Until now, surgeons had to memorize the precise location of important blood vessels in organs and where tumors were likely to be found. But, a new app for tablet computers developed by Fraunhofer MEVIS research institute in Bremen, Germany, could help surgeons reduce the rate of complications during operations by helping them to visualize the vasculature during surgery.

On August 15, a surgical team at a hospital in Hamburg successfully tested the app during a liver operation. Liver cancer surgery may take several hours because the organ is complex and hosts a branching vessel structure through which one and a half liters of blood flow every minute. If a surgeon makes a cut in an inappropriate place, this puts the patient at risk of severe blood loss. In addition, doctors must ensure that the patient retains enough organ volume for survival and that this volume is sufficiently supplied with blood. To accomplish this, doctors need to know as accurately as possible, both before and during an operation, where blood vessels inside the organ are located.

The new tablet app from the Fraunhofer Institute for Medical Image Computing MEVIS in Bremen is based on the established MEVIS software for liver operation planning that is employed in clinics worldwide. Based on 3D x-ray images, the software can reconstruct the locations of blood vessels in the liver for each patient. Before an operation, surgeons can then precisely plan how and where to place the scalpel to most effectively remove a tumor.

However, doctors usually have little opportunity to view the software images during surgery and compare the surgical situation with planning data. Some surgeons even print out images to take into the operating room. With this app, the entire data and images can be shown directly at the operating table. And, with the tablet’s integrated camera, the tablet could film the liver during the operation. The app then can superimpose the planning data showing the vessel system to determine whether the surgery has gone according to plan.

By simply marking the touchscreen, doctors can measure the length of a vessel to be removed. After the surgeon removes certain vessels, he can remove them on the app screen with a virtual eraser. The separated vessels disappear from the screen and let the doctor view underlying structures. And, if during the operation, additional vessels must be removed, the app calculates which parts of the liver will no longer be sufficiently supplied with blood, allowing the surgeon to better estimate whether the remaining organ volume is large enough for the patient to survive.