Two conjoined sisters were living separate lives last night for the first time since they were born 11 months ago thanks to 13 hours of highly complicated surgery at Fudan University's Children's Hospital.

"The twins' deformity was very rare, and theirs was the first separation surgery of its kind in the world," said Gui Yonghao, president of the Shanghai hospital. "It would have been a miracle for one child to survive and a challenge to the limits of medicine for both to survive. We made it."

Doctors and nurses escort 11-monthold Chen Jingni to an intensive care unit yesterday after a 13-hour procedure separated her from her twin sister, Hu Jingxuan, at Fudan University's Children's Hospital. [Shanghai Daily]

The infants are far from out of the woods yet. Both have congenital heart conditions and will require additional followup surgeries.

Chen Jingni, the stronger of the two, was taken to the hospital's intensive care unit after the separation procedure. Her sister, Hu Jingxuan, remained in the operating room last night because of her more serious heart condition. She won't be moved the three floors to the ICU until her condition stabilizes.

"I'm extremely happy that the surgery was successful; I've dreamed of holding them separately for a long time," said mother Chen Yanfen, who, like her husband, is a farmer from Taizhou in Zhejiang Province.

In deciding to schedule the surgery for yesterday, doctors had to balance the risk of the traumatic procedure against the harm that could come from delay, as the girls' hearts were weakening.

"We discussed medical ethics before the surgery, assessing the condition of the patients, the operation's risk and the family's opinion," said Xu Hong, a hospital official. "Since the twins were in critical condition and their heart function was fading, we decided to conduct the surgery after receiving the family's agreement."

To ensure the success of the operation, the hospital halted all elective procedures yesterday, putting its entire staff of experts on standby.

At 8 a.m., a team of 27 doctors, seven anesthesiologists and eight nurses began the delicate procedure to decouple the girls, joined from the upper chest to the lower pelvis.

Surgeons had to separate the infants at the bladder, uterus, pelvis, intestines, liver and the sac that covers the heart.

The girls were finally freed from each other at 5:20pm, and surgeons began the task of repairing their tissues.

"Though they are now in stable condition, the twins still face potentially fatal challenges such as organ failure, infection, blood disorders and nutritional problems," Gui said.

Doctors estimated the cost of the surgery at 160,000 yuan (US$20,016). The Taizhou Commercial Association has agreed to donate 260,000 yuan for medical expenses and sent in 160,000 yuan yesterday.