Low Magnitude Mechanical Loading Is Osteogenic in Children With Disabling Conditions

Abstract

The osteogenic potential of short durations of low-level mechanical stimuli was examined in children with disabling conditions. The mean change in tibia vTBMD was ؉6.3% in the intervention group compared with ؊11.9% in the control group. This pilot randomized controlled trial provides preliminary evidence that low-level mechanical stimuli represent a noninvasive, non-pharmacological treatment of low BMD in children with disabling conditions. Introduction: Recent animal studies have demonstrated the anabolic potential of low-magnitude, high-frequency mechanical stimuli to the trabecular bone of weight-bearing regions of the skeleton. The main aim of this prospective, double-blind, randomized placebo-controlled pilot trial (RCT) was to examine whether these signals could effectively increase tibial and spinal volumetric trabecular BMD (vTBMD; mg/ml) in children with disabling conditions. Materials and Methods: Twenty pre-or postpubertal disabled, ambulant, children (14 males, 6 females; mean age, 9.1 Ϯ 4.3 years; range, 4 -19 years) were randomized to standing on active (n ϭ 10; 0.3g, 90 Hz) or placebo (n ϭ 10) devices for 10 minutes/day, 5 days/week for 6 months. The primary outcomes of the trial were proximal tibial and spinal (L 2 ) vTBMD (mg/ml), measured using 3-D QCT. Posthoc analyses were performed to determine whether the treatment had an effect on diaphyseal cortical bone and muscle parameters. Results and Conclusions: Compliance was 44% (4.4 minutes per day), as determined by mean time on treatment (567.9 minutes) compared with expected time on treatment over the 6 months (1300 minutes). After 6 months, the mean change in proximal tibial vTBMD in children who stood on active devices was 6.27 mg/ml (ϩ6.3%); in children who stood on placebo devices, vTBMD decreased by Ϫ9.45 mg/ml (Ϫ11.9%). Thus, the net benefit of treatment was ϩ15.72 mg/ml (17.7%; p ϭ 0.0033). In the spine, the net benefit of treatment, compared with placebo, was ϩ6.72 mg/ml, (p ϭ 0.14). Diaphyseal bone and muscle parameters did not show a response to treatment. The results of this pilot RCT have shown for the first time that low-magnitude, high-frequency mechanical stimuli are anabolic to trabecular bone in children, possibly by providing a surrogate for suppressed muscular activity in the disabled. Over the course of a longer treatment period, harnessing bone's sensitivity to these stimuli may provide a non-pharmacological treatment for bone fragility in children.

Pompe disease diagnosis and management guideline

“…Seating systems in adapted strollers or wheelchairs are critical to prevent or minimize contracture and deformity, especially spinal deformity, and should include a solid seat and back, hip guides, lateral trunk supports, knee adductors, and head support as needed, and as individually assessed. Supported standing is considered beneficial to prevent or minimize osteoporosis82 and may include the use of supine, prone, vertical and hydraulic standers or the use of power standing capabilities on motorized wheelchairs. Power tilt, recline and elevating leg rests on motorized wheelchairs can allow independent position change and weight shift for assistance in minimizing contracture and maintaining skin integrity.…”

Molecular pathways mediating mechanical signaling in bone

“…Evaluating those in the highest quartile of compliance, placebo controls lost 2% in femoral neck density over the year, while the treatment group lost no BMD indicating a statistical relative benefit of treatment. In a parallel study, twenty children with cerebral palsy were randomized into active mechanical treatment (0.3 g, 90 Hz, ten min per day) and placebo control groups (Ward et al, 2004). After six months, the placebo controls lost 12% of volumetric trabecular bone mineral density, while those in the active treatment arm gained 6.3%.…”

Skeletal abnormalities in neurofibromatosis type 1: Approaches to therapeutic options

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