In a scientific first, cells from a patient’s own body have been used to heal his spinal cord, allowing him to walk again. The procedure was carried out on Darek Fidyka, a 40-year-old Polish man who in 2010 fell victim to a knife attack that left him paralyzed from the chest down. Polish surgeons implanted olfactory cells from Fidyka’s nasal passage and nerve tissue from his ankle over the severed parts of his spinal cord to catalyze nerve growth and cell regeneration.