Father: 'Future looks very bright' for twins

The twins' parents talked to reporters Wednesday after their daughters' separation.

LOS ANGELES, California (CNN) -- A day after doctors successfully separated conjoined twin girls, their father told reporters, "The future looks very bright."

Speaking through an interpreter at a news conference outside UCLA Medical Center in Los Angeles, Wenceslao Quiej Lopez said his 1-year-old daughters look very different now that they are no longer attached. He said he had trouble telling them apart because they still have large bandages covering their features.

"[I] was just very happy that the children were separated, [I] thanked God, and am just happy that they are separated," Quiej said through the interpreter.

Maria Teresa Quiej-Alvarez and sister Maria de Jesus were separated Monday in a series of operations that began Monday and lasted for almost 24 hours. They had been joined at the head for the first 377 days of their lives.

Twin facts Combined weight at birth: 4.4 pounds Birth date: July 25, 2001 Country of birth: Guatemala Number of doctors and nurses: More than 50 Surgery cost: $1 million to $1.5 million Hospital: Mattel Children's Hospital at UCLA Medical Center Operation time: 22 hours Donations: Send checks payable to the UCLA Foundation to: "Twins Care at UCLA" Fund UCLA Medical Sciences Development 10945 Le Conte Avenue, Suite 3132 Los Angeles, CA 90095  CNN NewsPass Video    •  Conjoined twins look to the future  RELATED   •  40-year-old conjoined twins oppose separation   •  Timeline: A historical look at conjoined twins   •  Gallery: Separating conjoined twins   •  Factfile: Conjoined twins   •  Illustrations: Separating twins

Queij said it had been very difficult to care for the twins when they were attached.

Dr. Andy Madikians, who is overseeing the girls care, said they are still in critical condition but their vital signs are pretty stable, and they are doing well considering they are recovering from major surgery.

"We have them heavily sedated and we're using some muscle relaxants," Madikians said, "so at this point, they haven't opened their eyes yet. They're still in critical condition, but everything seems to be going well. They're pretty stable."

'Everything moved very nicely'

He said doctors would begin slowly cutting back on the sedation and the paralytic agents over the next two days, allowing the girls -- still on a ventilator -- to breathe more independently.

"Determining whether there's any brain injury still at that point might be difficult to assess totally," he said, and will become clear only over a longer period of time.

He said that after the surgery and before the girls were given the muscle relaxants, they seemed to be moving normally for surgery-weary 1-year-olds.

"Both of them moved all their extremities -- their hands, their feet -- everything moved very nicely," Madikians said. "Both of them had a nice cough. They were strong enough to cough."

"The parents are doing really very well," Dr. Michael Karpf of the UCLA Medical Systems told CNN's Connie Chung Tonight. "This has been a very difficult ordeal for them -- they're so far away from home, so much is going on -- but they've been doing very well, very appreciative of everything we're trying to do."

Karpf said he "couldn't have asked for more from the parents."

The girls were born July 25, 2001, after their mother underwent eight days of labor near their home in rural Guatemala. Their mother is a homemaker, their father a farm worker.

A Spokane, Washington-based nonprofit organization called Healing the Children arranged for the girls and their parents to be flown to Los Angeles.

Operating room personnel donated their services for the 22-hour operation, but it still cost the hospital about $1.5 million. The hospital has established a fund to recover expenses.

Doctors say twins should lead normal lives

The two Marias are in recovery at Mattel Children's Hospital in Los Angeles.

In some respects, doctors have said, the girls were lucky because each had a separate, normal-sized brain with a membrane between them. That meant surgeons did not have to cut through any brain tissue.

The arteries that carry blood to the brains were also separate, doctors said, but their veins were crisscrossed and had to be rerouted.

Just hours after they were separated, Maria Teresa was rushed back into the operating room for another, almost five-hour operation because she developed a buildup of blood beneath the membrane surrounding the brain. Doctors said the subdural hematoma was not directly related to Monday's surgery.

Dr. Jorge Lazareff, director of pediatrics at UCLA, has said he hopes for a good "if not excellent" prognosis for the twins.

Earlier, he said Maria Teresa was holding up valiantly under the circumstances.

"We are very positive with the way she is responding," he said.

Lazeroff reiterated that he is quite confident that by age 5, both twins will be leading normal lives.

Doctors believe cases of conjoined twins are caused when the single egg that would normally divide into two to create identical twins does not wholly separate. As a result, some of the body parts are fused, according to experts.

In 40 percent of cases, conjoined twins are stillborn. Another 35 percent of them survive until their first birthday. In only about 2 percent of cases are the twins joined at the head. Because such cases are so rare, there are no statistics about success rates of surgery to divide them.