Surgeons will spend about nine hours today separating two-year-old conjoined twins at Stanford.

The first hour is preparation. Then the doctors will sever Angelica and Angelina's shared sternum, but luckily their ribs are not attached. Their hearts are also separate which makes the surgery less complicated than one performed (successfully) by some of the same surgeons also at Stanford in 2007. The girls also share a liver, and doctors say dividing will be the most complicated part of the day because of the risk of hitting veins and arteries. Angelica and Angelina also share a diaphragm that must be divided.

The last hour or so of the procedure will be spent reconstructing the girls' chests and abdominal walls by implanting a thick plate into each girl, which their bodies will absorb as they heal. They'll recover in intensive care for about five days, and will hopefully go home a week after that.

Watching them toddle around in the video above is amazing. They walk with the typical unsteady gait of a two-year-old, but as a unit on four legs. I couldn't help but worry that the place where they're attached might hurt as they run from one side of the room to the other, bending over and standing up again on a quest for stickers. But it's clear they're not in pain. They've never known anything but being joined to their sister at the chest. Almost every news story about them out today mentions that when one coughs, the other pats her pack gently.

They seem happy enough, why not just let them be? After all, the surgery is risky with the complicated liver-separation procedure as well as tricky anesthesia. But if they stayed joined, their spines would become even more curved than they already are, and they would develop muscle problems, not to mention the social the issues that come with being attached. They're also an increasing challenge for their mother to dress: she currently cuts their clothes down the middle and joins them with velcro. Clever!

Conjoined twins are rare: they happen in 1 in up to 100,000 births. Surgeries to separate them are performed approximately six times per year—the surgeon separating Angelica and Angelina has done it five times before. And that's about as experienced as a conjoined twins separator gets. [San Jose Mercury News]


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