Medical Device & Diagnostic Industry Magazine
MDDI Article Index

Originally Published MDDI July 2005

Cover Story

MD&DI’s Top Ten technologies

MD&DI identifies and explores the Top 10 medical device technologies that drive industry today—and the applications that use them.

In an industry with so many innovations leading to so many radical improvements in patient care, it is no easy task to determine 10 top application areas and technologies. But we at MD&DI decided to give it a try anyway, to showcase the sectors with the most important developments affecting patient care, clinical practice, product creation, and the device industry as a whole. Of course, this list does not mean that other areas are less important, but we feel these 10—although in no particular order—are having a bigger effect at this time.

What constitutes a top 10 technology area? There is no set definition. Rather, we set out to find sectors with new products making significant contributions to healthcare. We looked for transformative innovation that was affecting the industry right now. Hence, futuristic areas like nanotechnology aren’t on this list—but don’t be surprised if they make the cut a few years from now.

You may not necessarily agree that these are the top 10 medical technologies. But we hope you’ll agree that they are important and worthy of recognition.

Implantable Elution Devices: Reshaping the Industry
Carotid Artery Stents: A Step Toward Preventing Strokes
Heart Assist Devices: Keeping Patients’ Interest at Heart
Artificial Bone and Skin Grafts: New Materials Provide Better Scaffolding
Artificial Orthopedic Disks: Flexible Disks Imitate Vertebrae
Nucleic Acid–Based IVDs: Diagnoses in a Day, Not Weeks
Medical Lasers: The Wavelength of the Future
Medical Imaging Technology: The Value Beneath the Surface
Wireless Technology: Hospitals and Homes Go Unplugged
Computer-Assisted Surgery: The Digital OR

Implantable Elution Devices: Reshaping the Industry

Erik Swain

Boston Scientific leveraged outside suppliers and vendors to ensure the Taxus eluted accurately and effectively.

Since 2003, it’s been impossible to discuss the state of the medical device industry without delving into drug-eluting stents. For patients, clinicians, companies, and investors, these stents have brought benefits of a magnitude rarely seen in the device sector. As new generations are developed, and elution principles are applied to other technologies, their tremendous effect should continue for the foreseeable future. Some consider the two FDA-approved drug-eluting stents—Cypher from Johnson & Johnson’s Cordis Corp. (Miami) and Taxus from Boston Scientific Corp. (Natick, MA)—to be the first blockbuster devices.

“This is part of a progression of technologies dealing with coronary artery disease,” says Michael Drues, PhD, president of Vascular Sciences (North Grafton, MA). “First there was bypass surgery, then angioplasty, then stents, and now there are drug-eluting stents. In general, each one has given better clinical outcomes than its predecessor.”

The clinical benefit has come in the reduction of restenosis rates. As many as one-third of patients receiving bare-metal stents suffer from reblockage of the artery. Drug-eluting stents reduce the inflammation caused by the stent pressing against the artery, dropping restenosis rates into single digits.

This benefit caused “a massive shift in the market in a very short period of time,” says Thomas Gunderson, managing director and senior research analyst for Piper Jaffray (Minneapolis). “It went from four or five companies selling bare-metal stents to two selling drug-coated stents, which soon accounted for more than 80% of the market. It was quickly adopted by clinicians because it was a way to do the same procedure while reducing complications.”

The development of drug-eluting stents also significantly affected industry. For one, it signaled the emerging importance of combination products. Henceforth, device companies need to consider whether a device combined with a drug or biologic will provide a better clinical outcome. If so, that means they need to figure out how to work with other branches of FDA aside from CDRH.

Drug-eluting stents have also changed the way device companies work with the Centers for Medicare and Medicaid Services (CMS; Baltimore). Traditionally, device companies hadn’t begun the CMS coverage process until after FDA approval. But J&J worked with CMS to secure coverage, coding, and payment for Cypher before obtaining FDA approval, allowing for reimbursement as soon as the product hit the market. This opened a new level of communication between CMS and industry. Of course, it helped that J&J and Boston Scientific were willing to do outcomes research up front. Whether other firms will be expected to do the same, and whether they can afford it, remain to be seen.

