退变性腰椎侧凸后路长节段固定融合术后近端交界性后凸的危险因素分析

Risk factors analysis of proximal junctional kyphosis following posterior long instrumented spinal fusion for degenerative lumbar scoliosis

中文关键词:  近端交界性后凸  危险因素  发生率  退变性腰椎侧凸

英文关键词:Proximal junctional kyphosis  Risk factor  Incidence  Degenerative lumbar scoliosis

中文摘要:

  【摘要】 目的：探讨退变性腰椎侧凸（degenerative lumbar scoliosis，DLS）后路长节段固定融合术后发生近端交界性后凸（proximal junctional kyphosis，PJK）的危险因素。方法：回顾性分析2009年4月~2014年5月于我院行长节段（≥5个椎体）固定融合手术、年龄≥45岁、随访时间≥2年的DLS患者共60例。将随访时出现PJK的患者纳入PJK组，其余患者纳入对照组。用单变量分析比较两组患者个体资料、手术资料和影像学参数间的差异，找出潜在的危险因素，然后用Logistic回归分析确定独立危险因素。个体资料包括性别、年龄、体重指数（BMI）、骨密度（BMD）和T-值。手术资料包括固定融合椎体数、最上端固定椎（UIV）位置、最下端固定椎（UIV）位置、截骨操作和椎间融合。影像学参数包括侧凸Cobb角、胸椎后凸角（TK）、胸腰段后凸角（TLK）、腰椎前凸角（LL）、骨盆入射角（PI）、骨盆倾斜角（PT）、骶骨倾斜角（SS）、总矢状位序列（GSA）、矢状位平衡（SVA）和交界区后凸角（PJA1为UIV+1上终板与UIV下终板的夹角；PJA2为UIV+2上终板与UIV下终板的夹角）等。结果：研究共纳入DLS患者60例，年龄63.2±6.4岁（45~74岁），术前Cobb角28.51°±10.94°（10.7°~55.1°），手术平均固定融合节段6.7±1.3个（5~9个）。随访40.3±11.1个月（24～59个月），末次随访时11例患者发生PJK（PJK组），49例患者未发生PJK（对照组），PJK发生率为18.3%。与对照组相比，PJK组有更多的BMD<0.850g/cm2例数（100.0% vs 36.1%, P=0.005）；更多的UIV位于T11-L1例数（100.0% vs 69.4%，P=0.030）；更多的术前PJA1>9°例数（45.5% vs 10.2%，P=0.013）、术前TLK≥15°例数（63.6% vs 22.4%，P=0.012）、术前SS＜25°例数（90.9% vs 46.9%，P=0.016）、术后即刻PJA2≥5°例数（100.0% vs 46.9%，P=0.001）和术后即刻PJA2增长≥3°例数（90.9% vs 46.9%，P=0.016）。Logistic回归分析示术前PJA1＞9°（OR=19.432，P=0.017）、术前SS<25°（OR=23.131，P=0.022）和术后即刻PJA2增长≥3°（OR=22.382，P=0.025）为发生PJK的独立危险因素。结论：术前PJA1＞9°、术前SS<25°和术后即刻PJA2增大≥3°是发生PJK的独立危险因素，BMD<0.850g/cm2、UIV位于T11-L1、术前TLK≥15°和术后即刻PJA2≥5°是发生PJK的潜在危险因素。

英文摘要:

  【Abstract】 Objectives: To investigate the risk factors of proximal junctional kyphosis(PJK) following posterior long instrumented spinal fusion in degenerative lumbar scoliosis(DLS) patients. Methods: This retrospective review included 60 DLS patients who underwent one stage posterior long instrumented spinal fusion in our spinal center from April 2009 to May 2014. The inclusion criteria included: (1) age not less than 45 years; (2) at least five fusion vertebrae; (3) at least 2-year follow-up. All patients followed up 40.3±11.1 months(24-59 months). According to the occurrence of PJK at final follow-up, patients were divided into two groups: PJK group and control group. The differences of patient data, surgical data and radiographic parameters between the two groups were analyzed by univariate analysis and the potential risk factors were identified. Logistic regression analysis was used to find the independent risk factors. Patient data included preoperative data of sex, age, body mass index(BMI), bone mineral density(BMD) and T-score. Surgical data included the number of instrumented and fused vertebrae, upper instumented vertebra(UIV) level, lowest instumented vertebra(LIV) level, osteotomy and interbody fusion. Radiographic parameters included scoliosis Cobb angle, thoracic kyphosis (TK), thoracolumbar kyphosis(TLK), lumbar lordosis(LL), pelvic incidence(PI), pelvic tilt(PT), sacral slope(SS), global sagittal alignment(GSA), sagittal vertical axis(SVA) and proximal junctional angle(PJA1, the angle between the end plate of UIV+1 and the end plate of the UIV; PJA2, the angle between the end plate of UIV+2 and the end plate of the UIV). Results: The 60 DLS patients(45-74, 63.2±6.4 years) showed an average preoperative Cobb angle of 28.51°±10.94°(10.7°-55.1°), the mean number of instrumented levels was 6.7±1.3(5-9). PJK was developed in 11 of 60 patients(18.3%) until final follow-up, who were enrolled as the PJK group, and 49 patients without PJK at final follow-up were enrolled as the control group. There were statistically significant differences between the two groups in number of cases with BMD<0.850g/cm2(100.0% in the PJK group and 36.1% in the control group, P=0.005), number of UIV at T11-L1 patients(100.0% in the PJK group and 69.4% in the control group, P=0.030), number of preoperative PJA1>9° patients(45.5% in the PJK group and 10.2% in the control group, P=0.013), number of preoperative TLK≥15° patients(63.6% in the PJK group and 22.4% in the control group, P=0.012), number of preoperative SS＜25° patients(90.9% in the PJK group and 46.9% in the control group, P=0.016), number of immediate postoperative PJA2≥5° patients(100.0% in the PJK group and 46.9% in the control group, P=0.001) and number of immediate postoperative PJA2 increase ≥3° patients(90.9% in the PJK group and 46.9% in the control group, P=0.016). When included in a multivariate logistic regression model, preoperative PJA1>9°(OR=19.432, P=0.017), preoperative SS＜25°(OR=23.131, P=0.022) and immediate postoperative PJA2 increase≥3°(OR=22.382, P=0.025) were independent risk factors for PJK. Conclusions: Preoperative PJA1>9°, preoperative SS＜25° and immediate postoperative PJA2 increase ≥3° are identified as independent risk factors for PJK. BMD<0.850g/cm2, UIV at T11-L1, preoperative TLK≥15° and immediate postoperative PJA2≥5° are potential risk factors for PJK.