Doug Mills, Associated Press

Sen. Edward M. Kennedy underwent surgery Friday to repair a partially blocked artery in his neck, which was discovered during an examination of a decades-old back injury.

Kennedy, 75, underwent the hourlong procedure on his left carotid artery — a major supplier of blood to the neck and head — at Massachusetts General Hospital in Boston, his office announced.

The operation, performed by Dr. Richard Cambria, the hospital's chief of vascular surgery, was completed without complications, and the Massachusetts Democrat was expected to be released in several days, his Washington office said in a statement.