Sandro returned to London earlier this week after suffering the injury on international duty with Brazil at the Copa America in Argentina and went in for the operation on Friday.
The 22-year-old will miss the start of the Premier League season while he recovers and a statement on Tottenham's website confirmed: "Following consultation with an independent knee specialist, Sandro underwent surgery on his left knee in London.
"Sandro withdrew from Brazil's Copa America campaign on Tuesday due to injury with scans confirming he had torn his lateral meniscus, as well as suffering a calf strain.
"The specialist has advised a three-month rehabilitation period before a return to full training."
Sandro was sent for a scan after complaining of pains in both his calves and his knee in training with Brazil.
Results initially showed the midfielder had ruptured the meniscus in his left knee -- an injury which requires surgery and usually takes around a month to heal -- but specialists delivered a worse prognosis for Spurs and he will be out for three months.
Sandro has become a popular figure at White Hart Lane since his move to the club in March 2010.
The Brazilian, who signed from Internacional, played 26 times for Harry Redknapp's team last term, and made his international debut in 2009.
Source: AFP
Source: AFP