Customized Operations
Tomorrow's Operating Room – Interviews with Experts
It's been over 100 years since Wilhelm Conrad Röntgen discovered X-rays. The first pictures showing the bone structure of his hand caused a sensation.
An X-ray of W. C. Röntgen's hand, taken in 1896
Since then, imaging technology has advanced by leaps and bounds. Today, ultrasound, computer tomography and magnetic resonance imagery provide data that helps physicians simulate procedures on-screen and plan for optimal surgical intervention. In the modern medical world, patients are no longer treated according to fixed procedures—instead, they receive surgery tailored to their conditions. Sophisticated navigation instruments and robots also allow surgeons to position equipment in the body with pinpoint accuracy.
"Pictures of the Future" talked with three top experts in surgery and asked them how they plan and conduct operations today and how tomorrow's operating room might look. The interviews were conducted by Ulrike Zechbauer.
"To operate successfully, we have to retrace the steps made during computer simulation"
Interview with Axel Perneczky
Professor Axel Perneczky, 55, is director of the Neurosurgical Clinic and Polyclinic at the Johannes Gutenberg Univer-sity in Mainz. In 1993, he founded the German Society for Endoscopic Neurosurgery and Neuronavigation, as well as the international journal "Minimally Invasive Neurosurgery"
In your field—neurosurgery—how do you expect the operating room to change in the future?
Prof. Axel Perneczky: In the future, what we call "intra-operative" imaging will play a big role in neurosurgical operating rooms. That's the kind of imaging that surgeons use during an operation to navigate instruments and endoscopes to the right position. Intra-operative techniques will involve imaging systems such as ultrasound, computer tomography (CT), magnetic resonance tomography (MR) and angiography. Today, if a surgeon needs an intra-operative MR or CT, the patient generally has to be taken from the operating room to another room. Given the complexity and danger associated with moving a patient at this stage, doctors sometimes decide to do without the images. The operating room of the future, however, will house all the imaging equipment required—so that it comes to the patient and not vice versa. In fact, the first steps in this direction have already been taken. In our operating room, for example, we've been using a transportable CT machine for more than three years now. However, if we really want to make use of all the technology that's available, we're going to have to make space for it. In other words, operating rooms will have to become much bigger. Let me emphasize that I'm talking about neurosurgery here. Another thing we're going to require is appropriately specialized technical staff in the operating room. Today, we already need one technical expert for every neurosurgical operating room. In addition, the clinic employs information technology specialists who are responsible for supervising and developing our own in-house computer, documentation and navigation systems.
How important is advance planning for a neurosurgical operation?
Perneczky: It's very important. In much of surgery, the conventional strategy is to open up the problem area and take a look at the precise pathological situation. That's not really an option in neurosurgery. Even the smallest injury to vessels supplying nerves or brain tissue can have serious consequences for the patient. As there's no free space inside the head, we have to create a corridor between healthy structures to the target area. To reduce the impact on healthy structures as much as possible, we have to minimize intervention and draw up an exact geometric plan for every operation. Fortunately, we have access to excellent imaging diagnostics and can therefore familiarize ourselves in advance with the individual patient's anatomy before surgery.
Is it now possible to conduct a virtual examination of the brain prior to an operation?
Perneczky: Yes it is. With the kind of resolution on offer from today's imaging techniques, it's possible to detect very fine structures and even simulate a journey through the body. Using CT data and special software, for example, neuroradiologists from our clinic have been able to conduct a virtual endoscopy of the inner ear. MR imaging provides just the kind of data we need to make such a simulated trip through the brain. Each morning before the day's operations, we discuss the patients' image data with colleagues from the Institute of Neuroradiology. Specially developed computer programs convert these images into 3D models, which help us evaluate the area under investigation. With these models, we can also try out different approaches and thereby determine the best operating strategy. The next phase is to implement this individual plan—in other words, we have to follow the steps we made during computer simulation. And there's no room for the odd "tweak" here and there—the entire procedure must run perfectly. This is where the navigation of surgical instruments and endoscopes comes in—a technology we're working hard to advance at our clinic.
How does neuronavigation work?
