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Reducing Spinal Surgery Errors with Software

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LevelCheck software clearly labels each vertebra in this X-ray image taken just before a patient's spinal surgery. Note the pin to the left of L3. L and S stand for the lumbar and sacral regions of the spine, respectively. (Photo courtesy of Johns Hopkins Medicine.)

LevelCheck software clearly labels each vertebra in this x-ray image taken just before a patient’s spinal surgery. Note the pin to the left of L3. L and S stand for the lumbar and sacral regions of the spine, respectively.
(Photo courtesy of Johns Hopkins Medicine.)

To avoid surgeons mistakenly operating on the wrong vertebra, Johns Hopkins researchers have developed a software program that works seamlessly with currently available procedures to assist a surgeon’s determination of which vertebra is which. Results from its first clinical evaluation show that the LevelCheck software achieves 100 percent accuracy in just 26 seconds. The article was published recently in the journal Spine.

“Wrong-level spine surgery is never meant to happen,” says Jeffrey Siewerdsen, PhD, a professor of biomedical engineering at Johns Hopkins and a member of the Armstrong Institute for Patient Safety and Quality. “But it happens nearly four times a week in the US.”

Before a standard spinal operation, patients receive a diagnostic CT or MRI scan that the surgeon uses to plan the surgery. Once the patient is on the operating table, often days later, the surgeon typically counts down from the skull or up from the tailbone to determine which vertebra to operate on, often marking the patient’s anatomy with thin metal pins. These pins are visible in an x-ray image taken in the operating room to verify the target site. But the doctor’s initial planning on the preoperative scan is not visible in the x-ray image, leaving room for error, particularly when working on challenging cases exhibiting missing or extra vertebrae, a loss of anatomical landmarks from previous surgeries, or other anomalies.

LevelCheck uses a standard desktop computer outfitted with a graphics processing unit, commonly used for video games, to align a patient’s 3D preoperative CT image with the 2D x-ray image taken during surgery. The result is an x-ray image showing the pins that act as landmarks for the surgeon, overlaid with the planning information from the CT scan.

“LevelCheck does not replace the surgeon’s expertise. It offers helpful guidance and decision support, like your GPS,” Siewerdsen says.

To test its accuracy, the team analyzed preoperative and intraoperative images of 20 consecutive patients who had undergone spine surgery. By shifting the images, they simulated 10,000 surgeries and measured how long the software needed to correctly line up the images 100% of the time: only 26 seconds.

“This study is the first to demonstrate that LevelCheck works with real patient images,” Siewerdsen says. “It shows that the software can deal with challenges like changes in patient anatomy and the presence of surgical tools in the x-ray image.”

Sheng-Fu Lo, MD, evaluated the results to find what factors can cause the software to fail. “The software doesn’t always get it right if it is stopped early,” Lo says, “but given 26 seconds or more, LevelCheck found the right level every time.”

[Source: Johns Hopkins Medicine]