Medical Device & Diagnostic Industry
Magazine
MDDI Article Index
Originally Published January 2000
TECHNOLOGY 2000
Technology Forecast: New Prospects for Medical Devices in 2000
Medical devices in the next century will take advantage of stronger, lighter materials, nanoscale components, and faster processing capabilities.Gregg Nighswonger
Predictions of what medical care may be like in coming decades offer dramatic images of advanced healthcare. Among the visions of things to come are hospital ventilation systems capable of monitoring ambient air to identify the presence of visitors who may be capable of spreading infectious disease within the facility, implanted insulin reservoirs or active nanocapsules of pancreatic cells to treat diabetic patients, and implantable devices capable of restoring hearing or vision. Other systems would allow physicians miles removed from their patients to both monitor their condition and provide therapy. On a more fanciful note, Jurgen Bey, a member of the Dutch collective Droog Design, has suggested that, in the future, human bodies might be used as time capsules by taking advantage of prostheses and implants. Described in a recent New York Times Magazine article, Bey's concept entails engraving information that could conceivably prove valuable upon exhumation to future populations on implantable devices such as pace-makers, joints, and dental implants.
Although it may be questionable whether future generations will have much interest in details inscribed on implanted medical devices, the stories that encompass the passing of conventional medical devices into a new age of microelectronics, artificial intelligence, and advanced materials are worth exploring. There will undoubtedly be significant changes in most categories of medical devices. This article, however, will focus on five areas: orthopedics, gene therapy and tissue engineering, functional electrical stimulation, sensors, and endoscopy.
ORTHOPEDICS AND HUMAN PERFORMANCE ENGINEERING
Prosthetics and orthotics engineering has undergone tremendous technical growth in the last few decades. Significant advances in materials technology, microprocessors, and design systems are resulting in devices that are stronger, lighter, and function in a more natural manner.
Increasing use of computer-based design systems has had a profound influence on the work of prosthetists as well as orthotists—yielding a unique blend of traditional methods and advanced technology. Alan Turner-Smith, of the King's Healthcare Rehabilitation Centre (London) has been involved with the center's Telemate program—European-wide network that has been established to share multidisciplinary training and education in assistive technology. Asked to identify the areas where the most dramatic advances are being seen, he replies: "Service delivery is the area being advanced. That is, device fitting and efficiencies of not having to keep plaster casts, and being able to rectify existing designs easily."
He suggests that the current technologies are a blend of the traditional craft of the prosthetist and orthotist with the application of high-technology solutions. He predicts that "The balance of craft and technology will continue, but software improvements—speed, quality of rendition of 3-D objects, possibilities of virtual reality, and force feedback—will make the interface more intuitive for the prosthetist."
Turner-Smith also suggests that the greatest challenge to prosthetics development in the 21st century will be personalized design: "That is, use of composite materials and control systems to solve individual demands at the cost of mass-produced devices. Prosthetists will have to either get it right the first time or make the solution so cheap that the represcription is not costly."
Human performance engineering encompasses a broad range of biomedical engineering interests. Its focus is on enhancing the performance and safety of humans executing tasks. George V. Kondraske, director of the Human Performance Institute at the University of Texas (Arlington, TX) suggests that the instruments used to measure human structure and performance have been improving rapidly in recent years—equaling advances in base technologies such as sensors, signal conditioners, and microprocessors. He describes the 1990s as a decade of change in which off-the-shelf components began to replace fabricated devices and systems—a trend that is likely to spread.
Despite recent technological advances, however, some experts have noted that an imbalance exists with regard to the commercial availability of needed tools for the field. According to Kondraske, the situation will improve in the future but "commercial availability will still be 'behind.'" He explains that "The reasons are complex and, in my opinion, mostly related to lack of overall conceptual frameworks that are employed on a widespread basis. There is activity ... that I believe is drawing attention to such issues and moving things in the right direction. However, the majority of researchers are content to pursue avenues of research that ignore such
Kondraske further notes that the field is still relatively young in nature and is following a natural maturing process, but is "not at all yet mature." He explains: "One example is that nearly every field dealing with human performance has publications within it that deal with instrumented measurement of 'something' related to human performance. A number of these discussions are actually in textbooks and not merely in journal articles. A second example is that there appears to be an increasing awareness regarding the need to deal with issues such as standardization. If a field is not in a maturing process, such issues don't even get recognized. A third example is that some major organizations have embarked on projects related directly to human performance measurement. They seem to recognize that progress has occurred and it is time to 'take a new look.' For example, about two years ago, the Social Security Administration started a project of reengineering the disability determination process. Again, due to limited widespread dissemination and consideration of many of the conceptual issues, I don't see the outcome of any of the current efforts leading to any panacea. However, these are signs of the maturing process."
