Image-Guided Surgery

A whirlwind of technological advances and a range of purchasing decisions have forced American hospitals and healthcare institutions into a lottery atmosphere where it’s risky to hedge their bets.

Hospitals that invest their money in image-guided surgery (IGS) systems are wagering on cost savings related to more accurate surgeries and briefer recovery times for patients. The potential payouts rely on everything from fewer malpractice suits and heightened community esteem to increased revenues from previously inoperable conditions.

Medtronics Inc (Minneapolis) is the worldwide leader in the $110 million-a-year industry that also includes such manufacturers as GE Medical Systems (GEMS of Waukesha, Wis), Siemens Medical Solutions USA Inc (Malvern, Pa) and BrainLAB Inc (Munich, Germany).

Because the capabilities of systems vary widely, the cost range does, too. A very simplistic version can be purchased for about $100,000, while a state-of-the-art IGS system with an array of modules will set a facility back $400,000 or more. The average system costs about $200,000 and has a life span of between 3 and 5 years.

“If you interview surgeons, they’ll tell you that image-guided navigation is the standard of care,” says Karim Karti, VP of global surgery marketing and product management for GEMS. “Some hospitals are afraid of saying so, but that’s because they’re afraid of the consequences.” If an institution agrees that IGS is the standard of care, it would be hard pressed to defend an undesirable outcome from a procedure in which a surgeon didn’t use the technology. In actuality, however, most neurologists today are using navigation.

Industry insiders might disagree as to whether IGS has become the standard of care in neurosurgery and orthopedics already, but one thing seems certain: If it isn’t yet, it soon will be. And not just in delicate neurosurgery, but in nearly every surgical specialty. And while healthcare professionals squirm under ever-increasing pressure to improve quality and contain costs, the touted benefits of IGS systems offer another step forward in that quest.

Even dentists are getting into the act. “That seems to be a niche market at the moment; only two or three companies are doing image-guided dental surgeries,” says Naissan Vahman, a senior analyst in the medical hardware division of Millennium Research Group (Toronto).

But in a medical community that seems to embrace advanced technology at warp speed, what could hinder the widespread acceptance of IGS? According to Vahman, manufacturers need to prove the clinical benefits for both surgeons and patients. They need to decrease the complexity of the systems and boost ease of use. Also, the systems need to be manufactured to provide real-time 3-D imaging of the internal anatomy of tissue. The manufacturers are doing all three.

IGS might be a new technology in the realm of minimally invasive surgical procedures, but it’s evolving quickly. And combining it with minimally invasive surgery creates an apparently happy marriage.

With minimally invasive approaches, surgeons perform a variety of surgical procedures via natural body openings or small incisions. The result: access to difficult-to-reach anatomy, less patient trauma, shorter hospital stays, quicker recovery, and less pain. Until now, the trade-off for smaller incisions has been decreased visibility.

Before IGS systems were developed, minimally invasive surgery allowed surgeons to see only the anatomical surfaces visible from the end of an endoscope. The surgeon had to rely on his knowledge and memory—not to mention a little bit of guesswork—to determine the location of vital structures outside his field of vision.

IGS systems combine tracking technology with high-speed computers and specialized software to follow the movement of surgical instruments on a screen that displays images of the patient’s actual anatomy.

“The difference between image-guided systems and traditional mechanical instruments is like the difference between using GPS technology and paper maps,” says Dr Michael Swank, an orthopedic surgeon who became the first in the United States to perform a knee replacement using BrainLAB’s VectorVision system just 2 years ago. He has since performed more than 160 similar operations. “It allows us to not just make inferences; it actually tells us where we are.

“Much of reconstructive surgery involves multiple steps,” Swank continues. “If, with each step, I can make the results perfect, then the accumulation of errors goes away. I can see immediately when something is 1? or 2? off; then I can compensate on the next step.”

This ability allows surgeons to perform fewer revision procedures, because they’re able to achieve pinpoint accuracy the first time. And this accuracy creates alluring incentives for hospitals that are looking to maximize reimbursement. As IGS becomes more widely established—and, thus, more widely reimbursed—revision surgeries become suspect. Why would an insurance company pay for a surgeon to perform two surgeries, including related lab tests, hospital stays, and personnel, when the surgeon could complete the procedure accurately with one image-guided surgery?

