WASHINGTON, D.C. ? Separated conjoined twin boys were doing well Thursday but still face a long recovery, and doctors questioned whether one will be able to walk.

“We’ve climbed Mount Everest,” said the chief surgeon who separated the twins, Dr. Robert Keating.

“We’re at the top. It’s a great view, it’s very exhilarating and everyone’s very excited, but we have to come down. And we have many, many roads ahead of us – many medical issues to be dealt with.”

Chief among them, Keating said, was spina bifida.

“We’re not out of the woods,” he said at a news conference at Children’s National Medical Center.

Mateo Asher Shaw and McHale Twain Shaw, 4-month-old sons of Angie Benzschawel, 25, and Ryan Shaw, 28, of Sheboygan, Wis., were in critical but stable condition a day after spending about 19 hours in surgery.

The twins were born May 10 joined at the lower back with conjoined spinal cords.

“Everything went according to plan,” Keating said. “The biggest surprise was there were no surprises.”