Paraplegia quite challenging at first for those with a spinal cord injury (SCI). With the aid of physiotherapists and occupational therapists, individuals with an SCI can learn new skills and adapt previous ones to maximize independence, often living independently within the community. Olfactory ensheathing cells (OEC) have been transplanted with success into the spinal cord of Polish man named Darek Fidyka, who was the victim of a knife attack that left him paraplegic in 2010. In 2014, Fidyka underwent pioneering spinal surgery that used nerve grafts, from his ankle, to 'bridge the gap' in his severed spinal cord and OEC's to
Dorsal nerve cord tubes. The process by which this is performed is called invagination. The cells essentially convolute into the body cavity, arranging themselves on the dorsal plane above the notochord, as mentioned above. The evolutionary explanation to this adaptation from a solid cord to hollow tube is unknown. In vertebrates, the dorsal nerve cord is modified into the central nervous system, which comprises the brain and spinal cord. Dorsal means the "back" side, as opposed to ventral which is the "belly" side of an organism. In bipedal organisms dorsal is the back and ventral is the front. In organisms which walk on