Michael Schumacher's fans converged outside the French hospital where the injured former driver is fighting for his life following a skiing accident.BIRTHDAY VIGILSchumacher has been in a medically induced coma since December 29 2013 after he struck his head on a rock while on a family vacation. Busloads of fans from Italy and Paris headed to the hospital in Grenoble, France where he is being treated.The seven-time F1 champion has since undergone two brain operations. Doctors have refused to give a prognosis for Schumacher, saying they are focused on his immediate care.LONG WAIT AHEADInjured former Formula 1 driver Michael Schumacher could remain in a coma "for weeks or even months".That is the expert view of Professor Uwe Kehler, the highly respected head of neurosurgery at the Asklepios hospital in Hamburg.Kehler said: "Generally, it takes two to three weeks until a patient with such a severe trauma can be woken up. "It can take days or even weeks until the patient opens his eyes. Unfortunately, it is also possible that the person does not wake up properly."Schumacher is the most successful F1 driver in history, racking up a record 91 race wins. He retired in 2012.