Six weeks after undergoing the operation on February 20, twin sisters Panwad and Pantawan Tiyenjai are now healthy, said Clinical Professor Somchai Sriyoschati, the cardiovascular surgeon who led the heart surgery team.

The operation took more than 12 hours and required a total of 61 medical personnel including 14 anaesthetists, five cardiovascular surgeons, seven plastic surgeons and paediatric surgeons, and 30 nurses.

Because of their physical state from birth, Somchai said they would continue to have minor development problems, such as in eating, but these would be corrected in due course.

The only significant health problem for the two was that Panwad had a slight leak in her upper heart valve. This would be fixed later when she had grown a bit more, Somchai said.

Asst Prof Mongkol Laohapensang, who led the liver surgery team, said the livers of the two infants were in good shape and would grow to a normal state soon.

Before the operation, the doctors were uncertain whether the connected hearts of the twins could be separated safely because the upper right chamber of Pantawan's heart was joined to the upper left chamber of Panwad's, Mongkol said.

Blood also was flowing from Pantawan's heart to Panwad's through the connected channel, he said.

Because there was very little space between the hearts, it was difficult to assess whether the operation could be carried out. But after several examinations, doctors found separation was possible and that the twins could lead individual lives, Somchai said.

Among the medical techniques employed to ensure the two connected hearts could be separated safely were a heart balloon and magnetic resonance imaging (MRI), Mongkol said.

"I have to say that I was very nervous about not missing [the target] by a single millimetre while operating," said Somchai, referring to the most difficult part of separating the centimetre-long tube where the twins' hearts were connected.

"We did research on the Internet on published English literature going back more than 30 years but didn't see any reports of a successful operation of conjoined twins with these complicated conditions," said Prof Piyasakol Sakolsatayadorn, dean of Siriraj Hospital's Faculty of Medicine.

"And if there are no other successful cases reported in other languages, then this operation should be the first in the world," he said. "As far as I am concerned, the only previous success was a separation of connected twin hearts with no shared nerves, and it left only one alive."

"We feel dearly grateful to the doctors for this success," said Usa Tiyenjai, the twins' mother, who is from Samut Sakhon.

"It's been the longest moment of anxiety in my life. I was so glad and thankful to the doctors," said Thavorn Tiyenjai, the father.

The cost of the operation and care of the twins from birth to the day they were separated was estimated to be about Bt1.5 million.

Arthit Khwankhom

The Nation