18.11.2014

A cardiac surgical robot is being born at AGH UST


Daniel Prusak from the Department of Robotics and Mechatronics at the Faculty of Mechanical Engineering and Robotics (Photo by Zbigniew Sulima)

Ph.D. Patenting a solution of a laparoscopic end effector powered by a high-precision electric Microdrive (Photo by Daniel Prusak)

The test stand for testing high-precision piezoelectric microdrives (Photo by Mateusz Wójtów)

This is at AGH UST where automated, mechatronic devices which combine mechanics, electronics and control systems come into being. Daniel Prusak, Ph.D., from the Department of Robotics and Mechatronics at the Faculty of Mechanical Engineering and Robotics. Specializes in designing microdevices, micromanipulators and microdrives. Currently, he is working on a cardiac surgical laparoscopic manipulator.

 

This time you have decided to create a robot with a laparoscopic end effector which will be used for cardiac surgeries?

 

That’s right. The research on this kind of device was taken up quite a few years ago and, among other things, the first prototype of a mechatronic laparoscopic end effector, namely a bending wrist, was built. I have designed three types of microdrives, which are critical to the proper functioning of the entire device. What still has to be done is to make the mechanical part consisting of a robotic arm and user interface. Constructing the first prototypes involves not only intellectual but also financial effort. If the new perspective of Union funding is favourable towards medical issues and grants allotted to open calls promote innovative technologies in the field of medicine, a usable prototype can be made quite soon.

 

And this is only the starting point?

 

Certainly. Once the prototype is ready, there is a whole series of experimental and clinical tests. Then it is followed by its certification, that is qualifying the device for medical applications, which also entails costs. Only when the whole procedure, usually taking a number of years, is successfully concluded, the robot will be released for production. We are just at the outset, but if we had unlimited funding, we would be able to build the robot and obtain the certificate in three years’ time. With financial constraints, this time may be doubled or even tripled.

 

Let’s go back to the intellectual effort. What challenges have you had to face?

 

Constructing a laparoscope which works on a micro scale, has a diameter of from 8 up to a maximum of 10 mm and is extremely strong and precise is a great challenge. You need to find solutions to problems relating to functionality, reliability, the most appropriate drive, an integrated control system, and other matters. If someone is able to build a device, particularly a robot, which works with high precision, we say that they deal with micro robotics, as this scientific discipline focusses on constructing devices capable of positioning with a precision of a few nanometers. To guarantee such precision, all phenomena which may adversely influence the precision of a device have to be eliminated. In the case of medical manipulators it is absolutely critical. These phenomena include, for example, friction or play and that is why in micro robotics we don’t use bearings, which are classical motion transfer devices. Here, the drive is constructed in a peculiar way, utilizing piezoelectric and elastic flexure joints. Commonly used drives, like DC motors or stepper motors, do not find their application here. Another issue is the complexity of integrated solutions. In conventional devices the casing can be separated from the drive while in microdevices the systems are interconnected, so the casing becomes the load-bearing frame or even an element of the propulsion engine. The components working inside are integrated and optimized to such an extent that they allow to construct miniature and extremely precise components dedicated for very specific applications.

 

Is your robot capable of carrying out different operations?

 

So far the approach has been to produce robots dedicated to a given type of operations, but, as far as their versatility is concerned, everything depends on the mechanical design and end effectors used. A general tendency is to achieve the highest possible specialization of robots; on the other hand, the medical world expects robots to have the broadest possible scope of applications, putting emphasis on the versatility of the device. I think that constructing a good device with reference to the technological standards and programming it might enable to use it for all kinds of non-invasive surgical procedures. In practice, it would mean proper adjustment of the robot program and exchanging its end effectors. Anyway, training for personnel will be a must. As with any other device, robotic systems require operators to learn how to use them and also what their potential is. We are doing our best to get feedback from representatives of the medical profession, in this way determining the scope of potential applications for new technologies.

 

Are doctors interested in the robot?

 

We often communicate with hospitals and doctors. They need automation and want to employ robots in the operating theatre; they are not afraid of new technologies in medicine. They want to streamline and improve their procedures. It is quite natural since each of us aims at improvement when working with particular devices. But medicine is a specific discipline, because human life is in focus here. Higher quality, improving safety and shortening the period of recovery are the issues worth struggling for. Answering this question we have to return to the financial aspect of this undertaking, because there is interest, but it’s really hard to say if the robot will be used in hospitals. What really matters is the final price of the robot, simplicity of operating it and versatility of its applications. Another vital issue is if the government will be interested in subsidizing hospitals so as to enable them to purchase state-of-the-art equipment like this.

