Study Design: 

Retrospective, single-center case study.

Objective: 

Postoperative cervical imbalance with cervical sagittal vertical axis (cSVA) >4 cm can be predicted in 3-level to 5-level anterior-only cervical multilevel fusion surgery (ACMS).

Summary of Background Data: 

Previous studies established correlations between cervical kyphosis (CK) correction and postoperative balance (cSVA ≤4 cm) with improved clinical outcomes. Understanding of what influences restoration of cervical lordosis (CL) in patients with degenerative disease with mild to moderate CK subjected to ACMS is important. To achieve a better understanding of geometric changes after ACMS, this study examines factors predicting perioperative alignment changes and regional interdependencies.

Materials and Methods: 

Analysis of patients with ACMS. Analysis included patient baseline characteristics, demographics and complications, and focused on radiographic measures including CL C2-7, fusion angle (FA), C7-Slope (C7S), T1-slope (T1S), T1-CL mismatch, and cSVA (cSVA ≤4 cm/>4 cm). We aimed to predict postoperative imbalance (cSVA >4 cm) and conducted a multivariable logistic regression analysis.

Results: 

Inclusion of 126 patients with 3-level to 5-level ACMS, mean age was 56 years and 4 fusion levels on average. Preoperative CK was present in 9%, mean FA-correction was 8 degrees, maximum 46 degrees. Postoperatively, 14 patients had cSVA >4 cm. A neural network model for prediction of cSVA >4 cm was established including preoperative cSVA, preoperative CL and correction of FA. The model achieved high performance (positive predictive value=100%, negative predictive value=94%, specificity=100%, sensitivity=20%). Also, variables such as nonunion, chronic lumbar pain or thoracolumbar multilevel fusion influenced the postoperative cSVA >4 cm rate. Alignment analysis highlighted strong correlations between C7S/T1S and cSVA/C2-tilt (r=0.06/r=0.7, P<0.0001). A formula was established to transfer cSVA data into C2-tilt data.

Conclusion: 

This study identified independent variables predicting postoperative cSVA >4 cm including FA, which can be influenced by the surgeon. Our model supports the decision-making process targeting a postoperative cSVA ≤4 cm.

中文翻译：

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使用笼子和钢板进行前路多级减压后的 3 级至 5 级退行性融合手术调整：从几何变化分析、相互耦合和矢状颈椎平衡预测中汲取的经验教训

学习规划： 

回顾性、单中心案例研究。

客观的： 

在 3 节至 5 节前路颈椎多节段融合手术 (ACMS) 中，可以预测术后颈椎不平衡，颈椎矢状垂直轴 (cSVA) >4 cm。

背景数据摘要： 

先前的研究建立了颈椎后凸 (CK) 矫正和术后平衡 (cSVA ≤ 4 cm) 之间的相关性，并改善了临床结果。了解影响轻度至中度 CK 接受 ACMS 的退行性疾病患者颈椎前凸 (CL) 恢复的因素非常重要。为了更好地了解 ACMS 后的几何变化，本研究检查了预测围手术期对齐变化和区域相互依赖性的因素。

材料和方法： 

ACMS 患者分析。分析包括患者基线特征、人口统计学和并发症，并重点关注影像学测量，包括 CL C2-7、融合角 (FA)、C7 斜率 (C7S)、T1 斜率 (T1S)、T1-CL 不匹配和 cSVA (cSVA) ≤4厘米/>4厘米）。我们旨在预测术后失衡（cSVA > 4 cm）并进行了多变量逻辑回归分析。

结果： 

纳入 126 例 3 级至 5 级 ACMS 患者，平均年龄 56 岁，平均 4 级融合。术前 CK 存在率为 9%，平均 FA 校正为 8 度，最大 46 度。术后，14 例患者 cSVA >4 cm。建立了预测cSVA>4 cm的神经网络模型，包括术前cSVA、术前CL和FA校正。该模型取得了较高的性能（阳性预测值=100%，阴性预测值=94%，特异性=100%，敏感性=20%）。此外，骨不连、慢性腰痛或胸腰椎多节段融合等变量也会影响术后 cSVA >4 cm 的发生率。比对分析强调了 C7S/T1S 和 cSVA/C2-tilt 之间的强相关性 ( r =0.06/ r =0.7, P <0.0001)。建立了将cSVA数据转换为C2倾斜数据的公式。

结论： 

这项研究确定了预测术后 cSVA >4 cm（包括 FA）的自变量，该变量可能受到外科医生的影响。我们的模型支持针对术后 cSVA ≤4 cm 的决策过程。