Department of Plastic Surgery, University Pittsburgh Medical Center, University of Pittsburgh, Pittsburgh, PA, USA.
First Settlement Orthopaedics, Marietta, OH, USA.
Clin Orthop Relat Res. 2024 Jan 1;482(1):134-140. doi: 10.1097/CORR.0000000000002751. Epub 2023 Jul 4.
Although idiopathic median neuropathy at the carpal tunnel (IMNCT) is objective and verifiable, distinction of normal and abnormal nerves is imprecise and probabilistic. The associated symptoms and signs (carpal tunnel syndrome [CTS]) vary, particularly for nonsevere (mild and moderate) median neuropathy. Discordance between diagnosis of mild or moderate median neuropathy at the carpal tunnel using symptoms and signs and diagnosis based on objective tests is a measure of the potential for overdiagnosis and overtreatment.
QUESTION/PURPOSE: What is the difference in the estimated prevalence of mild-to-moderate IMNCT using nonsevere signs and symptoms compared with the estimated prevalence using electrodiagnostic studies (EDS) and ultrasound (US)?
We used data from an existing cross-sectional data registry. To create this registry, between January 2014 and January 2019, we considered all new adult English-speaking people who had an EDS that included the median nerve or people with a diagnosis of CTS who did not have surgery yet. A small and unrecorded number of people declined participation. The cross-sectional area of the median nerve at the distal wrist crease using US in people who already had EDS was measured. People with a diagnosis of CTS underwent both EDS and US. The six signs and symptoms of Carpal Tunnel Syndrome 6 (CTS-6, a validated tool to estimate the probability of IMNCT using ratings of symptoms and signs of CTS) were recorded. This resulted in a registry of 185 participants; we excluded 75 people for obvious, severe IMNCT (defined as nonrecordable nerve conduction velocity, thenar atrophy, or greater than 5 mm 2-point discrimination). Three of the 110 qualifying patients had missing information on ethnicity or race, but we accounted for this in our final analysis. Without a reference standard, as is the case with IMNCT, latent class analysis (LCA) can be used to establish the probability that an individual has specific pathophysiologic findings. LCA is a statistical method that identifies sets of characteristics that tend to group together. This technique has been used, for example, in diagnosing true scaphoid fractures among suspected fractures based on a combination of demographic, injury, examination, and radiologic variables. The prevalence of mild-to-moderate IMNCT was estimated in two LCAs using four signs and symptoms characteristic of mild-to-moderate IMNCT, as well as EDS and US measures of median neuropathy.
The estimated prevalence of mild-to-moderate IMNCT based on signs and symptoms was 73% (95% CI 62% to 81%), while the estimated prevalence using EDS and US measurements was 51% (95% CI 37% to 65%).
The notable discordance of 22% between the estimated prevalence of mild-to-moderate IMNCT using signs and symptoms and prevalence based on EDS and US criteria, and the overlapping CIs of the probability estimations, indicate considerable uncertainty and a corresponding notable potential for underdiagnosis or overdiagnosis. When signs and symptoms suggest mild-to-moderate median neuropathy and surgery is being considered, patients and clinicians might consider additional testing, such as EDS or US, to increase the probability of actual median neuropathy that can benefit from surgery. We might benefit from a more accurate and reliable diagnostic strategy or tool for mild-to-moderate IMNCT; this might be the focus of a future study.
Level III, diagnostic study.
虽然特发性腕管正中神经病变（IMNCT）是客观且可验证的，但正常和异常神经的区分并不精确，且具有概率性。相关症状和体征（腕管综合征[CTS]）存在差异，尤其是对于非严重（轻度和中度）正中神经病变。使用症状和体征诊断腕管轻度或中度正中神经病变与基于客观测试的诊断之间的差异是过度诊断和过度治疗的衡量标准。
问题/目的：使用非严重体征和症状估计轻度至中度 IMNCT 的患病率与使用电诊断研究（EDS）和超声（US）估计的患病率有何不同？
我们使用现有横断面数据登记处的数据。为了创建该登记处，在 2014 年 1 月至 2019 年 1 月期间，我们考虑了所有新的成年英语使用者，他们接受了包括正中神经的 EDS，或尚未接受手术但患有 CTS 诊断的人。一小部分未记录的人拒绝参与。已经进行了 EDS 的人，使用 US 测量远端腕横纹处正中神经的横截面积。患有 CTS 诊断的人同时接受 EDS 和 US 检查。记录了 6 项 CTS-6 症状（评估 CTS 症状和体征以估计 IMNCT 概率的有效工具）。这导致了 185 名参与者的登记处；我们排除了 75 名明显患有严重 IMNCT 的人（定义为无法记录的神经传导速度、鱼际肌萎缩或大于 5mm 2 点辨别力）。由于缺乏参考标准（如 IMNCT），潜类别分析（LCA）可用于确定个体具有特定病理生理发现的概率。LCA 是一种识别倾向于组合在一起的特征集的统计方法。例如，这种技术已用于在疑似骨折中基于人口统计学、损伤、检查和放射学变量来诊断真正的舟骨骨折。在两个 LCAs 中，根据四个特征性的轻度至中度 IMNCT 体征和症状以及正中神经 EDS 和 US 测量值，估计了轻度至中度 IMNCT 的患病率。
基于体征和症状的轻度至中度 IMNCT 的估计患病率为 73%（95%CI 62%至 81%），而基于 EDS 和 US 测量值的估计患病率为 51%（95%CI 37%至 65%）。
基于体征和症状的轻度至中度 IMNCT 的估计患病率与基于 EDS 和 US 标准的患病率之间相差 22%，概率估计的置信区间重叠，这表明存在相当大的不确定性和相应的显著过度诊断或漏诊的可能性。当体征和症状提示轻度至中度正中神经病变且正在考虑手术时，患者和临床医生可能会考虑进行额外的测试，如 EDS 或 US，以增加可以从手术中受益的实际正中神经病变的概率。我们可能需要一种更准确和可靠的轻度至中度 IMNCT 诊断策略或工具；这可能是未来研究的重点。
III 级，诊断研究。
