It is shown that although the potential effectiveness of robotic rehabilitation technology is endorsed by official organizations, there are still conflicting clinical studies with contradictory conclusions. Reasons for these contradictions are discussed in the paper. Two major challenges are identified in this regard, namely conservative patient-robot interaction stabilizing algorithms, and insufficient adaptability of the control parameters to the needs and biomechanics of the patient.
Neural Engineering
How does the brain instruct us to breathe ten times per minute? What controls this respiratory rhythm? How do neurons communicate and coordinate their activity? Understanding how the brain functions from a quantitative point-of-view is the domain of the neural engineer (a.k.a. neuroengineer).
Neural engineers are interested in understanding, interfacing with and manipulating the nervous system. Computational neuroscientists are creating computer models of neural systems down to the level of single neurons. Scientists are also exploring how neurons communicate with one another by taking recordings from actual neurons and having those recordings “interact” with recordings from other neurons. Using quantitative techniques, the nature of these communications are being measured and analyzed. One benefit of understanding this communication is to provide new ways to interface between neural tissue and manmade technologies. This is known as brain-machine interfacing.
Disrupting Neurocircuitry
By understanding how neurons work, biomedical engineers specializing in neural engineering can look for ways to either stimulate or disrupt this neurocircuitry. Implantable devices similar to the pacemakers used in the cardiac setting (see Cardiopulmonary Systems Engineering) could be used to control nervous system disorders such as Parkinson’s disease, depression and epilepsy. monitors and interrupts abnormal electrical activity in the brain before seizures occur.
If we think of nerves as wires, these wires—or neurocircuits—can either be stimulated or blocked. In the not-too-distant future, high frequency electrical stimulation could be used on peripheral nerves in the arms and legs to selectively block some communication—pain, for example—without interfering with other communication. The ability to give highly localized and reversible anesthesia would be one application of this technology. Another is bladder control. Most bladder control problems are actually the result of the inability to control the neurons that indicate to a person whether they need to urinate. High frequency electrical stimulation via an external device could be used to help coordinate activities that the body can no longer control; especially useful for those who are paralyzed.
Visual Prostheses
An artificial retina could soon become reality as many groups are developing devices to replace damaged retinas. A consortium of researchers in Australia, for example, are working on bionic vision technologies to restore sight to people with degenerative vision loss due to either retinitis pigmentosa or age-related macular degeneration. In both conditions, there is a problem in the part of the eye that senses light but the neural circuitry and visual processing ability of the brain is still intact.
Using a camera attached to a pair of glasses, signals are transmitted to a microchip implanted in the retina. From here, small electrical currents are sent to surviving neurons in the brain. Current technology limits the number of implanted electrodes to about 100, so the resolution captured by the camera is processed and reduced to create rudimentary images. But these images can make a world of difference to someone who otherwise cannot see.
The Australian technology will not be tested in humans until at least 2013 and would take several more years before it reaches the market. Second Sight in California is currently in clinical trials on a similar retinal prosthesis system that offers 60 electrodes. And a German consortium has taken a different approach that offers more electrodes, but they are not encapsulated and, therefore, not long-lasting. The German solution is also being tested in humans.
Some of the research in neural engineering sounds like science fiction but is actually science fact. We have seen a robot controlled via cultured neurons in a dish; a fish wired to electrodes dictating the movements of a robot and a remote-controlled rat turning left or right with the press of a button.
Neural engineering incorporates a diverse array of disciplines, including neuroscience, mathematics, engineering, biophysics, computer science and psychology. This important work is providing new insights into our understanding of dementia, Parkinson’s, brain injury, strokes and other neurologic deficits.
Robotic Surgery
Surgical robotics is a new technology that holds significant promise. Robotic surgery is often heralded as the new revolution, and it is one of the most talked about subjects in surgery today. Up to this point in time, however, the drive to develop and obtain robotic devices has been largely driven by the market. There is no doubt that they will become an important tool in the surgical armamentarium, but the extent of their use is still evolving.
Several centers are currently using surgical robots and publishing data. Most of these early studies report that robotic surgery is feasible. There is, however, a paucity of data regarding costs and benefits of robotics versus conventional techniques.
