成人脊柱畸形后路固定融合手术前后冠状面失平衡的相关性分析

Coronal imbalance in adult spinal deformity following posterior spinal fusion with instrument: a related parameter analysis

目的探索成人脊柱畸形(adult spinal deformity,ASD)患者手术前、后冠状面失衡情况及相关因素,明确术前参数及手术因素是否对术后即刻冠状面失衡造成影响。方法回顾性分析67例长节段固定融合手术(≥4椎体)ASD患者的手术前、后的影像学资料,记录截骨处、截骨级别及融合节段,在站立位脊柱全长正、侧位X线片上测量影像学参数,冠状面:侧凸Cobb’s角度、侧凸类型(左或右)、侧凸顶椎旋转度、顶椎位置、C7铅垂线(C7 plumb line,C7PL)到骶骨中分线(central sacral vertical line,CSVL)的距离即冠状面平衡差距(coronal balance distance,CBD);侧凸纠正(dCobb=术前Cobb-术后Cobb);顶椎旋转纠正(d顶椎旋转=术前顶椎旋转度-术后顶椎旋转度);矢状面:胸椎后凸角(thoracic kyphosis,TK)、胸腰段后凸角(thoracic lumber kyphosis,TLK)、腰椎前凸角(lumber lordosis,LL)、骶骨角(sacral slope,SS)、骨盆倾斜角(pelvic tilt,PT)、骨盆入射角(pelvic incidence,PI)、矢状面平衡(sagittal vertical axis,SVA),手术前、后相应参数做配对t检验。post-CBD与其它参数做相关回归分析。根据患者术前侧凸类型及CBD分为A组(-30.00 mm<CBD<30.00 mm)、B组(CBD>30.00 mm或CBD<-30.00 mm,C7PL位于侧凸凹侧)及C组(CBD>30.00 mm或CBD<-30.00 mm,C7PL位于侧凸凸侧)三组,F检验分析三组相关参数,χ2检验比较手术前、后冠状面失衡比,三组患者性别比及相关手术参数。结果本组67例手术前、后侧凸Cobb’s角[(-8.85±24.56)°vs.(-2.99±9.53)°]、顶椎旋转度[(2.1±0.99)°vs.(0.91±0.6)°]、TK[(17.25±12.80)°vs.(21.87±9.73)°]、TLK[(20.31±15.31)°vs.(9.98±7.64)°]、LL[(22.74±19.78)°vs.(39.13±12.05)°]、SS[(22.58±12.82)°vs.(30.63±10.63)°]、PT[(24.27±11.25)°vs.(16.22±9.04)°]、SVA[(48.58±52.03)mm vs.(13.29±38.37)mm],差异均有统计学意义(P<0.05);PI、CBD差异无统计学意义(P>0.05)。所有患者手术前、后冠状面失衡率分别为31.34%(21/67)和40.30%(27/67),术后冠状面失衡比例较术前明显增加,差异有统计学意义(χ2=5.31,P=0.02)。多重相关回归分析结果显示,post-CBD与dCobb、pre-CBD密切相关(r=0.569,P=0.00;r=0.649,P=0.002),得出回归方程,post-CBD=-2.737-0.924×dCobb+0.356×pre-CBD。A、B、C组患者术后冠状面失衡分别为16/51、5/9、6/7,C组患者术后冠状面失衡率明显高于其它两组(χ2=8.561,P=0.01)。结论后路长节段固定融合术可以有效改善ASD患者脊柱序列;患者胸段及骨盆存在自我调节能力;术后CBD与冠状面侧凸矫正及术前CBD密切相关;术前存在冠状面失衡且C7PL位于侧凸凸侧患者术后更易出现冠状面失衡。

Objective To explore radiological parameters correlated to post-operation coronal imbalance,and to investigate whether pre-operation coronal imbalance affects post-operation coronal imbalance following posterior spinal fusion with instrument and osteotomy operation.Methods The study included 67 patients(13 males and 54 females)with ASD who underwent posterior long-segment spinal fixation(at least 4 vertebrae)and osteotomy.The age ranged from 45 to 79 years(mean:63.93±8.46 years).Medical records of 67 ASD patients were reviewed.Radiological parameters of the spine were measured on the pre-and post-operation anteroposterior and lateral radiographs.Coronal plane:curve Cobb’s angle,type of curve(left or right),degree of apical vertebra rotation,location of apical vertebra/disc,coronal balance distance(CBD;the distance between C7PL and CSVL),modified degree of the curve(pre-Cobb-post-Cobb),modified degree of the apical vertebra rotation(pre-rotation degree-post-rotation degree).Sagittal plane:thoracic kyphosis(TK),thoracolumbar kyphosis(TLK),lumbar lordosis(LL),sacral slope(SS),pelvic tilt(PT),pelvic incidence(PI),sagittal vertical axis(SVA).Pre-and post-operational radiological parameters were compared by paired samples t-test respectively.Relations between post-CBD and other radiological parameters were analyzed by linear-regression test.All patients were divided into three groups according to the type of the curves and the pre-CBD.A:-30.00 mm<CBD<30.00 mm;B:CBD>30.00 mm or CBD<-30.00 mm,and C7PL shifted to the concave side of the curve;C:CBD>30.00 mm or CBD<-30.00 mm,and C7PL shifted to the convex side of the curve.Radiological parameters of the 3 groups were analyzed by F test.The ratios of gender,curve type,pre-and post-operational coronal imbalance were compared byχ2-tset.Results Results of paired samples t-test showed that differences of radiological parameters pre-and post-operation were significant(P<0.05):curve Cobb’s angles[(-8.85±24.56)°vs.(-2.99±9.53)°],degree of apical vertebra rotation[(2.1±0.99)°vs.(0.91±0.6)°],TK[(17.25±12.80)°vs.(21.87±9.73)°],TLK[(20.31±15.31)°vs.(9.98±7.64)°],LL[(22.74±19.78)°vs.(39.13±12.05)°],SS[(22.58±12.82)°vs.(30.63±10.63)°],PT[(24.27±11.25)°vs.(16.22±9.04)°],SVA[(48.58±52.03)mm vs.(13.29±38.37)mm].The PI,pre-and post-CBD showed no significant differences(P>0.05).The ratio of coronal imbalance pre-and post-operation was 31.34%(21/67)and 40.30%(27/67)respectively with significant differences(χ2=5.31,P=0.02).There were significant correlations among post-CBD,pre-CBD,and dCobb(r=0.569,P=0.00;r=0.649,P=0.002).Post-CBD=-2.737-0.924×dCobb+0.356×pre-CBD.The ratios of coronal imbalance of Group A,B and C were 16/51;5/9;6/7 respectively,and Group C was significantly higher than the other two groups(χ2=8.561,P=0.01).Conclusions Sagittal alignments in ASD patients will be improved significantly after posterior spinal fusion with instrument and osteotomy operation.Parameters of TK and pelvis will adapt themselves to be in line with those of modified segments.There are significant correlations among post-CBD,pre-CBD,and the modified degree of the coronal curve.Patients of Group C may be at greater risk for postoperation coronal imbalance following posterior spinal fusion with instrument and osteotomy operation.