Although the technological challenges were tremendous, J&J and Boston Scientific found partners in other disciplines who could help overcome those challenges. For example, after J&J came up with the idea for a drug-eluting stent, it went to SurModics Inc. (Eden Prairie, MN), for help with developing a coating. “We said we thought we had a technology that could be useful, and that began a process of years of testing,” says David Wood, general manager of SurModics’ drug-delivery business. Both J&J and Boston Scientific were able to leverage these kinds of outside resources to develop coatings that would stay on the stent, properly contain the drug, be compatible with the human body, and elute the drug at the correct rate over the correct period of time. The difficulty of this task is evidenced by what’s happened to their competitors: some have failed, and others lag behind because they’ve not been able to get the coating right.

J&J worked with CMS to secure reimbursement for its Cypher stent before obtaining FDA approval.

Carotid Artery Stents: A Step Toward Preventing Strokes

The Acculink uses a rapid exchange platform that offers device control, faster exchanges, and ease of use.

Erik Swain

As cardiovascular stents revolutionized treatment of coronary artery disease, so could carotid artery stents transform stroke prevention. In theory, carotid stenting and distal protection could supplant carotid endarectomy for some patients at risk of stroke. After all, coronary stenting supplanted bypass surgery for certain patients at risk of heart attack. In practice, it remains to be seen whether it will play out that way. But the 2004 FDA approval of Guidant Corp.’s Acculink carotid stenting system and Accunet embolic protection system gives U.S. clinicians a chance to find out.

Carotid endarectomy is a highly invasive procedure in which plaque is removed from a patient’s carotid arteries after an incision through the neck. By contrast, in the stenting procedure, the stent is inserted into a small puncture in the groin and then moved into position. It has emerged as a much-needed alternative for patients considered too great a risk for surgery.

But is the minimally invasive procedure going to be the preferred option?

“You have an extremely successful open surgery, and now the supposed solution is to do it intravenously with a different doctor, so that could lead to turf wars,” says Thomas Gunderson, managing director and senior research analyst for Piper Jaffray (Minneapolis). “It will be difficult, in my opinion, to prove that [carotid artery stenting is] better than a procedure that claims 95% success. The challenge will be training interventionalists to get up in the neck and brain to clean the carotids out without debris going northward.”

Michael Drues, PhD, agrees. Drues is president of Vascular Sciences (North Grafton, MA). He says that carotid stenting is a much more difficult procedure than coronary artery stenting. If plaque is dislodged into the brain, it could cause permanent brain damage, whereas if plaque is dislodged into the heart, permanent damage is less likely. Studies have shown that quality of life may not be lost when part of the heart can no longer function, but it may be lost to a great degree when part of the brain can no longer function, he says.

“The biggest competitor may be the status quo,” Drues says. Carotid endarectomy “is a good procedure for safety and effectiveness. Can it be made better in a less-invasive fashion?”

The key is distal protection, which helps prevent the plaque from traveling to the brain during the procedure. For Guidant, that means the performance of the Accunet may make or break the entire concept.

The design and manufacturing of carotid stents presents different challenges from coronary stents. The carotid arteries are much smaller, and it’s much more difficult to maneuver a device into them. “Ease of implantation and deliverability are major challenges,” says David Wood, general manager of the drug-delivery business for SurModics Inc. (Eden Prairie, MN). “You need to attach molecules to the surface of the catheter to make it slippery enough to maneuver in there. The catheter is made of a plastic that has quite a bit of friction—that’s where hydrophilic coatings come in.”

Clinical trials showed the Guidant system cut the likelihood of stroke in the blockage area compared with the conventional surgery. If those results are borne out in the real world, it could reshape stroke prevention.

Heart Assist Devices: Keeping Patients’ Interest at Heart

Maria Fontanazza

Top: The St. Jude Epic ICD allows for heart rate changes resulting from activity. Bottom: The left-VAD from Thoratec Inc. (Pleasanton, CA) is the only VAD approved by FDA for permanent implantation.

