The 19-year-old came off worse in a challenge with Radja Nainggolan in the first half of the stalemate against Rudi Garcia's side.
Juventus teenager Mattiello fractured the tibia and fibula in his right leg and remains in hospital following a two-hour operation on Sunday.
A statement on Chievo's official website said: "Chievo Verona announces that the surgery that was performed on the player Federico Mattiello was perfectly successful .
"The player will remain under observation in the Department of Orthopedics Hospital Sacred Heart of Negrar and will be constantly monitored prior to a permanent prognosis."
Matiello tweeted from hospital: "I thank everyone for the many messages, which give me the strength to look ahead!!!"
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