AR System Allows Surgeons to Reconnect Blood Vessels

A team of researchers at Imperial College London (London, UK) at St Mary’s Hospital has demonstrated the use of Microsoft HoloLens headset for performing reconstructive lower limb surgery on patients. The HoloLens is a self-contained computer headset that immerses the wearer in ‘mixed reality’, allowing them to interact with ‘holograms’ which are computer-generated objects made visible through the visor.

In reconstructive surgery, connecting the blood vessels of the ‘new’ tissue with those at the site of the wound is a vital step in order to allow oxygenated blood to reach the new tissue and keep it alive. For this purpose, surgeons generally use a handheld ultrasound scanner, which identifies blood vessels under the skin by detecting the movement of blood pulsing through them, allowing them to approximate where the vessels are and their course through the tissue. However, the Imperial researchers showed how HoloLens could be more reliable and less time-consuming than the ultrasound method of locating blood vessels. By using HoloLens to overlay the images of CT scans, including the position of bones and key blood vessels, onto each patient’s leg, the surgeons could ‘see through’ the limb during surgery. They could also manipulate the AR images using hand gestures to make any fine adjustments and correctly line up the model with surgical landmarks on the patient’s limbs, such as the knee joint or anklebone.

“We are one of the first groups in the world to use the HoloLens successfully in the operating theatre,” said Dr. Philip Pratt, a Research Fellow in the Department of Surgery & Cancer and lead author of the study, published in European Radiology Experimental. “Augmented reality offers a new way to find these blood vessels under the skin accurately and quickly by overlaying scan images onto the patient during the operation.”

The researchers believe that after it is refined, the approach can be applied to other areas of reconstructive surgery requiring tissue flaps, such as breast reconstruction following mastectomy. The researchers will now conduct trials of the technology among a larger set of patients, with procedures carried out by teams at multiple centers. “In future we hope to automate the process further. We can use software to improve the alignment and will attach markers to the patient when they have the scan, with the same markers present during the operation to use as additional points of reference,” added Dr Pratt. “There are a number of areas we would like to explore, and further improvements are needed, but the small case series has shown that for reconstructive surgery, this seems to be a valuable tool in the operating theatre.”

Related Links:
Imperial College London