后路短节段跨伤椎椎弓根螺钉固定治疗胸腰段爆裂骨折术后再发后凸的危险因素

目的: 探索后路短节段跨伤椎椎弓根螺钉固定治疗胸腰段爆裂骨折内固定物取出术后再发后凸的危险因素。方法: 回顾性分析北京大学第三医院2010年1月至2017年12月诊治的无神经功能损害的单节段胸腰段爆裂骨折患者的临床资料,共有144例患者纳入该研究。所有患者均采用跨伤椎椎弓根螺钉固定,其中男性74例,女性70例;平均年龄(39.1±13.2)岁。伤椎分布在T12(42例)、L1(72例)和L2(30例),骨折类型为A3(90例)、B1(25例)和B2(29例)。根据取出内固定物后末次随访矫正度丢失是否>5°,将患者分为再发后凸组和无再发后凸组,再发后凸组共纳入92例,无再发后凸组共纳入52例。利用SPSS 26.0软件进行单因素组间比较及Logistic回归分析。结果: 平均随访时间28(20~113)个月,分别于术前、术后3 d、术后12个月及末次随访对患者影像学指标进行测量并对比分析。伤椎前缘高度、局部后凸角、伤椎楔形角、Gardner畸形等指标术后较术前均有明显改善(P<0.05),但在术后1年随访时均有不同程度的丢失;伤椎前缘高度和伤椎楔形角不再因取钉发生变化,而局部后凸角和Gardner畸形在取钉术后仍出现后凸加重(P<0.05);伤椎上、下椎间盘高度随访过程中出现不同程度的塌陷。单因素分析可见,再发后凸组和无再发后凸组患者的性别、年龄(36.9岁 vs. 43.0岁)、上位椎间盘损伤与否、CT值(174 vs. 160)、术前节段后凸角(16.6° vs. 13.3°)、术前伤椎楔形角(16.7° vs. 13.6°)、术前Gardner畸形(19.1° vs. 15.2°)及术前椎体前缘的高度比(0.65 vs. 0.71)差异具有统计学意义(P<0.05)。Logistics回归分析提示,男性(OR: 2.88,95%CI:1.196~6.933)、上位椎间盘损伤(OR: 2.962,95%CI:1.062~8.258)及术前伤椎楔形角是短节段跨伤椎椎弓根螺钉固定治疗胸腰段爆裂骨折取出内固定物后再发后凸的危险因素(P<0.05)。结论: 胸腰段骨折患者经后路短节段跨伤椎内固定能取得满意的术后即刻效果,但随访过程中可能会发生一定程度的矫正角度丢失,男性、上位椎间盘损伤及术前伤椎楔形角是内固定物取出后再发后凸的危险因素。

Risk factors of recurrent kyphosis in thoracolumbar burst fracture patients treated by short segmental pedicle screw fixation

Objective: To analyze the risk factors of recurrent kyphosis after removal of short segmental pedicle screw fixation in patients with thoracolumbar burst fractures.Methods: Retrospective analysis was conducted of 144 cases of thoracolumbar burst fractures without neurological impairment treated in Peking University Third Hospital from January 2010 to December 2017. There were 74 males and 70 females, with an average age of (39.1±13.2) years. The distribution of the injured vertebrae was T12: 42, L1: 72 and L2: 30, with fracture types of A3: 90, B1: 25 and B2: 29. The patients were divided into two groups: Recurrent kyphosis group (n=92) and non-recurrent kyphosis group (n=52). SPSS 26.0 software was used for univariate analysis and Logistic regression analysis.Results: The average follow-up time was 28 (20-113) months. The imaging indexes of pre-operation, 3 days post-operation, 12 months post-operation and the last follow-up were measured and compared. Anterior vertebral body height, segmental kyphosis, vertebral wadge angle and Gardner deformity were significantly improved after operation (P<0.05), and there were some degrees of loss in the 1-year follow-up; anterior vertebral body height and vertebral wadge angle were no longer changed after the removal of the screws; however, segmental kyphosis and Gardner deformity were still aggravated after the removal of the screws (P<0.05). There were some degrees of collapse of the height of the upper and lower discs during the follow-up. Univariate analysis showed that there were statistically significant differences (P<0.05) between the two groups in gender, age (36.9 years vs. 43.0 years), upper disc injury, CT value (174 vs. 160), segmental kyphosis (16.6° vs. 13.3°), vertebral wadge angle (16.7° vs. 13.6°), Gardner deformity (19.1° vs. 15.2°) and ratio of anterior vertebral body height (0.65 vs. 0.71). Logistic regression analysis showed that male (OR: 2.88, 95%CI: 1.196-6.933), upper disc injury (OR: 2.962, 95%CI: 1.062-8.258) and injured vertebral wedge angle were risk factors of recurrent kyphosis after removal of internal fixation for thoracolumbar burst fracture (P<0.05).Conclusion: The patients with thoracolumbar burst fracture can obtain satisfactory effect immediately after posterior short segmental pedicle screw fixation, however, there may be some degree of loss during the follow-up. Male, upper disc injury and injured vertebral wedge angle are the risk factors of recurrent kyphosis after removal of internal fixation for thoracolumbar burst fracture.