Heads Up! Docs Perform First Augmented Reality-Guided Spinal Fusion

Surgeons used augmented reality, which one likened to the heads-up display of a fighter pilot, for the first time in the operating room to perform a spinal fusion.

Three surgeons successfully carried out the first head-mounted display, augmented reality-guided spine surgery at The Johns Hopkins Hospital on June 8, 2020.1 Surgeons used the FDA-approved xvision Spine System to perform spinal fusion in a 78-year-old woman. 

AR guided spine surgeryImage courtesy Camilo Molina, MD

Coinvestigator Camilo Molina, MD, likened the augmented reality surgical technology to having “X-ray vision,” and similar to the display navigation used in the helmets of jet fighter pilots.

The xvision Spine System includes a transparent near-eye-display headset allowing the surgeon to view the virtual trajectory directly on the surgical field in both 2D and 3D without needing to look at a remote screen. Its head-mounted surgical tracking system helps reduce line-of-site obstruction, he said.

Patient Selection and Outcomes

The case involved a standard spinal decompression and fusion of L4 to S1in the patient, who had severe degenerative spine disease. Spinal stenosis and spondylolisthesis contributed to mechanical low back pain and radicular leg pain.

The patient was selected because she had common spinal surgery indications in terms of expected outcomes and clinical challenges, Dr. Molina told SpineUniverse. Shepresented in January and failed to respond to conservative management, including physical therapy and pain management, according to Dr. Molina.

“Not only did the patient meet surgical indications from a general standpoint, but using this type of neuronavigation system in a person of her age who is more prone to having surgical complications was considered beneficial because it allowed us to use a smaller dissection and perform the surgery quickly,” Dr. Molina said. 

The patient “did exceptionally well,” Dr. Molina said. All of the hardware had 100% accurate placement, entirely intrapedicular, as confirmed by computed tomography. No perioperative complications occurred.

Postoperatively, the patient experienced complete resolution of leg pain and was discharged home on hospital day 4 with minimal surgical pain.

Although the surgeons did not time the hardware insertion in the first case, the same surgical team placed 8 screws in 16 minutes in a follow-up case performed on June 10 using the xvision system, Dr. Molina said.

The surgeries were performed by Dr. Molina, who completed his neurosurgery residency and spine fellowship at Johns Hopkins, along with Timothy Witham, MD, Director of the Johns Hopkins Neurosurgery Spinal Fusion Laboratory, and Daniel Sciubba, MD, Director of Spine Tumor and Spine Deformity Surgery.

Camilo Molina, MDCamilo Molina, MD

Dr. Molina is now Assistant Professor of Neurological Surgery, Orthopedic Surgery, and Biomedical Engineering at Washington University School of Medicine in St. Louis. He is also Deputy Director of Spine Innovation at the Center for Innovation in Neuroscience and Technology (CINT).

Augmented Reality Versus Virtual Reality

It is important to differentiate augmented reality from virtual reality in medicine, Dr. Molina said. Virtual reality technology typically involves using a headset that occludes the real-world environment.

The goal of augmented or mixed reality, on the other hand, “is to integrate our visual senses with computer-guided data and mix it in a way that is intuitive and intertwined so that the input is noninclusive of each other,” he said.

Dr. Molina worked with the developer of xvision system to design phantom and cadaveric trials to test and validate the innovations created by Augmedics engineers during their development process. He is the lead author of two papers, one of which is in press, describing cadaveric benchmark data that were instrumental in the FDA’s approval of the system.2,3

“The cyclical design and testing process allowed Augmedics to pivot quickly and develop a technology that is truly surgeon friendly,” Dr. Molina said.

Augmented Reality Spine Surgery: Benefits and Challenges

The headset’s tracking camera—used to locate the trackers placed on tools and the fixed tracker placed on the anatomy--proved invaluable, Dr. Molina said. With traditional 2D surgical navigation systems the remote tracking camera is typically placed at the foot of the bed, outside of the surgical field.

“If a remote camera cannot detect the trackers, the screen goes blank and you lose your navigational guidance,” Dr. Molina explained. The surgical team and OR staff must then troubleshoot the obstruction, which disrupts the workflow and may introduce errors during hardware placement, he said. The head-mounted xvision system allows the surgeon to control the positioning of the tracking camera via subtle changes in head position to avoid or quickly fix any line-of-sight obstructions.

The new technology also eliminates the diversion of attention that occurs when surgeons shift their eyes back and forth from the surgical field to a remote display with 2D navigation systems. Surgical navigation systems, says Dr. Molina, may “predispose surgeons to making a multitude of potential technical errors.”.  

One challenge of using augmented reality in the OR is that surgeons who are used to 2D remote displays require time for their vision to adapt to the 3D mixed reality display, according to Dr. Molina.

And although getting used to the headset may present another challenge, the system “has an incredibly low learning curve,” says Dr. Molina. Surgeons must undergo training and pass a certification exam to be able to be clear to use the system, Dr. Molina explained.

Dr. Molina and his colleagues are currently writing a paper on this first AR-guided spine fusion and are planning future papers describing ideal workflow, technical pitfall avoidance, and new surgical techniques that they envision being performed using this new technology.

Disclosure

Dr. Molina is a consult and senior medical advisor for Augmedics.

 

Updated on: 06/22/20
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