Department of Spinal Surgery, Peking University People's Hospital, Beijing 100044, China.
Chin Med J (Engl). 2017 Nov 5;130(21):2535-2540. doi: 10.4103/0366-6999.217090.
Thoracolumbar junction (TLJ) is the transitional area between the lower thoracic spine and the upper lumbar spine. Vertebral compression fractures and proximal junctional kyphosis following spine surgery often occur in this area. Therefore, the study of development and mechanisms of thoracolumbar junctional degeneration is important for planning surgical management. This study aimed to review radiological parameters of thoracolumbar junctional degenerative kyphosis (TLJDK) in patients with lumbar degenerative kyphosis and to analyze compensatory mechanisms of sagittal balance.
From January 2016 to March 2017, patients with lumbar degenerative kyphosis were enrolled in this radiographic study. Patients were divided into two groups according to thoracolumbar junctional angle (TLJA): the non-TLJDK (NTLJDK) group (TLJA <10°) and the TLJDK group (TLJA ≥10°). Complete spinopelvic radiographic parameters were analyzed and compared between two groups. Pearson or Spearman correlation coefficients and independent two-sample t-test or Mann-Whitney U-test were used.
A total of 77 patients with symptomatic sagittal imbalance due to lumbar degenerative kyphosis were enrolled in this study. There were 34 patients in NTLJDK group (TLJA <10°) and 43 patients in TLJDK group (TLJA ≥10°). The median angle of lumbar lordosis (LL) in the NTLJDK or TLJDK groups was 23.40° (18.50°, 29.48°) or 19.50° (13.30°, 24.55°), respectively. The median TLJAs in all patients and both groups were -11.20° (-14.60°, -4.80°), -3.70° (-7.53°, -1.73°), and -14.30° (-17.45°, -13.00°), respectively. In the NTLJDK group, LL was correlated with thoracic kyphosis (TK; r = -0.400, P = 0.019), sacral slope (SS; r = 0.681, P < 0.001), and C7-sagittal vertical axis (r = -0.402, P = 0.018). In the TLJDK group, LL was correlated with TK (r = -0.345, P = 0.024), SS (r = 0.595, P < 0.001), and pelvic tilt (r = -0.363, P = 0.017). There were significant differences in LL, TLJA, TK, SS, and pelvic incidence (PI) between two groups.
Although TLJDK is common in patients with lumbar degenerative kyphosis, it might be generated by special characteristics of morphology and biomechanics of the TLJ. To maintain sagittal balance, pelvis back tilt might be more important in patients with TLJDK, whereas thoracic curve changes might be more important in patients without TLJDK.
胸腰椎连接部（TLJ）是下胸椎和上腰椎之间的过渡区域。脊柱手术后，椎体压缩性骨折和近端连接部后凸经常发生在这个区域。因此，研究胸腰椎连接部退行性变的发展和机制对于规划手术管理非常重要。本研究旨在回顾腰椎退行性变患者的胸腰椎连接部退行性变后凸（TLJDK）的放射学参数，并分析矢状平衡的代偿机制。
从 2016 年 1 月至 2017 年 3 月，这项放射学研究纳入了腰椎退行性变患者。根据胸腰椎连接部角（TLJA）将患者分为两组：非 TLJDK（NTLJDK）组（TLJA < 10°）和 TLJDK 组（TLJA ≥ 10°）。分析并比较两组之间的完整脊柱骨盆放射学参数。使用 Pearson 或 Spearman 相关系数以及独立两样本 t 检验或 Mann-Whitney U 检验。
本研究共纳入了 77 例因腰椎退行性变导致有症状的矢状不平衡患者。NTLJDK 组（TLJA < 10°）有 34 例，TLJDK 组（TLJA ≥ 10°）有 43 例。NTLJDK 或 TLJDK 组的腰椎前凸角（LL）中位数分别为 23.40°（18.50°，29.48°）或 19.50°（13.30°，24.55°）。所有患者和两组的 TLJA 中位数分别为-11.20°（-14.60°，-4.80°）、-3.70°（-7.53°，-1.73°）和-14.30°（-17.45°，-13.00°）。在 NTLJDK 组中，LL 与胸曲（TK；r = -0.400，P = 0.019）、骶骨倾斜角（SS；r = 0.681，P < 0.001）和 C7-矢状垂直轴（r = -0.402，P = 0.018）呈负相关。在 TLJDK 组中，LL 与 TK（r = -0.345，P = 0.024）、SS（r = 0.595，P < 0.001）和骨盆倾斜角（r = -0.363，P = 0.017）呈负相关。两组间的 LL、TLJA、TK、SS 和骨盆入射角（PI）存在显著差异。
尽管 TLJDK 在腰椎退行性变患者中很常见，但它可能是由 TLJ 的形态和生物力学的特殊特征引起的。为了维持矢状平衡，在 TLJDK 患者中，骨盆后倾可能更为重要，而在无 TLJDK 的患者中，胸椎曲度的变化可能更为重要。