Robotic surgery is a new and exciting emerging technology that is taking the surgical profession by storm. Up to this point, however, the race to acquire and incorporate this emerging technology has primarily been driven by the market. In addition, surgical robots have become the entry fee for centers wanting to be known for excellence in minimally invasive surgery despite the current lack of practical applications. Therefore, robotic devices seem to have more of a marketing role than a practical role. Whether or not robotic devices will grow into a more practical role remains to be seen.
Our goal in writing this review is to provide an objective evaluation of this technology and to touch on some of the subjects that manufacturers of robots do not readily disclose. In this article we discuss the development and evolution of robotic surgery, review current robotic systems, review the current data, discuss the current role of robotics in surgery, and finally we discuss the possible roles of robotic surgery in the future.
CURRENT ROBOTIC SURGICAL SYSTEMS
Today, many robots and robot enhancements are being researched and developed. Schurr et al at Eberhard Karls University’s section for minimally invasive surgery have developed a master-slave manipulator system that they call ARTEMIS.13 This system consists of 2 robotic arms that are controlled by a surgeon at a control console. Dario et al at the MiTech laboratory of Scuola Superiore Sant’Anna in Italy have developed a prototype miniature robotic system for computer-enhanced colonoscopy.14 This system provides the same functions as conventional colonoscopy systems but it does so with an inchworm-like locomotion using vacuum suction. By allowing the endoscopist to teleoperate or directly supervise this endoscope and with the functional integration of endoscopic tools, they believe this system is not only feasible but may expand the applications of endoluminal diagnosis and surgery. Several other laboratories, including the authors’, are designing and developing systems and models for reality-based haptic feedback in minimally invasive surgery and also combining visual servoing with haptic feedback for robot-assisted surgery.15–19
In addition to Prodoc, ROBODOC and the systems mentioned above several other robotic systems have been commercially developed and approved by the FDA for general surgical use. These include the AESOP system (Computer Motion Inc., Santa Barbara, CA), a voice-activated robotic endoscope, and the comprehensive master-slave surgical robotic systems, Da Vinci (Intuitive Surgical Inc., Mountain View, CA) and Zeus (Computer Motion Inc., Santa Barbara, CA).
The da Vinci and Zeus systems are similar in their capabilities but different in their approaches to robotic surgery. Both systems are comprehensive master-slave surgical robots with multiple arms operated remotely from a console with video assisted visualization and computer enhancement. In the da Vinci system (Fig. 1), which evolved from the telepresence machines developed for NASA and the US Army, there are essentially 3 components: a vision cart that holds a dual light source and dual 3-chip cameras, a master console where the operating surgeon sits, and a moveable cart, where 2 instrument arms and the camera arm are mounted.1 The camera arm contains dual cameras and the image generated is 3-dimensional. The master console consists of an image processing computer that generates a true 3-dimensional image with depth of field; the view port where the surgeon views the image; foot pedals to control electrocautery, camera focus, instrument/camera arm clutches, and master control grips that drive the servant robotic arms at the patient’s side.6 The instruments are cable driven and provide 7 degrees of freedom. This system displays its 3-dimensional image above the hands of the surgeon so that it gives the surgeon the illusion that the tips of the instruments are an extension of the control grips, thus giving the impression of being at the surgical site.
PRACTICAL USES OF SURGICAL ROBOTS TODAY
In today’s competitive healthcare market, many organizations are interested in making themselves “cutting-edge” institutions with the most advanced technological equipment and the very newest treatment and testing modalities. Doing so allows them to capture more of the healthcare market. Acquiring a surgical robot is in essence the entry fee into marketing an institution’s surgical specialties as “the most advanced.” It is not uncommon, for example, to see a photo of a surgical robot on the cover of a hospital’s marketing brochure and yet see no word mentioning robotic surgery inside.
As far as ideas and science, surgical robotics is a deep, fertile soil. It may come to pass that robotic systems are used very little but the technology they are generating and the advances in ancillary products will continue. Already, the development of robotics is spurring interest in new tissue anastomosis techniques, improving laparoscopic instruments, and digital integration of already existing technologies.
As mentioned previously, applications of robotic surgery are expanding rapidly into many different surgical disciplines. The cost of procuring one of these systems remains high, however, making it unlikely that an institution will acquire more than one or two. This low number of machines and the low number of surgeons trained to use them makes incorporation of robotics in routine surgeries rare. Whether this changes with the passing of time remains to be seen.
