Michael Schumacher's surgeon has denied he recently carried out "experimental" treatment on the stricken Formula 1 legend.

Amid great secrecy about the 50-year-old former Ferrari and Mercedes driver's brain injuries, Schumacher was recently hospitalised in Paris under the care of cardiac expert professor Philippe Menasche.

The world's media speculated that the great German underwent experimental stem cell therapy.

"I do not work miracles," Menasche told the Italian newspaper La Repubblica.

"With my team, we are not doing any experiments. It's an abominable term that does not correspond with my vision of what medicine is."

For instance, Menasche said that a trial phase of a technique involving heart cell transfusion ended two years ago.

"There was an explosion of attention of our department, but the situation has already normalised," he explained.

"Everyone was looking out for me, but I did not do any experimental cures."

Referring to stem cell techniques in general, Menasche added: "There has been a lot of progress in the last 20 years, but the truth is that we still know very little."