"The head on top is growing faster than the lower one," said Dr. Jorge Lazareff, director of pediatric neurosurgery at the University of California at Los Angeles' Mattel Children's Hospital. "If we don't operate, the child would barely be able to lift her head at 3 months old."

Lazareff said the pressure from the second head, attached on top of the first and facing up, would prevent Rebeca's brain from developing.

The operation's start was delayed for about four hours due to complications in administering anesthesia.

"The girl is stable. So far all her vital signs are fine," said Dr. Santiago Hazim, medical director at the Center for Orthopedic Specialties in Santo Domingo, where the surgery was being performed.

CURE International, a Lemoyne, Pennsylvania-based charity that gives medical care to disabled children in developing countries, is paying for the surgery, estimated at $100,000. The agency funds the Center for Orthopedic Specialties.

The operation is risky because the two heads share arteries.

"When the doctors come out and tell us it's all OK we'll be filled with happiness," father Franklin Martinez, 29, told The Associated Press Thursday.

Lazareff was to lead the operation along with Dr. Benjamin Rivera, a neurosurgeon at the Medical Center of Santo Domingo and the Center for Orthopedic Specialties. Lazareff led a team that successfully separated conjoined Guatemalan twin girls in 2002.

Doctors say if the surgery goes well she won't need physical therapy and will develop as a normal child.

Twins are born conjoined at the head when an embryo splits to make identical twins and then stops growing, leaving them fused. Such twins are rare, accounting for one of every 2.5 million births.

Parasitic twins like Rebeca are even more rare. They occur when one stops developing, leaving a smaller, partially formed twin dependent on the other.

Rebeca is the eighth documented case in the world of craniopagus parasiticus, Hazim said.

All the other documented infants died before birth, making it the first known surgery of its kind, according to Lazareff and the other doctors.

Martinez and his 26-year-old wife, Maria Gisela Hiciano, say doctors told them Rebeca would be born with a tumor on her head but none of the prenatal tests showed a second head developing.

Although the second head is only partially developed, its mouth moves when Rebeca is being breast-fed. Tests indicate there is some activity in her second brain. Dr. Lazareff said the pressure from the second head, attached on top of the first and facing up, would prevent Rebeca's brain from developing.

Halfway Through Surgery

February 6, 2004, 9pm

A team of surgeons began a rare and risky operation Friday to remove the second head of a Dominican baby — a partially formed twin that threatens the girl's development.

The parents of 7-week-old Rebeca Martinez followed her to the door of the operating room and said a prayer over their baby, holding hands and gently caressing their daughter's head.

"Be strong, Rebeca. May God be with you," 26-year-old Maria Gisela Hiciano, said as she reached for her baby through the bars of the crib.

Led by a Los Angeles-based neurosurgeon, the medical team planned to spend about 13 hours removing Rebeca's second head, which has a partially formed brain, ears, eyes and lips.

The surgery is complicated because the two heads share arteries. Although only partially developed, the mouth on her second head moves when Rebeca is being breast-fed. Tests indicate some activity in her second brain.

Eighteen surgeons, nurses and doctors were to take several rotations to cut off the undeveloped tissue, clip the veins and arteries, and close the skull using a bone graft from another part of Rebeca's body.

By Friday evening, the operation was 90 percent complete, doctors said.
"They have taken out the extra brain and they're closing the cranium," said Dr. Santiago Hazim, medical director of Santo Domingo's Center for Orthopedic Specialties, where the surgery was being performed. "The risks have dropped significantly, but we still can't celebrate."

"We've taken off half the parasitic head, and we haven't had any hemorrhaging," said Dr. Santiago Hazim, medical director of Santo Domingo's Center for Orthopedic Specialties, where the surgery was being performed.

The operation was critical because the head on top was growing faster than the lower one, said Dr. Jorge Lazareff, the lead brain surgeon and director of pediatric neurosurgery at the University of California at Los Angeles' Mattel Children's Hospital.

Without an operation, he said, "the child would barely be able to lift her head at 3 months old."

Lazareff said the pressure from the second head, attached on top of the first and facing up, would prevent Rebeca's brain from developing.

CURE International, a Lemoyne, Pa.-based charity that funds the orthopedic center and gives medical care to disabled children in developing countries, is paying an estimated $100,000 for the surgery.

The operation had been delayed for about four hours while doctors carefully administered anesthesia.

Rebeca's mother and father Franklin Martinez, 29, waited in a separate room, watching baseball on television and receiving visitors who brought flowers and stuffed animals. Psychologists also visited them.

"When she was born everyone said, 'Wow, two heads,' but to us she was just our baby Rebeca," Martinez told The Associated Press.

Lazareff, who led a team that successfully separated conjoined Guatemalan twin girls in 2002, was leading the operation along with Dr. Benjamin Rivera, a neurosurgeon at the Medical Center of Santo Domingo and the orthopedic center.

Doctors say if the surgery goes well Rebeca won't need physical therapy and will develop as a normal child.

Rebeca was born on Dec. 17 with the undeveloped head of her twin, a condition known as craniopagus parasiticus.

Twins born conjoined at the head are extremely rare, accounting for one of every 2.5 million births. Parasitic twins like Rebeca are even rarer.

Rebeca is the eighth documented case in the world of craniopagus parasiticus, Hazim said.

All the other documented infants died before birth, making it the first known surgery of its kind, according to Lazareff and the other doctors.

Martinez, a tailor, and his wife, who is a supermarket cashier, together make about $200 a month and have two other children, aged 4 and 1.

They say doctors told them Rebeca would be born with a tumor on her head but that none of the prenatal tests showed a second head.

Lazareff has refused to make a prognosis but said earlier this week that Rebeca's chances of survival are good.

Infant Born With One of the World's Rarest Birth Defects

Conjoined twin, one-month-old Rebeca Martinez, lies in a hospital crib January 21, 2004. Rebeca Martinez was born in mid-December at a hospital in Santo Domingo with the head of an undeveloped twin attached to the top of her skull, facing upward. The infant is otherwise healthy but her brain cannot develop normally unless the undeveloped head is removed, said Dr. Santiago Hazim, medical director at the CURE International Center for Orthopedic Specialties, where the surgery is set for February 6, 2004 in the Dominican Republic. The baby girl was born with one of the world's rarest birth defects, caused when a conjoined twin fails to develop in the womb.

Rebeca Dies After Second Head Is Removed

07 February 2004, 9:55 am

SANTO DOMINGO, Dominican Republic - An infant girl died Saturday after surgery to remove a second head, her mother said.

A medical team completed the operation Friday evening but said 8-week-old Rebeca Martinez had been susceptible to infection or hemorrhaging. The baby died 12 hours after the surgery, believed to be the first of its kind.

The second head, which doctors said threatened the girl's development, grew from the top of her skull and had its own partly developed brain, ears, eyes and lips.

During the surgery, 18 surgeons, nurses and doctors had taken several rotations to cut off the undeveloped tissue, clip the veins and arteries, and close the skull using a bone and skin graft from the second head.