Transmission of low-intensity vibration through the axial skeleton of persons with spinal cord injury as a potential intervention for preservation of bone quantity and quality

Abstract

Background/objective: Persons with spinal cord injury (SCI) develop marked bone loss from paralysis and immobilization. Low-intensity vibration (LIV) has shown to be associated with improvement in bone mineral density in post-menopausal women and children with cerebral palsy. We investigated the transmissibility of LIV through the axial skeleton of persons with SCI as an initial approach to determine whether LIV may be used as a clinical modality to preserve skeletal integrity. Methods: Transmission of a plantar-based LIV signal (0.27 ± 0.11 g; 34 Hz) from the feet through the axial skeleton was evaluated as a function of tilt-table angle (15, 30, and 45°) in seven non-ambulatory subjects with SCI and ten able-bodied controls. Three SCI and five control subjects were also tested at 0.44 ± 0.18 g and 34 Hz. Transmission was measured using accelerometers affixed to a bite-bar to determine the percentage of LIV signal transmitted through the body. Results: The SCI group transmitted 25, 34, and 43% of the LIV signal, and the control group transmitted 28, 45, and 57% to the cranium at tilt angles of 15, 30, and 45°, respectively. No significant differences were noted between groups at any of the three angles of tilt. Conclusion: SCI and control groups demonstrated equivalent transmission of LIV, with greater signal transmission observed at steeper angles of tilt. This work supports the possibility of the utility of LIV as a means to deliver mechanical signals in a form of therapeutic intervention to prevent/reverse skeletal fragility in the SCI population.

Bone architecture adaptations after spinal cord injury: impact of long-term vibration of a constrained lower limb

“…Several studies of vibratory loading in humans with SCI have used whole-body vibration (WBV), in which the participants stand atop a vibrating platform [16–18]. The two studies which included bone assessments showed no effect of WBV training on BMD or trabecular micro-architecture [17, 18].…”

Weight Bearing Through Lower Limbs in a Standing Frame with and Without Arm Support and Low-Magnitude Whole-Body Vibration in Men and Women with Complete Motor Paraplegia

“…However, in order to better understand whether a standing intervention would be of potential merit, it would be useful to quantify what actual loads are being borne through the lower extremities of individuals with SCI while standing, as it is these loads that are expected to have an effect on the prevention of soft tissue contractures and bone loss. Such loads have been determined in persons with SCI at varying degrees of tilt when using a tilt table, although not at a fully upright position (4). Nevertheless, this information would not likely be directly translatable to loads experienced when using a standing frame, due to the full body contact that occurs with the tilt table or to the potential effect of arm support when using a standing frame.…”

Neurological Osteoporosis in Disabilities

“…Seven non-ambulatory subjects with SCI and ten able-bodied controls underwent transmission of a plantar-based LIV signal (0.27 +/-0.11 g; 34 Hz) from the feet through the axial skeleton as a function of tilt-table angle (15, 30, and 45 degrees). SCI subjects and controls demonstrated equivalent transmission of LIV, with greater signal transmission observed at steeper angles of tilt which supports the possibility of the utility of LIV as a means to deliver mechanical signals in a form of therapeutic intervention to prevent/reverse skeletal fragility in the SCI population (Asselin et al, 2011).…”