Zanardi, who won two golds at both London 2012 and Rio 2016 in para-cycling, was competing in a national handcycling road race in Italy when he crashed on a descent.

He was airlifted to hospital and underwent three hours of neurosurgery and facial surgery before being placed in a medically induced coma.

Dr Giuseppe Olivieri, head of neurosurgery at Siena's Santa Maria alle Scotte hospital revealed Zanardi was stable but remains in the coma. 

"Zanardi is in a stable condition and the parameters are stable too," he said, as reported by Sky Sports. 

"This is what we can expect at best at the moment.

"It will take a long time. 

"He will remain sedated for another 10 to 15 days. 

"At present, his response is good."

Olivieri also suggested Zanardi could remain in a coma for longer than expected, or come out sooner than first thought. 

"We do not know to which extent his coma is due to medications and to his medical conditions," he said.

"As I have said many times in the last few days, there is a primary damage that takes place when the trauma happens, and a secondary damage that are the consequences of this trauma.

"These are the metabolic consequences, which are remarkable. 

"These consequences can be extended for 10-15 days, they are corrected by medications and by sedation - they are fundamental.

"We can't think of interrupting these important therapies because we are curious to know which is the current physical state."

Zanardi, 53, competed in Formula One and sportscar racing during the 1990s.

In 2001, while competing in cart racing, he suffered a life-changing accident in which he lost both his legs.

Following his accident, Zanardi was fitted with two prosthetic limbs and after competing at the World Touring Car Championship turned to Para-cycling.