Kneatayle Hope and Adeline Faith Mata are even more unique than your average identical twins. The Texan girls were born conjoined, which only happens about once in every 200,000 live births. And they were very conjoined.

"This case was unique in the extent of fusion," Rajesh Krishnamurthy,  chief of radiology research and cardiac imaging at Texas Children's Hospital, said in a statement. "It was one of the most complex separations ever for conjoined twins." Krishnamurthy and his colleagues presented a study on the case Wednesday at the Radiological Society of North America's annual meeting.

The girls had thoraco-omphalo-pyopagus -- which means they were connected from the chest all the way down to their shared pelvis. Conjoined twins occur when a single fertilized egg -- destined to become a pair of identical babies -- fails to completely split into two. Separation surgery is no longer the death sentence to one twin that it once was, but it's still a risky operation -- especially if important organs are shared.

But the hospital's surgical team managed to separate and save both infants during a 26-hour surgery in February, when they were just 10 months old. Now, the girls are both living at home.