MacDowall Anna, Skeppholm Martin, Robinson Yohan, Olerud Claes
1Department of Surgical Sciences, Uppsala University Hospital, Uppsala; and.
2Department for Learning, Informatics, Management and Ethics, Karolinska Institutet, Stockholm, Sweden.
J Neurosurg Spine. 2018 Mar;28(3):227-235. doi: 10.3171/2017.5.SPINE1732. Epub 2017 Dec 15.
OBJECTIVE The visual analog scale (VAS) is frequently used to measure treatment outcome in patients with cervical spine disorders. The minimum clinically important difference (MCID) is the smallest change in a score that has clinical importance to the patient. Although it has been established for other medical fields, knowledge of the VAS MCID for the cervical spine is sparse, and it has rarely been considered in relation to measurement noise. The goals in this study were as follows: 1) to validate the VAS-neck and VAS-arm instruments for the cervical spine (e.g., repeatability); 2) to investigate the possible influence of predictive factors and the Hospital Anxiety and Depression Scale (HADS) score on repeatability; and 3) to compute the MCID with 5 different methods. METHODS A post hoc analysis of a prospective randomized controlled trial with 151 patients undergoing surgery for cervical radiculopathy due to degenerative disc disease was performed. Information on age, sex, smoking habits, exercise, employment status, HADS score, and VAS-neck and VAS-arm scores was gathered before surgery and after 1 year. The VAS was applied twice on every occasion, with 15 minutes in between. Repeatability and the association with predictors and HADS score were analyzed using the 1-sample t-test, linear regression models, and Spearman correlation. The MCID was calculated with the following methods: average change, change difference, receiver operating characteristic curve, effect size, and minimum detectable change (MDC). RESULTS The repeatability in VAS-neck was 8.1 mm, and in VAS-arm it was 10.4 mm. Less consistent values on the VAS correlated to female sex and higher values on the HADS. For VAS-neck the MCID ranged from 4.6 to 21.4, and for VAS-arm it ranged from 1.1 to 29.1. The highest MCID came from the MDC method, which was the only method that gave values above the measurement noise in both VAS-neck and VAS-arm. CONCLUSIONS Measurement noise in VAS-neck and VAS-arm for the cervical spine was influenced by female sex and HADS score. The only method to compute MCID that consistently gave results above the measurement noise in VAS-neck and VAS-arm was the MDC. Clinical trial registration no.: 44347115 ( www.isrctn.com ).
目的 视觉模拟评分法（VAS）常用于评估颈椎病患者的治疗效果。最小临床重要差异（MCID）是指对患者具有临床意义的评分最小变化值。尽管MCID在其他医学领域已得到确立，但关于颈椎病VAS的MCID的了解却很少，而且很少有人将其与测量噪声联系起来考虑。本研究的目标如下：1）验证用于颈椎病的VAS颈部评分和VAS手臂评分工具（如重复性）；2）研究预测因素和医院焦虑抑郁量表（HADS）评分对重复性的可能影响；3）用5种不同方法计算MCID。方法 对一项前瞻性随机对照试验进行事后分析，该试验纳入了151例因退行性椎间盘疾病接受颈椎神经根病手术的患者。收集患者术前及术后1年的年龄、性别、吸烟习惯、运动情况、就业状况、HADS评分以及VAS颈部评分和VAS手臂评分信息。每次应用VAS评分两次，间隔15分钟。使用单样本t检验、线性回归模型和Spearman相关性分析重复性以及与预测因素和HADS评分的关联。用以下方法计算MCID：平均变化值、变化差值、受试者工作特征曲线、效应量和最小可检测变化值（MDC）。结果 VAS颈部评分的重复性为8.1mm，VAS手臂评分的重复性为10.4mm。VAS评分一致性较差的值与女性性别以及HADS评分较高相关。VAS颈部评分的MCID范围为4.6至21.4，VAS手臂评分的MCID范围为1.1至29.1。最高的MCID来自MDC方法，这是唯一在VAS颈部评分和VAS手臂评分中均给出高于测量噪声值的方法。结论 VAS颈部评分和VAS手臂评分的测量噪声受女性性别和HADS评分影响。在VAS颈部评分和VAS手臂评分中始终给出高于测量噪声结果的计算MCID的唯一方法是MDC。临床试验注册号：44347115（www.isrctn.com）
