An implantable neuroprosthesis for standing and walking in paraplegia: 5-year patient follow-up.
We present the results of a 5-year patient follow-up after implantation of an original neuroprosthesis. The system is able to stimulate both epimysial and neural electrodes in such a way that the complete flexor-extensor chain of the lower limb can be activated without using the withdrawal reflex. We demonstrate that standing and assisted walking are possible, and the results have remained stable for 5 years. Nevertheless, some problems were noted, particularly regarding the muscle response on the epimysial channels. Analysis of the electrical behaviour and thresholds indicated that the surgical phase is crucial because of the sensitivity of the functional responses to electrode placement. Neural stimulation proved to be more efficient and more stable over time. This mode requires less energy and provides more selective stimulation. This FES system can be improved to enable balanced standing and less fatiguing gait, but this will require feedback on event detection to trigger transitions between stimulation sequences, as well as feedback to the patient about the state of his lower limbs.
Guiraud
David
D
INRIA-DEMAR Project, LIRMM, 161 Rue Ada, F-34392 Montpellier Cedex 5, France. David.Guiraud@lirmm.fr
Stieglitz
Thomas
T
Koch
Klaus Peter
KP
Divoux
Jean-Louis
JL
Rabischong
Pierre
P
D000328:Adult; D000703:Analog-Digital Conversion; D001642:Bicycling; D002516:Ceramics; D004599:Electric Stimulation Therapy / Q000295:instrumentation*; D004567:Electrodes, Implanted; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008838:Microcomputers; D009068:Movement / Q000502:physiology*; D009119:Muscle Contraction / Q000502:physiology; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology; D010264:Paraplegia / Q000628:therapy*; D010809:Physical Fitness / Q000502:physiology; D019736:Prostheses and Implants; D011474:Prosthesis Design; D019919:Prosthesis Implantation; D012825:Silicon; D012984:Software; D014025:Titanium; D016138:Walking / Q000502:physiology*
D014025:Titanium; D012825:Silicon