Devices that help the heart to function are one of the most fruitful areas for patients, caregivers, and companies. Whether implantable or external, electronic or mechanical, heart devices are becoming smaller and easier to implant. They are restoring quality of life to patients who would have had little hope a few years ago.

Pacemakers have developed significantly since their beginnings more than 40 years ago. Changes made to the leads have enabled implantation without opening the chest cavity. Lithium iodine batteries have extended pacemaker life from one year to up to more than 10 years, and new titanium casings have decreased electromagnetic interference.

The device’s ability to modify the heart rhythm with a person’s activity level has made it even easier to maintain a normal lifestyle. St. Jude Medical (St. Paul, MN) developed an algorithm for suppressing atrial fibrillation, which the company has incorporated into some of its pacemakers and implantable cardioverter defibrillators (ICDs). The technology’s pacing allows for heart rate changes resulting from everyday activities and sleep cycles.

For people who experience abnormally fast and erratic heartbeats, ICDs can offer relief. About the size of a pager, ICDs contain leads that are channeled to a pulse generator, which is implanted beneath the skin with a battery. When an ICD detects irregular rhythms, it shocks the heart back to a normal beat. Like pacemakers, some also record heart patterns that a doctor can review later.

In 2001, a fairly new system that incorporates either a defibrillator or pacemaker surfaced in the United States. Cardiac resynchronization therapy (CRT) devices restore the heart’s two ventricles to a simultaneous beat. While a pacemaker has only two leads for the right atrium and right ventricle, CRTs have a third lead in a vein on the left ventricle.

“Relative to just a basic defibrillator or pacemaker, the CRT is targeted for congestive heart failure patients who have a very poor ejection fraction, or amount of blood volume that gets out of the heart,” says Greg Aurand, senior medical devices analyst at Zacks Investment Research Inc. (Chicago). Poor synchronization enlarges the heart. CRTs can help shrink the organ down to a more-normal size.

Other devices that reduce heart muscle strain are ventricular assist devices (VADs), which vary in design. VADs include an energy supply, a control system, and a pump. For the energy-supply component, some use a battery and some use air. The control system and energy supply are external, and the pump can be either internal or external.

“They’re almost fully implantable now,” says Aurand. “They used to be partially implantable. The pump was outside the body and plugged into a wall, because the patients had no other way of power-sourcing the implant.” Modifications are currently being made to minimize the size of the devices and improve the battery for full implantation in the body.

“VADs have only been approved for a few years. From the patient and FDA perspective, it’s still a relatively new technology,” says Aurand. Initially a temporary fix until a donor was available, the devices are now also available to patients who have severe heart failure but don’t need a transplant.

External defibrillators are tools that can be found in airports, hospitals, and schools. Last year, FDA approved the first automated external defibrillator for over-the-counter sale. The biggest battle this technology will face is whether communities and businesses see an advantage despite the comparatively high cost.

Artificial Bone and Skin Grafts: New Materials Provide Better Scaffolding

Erik Swain

The Vitoss bone fillers, made by Orthovita Inc., mimic the chemical structure and composition of human bones, enabling ingrowth of the host bone.

Over the past several years, bone and skin grafts have come a long way. In many cases, they are using natural substances to be more compatible with the body. A number of applications have resulted from advances in surface technologies. For example, coatings that attract proteins can help the body accept the new graft. They may also contain calcium and other substances to foster regrowth. The end result is that grafts look better, feel better, and react to the body better than was even conceived of only a few years ago.

Some surgeons prefer to use the patient’s own bone or skin in procedures. However, for some reconstructive cases involving serious trauma, that proves impossible. And to reduce pain and complications, some clinicians would rather not harvest a patient’s bone or skin.

In come cases, advancement has come through tissue engineering. One example is the work of Orthovita Inc. (Malvern, PA), which has developed several synthetic biologically active bone fillers. Being biologically active is key: it can allow for stimulation of bone growth or fusion. One product, Vitoss, uses calcium phosphate to allow resorption, cell seeding, and ingrowth of host bone. It can do this because it mimics the chemical structure and composition of human cancellous bone.

