A baby girl born with one of the world's rarest birth defects has died of complications following an operation in which a second live head was removed.
The landmark surgery took place yesterday at the CURE International Centre for Orthopaedic Specialities in Santo Domingo and lasted for 11 hours, with a team of 18 surgeons and nurses taking shifts.
Rebeca Martinez was born in mid-December at a hospital in the Dominican capital with the head of an undeveloped twin attached to the top of her skull, facing upward. The infant was otherwise healthy but her brain could not develop normally unless the undeveloped head was removed.
Doctors said the baby's blood refused to clot which lead to her death this afternoon.
The operation was led by Dr. Jorge Lazareff, director of paediatric neurosurgery at UCLA's Mattel Children's Hospital, and Dominican surgeons Hazim and Dr. Benjamin Rivera. Lazareff led the surgical team that successfully separated Guatemalan twin girls conjoined at the head last year.
The baby girl's condition, cranio pagus parasiticus, is so rare that there have only been eight documented cases in the world, and no known cases where surgery had been attempted to correct it, Hazim said in a earlier interview.
Conjoined twins form when an embryo begins to split into identical twins and then stops, leaving them fused. Twins conjoined at the head account for about one of every 2.5 million births and about 2 percent of all conjoined births.
Rarer "parasitic" twins occur when one conjoined twin stops developing in the womb, leaving a smaller, incomplete twin that is dependent on the other. They can form as an extra limb, torso or head, or as a complete second body, lacking vital organs.
In Rebeca's case, there was a gap in her skull where the heads were joined, and the blood vessels were intertwined. The vestigial head was enlarged and fringed with dark hair like Rebeca's but had a poorly developed brain and only rudimentary facial features.