Kondraske views the greatest challenge to human performance engineering in the next century to be dealing "with the complexity of the human system and its performance in an organized, systematic way—and for a general consensus to be reached regarding what that way would be. In my opinion, this will require a sophisticated view of the human that is rather different than that which is traditionally put forth in the medical world. We will get something that we don't have now, such as the ability to quantitatively characterize performance of different subsystems in an efficient, viable way, and to use such characterization for a wide range of 'long dreamed of' predictive uses." These might include predicting driving ability, sports performance, and the ability of an impaired person to live independently, he adds.
He suggests that the field's greatest potential is "wherever there is a human and a task." He adds that "This is everywhere. Without specifying all the reasons why, I believe that the greatest short-term potential is in medically related applications, where measurements and special analysis software based on new concepts can be combined to achieve functionality beyond that of simple measurements—that is, the assessment of the measurements. A close second is the sports field where acceptance of new methods may be easier to achieve."
MAKING NANOSTRUCTURES THAT ASSEMBLE THEMSELVESAs tomorrow's medical devices and related components become smaller in size, greater emphasis will be placed on microengineering and microsystems technology. Current efforts in these fileds are focused in part on lithography techniques that can be applied to microfabrication challenges. A recent development by researchers at Princeton University (Princeton, NJ) involves a technique that provides the basis for self-assembly of polymer microstructures. Their success in creating ultrasmall plastic structures involves a novel technique that they believe will prove less expensive and more versatile than previous methods. The nanofabrication technique is expected to aid development of a new generation of miniature device applications, ranging from microprocessors to devices for sorting DNA molecules. Led by Stephen Chou, PhD, professor of electrical engineering at Princeton, the group found that, working with little specialized equipment, a flat sheet of plastic resin could be coaxed to assemble itself into a minute, perfectly ordered array of pillars that are approximately one-half micron in height and width. Chou believes that the technique can be refined to yield even smaller structures. The researchers accidentally discovered the technique while working on another nanofabrication process called imprinting, which was also invented by Chou. The researchers were pressing a mask into polymer when dust prevented the two pieces from coming together. When they later examined the polymer, it contained a pattern of pillars--even though the mask had never touched it. In addition to growing by themselves, the pillars had arranged themselves into a perfectly ordered array. "It was a very surprising discovery. No one had ever seen such a thing," says Chou. Chou dubbed the new approach LISA (lithographically induced self assembly). Although the initial research involved use of a polymethylmethacrylate, the LISA process is expected be applicable to other polymers and, perhaps, single-phase materials such as semiconductors, metals, and biological materials, says Chou. He suggests that, "with proper design, a single crystal lattice of a pillar array with predetermined diameter, period, location, and orientation could be achieved over an entire wafer."
Chou believes that the pillar pattern would be appropriate for a number of applications. One long-term application is in the design of ultrasmall circuits, according to the researchers. "Using the LISA process, you can fabricate your wires first, then it will assemble your devices between the wires on its own," says Chou. He also suggests that LISA could be much better suited to mass production than the most common nanofabrication technique, photolithography. So far, LISA cannot make features as small as those produced by photolithography, but that may change, Chou believes. One hope is to set up a repeating process where a relatively large mask makes many pillars, which would then be used as masks to make a new set of even smaller pillars. "In principle, you can get smaller and smaller and smaller things," he says. Currently, Chou is testing LISA with the same material used in Plexiglas, but he believes the technique will work with metals and other nonpolymer materials. |
GENE THERAPY AND TISSUE ENGINEERING
Much of the emphasis in current medical research is not on finding cures for disease, but on developing new methods for predicting and preventing disease. This is particularly true in the current efforts involving gene therapy. Programs such as the Human Genome Project have been focused, at least in part, on increasing understanding of our genomic structure so that disease processes can be more clearly understood and patients at risk for a given disease can be more easily identified.