Another company, Osteotech Inc. (Eatontown, NJ), specializes in regrowth of human bone and tissue, often for transplantation procedures. Among its advances is a demineralized bone matrix that is made from bone fibers and combined with surface modification techniques to maximize acceptance by the body. Regeneration comes from partnering biologically active tissue forms with nonbiologically active technologies.

On the skin graft side, Integra Lifesciences Corp. (Plainsboro, NJ) makes a dermal regeneration template that entices skin cells to regenerate for burn and reconstructive-surgery patients. It contains a replacement layer made from collagen and glycosaminoglycan and a temporary epidermal substitute made from silicone to control moisture loss.

These and other efforts are blurring the boundaries between the natural and the synthetic.

Artificial Orthopedic Disks: Flexible Disks Imitate Vertebrae

Maria Fontanazza

Top: DePuy’s Charité artificial disk is used in patients who suffer degenerative disk disease. Bottom: The Charité disk in the spine.

Innovative design combined with breakthrough clinical benefits means artificial spinal disks are a transformational technology. Although the devices have existed for about 20 years, their entry last year into the U.S. market offers more back-pain sufferers an alternative to spinal fusion surgery.

“The artificial disk has the potential to actually change the world of the spine, much like the world of the knee and hip has been changed by implants developed over many decades,” says Greg Aurand, senior medical devices analyst at Zacks Investment Research Inc. (Chicago).

The orthopedic devices will affect both the patient population and the spinal market. Global revenues for spine arthroplasty were $75 million last year, according to Anthony Viscogliosi, principal at Viscogliosi Bros. LLC (New York City). He predicts that by 2010, the market for nonfusion spine technology will reach more than $10 billion, the largest component of which will be disk replacement.

This segment has excited the industry’s major players in orthopedics, so much so that it has generated more than $1 billion in acquisitions. That, among other things, has spurred business creation: Viscogliosi Bros. counts about 130 start-ups in the spine field, almost all in the nonfusion arena. At least 30 companies are attempting to develop disk technologies.

So far, DePuy Spine Inc.’s (Raynham, MA) Charité is the only FDA-approved artificial disk. It is used in patients who suffer from degenerative disk disease at the lowest segments of the lumbar spine and who have not been helped by at least six months of nonsurgical treatment.

The high-density plastic sliding core, made of medical-grade plastic, is placed between and supported by two metallic endplates. These endplates are made of medical-grade cobalt-chromium alloy and have small teeth that fasten to the adjacent vertebrae. The flexibility of the disk imitates the spine’s natural movement to reduce further weakening of nearby spinal levels.

Implantable disks pose a threat to spinal fusion, a procedure that can limit mobility and increase pain over time. Spinal surgeons’ adoption of the disks remains to be seen, however.

“The artificial disks, at least the Charité in particular, go through the front of the body,” says Aurand. “Like many minimally invasive surgical procedures, it requires special training and use of new techniques and tools to get it up to speed.”

But if artificial disks catch on, they could significantly affect a spine surgeon’s business. “If one spine surgeon is not educated and trained on this technology, another one down the street will be,” says Viscogliosi. “Patients will go to the surgeon who can provide a solution for their pain.”

What lies ahead? Perhaps complete implantation, says Viscogliosi. “It will usher in a new wave of thinking to preserve motion in the spine, setting the stage for rapid growth in other areas of spinal nonfusion,” he says. These areas include disk nucleus replacement for low back pain and nonfusion surgical solutions for back pathologies, like adolescent scoliosis.

Cervical disks are also currently being developed and tested for use in the upper portion of the back. If investigational trials are successful, they could be available in a few years, says Aurand.

Nucleic Acid–Based IVDs: Diagnoses in a Day, Not Weeks

Brendan Gill

The Rapid Capture System from Digene (Gaithersburg, MD) can process 352 patient specimens in 61¼2 hours.

