Tennessee surgeons have successfully separated conjoined twins, Jacob and Joshua Spates, who were connected at the lower spine and pelvis.
The twins' mother, Adrienne Spates, told TODAY that the twins are doing well after the 13-hour Aug. 29 surgery: Jacob is in the intensive care unit and is scheduled for some additional surgeries, while Joshua is now in the recovery floor of the hospital and will soon come home.
"Joshua's doing great, and hopefully he'll be up and going and have a pretty normal lifespan," Dr. Max Langham, one of the twins' surgeons at Le Bonheur Children's Hospital, told TODAY. Jacob, who has heart problems, still has to undergo treatments and surgeries, but "our cardiology team has very high hopes his treatment … will be successful," Langham said.
The twins were born at 34 weeks old last January. They were conjoined from the back at the pelvis and the lower section of the gastrointestinal tract, TODAY reported. However, they had their own hearts, heads, chests, legs, arms and other important internal organs, so they are very much "two different boys," Spates said.
The separation of the twins was necessary in order for doctors to repair Jacob's heart condition, Langham told TODAY.
"If they had not been separated, sometime in the next year or two, they probably would have passed," Langham said. He added that the hardest part of the surgery was the neurosurgical separation of the twins' pelvis and lower spinal cord.
There were more than 100 surgeons involved in the medical team to separate the twins. The surgeons practiced for the surgery on sewn-together Cabbage Patch dolls, to make sure they didn't tangle things up during the actual surgery, according to Prime News.
The twins are one of two dozen conjoined twins who have been successfully separated in the world, ABC News reported. Only about 15 percent of conjoined twins are connected the same way the Spates were, at the pelvis -- called pygopagus twins.
Conjoined twins are extremely rare, accounting for just 1 percent of monozygotic twins, according to Medscape. Monozygotic twins is a type of twin that only makes up a third of twin births; twin births are already rare, and happen in just 1 of every 87 births. Conjoined twins make up one of every 33,000 to 165,000 births in the United States, and one of every 200,000 live births, Medscape reported.
Most conjoined twins are fused at the abdomen or the thorax (between the head and the abdomen), Medscape reported. Conjoined twins are either "equal conjoined" twins -- meaning they're both well developed separately -- or "unequal conjoined" twins -- meaning one of the twins is incomplete and is attached to the more fully developed twin.
Live-born conjoined twins are more commonly girls, while stillborn conjoined twins are more commonly boys, according to Medscape. It's common for conjoined twins to be born stillborn, with stillborn births occurring 40 to 60 percent of the time in cases of conjoined twins.
More:Healthy Living Health News Conjoined Twins Pelvis Healthy-living-health-news Conjoined Twins Today Show Conjoined Twins
HuffPost Lifestyle is a daily newsletter that will make you happier and healthier — one email at a time. Learn more