Perneczky: First of all, the complete anatomical structure of the head is mapped out in a three-dimensional coordinate system. The calculations to determine the coordinates of each point in the head are based on data from MR and CT images. In the past, we also used radiographic techniques in which images are created by injecting a contrast medium opaque to X-rays. The calculated coordinates are translated onto the patient's anatomy using a special kind of frame fixed to the patient's head. This so-called stereotaxis is a traditional neurosurgical technique. With the help of computers, the various images are now used to plan the actual intervention. Once in the operating room, the navigation system is linked to special instruments. In this way, the surgeon can observe on-screen the position of an endoscope or a probe not only spatially, but also in relation to the patient's anatomy. That's essentially what we mean by neuronavigation.
Given that the area undergoing surgery is incredibly narrow, you've developed a special helmet incorporating a video system that shows the surgeon images from inside the patient. How long have you been using such helmets?
Computer-based preoperative planning showing fused, 3D CT and MR images of a cranium. With the aid of a special pen, physicians are able to define and move various cross-sections. This provides valuable insight into the state of the tissue at each location. CT data (yellow) shows bones; MR data (red-violet) shows blood vessels with blue-green area indicating tumor
Perneczky: We started developing them seven years ago and we've been routinely using them for three years now. The helmets incorporate twin video monitors—one for each eye. Originally, the monitors were only connected to the signal from the endoscopic camera. At a later stage of development, however, the system also began to incorporate other visual information. Today, for example, the helmets show images from the surgical microscope camera as well as navigational data from CT, MR and digital angiography equipment. Surgeons use a voice-activated control system to select whatever images they need. It's also an excellent teaching aid, since you can connect as many helmets to the video system as you want. Everyone then sees the same 3D images being used by the surgeon and can thus follow every step of the procedure.
An important trend in medicine is minimally invasive surgery. What is this exactly?
Perneczky: The aim of minimally invasive surgery is to damage as little healthy tissue as possible while achieving maximum therapeutic effect. The popular view that any surgery is minimally invasive just as long as the incisions involved are small is not quite correct. There are situations when a surgeon has to create a large opening in order to treat a patient. In other words, the smallest possible incision can in some cases be 10 cm in length. The aim must always be to achieve the maximum therapeutic effect while minimizing the trauma every operation entails. In addition to surgical considerations, things like cosmetic aspects also have a role to play. For example, scars should be as nearly invisible as possible. It's also important to avoid shaving large parts of a patient's head, so that he or she feels confident about meeting people after the operation. "Optimally invasive" rather than "minimally invasive" therefore better describes what we're trying to achieve.
Turning to the subject of telemedicine, could you imagine a situation in the future in which a cardiac surgeon in one city operates on a patient in another?
Using a video helmet outfitted with twin monitors, surgeons can see 3D images of regions inside the patient's body. A voice-activated control system allows them to choose CT, MR, endoscopic or microscopic images
Perneczky: From a purely technical point of view, I can easily imagine it, provided that both places are equipped with the same systems. However, I see an ethical problem here. In my opinion, the senior surgeon must be present in the operating room. The human body is always good for a surprise or two. In any operation, unforeseen problems can arise that need to be solved immediately and on the spot. In such a case, a telesurgeon hundreds or thousands of kilometers away wouldn't be able to take appropriate action and would therefore have to rely on the skills of the team in the operating room. But if the surgeons there are just as capable of performing the operation, why bother with the telesurgeon in the first place? Moreover, I don't believe that each operation calls for a specialist,. That's like saying the surgeons at the clinic can't cope with the operation.
Do you see better prospects for the area of teleconsultation, where a physician in one place would advise a colleague in another either during an operation or during the preoperative planning phase?
Perneczky: From a technical point of view, I find the idea interesting. But from a medical one, I think that teleconsultation would be every bit as awful as what we've just discussed. Just imagine that a patient being operated on has just put his or her trust in the surgeon and the operating team, when suddenly another doctor, who is following the operation via a video link, says: "Stop! You shouldn't be doing that." And the surgeons back in the operating room reply: "Okay, you're the expert. Tell us what you want, and we'll do it your way." Should something go wrong, the responsibility always lies with the person operating. There's no way that he or she can wriggle out of this at a later time. I find it highly dubious that a surgeon should suddenly alter something during an operation and then be able to say afterwards: "But it wasn't my idea." The potential advantages of teleconsultation in preoperative planning are also overrated. If it's a simple question, you don't need a second opinion. And if it's a complicated one, you end up with as many different answers as the number of people you have asked.
