Spine surgeons seen resisting high-tech navigation devices

Operating on the spine is not brain surgery and remains a physical, hands-on intervention.

Which explains, in part, the continued resistance encountered by Medtronic (Minneapolis) and BrainLab (Feldkirchen, Germany) as they seek to expand sales of surgical guidance technologies from neurological procedures down the spinal column to include not only exceptional interventions for deformities but for more routine repair, restoration and corrections.

At SpineWeek 2008, held here this week, two surgeons faced off on the pros and cons of guidance imaging for pedicle screw placement in a session jointly sponsored by the European Association of Neurosurgical Societies (EANS) and AO Spine, a division of Arbeitsgemeinschaft für Osteosynthesefragen (the AO Foundation).

A poll conducted ahead of what the organizers called “a duel and not a debate,” showed the audience was 80% European and made up equally of neuro and orthopedic surgeons, which skewed the response, showing that 38% use navigation technology regularly.

Serge Bellon, the head of navigation products for Medtronic in Western Europe, told Medical Device Daily that realistically, fewer than 15% of spine surgeons in his region use guidance assistance with pedicle screw placement. So it was encouraging to see that 29% of the group said they planned to start using it and another 15% said they were interested in experimenting with it.

Heading the opposition was Jesus LaFuente, a surgeon at Hospital del Mar (Barcelona, Spain), who while acknowledging the “impressive” nature of the technology, pointed out that it was created for the brain, where it is essential to localize and plan an approach to the target. “There is only one way to reach the target for a pedicle screw, so we have to ask if it is really necessary,” he said. Using navigational assistance for precise placement of the screws, which are vital for holding in place the heavy metal that fuses vertebrae, is time-consuming, forcing longer wound exposure, LaFuente said. He added that the reference procedure to align the real-world landmarks on an implant with the virtual points recorded for the software also causes the wound to be enlarged, creating greater exposure for the patient.

Fuentes said that even after he had passed the learning curve, the procedure took just under three hours compared to only one hour for the traditional approach.

“The only clear advantage,” he said, “is reducing to just two the number of X-rays required during the procedure,” compared to the continual exposure to fluoroscopy in conventional surgery. LaFuente concluded after his experience that real-time guidance “is not helpful for degenerative spine procedures” and that the medical literature shows little difference in outcomes for patients for what he called “free-hand versus navigation.” An unabashed supporter of navigation support was Frank Kandziora, MD, who in January left Charité University Hospital (Berlin) to set up the Center for Spine Surgery and Neurotraumatology at the BGU Trauma Hospital (Frankfurt, Germany).

After asking the audience to stand, he then asked any surgeon who had not misplaced a pedicle screw to remain standing and was satisfied he had taken his best shot in the duel, as no surgeon was left standing. Kandziora said medical literature shows the rate of misplaced screws, which can result in a range of problems from minor discomfort to major impairment if the screw pierces the spinal cord, can vary from 4% to a shocking 40%. Yet in neurological procedures where navigation is universally used, he said, when pedicle screws are placed as part of the intervention, studies show a consistent and narrow range for misplacement of between 2% and 5%. Kandziora translated the statistics into harsher terms. Where only one screw in 1,250 is misplaced using navigation, the odds are closer to one-in-50 for spinal free-hand. “That would mean that in a hospital with a reasonable volume of procedures, five patients a year are suffering to some degree from misplaced screws,” he said.

Kandziora added that a surgeon cannot turn to navigation assistance occasionally when confronted with severe deformities or some kind of special problem to be solved. The skills and experience need to be acquired during routine practice in order to be able to call upon the technology for specialized interventions. In a poll of the audience, the top reasons for not using computer-assisted guidance for screw placement was the expense buying the equipment and the time required for the procedure. The head of sales for BrainLab in German-speaking markets, Christoph Beisse, told MDD the cost of the suite of radiology equipment and software for a spinal navigation system runs between €110,000 and €150,000 ($157,000 and $235,000).

BrainLab next month will introduce the eighth generation of its system that is easier to use, he said. “We have been successful with university and reference hospitals among specialists,” he said, adding that the company has an installed base of 2,000 units worldwide. “Now we are working toward the wider base of practice,” Beisse said. Medtronic’s Bellon said the company’s focus for the StealthStation is neurosurgery, “and necessarily this means our customers are the large university hospitals.” Yet two-thirds of procedures performed with the equipment touches the spine, either in combination with a neural intervention or a straight-forward spinal repair or correction. The installed base for Medtronic worldwide is 2,500 units since the units were launched 10 years ago.

“This is not a new technology and it is not the latest hype in trauma surgery,” said Kandziora. “There are a lot of companies who offer nicely developed systems, and it has been clearly established that navigation increases safety,” he said, “But it does require an investment, both of the surgeon’s time and money.”

Source: JOHN BROSKY Medical Device Daily European Editor

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