Nottingham University Hospitals NHS Trust Ringgold standard institution, Spinal Unit, Nottingham, UK.
Aga Khan University Hospital, Karachi, Pakistan.
Bone Joint J. 2020 Jun;102-B(6):677-682. doi: 10.1302/0301-620X.102B6.BJJ-2020-0195.R1.
Diagnosis of cauda equina syndrome (CES) remains difficult; clinical assessment has low accuracy in reliably predicting MRI compression of the cauda equina (CE). This prospective study tests the usefulness of ultrasound bladder scans as an adjunct for diagnosing CES.
A total of 260 patients with suspected CES were referred to a tertiary spinal unit over a 16-month period. All were assessed by Board-eligible spinal surgeons and had transabdominal ultrasound bladder scans for pre- and post-voiding residual (PVR) volume measurements before lumbosacral MRI.
The study confirms the low predictive value of 'red flag' symptoms and signs. Of note 'bilateral sciatica' had a sensitivity of 32.4%, and a positive predictive value (PPV) of only 17.2%, and negative predictive value (NPV) 88.3%. Use of a PVR volume of ≥ 200 ml was a demonstrably more accurate test for predicting cauda equina compression on subsequent MRI (p < 0.001). The PVR sensitivity was 94.1%, specificity 66.8%, PPV 29.9% and NPV 98.7%. The PVR allowed risk-stratification with 13% patients deemed 'low-risk' of CES. They had non-urgent MRI scans. None of the latter scans showed any cauda equina compression (p < 0.006) or individuals developed subsequent CES in the intervening period. There were considerable cost-savings associated with the above strategy.
This is the largest reported prospective evaluation of suspected CES. Use of the PVR volume ≥ 200 ml was considerably more accurate in predicting CES. It is a useful adjunct to conventional clinical assessment and allows risk-stratification in managing suspected CES. If adopted widely it is less likely incomplete CES would be missed. Cite this article: 2020;102-B(6):677-682.
马尾综合征 (CES) 的诊断仍然困难；临床评估在可靠预测马尾受压的准确性较低。本前瞻性研究测试超声膀胱扫描作为诊断 CES 的辅助手段的有用性。
在 16 个月的时间里，共有 260 名疑似 CES 的患者被转介到三级脊柱科。所有患者均由有资质的脊柱外科医生进行评估，并在腰骶部 MRI 检查前和排空后进行经腹超声膀胱扫描，以测量残余尿量 (PVR)。
本研究证实了“红旗”症状和体征的低预测价值。值得注意的是，双侧坐骨神经痛的敏感性为 32.4%，阳性预测值（PPV）仅为 17.2%，阴性预测值（NPV）为 88.3%。残余尿量 (PVR) ≥ 200ml 是预测后续 MRI 中马尾受压的更准确的试验（p<0.001）。PVR 的敏感性为 94.1%，特异性为 66.8%，PPV 为 29.9%，NPV 为 98.7%。PVR 可进行风险分层，其中 13%的 CES 低危患者。他们进行了非紧急 MRI 扫描。在这之后的检查中没有一个显示有马尾受压（p<0.006），也没有一个人在随访期间出现 CES。上述策略与相当大的成本节约相关。
这是目前报道的最大规模的 CES 疑似病例前瞻性评估。使用 PVR 体积≥200ml 对 CES 的预测准确性更高。它是传统临床评估的有用辅助手段，并允许在管理疑似 CES 时进行风险分层。如果广泛采用，不太可能会遗漏不完整的 CES。引用本文：2020;102-B(6):677-682。
