BACKGROUND Kyphotic deformity occurrence after cervical laminoplasty is not rare. Several studies have emphasized the development of postoperative kyphotic deformity (PKD) will impair the functional outcome of cervical laminoplasty. We established and validated a nomogram prediction model for kyphotic deformity after laminoplasty in cervical spondylotic myelopathy patients (CSM) without preoperative kyphotic alignment. METHODS Preoperative and 1-year postoperative data of 369 patients who underwent single-door cervical laminoplasty (SDCL) at the author's hospital between July 2010 and February 2018 were collected. Using the least absolute shrinkage and selection operator (LASSO) method, significant parameters were selected to develop a nomogram prediction model. The prognostic performance of the model was evaluated using concordance index (C-index) and calibration curve. The discriminatory ability of the prediction model was evaluated by the area under (receiver operating characteristic) curve (AUC). RESULTS Of the 369 patients, 31 developed PKD in 1 year after the surgery. Using the LASSO regression, six significant variables composed the final model: age, C2-7 sagittal vertical axis, C7 slope, C2-7 angle, flexion range of motion and operation level were selected. The AUC of the nomogram was 0.771. The C-index for the prediction nomogram was 0.771 (95 % CI: 0.672-0.870). The calibration curve also indicated good consistency. CONCLUSION A nomogram for predicting PKD after SDCL was established and validated. For patients evaluated by this model with predictive high risk of developing postoperative kyphosis, an alternative approach to the subaxial cervical spine such as anterior surgery should be considered.

中文翻译：

---

没有术前脊柱后凸对线的脊髓型颈椎病患者椎板成形术后脊柱后凸畸形预测的列线图

背景技术颈椎椎板成形术后发生后凸畸形的情况并不少见。一些研究强调术后后凸畸形（PKD）的发展会损害颈椎椎板成形术的功能结果。我们建立并验证了无术前脊柱后凸对线的脊髓型颈椎病患者（CSM）椎板成形术后后凸畸形的列线图预测模型。方法 收集2010年7月至2018年2月笔者所在医院369例行单门颈椎椎板成形术（SDCL）患者的术前及术后1年资料。使用最小绝对收缩和选择算子 (LASSO) 方法，选择重要参数来开发列线图预测模型。使用一致性指数（C-index）和校准曲线评估模型的预后性能。通过（接收器操作特性）曲线下面积（AUC）评估预测模型的判别能力。结果 369 例患者中，31 例在术后 1 年内发生 PKD。使用LASSO回归，选择6个重要变量组成最终模型：年龄、C2-7矢状纵轴、C7斜率、C2-7角度、屈曲运动范围和手术水平。列线图的 AUC 为 0.771。预测列线图的 C 指数为 0.771（95% CI：0.672-0.870）。校准曲线也显示出良好的一致性。结论 建立并验证了 SDCL 后预测 PKD 的列线图。