all the same things, but they are much easier to operate than laparoscopic instruments. The surgeon works with da Vinci manipulators as if his hands were inside the patient. The robot eliminates the point-of-care effect and allows you to use the skills you learn during open surgeries. There are additional benefits. The robot filters the surgeon's movements and reduces instrument jitter even compared to open surgery. In addition, da Vinci scales activities, such as 2 to 1 - turning every two centimeters of movement of the surgeon's arm into one centimeter of motion of the manipulator.
Shortcomings of the da Vinci
In more than 20 years of clinical practice, the da Vinci has earned a reputation as a well-thought-out and safe machine, but the robot is far from perfect. The engineers had to make a lot of compromises in its design.
- Poor precision. You can't control the movements of the arms because the sensors are on the motor side. Also, the cables shift and rub against the polymer shell each time the robot moves. And the smaller the curvature radius of the line, the more friction there is. It's hard to compensate for this programmatically, especially if you're trying to keep the movements smooth. That's why da Vinci can't be an autonomous robotic surgeon. The accuracy of the robot mechanics is about 2 mm, and the error in repeatedly returning the instrument to the same point is about 1 cm. The surgeon constantly monitors this and corrects the movements.
- Working volume and uneven force. Keep in mind that accuracy, like robot force, is not constant. They depend not only on the number of joints and mobility but also on the position of the manipulators in space.
- Limited feedback. Another significant disadvantage is that the robot arms do not provide tactile feedback. During conventional open surgery, the surgeon relies heavily on touch, for example, to distinguish one type of tissue from another or to gently tighten a suture. Da Vinci deprives the surgeon of this sense. This drawback is noted by almost everyone who criticizes the system. The robot can exert more force at one point than at another. The same is valid for positioning accuracy. Some issues are more inaccurate than others.
- Duration of operations. Studies show that robot-assisted surgeries are faster on average than open but longer than conventional laparoscopic surgeries. And as the duration increases, so do the risks - the patient stays longer under general anesthesia, and more carbon dioxide is absorbed into the tissues.
- Cost. Modern robotic surgeons cost about $2 million, but their sales bring the company only over 30 percent of the profit. The rest comes from maintenance and tool supplies. Consumables are costly. For the price of one robotic forceps, you can buy several traditional laparoscopic instruments for hundreds of surgeries. To break even after buying a da Vinci robot, you would need 150 to 300 robotic surgeries each year for six years. Robotic surgery in the U.S. costs $3,000 to $6,000 more than conventional surgery. Therefore, hospital administrators are not interested in letting a robot sit idle. In the U.S., patients are often "pushed" to have robotic surgery, even though conventional ones are cheaper and may be better from a medical point of view.
What is the difficulty in developing robotic surgeons
Many surgeons note a lack of image clarity, meaning a need to upgrade cameras. Moreover, it is believed that much better robotic surgeons can already be created with standard technology. Still, the market is dominated by a system that has not fundamentally changed in 20 years. The main reason is that it is a tough engineering challenge. The ideal surgical robot must be precise, agile, fast, able to make delicate movements, exert great force, and reliably grasp and lift weights. The required characteristics are interrelated, and achieving everything at once is a complex and challenging task. For example, the accuracy of a robot. It depends on various factors. Here's a partial list: arm design and weight, clearances, and play, cable tension, friction, sensor resolution, calculation errors, component quality, and even operating room temperature. And all of these factors interact with each other. Another example is structural rigidity. It increases accuracy but improves the arm's size and weight. It increases inertia, so the robot moves slower and lags behind the surgeon. It is difficult, if not impossible, to make a robot good at everything. Engineers have to maneuver between conflicting requirements, which inevitably leads to compromises. The conditions under which a robotic surgeon works do not make it genuinely autonomous. Inside a living organism, everything deforms and changes shape. Despite the built-in heating, the camera gets dirty and fogs up during surgery. Programming a robotic surgeon is also not an easy task. Complex calculations are behind the apparent ease with which human movements are transmitted to the robot. Above all, they are essential for determining the correct position of the robot. In addition, the speed for each actuator has to be calculated so that the arm does not go beyond a safe trajectory and does not harm the patient. To reduce instrument oscillations, smooth acceleration and deceleration are implemented. A single malfunction in a robotic surgeon can cost a person's life. So the generally accepted golden rule here is that the simpler the design, the better. Engineers are highly overconfident and rarely use promising but untested or immature technology. Robotic surgeons undergo countless tests and trials before operating on humans. The process drags on for years, making development even more difficult and expensive. And if you sell the robots anywhere outside the U.S., you must get permits in each country. It is primarily why 71% of robot sales still occur in the U.S., with only 15% of sales in Europe and 10% in Asia. A significant challenge is proving that the robot is medically beneficial. No one disputes that da Vinci makes surgeons' work more accessible, but it's not a fact that the machine is helpful for the patient. The benefits are not obvious, and there is often no evidence that a robot is better for a particular type of surgery than conventional laparoscopic instruments.
The robotic surgery market: performance, trends, and growth prospects
Despite all the difficulties, the robot surgery market is characterized as a rapidly growing market. Over the last 8 to 10 years, it has been growing at an average of 15-18% per year. The volume of surgeries performed using a surgical robot is increasing by about 18-21% per year. In 2019, approximately 1.2 million robotic surgical procedures were performed worldwide. Over the entire period that robotic surgery was introduced, the numbers were:
- 7,200,000 surgeries were performed using a surgical robot,
- 5,500 da Vinci robots sold.
