Implanted functional electrical stimulation: case report of a paraplegic patient with complete SCI after 9 years

Area of Science:

• Neuroscience and Biomedical Engineering
• Rehabilitation Technology
• Spinal Cord Injury Research

Background:

• A 9-year clinical and technological follow-up of a patient implanted with an 8-channel epimysial and 4-channel neural stimulation functional electrical stimulation (FES) neuroprosthesis.
• The study aimed to present long-term experiences and assess functional benefits of the FES device.

Observation:

• The patient continued using the FES system for nine years, a unique duration in similar studies.
• Significant variability in stimulation thresholds and induced muscle contraction quality was observed.
• Gait performance declined due to muscle fatigue and atrophy, despite the implant functioning correctly.

Findings:

• Neural stimulation pathways yielded better muscle response (MRC scale 4/5 in 3/5 muscles) compared to epimysial.
• Muscle fatigue and loss of muscle mass significantly impacted FES-induced gait performance.
• The FES device's core features remained stable over time, even after periods of disuse.

Implications:

• Muscle strength training is crucial to mitigate fatigue and maintain functional gains from FES.
• The study raises questions about the optimal approach: neural versus epimysial FES for lower limb restoration.
• Continuous clinical and technological monitoring is essential for long-term FES efficacy in spinal cord injury patients.