Shriners Hospitals for Children, 3101 SW Sam Jackson Park Road, Portland, OR, 97229, USA.
Spine Deform. 2021 May;9(3):645-653. doi: 10.1007/s43390-020-00262-7. Epub 2021 Jan 5.
Prospective comparative study.
Evaluate the correlation of CXM with established measures of growth. Theoretically higher CXM levels would correlate with rapid longitudinal bone growth and lower levels with growth cessation. Assessment of growth status in patients with pediatric spinal deformity is critical. The current gold standards for assessing skeletal maturity are based on radiographic measures and have large standard errors (SE). Type X collagen (COLX) is produced in the growing physis during enchondral ossification. CXM is a COLX breakdown product that can be measured in blood products. CXM, thus, is a direct measure of enchondral ossification.
IRB-approved prospective study. Q6mo anthropometrics and spine PA biplanar slot scanner images including the hand were assessed for major Cobb, Risser score (RS), triradiate cartilage status (TRC), Greulich and Pyle bone age (BA), and Sanders Score (SS). Serial dried blood spots (DBS) to obtain CXM levels were collected 3 consecutive days Q1-2 months based on SS.
47 idiopathic scoliosis patients, Cobb ≥ 20 were enrolled. Mean enrollment age was 11.8 years (range 7.1-16.6 years). 3103 DBS samples were assayed in quadruplicate. CXM results were highly reproducible with a 3% intraassay coefficient of variation (CV), and 12% interassay CV%. The CXM 3-day average was significantly correlated with BA R = 0.9, p < 0.001, RS R = 0.6, p < 0.001, SS R = 0.7, p < 0.001 and with height R = 0.7, p < 0.001. No patient with a CXM level < 5 ng/ml had remaining growth.
CXM is the first identifiable biomarker specific to longitudinal bone growth. Early results indicate that it is a patient-specific, real-time measure of growth velocity with high correlation to the established anthropometric and radiographic measures of growth. It is predictive of cessation of growth. It is highly reproducible with a low SE. Long-term follow-up is required to determine the ability of CXM to guide clinical decision-making.
前瞻性对比研究。
评估 CXM 与既定生长指标的相关性。理论上，较高的 CXM 水平与纵向骨骼快速生长相关，而较低的水平与生长停止相关。评估患有儿科脊柱畸形的患者的生长状态至关重要。目前，评估骨骼成熟度的金标准基于放射学测量，具有较大的标准误差 (SE)。X 型胶原 (COLX) 在软骨内成骨过程中产生于生长骺。CXM 是 COLX 降解产物，可在血液制品中测量。因此，CXM 是软骨内成骨的直接测量指标。
IRB 批准的前瞻性研究。每 6 个月进行一次人体测量学和脊柱 PA 双平面插槽扫描仪（包括手部）评估，以获得主要 Cobb、Risser 评分 (RS)、三射线软骨状态 (TRC)、Greulich 和 Pyle 骨龄 (BA) 和 Sanders 评分 (SS)。根据 SS，连续 3 天采集 3 个连续的干血斑 (DBS) 以获得 CXM 水平，每 1-2 个月采集 1 次。
共纳入 47 例 Cobb≥20 的特发性脊柱侧凸患者。平均入组年龄为 11.8 岁（范围 7.1-16.6 岁）。3103 个 DBS 样本进行了四重分析。CXM 结果具有高度可重复性，日内变异系数为 3%，日间变异系数为 12%。CXM 3 天平均值与 BA 呈显著相关（R=0.9，p<0.001），与 RS（R=0.6，p<0.001）、SS（R=0.7，p<0.001）和身高（R=0.7，p<0.001）呈显著相关。没有 CXM 水平<5ng/ml 的患者仍有生长。
CXM 是第一个可识别的纵向骨骼生长特异性生物标志物。早期结果表明，它是一种患者特异性的实时生长速度测量指标，与生长的既定人体测量学和放射学测量指标高度相关。它可以预测生长停止。它具有高度的可重复性，标准误差低。需要进行长期随访以确定 CXM 指导临床决策的能力。
