The United States' first-ever face transplant recipients are enjoying post-operative success, according to new data from the Radiological Society of North America (RSNA), as the blood vessels in many of the patients have started to reorganize themselves according to the new host.

Better understanding how face transplants take place, and more importantly, how the patients fare after surgery, will equip scientists with the necessary tools to complete smarter transplants in the future. Many vessels, for instance, find a path posteriorly — or toward the ears — and end up proving vital to doctors during transplantation. Taken together with other findings, these insights may make assessing patient risk, as well as devising surgery planning, much easier.

Face transplantation is an intensely delicate procedure that involves grafting part or all of a donor’s face onto the patient in a surgery formally known as a facial allograft. Doctors reconnect the various networks of blood vessels and veins in the face, ensuring that healthy tissue remains intact and circulation reaches each and every facial extremity. The first successful transplant in the U.S. was performed in March 2011 at Brigham and Women’s Hospital. The patient was a man named Dallas Wiens, who, in 2008, suffered devastating burns from a loose electrical wire. Since then, the Hospital has performed a handful more transplants, which doctors say are all healing nicely.

“All three patients included in this study at Brigham and Women's maintain excellent perfusion, or blood flow, the key element of viability of the facial tissues and the restoration of form and function to those individuals who otherwise had no face,” Dr. Frank Rybicki, study co-author, said in a statement.

Wiens had to suffer through two years of having no identity — a totally featureless face, save for a slit as a mouth — but arrived at the recent conference with his wife and guide dog, and a healthy, recovering face as well. As part of the study, Wiens and the several other patients underwent imaging scans so researchers could accurately see the extent of their healing. The process is called computed tomography angiography (CTA), and it’s used to check for collateralization, or the extent to which existing blood vessels elongate and widen, in order to form new connections.

"The key finding of this study is that, after full face transplantation, there is a consistent, extensive vascular reorganization that works in concert with the larger vessels that are connected at the time of surgery," noted co-author Dr. Kanako Kumamaru, adding that she and her team found the blood vessels tended to course toward the back of the head and lower jaw.

"We have found that since the vessels more commonly associated with the back of the head are critical to maintain the perfusion via vascular reorganization, it is essential to visualize these vessels and determine that they are normal pre-operatively," Kumamaru said. "Patients under consideration for face transplantation have universally had some catastrophic defect or injury."

These defects could greatly complicate a surgeon’s ability to adequately attach a donor face onto the patient. Without the knowledge Kumamaru and her team gained through their study, future surgeons may have potentially missed the crucial checkpoints in determining patient eligibility. What’s more, past studies have suggested that blood vessel reattachment required multiple ending points called anastomosis; however, the team’s findings support the need for only one vascular connection. As Rybicki notes, this could shorten operating time and reduce patient risk.

"Our findings support the simplified anastomosis for full face transplant procedure that, in turn, can potentially shorten the operative time and reduce procedure-associated complications," he explained.

Face transplants are gaining traction, though are still admittedly rare. Only 30 procedures have been carried out successfully since 2005, according to Dr. Branko Bojovich, a surgeon involved in a 2012 face transplant at the University of Maryland Medical Center, the Associated Press reports. Bojovich called the latest findings “very reassuring.”

"We're assuming that these patients will hopefully go on to live productive and long lives," he told the AP.