颈椎后路术后颈椎前凸曲度严重丢失临床预测模型的建立和验证

Establishment and validation of a clinical prediction model for severe loss of cervical lordosis after posterior cervical surgery

背景:目前的研究只是通过影像学测量指标及其他指标来预测颈椎术后前凸曲度丢失,汇总这些预测指标的相关文章尚少,此文旨在建立一个预测模型来汇总这些预测指标。目的:探讨脊髓型颈椎病后路手术后颈椎前凸曲度严重丢失的危险因素,并建立与验证预测模型。方法:回顾性分析2015年1月至2020年1月于徐州医科大学附属医院接受颈后路手术并符合纳入标准的脊髓型颈椎病患者。观察指标包括年龄、性别、体质量指数、手术方式选择、手术节段数、手术是否累及C_(2)或C_(7)、术前C_(2-7)Cobb角、手术节段Cobb角、C_(7)倾斜角、颈椎矢状面垂直距离、C_(2)-C_(7)曲率、伸展活动范围、屈曲活动范围,通过术前、术后颈椎C_(2-7)Cobb角差值确定颈椎术后前凸曲度变化(ΔCL),以ΔCL≤-10°为颈椎前凸曲度严重丢失组,ΔCL>-10°为无颈椎前凸曲度严重丢失组。对这些因素进行单因素和多因素分析,确定相关的危险因素,以建立预测模型并验证。结果与结论:(1)共有117例患者符合纳入标准,其中男69例,女48例,随访时间12-26个月;(2)在117例患者中,发现术后颈椎前凸严重丢失者30例,没有颈椎前凸曲度严重丢失者87例;(3)统计学分析显示:术式的选择、手术是否累及C_(2)或C_(7)椎体、术前C_(2-7)Cobb角、C_(7)倾斜角、C_(2)-C_(7)曲率、屈曲活动范围是导致颈后路手术后颈椎前凸曲度严重丢失的独立危险因素,其中增加术后曲度严重丢失风险最明显的是手术节段是否累及C_(2)或C_(7)节段(OR=3.524,95%CI:1.127-11.013)以及手术术式选择(OR=3.165,95%CI:1.013-9.889);(4)并进一步建立了临床预测模型(Nomogram)并进行验证,其内部验证C-index值为0.91,验证组进行外部验证C-index值为0.87,提示该模型具有较好的预测能力;(5)提示手术术式的选择、手术节段是否累及C_(2)或C_(7)节段、术前C_(2-7)Cobb角、C_(7)倾斜角、屈曲活动度是颈后路手术后颈椎前凸曲度严重丢失的高危因素。

BACKGROUND:Current studies only predict the loss of cervical lordosis after cervical surgery through imaging measurement indicators and other indicators at present.There are a few articles summarizing these prediction indicators.This paper establishes a prediction model to summarize these prediction indicators.OBJECTIVE:To investigate the risk variables for severe loss of cervical lordosis following posterior cervical spondylotic myelopathy surgery,as well as to develop and validate the prediction model.METHODS:Retrospective analysis was performed on the cervical spondylotic myelopathy patients who underwent posterior approach of cervical surgery in the Affiliated Hos pital of Xuzhou Medical University from January 2015 to January 2020 and met the inclusion criteria.The observation indexes included age,sex,body mass index,surgical technique chosen,the number of operation segments,accumulation of C_(2) or C_(7),C_(2-7) Cobb angle prior to operation,Cobb angle of ope ration segment,C_(7)slope angle,sagittal vertical angle of the cervical spine,C_(2)-C_(7)curvature,extension range of motion,and flexion range of motion.The difference between the cervical spine’s C_(2-7)Cobb angle before and after surgery(ΔCL)was used to calculate the change in cervical lo rdosis.Those withΔCL≤-10°had significant loss of cervical lordosis,while those with ΔCL>-10°had less severe loss of cervical lordosis.Prediction models were created and validated by doing single-factor and multi-factor analyses on these parameters to identify pertinent risk factors.RESULTS AND CONCLUSION:117 patients in all,48 females and 69 males,met the inclusion crite ria.The follow-up ti me ranged from 12 to 26 months.Among these patients,30 expe rienced a severe loss of cervical lo rdosis following surge ry,while 87 patients did not have a severe loss of cervical lo rdosis.Statistical analysis showed that the choice of procedure,whether it involved the C_(2)or C_(7)vertebral bodies,the C_(2-7) Cobb angle,the C_(7)slope angle,the C_(2)-C_(7)curvature,and flexion range of motion prior to the procedure were independent risk factors linked to serious loss of cervical lordosis following poste rior cervical surgery.Most obviously,whether the surgical segment involved the C_(2)or C_(7)segment(OR=3.524,95%CI:1.127-11.013),and the surgical approach chosen(OR=3.165,95%CI:1.013-9.889)were the factors that enhanced the probability of significant postoperative curvature loss.Further foundations were laid for the clinical prediction model(nomogram)and its validation.The model has an excellent capacity for prediction,as evidenced by the C-index of internal validation,which was 0.91,and the C-index of external validation in the validation group,which was 0.87.It is indicated that after poste rior cervical surgery,the choice of operation method,whether the operation segment involves the C_(2)or C_(7)segment,the preoperative C_(2-7)Cobb angle,the C_(7)slope angle,and flexion mobility all are high risks of severe oss of cervical lordosis.