Vaughn Joshua J, Schwend Richard M
Children's Mercy Hospital, Kansas City, MO.
J Pediatr Orthop. 2014 Mar;34(2):202-7. doi: 10.1097/BPO.0000000000000075.
Several variables can have effect on sagittal balance. The changes that occur between standing and sitting have been inadequately studied, especially in the, pediatric population.
Preoperative sagittal radiographs were obtained in both standing and sitting positions for 26 patients with idiopathic scoliosis before spinal fusion and instrumentation. Standard measurements of thoracic kyphosis, lumbar lordosis, sacral slope (SS), pelvic incidence, pelvic tilt, and lumbar intervertebral angles were, recorded. Differences were compared between positions using 2-sided paired t tests.
When moving from standing to a seated position, the spine loses 5-degree thoracic kyphosis (P=0.007), 29-degree lumbar lordosis (P<0.0001), and the sacrum rotates 20 degrees (P<0.0001) to a more vertical position. The greatest change in sitting sagittal balance occurs due to increased pelvic tilt with decreased SS. The next greatest change is increased forward flexion of the lowest 2 lumbar vertebrae, 6.5 degrees between L4-L5 (P<0.0001) and 5.9 degrees between L5-S1 (P<0.0001). Flexion occurs throughout the lumbar spine but its magnitude decreases in the more proximal lumbar segments, 1.6 degrees between L1-L2 (P=0.028). The sagittal vertical axis also moves more anterior by 44 mm (P<0.0001).
Sitting significantly straightens the spine with decreases of thoracic kyphosis, lumbar lordosis, and SS. The majority of the changes occur in the lumbar spine and pelvis. As humans spend much of their time sitting, this difference should be considered when spinal instrumentation is performed. These findings may be important to those who only sit, especially when instrumentation is extended to the pelvis.
Level II--retrospective prognostic study.
多个变量可影响矢状面平衡。站立位与坐位之间发生的变化尚未得到充分研究，尤其是在儿科人群中。
对26例特发性脊柱侧凸患者在脊柱融合及内固定术前分别获取站立位和坐位的矢状面X线片。记录胸椎后凸、腰椎前凸、骶骨倾斜度（SS）、骨盆入射角、骨盆倾斜度和腰椎椎间角度的标准测量值。采用双侧配对t检验比较不同体位之间的差异。
从站立位转变为坐位时，脊柱的胸椎后凸减少5度（P = 0.007），腰椎前凸减少29度（P < 0.0001），骶骨旋转20度（P < 0.0001）至更垂直的位置。坐位矢状面平衡的最大变化是由于骨盆倾斜增加和SS减小。第二大变化是最低的2节腰椎向前屈曲增加，L4 - L5之间增加6.5度（P < 0.0001），L5 - S1之间增加5.9度（P < 0.0001）。腰椎全长均出现屈曲，但在更靠近头端的腰段屈曲幅度减小，L1 - L2之间为1.6度（P = 0.028）。矢状垂直轴也向前移动44 mm（P < 0.0001）。
坐位时脊柱明显变直，胸椎后凸、腰椎前凸和SS减小。大部分变化发生在腰椎和骨盆。由于人类大部分时间处于坐位，在进行脊柱内固定时应考虑这种差异。这些发现对于仅处于坐位的人群可能很重要，尤其是当内固定延伸至骨盆时。
II级——回顾性预后研究。
