Though he was not born like that but developed that when he was diagnosed of transverse myelitis, an inflammation across the spinal cord, that paralysed him while in school. (vanguardngr.com)
The most common parasite that causes parasitic myelitis in dogs is Baylisascaris procyonis. (dogcare.dailypuppy.com)
His history precluded amputation because of severe degenerative myelitis, (some dogs have had a previous bilateral knee surgery) and hip dysplasia. (homevet.com)