Prenatal diagnosis of tethered spinal cord associated with sacrococcygeal teratoma

Tethered spinal cord is mostly caused by myelomeningocele and lipomyelomeningocele, while dermal sinus tract, diastematomyelia, lipoma, tumor, thickened/tight filum terminale, spinal trauma, and spinal surgery are among the other causes. Prenatal diagnosis of tethered cord has been reported, and it is usually associated with neural tube defects. We present an atypical presentation of a tethered spinal cord, which was associated with a sacrococcygeal teratoma and was diagnosed in the 23rd week of pregnancy by ultrasonography. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 44 :506–509, 2016     

三维超声容积对比成像和断层超声成像技术观察胎儿脊髓栓系

目的 探讨三维超声容积对比成像（VCI）及断层超声成像（TUI）技术观察胎儿脊髓圆锥（CM）所对应的椎体位置、脊髓腰膨大的大小及形态,评估是否存在胎儿脊髓栓系（TC）的价值。方法 记录病例组17胎脊柱区病变或畸形伴TC胎儿的CM末端位置和腰膨大位置,测量脊髓腰膨大处的横径、前后径。并与300胎正常胎儿进行对比分析。结果 随着孕周的增长CM末端位置上升,300胎正常胎儿的CM末端均位于L3或L3以上椎体水平。正常胎儿脊髓腰膨大的横径和前后径均与孕周有较好的线性关系,线性回归方程为：腰膨大横径（mm）=0.677+0.147×孕周（R²=0.836,P<0.05）,腰膨大前后径（mm）=－0.994+0.152×孕周（R²=0.894,P<0.05）。与正常胎儿相应孕周正常值比较,病例组TC胎儿脊髓腰膨大的前后径减小（P=0.002）,横径差异无统计学意义（P=0.082）。结论 通过三维超声VCI及TUI技术对胎儿CM位置进行判定并分析脊髓腰膨大的形态变化,可为TC胎儿的产前诊断提供有价值的参考依据。     

超声测距法定位中晚孕期胎儿脊髓圆锥位置

目的 通过二维和三维超声测量中晚孕期胎儿脊髓圆锥(CM)末端至骶尾部最后一个骨化中心(CS)的距离来定位CM,探索胎儿期CM位置变化的规律。方法 采用二维超声成像及三维超声表面成像检查孕19~34周566名孕妇,测量胎儿CS距离。采用3D容积存储系统存储图像、real-time 3D View软件离线分析,采用组内相关系数(ICC)评价二维与三维超声检测CS距离的一致性。分析胎儿期各孕周CS距离变化规律。结果 共253名二维与三维超声成像测量的CS距离一致性好(ICC=0.974)。CS距离与胎儿孕周呈正相关(r=0.956,P<0.001),线性回归方程为:Y=0.262X-2.508(Y:CS距离,X:孕周)。结论 三维超声表面成像测量CS距离的方法简单有效,适用于临床;CS距离与胎儿GA间的相关性可作为胎儿期CM是否低置的判断标准。     

Implantation of cauda equina nerve roots through a biodegradable scaffold at the conus medullaris in rat

Background contextTraumatic injuries occurring at the conus medullaris of the spinal cord cause permanent damage both to the central nervous system and to the cauda equina nerve roots.PurposeThis proof-of-concept study was to determine whether implanting the nerve roots into a biodegradable scaffold would improve regeneration after injury.MethodsAll experimental works involving rats were performed according to the approved guidelines by the Mayo Clinic Institutional Animal Care and Use Committee. Surgical procedures were performed on 32 Sprague-Dawley rats. Four ventral cauda equina nerve roots were reimplanted either directly into the ventral cord stump or through a poly(lactic-co-glycolic acid) (PLGA) scaffold. These experimental groups were compared with a control group in which the nerves were inserted into a muscle fascia barrier that was placed between the spinal cord and the nerve roots. Animals were sacrificed at 4 weeks.ResultsThere was no difference in motor neuron counts in the spinal cord rostral to the injury in all treatment groups, implying equal potential for the regeneration into implanted nerve roots. One-way analysis of variance testing, with Tukey post hoc test, showed a statistically significant improvement in axon regeneration through the injury in the PLGA scaffold treatment group compared with the control (p<.05, scaffold n=11, control n=11).ConclusionsThis pilot study demonstrated that a PLGA scaffold improved regeneration of axons into peripheral nerve roots. However, the number of regenerating axons observed was limited and did not lead to functional recovery. Future experiments will employ a different scaffold material and possible growth factors or enzymes to increase axon populations.     