"Medical robots are a technical aid. But they cannot replace the surgeon"
Interview with Martin Börner
Prof. Martin Börner, 57, has been medical director of the Berufsgenossenschaftliche Unfallklinik in Frankfurt am Main since 1990. A pioneer in the use of robotics in surgery, he became the first surgeon in Europe to employ the technology known as Robodoc seven years ago
Back in 1994, your clinic became the first in the world to begin routinely implanting artificial hip joints using robots. How many operations have you conducted with the Robodoc system and what are the advantages of this treatment?
Prof. Martin Börner: Altogether, we've carried out 4,000 hip-replacement operations using Robodoc. Since March 2000, we've also implanted around 300 artificial knee joints using robot technology. The biggest advantage of this method is that it enables us to plan an operation using a 3D model and then implement our plan with the highest precision. Working on the basis of patient CT images generated before the operation, we can select a virtual joint from our prosthesis catalog and place it in exactly the right position on the computer screen. This can be done to a precision of 0.1 mm in any direction and within an angle of 0.1 °. Next, the CT data and other planning information are fed into Robodoc. During the operation, the robot is able to mill away the thighbone by exactly the right amount, thereby ensuring a perfect fit for the replacement joint. And since the prosthesis fits perfectly and is exactly aligned with the axis of the bone, the patient is able to put a full load on the new hip right from the start. The figures paint an even clearer picture: With the robot, the degree of surface contact between bone and the artificial joint is as high as 95 to 98 %, whereas even a highly experienced surgeon working by hand will only achieve somewhere between 30 and 35 %.
Do patients trust medical robots?
Börner: Absolutely. Robodoc enjoys higher acceptance among patients than among doctors. Patients also have higher expectations regarding the technology. In fact, it's ultimately due to patients that the method has made such rapid progress. Some physicians are afraid that the robots could end up taking their jobs. But that's nonsense. In the run-up to a hip operation involving a robot, for example, the surgeon actually spends more time with the patient than is the case with conventional hip-replacement surgery. Every intervention on the part of the robot must be precisely planned. By contrast, an anonymous survey of hip-replacement surgeons revealed that only 45 % of conventional operations actually involve any preoperative planning.
What other procedures could be performed by robots in tomorrow's OR?
Börner: A voice-activated robot that hands me surgical instruments during an operation would be very useful. After all, removing pins and metal plates from specific bones always calls for the same range of instruments. Before an operation, the nurse would prepare everything and put the instruments in a particular place. Once in the operating room, the surgeon would request, say, a hex wrench, and the robot would hand it over. At present, the image converter used to observe the patient during an operation is run by a member of the operating room team. In the future, it could be mounted on a robot-controlled platform that responds to voice commands. The crucial thing about any development in medical technology is to ensure that physicians work closely with technicians, engineers and IT experts. Collaboration is the key to creating the kind of new technologies that genuinely boost the quality of healthcare. In the future, we will see more medical technology experts focusing on surgery. This relatively new field has a promising future.
With the help of sterile robots, artificial knee joints can be precisely implanted
Will the nature of medical training also have to change?
Börner: Yes, but there's a danger here that interns will no longer learn the basics and will instead rely on technology. The trouble is that when the technology fails, they'll have big problems turning to conventional methods. The solution here is to come up with a training compromise that takes equal account of the classical elements of surgical techniques, on the one hand, and technical know-how, on the other. I believe the practice of "learning by doing" on patients will become less and less important. Instead, interns will focus more on individual preoperative planning and will use special simulators to practice operations over and over again. To that extent, they'll be like airline pilots, who have to spend a long time practicing on a flight simulator before they actually see the inside of a cockpit.
Will future medical robots perform operations on their own?
Börner: No. I believe that a surgeon will always be present during each stage of an operation and will order each action that a robot takes. Medical robots are a technical aid. They do not replace anyone. Instead, their function is to provide support in the operating room. The sole aim of such technology must always be to boost healthcare quality and improve patient well-being.
