MILAN - Prime Minister Silvio Berlusconi underwent bone transplant surgery on Monday to repair damage to his jaw and teeth when he was assaulted in 2009 by a man who threw a souvenir at him, his office said.

Italian Prime Minister Silvio Berlusconi shows his teeth during a news conference at Chigi palace in Rome, in this file picture taken February 9, 2011. Berlusconi underwent bone transplant surgery on March 7, 2011, to repair damage to his jaw and teeth when he was assaulted in 2009 by a man who threw a souvenir at him, his office said. Berlusconi suffered a broken nose, fractured teeth and gashed lips after being hit in the face by a spiked souvenir, a small model of the cathedral of Milan in December 2009.  [Photo/Agencies]

Related readings:  Italy's Silvio Berlusconi unwittingly features in pet desexing ad campaign  Mired in scandal, Berlusconi faces tax fraud trial  Berlusconi to face trial over sex scandal

A statement said the four-hour operation was carried out in Milan and was necessary so he could properly chew and move his jaw.

Berlusconi suffered a broken nose, fractured teeth and gashed lips after being hit in the face by a spiked souvenir, a small model of the cathedral of Milan in December, 2009.

The assailant, Massimo Tartaglia, had a history of mental illness.