Unfortunately, these types of devices will always be of limited usefulness for most pre-existing spinal cord patients. Why? - because after only a few months, most muscles have had permanent wasting, and joints have begun to contract, often permanent as well. Bones have undergone significant disuse osteopenia. Unless the patient has Christopher Reeve type resources, then the day to day intensive PT to mobilize limbs does not occur.
Even in young healthy patients, even having a cast on for 2 months results in permanent muscle loss.
Br J Sports Med. 2006 Jun; 40(6): 552–553.
Calf muscle wasting after tibial shaft fracture
M Khalid, A Brannigan, and T Burke