Physiological effects of lower extremity functional electrical stimulation in early spinal cord injury: lack of efficacy to prevent bone loss

Study design: Controlled, repeat-measures study. Objectives: To determine if functional electrical stimulation (FES) can affect bone atrophy in early spinal cordinjury (SCI), and the safety, tolerance and feasibility of this modality in bone loss remediation. Setting: Spinal Injuries Units, Royal Adelaide Hospital and Hampstead Rehabilitation Centre, South Australia. Methods: Patients with acute SCI (ASIA A - D) were allocated to FES (n = 23, 28 +/- 9 years, C4 - T10, 13 Tetra) and control groups (CON, n = 10, 31 +/- 11 years, C5 - T12, four Tetra). The intervention group received discontinuous FES to lower limb muscles (15 min sessions to each leg twice daily, over a 5-day week, for 5 months). Dual energy X-ray absorptiometry (DEXA) measured total body bone mineral density (tbBMD), hip, spine BMD and fat mass (FM) within 3 weeks, and 3 and 6 months postinjury. Results: FES and CO N groups' tbBMD differed significantly at 3 months postinjury (P < 0.01), but not thereafter. Other DEXA measures (hip, spine BMD, FM) did not differ between groups at any time. No adverse events were identified. Conclusion: Electrically stimulated muscle activation was elicited, and tetanic effects were reproducible; however, there were no convincing trends to suggest that FES can play a clinically relevant role in osteoporosis prevention (or subsequent fracture risk) in the recently injured patient. The lack of an osteogenic response in paralysed extremities to electrically evoked exercise during subacute and rehabilitation/recovery phases cannot be fully explained, and may warrant further evaluation.