In addition, tissue engineering is said to be among the most rapidly growing fields within biomedical engineering. It is expected to continue to play a significant role in cell and gene therapies over the next few years. Tissue engineering, in essence, involves the application of certain principles of biology and engineering to the development of substitutes capable of restoring, maintaining, or improving tissue function. There are two widely recognized categories of tissue engineering: in vitro construction of bioartificial tissues, and in vivo alteration of cell growth and function. Both these areas of interest are undergoing growth prompted by advances in various areas of technology, ranging from nanotechnology and computers to new materials.
According to François Berthiaume, PhD, of the Harvard Medical School and Shriners Burns Hospital (Boston), "The construction of tissues in vitro remains a daunting challenge because of the difficulty in overcoming transport limitations through tissue cell mass. There are a few cases where this is not a problem, such as in cultured skin, which is produced as thin layers of only a few cells. David T. Mooney, of the Massachusetts Institute of Technology (Cambridge, MA) adds, "A significant challenge in fabricating devices is either to develop processing techniques for natural biomaterials that allow reproducible fabrication on a large-scale basis, or to develop materials that combine the advantages of synthetic materials with the biologic activity of natural biomaterials." He further suggests that, in order to accomplish this goal, CAD/CAM techniques may be employed successfully in the future.
Berthiaume suggests that micropatterning may also prove to be a valuable method of improving tissue construction. "One of the most important recent advances in in vitro tissue construction is the development of techniques to micropattern cells. These techniques, adapted from those used in the semiconductor industry to generate computer chips, allow one to deposit cells on a surface at precise locations," says Berthiaume. "These methods are currently limited to two-dimensional surfaces, although there are efforts to develop such approaches in three dimensions."
He explains that micropatterning technologies offer the potential to improve tissue engineering in a number of ways. "First, by controlling the location of cells, it is possible to create microchannels reminiscent of capillaries in vivo, which could improve nutrient transport. Second, micropatterning can be used to maximize cell-cell interactions between two different cell types. For example, hepatocytes cultured on plastic exhibit much better function in the presence of a feeder layer of mesenchymal cells. Direct contact between the mesenchymal cells and hepatocytes is required for this effect to take place. Third, in applications where cell migration plays an important role, such as nerve regeneration, patterned surfaces may help direct or speed up the migration process."
Berthiaume also identifies the use of stem cells as an emerging area of tissue engineering. Derived from the bone marrow or certain embryonic progenitor cells, they have the ability to differentiate into several types of cells. Because of this, says Berthiaume, "they could be used to create more-complex tissues than what is possible with current approaches using one or two cell types. Such cells could be seeded into polymer matrices where they could be induced to grow and differentiate in vitro prior to implantation. Alternatively, the polymer implants could be designed to recruit stem cells in vivo by releasing factors that specifically attract these stem cells. Ultimately, the new tissue will be made up of cells derived from the host, which avoids problems related to immune rejection. Further studies to elucidate the nature of these factors will be necessary to make such approaches possible."
Mooney suggests that tissue engineering could one day offer alternatives to whole-organ or tissue transplantation. Research in the area has been motivated to a great extent by the ongoing shortage of tissues available for transplantation, which has resulted in patient deaths from the lack of available tissue or use of suboptimal therapies because of the shortages.
Some research efforts have been focused on investigation of selective cell transplantation as an alternative to whole organ transplantation. There are a number of advantages to this approach. Using cell transplantation to reconstruct functional tissue in vitro would alleviate problems associated with donor organ shortages because the procedure would require only a small number of cells from the donor. In vitro expansion of the small amount of harvested cells would create potentially unlimited supplies of tissue. In addition, the risks typically associated with surgical procedures could also be decreased. The need for immunosuppression during transplantation of autologous cell transplants could also be reduced, according to most experts. Some suggest that, eventually, it will be possible for cells that have been harvested from a patient to be modified in order to replace defective genes prior to reimplantation.
Some investigators have focused research efforts on development of specialized vehicles for delivery of engineered tissue for cell transplantation. Researchers at Massachusetts General Hospital (Boston), for example, have used synthetic biodegradable polymer scaffolds as delivery vehicles for cell tissue. The technique allows cells to be delivered and immobilized at a specific site, and to act in the manner of a template for tissue development. The scaffold also provides a space in which the transplanted cells can reorganize into higher structures. The technique avoids long-term foreign body response by the patient's system because the scaffold eventually resorbs. The researchers have formulated a number of clinical applications that are undergoing investigation as a means of achieving permanent replacement of lost organ function.