The prognosis for robotic surgery
- The global installed base of surgical robots will increase by more than 4.5 times in 2030 compared to 2017.
- Surgical growth will be driven by both an increase in the installed base and an increase in utilization - from 200 surgeries per year per robot to 309 surgeries in 2030.
- Expected to perform in 2030. Five million surgeries on 20,000 installed robots correspond to an average of 1 surgery per day per robot.
Prospects for robotic surgery around the world
In all economically advanced countries, there is interest and growth in adopting robotic surgical technologies. More than 80 companies are working in the field of robotic surgery all over the world. Surgical robots are being developed for operations in the abdominal area (including urology and gynecology), skeleton joints, the skeleton, lungs, eye, heart, vessels, brain, and nerve bundles.
Analysis of data by country
Europe, the U.S., and Japan have installed 93% of their robotic systems. Companies spend hundreds of thousands of dollars to develop new surgical robots. The rest of the world's population of 6 billion people is only 7% - that's 400 installed robotic systems. India and China, with a population of 2.7 billion people, account for only 3% - about 170 installed automatic systems.
The future of robotic surgeons
Information technology has accustomed us to regular, almost annual revolutions. In IT, a new idea shoots out, gains popularity, and becomes obsolete within a year. In medicine, it's different. Because of all these complexities, the development and implementation of robotic surgeons require enormous investments, and investments in this field bring results decades later. But no matter what, the surgical robotics market is growing (projected to grow by 13.14% by 2025). Competition is growing, and da Vinci-like robots are emerging—for example, the Korean Revo-i and the Chinese Micro Hand S. At the same time, medicine's conservatism turns out to be an unexpected opportunity. By seeing how engineers mix existing technology, it is possible to anticipate the future of medical robotics.
Promising developments
Flexible manipulators
Surgeons need more flexibility in their arms. It includes more freedom of action and the ability to perform surgery without visible incisions, through natural openings in the body, or by moving to the right point in the body via large vessels. The new da Vinci SP model already boasts multi-articular instruments inserted into the body through a single opening. The Israeli Hominis system recently received FDA approval and is even more flexible. This robotic surgeon's tools bend all 360 degrees, except they don't get tied into knots. There are snake-like robotic endoscopes, like Flex and automated catheters. Not so long ago, they performed a series of operations on pigs using such a device. The catheter reached the heart valve automatically by following the vessel walls and navigating using a hybrid optical touch sensor and machine learning algorithms.
New actuators
In parallel, experiments are underway with new varieties of motors to replace ropes and electric actuators. Everything is being investigated, including pneumatics and hydraulics, but electroactive polymers - artificial muscles - seem to be the most promising for minimally invasive surgery. They are not expensive, highly deformable, don't take up much space, and develop considerable force. But these technologies require high voltages to work. Using a few hundred volts near the patient is dangerous, so these developments are cautiously treated.
Machine Learning
Blockchain has not yet been implemented in surgery, but machine learning is a big part. Here, it can be helpful on several levels at once. Machine learning algorithms can simplify the calculation of manipulator movements or automate entire stages of surgery. For example, in 2020, a team at the University of California, Berkeley, trained a neural network to make perfectly straight stitches with the help of video recordings. Moreover, back in 2016, during the actual surgery, researchers showed that a robotic surgeon could sew together fragments of a pig's intestine on his own. However, the surgeons then pre-marked the surgical area with infrared markers. These guided the robot during the operation. Unfortunately, the features are impractical - they are not easy to implant and challenging to remove. The main problem is to teach robots to use such skills in the changing conditions of the human body. So far, algorithms have been trained to rely on camera data. It is not yet clear whether machine vision algorithms can work inside the body. However, this is not the only way.
Integration with medical scanners
Integrating robots with medical scanners is of great importance in medical robotics: CT, MRI, and ultrasound. There are separate robotic ultrasound systems and sensors designed for installation on da Vinci. Their picture is usually transmitted to a different window in the surgeon's field of vision. Systems for general surgery integrated with CT and MRI are still at the conceptual stage.
Augmented and Virtual Reality
Of all the innovations listed, this is the closest. The introduction of augmented reality into surgery is a matter of the near future. It is a logical development of robotic surgeon interfaces; the only question is what additional information to display in the doctor's field of vision. Moreover, in December 2019, full-fledged virtual reality officially arrived in operating rooms. The FDA has approved surgeries using the Vicarious Surgical robot. This system replicates the human body: head, shoulders, elbows, and wrists. The robot is connected to state-of-the-art virtual reality goggles, so the surgeon is immersed in the head. Thus, there is no doubt that medical robotics will evolve. Several advances in robotics in the medical field can improve the quality of treatment and outcomes for patients. However, several hurdles must be overcome for these technologies to be applied to patient care in the long term. In addition to complex and often costly developments, companies in this field will have to consider factors such as regulatory, pricing, and training of medical professionals, not to mention emotional and ethical considerations in a sensitive area such as medicine. Robotic technology can bring tremendous benefits to health care. Still, there is no consensus on whether all of the problems have been overcome to ensure the long-term practical application of this technology. Robots may never replace surgeons, but that does not matter; what matters is that they will help save real lives shortly.