Joaquim Andrei Fernandes, Baum Griffin, Tan Lee A, Riew K Daniel
Neurosurgery Division, Department of Neurology, State University of Campinas (UNICAMP), Campinas, Brazil.
Department of Orthopedic Surgery, Columbia University, New York, NY, USA.
Neurospine. 2019 Jul 24. doi: 10.14245/ns.1938202.101.
The diagnosis of cervical spondylotic myelopathy (CSM) is made based on clinical signs and symptoms, and then confirmed with magnetic resonance imaging (MRI) or CT myelogram. Due to the highly mobile nature of the cervical spine, and the fact that most MRIs and CTs are obtained only in one single position, dynamic cord compression can be an elusive diagnosis that is often missed and not well-understood. In this context, dynamic MRI (dMRI) has been utilized to improve the diagnostic accuracy of cervical stenosis in cases where static MRI does not provide enough information to establish a diagnosis or to provide additional information. We performed a literature review on dynamic cord compression in the context of CSM, with particular emphasis on the role of dynamic MRI (dMRI). Cadaveric studies report that the spinal cord lengthens in flexion and the spinal canal dimension increases, whereas the spinal cord relaxes and shortens in extension and the spinal canal decreases. These changes may lead to biomechanical stress in the spinal cord with movement, especially in patients with critical cervical stenosis. The majority of the studies using dMRI in CSM reported that this imaging modality is more sensitive at detecting cervical cord compression compared to routine MRIs done in a neutral position, especially with the neck in extension. Occult anterior compression has also been reported by some authors in flexion, but occurs less frequently. DMRI was also useful to diagnose dynamic cervical cord compression after laminectomies in patients with clinical deterioration without evident cord compression on neutral static MRI. Finally, dMRI are more sensitive in detecting stenosis in patients with CSM than in those with OPLL, likely because OPLL patients often have a more limited ROM than CSM patients. Thus, dMRI is a promising new tool that can help spine surgeons in diagnosing and treating CSM. However, further studies are needed to establish the utilization criteria and the clinical value of dMRI.
脊髓型颈椎病(CSM)的诊断基于临床体征和症状,然后通过磁共振成像(MRI)或CT脊髓造影来确诊。由于颈椎具有高度的活动性,且大多数MRI和CT仅在单一位置获取,动态脊髓压迫可能是一种难以捉摸的诊断,常常被漏诊且未被充分理解。在这种情况下,动态MRI(dMRI)已被用于提高在静态MRI无法提供足够信息来确诊或提供额外信息的情况下颈椎管狭窄的诊断准确性。我们对CSM背景下的动态脊髓压迫进行了文献综述,特别强调了动态MRI(dMRI)的作用。尸体研究报告称,脊髓在屈曲时延长,椎管尺寸增加,而在伸展时脊髓松弛并缩短,椎管减小。这些变化可能导致脊髓在运动时受到生物力学应力,尤其是在严重颈椎管狭窄的患者中。大多数在CSM中使用dMRI的研究报告称,与在中立位进行的常规MRI相比,这种成像方式在检测颈椎脊髓压迫方面更敏感,尤其是在颈部伸展时。一些作者还报告了在屈曲时存在隐匿性前侧压迫,但发生率较低。dMRI对于诊断临床病情恶化但中立位静态MRI无明显脊髓压迫的患者行椎板切除术后的动态颈椎脊髓压迫也很有用。最后,dMRI在检测CSM患者的椎管狭窄方面比在OPLL患者中更敏感,可能是因为OPLL患者的活动范围通常比CSM患者更有限。因此,dMRI是一种有前途的新工具,可以帮助脊柱外科医生诊断和治疗CSM。然而,需要进一步研究来确定dMRI的使用标准和临床价值。
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