CREATING NEW THIN-FILM MATERIALSThe development of a number of medical devices has been made possible in part by the application of advanced polymer thin-film materials. Efforts to create new polymer thin-films by using blends of polymers, however, have been hampered by the challenge of blending certain polymers that simply do not mix. Physicists at North Carolina State University (NC State; Raleigh, NC) are collaborating with materials scientists at the State University of New York (SUNY; Stony Brook, NY) to address the problem. The team is focusing on the specific processes that are involved as the dimensions of polymer blends shrink. They are also exploring how enhanced thin-film materials can be generated by exploiting these processes. Says Harold Ade, MD, associate professor of physics at NC State, "We know that, as a material shrinks, its large-chain molecules—its polymers—no longer have room to 'stretch out' as they ordinarily would. This affects their spatial relationship to other polymers and, in some cases, the 'mixability' of the polymers themselves." Ade explains that the challenge to the researchers is to learn how to understand and control these effects and use them advantageously. The goal is to promote a consistent mixture of polymers throughout a thin-film blend without limiting the types of polymers used. The group is attempting to exploit the process of reduction in entropy, described as a measure of the number of possible molecular arrangements in a material. They indicate that this process occurs as a result of miniaturization. The researchers recently reported that, for the first time, highly dissimilar polymers can be completely blended into a thin film through the application of entropy-reduction principles. Ade explains that "It's sort of like getting water and oil to mix. The beauty of nature is that, if a polymer blend is shrunk small enough, the emulsifier utilized is essentially prevented from associating with other emulsifier molecules. There's no room for the emulsifier to arrange itself in such a way due to the confined space." When emulsifiers are used to mediate polymer blending and stabilize mixtures, the emulsifier molecules can associate with other emulsifiers. When this occurs, they lose much of their stabilizing ability and the polymers can separate. The result is most often unacceptably large modulations on the surface of the material and inconsistent internal structure. Flaws of this type usually render a material useless for most applications that require a perfectly flat surface and where tight structural tolerances must be satisfied.
Describing the method of polymer blending, Ade says "The thin-film polymer blend we created was made from very dissimilar polymers but had a perfectly flat surface and a completely mixed, uniform structure when reduced to nanoscale. This is the first time we've seen that in highly immiscible systems." The scientists speculate that the technique should be applicable to most technological processes that rely on ultrathin polymer coatings. |
NEW TREATMENT OPTIONS IN CARDIOLOGY
Innovations in imaging techniques, minimally invasive surgery, and other areas of disease diagnosis and treatment are all shaping the future of cardiology. Among the most dramatic areas of current research, however, is the use of stents to open blood vessels and arteries that have been closed by a buildup of plaque or to strengthen tissue threatened by the presence of an aneurysm.
Medtronic Inc. (Minneapolis) recently received marketing clearance for its AneuRx stent graft system used to treat abdominal aortic aneurysms (AAAs), a bulge in the wall of an artery. Medtronic describes the technology as "the first new treatment option for AAA in 40 years." The formation of AAAs is generally associated with cellular changes caused by arteriosclerosis, which damages and weakens the artery wall. Timely diagnosis and treatment of the aneurysm are critical to preventing rupture of the aorta, which most often results in the patient's death.
Medtronic's AneuRx system uses self-expanding diamond-shaped rings to create a "friction fit".
The company indicates that results from a prospective, nonrandomized, multicenter trial in the United States demonstrated the AneuRx stent graft to be as effective as conventional treatment of AAA. The firm claims use of the stent has the potential to cut major complications associated with cardiac surgery by half. Results of the study, which involved 482 patients, also suggest that the technique improved patient quality of life by reducing hospital stays from 9.3 days to 3.4 days and reducing the time to ambulation from 3.6 days to 1.4 days.
Says Christopher Zarins, MD, chief of vascular surgery at Stanford University School of Medicine (Palo Alto, CA) and clinical investigator in the study, "Endovascular repair of AAA is truly a breakthrough in that it offers significant potential benefits to patients. In addition to being as effective as open surgery, patients who received the AneuRx device also had fewer serious complications, spent less time in the hospital and ICU, and experienced faster recoveries."
Conventional treatment of aneurysms has entailed open surgical repair, with an average hospital stay of 7 to 12 days and a recuperative period that can last as long as six months. The procedure itself involves making a large abdominal incision and clamping the aorta above and below the aneurysm. Opening the aorta, a surgical graft is sewn in at the diseased site and the aorta is closed.
