Former President Clinton (search) was in good spirits and looking forward to getting on his feet after surgery to remove scar tissue and fluid from his left lung, his wife said.

Sen. Hillary Rodham Clinton (search) and their daughter, Chelsea, were at the hospital Thursday as doctors cleaned up complications from Clinton's heart bypass (search) operation of six months ago.

Hospital officials predicted "even better than a full recovery" for the former president following the four-hour operation and predicted Clinton would be walking within 24 hours.

"Chelsea and I have been with him, and he's in good spirits and looking forward to getting up and walking around," Hillary Clinton said in a statement.

Clinton was expected to spend three to 10 days in the hospital, said Dr. Herbert Pardes, president of New York-Presbyterian Hospital/Columbia University Medical Center.

Sen. Clinton said that although this was not considered a life-threatening procedure, "that didn't stop Chelsea and me from worrying together and praying together."

In a rare complication from his bypass surgery in September, scar tissue had developed because of fluid buildup and inflammation, causing compression and the collapse of the lower lobe of Clinton's left lung.

Surgeons removed a thick rind of scar tissue, in some places up to 8 millimeters (0.3 inches) thick, which made it impossible to use a minimally invasive videoscopy. Instead, surgeons performed more traditional surgery.

"It was like peeling an orange," said Dr. Joshua Sonett, one of the surgeons, about removing the tissue.

By the end of the operation, Clinton's lung "was very healthy and looked excellent," he said. "We expect even better than a full recovery."

The operation was done at the same facility where Clinton underwent open-heart surgery. Doctors described it as a low-risk procedure, and Clinton himself called it routine.

Still, such problems crop up in only a faction of 1 percent of bypass cases; doctors said the combination of fluid and scar tissue had decreased Clinton's left lung capacity by 25 percent. The former president first noticed the problem when he suffered shortness of breath during his daily 4-mile walk.

The surgery began about two hours after Clinton arrived in an SUV at the Manhattan hospital on a brisk winter morning. The Secret Service, police and hospital security staff conducted a sweep of the walkways and corridors as Clinton was whisked inside through a side entrance before the operation.

The former president had been in Florida on Wednesday at a charity golf tournament to benefit tsunami victims. He appeared relaxed, cracking jokes about his golf game and saying he wasn't worried about the surgery.