Doctors completed reconstructive surgery on one of two formerly conjoined twins Tuesday after a 16-hour operation separated the girls born fused at the midsection.

Four-year-old Maliyah Herrin was recovering in a pediatric intensive care unit while plastic surgeons continued to build an abdominal wall for her sister, Kendra.

The twins had shared a liver, a kidney, a pelvis, one set of legs and part of their intestines.

Surgeons at Primary Children's Medical Center gave each girl one leg, split their liver and intestines and reconstructed their bladders and their pelvic rings.

Kendra kept their one functioning kidney, while Maliyah was prepped for kidney dialysis and a transplant in three to six months.

The Herrins' separation is believed to be the first performed on conjoined twins with a shared kidney, said the hospital's chief of pediatric surgery, Dr. Rebecka Meyers.

Meyers said the surgery, while complicated, had not presented any major surprises for the team of six surgeons, two anesthesiologists, two urologists, one radiologist and more than 25 nurses and medical technicians.

But the days ahead will still be tough, she said.

"We have big concerns with both girls," said Meyers. "Maliyah's big concern is her kidney function and her dialysis ... And Kendra's big concern is going to be the coverage of her abdomen."

Surgeons said Kendra has less muscle and tissue for use in closing her abdomen. They planned to use synthetic skin to help solve the problem.

Meyers said Maliyah did not require immediate placement on dialysis, but she expects that may happen within a few days. When the girl is strong enough, she'll get a kidney from her mother, Erin Herrin.

"For kidney transplant, my time frame is really dictated more by Maliyah than by me, because there are just benchmarks she has to meet," Meyers said.

The twins are expected to remain in intensive care for about a week and recover in the hospital for at least a month before doctors can consider sending them home, Meyers said.

Conjoined twins occur about once in every 50,000 to 100,000 births. Only about 20 percent survive to become viable candidates for separation.

In most instances, conjoined twins undergo separation surgery between ages 6 and 12 months, but the girls' shared kidney forced a delay.

Erin Herrin, 25, broke into tears and fell into the arms of her 26-year-old husband, Jake Herrin, when the couple was told the surgery had been successful. Relatives applauded.

The couple said they were nervous about seeing the girls separate for the first time.

"I don't know that it's set in yet," Jake Herrin said. "We're not going to feel totally comfortable until they're out of the OR and everything's stable."

"And we can hold them," his wife added.

The couple, who also have a 6-year-old daughter and twin 14-month-old boys, said they were eager to tell the girls how brave they had been and how proud they've made the family.

Jake Herrin even cracked a few surgery jokes.

"Most people say, 'You made it through in one piece," he said. "We can say, "You guys made it through in two."'