Integration of functional electrical stimulation during robotic-assisted intervention to increase bone mineral...

A spinal cord injury (SCI) leads to an alteration of the central nervous system which significantly impacts the health, function and quality of life of those affected. Since SCI leads to a loss lower limbs usage, sublesional osteoporosis is a common and established consequence with high risk of fracture in this population. The mechanical loading remains the most effective approach to stimulate physiologic bone remodeling. Furthermore, functional electrical stimulation, by producing active muscle contractions, would also increase bone mineral density. Combining functional electrical stimulation (FES) with mechanical stress during functional task such as walking or cycling would provide better results on BMD.

This case report describes a 64-years old man with a chronic complete SCI (T2-T3; AIS A) who was gradually exposed to mechanical stress (walking robot, standing, bicycle) coupled with FES for 26 months. Bone mineral density of the femoral head (BMDf) was defined at 3 different time points (baseline, after 10 and 26 months). The Fracture Risk Assessment Tool (FRAX) was used to calculate T-scores based on BMDf. Before the intervention, BMDf indicated severe osteoporosis in this man. After 10 months of combined intervention, the BMDf decreased to reach the level of osteopenia after 26 months.

The implementation of an intervention combining weight-bearing during robotic-assisted walking and FES would improve bone mineral density and could reduce the risk of fracture in people with complete SCI.