A Real-Time Revolution
“Navigation started years ago with cranial surgery,” GEMS’ Karti explains. “Surgeons adapted quickly to the technology to do mostly tumor surgery. It allowed them to do a smaller incision in the skull and get to the tumor. There used to be a lot of planning by looking at CT scans and MRIs for the best angle. But once you register the patient with navigation equipment, you are able to see—live—the direction of the tool and whether it reaches the tumor. Obviously, it gives [surgeons] a productivity tool, but it’s also something that allows them to make a smaller incision.

“The technology went to ENT [ear, nose, and throat] for sinus surgery,” he continues. “It focused on sinus surgery, because it used to be a totally open procedure; they used to cut the nose open. Then, with the introduction of endoscopy, the challenge was that you didn’t really understand where you were. And as you’re getting closer to the brain, you have some significant safety issues. The navigation technology allowed the surgery to have a visual context to where they are and where the instrument is. It allows them to always be within 1 mm or 2 mm of accuracy on a consistent basis. It significantly reduced the associated complications.”

Today, even patients are familiar with the concept of minimally invasive surgery.

“Minimally invasive surgery is obviously a big buzzword,” Swank says. “But when you’re making smaller incisions, you’re taking away visual cues from the surgeon. Image-guided technology puts them back. I can put percutaneous screws in a patient’s spine without making holes in his back. That used to require a 6-inch slice and 2 hours of surgery, where I had to damage the muscles so I could see the bones that I was putting the screws in. Now I can do all of that with a small incision, and the patient can go home the next day.”

When hospitals and surgical practices consider an outlay of several hundred thousand dollars, they need to understand why.

“They might ask, ‘Why bother?’ ” Swank agrees. “ ‘I can do this procedure in 45 minutes. Why should I take a little more time?’ The question is, what’s the price of perfection? You might not always be right, but this [procedure] is always right.

“The nice thing about navigation is that it allows the average surgeon to get immediate feedback, so that’s very powerful,” he continues. “Computers are impartial. They will tell you, ‘The cutoff is 5?.’ The technology is designed to reduce the variance so that what’s produced is good every single time—and not just good, but as perfect as it can be. Techno-logy is about being as perfect as we can be.”

System Components
IGS systems are comprised of several features: a tracking device or camera; the hardware and software components; and a registration device, which is there to align the patient’s image with preoperative images.

The systems vary in the way they structure the modules. Manufacturers differentiate themselves with technology and the compatibility with available modalities. Some are

fluoroscopic-based neurology models, and others are CT-based. It’s important for facilities to distinguish which service and tech support features are priorities.

Another matter of preference is electromagnetic (EM) or optical cameras. “Some people say that EM cameras are better because they don’t have line-of-sight issues,” says the Millennium Research Group’s Vahman. “In optical tracking systems, certain movements might interfere and distort the image on the computer. But proponents of optical cameras argue that metallic instruments might affect accuracy issues with an EM system.”

Customers of GEMS’ equipment have made their preferences clear.

“We believe that electromagnetic is the way to go in the future,” Karti says. “From a set-up, footprint, and workflow point of view, it’s superior to optical. You have a line-of-sight issue with optical. If you have people all around, you won’t be able to see. With EM, you don’t have that problem.”

Navigating Toward New Uses
“Today, we’re focusing on the spine,” Karti says. “Traditionally, back surgery is performed openly, with a significantly large incision in the back. You cut through the muscles. Recovery could take anywhere from a few weeks to a few months. We’re trying to enable more minimally invasive procedures. When you don’t have a lot of direct feedback of anatomical landmarks, then you have to be open. With navigation, you’re able to see where the instruments are and where they’re going. You don’t need the landmarks that you did before. This process is evolving, and we think the spine community is also focusing on it in a big way.”

Karti believes the true focus is on patients recovering more quickly. He even envisions a time when back surgery will be performed as an outpatient procedure. “People are looking at the best way to make it work, and navigation is the best way,” he says. “In the future, we’ll have all kinds of applications, including pain management and the whole biopsy area, that could be enabled quickly with navigation. You could do biopsies in a much easier way that’s safer for the patient, too.”

C’ing More
The growth in minimally invasive surgical procedures is helping to drive the popularity of C-arm technology. Through new hospital construction, ambulatory surgery centers, pain-management clinics, and physicians’ medical and group practices, an aging population is once again demanding the latest and greatest.

“What’s really fueling 3-D imaging is these minimally invasive procedures,” says Michael Caro, surgery product manager for Siemens Medical Solutions USA Inc. “Spinal surgery and pain management are two examples of specialties where 3-D has dramatically raised the standard of care.”

