After a third surgery, the hospital looking after Alex Zanardi says the former F1 driver's neurological condition remains "severe".
The Santa Maria Alle Scotte hospital in Siena, Italy, said the latest five-hour operation was for "cranio-facial reconstruction", after the 53-year-old recently crashed into a truck during a hand-cycling road race.
"The fractures were complex," said Professor Paolo Gennaro, director of maxillofacial surgery.
"This required careful work making use of computerised, digital and three-dimensional technologies made to measure for the patient," he added.
"The complexity of the case was rather unique, even if it is a type of fracture that we routinely face in our centre."
The hospital said Zanardi is still sedated and ventilated in intensive care with a "confidential" prognosis.