Deparment of Kinesiology, University of Waterloo, 200 University Ave W, Waterloo, ON, N2L 3G1, Canada.
KITE, Toronto Rehabilitation Institute, University Health Network, Toronto, ON, M4G 3V9, Canada.
Osteoporos Int. 2021 Apr;32(4):759-767. doi: 10.1007/s00198-020-05705-5. Epub 2020 Oct 21.
People experience rapid bone loss shortly after a spinal cord injury (SCI), but the long-term bone changes are yet to be confirmed. This study showed that trabecular bone may have reached a steady state, whereas cortical bone continued to decline in people with a chronic SCI (mean time post injury: 15.5 ± 10 years).
(1) To explore changes in bone [primary measure: trabecular volumetric bone mineral density (vBMD); secondary measures: cortical vBMD, cortical thickness, cortical cross-sectional area (CSA), and polar moment of inertia] over 2 years in individuals with a chronic spinal cord injury (SCI). (2) To explore whether muscle density changes were potential correlates of the observed bone changes.
This study is a secondary data analysis of a prospective, observational study involving 70 people with a chronic SCI (≥ 2 years post injury). The study included 4 strata of participants with diverse impairments: (1) Paraplegia (T1-T12) motor complete American Spinal Injury Association Impairment Scale (AIS) A/B (n = 23), (2) Paraplegia motor incomplete AIS C/D (n = 11), (3) Tetraplegia (C2-C8) AIS A/B (n = 22), and (4) Tetraplegia AIS C/D (n = 14). Peripheral quantitative computed tomography scans were taken at the 4% (distal tibia), 38% (diaphyseal tibia), and 66% (muscle cross-sectional area) tibia sites by measuring from the distal to proximal tibia starting at the inferior border of the medial malleolus. The tibia sites were assessed annually over a span of 2 years. Comparisons were made using a paired-samples t test and simple linear regression was used to adjust for sex, time post injury, and bisphosphonate use.
We observed no changes in trabecular vBMD at the 4% tibia site, but there was a statistically significant decline in cortical vBMD, cortical thickness, and CSA at the 38% tibia site. Changes in muscle density were not associated with the decreases observed in cortical bone.
Our findings suggest that individuals with chronic SCI (mean duration of injury: 15.5 ± 10 years) may have reached a plateau in bone loss with respect to trabecular bone, but cortical bone loss can continue well into the chronic stages.
（1）探讨慢性脊髓损伤（SCI）患者 2 年内骨量的变化[主要指标：骨小梁体积骨密度（vBMD）；次要指标：皮质骨 vBMD、皮质厚度、皮质横截面积（CSA）和极惯性矩]。（2）探讨肌肉密度变化是否与观察到的骨变化有关。
本研究为前瞻性观察性研究的二次数据分析，纳入 70 名慢性 SCI（≥2 年）患者。研究包括 4 个不同损伤程度的参与者分层：（1）截瘫（T1-T12）运动完全美国脊髓损伤协会损伤量表（AIS）A/B（n=23）；（2）不完全性截瘫运动 AIS C/D（n=11）；（3）四肢瘫（C2-C8）AIS A/B（n=22）；（4）四肢瘫 AIS C/D（n=14）。通过从内踝下缘开始测量胫骨，从胫骨远端到近端，在胫骨的 4%（胫骨远端）、38%（骨干）和 66%（肌肉横截面积）处进行外周定量 CT 扫描。在 2 年内每年对胫骨部位进行评估。使用配对样本 t 检验进行比较，并使用简单线性回归调整性别、损伤后时间和双膦酸盐使用情况。
我们观察到胫骨 4%处的骨小梁 vBMD 没有变化，但胫骨 38%处的皮质 vBMD、皮质厚度和 CSA 呈统计学显著下降。肌肉密度的变化与皮质骨的减少无关。
我们的发现表明，慢性 SCI 患者（平均损伤时间：15.5±10 年）可能在骨小梁方面达到了骨丢失的平台期，但皮质骨丢失仍可继续进入慢性期。
