A Close-Up Look at Computer-Assisted Navigation in Spine Surgery

CT navigation has been a game changer for minimally invasive spine surgery. Get tips on navigating with the O-arm from SpineU’s expert.

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When you were a child, did you ever want X-ray vision like Superman? As a spine specialist, you have access to the next best thing: actual X-rays (and other forms of imaging).

CT navigation in spine surgeryCT navigation has been a game changer for many surgeons. Are you one of them?

Spine surgery is rapidly becoming less and less invasive, thanks in part to better imaging techniques. No longer are large incisions always necessary to see inside the area upon which you’re operating. While it’s not exactly X-ray vision, CT navigation might just be the next best thing, especially for some procedures such as placing pedicle screws.

A Brief History of Computer-Assisted Navigation

Early advancements in medical imaging paved the way for the development of changes in imaging coupled with computational technology. In 1895, German physicist Wilhelm Roentgen discovered Roentgen rays—known today as X-rays. Then in 1940, X-rays became easier to see with the help of image intensifiers, which allowed for fluoroscopic images to be captured and viewed under dimmer lit settings (such as an operating room).

A turning point in surgical imaging is the development of the C-arm in 1955, which transformed the use of the X-ray during procedures. The C-arm’s mobility made it ideal for intraoperative use. It lessened the need for large incisions by increasing visualization of the patient’s anatomy prior to making incisions.4 Ultimately, it improved the ability to accurately place pedicle screws in the spine.

In 1971, the first computed tomography (CT) scanner was created by Godfrey Hounsfield and colleagues, which produced cross-sectional (tomographic) images from X-rays.  Then in 1998, the primer of four-row detector CT scanners allowed for 3-dimensional reconstruction occurred. This drove the rapid development of current-day navigational technologies.

In turn, these advancements (among others) allowed for the development of advanced computer-assisted navigation: the O-arm™.

Procedures That Best Utilize Computer-Assisted Navigation

The O-arm™ is a mobile X-ray system that is designed to assist physicians in need of 2-D fluoroscopic imaging and 3-D imaging for patients of all ages over 60 lbs. and with an abdominal thickness > 16 cm in real-time during a procedure. Among its other achievements, it allows surgeons to achieve As Low As Reasonably Achievable (ALARA) and provides an opportunity to reduce dose to both surgeons and staff.

Additionally, it effectively streamlines the workflow process by eliminating the need to send a patient to radiology prior to a procedure.

Lali Sekhon, MD, PhD, MBA, a board-certified (FRACS) and double-fellowship trained spine neurosurgeon and pain care specialist with the Reno Orthopedic Center, has fully adopted the use of the O-arm™ and recommends the device for several procedures. “This technology is ideal for anywhere that a screw trajectory is variable and needs accuracy,” says Dr. Sekhon. “Generally, because a navigation reference pin needs to be placed into the iliac crest or onto a spinous process clamp, this navigation technique is best suited to posterior and sometimes lateral procedures.”

Indications for the most ideal use of the O-arm™ include:

  • Placement of pedicle screws
  • Transforaminal lumbar interbody fusion (TLIF)- guiding disc space preparation and implant placement
  • Iliac fixation
  • Lateral fixation
  • C1/2 fixation and subaxial fixation as needed             

“The 3-D visualization that the O-arm™ offers is ideal for difficult cases, such as revisions. It overcomes several obstacles, such as obesity, broad shoulders, and osteopenia that make it hard to see on X-rays,” Dr. Sekhon says. “In can also be used to guide bone work for decompression and disc prep.”

Navigating With the O-arm™

With regards to the best way to handle the O-arm™, quick intraoperative acquisition and reacquisition is the key to its success. “Using navigation does not eliminate tactile feedback. In addition, it is better suited to open procedures and mini-open, is forgiving with tissue retraction, and allows subtle redirection of trajectories in real-time (e.g., The O-arm™ will follow the cancellous bony channel in the pedicle and surgeons can allow it to lead and subtly redirect the pathway under their guidance. A robotic screw hole for example is a hole in space. Once set, there is no real-time readjustment),” says Dr. Sekhon. “You can easily palpate screw holes, for example.”

“Married with the power hand drill it allows the surgeons to combine their knowledge of anatomy with tactile real-time feedback and adjustments,” says Dr. Sekhon. “When we went from fluoroscopy to CT navigation, we went from a three to  a nine  in terms of standard pedicle screw insertion for ease, reproducibility, and reliability.”

Today’s computer-assisted navigation such as the O-arm™ has built upon years of technological advancements in medical imaging to provide surgeons with precise real-time feedback during procedures, such as minimally invasive surgery (MIS). By leveraging these improvements in imaging, spinal technology has and will continue to rapidly grow and provide better outcomes for patients for years to come.

Updated on: 07/13/21
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Lali Sekhon, MD, PhD, FAANS, FRACS, FACS

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