 

Can it be imagined that, having such precise equipment at our disposal, we will no longer need doctors in the operating theatre?

 

This is not possible as man will always have to take responsibility for patients’ health and procedures performed during a surgery. Automated surgeries are carried out under the control of a surgeon who takes full responsibility for all the functioning of a machine. However, it can be imagined that there will be no surgeon in the operating theatre as he or she is, for example, on another continent. Such experiments have already taken place, which proves a high potential of telemedical solutions.

 

If so, what changes in the operating theatre can be brought about by robots?

 

There is an operating table on which a patient lies, but there are no doctors at the bedside, only robots. Surgeons are at a distance and control operations performed inside the patient’s body by means of robots. Thanks to robots we are able to reach the places where it is impossible to get during a manual surgery and minimally-invasive operations can be carried out, as well. In practical terms, it is possible to operate on a patient’s heart through three tiny incisions in their body. This is an enormous technological breakthrough. Automating surgeries, that is a situation where most of the surgical operations are performed by robots, has the advantage of eliminating medical errors and achieving higher precision of operations. Machines are designed in a way allowing for the elimination of mistakes committed by doctors, resulting, for example, from tremors in the hands, for the automation of certain activities, like suturing, for better visualization, that is having a 3D insight into a patient’s body and also for a reduction in the number of postoperative complications, which shortens the period of rehabilitation. At present increasingly more intense research work on the so-called feedback effect is ongoing. In practice it is the effect where through a robot’s arms it will be possible to perceive the same loads and reactions as those experienced when traditional surgical instruments are used. Robot-assisted surgical operations are safer for patients, more reliable and repeatable, but they are still far more expensive than conventional ones.

 

Is it possible that the introduction of robots will ultimately shorten long queues of patients waiting for medical advice and to be operated on?

 

It’s hard to say because automation in medicine has a number of levels. As regards cardiac surgical medical robots, each operation has to be supervised by a surgeon in charge. It’s impossible to determine how many more operations will a surgeon be able to perform, but, undoubtedly, this number will be higher than when he or she stands at the surgical table and uses traditional surgical instruments, which is extremely exhausting. Manipulating a robot can be compared to operating a computer. A surgeon who uses a robot does not suffer from physical fatigue. Of course, being responsible for the success of a surgical operation they might still be mentally and emotionally exhausted, but to a lesser degree, because, as I have mentioned before, they don’t have to worry about the precision of their movements, since the robot will strictly follow the instructions of the selected program, its arms do not tremble and a random displacement is impossible, however small. What is an extremely important aspect is not reducing queues, but shortening the period of postoperative rehabilitation, since with robot-assisted surgeries, patients are ready to return home after a few days. It will shorten the period of recovery and reduce the number of complications. This is not only the case of cardiac surgical operations but also of urological operations which utilize the same type of robots. Lower incidence of postoperative complications entails lower costs. That’s why operating theatres and rehabilitation rooms will see increased volumes of patients, who will recover significantly faster. Thanks to this the queues will also be reduced.

 

In the Department of Mechatronics, a number of projects dealing with robotic design are being developed. These are: a urologic robot, a robot for mixing anti-cancer drugs (cytostatics), and a biological manipulator. All these projects focus on automating and fastening well-known procedures. In the case of the mixing robot the result will also be an increase both patients’ and personnels’ safety.

 

Operating theatres in other countries are already equipped with robots. How will your device differ from them?

 

A laparoscope is instantly associated with a minimally-invasive operation carried out with a device powered by means of wrapping connectors with one or two degrees of freedom, which is manipulated manually by a surgeon. A medical robot means a massive technological jump in itself. The most famous cardiac surgical robot in the world is da Vinci, whose drives utilize wrapping connectors. My solution of a laparoscopic end effector is based on specially–designed electric microengines and I can honestly say that it is one of the most innovative solutions in this field; it is subject to patent protection. Still, it is an element of a larger whole. If we obtain appropriate financing and the research work proceeds in this direction, we can easily build a fully functional cardiac surgical robot. I hope this project will be developed on a large scale and with the implementation of a wide range of technological innovations.

 

An interview by Ilona Trębacz