A risky operation to remove a second head from a baby with an extremely rare birth defect has resulted in her death. Baby Rebeca Martinez bled to death following surgery to prise away the “parasitic head” which, if left, would have killed her.
The operation was the first of its kind to be attempted and took 12 hours to complete. Initially, it appeared to be a success. Benjamin Rivera, one of the 18-strong team of doctors, said the procedure to cut off the second head while separating and clipping intertwining blood vessels “went very well”.
However, Rebeca suffered severe haemorrhaging. Three hours after the operation, at 0130 EST on Saturday, an attempt by doctors to stop the bleeding failed. She died about 0800 EST at CURE International’s Center for Orthopaedic Specialties in Santo Domingo, Dominican Republic.
Rebeca was born in mid-December 2003 with the head of an undeveloped twin fused to the top of her skull. The extra head had a partially formed brain, ears, eyes and lips and shared a vital blood supply with her brain.
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The condition, known as Cranio Pagus Parasiticus, is extremely rare and eight cases have ever been documented. Of these, only one was not stillborn. This made Rebeca’s operation unique, as she was the only such baby to live long enough for surgery to be attempted.
The operation would have been extremely risky because of the blood connections between the brains, says Lewis Spitz, a leading expert on separating conjoined twins at Great Ormond Street Hospital, London, UK. “They obviously did their best, and I’m sorry they didn’t succeed,” he told New Scientist.
He adds that provided all precautions had been taken, it may not have been advisable for the team to wait any longer. “The younger a baby is – the more pliable the tissues are, but then there’s the risk of bleeding,” he says.
Vital artery
The rare condition begins when identical twins fail to separate in the womb. In some cases, each twin still goes on to develop, resulting in babies conjoined at the head. This occurs about once in every two million live births. But in Rebeca’s case, one of the twins had failed to develop normally and formed a smaller dependent attachment.
The international team of doctors knew the operation would carry risks of heavy blood loss as the brains shared a vital artery – a branch of the carotid.
However, they felt surgery was necessary as Rebeca’s brain would not be able to develop because of the second head draining off its blood supply. “The head on top is growing faster than the lower one,” said Jorge Lazareff, who led the team, before the operation. “If we don’t operate, the child would barely be able to lift her head at three months old.”
Lazareff, of the University of California’s Mattel Children’s Hospital, successfully separated Guatemalan twins joined at the head in 2002.
Planned operations to separate conjoined twins have reasonable success rates. Spitz says nine planned operations have taken place at Great Ormond Street Hospital since 1985, with 15 of the 18 babies surviving – 83 per cent. In contrast, just 29 per cent of the seven emergency operations to separate conjoined twins at the children’s hospital succeeded.
Undeveloped parasitic twins are “not uncommon” Spitz points out. And operating on these are often straightforward, he says. For example, his team has operated on babies with four legs, babies who have parts of limbs attached to their trunks or backs, and even a parasitic foetus within the abdomen of its twin. “What you have to do is remove the abnormal part – there’s no question of saving another individual life,” he explains. And tissue can be used from the discarded part to close up the wound.
