(AP) -Mayo Clinic surgeons successfully separated 5-month-old conjoined twins from Bismarck, N.D., and went to work on the challenging job of reconstructing their chest walls, the clinic said. Abygail and Madysen Fitterer were brought into the operating room just before 7 a.m. and were put to sleep for the surgery. Surgeons made the first incision around 9:50 a.m., and went to work separating their shared front chest wall, the clinic said.
The girls were placed on separate operating tables at 12:27 p.m., and the surgical teams then began reconstructing their chest walls.
The surgical team was led by Dr. Christopher Moir, who also led the teams that separated conjoined twin girls from Fargo, N.D., in May and twin boys from Mankato in November.
"Dr. Moir and the team believe there's a high likelihood of success - that's why they're going forward with it - but in any operation there's certainly risk," Mayo spokesman Lee Aase said on Tuesday.
The Fitterer twins have been at Mayo since doctors implanted tissue expanders in October to slowly stretch the girls' skin enough to close their incisions from the separation surgery.
Though Aase said the main challenge would be separating and reconstructing their chest walls, their livers were also joined and they shared some intestine.
The girls are the daughters of Stacy and Suzy Fitterer, who posted a tribute to Abygail, Madysen and their son, Nicholas, on Thursday on the family's Web page at www.caringbridge.org.
"Dear Nicky, Abby and Maddy: Thank you so much for the pure joy and pleasure you have given us." they wrote. "You have taught us the importance of living, truly living each day and loving the 'big' days and the 'little' days."
The surgical team planned to hold a news conference Wednesday evening following the operation, which Aase said would be Mayo's fifth separation of conjoined twins. Besides the two sets last year, Mayo did two other separations around 10 years ago, he said.
According to Mayo experts, conjoined twins may develop in as many as one in 50,000 pregnancies, but they account for only one in about 250,000 live births.