In a recent case study published in European Radiology Experimental, surgeons at St. Mary’s Hospital in London used Microsoft HoloLens to overlay images of CT scans onto patients' legs during reconstructive lower limb surgery. 

"We are one of the first groups in the world to use the HoloLens successfully in the operating theatre," Dr. Philip Pratt, a research fellow in the department of surgery and cancer at Imperial College and lead author of the study, said in a statement. "Through this initial series of patient cases we have shown that the technology is practical, and that it can provide a benefit to the surgical team. With the HoloLens, you look at the leg and essentially see inside of it. You see the bones, the course of the blood vessels, and can identify exactly where the targets are located.”

The HoloLens augmented reality headset gave surgeons had the ability to see the position of the bones and key blood vessels through the limb during surgery. Typically, the HoloLens is only available to developers in the UK, a statement noted. 

The trial included six patients aged 27 to 85, all of whom underwent reconstructive surgery.

Before the surgery, patients received CT scans to map the structure of their legs, including the position of their bones and the location and course of their blood vessels. A radiologist translated the scans into bone, muscle, fatty tissue, and blood vessel, and then loaded it into software that created a 3D image. These images were transferred to software that would be seen through the HoloLens. 

During the surgery clinicians could manipulate the AR images with hand gestures, allowing them to adjust and line up the model with the patient's anatomy. 

“It was possible to construct valuable AR models from [CT angiography] scans of the lower leg perforators and to use these models in a series of reconstructive surgeries over six cases,” authors of the trial wrote. “The HoloLens proved to be a powerful tool that has the potential to reduce anaesthetic time and morbidity associated with surgery as well as to improve training and provide remote support for the operating surgeon.”

During reconstruction surgery clinicians need to attach a piece of skin taken from somewhere else in the body to the wounded area. Surgeons then need to connect this skin to the blood vessel so the that it is oxygenated and the blood can reach the new tissue. Typically, clinicians use an ultrasound to identify blood vessels under the skin by detecting movement of blood pushing through them, according to the statement. 

AR let surgeons find the vessels by putting the scans over the patient's body during the operation. 

"The application of AR technology in the operating theater has some really exciting possibilities," Jon Simmons, a plastic and reconstructive surgeon at Imperial College, said in the statement. "It could help to simplify and improve the accuracy of some elements of reconstructive procedures. While the technology can't replace the skill and experience of the clinical team, it could potentially help to reduce the time a patient spends under anesthetic and reduce the margin for error. We hope that it will allow us to provide more tailored surgical solutions for individual patients.”

Using HoloLenses for surgery is not a new idea. In May, medical navigation technology and mixed reality company Scopis launched a new tool to enhance visibility when performing spinal surgery using the AR device.