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Heterogeneity in microstructural deterioration following spinal cord injury
Ghasem-Zadeh, Ali Galea, Mary P. Nunn, Andrew Panisset, Maya Wang, Xiao-Fang Iuliano, Sandra Boyd, Steven K. Forwood, Mark R. Seeman, Ego
Ghasem-Zadeh, Ali
Galea, Mary P.
Nunn, Andrew
Panisset, Maya
Wang, Xiao-Fang
Iuliano, Sandra
Boyd, Steven K.
Forwood, Mark R.
Seeman, Ego
Abstract
Background
Modelling and remodelling adapt bone morphology to accommodate strains commonly encountered during loading. If strains exceed a threshold threatening fracture, modelling-based bone formation increases bone volume reducing these strains. If unloading reduces strains below a threshold that inhibits resorption, increased remodelling-based bone resorption reduces bone volume restoring strains, but at the price of compromised bone volume and microstructure. As weight-bearing regions are adapted to greater strains, we hypothesized that microstructural deterioration will be more severe than at regions commonly adapted to low strains following spinal cord injury.
Methods
We quantified distal tibial, fibula and radius volumetric bone mineral density (vBMD) using high-resolution peripheral quantitative computed tomography in 31 men, mean age 43.5 years (range 23.5‐75.0), 12 with tetraplegia and 19 with paraplegia of 0.7 to 18.6 years duration, and 102 healthy age- and sex-matched controls. Differences in morphology relative to controls were expressed as standardized deviation (SD) scores (mean ± SD). Standardized between-region differences in vBMD were expressed as SDs (95% confidence intervals, CI).
Results
Relative to controls, men with tetraplegia had deficits in total vBMD of −1.72 ± 1.38 SD at the distal tibia (p < 0.001) and − 0.68 ± 0.69 SD at distal fibula (p = 0.041), but not at the distal radius, despite paralysis. Deficits in men with paraplegia were −2.14 ± 1.50 SD (p < 0.001) at the distal tibia and −0.83 ± 0.98 SD (p = 0.005) at the distal fibula while distal radial total vBMD was 0.23 ± 1.02 (p = 0.371), not significantly increased, despite upper limb mobility. Comparing regions, in men with tetraplegia, distal tibial total vBMD was 1.04 SD (95%CI 0.07, 2.01) lower than at the distal fibula (p = 0.037) and 1.51 SD (95%CI 0.45, 2.57) lower than at the distal radius (p = 0.007); the latter two sites did not differ from each other. Results were similar in men with paraplegia, but total vBMD at the distal fibula was 1.06 SD (95%CI 0.35, 1.77) lower than at the distal radius (p = 0.004).
Conclusion
Microarchitectural deterioration following spinal cord injury is heterogeneous, perhaps partly because strain thresholds regulating the cellular activity of mechano-transduction are region specific.
Keywords
cortical -bone, HR-pQCT, microstructure, paralysis, spinal -cord -injury, trabecular bone, unloading, weight-bearing
Date
2021
Type
Journal article
Journal
Bone
Book
Volume
142
Issue
Page Range
1-8
Article Number
Article 115778
ACU Department
Mary MacKillop Institute for Health Research
Faculty of Health Sciences
Faculty of Health Sciences
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Relation URI
Source URL
Event URL
Open Access Status
License
All rights reserved
File Access
Controlled