Chiari畸形伴胸椎侧凸患者两侧肋骨长度差异及其与剃刀背畸形的相关性

Correlation of rib length asymmetry and rib hump deformity in patients with thoracic scoliosis secondary to Chiari malformation

目的：评估Chiari畸形伴胸椎侧凸患者两侧肋骨长度的差异及其与剃刀背畸形的相关性，探讨两侧肋骨生长的差异性是否为继发性改变。方法：选取Chiari畸形伴脊柱侧凸（scoliosis secondary to Chiari malformation，SSCM）患者38例（SSCM组），年龄9~17岁（12.3±3.6岁），身高155.4±10.8cm，Cobb角26°~ 108°（44.9°±23.5°）；顶椎位于T7~T9。另选58例青少年特发性脊柱侧凸（AIS）患者作为对照，均为右胸弯，年龄10~18岁（13.7±2.6岁），身高157.6±11.5cm，Cobb角28°~102°（43.9°±17.2°），顶椎位于T7~T9。剃刀背畸形角（rib hump，RH）均使用Scoliometer测量，采用螺旋CT三维重建的方法（volume viewer workstation）测量所有患者凹凸侧12对肋骨的长度，比较两组患者顶椎区、上下端椎及非侧凸区两侧肋骨的长度，分析顶椎区肋骨的对称性及其与Cobb角和RH的相关性。结果：SSCM组患者顶椎区（顶椎、顶椎上一椎体及顶椎下一椎体）凹侧肋骨长度显著大于凸侧（P〈0.01），而上下端椎及非侧凸区两侧肋骨长度无显著性差异（P〉0.05），RH为12.7°±4.0°；AIS组患者顶椎区（顶椎上一椎体、顶椎及顶椎下一椎体）凹侧肋骨长度也显著大于凸侧（P〈0.01），其程度与Chiari畸形组无显著性差异（P〉0.05），RH为11.9°±3.5°。顶椎区肋骨的不对称性与Cobb角大小呈显著性正相关关系（SSCM组：r=0.562，P=0.001；AIS组：r=0.463，P=0.003）；与RH亦呈显著相关性（SSCM组：r=0.373，P=0.01；AIS组：r=0.328，P=0.02）。结论：SSCM患者主胸弯顶椎区两侧肋骨长度不对称，且不对称程度和剃刀背畸形相关，其不对称性特征与AIS患者一致，其可能是脊柱侧凸在生长期发病后的继发性改变。

Objectives： To evaluate the rib length asymmetry in patients with thoracic scoliosis secondary to Chiari malformation and to correlate it to rib hump（RH） deformity, so as to elucidate whether the rib length asymmetry is primary or secondary. Methods： There were 38 patients in the group of scoliosis secondary to Chiari malformation（SSCM, group A） with a mean Cobb angle of 44.9°±23.5°（range, 26°-108°）, a mean age of 12.3±3.6 years（range, 9-17yrs）, a mean height of 155.4±10.8cm and the apical vertebrae ranging from T7 to T9. There were 58 patients in AIS group（group B） with a mean Cobb angle of 43.9°±17.2° （range, 28°-102°）, a mean age of 13.7±2.6 years（range, 10-18yrs） and a mean height of 157.6±11.5cm. All AIS patients had a major thoracic curve, and the apical vertebrae ranged from T7 to T9. Rib hump was measured with scoliometer. The length of all ribs was measured from the tip of costal head to the end of the same rib by built-in software on spiral computed tomography. The rib length discrepancy was compared between concave and convex sides at apical vertebral level, end vertebral level and no scoliosis levels. The correlation of rib length discrepancy with the magnitude of the Cobb angle and RH at apical vertebral level. Results： At the levels of the apical vertebrae, the vertebrae above and below the apex, the mean rib length was significantly bigger in the concave side in both SSCM group and AIS group（P〈0.01）, with no difference observed at the end vertebral level. The RH averaged at 12.7°±4.0° and 11.9°±3.5° in SSCM group and AIS group, respectively. The rib length discrepancy between concave and convex sides at apical vertebral level was significantly correlated with the magnitude of the Cobb angle and RH in both AIS and SSCM groups（Cobb angle： for AIS group, r=0.463, P=0.003; for SSCM group, r=0.562, P=0.001; RH： for AIS group, r=0.328, P=0.02; for SSCM group, r=0.373, P=0.01）. Conclusions： Rib length asymmetry at the apex vertebral level is similar in both scoliotic groups, and significantly correlated with RH deformity, which points strongly to the fact that the rib length asymmetry in apical region is most likely secondary to the scoliosis deformity.