腰骶段脊髓室管膜瘤的MRI诊断及其鉴别诊断

目的:分析腰骶段脊髓圆锥及终丝室管膜瘤的MRI影像特点,提高该病的诊断准确性和对鉴别诊断的认识。方法:回顾性分析经手术病理证实的14例腰骶段脊髓内室管膜瘤,所有病例均行MRI平扫和增强扫描,分析肿瘤的部位、病理类型、生长方式和信号特点、强化方式、有无囊变,观察有无含铁血黄素沉积。结果:肿瘤发生在脊髓圆锥2例,终丝12例,10例可见囊变,11例T₂W1见低信号,13倒不均一明显强化。结论:MRI可以反映脊髓内室管膜瘤MRI特征,是诊断和鉴别诊断的重要手段,有助于提高诊断正确率,有含铁血黄素沉积时倾向于诊断室管膜瘤。     

Saddle sensation is preserved in a few patients with cauda equina or conus medullaris lesions1

Although saddle sensory deficit seems the most useful clinical sign in the diagnosis of a cauda equina or conus medullaris lesion, findings of previous studies were controversial. The aim of the present study was to try to resolve this issue. The data from the author's series of patients with clinical, electrodiagnostic and radiological findings compatible with a cauda equina lesion were reviewed. Of the 117 patients in the series, 11 (10 men) did not have a saddle sensory deficit. These 11 patients had less severe sacral dysfunction than the others, and none of them needed urgent surgical intervention. They all had electromyographic (EMG) signs of a significant motor fibre lesion, and in seven men the sacral (penilo‐cavernosus) reflex was clinically abnormal. The study revealed normal saddle sensation in approximately 10% of patients with cauda equina or conus medullaris lesions. Dissociation between preserved touch sensation and abnormal EMG findings, as well as dissociation between preserved touch sensation and a non‐elicitable penilo‐cavernosus reflex might be explained by preservation of the thinner sensory nerve fibres, which are more resistant to compression. Although, saddle sensory loss seems to identify patients who might benefit from urgent spinal imaging and surgery, further diagnostic evaluation is also indicated in patients with normal saddle sensation, particularly due to the increased frequency of spinal tumours found in this subgroup.     

Cystic dilatation of ventriculus terminalis in adults: MRI

We report the MRI findings in two patients with cystic dilatation of the ventriculus terminalis. The latter is usually a tiny ependyma-lined cavity of the conus medullaris. In both cases the markedly dilated ventriculus terminalis was seen as a rounded cavity with regular margins, the content of which gave the same signal as cerebrospinal fluid with all MR pulse sequences. No contrast enhancement was seen. Received: 7 February 1997 Accepted: 2 May 1997     

国人脊髓圆锥位置的磁共振成像研究

目的通过MRI研究非脊柱脊髓畸形的国人人群圆锥位置的变化.方法应用1.5T MRI机对1199例病人行腰椎MR扫描,自旋回波T1加权、正中矢状位像上观测其圆锥末端的位置.根据其与相应椎体的上、中、下1/3及椎间盘的对应关系定位.结果圆锥末端的平均位置为L1的下1/3水平(范围T12的中1/3～L3的上1/3),圆锥末端的位置呈正态分布,女性圆锥位置低于男性(P<0.001),各年龄段无差别(P>0.05).结论 MRI可以观测到圆锥末端的位置,对临床椎管内麻醉、腰椎管手术和椎管造影有重要参考意义.     

Bronchogenic cyst of the conus medullaris with spinal cord tethering: a case report and review of the literature

Bronchogenic cysts (BCs) are congenital malformations that originate from remnants of the primitive foregut. Intraspinal BCs, especially those of the conus medullaris are rare with only one case reported until now. To date, a bronchogenic cyst with spinal cord tethering has not been previously reported. We reviewed the clinical course of a 44-year-old woman, who presented with low back pain and leg weaknesss as well as sphincter disturbance. Magnetic resonance imaging showed an intradural oval mass located at the conus medullaris. A tethered cord was also observed, as well as a dermal sinus tract. The mass was totally removed after an L3-L4 laminectomy without detethering during operation. Pathologic examination confirmed the diagnosis of bronchogenic cyst. By six months after treatment, the patient had experienced nearly complete recovery. The review of literature indicated that detethering was performed in most reported cases of neurenteric cysts with spinal cord tethering, and one of six patients was diagnosed with a postoperative recurrence. The co-existence of bronchogenic cyst and a tethered spinal cord would imply associated developmental errors in embryogenesis. It is worth noting that whether detethering is necessary after the cyst removal.