Spinal cord injury bypass
Interesting question!

There has been at least one study that bypassed a spinal lesion site with autografted neuronal tissue (Tadie et al., 2004 - doi:10.1089/089771502320317069). The study participant regained voluntary motor skills 8 months after bypass surgery. The surgery involved the implantation of nerve autografts between the rostral spinal ventral horn and the caudal ventral roots. Regain of motor function was observed after the patient had been paralyzed for 3 years.