Department of Neurology and Neurophysiology, University Medical Center Freiburg, Freiburg, Germany.
Department of Neurology, University Medical Center Basel, Basel, Switzerland.
Pain Pract. 2021 Mar;21(3):308-315. doi: 10.1111/papr.12960. Epub 2020 Oct 31.
The tourniquet ischemia test (IT) is a hitherto rarely used tool for the diagnostic work-up of patients with suspected complex regional pain syndrome (CRPS). This analysis aims to determine the sensitivity and specificity of this test, and elucidate factors that can influence the test result.
Consecutive data on clinical presentation, results of the IT and other diagnostic tests, and clinical characteristics were analyzed from patients presenting at our autonomic laboratory between 2000 and 2011. IT results were compared with the final clinical diagnosis at discharge, and statistical analysis was performed to determine specificity, sensitivity, and positive and negative predictive values of the IT.
A total of 78 patients were assessed. IT results were positive (≥50% reduction in pain during ischemia) in 26 cases and negative in 52 cases. CRPS was the final diagnosis in 45 cases, and in 33 cases, a different diagnosis was made. This results in a test sensitivity of 49% and a specificity of 88%, with a positive predictive value of 85% and a negative predictive value of 56%. Age, sex, the type and stage of CRPS, and the affected extremity did not influence the test result in a statistically significant manner. Specificity worsened to 76% if any pain reduction was rated as a positive test result.
A positive tourniquet IT has a high positive predictive value for the diagnosis of CRPS. It is thus useful as a confirmatory assay in patients with suspected CRPS. Low sensitivity rules out its use as a screening test.
This study retrospectively analyzed the clinical significance of the tourniquet IT that was routinely used in patients with suspected CRPS. It showed that a positive IT result is useful as a confirmatory assay in patients fulfilling the clinical criteria.
止血带缺血试验（IT）是一种迄今很少用于疑似复杂性区域疼痛综合征（CRPS）患者诊断的工具。本分析旨在确定该试验的灵敏度和特异性，并阐明可能影响试验结果的因素。
分析了 2000 年至 2011 年间在我们的自主实验室就诊的患者的临床表现、IT 结果和其他诊断测试以及临床特征的连续数据。将 IT 结果与出院时的最终临床诊断进行比较，并进行统计分析以确定 IT 的特异性、灵敏度、阳性和阴性预测值。
共评估了 78 例患者。26 例 IT 结果阳性（缺血期间疼痛减少≥50%），52 例 IT 结果阴性。CRPS 是最终诊断的 45 例，33 例患者做出了不同的诊断。因此，该试验的灵敏度为 49%，特异性为 88%，阳性预测值为 85%，阴性预测值为 56%。年龄、性别、CRPS 的类型和阶段以及受影响的肢体并未以统计学显著的方式影响试验结果。如果任何疼痛减轻被评定为阳性试验结果，则特异性会恶化至 76%。
阳性止血带 IT 对 CRPS 的诊断具有较高的阳性预测值。因此，它可作为疑似 CRPS 患者的确认性检测。低灵敏度排除了其作为筛选测试的用途。
本研究回顾性分析了常规用于疑似 CRPS 患者的止血带 IT 的临床意义。结果表明，阳性 IT 结果对符合临床标准的患者具有作为确认性检测的作用。
