Doctors in a Houston hospital on Monday have successfully separated a pair of conjoined 10-month-old girls and are optimistic that the twins will survive the surgical operation.

According to Todd Ackerman of the Houston Chronicle, more than 30 surgeons worked from Tuesday morning to Wednesday morning at Texas Children's Hospital to separate Knatalye Hope and Adeline Faith Mata, who were both joined from the chest to the lower trunk. The procedure was planned way before the girls were born.

"The surgery was not without its challenges, with the girls sharing several organ systems, but we're very pleased with how they're doing," lead surgeon Dr. Darrell Cass said. "We're very optimistic they can both have a really great outcome."

Cass added that the girls were in stable but still critical condition after the surgery, noting that the successful surgery "literally brought tears to my eyes." The hospital plans to take them off ventilators within a week, but the twins will stay in the intensive care unit for a couple of months for their recovery, according to Ackerman.

To be closer to their children, Ackerman reported that Elysee and John Mata, the girls' parents, moved to Houston from Lubbock, Texas. The parents released a statement thanking the surgeons and everyone else for allowing their daughters to have "the incredible chance to live separate lives."

"We know how much planning and time went into this surgery and we are so blessed to be at a place like Texas Children's, where we have access to the surgeons and caretakers that made this dream a reality," Eylsse Mata said.

The twins were officially separated 18 hours into the surgery, according to Ackerman. Before the surgery was done in real time, doctors prepared for the procedure by conducting a five-hour simulation and built "3D models of the twins' skeletons, blood vessels and shared organs."

"The team included eight nurses, six anesthesiologists and 12 surgeons, subspecialists in pediatric, cardiovascular, urology, liver transplant, orthopedic, pediatric gynecology and plastic surgery," Ackerman wrote.

Ackerman reported that the hospital made the announcement on Sunday night, adding that it was first separation surgery to be performed in Houston in nearly 20 years.

"A team at Memorial Hermann separated conjoined twins in 1997 and a team at Texas Children's separated twins in 1992," Ackerman wrote. "Neither case was as complex as last week's, both successful. All four children are still alive."

The Houston Chronicle reported that giving birth to conjoined twins is a rare condition, which is estimated to occur once in every 200,000 live births. The condition happens when the egg fails to divide completely soon after fertilization, and the developing embryo stops splitting into identical twins before finishing the process.