"By the year 2015, most dentist offices will have a robot system for implants"
Interview with Tim Lüth
In 1997, Professor Tim Lüth, 35, was appointed director of the Surgical Robotics Lab and Professor of Robotics and Navigation at the Charitè Medical Faculty of Humboldt University in Berlin. Just two years later, Lüth, an electronics and information technology specialist, received the prestigious Alfried Krupp Award for young academics, which is endowed with 500,000 €. At present, he is the only professor of medical robotics in Germany; in total, there are only three professorships in this field worldwide
Operating room robots are becoming more and more popular. How many of them are now in clinical use?
Prof. Tim Lüth: Not very many. At present, only some 200 machines worldwide are used in operations involving people. This includes robots used in orthopedic surgery that mill bone as well as the interactive, robot-based equipment used to guide instruments in neurosurgery. In addition, some 600 camera-guidance systems are used in minimally invasive surgery. Of the few research institutes currently working on the development of medical robots, most are located in Germany and the United States.
In March of last year, physicians at Berlin's Charité Hospital became the first in the world to use medical robots in a facial operation. With the help of the new technology, they were able to fit an artificial ear with extraordinary precision. The robot used costs about 500,000 € and was developed by you. What advantages does it offer?
Lüth: Just imagine that you want to hang a picture on the wall. First of all, you mark two holes and then reach for the drill. Afterwards, however, you realize that you've drilled in the wrong place and the picture is lop-sided. Things are similar in facial surgery. Fitting artificial facial elements involves screwing small titanium pegs into the patient's skull or jawbone. If the surgeon bores out the thread of the screw by hand, it's impossible to say in advance exactly how the peg will sit in the bone afterwards. That's why physicians generally first measure the position of the titanium pegs once all the bore wounds have fully healed and then order a facial prosthesis to fit. As a result, patients often have to wait for weeks to have, say, an artificial ear fitted. On the other hand, our intelligent robot—we call him "Otto von der Decke" (Otto from the ceiling)—can calculate the exact position of the bore holes in 3D and at an accuracy of 0.2 mm. It can control the drilling operation so precisely that we can be almost 100 % certain that a prefabricated prosthesis will fit perfectly. A patient can therefore be fitted with an incredibly lifelike silicon ear on the day of the operation. "Otto" is the only facial surgery robot in the world to have been approved in line with legislation governing medical products.
Given such impressive results, do you think that robots may one day replace surgeons?
Lüth: No, I think that's completely utopian. The surgeon is irreplaceable and will remain so. Even in the future, we're not going to see robots operating autonomously. Instead, they'll continue to support surgeons and will help improve the quality of medical care.
This spider-like creation is a robot known as "Otto von der Decke." It can drill holes for facial prostheses to an accuracy of 0.2 mm
At the end of 2001, you're going to start marketing a robot system for dental implants. Will dentists be able to afford RoboDent?
Lüth: Larger dental practices will certainly be able to afford it. RoboDent will approximately cost 50,000 €— this is one-tenth of what you would have to pay for Otto von der Decke. Some patients spend more than 50,000 € on dental implants, so it's only natural that they expect top quality. RoboDent is destined, in my opinion, to play an important role in the dentistry by guaranteeing that dental implants fit perfectly. The system has already been approved throughout Europe and procedures are also under way to obtain approval for its future use in the United States as well.
What does the RoboDent system actually consist of?
Lüth: RoboDent is made up of a standard PC, a small monitor, planning software and a special infrared sensor capable of measuring the alignment of the drill in the patient's mouth to an accuracy of a few tenths of a millimeter. Using the PC, the dentist is able to precisely plan the implant. During the actual operation, this knowledge results in an accuracy of 0.5 mm. This is because the dentist is able to work with both hands free and with great precision. On a monitor located right next to the patient's open mouth, the system shows a 3D image of exactly where the drill must be positioned. In this way, the dentist can fix the titanium pegs so that they are exactly parallel to one another and, in turn, can mount the new implants so that they fit perfectly. As a result, the patient leaves the dentist's office with a new set of teeth capable of handling any kind of food within a week. What's more, the system is so simple that dentists can learn to use RoboDent in just five minutes.
Will drills fitted with navigation systems be standard equipment in dentist offices in 15 years?
Lüth: I think that the majority of them will have this kind of system by 2015. In fact, our estimates suggest that 100 RoboDents will be in operation by the middle of next year. And once a technology has proved itself, it tends to catch on quite quickly.