The first operation to remove an undeveloped second head from a baby born with an extremely rare birth defect is to go ahead on Friday.
Baby Rebeca Martinez was born in the Dominican Republic in mid-December 2003 with the head of an undeveloped twin fused to the top of her skull. The extra head has a partially formed brain, ears, eyes and lips and shares a vital blood supply with the baby鈥檚 brain.
Although, Rebeca is otherwise a healthy baby, her brain will not be able to develop normally with the parasitic brain in place.
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鈥淭his parasitic formation is fed by and drains off the blood supply system of baby Rebeca鈥檚 head,鈥� says Santiago Hazim, medical director of CURE International鈥檚 Center for Orthopedic Specialties in Santo Domingo. An international team of 18 will work at the hospital to prise the brains apart.
鈥淭his is medical history,鈥� said Benjamin Rivera, one of the team, speaking to USA Today. The condition, known formally as Cranio Pagus Parasiticus, is extremely rare, with only seven other cases ever reported. Only one of these cases was not stillborn, and that was 200 years ago, says Rivera.
Failed separation
The condition begins when identical twins fail to separate in the womb. Sometimes, each twin still goes on to develop, resulting in babies conjoined at the head. This occurs about once in every two million live births. However, in the latest case, one of the twins failed to develop normally and now forms a smaller dependent attachment.
The risky operation is expected to take 14 to 16 hours. Jorge Lazareff, who will lead the team along with Rivera, believes the baby鈥檚 chances of survival are good but will not speculate on the odds. Lazareff, a neurosurgeon at the University of California at Los Angeles, successfully separated Guatemalan twins joined at the head in 2002.
The team will cut off the undeveloped head, clip the blood vessels and seal the skull using a bone graft from another part of Rebeca鈥檚 body.
A major risk of the operation is bleeding within the skull. 鈥淚f we cut into an artery or vein, we鈥檙e going to have a hard time saving her life,鈥� Hazim says.
One major artery, a branch of the carotid, is known to supply both brains, but until surgeons open the baby鈥檚 skull they cannot be certain about other connections between the brains. However, if the delicate surgery is successful, Rebeca is expected to develop normally.