Stamates Melissa M, Frim David M, Yang Carina W, Katzman Gregory L, Ali Saad
1Section of Neurosurgery, and.
2Department of Radiology, The University of Chicago, Illinois.
J Neurosurg Pediatr. 2018 Jan;21(1):4-10. doi: 10.3171/2017.3.PEDS16596. Epub 2017 Oct 27.
OBJECTIVE Tethered cord syndrome (TCS) is a neurosurgical disorder with varied clinical manifestations believed to result from vascular compromise due to stretch forces on the spinal cord. Conventional supine MRI findings may include a low-lying conus medullaris, thickened or fat-infiltrated filum terminale, or lipoma; however, imaging sensitivity and specificity for tethered cord can be low. The purpose of this study was to evaluate the utility of prone MRI in the diagnosis of tethered and retethered spinal cord. METHODS Medical records were reviewed in 41 patients who underwent surgical release of tethered cord and in whom preoperative prone MRI sequences were available. Patients were divided into Group 1 (new TCS diagnosis) and Group 2 (recurrent TCS after previous untethering). Absolute conus ventral motion and motion as a percentage of canal width between supine and prone positions was measured in these 2 groups via sagittal T2-weighted sequences; these groups were compared with 30 consecutive patients (Group 3) who were classified as the normal control group. RESULTS The mean ventral motion was as follows: Group 1 (absolute: 0.5 ± 0.5 mm [range 0-2.4 mm]; canal percentage: 3.7% ± 3.9% [range 0%-16.3%]); Group 2 (absolute: 0.4 ± 0.7 mm [range 0-2.6 mm]; canal percentage: 2.2% ± 3.7% [range 0%-14.0%]); and Group 3 (absolute: 3.4 ± 1.3 mm [range 1.4-5.6 mm]; canal percentage: 22.0% ± 7.2% [range 10.5%-36.1%]). Whereas 38/41 surgically treated patients with TCS had diminished (< 10% canal width) ventral motion on preoperative MRI, 30/30 controls had > 10% canal width motion. Sensitivity and specificity were thereby calculated as 92.7% and 100%, respectively. CONCLUSIONS In the present series, prone imaging is found to be a sensitive and specific tool, and the authors believe it may have a role as supportive evidence in the diagnosis of tethered and retethered spinal cord.
目的 脊髓拴系综合征（TCS）是一种神经外科疾病，临床表现多样，被认为是由于脊髓受到牵拉力导致血管受压所致。传统仰卧位磁共振成像（MRI）表现可能包括低位脊髓圆锥、终丝增厚或脂肪浸润，或脂肪瘤；然而，MRI对脊髓拴系的成像敏感性和特异性可能较低。本研究的目的是评估俯卧位MRI在诊断脊髓拴系和再拴系中的应用价值。方法 回顾了41例行脊髓拴系松解手术且术前有俯卧位MRI序列的患者的病历。患者分为1组（新诊断的TCS）和2组（既往松解术后复发性TCS）。通过矢状位T2加权序列测量这两组患者仰卧位和俯卧位之间脊髓圆锥的绝对腹侧移动度以及移动度占椎管宽度的百分比；将这两组与30例连续患者（3组）进行比较，3组被分类为正常对照组。结果 平均腹侧移动度如下：1组（绝对值：0.5±0.5mm[范围0 - 2.4mm]；椎管百分比：3.7%±3.9%[范围0% - 16.3%]）；2组（绝对值：0.4±0.7mm[范围0 - 2.6mm]；椎管百分比：2.2%±3.7%[范围0% - 14.0%]）；3组（绝对值：3.4±1.3mm[范围1.4 - 5.6mm]；椎管百分比：22.0%±7.2%[范围10.5% - 36.1%]）。41例接受手术治疗的TCS患者中，38例在术前MRI上腹侧移动度减小（<椎管宽度的10%），而30例对照组患者移动度>椎管宽度的10%。由此计算出敏感性和特异性分别为92.7%和100%。结论 在本系列研究中，发现俯卧位成像为一种敏感且特异的工具，作者认为其在脊髓拴系和再拴系的诊断中可能作为支持性证据发挥作用。
