Following 27 hours of surgery, conjoined twins Jadon and Anias McDonald have been successfully separated, CNN reports.

The two brothers, originally from Coal City, Illinois, were born with a rare medical condition known as craniopagus in September 2015. They lived the first 13 months of their lives with the tops of their heads fused together before undergoing surgery at Montefiore Medical Center in New York City on October 13 and 14.

Led by Dr. James Goodrich, 40 doctors were able to disconnect the patients’ skull and brain tissue using advanced imaging technology. At one point during the operation, doctors encountered a 5-by-7-cm area of brain tissue “with no definite plane for dissection,” according to a Facebook post shared by the boys' mother, Nicole McDonald. She wrote, “Dr Goodrich had to make the call and the final cut based on his instinct.”

Craniopagus is exceedingly rare—occurring just once in every 2.5 million births—and the surgery needed to correct it is risky. A 2006 report co-authored by Goodrich [PDF] that looked at 41 craniopagus surgeries found a 77 percent success rate with multiple-stage operations and 37 percent success with those performed all at once.

The twins' separation surgery was their fourth procedure. Both boys experienced slight complications following their most recent surgery: Anias had seizures the next day, and Jadon still hasn’t moved his left side. While Jadon’s issue is more worrisome, his father Christian told CNN Goodrich told him “that's not out of the ordinary.” It took about a month for Jadon and Anias to fully recover from their previous operation, and the family is looking at a similar timeline this time around.

[h/t CNN]
 
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