The Polish doctors who performed the revolutionary treatment that allowed a paralysed man to walk again said Wednesday they were looking for new candidates, as their patient described how the medical procedure has changed his life.

Darek Fidyka, 40, was paralysed from the chest down by a knife attack but can now walk using a frame after nerve cells were transplanted into his severed spinal column in Poland.

"I hope to recover further," said Fidyka alongside his doctors at a press conference in the southwestern city of Wroclaw a day after the research behind the breakthrough treatment was published in the journal Cell Transplantation.

"I could live alone. I drive my car. True, it's been adapted, but I do drive it," he said, tears welling up in his eyes.

Wlodzimierz Jarmundowicz, who heads neurosurgery at the Polish clinic where the operation was carried out, however cautioned against raising "the hopes of every person with a damaged spine".

The treatment can only be applied to "injuries caused by a sharp instrument, like a machete," he said.

Pawel Tabakow, who led the team of surgeons in the medical procedure, said that the injury "is very rare".

They are now looking for two more patients suffering from similar injuries from across the world.

The criteria will be posted online in Polish on the website of the Akron Neuro-Rehabilitation Centre in Wroclaw where Fidyka was recovering.

An English version will go up on the website of the University College London's Institute of Neurology, whose British research team collaborated on the project.

Tabakow said it was chance that led him towards the revolutionary treatment.

He said that doctors generally take the cells that are supposed to promote nerve regeneration straight from the patient's nose. But that was not possible in Fidyka's case because of sinus inflammation.

Instead, they transplanted cells from his olfactory bulb, which required them to open up his skull.

The doctors showed video footage of Fidyka before surgery and several months after. One scene showed the former fireman kicking a ball.