Frotzler Angela, Berger Markus, Knecht Hans, Eser Prisca
Swiss Paraplegic Research, CH-6207 Nottwil, Switzerland.
Bone. 2008 Sep;43(3):549-55. doi: 10.1016/j.bone.2008.05.006. Epub 2008 May 16.
Spinal cord injury (SCI) is associated with a marked and rapid sublesional bone loss. So far, reports about the time course of adaptive changes in bone mass and structure in people with chronic and complete SCI are conflicting. Both, a continuous decline of bone parameters throughout the chronic phase of immobilisation as well as stabilisation of bone status on a low level have been documented. In our recently published cross-sectional study we suggested that subjects with a complete SCI reach a new bone steady-state in the paralysed limbs after extensive bone loss was complete. In addition, we described a time loss curve for each measured bone mineral density and geometry parameter and calculated its individual time to reach steady-state (tsteady-state). The aim of the present study was to test the findings of our cross-sectional study in a longitudinal design. Thirty-nine male subjects of the original cross-sectional study with complete SCI and paralysis duration between 0.9 and 34 years were included. Two follow-up pQCT measurements at 15 and 30 months after baseline measurement were performed at the distal epiphyses and mid shafts of the femur, tibia and radius. From the epiphyseal scans, bone mass, trabecular and total BMD were calculated. From the shaft scans, bone mass and cortical BMD, total and cortical cross-sectional areas and cortical thickness were determined. Repeated measures ANOVAs were performed with bone data at baseline, after 15 months and 30 months. Analyses were performed including only subjects with a lesion duration > or =t(steady-state) for each particular bone parameter. Bone parameters of tibial and femoral epi- and diaphyses were found to show no statistically significant differences between the three time points. Relative changes in bone parameters were small and ranged from -1.72% to +0.51% in the femur and from -1.67% to +0.42% in the tibia within 30 months of monitoring. Our data confirm the temporal limitation of the bone loss after complete SCI with stabilisation of BMD and geometric properties on a lower level-a finding of clinical importance considering the treatment strategies of bone loss after SCI with respect to lesion duration.
脊髓损伤(SCI)与显著且快速的损伤节段以下骨质流失有关。到目前为止,关于慢性完全性脊髓损伤患者骨量和结构适应性变化的时间进程的报道相互矛盾。既有记录显示在整个慢性制动期骨参数持续下降,也有记录显示骨状态在低水平保持稳定。在我们最近发表的横断面研究中,我们提出完全性脊髓损伤患者在广泛的骨质流失完成后,瘫痪肢体达到了新的骨稳态。此外,我们描述了每个测量的骨矿物质密度和几何参数的时间损失曲线,并计算了其达到稳态的个体时间(t稳态)。本研究的目的是在纵向设计中验证我们横断面研究的结果。纳入了原始横断面研究中的39名男性受试者,他们患有完全性脊髓损伤,瘫痪持续时间在0.9至34年之间。在基线测量后15个月和30个月,对股骨、胫骨和桡骨的远端骨骺和骨干中部进行了两次随访外周定量CT测量。从骨骺扫描中计算骨量、小梁骨和总骨密度。从骨干扫描中确定骨量和皮质骨密度、总横截面积和皮质厚度。对基线、15个月和30个月时的骨数据进行重复测量方差分析。仅对每个特定骨参数损伤持续时间>或=t(稳态)的受试者进行分析。发现胫骨和股骨骨骺及骨干的骨参数在三个时间点之间没有统计学上的显著差异。在30个月的监测期内,股骨的骨参数相对变化较小,范围为-1.72%至+0.51%,胫骨为-1.67%至+0.42%。我们的数据证实了完全性脊髓损伤后骨质流失的时间局限性,骨密度和几何特性在较低水平保持稳定——考虑到脊髓损伤后骨质流失的治疗策略与损伤持续时间的关系,这一发现具有临床重要性。