The 74-year-old was under general anesthesia for the operation in Milan, news agencies reported.
Berlusconi "underwent a maxillofacial operation with bone transplant and implant," his doctor, Alberto Zangrillo, said in a statement released by the prime minister's office. He was in good condition, his doctor said, and was recovering at his villa outside Milan, Agence France-Presse reported. Berlusconi could be back to work by Thursday, when a key Cabinet meeting is scheduled.
The operation led Berlusconi to cancel a meeting on Tuesday with Israeli Foreign Minister Avigdor Lieberman.
Today's operation "became necessary to restore the anatomy and jaw function that had been gravely compromised" in the attack, the AP said, citing the statement.
The accused attacker, Massimo Tartaglia, was determined to be unfit to stand trial on charges of aggravated assault, the said. A judge said that Tartaglia was unaware of his actions.
Tartaglia was ordered to remain under observation for another year in a psychiatric hospital, the BBC said. He had a history of psychological problems, according to the AP.