Researchers at Dartmouth have found a way to make back surgery safer, faster, and more cost effective. MRIs and CT scans can help surgeons identify spine problems such as compressed vertebrae or herniated disks. But finding a clear path to those problem areas is not always straightforward. Tissue and bone not only stand in the way, they can also move during spinal surgery, rendering a CT scan taken prior to surgery much less accurate. To solve this problem, Dartmouth professors from the Thayer School of Engineering and Geisel School of Medicine developed a 3-dimensional, real-time optical tracking system to guide back surgeons as they operate — like a Google Maps for the body.

Registration of CT (computed tomography) and iSV (intraoperative stereovision). CT is transformed to match its surface to iSAV, represented in tracking system coordinates.

Using a complex algorithm and two cameras attached to a surgical microscope, the system produces real-time 3-dimensional digitized images on a monitor. This type of tracked, calibrated stereoscopic camera system has been extensively used in brain surgery but until now has been unexplored for use in spinal surgery. The surgeon can use this new intraoperative stereovision system (iSV) without any additional radiation or labor-intensive marking of key areas on the patient's spine, to match up or co-register with the preoperative CT scan, as some surgeons do today. This new mapping provides more accurate renderings of where spinal implants or other surgical tools and devices need to go during the procedure and is expected to save up to 30 minutes.

A multidisciplinary team at Dartmouth's Center for Surgical Innovation tested the iSV system for accuracy and efficiency while operating on pig spines. Since completing this study, the team has taken its complex system one step further by converting it into a handheld “wand” that the surgeon can pass over the surgical area.

Next up is fine-tuning the system and testing in humans. The National Institutes of Health has provided the Dartmouth team with another round of funding to continue testing. It could be several years, however, before the system becomes widely available for human spinal surgeries.

For more information, contact Callaway Zuccarello at This email address is being protected from spambots. You need JavaScript enabled to view it., 314-862-4300.


Photonics & Imaging Technology Magazine

This article first appeared in the January, 2019 issue of Photonics & Imaging Technology Magazine.

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