During the AneuRx procedure, an incision is made in each groin area. A delivery catheter is used to deliver the stent graft into the femoral artery and guide it through the aorta to the location of the aneurysm. The stent graft is placed within the aneurysm where it expands to fit within the diameter of the aorta. The result is a new path for blood flow and a significant reduction in the pressure on the aneurysm. The catheter is withdrawn after placement of the stent graft.
The AneuRx endovascular stent-graft system consists of catheter-mounted grafts that form new passageways to carry blood to the legs past potentially lethal aneurysms.
The AneuRx system uses self-expanding, diamond-shaped, nickel titanium stent rings to create a "friction fit" to anchor itself to the vessel wall without the need to puncture the vessel with hooks or barbs. Physicians can use extender cuffs to modify the length or diameter of the implanted graft as a means to address implant challenges and changes in aneurysm size and shape. The stent graft exterior is designed to prevent kinks or twisting, and device migration over time, which can require surgical repair.
FUNCTIONAL ELECTRICAL STIMULATION
Electrical stimulation has been found to be an effective means for restoring muscular function. Implantable functional electrical stimulation (FES) systems have been developed to restore and maintain control of bowel and bladder activity, lung function, and limb movement. All such systems operate by applying an electrical current to nerves through the use of implanted electrodes. Increased understanding of precisely how the human nervous system functions, coupled with technological improvements is providing the foundation for notable improvements in years to come.
Functional electrical stimulation (FES) technology has been successfully used in treating a number of medical conditions. FES has been a critical part of orthotic and prosthetic devices that can be used to restore ambulation and grasping functions to patients with spinal cord injuries. In addition, FES technology has been proven effective in treating epilepsy and tremors associated with Parkinson's disease. Other applications include control of incontinence and deep brain stimulation to relieve rigidity.
Looking to the future of FES applications, P. Hunter Peckham, director of the Cleveland FES Center, has suggested that advances in implantable stimulation methods are expected to occur in two areas: the integration of control and stimulation functions within implantable systems, and the potential applications of microinjectable neurostimulators.
A number of systems are currently in development in which external neuromuscular stimulators are capable of communicating with and controlling implanted sensors. A configuration of this sort would allow the stimulation device to both power the sensor and telemeter the data generated by the sensor to the controller located outside of the body. The controller would then be able to process the data and transmit appropriate functional commands back to the stimulation component. Such a device is under development at Case Western Reserve University (Cleveland) for more-advanced neuromuscular applications. The command data could be derived from various physiologic sources, including joint position or feedback control loops, according to Peckham.
Research at several centers is focusing on development of microinjectable neurostimulators--small capsules capable of being inserted through a tiny injector directly into muscle tissue for nerve activation. Numerous such devices could be placed in particular muscles and controlled via a single external coil that surrounds the implantation site.
BIOCHIPS BATTLE TUBERCULOSIS EPIDEMICA new biochip technology developed by Russian and American scientists could offer some hope of stemming the global resurgence of tuberculosis. Developed by the U.S. Department of Energy's Argonne National Laboratory and the Russian Academy of Sciences' W.A. Englehardt Institute of Molecular Biology (Moscow), the technology is expected to help combat the new variety of drug-resistant strains of the disease. The World Health Organization indicates that tuberculosis kills more youth and adults than any other infectious disease, including AIDS and malaria combined. The greatest challenge of the current tuberculosis epidemic is that several different bacterial strains can cause the disease, and each is resistant to different drugs. Identifying the strain that is affecting a given patient and determining the optimal antibiotic for combating that strain is the critical element in controlling the disease. Argonne intends to use the biochip technology in research to distinguish between different tuberculosis strains. Initially, the tests will be performed on segments of genetic material removed from tuberculosis bacteria. Human trials are not expected to begin until the method has been proven successful. The biochips are designed to perform a multitude of biochemical reactions simultaneously, and have been found to perform satisfactorily in laboratory tests. "But this will be their first test in the realm of real-world medical diagnostics," says Harvey Drucker, Argonne associate director. Because it takes weeks or months to identify specific tuberculosis strains, patients are often prescribed several antibiotics simultaneously. Says Drucker, "If our biochip can do the job, physicians can prescribe