Department of Orthopaedic Surgery, Asklepios Klinikum Uckermark, Schwedt/Oder, Germany.
Spine (Phila Pa 1976). 2010 Apr 15;35(8):892-7. doi: 10.1097/BRS.0b013e3181c7cf4b.
Retrospective case-referent study.
To assess whether the new sedimentation sign discriminates between nonspecific low back pain (LBP) and symptomatic lumbar spinal stenosis (LSS).
In the diagnosis of LSS, radiologic findings do not always correlate with clinical symptoms, and additional diagnostic signs are needed. In patients without LSS, we observe the sedimentation of lumbar nerve roots to the dorsal part of the dural sac on supine magnetic resonance image scans. In patients with symptomatic and morphologic central LSS, this sedimentation is rarely seen. We named this phenomenon "sedimentation sign" and defined the absence of sedimenting nerve roots as positive sedimentation sign for the diagnosis of LSS.
This study included 200 patients. Patients in the LSS group (n = 100) showed claudication with or without LBP and leg pain, a cross-sectional area <80 mm, and a walking distance <200 m; patients in the LBP group (n = 100) had LBP, no leg pain, no claudication, a cross-sectional area of the dural sac >120 mm, and a walking distance >1000 m. The frequency of a positive sedimentation sign was compared between the 2 groups, and intraobserver and interobserver reliability were assessed in a random subsample (n = 20).
A positive sedimentation sign was identified in 94 patients in the LSS group (94%; 95% confidence interval, 90%-99%) but none in the LBP group (0%; 95% confidence interval, 0%-4%). Reliability was kappa = 1.0 (intraobserver) and kappa = 0.93 (interobserver), respectively. There was no difference in the detection of the sign between segmental levels L1-L5 in the LSS group.
A positive sedimentation sign exclusively and reliably occurs in patients with LSS, suggesting its usefulness in clinical practice. Future accuracy studies will address its sensitivity and specificity. If they confirm the sign's high specificity, a positive sedimentation sign can rule in LSS, and, with a high sensitivity, a negative sedimentation sign can rule out LSS.
回顾性病例对照研究。
评估新的沉降征是否能区分非特异性下腰痛（LBP）和症状性腰椎管狭窄症（LSS）。
在 LSS 的诊断中，影像学发现并不总是与临床症状相关，需要额外的诊断标志。在没有 LSS 的患者中，我们观察到腰椎神经根在仰卧位磁共振图像扫描时向硬脊膜背侧沉降。在有症状和形态学中央型 LSS 的患者中，这种沉降很少见。我们将这种现象命名为“沉降征”，并将无沉降神经根定义为 LSS 诊断的阳性沉降征。
本研究纳入了 200 例患者。LSS 组（n=100）患者表现为跛行伴或不伴 LBP 和腿部疼痛，横截面积<80mm，行走距离<200m；LBP 组（n=100）患者有 LBP，无腿部疼痛，无跛行，硬脊膜横截面积>120mm，行走距离>1000m。比较两组之间阳性沉降征的频率，并在随机亚样本（n=20）中评估观察者内和观察者间的可靠性。
LSS 组 94 例（94%；95%置信区间，90%-99%）患者存在阳性沉降征，而 LBP 组均无阳性沉降征（0%；95%置信区间，0%-4%）。可靠性分别为kappa=1.0（观察者内）和 kappa=0.93（观察者间）。LSS 组各节段 L1-L5 水平的征象检出率无差异。
阳性沉降征仅且可靠地发生在 LSS 患者中，提示其在临床实践中的有用性。未来的准确性研究将关注其敏感性和特异性。如果它们证实该征象具有高特异性，阳性沉降征可用于诊断 LSS，而阴性沉降征具有高敏感性时则可排除 LSS。
