特发性胸椎侧凸前路矫形对胸主动脉偏移的影响及意义

目的 比较青少年特发性胸椎右侧凸患者前路开放小切口矫形手术和后路矫形手术对胸主动脉偏移的影响及其意义.方法 29例青少年特发性胸椎右侧凸患者分为两组.A组14例患者行开放小切口前路矫形术,男1例,女13例,平均14.3岁,胸弯Cobb角平均44.9°.B组15例患者行后路钉钩联合矫形术,男3例,女12例,平均14.2岁,胸弯Cobb角平均46.4°.两组患者手术前后均行胸椎T5～T12节段CT扫描,在每个节段测量右侧肋骨头至主动脉后壁的切线与双侧肋骨头连线的夹角(α)、椎管前缘中点与主动脉中心连线和双侧肋骨头连线的夹角(β)、椎体旋转(γ)、主动脉与椎体间距离(a)以及与左侧肋骨头前缘的垂直距离(b)并进行比较.将胸主动脉偏移与侧凸的三维矫形进行相关性分析明确胸主动脉偏移的原因.结果 A组患者手术后置钉安全角α、主动脉相对椎管前缘旋转角β较术前增大,在T8,T9差异有显著性(P＜0.05);椎体旋转γ角减小,在T8,T9差异有显著性(P＜0.05);主动脉与椎体间距离a减小,主动脉后壁与右侧肋骨头间距离b增大,两者和术前相比在T9有显著性差异(P＜0.05).B组手术前后椎体旋转及主动脉与相邻椎体的解剖关系无明显变化.A组α角、β角、b值增加量与γ角减小量呈明显相关性(P＜0.01);a值减少量与β角增加量具有良好相关性(P＜0.05);在顶椎区α角、β角、b值的增加量与顶椎偏移减少量、a值减少量与T5～T12后凸增加量明显相关(P＜0.01).结论 特发性胸椎右侧凸患者行小切口前路矫形术后胸主动脉相对椎体向前方偏移并靠近椎体.发生主动脉偏移的原因包括主动脉松解、椎体去旋转、冠状面和矢状面矫形.

Thoracic scoliosis following anterior and posterior instrumentation and fusion

OBJECTIVES: To quantify the changes of the spatial relations between the vertebral body and the thoracic aorta in main right thoracic adolescent idiopathic scoliosis (AIS) following anterior and posterior instrumentation and fusion. METHODS: Twenty-nine patients with main right thoracic AIS were divided into 2 groups. Group A included 13 females and 1 male with an average age of 14.3 years old and average main thoracic Cobb angle of 44.9 degrees, these patients underwent mini-incision thoracotomic anterior spinal fusion. Group B included 12 females and 3 males with an average age of 14.2 years old and average main thoracic Cobb angle of 46.4 degrees, all of them were treated with posterior spinal fusion. Patients underwent CT scanning from T5 to T12 Pre-and post-operatively. Five parameters pertaining to the spatial relations between the vertebral body and the thoracic aorta including the angle for safety screw placement (gamma), the angle of the aorta relative to the vertebral body (beta), vertebral rotation angle (gamma), distance from the aorta to the closest point of the vertebral body cortex (a) and distance from the posterior wall of the aorta to the anterior edge of the left rib head (b) were analyzed and were correlated with the curve correction. RESULTS: In Group A, the alpha angle and 3 angle increased while gamma decreased after curve correction, and significant difference were found at T8 and T9 levels (P < 0.05); the a value decreased and b value increased after curve correction and reached significant difference at T9 (P < 0.05). No significant change of these parameters was found in Group B post-operatively. In Group A, the increment of alpha angle, beta angle and b value show great correlation with the decrement of gamma angle (P < 0.01). At the periapical the increment of alpha angle, beta angle and b value show great correlation with decrement of apical vertebral translation, while decrement of a value show great correlation with increment of kyphosis from T5 to T12 (P < 0.01). CONCLUSIONS: Under anterior instrumentation and correction, the aorta moved anteromedially toward vertebral body on CT scanning. The factors contributing to the aorta shifting included releasing of aorta from vertebrae, vertebral derotation and curve correction.