Alex Zanardi has been moved back to an intensive care unit at San Raffaele hospital, Milan, just days after being transferred to a specialised rehabilitation centre.

    Zanardi was seriously injured in a handbike accident near Siena in June and taken to hospital with severe head injuries. He has undergone three neurological surgeries and was kept in an induced coma.

    On Tuesday, medical staff from the Santa Maria alle Scotte hospital, Siena, announced that he would be transferred to a specialised recovery and functional rehabilitation centre in Lecco, northern Italy.

    MILAN, ITALY - JULY 18:  People walk by the San Raffaele Hospital on July 18, 2011 in Milan, Italy.
    San Raffaele Hospital, Milan, where Alex Zanardi is now being treated

    But on Friday, per Reuters, doctors at the Villa Beretta rehabilitation clinic released a statement saying that Zanardi's condition was unstable and as a result he was being returned to intensive care at the San Raffaele Hospital, just south of the rehabilitation clinic, in Milan.

    The 53-year-old raced for Jordan, Minardi, Lotus and Williams in F1, and won two CART championship titles in America, before a shocking racing acccident in Germany in 2001 resulted in his legs being amputated.

    Remarkably, he recovered and returned to racing with specially adapted cars, and also took up handbike racing, winning an astonishing four gold medals at the Paralympics and inspiring millions around the world in the process.