The potential of nucleic acid–based IVDs (NA IVDs) has captured the imagination of the public and industry alike. The technology’s allure—to help doctors diagnose or prescribe medicine or treatment based on a patient’s DNA—is the stuff of sci-fi movies. Although truly personalized medicine may be off in the distance, NA IVDs are significantly changing the world of diagnostics today.

The technology’s applications are in the hundreds, but infectious-disease control has benefited especially from NA IVDs. Products like the Procleix WNV Assay from Gen-Probe Inc. (San Diego) have improved blood screening for the West Nile virus. The assays, made available two years ago, are used to screen more than 80% of the U.S. blood supply.

“NA IVDs are far more sensitive and, in many cases, faster, than older diagnostic technologies,” says Dan Kolk, associate director of development at Gen-Probe. “This leads to detection earlier in the disease cycle. Most NA IVD tests can be performed in less than a day, whereas older tests took days, and, in some cases, weeks.”

NA IVDs are also improving sexually transmitted disease testing. Approximately 4 million cases of gonorrhea and chlamydia occur in the United States each year. NA IVDs are helping health professionals obtain faster, more-accurate diagnoses with better techniques. The test’s sensitivity and specificity have been improved through the development of target- and signal-amplification methods. Also, tests based on enzymatic target amplification have enlarged target molecules to be large enough for detection with reporter systems.

Pharmacogenomic products have also reduced the trial-and-error risk of drug prescriptions. Products such as Herceptin, from Genentech Inc. (San Francisco), are effective only if breast cancer cells have extra copies of the Her-2/neu protein. Better-targeted drugs have cut down on adverse reactions, which contribute to millions of hospitalizations a year.

NA IVDs will continue to improve on the strides made so far. Truly personalized medicine is still in the future, but NA IVDs will give a clearer picture of what that future looks like.

Medical Lasers: The Wavelength of the Future

Maria Fontanazza

IntraLase Corp. uses a computer-guided laser to reduce the risk of cornea cutting.

As the possibilities for laser technology continue to grow, it’s not unrealistic to say that someday lasers will be used in nearly every surgical procedure.

“For applications in laser surgery, we’re only scratching the surface,” says Elizabeth Tanzi, codirector of laser surgery at the Washington Institute of Dermatologic Laser Surgery (Washington, DC). “Laser and light-source treatments are improving and expanding every year.” Lasers are widely used in operating rooms and outpatient facilities.

“The recovery for patients is usually far less than cold-steel surgery,” says Tanzi, who uses more than 25 different lasers to treat skin conditions. “Over the past five years, we’ve noticed improvements in noninvasive treatments.”

One very promising application for lasers is in photodynamic therapy for skin cancer, says Tanzi. Following the injection of a photosensitizer, a red light is aimed at the cancerous area, and it shrinks or destroys the tumor. Ongoing research is studying ways to improve photodynamic therapy for use fighting cancer.

LumaCare (Newport Beach, CA) uses photodynamic therapy to treat tissue diseases and disorders.

In ophthalmology, it’s eliminating the need to wear glasses. LASIK surgery is a procedure that uses an excimer laser to permanently change the cornea’s shape. In recent years, it has become the primary method used to treat myopia in the United States.

“We’re getting to the point where LASIK is a much better and safer procedure,” says Eliot Lazar, MD, president of ElCon Medical Consulting (Buffalo, NY). “It will continue to evolve over time.”

“It’s a pretty competitive market, and it’s still expanding,” says Greg Aurand, senior medical devices analyst at Zacks Investment Research Inc. (Chicago). “As people become more accustomed to the procedure, and you have some decent data that say it’s not a high-risk venture, you’re going to get market growth out of it.”

IntraLase Corp. (Irvine, CA) took the procedure further and replaced the handheld knife used in the first step with a computer-guided femtosecond laser. “IntraLase’s process, in theory, should cut down the risk of error in hand cutting the cornea, and using a laser to do it should provide a better patient benefit,” says Aurand. Long-term studies are still needed to assess its results.

Progress in surgery and instruments will affect the innovative course of lasers. Applications will continue to expand and will become more prominent in treating severe conditions.

