Demura Satoru, Murakami Hideki, Kato Satoshi, Yoshioka Katsuhito, Yonezawa Noritaka, Takahashi Naoki, Tsuchiya Hiroyuki
Department of Orthopaedic Surgery, Kanazawa University, Japan.
Spine Surg Relat Res. 2017 Dec 20;1(1):27-30. doi: 10.22603/ssrr.1.2016-0006. eCollection 2017.
Currently, excellent three-dimensional correction can be achieved with use of segmental pedicle screw fixation in adolescent idiopathic scoliosis (AIS). In the majority of patients with major thoracic curves, selective thoracic fusion (STF) may be considered to maximize motion segment of the unfused lumbar spine. This study aimed to investigate the extent of spontaneous derotation of the lumbar curve following STF.
AIS patients who underwent STF using posterior pedicle screw fixation were retrospectively reviewed. Angle of vertebral rotation was defined as the difference between the axial rotation angles of the apical vertebra and S1 vertebra on axial CT images. Radiographic measurements included major thoracic curve, thoracolumbar/lumbar curve (preoperative and postoperative), and side-bending curve. The relationships between the axial rotation of the lumbar spine and radiographic measurements were also analyzed.
Thirty patients (all females) were included. Preoperative thoracic Cobb measured 62.1±9°, which improved to 20.3±5° at 2 years postoperatively, resulting in 67% correction. Preoperative lumbar Cobb measured 38.0±9°, which spontaneously improved to 19.0±7°, indicating a 50% correction. Preoperatively, the axial rotation of apical lumbar vertebra was 10.2±5.5°, which changed to 7.0±4.8° (32% spontaneous correction). Comparing the correction between the axial rotation of the lumbar spine and other parameters, postoperative angle of axial rotation correlated well with preoperative (r=0.79) and postoperative (r=0.82) lumbar Cobb angle. Meanwhile, the improvement of axial rotation of the lumbar spine correlated with postoperative thoracic curve (r=－0.42), postoperative lumbar curve (r=－0.57), and thoracic apical translation change (r=0.43).
In AIS patients with major thoracic curves, spontaneous axial derotation of the lumbar curves occurred with a mean correction rate of 32% after STF. A greater spontaneous derotation of the lumbar curve would be related to correction of the thoracic curve.
目前，在青少年特发性脊柱侧凸（AIS）中使用节段性椎弓根螺钉固定可实现出色的三维矫正。在大多数主要为胸弯的患者中，可考虑进行选择性胸椎融合（STF）以最大化未融合腰椎的活动节段。本研究旨在调查STF后腰椎侧凸的自发旋转程度。
对采用后路椎弓根螺钉固定进行STF的AIS患者进行回顾性研究。椎体旋转角度定义为轴向CT图像上顶椎和S1椎体的轴向旋转角度之差。影像学测量包括主要胸弯、胸腰段/腰段侧凸（术前和术后）以及侧弯。还分析了腰椎轴向旋转与影像学测量之间的关系。
纳入30例患者（均为女性）。术前胸椎Cobb角为62.1±9°，术后2年改善至20.3±5°，矫正率达67%。术前腰椎Cobb角为38.0±9°，自发改善至19.0±7°，矫正率为50%。术前，腰椎顶椎的轴向旋转为10.2±5.5°，变为7.0±4.8°（自发矫正32%）。比较腰椎轴向旋转与其他参数的矫正情况，术后轴向旋转角度与术前（r = 0.79）和术后（r = 0.82）腰椎Cobb角相关性良好。同时，腰椎轴向旋转的改善与术后胸弯（r = -0.42）、术后腰弯（r = -0.57）以及胸椎顶椎平移变化（r = 0.43）相关。
在主要为胸弯的AIS患者中，STF后腰椎曲线出现自发轴向旋转，平均矫正率为32%。腰椎曲线更大的自发旋转与胸弯的矫正有关。
