Wren Tishya A L, Aggabao Patricia C, Poorghasamians Ervin, Chavez Thomas A, Ponrartana Skorn, Gilsanz Vicente
Department of Orthopaedic Surgery, Children's Hospital Los Angeles, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America.
Departments of Radiology, Children's Hospital Los Angeles, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America.
PLoS One. 2017 Feb 28;12(2):e0172844. doi: 10.1371/journal.pone.0172844. eCollection 2017.
Lumbar lordosis (LL) is more prominent in women than in men, but the mechanisms responsible for this discrepancy are poorly defined. A recent study indicates that newborn girls have smaller vertebral cross-sectional area (CSA) when compared to boys-a difference that persists throughout life and is independent of body size. We determined the relations between vertebral cross-sectional area (CSA) and LL angle and whether sex differences in lumbar lordosis are related to sex differences in vertebral CSA. Using multi-planar magnetic resonance imaging (MRI), we measured vertebral cross-sectional area (CSA) and vertebral height of the spine of 40 healthy boys and 40 girls, ages 9-13 years. Measures of the CSA of the lumbar vertebrae significantly differed between sexes (9.38 ± 1.46 vs. 7.93 ± 0.69 in boys and girls, respectively; P < 0.0001), while the degree of LL was significantly greater in girls than in boys (23.7 ± 6.1 vs. 27.6 ± 8.0 in boys and girls, respectively; P = 0.02). When all subjects were analyzed together, values for LL angle were negatively correlated to vertebral CSA (r = -0.47; P < 0.0001); this was also true when boys and girls were analyzed separately. Multivariate regression analysis indicated that vertebral CSA was independently associated with LL, even after accounting for sex, age, height or vertebral height, and weight. Similar negative relations were present when thoracic vertebrae were analyzed (Model P < 0.0001, R2 = 0.37, thoracic vertebral CSA slope P < 0.0001), suggesting that deficient vertebral cross-sectional dimensions are not merely the consequence of the anterior lumbar curvature. We conclude that vertebral CSA is negatively associated with LL, and that the greater degree of LL in females could, at least in part, be due to smaller vertebral cross-sectional dimensions. Studies are needed to examine the potential relations between vertebral CSA and spinal conditions known to be associated with increased LL, such as spondylolysis and spondylolisthesis.
腰椎前凸（LL）在女性中比在男性中更明显，但造成这种差异的机制尚不清楚。最近一项研究表明，与男孩相比，新生女婴的椎体横截面积（CSA）较小——这种差异在一生中持续存在，且与体型无关。我们确定了椎体横截面积（CSA）与LL角之间的关系，以及腰椎前凸的性别差异是否与椎体CSA的性别差异有关。我们使用多平面磁共振成像（MRI）测量了40名9至13岁健康男孩和40名女孩脊柱的椎体横截面积（CSA）和椎体高度。腰椎椎体的CSA测量值在性别之间存在显著差异（男孩和女孩分别为9.38±1.46和7.93±0.69；P<0.0001），而女孩的LL程度明显大于男孩（男孩和女孩分别为23.7±6.1和27.6±8.0；P = 0.02）。当对所有受试者进行综合分析时，LL角的值与椎体CSA呈负相关（r = -0.47；P<0.0001）；当分别对男孩和女孩进行分析时也是如此。多变量回归分析表明，即使在考虑了性别、年龄、身高或椎体高度以及体重之后，椎体CSA仍与LL独立相关。对胸椎进行分析时也存在类似的负相关关系（模型P<0.0001，R2 = 0.37，胸椎椎体CSA斜率P<0.0001），这表明椎体横截面积不足不仅仅是腰椎前凸的结果。我们得出结论，椎体CSA与LL呈负相关，女性LL程度较高至少部分可能是由于椎体横截面积较小。需要开展研究来检验椎体CSA与已知与LL增加相关的脊柱疾病（如椎弓根峡部裂和腰椎滑脱）之间的潜在关系。
