Alex Zanardi undergoes neurosurgery for a second time

Alex Zanardi has undergone a second round of neurological surgery 10 days after being admitted to hospital with severe head injuries sustained in a handbike road accident.

Officials from the Santa Maria alle Scotte Hospital in Siena, Italy, said in a medical bulletin the surgery took place on Monday and lasted two and a half hours. "Serious from a neurological point of view and the prognosis remains reserved".

Zanardi's clinical conditions remained stable on Tuesday afternoon, according to the latest press release issued by the hospital.

"The intervention carried out represents a step that had been hypothesised by the team", said Roberto Gusinu, the hospital's Health Director.

"Our professionals will evaluate the evolution of the situation day by day".

Zanardi was taking part in the "Obiettivo tricolore" relay race near Pienza, Tuscany when he lost control while descending and crossed lanes, colliding with a truck.

The 53-year-old Zanardi, who lost both of his legs in an auto racing crash almost 20 years ago, has been on a ventilator since he crashed his handbike into an oncoming truck near the Tuscan town of Pienza on June 19 during a relay event.

Zanardi, a former Formula One driver who had both his legs amputated after a motor racing accident two decades ago, suffered serious head injuries when he lost control of his handbike during a race on a Tuscan road almost two weeks ago and crashed into an oncoming truck.

Zanardi won four gold medals and two silvers at the 2012 and 2016 Paralympics.

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