Worldwide, Siemens has installed almost 300 3-D C-arms, called the SIREMOBIL Iso-C3D, at about $200,000 each. Siemens is the only manufacturer yet to succeed in bringing a 3-D C-arm to market.

“We’ve had surgeons make the point that they see this becoming the eventual gold standard of care,” Caro explains. This gold standard relies on a piece of hardware shaped like a “C.” At each end of the C are imaging components that take a series of 2-D images while the C rotates 190? around the anatomy. Those 2-D images are reconstructed with a PC into 3-D images on an adjacent computer screen.

The computerized process is completely automated, and surgeons have immediate access to the images and the depth perception that the images allow. Surgeons can scroll through 256 slices—as thin as 0.5 mm or less—and click with a specialized sterile mouse on any view to focus on a region of interest. Then the surgeon can even manipulate that view to any angle at any plane.

This technology offers real-time tracking of the data set, and it comes with an option that allows direct integration with surgical navigation systems; Medtronics and Brain-LAB have both received FDA clearance to directly DICOM-connect with the Iso-C3D.

“Spine surgery is an interesting specialty,” Caro says. “Both neurosurgeons and orthopedic surgeons have found 3-D to be a phenomenal benefit. Where it becomes of particular value is during pedicle screw placement. You need to place these screws very precisely.” Undoubtedly, imprecision carries high costs, as damage to the spinal canal, nerves, cord, or arteries is disastrous.

“If it was me, I wouldn’t want anybody thumbing through the dark,” Caro explains. “I’d want to have the latest and most state-of-the-art kind of surgery. It’s a way of checking hardware placement and patient anatomy before the patient leaves the operating room. Otherwise, [the surgeon] performs the procedure, places the hardware, and positions the anatomy [in the way he] thinks it should be placed. He then closes up and sends the patient to the radiology department for a postoperative CT or MR scan. Then the surgeon either says, ‘It looks good,’ or ‘Oops!’ Then he’s wheeling the patient back to the OR and going through the ordeal of another major surgery to correct the placement.”

The benefits translate into technology that hospitals can market to their patients. The convenience and improved quality of care are important enough to justify a cash outlay, which, Caro says, is recouped in myriad ways.

“They don’t have to rely as much on their CT scanner,” he says. “Even if the scanner is in-house, it’s fairly expensive to run. It represents additional time and effort. We’ve seen hospitals and surgical centers with C-arms decreasing their staffing needs by up to one full-time employee—they no longer need a trained person to run the CT scanner.”

Bridging the Training Gap
“Training is a popular request,” says GEMS’ Karti. “Most of the academy institutions in the United States have adopted navigation as a way of teaching new surgeries. We either take surgeons to a workshop, or we perform a live demonstration in a hospital. Most of the training we offer is on-site.”

But leaving the training up to manufacturers is risky. “Education and training are huge issues,” Swank says. “They’re probably two of the biggest problems. As orthopedic surgeons, we spend 5 years in orthopedics, learning from other surgeons. Then you go out on your own, and that’s it. We need to have models of training and education that improve the results for patients.

“They need to see how it works, to practice, to see it again, and to then do it,” he continues. “I feel a responsibility to the patients who have a procedure by a surgeon I train. If I make it look too easy, then the surgeon might think it is easy.” Swank admits that the procedures can be simple, but they can be made easier with navigation. He also explains that about 90% of all hip and knee surgeries are performed by surgeons who do fewer than 20 such procedures per year.

“Navigation isn’t the standard of care, but I believe it will be in 10 years,” he says. “We can do so many things that we couldn’t do before. The problem is, surgeons don’t always know how to interpret all of the information. We’re trying to decide how to incorporate training so that everyone can understand the procedures and do them well. The whole system is being set up now.”

A Minimal Glimpse of the Future
According to the Millennium Research Group’s Vahman, the coming years will bring expansion of new applications and uses for IGS systems. “Other interesting things might be to see whether or not hospitals will purchase the systems for just one department,” he says. “Will they buy more systems with fewer modules or fewer systems with more modules? Will the manufacturers target individual departments, or will they simply go after hospitals?

“What we foresee happening is an expansion of indications in image-guided surgery,” he continues. “There will be models for soft-tissue use. In the future, systems will be used for everything from cardiology to gynecology and oncology. The first samplings should be this year or the next.”

As with all rapidly advancing technology, the future of IGS remains to be seen. Odds are patients and the medical community will share the winnings.

Holly Celeste Fisk is a contributing writer for Medical Imaging.