the most effective treatment without delay." The biochip is a glass slide containing up to 10,000 gel pads, each of which functions like a miniature test tube. A short strand of DNA is attached to each gel pad. By fixing only one strand to each gel pad, the chip takes advantage of the natural tendency of each DNA base to pair with its complementary base. To begin the test, a sample of unknown single strands of tuberculosis DNA is applied to the chip and allowed to naturally pair up in the gels with single strands of tuberculosis DNA with identified drug resistance. A direct match will identify drug-resistant tuberculosis strains. By changing the DNA samples in the gels, scientists can also use this technique to diagnose an unlimited range of other diseases. One of the most significant advantages of Argonne's biochips over conventional biochips is that they can be cleaned and reused up to 50 times. In addition, the gel's larger size allows them to hold up to 1000 times the material, making them more sensitive than any other biochip. "With the advanced biochip technology, we'd be able to get all the information we need in a couple of hours, without any false positives," Drucker explains. "The fact that it has been shown to work, and that the test wasn't difficult to perform, shows us that this has a lot of potential." |
PIVOTAL ROLES OF SENSORS
Sensors have been identified by some researchers as a technology that is capable of transforming healthcare. Conventional laboratory testing is expected to be replaced eventually by sensors worn by patients or implanted within them. Hospital beds might be equipped with sensors that will initiate ventilation during surgical procedures or start the flow of IV fluids during the recovery period. Japanese researchers are even focusing efforts on development of a toilet seat with built-in sensors capable of weighing a patient who sits on the device, then testing the bacteria and sugar levels in the urine and transmitting the data directly to the patient's physician.
Sensor technology will be a critical component of advanced monitoring systems. Combined with artificial neural networks, they form the basis for developing "smart" devices capable of providing functional support to clinicians in hospitals and in home healthcare environments . Intuitive systems that will complement staff in surgical suites, ICUs, and patient rooms will be built using sensors that offer small size, and increased stability, reliability, and accuracy.
The technology used to produce sensors of various types is also expected to undergo radical changes in coming years. For example, YSI Inc. (Yellow Springs, OH) is collaborating with the Naval Research Laboratory (NRL; Washington, DC) to assess the technical feasibility and market potential for NRL's Matrix Assisted Pulsed Laser Evaporation (MAPLE) technology in developing microbiosensors. The microsensors would be used in a wide range of biosensor applications, including medical. YSI is evaluating MAPLE technology for its ability to pattern a variety of organic films at the microscale level without loss of functionality. Use of the technology to create microbiosensors is part of a larger development effort in microfluidic technology. Working with NRL and its advanced laser processing techniques, YSI has been able to dramatically accelerate its development and use of the microfluidic analyzer and to expand its capabilities in the area of biosensor and microfluidic analyzer manufacturing.
Clearly, the Internet is beginning to have a recognizable influence on healthcare delivery. Among the potential uses of the Internet is remote monitoring of patients and telemedicine. A number of recent reports in the popular press have focused on use of systems such as the Health Buddy manufactured by Health Hero Network (Mountain View, CA). According to the company, the pagerlike device could be used in conjunction with smart systems to measure a patient's blood pressure, glucose levels, temperature, and other parameters. Readings would be collected for access via the Internet by the patient's physician. In years to come, such systems are expected to increase patient access to medical care while containing related costs.
ROBOTICS TECHNOLOGY ENHANCES ENDOSCOPY
Endoscopy has become a widely accepted form of intervention for applications ranging from gynecology and abdominal surgery to orthopedic procedures and thoracic surgery. Endoscopic technology is also providing the basis for robot-assisted surgery, which is expected to have a dramatic impact on surgical techniques in the future. According to estimates by Ethicon Endo Surgery Inc. (Cincinnati), endoscopic surgery is used on the majority of patients undergoing cholecystectomy, appendectomy, hernia repair, certain bowel procedures, and gastroesophageal reflux disease (GERD) treatment.
A system that has received significant attention in orthopedic surgery is the ROBODOC surgical assistant system, developed by Integrated Surgical Systems Inc. (Davis, CA). The systems is used to precisely ream the femoral canal in preparation for hip implant placement. The system is proving successful in decreasing the incidence of fractures that can occur as part of the reaming and implantation procedures of total hip replacement.
Robotic tools, such as the da Vinci surgical system from Intuitive Surgical Inc. (Mountain View, CA), are designed to improve the accuracy of endoscopic procedures.
