SAN DIEGO — Doctors announced Thursday that they will perform surgery to separate the Siamese twins born to an impoverished Tijuana couple, although one of the twins appears to have only a marginal chance of survival.
A team of five surgeons, backed by pediatricians and nurses and other health professionals, will assemble Saturday at Childrens Hospital to separate Sarah and Sarahi Morales, who are joined at the chest, abdomen and liver.
Sarah, the stronger twin, has a small hole in her heart, but doctors say it can be repaired.
"I would be surprised if baby A [Sarah] does not survive," said Dr. John J. Lamberti, chief of cardiovascular surgery.
Sarahi, however, has a severely deficient heart with one-third of a normal heart rate. Because the two hearts share some arteries, Sarah, in effect, has been keeping Sarahi alive, doctors said.
Sarahi will be put on a cardiac pacemaker as soon as she is separated from her sister and will receive "aggressive treatment," Lamberti said.
The decision to attempt the surgery despite the risks to one of the twins was made by parents Maria Luisa Espinoza and Miguel Angel Morales. Morales, 30, is a mechanic who makes $50 a week.
The first task facing surgeons will be to separate the two livers. In most surgeries to separate conjoined twins, one or both die. But in this case doctors have been optimistic because the two have separate hearts.
The twins were born Jan. 12 in a small clinic near the family's home in Tijuana and brought to Childrens Hospital a week later when the family could not find a Tijuana hospital able to help them.
Among conjoined twins, attachment at the chest is the most common condition (73%), followed by the buttocks (19%), hip (6%) and head (2%). Estimates are that 60% of conjoined twins are stillborn and most live only a few days. Because of their rarity, there is little information in medical textbooks on how to separate conjoined twins.
"No two sets of conjoined twins are the same," said Dr. Michael Nihill, a cardiologist at Texas Childrens Hospital in Houston. "There are any number of heart defects that can be present. It's important that the doctors know as much as possible about each twin before they start surgery. They can't just go exploring."
Nihill was part of the surgical team that successfully separated twin girls joined at the chest during a 14-hour operation in 1992. Both survived.
Doctors at San Diego's Childrens Hospital initially said a review of medical journals could find only one case in which twins joined at the chest had been separated with both surviving. But now it appears that there are at least two such cases. Both cases came from Texas Childrens Hospital, which serves as a teaching hospital for Baylor College of Medicine.
In the 1992 case, doctors waited until the twins were 13 months old and much stronger than newborns before attempting surgery. Even after being separated, the twins suffered postoperative complications and required extensive hospitalization and treatment.
Doctors at Childrens Hospital in San Diego, however, said the heart deficiencies of Sarah and Sarahi Morales required that surgery be done within a few days.