The software, which models the effect of the different incisions surgeons can make, is designed to help minimise the disfigurement some patients can suffer after a major operation.
"The system allows the user to see the results of a particular wound closure and edit the cutting path to explore different options," says Steve Pieper, a computer scientist at the Brigham and Women's Hospital's Surgical Planning Laboratory in Boston who helped create it.
When surgeons remove a facial tumour, for example, they have to cut the skin to create flaps that they can pull back to reveal the tissue below. Because skin can bunch or stretch unpredictably, and surgery can interfere with the muscles and other soft tissue, it is difficult to predict what will happen after the skin flaps are rejoined during the operation.
Pieper began tackling this problem more than 10 years ago with a program that predicted how a human face might look after surgery. But this used a generic face, and did not take account of the unique structure of soft tissue beneath the surface of different individuals' skin.
Now Pieper, together with colleagues from Digital Elite in Los Angeles, a company that specialises in facial modelling for the film industry, has produced software that solves this problem by basing its calculations on data from MRI scans of the patient undergoing surgery.
The scans show the structure of the epidermis, the dermis and the subcutaneous fat, the three layers closest to the skin surface. This is combined with a 3D scan of the skin surface to give the external shape of the face. These layers have an important effect on the way the face looks and the forces the skin is put under when it is cut and as it is knitting back together.