成人脊柱畸形术前冠状面失平衡及其与脊柱-骨盆影像学参数的关系

Relation analysis between coronal imbalance and spine-pelvic parameters in adult spinal deformity

目的:测量成人脊柱畸形(adult spinal deformity,ASD)患者术前脊柱-骨盆参数,探讨ASD患者术前脊柱-骨盆参数与冠状面失衡的相关性。方法:回顾分析161例ASD患者的术前影像学资料,在站立位脊柱全长正、侧位X线片上测量影像学参数,冠状位参数包括主弯角度(Cobb角)、代偿弯角度(compensatory angle,CCobb角)、侧凸方向(左或右)、侧凸累及椎体数(vertebra number,VN)、侧凸椎体半脱位程度(subluxation degree,SD)、侧凸顶椎旋转度(apex rotation,AR)、顶椎位置、C7铅垂线(C7PL)到S1中点的距离(coronal balance distance,CBD);矢状位参数包括胸椎后凸角(TK)、胸腰段后凸角(TLK)、腰椎前凸角(LL)、骶骨角(SS)、骨盆倾斜角(PT)、骨盆入射角(PI)、矢状面平衡(SVA)。将患者分为失衡组(CBD>30.00mm,A组)和平衡组(CBD<30.00mm,B组),χ2检验比较两组患者比例参数,t检验比较两组影像学参数。结果:161例ASD患者的年龄为45～79岁(63.9±8.4岁),男女比为29∶132(M∶F),侧凸方向106∶55(左∶右),冠状面失衡组31例(男8例,女23例),平衡组130例(男21例,女109例),总失衡率为19.25%(31/161)。侧凸顶椎大多处于L2～L3节段,约占75.16%(121/161)。失衡组和平衡组患者年龄、性别比、左右侧凸比例、TK、TLK、LL、SS、PT、PI及SVA均无显著性差异(P>0.05),两组侧凸顶椎位置有显著性差异(χ2=12.692,P<0.001),失衡组顶椎位置均处于L2～L3节段;两组患者主弯及代偿弯Cobb角均无显著性差异(P>0.05),但失衡组患者NV少于平衡组(3.87±0.85vs 4.36±0.95;t=2.639,P=0.009);失衡组患者AR大于平衡组(2.81±0.60 vs 2.32±0.77;t=-3.796,P<0.001),TLK大于平衡组(t=-2.445,P=0.017)。将顶椎处于L2～L3节段的121例患者分为失衡组(CBD>30.00mm,A′组,31例)和平衡组(CBD<30.00mm,B′组,90例),两组主弯Cobb角、C-Cobb角无显著性差异(P>0.05);A′组患者主弯累及椎体数明显少于B′组(3.87±0.85 vs 4.23±0.85;t=2.052,P=0.04);A′组患者AR明显大于B′组(2.81±0.60 vs 2.27±0.68;t=-3.905,P<0.001)。结论:约1/5的ASD患者术前冠状面失平衡,且侧凸顶椎均位于L2～L3节段;侧凸角度相似、顶椎旋转度较大、侧凸累及椎体数目较少的患者更易出现冠状位失平衡。

Objectives： To explore the prevalence of coronal imbalance, and to demonstrate the relationship between coronal imbalance and spine-pelvic parameters by investigating the pre-operative radiographic param- eters in adult spinal deformity （ASD）. Methods： A total of 161 patients with ASD in our hospital was reviewed. The radiographic parameters were measured on the pre-operative anteroposterior and lateral spinal ra- diographs. Parameters on coronal plane included curve angle（Cobb）, compensatory angle（C-Cobb）, types of curvature（left or right）, the involved vertebrae and the subluxation degree of structural curvature, the degree of apical vertebra rotation（AR）, coronal pelvic tilt angle（C-PT）, coronal balance distance（CBD）： the coronal offset between C7PL and the center of S1 endplate. Parameters on sagittal plane included thoracic kyphosis （TK）, thoraeolumbar kyphosis（TLK）, lumbar lordosis（LL）, sacral slope（SS）, pelvic tih（PT）, pelvic incidence（PI）, sagittal vertical axis（SVA）. Patients were divided into two groups, group A（the imbalance group, CBD〉30.00mm） and group B （CBD〈30.00mm）. Radiographic parameters in imbalance and balance group were compared by using independent samples t-test. The ratio of gender, and the types of curve in the two groups were compared by using χ^2-tset. Results： All the 161 patients were included in this study, 29 males（M） and 132 females（F）, with the age ranging from 45 to 79 years（63.9±8.4 years）. Among them, 106 patients had left side curve, and the other 55 patients had right side curve. Coronal imbalance occurred in 31 patients（M：F, 8：23）, but did not occure in the other 130 patients（M：F, 21：109）. The coronal imbalance rate was 19.25%（31/161）. The age, gen- der, types of curve, TK, TLK, LL, SS, PT, PI and SYA in the two groups had no significant differences（P〉 0.05）. The location of apical vertebra had significant difference between the two groups（χ^2=12.692, P〈0.001）, the apical vertebrae were all located at L2 to L3 segments. Although the Cobb degree of the structural and the compensatory curvature in the two groups had no difference respectively （P〉0.05）, the involved vertebrae were less in group A than those in group B（3.87±0.85 vs 4.36±0.95, t=2.639, P=0.009）, and the degree of apical vertebra rotation in group A was much more than that in group B （2.81±0.60 vs 2.32±0.77, t=-3.796, P〈0.001）. The thoracolumbar kyphosis degrees in group A were much bigger than those in group B（t=-2.445, P=0.017）. The 121 patients whose apical vertebra located at L2 to L3 segment were divided into two groups, group A′（the imbalance group, CBD〉30.00mm） including 31 patients and group B′（CBD〈30.00mm） including 90 patients. The curve angle（Cobb）, the compensatory angle（C-Cobb）, the involved vertebrae and the subluxation degree of structural curvature, and the degree of apical vertebra rotation （AR） of the two groups were compared by using independent samples t-test respectively. The similar results were found： although the Cobb degree of the structural and the compensatory curvature had no significant difference respectively（P〉0.05）, the involved vertebrae were less in group A′ than those in group B′（3.87±0.85 vs 4.23±0.85, t=2.052, P=0.04）, and the degree of apical vertebra rotation in group A′ was much more than that in group B′（2.81±0.60 vs 2.27±-0.68, t=-3.905, P〈0.001） . Conclusions： The prevalence of pre-operative coronal imbalance in ASD patients is about 20%. The apical vertebrae of the structural curvatures locate at L2 to L3 segments. The patients who have more rotation degrees, less involved vertebrae, may more easily suffer from coronal imbalance.