The Italy international only returned to action at the start of the month, after suffering a hairline fracture of his right foot in September.
However, El Shaarawy continued to experience pain in his fourth metatarsal bone, forcing the player to have another operation that will see him miss the Rossoneri's Champions League last 16 tie with Atletico Madrid.
"AC Milan announces that Stephan El Shaarawy today [Saturday] underwent surgery on his right foot in Portugal," read a club statement.
"The procedure was necessary to stabilise the fourth metatarsal bone, thus preventing an overload on the area of the previous stress fracture and, at the same time, to stimulate the same area of the foot in order to obtain an absolute cure.
"Professor Niek van Dijk, who believes the surgery a complete success, also anticipates subsequent tests that will determine the best steps towards healing and suggested the resumption of athletic and physical conditioning in approximately 10 weeks."
El Shaarawy, who was also carrying a thigh problem at the start of the season, has been restricted to just four Serie A appearances this term.
