State College Mayor Bill Welch was listed in serious condition yesterday after he underwent a planned surgery at Hershey Medical Center Friday to repair an abdominal aortic aneurysm, a potentially life-threatening ailment.

A Hershy spokeswoman said Welch's 'serious' condition is stable but progressing. He is still being monitored closely, she added. Friends and neighbors of the Welch family said the surgery was preformed without complications. "He went through it extremely well," said Welch's neighbor, Donna Queeney. "He was in good health going into it."

Welch is expected to remain in the hospital for a least a week, then return home for a six-week recovery period, said Borough Council president Richard McCarl.

Welch is expected to return to his full duties at the end of March. During his absence, the council will conduct its regular voting meetings and work sessions without interruption, McCarl said.

The only difference will be that the borough president will wield the gavel and run the meetings, rather than the mayor, he said.

"I'm always happy to have him there," he said. "But when he's not, we'll try to keep going without him."

Many of the formalities Welch normally performs -- such as ribbon-cutting ceremonies -- will be put on hold, McCarl said. The borough manager or other officials will perform events that cannot be postponed, he said.

"We'll try to cover for anything he would normally do," McCarl said.

An aneurysm is a weakening in the muscular walls of a section of artery which results in an enlargement or sagging of the damaged section.

If the weakened section ruptures, blood pools out into the body, resulting in hypotension, coma and possibly death. To correct the weakness, surgeons remove the section or the artery and replace it with a piece of flexible tubing. Everybody reacts differently to an operation, Queeney said. The mayor's positive attitude has a great deal to do with his success both as a person, and during surgery. He always assumes everything will go for the best, she said.

"We're very encouraged by his progress," Queeney said.

This has not been the first time the mayor has gone under the knife while in office. He underwent kidney transplant surgery in 1994 without complication.

"In the past he has certainly shown his resilience," Queeney said. "He will be back at the helm in no time."