After a successful operation, a pair of 10-month-old conjoined twins are now separated. The girls, Erin and Abby, were connected at the the top of their heads, a rare condition called craniopagus. But, they are now able to live separate lives thanks to a multidisciplinary team at the Children’s Hospital of Pennsylvania (CHOP).

“Separating conjoined twins is a very complex surgery followed by a long and complicated recovery, but we are very hopeful for a positive outcome,” Dr. Jesse Taylor, a plastic surgeon at CHOP, said in a statement. “Erin and Abby are now recovering in our Pediatric Intensive Care Unit under close monitoring by our expert teams.”

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The 11-hour procedure involved a team of 30 including physicians, nurses, anesthesiologists, and other specialists. Although CHOP surgeons have previously completed operations on conjoined twins, this is the first they've done on a pair with craniopagus.

Typically, conjoined twins are born connected at the upper portion of the torso which is known as thoracopagus twins, according to the University of Maryland Medical Center. This type of twins makes up about 40 percent of all conjoined twins cases. Another common classification, called omphalopagus, involves being connected from the breastbone to the waist. But Abby and Erin’s type, craniopagus, is the most rare of all - making up only 2 percent of all cases.

“During the separation surgery, our team first meticulously separated the infants’ shared blood vessels and dura, the tough protective membrane surrounding both brains, then moved on to separate the sagittal sinus, the most difficult portion of the operation,” Dr. Gregory Heuer, a neurosurgeon at CHOP, said. “Finally, we divided our team into two halves, one for each of the girls, and finished the reconstruction portion of the surgery.”

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The girls currently remain in the hospital where they will stay for months of recovery. Although the most lengthy and complex portion of their surgery is complete, they will most likely need more procedures in the future. But, in the meantime, their parents are anxiously awaiting the moment they can bring their children home.

“When we go home, it’s going to be a big party,” Erin and Abby’s mother, Heather, said in a statement. “Welcome home, baby shower, first birthday.”

Surgically separating conjoined twins is a delicate and risky procedure. Success rates have improved over the years, but there is still a high risk of death. Since 1950, at least one twin has successfully survived separation surgery about 75 percent of the time, according to the University of Maryland Medical Center.

See also: Surgeons Use CT Imaging And 3D Printing To Successfully Separate Conjoined Twins

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