退变性脊柱侧凸患者后路矫形术后腰椎前凸指数对矢状面平衡的预测作用

Prediction of lumbar lordosis index on post-operative sagittal balance during follow-up in degenerative scoliosis

中文关键词:  退变性脊柱侧凸  腰椎前凸指数  失平衡  矢状面参数

英文关键词:Degenerative scoliosis  Lumbar lordosis index  Sagittal imbalance  Sagittal alignment

中文摘要:

  【摘要】 目的：探讨术后腰椎前凸指数（lumbar lordosis index，LLI）对退变性脊柱侧凸患者后路矫形术后矢状面平衡的预测作用。方法：回顾性分析2005年1月~2011年12月在我院行单一后路矫形术的57例退变性脊柱侧凸患者，其中男9例，女48例，年龄56.3±10.8岁（48~70岁）。纳入标准为年龄45岁以上、内固定节段≥5个节段且随访≥2年的患者。在术前、术后即刻和末次随访的站立位全脊柱X线片上测量矢状面垂直轴（SVA）、胸椎后凸角（TK）、腰椎前凸角（LL）、骨盆入射角（PI）、骨盆倾斜角（PT）和骶骨倾斜角（SS），计算腰椎前凸指数（LLI=LL/PI）。根据末次随访时患者矢状面平衡情况分为正常组（A组，末次随访时SVA≤5cm且PT≤25°）和失代偿组（B组，末次随访时SVA>5cm或PT>25°）。应用相关性分析研究57例患者术前、术后即刻和末次随访时LLI与其他脊柱骨盆矢状面参数的相关性，使用独立样本t检验分别比较A组和B组患者术前、术后即刻和末次随访的矢状面参数，P<0.05为差异有统计学意义。结果：A组患者41例，B组16例。术后随访时间4.4±1.9年（2~8年），其中A组随访4.3±1.8年，B组随访4.6±1.9年，两组随访时间无统计学差异（P=0.725）。57例患者LLI与相应时间点的PI、LL、PT、SVA和LL丢失值均有显著相关性（P<0.05），但与TK和SS无相关性。两组间术前LLI的差异无统计学意义（0.45±0.18 vs. 0.47±0.21，P=0.638）；A组术后即刻LLI为0.89±0.13，显著大于B组术后即刻的LLI（0.61±0.14）（P=0.005）。A组末次随访时SVA为2.73±2.62cm、PT为20.34°±4.28°，而B组患者末次随访时SVA为7.81±3.26cm、PT为29.81±5.13°，两组间SVA和PT的差异均有统计学意义（P<0.01）。结论：术后即刻LLI重建不良的退变性脊柱侧凸患者在随访中可能出现矢状面失代偿的风险，而良好的术后LLI重建可以降低随访中脊柱矢状面失平衡的风险。

英文摘要:

  【Abstract】 Objectives: To evaluate the role of post-operative lumbar lordosis index(LLI) in predicting the sagittal balance in degenerative scoliosis by comparing the LLI in patients with or without sagittal balance during follow-up. Methods: This was a retrospective review on 57 patients with degenerative scoliosis who underwent one stage posterior surgical instrumentation in our spinal center from January 2005 to December 2011. The inclusion criteria included: (1) age more than 45 years; (2) follow-up more than 2 years; (3) more than 5 fusion levels. The following sagittal spino-pelvic parameters were measured: sagittal vertical axis(SVA), thoracic kyphosis(TK), lumbar lordosis(LL), pelvic incidence(PI), pelvic tilt(PT) and sacral slope(SS). Lumbar lordosis index(LLI) was also assessed as the formula: LLI=LL/PI. Based on sagittal alignment at the last follow-up, patients were divided into two groups: group A(SVA≤5cm and PT≤25°, 41 cases) and group B(SVA>5cm or PT>25°, 16 cases). Correlation was researched among radiographic parameters at each time point. Independent t test was performed for statistical analysis. For all statistical analyses, the level of significance was set at P<0.05. Results: The mean follow-up averaged 4.4±1.9 years(range: 2-8 years). No significant difference was observed regarding the follow-up time between group A and B(4.3±1.8 years for group A and 4.6±1.9 years for group B, P=0.752). Significant correlations of LLI were found with PI, LL, PT, SVA, loss of LL at the corresponding time point(all P<0.05). No correlation between TK and SS was observed. Preoperative LLI did not differ significantly between group A and B(0.45±0.18 vs. 0.47±0.21, P=0.638). Postoperative LLI was 0.89±0.13 in group A, significantly larger than that in group B(0.89±0.13 vs. 0.61±0.14, P=0.005). SVA in group A was 2.73±2.62cm at the last follow-up, significantly smaller than that in group B(2.73±2.62cm vs. 7.81±3.26cm, P<0.01). PT at the last follow-up averaged 20.34°±4.28° and 29.81°±5.13° respectively in group A and B. Conclusions: Failure to restore LLI can predispose sagittal malalignment during follow-up in patients with degenerative scoliosis. Well-restored LLI may reduce the risk of postoperative sagittal imbalance during follow-up.