Medical Imaging Technology: The Value Beneath the Surface

Heather Thompson

The Volume CT scanner from Siemens can present unprecedented 3-D images.

The old cliché of a picture being worth a thousand words doesn’t even begin to describe advances in medical imaging. The technology has been a giant since it was invented in the early 1900s. And while those first basic x-rays were impressive, today’s imaging devices have reduced process time from days to mere seconds and transformed the images from shadowy gray figures into fully rendered photos or videos. The images also come in 3-D and full color.

Imaging devices are often broken into five modalities: x-ray, computed tomography (CT), magnetic resonance (MR), ultrasound, and nuclear medicine (or radionuclide scanning).

Although all are used for depicting internal body parts, they each have a forte. Ultrasound, for example, is noninvasive and suited for soft-tissue organs that may be sensitive to radiation. MR is used for many types of soft-tissue imaging and presents sharp-contrast detail between different tissues with very similar densities. CT provides detailed cross-sectional images and diagnostic information for almost all body structures. Spiral CT enables the acquisition of data for 3-D reconstruction. The granddaddy of imaging, the x-ray, is still used today because it is a fast and easy way to assess bone and tissue. Nuclear medicine images show less detail than other types of imaging, but they convey the function of an organ based on how much radiation the organ absorbs.

Scanners can be used to view any part of the body, and they are now branching out to other medical disciplines. Picture archival and communications systems (PACS) are gaining attention because they provide storage, transmission, and display in real time. They can even perform calculations such as counting plaque deposits or measuring bone loss.

The Siemens Axiom Artis enables real-time communication outside the imaging room.

Manufacturers are also improving the speed and capabilities of imaging technology. Recently, Siemens Medical Solutions (Malvern, PA) and Massachusetts General Hospital (Boston) built a prototype for a volume CT scanner.

The area-detector–based scanner uses the Somatom Sensation CT gantry and has a 2-D digital flat-panel detector technology. The new system features volume coverage of 18 cm3 with up to 768 CT slices per rotation.

Although it is not yet ready for human use, the “area-detector CT technology has the potential to introduce important future pathways of CT applications,” says Bernd Ohnesorge, PhD, vice president of global CT marketing and sales at Siemens Medical Solutions.

According to the company, a medical professional using volume CT could directly see the trabecular structure of bone or the dynamic contrast uptake of tumor tissue. It could help identify the composition of atherosclerotic plaque in the vascular system and coronary arteries and spotting microcirculation of the cardiac muscle.

As the technology gets more and more sophisticated, the price of imaging devices will rise. Medical imaging scanners and auxiliary products are expected to reach $10.4 billion by 2009 in the United States.

However, in the end, these imaging devices are so popular because they save money, time, and, of course, patients. Replacing biopsies with images reduces patient discomfort, cost, and time. And in some cases, using imaging can eliminate surgeries and patient hospital stays altogether. Those savings are hard to put a price on.

Wireless Technology: Hospitals and Homes Go Unplugged

Heather Thompson

Once implanted, transceiver chips like the one from Zarlink must conserve energy and alert hospital staff of critical changes in the patient (click to enlarge).

Although consumers have had access to wireless telecommunications devices for several years, hospitals are only now beginning to use the technology for data capture. But for hospitals, wireless applications are more than just a convenience. A mobile connection to data records and real-time updateable information could reduce errors, which could mean the difference between life and death.

Wireless technologies employ data communication systems that link together various users. A wireless local area network (WLAN) can span an office, a building, or even a medical campus.

The technology can be simply explained, although it’s not as simple in practice. Radio and infrared electromagnetic waves transmit the data at a defined frequency. The preferred frequency for medical devices is 402–405 MHz. Base stations integrate data into the facilities’ LAN. They often link to access points or antennas that can be placed strategically to extend the distance between a base station and the end users. The end unit is usually a receiver. It can be almost anything that collects crucial information—a nurse’s personal digital assistant, a radio-frequency identification reader that tracks blood for transfusion, or a patient-monitoring system such as an electrocardiograph machine.

