退变性胸腰交界区后凸及其矢状位平衡代偿机制的影像学分析

Radiographic changes in degenerative thoracolumbar junctional kyphosis: sagittal balance and compensatory mechanism

目的 :对退变性胸腰交界区后凸及矢状面平衡进行影像学分析,探讨其代偿机制。方法 :将2016年3月~2017年5月影像学上表现为腰椎退变性后凸77例患者纳入本研究,其中男性30例,女性47例,年龄48~82岁,平均65.8±8.0岁。根据胸腰椎交界角(thoracolumbar junctional angle,TLJA)的大小将这些患者分为两组:退变性胸腰交界区后凸组(A组,TLJA≥10°,43例)和退变性胸腰交界区非后凸组(B组,TLJA<10°,34例)。通过对站立位脊柱全长正侧位X线片测量,对比分析两组的C7矢状面垂直轴(C7-sagittal vertical axis,C7-SVA)、胸椎后凸角(thoracic kyphosis,TK)、腰椎前凸角(lumbar lordosis,LL)、骨盆入射角(pelvic incidence,PI)、骶骨倾斜角(sacral slope,SS)和骨盆倾斜角(pelvic tilt,PT)。结果 :A组和B组的LL分别为17.30°±11.55°和22.54°±8.72°。A组及B组的TLJA分别为-15.26°±3.65°和-3.67°±4.74°。在A组中,LL与TK(r=-0.345,P=0.024),SS(r=0.595,P=0.000)以及PT(r=-0.363,P=0.017)均有相关性。在B组中,LL与TK(r=-0.400,P=0.019),SS(r=0.681,P=0.000)以及C7-SVA(r=-0.402,P=0.018)均有相关性。两组间,LL(t=2.230,P=0.029)、TK(t=3.325,P=0.001)、SS(t=2.939,P=0.004)和PI(t=2.130,P=0.036)均有统计学差异(P<0.05)。结论 :退变性胸腰交界区后凸可能是因胸腰交界区独特的形态学及生物力学特性所致,为了维持矢状位平衡,其骨盆后倾可能更加重要;不伴有退变性胸腰交界区后凸的患者,其胸椎曲度的改变可能更加重要。

Objectives： To compare the radiological parameters in patients with or without degenerative thoracolumbar junctional kyphosis（DTLJK）, and to analyze the compensatory mechanism of sagittal balance. Methods： From March 2016 to May 2017, 77 patients with degenerative lumbar kyphosis（sagittal imbalance due to lumbar kyphosis or marked loss of lumbar lordosis） were enrolled in our radiographic study, including 30 males and 47 females with an average age of 65.8±8.0 years（range, 48-82 years）. According to thoraeolumbar junctional angle （TLJA）, these patients were divided into two groups, degenerative thoracolumbar junctional kyphosis（DTLJK） group（group A, TLJA ≥10°, 43 patients） and non-degenerative thoracolumbar junctional kyphosis（NDTLJK） group（group B, TLJA〈10°, 34 patients）. Complete spino-pelvic radiographic parameters were compared between two groups, including C7-sagittal vertical axis, thoracic kyphosis, lumbar lordosis, pelvic incidence, pelvic tilt and sacral slope. Results： The lumbar lordosis of group A and B was 17.30°±11.55° and 22.54°±8.72°, respectively. The thoracolumbar junctional angle（TLJA） in patients of group A and B was - 15.26°±3.65° and -3.67°±4.74°, respectively. In group A, lumbar lordosis showed correlation with thoracic kyphosis（r=-0.345, P=0.024）, sacral slope（r=0.595, P=0.000） and pelvic tih（r=-0.363, P=0.017）. In group B, lumbar lordosis showed correlation with thoracic kyphosis（r=-0.400, P=0.019）, sacral slope（r=0.681, P=0.000） and C7-sagittal vertical axis（r=-0.402, P=0.018）. There were significant differences in lumbar lordosis（t=2.230, P=0.029）, thoracic kyphosis（t=3.325, P=0.001）, sacral slope（t=2.939, P=0.004） and pelvic incidence （t=2.130, P=0.036） between two groups. Conclusions： Degenerative thoracolumbar junctional kyphosis is common and may be generated from special characteristics of morphology and biomechanics of the thoracolumbar junction. To maintain sagittal balance, pelvis retroversion may be more important in patients with DTLJK, while thoracic curves changes may be more important in patients without DTLJK.