Minimally invasive surgery that has proven effective for complex cardiac procedures is also benefiting from the development of robotic systems to enhance endoscopy. Another aspect of research to improve the application of endoscopic surgery has been to improve the manner in which surgeons work with endoscopic instruments. At least one new system has evolved from attempts to integrate technology based on that developed originally for battlefield use. Intuitive Surgical Inc. (Mountain View, CA) has developed the da Vinci surgical system to improve the accuracy of endoscopic cardiac surgery. The system has been designed to immerse the surgeon within a 3-D environment while performing minimally invasive procedures. In addition to cardiac applications, the company has installed systems and completed more than 400 cases in Europe, including vascular, urological, gynecologic, and general-surgery procedures. Ohio State University Medical Center (Columbus, OH) began a clinical trial in August 1999, and East Carolina University (Greenville, NC) is also set to begin a clinical trial. The Ohio State trial will focus on performing internal mammary artery procedures and will then move into cardiac and intracardiac procedures.
Although introduction of the technology is expected to be several years away, Ralph J. Damiano, MD, chief of cardiothoracic surgery at the Pennsylvania State University Hershey Medical Center, was recently part of an international team that performed the first voice-controlled, robotically assisted heart- bypass surgery on a human. The bypass graft procedure was performed through three small ports while the surgeon was assisted by the Zeus Robotic Microsurgical System designed by Computer Motion Inc. (Santa Barbara, CA). The system consisted of a voice-activated robotic arm that was used to control the endoscope, and two robotic arms that manipulated surgical instruments. According to Damiano, "This type of surgery will have a revolutionary impact, not only on heart surgery, but on many types of procedures. Once the robotic system becomes cost-effective, there is little reason why you would not want to use it wherever possible. It enhances a physician's dexterity."
FROM TELEMEDICINE TO E-HEALTHThe convergence of information technology and telecommunications, including Internet technologies, is emerging as a key tool to drive increased efficiency and effectiveness in health systems worldwide. With part of its roots in medical research for military and space applications, telemedicine is expected to make it possible to link medical expertise with patients in the most distant locations--providing clinicians with valuable new tools for remote monitoring, diagnosis, and intervention. Among the technologies that will play critical roles in telemedicine development are wireless communications, virtual reality, photonics (with ample capacity to support a wide range of high-bandwidth multimedia applications), and advanced networking. Australian researchers have been particularly active in developing both the technology and infrastructure for practical applications of telemedicine. A recent report commissioned by Australia's National Office for the Information Economy Health identifies the emergence of a relatively new concept called e-health, which is described as an umbrella field that encompasses telemedicine. Several factors are identified as driving e-health, including increased efficiencies from improvements in business and clinical practices and processes, and demand from consumers for improved access to quality healthcare information and services. The report states that healthcare lends itself to the "strategic application of online technologies because of its size, the current inefficiencies of paper-based records, the intense need for up-to-date information to provide quality healthcare, and because interest is growing among consumers in Australia and overseas in using the Internet to access a range of information and services." A full range of e-health activities is described in the report, including trained "nurses making house calls in rural areas equipped with hand-held computers connected via a mobile phone to databases at headquarters; highly qualified cardiology nursing staff answering telephone calls in the call center of the National Heart Foundation; radiologists using a combination of teleradiology and live videoconferencing to link from Adelaide to Alice Springs; and general practitioners accessing powerful new pharmacy databases and producing electronic scripts."
The convergence of telemedicine and healthcare services is expected to continue, keeping pace with the development of the Internet and other electronic resources. With continued progress in developing new technologies and the expected increase in e-health applications, expectations appear high for significant improvements in healthcare delivery for providers, consumers, and funding agencies alike. |
CONCLUSION
A number of factors appear to be driving the rapid development of new medical device technologies. In addition to the availability of increased computing power, stronger yet lighter materials, and increased understanding of the functioning of the human body, certain social factors are exerting their own influence. The end of the cold war and diversion of funds and resources from defense efforts have opened the doors of our national laboratories and research centers to developers—increasing the impact of technology-transfer programs on device innovation.
The focus of current medical device design is gradually shifting to new areas. Ergonomics, for example, is rapidly becoming a far more important design consideration than in the past, as is modularity. Incorporation of networks and devices that make use of Internet capabilities will add yet another dimension to medical device function. The result may well be remarkably paradoxical in nature: New device design considerations will yield products that are more complex in nature, yet simpler for clinicians to operate. They will no doubt be more expensive, yet may prove more cost-effective in use than their current counterparts.
Gregg Nighswonger is executive editor for MD&DI.
Return to the MDDI January table of contents | Return to the MDDI home page
