Following severe trauma, patients may have tissue damage or open wounds that require reconstructive surgery using fasciocutaneous flaps. These flaps of tissue, which are taken from elsewhere on the body and include the skin and blood vessels, are used to cover the wound and enable it to close and heal properly. A vital step in the process is connecting the blood vessels of the new tissue with those at the site of the wound, so oxygenated blood can reach the new tissue and keep it alive.

(Top) AR models reveal the patient's bones and blood vessels; (bottom) the surgeon's view. (Images: Philip Pratt et al. Eur Radiol Exp, 2018; Microsoft HoloLens ©Microsoft)

Surgeons used Microsoft HoloLens headsets while operating on patients undergoing reconstructive lower limb surgery. The HoloLens is a self-contained computer headset that immerses the wearer in mixed reality, enabling them to interact with holograms — computer-generated objects made visible through the visor.

The technology was used to overlay images of CT scans — including the position of bones and key blood vessels — onto the patient's leg, in effect enabling the surgeon to “see through” the limb during surgery.

The approach can help surgeons locate and reconnect key blood vessels during reconstructive surgery, which could improve outcomes for patients. Using the HoloLens, surgeons look at the leg and essentially see inside it at bones and the course of the blood vessels, and can identify exactly where the targets are located.

The standard approach for this element of reconstructive surgery has been the use of a handheld scanner that uses ultrasound to identify blood vessels under the skin by detecting the movement of blood pulsing through them, enabling the surgeon to approximate where the vessels are and their course through the tissue. 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.

These models are fed into specially designed software that renders the images for the HoloLens headset, which in turn overlays the model onto what the surgeon can see in the operating theater. Clinical staff are able to manipulate these AR images through 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 ankle bone.

The technology could potentially help reduce the time a patient spends under anesthesia, and reduce the margin for error. Once refined, the approach could be applied to other areas of reconstructive surgery requiring tissue flaps, such as breast reconstruction following mastectomy.

For more information, contact Ryan O‘Hare at This email address is being protected from spambots. You need JavaScript enabled to view it.; +44 (0)20 7594 2410.


Tech Briefs Magazine

This article first appeared in the August, 2019 issue of Tech Briefs Magazine.

Read more articles from this issue here.

Read more articles from the archives here.