胸段先天性脊柱侧凸后路长节段矫形术后远端附加现象的危险因素分析

Risk factors of distal adding-on phenomenon after posterior correction of congenital thoracic deformity with long fusion

中文关键词:  先天性脊柱侧凸  远端冠状面失代偿  远端附加现象  长节段  独立危险因素

英文关键词:Congenital Scoliosis  Distal coronal decompensation  Adding-on phenomenon  Long segment  Risk factors

中文摘要:

  【摘要】 目的：研究胸段先天性脊柱侧凸（CS）患者行后路长节段矫形术后远端附加现象的发生率，分析其危险因素。方法：回顾性分析2006年4月~2016年4月我院收治的78例胸段CS后路长节段椎弓根螺钉系统矫形手术治疗的患者，其中男35例，女43例；年龄10~18岁，平均12.6±3.0岁。随访24~96个月，平均42.4±27.3个月。收集术前MRI资料及术前、术后及末次随访时站立位脊柱全长正位X线片，收集患者性别、年龄、Risser征、体重指数（BMI）、骨移植材料、融合节段，根据患者是否出现远端附加现象（末次随访时术后站立位脊柱全长正位X线片满足以下之一者：术后最下固定椎偏离骶骨中垂线10mm以上；最下固定椎以下第一个椎间隙成角增加5°以上；最下固定椎下第一个椎体偏离骶骨中垂线5mm以上），将患者分为远端附加现象组与非远端附加现象组。分别测量两组患者手术前后主弯Cobb角、主弯矫正幅度、头侧代偿弯Cobb角、尾侧代偿弯、冠状面平衡距离、冠状面平衡矫正距离、肩高度、顶椎偏距、远端固定椎位置、远端固定椎椎间隙成角、术后主弯/尾侧代偿弯比、椎间盘Pfirrmann分级等可能对远端附加现象发生有影响的因素。应用卡方检验、Fisher精确检验、t检验、Mann-Whitney U检验及多因素Logistic回归分析，分析远端附加现象的危险因素；应用ROC曲线分析发生远端附加现象相关危险因素的最佳截断点。结果：共7例发生冠状面远端附加现象，发生率为8.97%。两组比较，术前冠状面平衡距离（-0.3±1.6mm vs 2.3±2.7mm）、LIV是否触及稳定椎（59/12 vs 0/7）、术后主弯Cobb角（19.0°±7.8° vs 28.7°±9.5°）、术后头侧代偿弯Cobb角（5.9°±3.6° vs 9.1°±7.4°）、冠状面平衡矫正距离（-0.9±1.6mm vs 3.4±1.7mm）、术后LIV椎间隙成角（1.4°±1.7° vs 3.5°±3.1°）有统计学差异（P＜0.05），而性别比（32/29 vs 3/4）、年龄（12.5±2.8岁 vs 13.2±5.2岁）、Risser征比（18/53 vs 2/5）、体重指数（17.8±3.8kg/m2 vs 18.5±5.1kg/m2）、融合节段数（7.9±3.4个 vs 8.3±3.0个）、自体骨移植/人工骨移植（40/31 vs 4/3）、术前主弯Cobb角（47.4°±14.0° vs 55.1°±12.0°）、术前头侧代偿弯Cobb角（16.5°±12.6° vs 24.5°±13.7°）、术前尾侧代偿弯Cobb角（19.1°±12.3° vs 26.1°±14.3°）、术前肩高度（0.4±1.4mm vs 0.0±1.4mm）、术前顶椎偏距（1.7±2.7mm vs 2.0±2.7mm）、术前Pfirrmann分级（64/7 vs 4/3）及术后尾侧代偿弯Cobb角（5.9°±5.0° vs 8.4°±6.3°）、术后冠状面平衡距离（0.7±0.9mm vs -1.1±1.2mm）、术后肩高度（0.2±2.3mm vs 0.7±0.9mm）、术后顶椎偏距（1.0±1.2mm vs 2.2±1.8mm）、术后主胸弯/尾侧代偿弯比（5.8°±6.7° vs 6.8°±12.2°）、主弯矫正幅度（28.4°±17.0° vs 34.5°±15.1°）无统计学差异（P>0.05）；多因素Logistic回归分析显示，远端附加现象的独立危险因素是术后远端固定椎椎间隙成角过度（LIV disc angle）（OR=1.72，P=0.003），远端固定椎未触及稳定椎（OR=2.31，P=0.007），术后冠状面平衡矫正距离过度（pre-post CBD）（OR=1.21，P=0.014）。ROC曲线显示，术后LIV椎间隙成角最佳截断点为8.05°（敏感性71.4%，特异性81.7%，ROC曲线下面积为0.821，95%CI：0.669~0.972，P=0.005），冠状面平衡矫正距离最佳截断点为3.45cm（敏感性85.7%，特异性88.7%，ROC曲线下面积为0.915，95%CI：0.808~0.999，P<0.001）。结论：LIV未触及稳定椎、术后LIV椎间隙成角过大和术后冠状面平衡矫正距离过度是胸段先天性脊柱侧凸行后路长节段矫形术后远端附加现象的独立危险因素。

