成人脊柱畸形矫形术后冠状位失平衡的相关危险因素分析

Coronal imbalance in adult spinal deformity after corrective surgery:a:n analysis on the risk factors

目的:探索成人脊柱畸形(adult spinal deformity,ASD)患者矫形术后冠状位失平衡(coronal imbalance,CIB)的危险因素.方法:前瞻性纳入了在解放军总医院单一中心诊疗的90例ASD患者,患者均行后路长节段固定融合矫形手术(固定椎体≥5),术后随访至少2年.根据患者术前C7铅垂线(C7 plumb line,C7PL)与侧凸方向的关系,将所有患者分为两组,A组为同向性脊柱-骨盆序列(C7PL与侧凸同向),B组则反之(C7PL与侧凸相悖).规定冠状位平衡距(coronal balance distance,CBD)(C7PL到S1中点的距离)超过30mm为CIB.直线相关分析探索L4、L5椎体倾斜度及主弯Cobb角与术后早期CBD的相关性.Kaplan-Meier曲线分析随访期间非CIB生存时间.多因素Cox风险比例回归分析随访中CIB的相关危险因素.结果:20例ASD患者术前发生CIB,发生率约为22.2%;术后早期27例出现CIB;末次随访时35例患者发生CIB,发生率增至38.9%,显著高于术前CIB发生率(P=0.015).A组患者,术前11例出现CIB,末次随访时为22例,CIB发生率增加显著(P=0.019);B组患者术前及末次随访时CIB发生率无差异.末次随访时,骨盆固定患者CIB发生率显著高于非骨盆固定患者(P<0.00l).Kaplan-Meier曲线显示骨盆固定及年龄超过60岁患者随访过程中非CIB生存时间显著缩短.多因素Cox风险比例回归分析结果显示年龄>60岁、骨盆固定及同向性脊柱-骨盆序列均为术后随访中CIB发生的危险因素.尽管术后早期CBD分别与L4、L5倾斜度、主弯Cobb角及三者矫正度显著相关(P<0.01),多因素直线回归分析结果显示只有术前L5倾斜度为术后CBD独立相关因素(r^(2)=0.295,P<0.001).结论:成人脊柱畸形伴同向性脊柱-骨盆序列,且矫形术中行骶髂固定的老年患者,术后随访中极可能出现CIB再发生.

Objectives:To investigate the risk factors resulting in coronal imbalance(CIB)in adult spinal de-formity(ASD)after correction surgery.Methods:A single-center prospective study including 90 ASD patients underwent long segment fusion(≥5 vertebras)surgeries was performed.According to the relationship between preoperative C7 plumb line(C7PL)and scoliosis direction,the patients were subdivided into Group A with consistent spino-pelvis alignment(C7PL located at the convex side)and group B(C7PL at the concave side).CIB was considered if the coronal balance distance(CBD),the distance between C7PL and the midpoint of S1>30mm.Pearson-correlation and stepwise multiple-regression analysis were used to investigate coronal radio-graphic parameters related to CBD early postoperatively.A Kaplan-Meier curve was used to analyze the sur-vival time in CIB-free patients during follow-up.Multivariate analysis via a Cox proportional hazards model was used to analyze the risk factors.Results:20 out of the 90 patients(22.2%)showed CIB preoperatively,and the number increased to 27 at the immediate post-operation,which was 35(38.9%)at the final follow-up,significantly higher than that before operation(P=0.015).In group A,11 patients showed CIB preoperatively,the number was 22 at the final follow-up,with a significant increase in the incidence of CIB(P-0.019);and in group B,there was no statistical difference in terms of incidence of CIB between preoperation and final follow-up.Comparing to those without pelvic fusion,patients with pelvic fixation had much higher incidence of CIB at the final follow-up(P<0.001).Kaplan-Meier curve demonstrated the survival time of CIB-free patients aged>60 years and with pelvic fixation was significantly shortened.Multivariate Cox risk proportional regression analysis revealed age>60 years,pelvic fixation,and consistent spino-pelvis alignment were the risk factors for CIB surgery.Although early postoperative CBD corelated significantly with L4 tilt,L5 tilt,major curve Cobb,and their corrections(P<0.01),multiple-regression analysis revealed only the preoperative L5 tilt was the independent influencing factor of postoperative CBD(r^(2)=0.295,P<0.001).Conclusions:Elderly ASD patients with consistent spino-pelvis alignment underwent thoracolumbar fusion surgery extending to pelvis may be at the greatest risk for CIB developing during follow-up.