THE FUTURE OF ROBOTIC SURGERY
Robotic surgery is in its infancy. Many obstacles and disadvantages will be resolved in time and no doubt many other questions will arise. Many question have yet to be asked; questions such as malpractice liability, credentialing, training requirements, and interstate licensing for tele-surgeons, to name just a few.
Many of current advantages in robotic assisted surgery ensure its continued development and expansion. For example, the sophistication of the controls and the multiple degrees of freedom afforded by the Zeus and da Vinci systems allow increased mobility and no tremor without comprising the visual field to make micro anastomosis possible. Many have made the observation that robotic systems are information systems and as such they have the ability to interface and integrate many of the technologies being developed for and currently used in the operating room.9 One exciting possibility is expanding the use of preoperative (computed tomography or magnetic resonance) and intraoperative video image fusion to better guide the surgeon in dissection and identifying pathology. These data may also be used to rehearse complex procedures before they are undertaken. The nature of robotic systems also makes the possibility of long-distance intraoperative consultation or guidance possible and it may provide new opportunities for teaching and assessment of new surgeons through mentoring and simulation. Computer Motion, the makers of the Zeus robotic surgical system, is already marketing a device called SOCRATES that allows surgeons at remote sites to connect to an operating room and share video and audio, to use a “telestrator” to highlight anatomy, and to control the AESOP endoscopic camera.
Technically, much remains to be done before robotic surgery’s full potential can be realized. Although these systems have greatly improved dexterity, they have yet to develop the full potential in instrumentation or to incorporate the full range of sensory input. More standard mechanical tools and more energy directed tools need to be developed. Some authors also believe that robotic surgery can be extended into the realm of advanced diagnostic testing with the development and use of ultrasonography, near infrared, and confocal microscopy equipment.10
Much like the robots in popular culture, the future of robotics in surgery is limited only by imagination. Many future “advancements” are already being researched. Some laboratories, including the authors’ laboratory, are currently working on systems to relay touch sensation from robotic instruments back to the surgeon.15–19,32 Other laboratories are working on improving current methods and developing new devices for suture-less anastomoses.33–35 When most people think about robotics, they think about automation. The possibility of automating some tasks is both exciting and controversial. Future systems might include the ability for a surgeon to program the surgery and merely supervise as the robot performs most of the tasks. The possibilities for improvement and advancement are only limited by imagination and cost.
DISADVANTAGES OF ROBOT-ASSISTED SURGERY
There are several disadvantages to these systems. First of all, robotic surgery is a new technology and its uses and efficacy have not yet been well established. To date, mostly studies of feasibility have been conducted, and almost no long-term follow up studies have been performed. Many procedures will also have to be redesigned to optimize the use of robotic arms and increase efficiency. However, time will most likely remedy these disadvantages.
Another disadvantage of these systems is their cost. With a price tag of a million dollars, their cost is nearly prohibitive. Whether the price of these systems will fall or rise is a matter of conjecture. Some believe that with improvements in technology and as more experience is gained with robotic systems, the price will fall.6 Others believe that improvements in technology, such as haptic, increased processor speeds, and more complex and capable software will increase the cost of these systems.9 Also at issue is the problem of upgrading systems; how much will hospitals and healthcare organizations have to spend on upgrades and how often? In any case, many believe that to justify the purchase of these systems they must gain widespread multidisciplinary use.9
Another disadvantage is the size of these systems. Both systems have relatively large footprints and relatively cumbersome robotic arms. This is an important disadvantage in today’s already crowded-operating rooms.9 It may be difficult for both the surgical team and the robot to fit into the operating room. Some suggest that miniaturizing the robotic arms and instruments will address the problems associated with their current size. Others believe that larger operating suites with multiple booms and wall mountings will be needed to accommodate the extra space requirements of robotic surgical systems. The cost of making room for these robots and the cost of the robots themselves make them an especially expensive technology.
One of the potential disadvantages identified is a lack of compatible instruments and equipment. Lack of certain instruments increases reliance on tableside assistants to perform part of the surgery.6 This, however, is a transient disadvantage because new technologies have and will develop to address these shortcomings.
Most of the disadvantages identified will be remedied with time and improvements in technology. Only time will tell if the use of these systems justifies their cost. If the cost of these systems remains high and they do not reduce the cost of routine procedures, it is unlikely that there will be a robot in every operating room and thus unlikely that they will be used for routine surgeries.
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