Department of Orthopaedic Surgery, Medical College of Wisconsin, 9200 West Wisconsin Avenue, Milwaukee, WI 53226, USA.
J Bone Joint Surg Am. 2013 Sep 4;95(17):e1241-7. doi: 10.2106/JBJS.L.01035.
The first cervical vertebra (C1) is a unique ring-shaped structure and is largely cartilaginous at birth. Our objectives were to retrospectively analyze the age of closure of the synchondroses and determine age-dependent morphological characteristics of the C1 vertebra using computed tomographic (CT) scans.
Helical CT scans were made in fifty-four children as part of routine imaging of patients presenting to the emergency room with head injury, to exclude cervical spine trauma. Axial and sagittal reconstruction images of the C1 ring were analyzed for widths of the anterior and posterior synchondroses, outer and inner anteroposterior diameters, outer and inner transverse diameters, inner area of the spinal canal at C1, and heights of the anterior and posterior arches. Variations in these parameters were evaluated in age groups from infancy to eighteen years.
As ossification progressed, the widths of the anterior neurocentral and posterior synchondroses decreased with increasing age. Closure of the posterior synchondrosis was complete in all by thirty-six months, except in one fifty-five-month-old subject in whom the posterior synchondrosis was open. Closure of the anterior synchondrosis was generally found after thirty-six months. Growth of the mean outer and inner anteroposterior diameters, mean outer transverse diameter, and increase in canal area occurred with age up to the three to six-year group, following which measurements increased minimally or stayed relatively constant. The inner transverse diameter was largely unchanged from birth to maturity and appeared to be independent of age. Anterior and posterior ring heights showed a similar distribution, with an increase up to the nine to twelve-year age group, and relatively constant values thereafter.
Data from this retrospective review of fifty-four CT scans of the cervical spine, weighted toward the youngest population, assist in understanding the age-dependent osseous anatomy and biomechanical stability of the C1 vertebra in the growing child, help to distinguish fractures from incomplete ossification, and help to formulate decisions on the use of internal fixation of C1 in the growing child.
第一颈椎（C1）是一种独特的环形结构，在出生时主要是软骨。我们的目的是回顾性分析骺融合的年龄，并使用计算机断层扫描（CT）确定 C1 椎骨的年龄依赖性形态特征。
54 名儿童在急诊室因头部受伤就诊进行常规成像检查时进行了螺旋 CT 扫描，以排除颈椎外伤。对 C1 环的轴向和矢状位重建图像进行分析，以评估前、后骺的宽度、外、内前后径、外、内横径、C1 椎管内面积和前、后弓的高度。在从婴儿到 18 岁的年龄组中评估这些参数的变化。
随着骨化的进行，前神经中骺和后骺的宽度随年龄的增长而减小。除了一名 55 个月大的儿童后骺未闭合外，所有儿童的后骺在 36 个月时均完全闭合。前骺一般在 36 个月后闭合。随着年龄的增长，外、内前后径的平均值、外横径的平均值和椎管面积的增加发生在 3 至 6 岁组，之后测量值增加很少或保持相对稳定。从出生到成熟，内横径基本不变，且与年龄无关。前、后弓高度的分布相似，在前 9 至 12 岁年龄组增加，之后相对稳定。
本研究回顾性分析了 54 例颈椎 CT 扫描的结果，偏向于最小年龄组，有助于理解生长中的儿童 C1 椎骨的年龄依赖性骨骼解剖结构和生物力学稳定性，有助于区分骨折与不完全骨化，并有助于制定在生长中的儿童中使用 C1 内固定的决策。
