HoloLens Gives Surgeons X-Ray Vision During Patients’ Operations

At the Imperial College London at St. Mary’s Hospital, researchers have conclusive data showing how surgeons used Microsoft HoloLens mixed reality headsets to see through the legs of patients undergoing reconstructive lower limb surgery.

By digitally overlaying patient-specific images of CT scans, surgeons could effectively see through the limb during surgery. What they saw was a 3D map of the interior—the position of bones and blood vessel structures—to help them navigate the “terrain”, so to speak. (Image courtesy of Philip Pratt et al. Eur Radiol Exp, 2018.)

Research indicated that employing the HoloLens-oriented approach can assist surgeons in locating and reconnecting crucial blood vessels during reconstructive surgery, improving the results by decreasing the probability of an error based on incomplete approximations.
Dr. Philip Pratt, lead author of the study and a Research Fellow in the Department of Surgery & Cancer, published the research in European Radiology Experimental.

In the published research study, Dr. Pratt wrote about the experience, saying that reconstructive lower limb surgeries can be very complex due to the nature of damage caused by severe traumas, such as car accidents. When patients incur tissue damage or have open wounds that necessitate reconstructive surgery, using fasciocutaneous flaps (tissue cut from other places on the body to repair the damage) necessitates knowing where the blood vessels can connect from the flaps to the areas on the damaged lower limbs.

Currently, the standard approach for connecting fasciocutaneous flaps to damaged lower-limb tissue involves the use of a handheld ultrasound scanner. The scanner detects blood vessels under the skin by tracking the movement of blood, giving surgeons not a precise 3D map of the vessels, but a close approximation of their location.
Dr. Pratt reported that his team can see the blood vessels underneath the skin of the lower limb by overlaying CT scan data. This data provides images of everything, from the structure of the limb to the precise location and structure of the patients’ blood vessels.

Dr. Dimitri Amiras is a consultant radiologist at Imperial College Healthcare NHS Trust (ICHNT) who segmented patient-specific scan data into blood vessels, fatty tissue, muscle and bone into an intermediary software that rendered the images for HoloLens. It was Dr. Amiras who had the idea to overlay CT scan data through HoloLens directly in the operating room at St. Mary’s Hospital, which is a major trauma center. The evolution of procedures is pretty remarkable: first, doctors had to rely on rough approximations from 3D CT scan data. Now, with the new digitally overlaid CT scan data, the HoloLens provides surgeons with accurate locations of the blood vessels, and virtual arrows guide the surgeon making incisions.

Plastic and reconstructive surgeon Dr. Jon Simmons notes that the data preparation does take a lot of time, but he sees the currently time-expensive data preparation transforming into a process that will be increasingly automated.

The researchers and medical team noted that they were among the first to successfully use Microsoft HoloLens in the operating room and were optimistic about the results and indications for others around the world. They are now planning to trial the Microsoft HoloLens CT Scan overlay procedure on a broader set of patients. The hope is that it could be used in many more diverse types of surgeries.