Morphomics Analysis Group, University of Michigan, Ann Arbor, Michigan, USA.
J Anat. 2022 Dec;241(6):1344-1356. doi: 10.1111/joa.13751. Epub 2022 Aug 25.
Rib fractures are a common and serious outcome of blunt thoracic trauma and their likelihood is greater in older individuals. Osteoporotic bone loss is a well-documented aging phenomenon with sex-specific characteristics, but within rib bones, neither baseline maps of regional thickness nor the rates of bone thinning with age have been quantified across whole ribs. This study presents such data from 4014 ribs of 240 adult subjects aged 20-90. A validated cortical bone mapping technique was applied to clinical computed tomography scans to obtain local rib cortical bone thickness measurements over the surfaces of ribs 2 through 11. Regression models to age and sex gave rates of cortex thinning in local zones and aggregated across whole ribs. The statistical parametric mapping provided these relationships regionally as a function of rib surface location. All models showed significant reductions in bone thickness with age (p < 0.01). Average whole-rib thinning occurred at between 0.011 to 0.032 mm/decade (males) and 0.035 to 0.043 mm/decade (females), with sex and age accounting for up to 37% of population variability (R ). Rates of thinning differed regionally and by rib, with the highest bone loss of up to 0.074 mm/decade occurring in mid-rib cutaneous and superior regions of ribs 2-6. Rates were consistently higher in females than males (significantly so across whole ribs but not all local regions) and were more pronounced in cutaneous, superior, and inferior rib aspects (average 0.025 mm/decade difference in ribs 4-8) compared to pleural aspects which had the thickest cortices but saw only minor differences in thinning rates by sex (0.045 mm/decade for females and 0.040 mm/decade for males). Regional analysis showed male and female bone thickness differences that were not statistically significant at 20 years of age (p > 0.05 across practically all regions) but subsequent cortex thinning meant that substantial pleural and cutaneous regions were thinner (p < 0.05) in females than males by 55 years of age. The techniques and results from this study can be applied to assess rib bone content loss in clinical settings across wide populations. Additionally, average cortex thickness results can be mapped directly to finite element models of the thorax, and regression results are used to modify such models to represent the ribs of men and women across their full adult lifespan.
肋骨骨折是钝性胸部创伤的常见且严重的后果，在老年人中更为常见。骨质疏松症是一种有据可查的与年龄相关的骨骼丢失现象，具有性别特异性特征，但在肋骨中，无论是整个肋骨的区域厚度基线图，还是随年龄发生的骨变薄率，都没有得到量化。本研究提供了 240 名年龄在 20 至 90 岁的成年人的 4014 根肋骨的此类数据。一种经过验证的皮质骨绘图技术被应用于临床计算机断层扫描，以获得肋骨 2 到 11 表面的局部肋骨皮质骨厚度测量值。针对年龄和性别进行回归模型，得出了局部和整个肋骨的皮质变薄率。统计参数映射以肋骨表面位置为函数，提供了这些关系的区域分布。所有模型均显示出与年龄相关的骨厚度显著降低（p<0.01）。整个肋骨的平均变薄发生在 0.011 至 0.032mm/decade（男性）和 0.035 至 0.043mm/decade（女性）之间，性别和年龄占人口变异性的 37%（R 2）。变薄率因区域和肋骨而异，最高可达 0.074mm/decade 的骨丢失发生在肋骨 2-6 的中肋骨皮区和上区。女性的骨丢失率始终高于男性（在整个肋骨和所有局部区域均有显著差异），在皮区、上区和下区更为明显（肋骨 4-8 的平均差异为 0.025mm/decade），而在胸膜区则差异较小（女性为 0.045mm/decade，男性为 0.040mm/decade）。区域分析表明，男性和女性在 20 岁时的骨厚度差异没有统计学意义（在几乎所有区域均为 p>0.05），但随后的皮质变薄意味着女性的大部分胸膜和皮区比男性更薄（p<0.05）在 55 岁时。本研究的技术和结果可应用于临床环境中对广泛人群的肋骨骨量丢失进行评估。此外，平均皮质厚度结果可直接映射到胸部的有限元模型，回归结果用于修改这些模型，以代表男性和女性的肋骨在其整个成年期。
