骨盆代偿潜能对脊柱畸形经第2骶髂螺钉固定术后近端交界性后凸发生的影响

Effect of pelvic compensatory capacity on the occurrence of post-operative proximal junctional kyphosis in adult spinal deformity utilized second sacral alar-iliac screw

目的探讨经第2骶髂(second sacral alar iliac,S2AI)螺钉固定的成人脊柱畸形患者骨盆代偿潜能与术后发生近端交界性后凸(proximal junctional kyphosis,PJK)的相关性。方法回顾性分析2016年1月至2019年1月在南京医科大学鼓楼临床医学院骨科行后路经S2AI螺钉固定术的成人脊柱畸形患者55例,根据患者骨盆倾斜角(pelvic tilt,PT)与骨盆入射角(pelvic incidence,PI)比值,即骨盆倾斜比率(PT to PI ratio,PTr)的高低分为高PTr组(PT/PI>0.4)及低PTr组(PT/PI<0.4)。末次随访时按是否发生PJK分为PJK组与非PJK组。患者在术前、术后即刻及2年随访时摄站立位全脊柱正侧位X线片,测量并记录Cobb角、冠状面平衡(coronal balance distance,CBD)、最大后凸角(global kyphosis,GK)、胸椎后凸(thoracic kyphosis,TK)、腰椎前凸(lumbar lordosis,LL)、矢状面躯干偏移距离(sagittal vertical axis,SVA)、交界区后凸角(proximal junctional angle,PJA)、T1骨盆角(T1 pelvic angle,T1PA)、PI、PT、骶骨斜角(sacral slop,SS)及PI-LL。比较高PTr组与低PTr组在末次随访时PJK发生率的差异;同时比较PJK组与非PJK组末次随访时各影像学参数及术前、术后即刻、末次随访时PTr的差异,采用二分类变量logistic回归分析确定影响PJK发生的独立危险因素。结果低PTr组13例、高PTr组42例,末次随访时高PTr组患者术后PJK发生率[38%(16/42)]高于低PTr组[8%(1/13)],差异有统计学意义(P=0.035)。末次随访时17例患者发生PJK,logistic回归分析显示末次随访PJA[OR=1.274,95%CI(0.998,1.624),P=0.009]、术前PTr[OR=3.274,95%CI(1.100,36.973),P=0.035]及术后即刻PTr[OR=5.700,95%CI(1.271,65.272),P=0.029]为发生PJK的独立危险因素。结论高PTr患者的骨盆代偿能力较差,矫形术后骨盆代偿潜能仍偏低,随访期间难以维持良好的矢状面平衡,发生PJK的风险更高。

Objective To investigate the correlation between pelvic compensatory capacity and proximal junctional kyphosis(PJK)in patients with adult spinal deformity undergoing spino-pelvic fixation utilizing second sacral alar iliac(S2AI).Methods A cohort of 55 patients diagnosed with adult spinal deformity and treated with spino-pelvic fixation utilizing S2AI between January 2016 and January 2019 was included.The pelvic tilt to pelvic incidence ratio(PT to PI ratio,PTr)was used to categorize patients into high PTr group(PT/PI>0.4)and low PTr group(PT/PI<0.4).Subsequently,patients were further classified into PJK group and non-PJK group based on the occurrence of PJK during the last follow-up.Radiographic parameters such as Cobb angle,coronal balance distance(CBD),global kyphosis(GK),thoracic kyphosis(TK),lumbar lordosis(LL),sagittal vertical axis(SVA),proximal junctional angle(PJA),T1 pelvic angle(T1PA),pelvic incidence(PI),pelvic tilt(PT),sacral slope(SS),and PI-LL were measured preoperatively,postoperatively,and at final follow-up.The chi-square test was employed to compare the incidence of PJK between the high PTr and low PTr groups at the last follow-up.Additionally,multivariable logistic regression analysis was conducted to identify independent risk factors for PJK.Results The incidence of PJK was significantly higher in the high PTr group compared to the low PTr group[high PTr group(38%)vs.low PTr group(8%),P<0.05].Multivariable logistic regression analysis identified pre-operative PTr[OR=3.274,95%CI(1.100,36.973),P=0.035],post-operative PTr[OR=5.700,95%CI(1.271,65.272),P=0.029],and PJA at the last follow-up[OR=1.274,95%CI(0.998,1.624),P=0.009]as independent risk factors for PJK.Conclusion Patients with higher PTr exhibited poor pelvic compensatory ability,struggled to maintain optimal sagittal balance post-operation,and were at increased risk of developing PJK during follow-up.