As the technology becomes more sophisticated, companies are fine-tuning ways to use wireless. Companies such as Hospira (New Orleans) are building customizable wireless software into products. For example, the company’s MedNet software has been packaged with drug-delivery systems to help reduce errors.

The Plum A+ wireless system from Hospira defines dose limits and tracks IV drug delivery.

Transceivers (electronics that both receive and transmit data) are also being incorporated into medical implants. Even after they are implanted, the devices can transmit performance data on patient health. Zarlink Semiconductor (Ottawa, ON, Canada) has introduced such a wireless transceiver chip designed specifically to meet medical implant communication service (MICS) standards.

Edward Goffin, communications manager for Zarlink, believes the device will be used at first with pacemakers and defibrillators, but there is potential for other devices, too. “We have a customer who might want to use it for blood glucose meters. Then doctors could implant both the sensor and the insulin into the body and have the whole thing run by the chip.”

Zarlink’s chip transfers data at a rate of up to 800 Kb/sec. “It’s pretty dramatic,” says Goffin. “That’s like going from a dial-up to wireless broadband Internet connection.”

The transceiver operates up to 2 m away from the base station, as opposed to earlier models that needed to be within inches of the base station to work properly. The base station is about the size of a cellular phone. “Patients could have the base station by their bedside or clipped onto their belt,” Goffin says. It connects directly to the necessary hospital computer for monitoring.

The devices can be integrated into imaging centers, laboratories, operating rooms, and now patients. Nearly every point of patient care, and some places patients never see (e.g., administration offices), will eventually benefit from wireless technology.

Computer-Assisted Surgery: The Digital OR

Brendan Gill

Brainlab uses CT and fluoroscopic images to navigate instruments during spine surgery.

Computer assisted-surgery (CAS) is to the surgeon what GPS technology is to the wandering driver. Both technologies have revolutionized navigation, one inside the human body and one on the highway.

CAS, or navigation surgery, uses an image-guided camera and a computer to guide a surgeon’s hands. The camera receives signals from a surgeon’s instruments and then projects the image onto a monitor. This enables a surgeon greater precision and control and results in less trauma and shorter recovery times for patients.

CAS “improves surgery in three key areas: it facilitates more-accurate bone cuts and component alignment, reduces outliers, and enables less-invasive techniques,” says Cameron Georges, director of sales for orthopedics at Brainlab (Westchester, IL). “It also provides quantitative information relative to key variables like ligament balancing, leg length, and range of motion.”

Computers in the operating room have required that medical devices adapt to the higher-tech environment. Companies such as Brainlab and DePuy, Biomet Inc., and Zimmer Inc., all based in Warsaw, IN, are developing medical devices to meet the needs of computer-assisted ORs.

New devices include reference arrays and clip-on adapters. Reference arrays, or small, reflective spheres that transmit information, must be added to medical instruments to be picked up by CAS cameras. Existing instruments are fitted to CAS by using plane adapters that fit in cutting slots or by the use of clip-on adapters, says Georges.

The Vector Vision software from Brainlab can track surgical instruments on a computer screen.

CAS has significantly affected minimally invasive surgery. With CAS, incisions can be smaller and can be made with greater accuracy. However, with smaller incisions comes less visibility for the surgeon.

“The biggest thing is visibility,” says Ryan Shoenefeld, product development engineer in digital surgery at Biomet Inc. “But with CAS, you have the ability to track instruments inside the body with good accuracy. If you’re going to put a hip through a 3–4-in. incision, the system will tell you if you’re putting an acetabular cup in 15° of anteversion. You have the ability to improve outcomes of minimally invasive surgery.”

DePuy is also developing smart implants that can communicate with CAS systems to make up for the surgeon’s reduced visibility. The implants have embedded microchips that communicate with CAS systems. The microchips provide information on whether the implant has moved from the time of surgery, in what direction, and how far. Also in the works at DePuy is a detector that collects information from the implant.

Copyright ©2005 Medical Device & Diagnostic Industry

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