英文摘要:

  【Abstract】 Objectives: To investigate the incidence and risk factors of postoperative distal adding-on phenomenon after posterior correction of congenital thoracic deformity with long fusion. Methods: 78 patients were analyzed who underwent posterior pedicle screw correction with longfusion for congenital thoracic deformity from April 2006 to April 2016 in our hospital. There were 35 males and 43 females with a mean age of 12.6±2.9 years. The average follow-up was 42.4±27.3 months. All patients were categarized into adding-on group and non-adding-on group according to definiton of postoperative adding-on phenomenon. Factors which might cause adding-on phenomenon occurrence were collected: age, gender, Risser sign, body mass index, bone graft, segments, pre- and post-main thoracic cobb, cranial curve, caudal curve, coronal balance distance, pre-post coronal balance distance, radiographic shoulder height(RSH), apical vertebra translation(AVT). Chi-square test, Fisher exact test, t-test, Mann Whitney U test and multi-factor logistic regression analysis were used to investigate the correlation of possible risk factors and adding-on phenomenon; ROC curve analysis was used to determine the cut-off score between factors and adding-on. Results: Among the 78 patients, 7 cases (8.97%) presented with distal adding-on phenomenon. There were significant differences of pre-operative coronal balance distance(-0.3±1.6mm vs 2.3±2.7mm), LIV location(59/12 vs 0/7), post-operative main thoracic Cobb(19.0°±7.8° vs 28.7°±9.5°), post-operative cobb angle of caudal curve(5.9°±3.6° vs 9.1°±7.4°), pre-post coronal balance distance(-0.9±1.6mm vs 3.4±1.7mm), LIV disc angle(1.4°±1.7° vs 3.5°±3.1°) between the two groups in univariable test(P＜0.05). There were no signficant differences between two groups in gender(32/29 vs 3/4), age(12.5±2.8 years vs 13.2±5.2 years), Risser sign(18/53 vs 2/5), BMI(17.8±3.8kg/m2 vs 18.5±5.1kg/m2), segments(7.9±3.4 vs 8.3±3.0), bone graft(40/31 vs 4/3), pre-operative main thoracic Cobb(47.4°±14.0° vs 55.1°±12.0°), pre-operative cranial curve Cobb(16.5°±12.6° vs 24.5°±13.7°), pre-operative caudal curve cobb(19.1°±12.3° vs 26.1°±14.3°), pre-operative RSH(0.4°±1.4° vs 0.0°±1.4°), pre-operative AVT(1.7°±2.7° vs 2.0°±2.7°), Pfirrmann classification(64/7 vs 4/3), post-operative Cobb angle of caudal curve(5.9°±5.0° vs 8.4°±6.3°), post-operative coronal balance distance(0.7±0.9mm vs -1.1±1.2mm), post-operative RSH(0.2°±2.3° vs 0.7°±0.9°), post-operative AVT(1.0°±1.2° vs 2.2°±1.8°), post-operative ratio of major curve/caudal curve(5.8°±6.7° vs 6.8°±12.2°) and major curve correction(28.4°±17.0° vs 34.5°±15.1°, P>0.05). In multivariate logistic regression analysis between each two groups, postoperative LIV disc angle(OR=1.72, P=0.003), LIV cephalad to the SV(OR=2.31, P=0.007), pre-post CBD (OR=1.21, P=0.014) were identified as independent factors positively correlated with distal Adding-on phenomenon. The ROC curve revealed that the optimal cut-off point of LIV disc angle was 8.05°, the area under the ROC curve was 0.821, and the optimal cut-off point of pre-post CBD was 3.45cm, the area under the ROC curve was 0.915. Conclusions: Larger LIV disc angle， larger pre-post CBD, LIV cephalad to the SV are independent factors for postoperative adding-on in patients with congenital thoracic scoliosis undergoing posterior correction with long fusion.