CHICAGO (AP) — New research on face transplants may help guide future operations for accident victims needing this kind of drastic surgery.

Medical imaging on the nation’s first full face transplant patient and two others shows that new blood vessel networks have formed joining their transplants with existing facial tissue.

That’s according to doctors who presented their data at a medical meeting Wednesday in Chicago.

The same thing typically happens with other transplants and it helps ensure their success. But doctors from Brigham and Women’s Hospital say this is the first time it has been shown with full face transplants.

The transplants all took place at the Boston hospital in 2011.