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: an analysis on the risk factors

中文关键词:  成人脊柱畸形  冠状位失平衡  冠状位平衡距  Kaplan-Meier曲线

英文关键词:Adult spinal deformity  Coronal imbalance  Coronal balance distance  Kaplan-Meier analysis

中文摘要:

  【摘要】 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<0.001）。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（r2=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。

英文摘要:

  【Abstract】 Objectives: To investigate the risk factors resulting in coronal imbalance(CIB) in adult spinal deformity(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 radiographic parameters related to CBD early postoperatively. A Kaplan-Meier curve was used to analyze the survival 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(r2=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.