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Myelocystocele. A, Sagittal ultrasound of the lower back of a 37-week-old fetus illustrates the location of the CM (arrowhead) and identifies a ventriculus terminalis in the lower lumbar spine. Spinal dysraphism was suggested to underlay normal skin, but was not clearly seen. B, Postnatal ultrasound of a lumbar mass demonstrates a spinal defect at L3/L4 with neural elements extending dorsally (arrow). C, Postnatal MR imaging shows a tethered cord (arrowhead) and skin-covered neural tube defect.
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Tethered spinal cord is associated with closed and open neural tube defects. With prenatal screening, spinal defects are consistently diagnosed during fetal life. We show that the conus medullaris can be seen well with prenatal ultrasound, and the diagnosis of tethered spinal cord can be made during fetal life. In this pictorial essay, we show exam...
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Arnold Chiari malformation is nearly always associated with mye-lomeningocele, but it is rarely associated with other spine and spinal cord anomalies such as diastematomyelia and hemimyelo-meningocele, as well as osseus and visceral anomalies. We report the case of a male newborn with Arnold Chiari malformation associated with diastematomyelia, syr...
Objective: Diastematomyelia is a rare congenital spine and spinal cord malformation in which the spinal cord is divided into two parts by the osseous or fibrous septum. The incidence of diastematomyelia in patients with the most severe forms of congenital scoliosis is much higher than its general incidence in the population. When performing surgeri...
Lipomyelomeningocele (LMMC) is a type of congenital occult spinal dysraphism consisting of the presence of lipomatous tissue attached to the dorsal spinal cord, which protrudes though a spinal defect along with the menings or spinal cord to form a posterior mass under the skin. LMMC is the commonest cause of congenital tethering (tethered cord synd...
Citations
... Ultrasound is important for prenatal diagnosis of meningoceles and myelocystoceles [32,33]. Postnatally, sonography shows a cystic mass(es) extending past vertebral arch defects [34]. No neural tissue is demonstrated in meningocele [35]. ...
... No neural tissue is demonstrated in meningocele [35]. Associated tethered cord may be seen [34,35]. In meningoceles, continuity between the central canal and subarachnoid spaces may be illustrated with the aid of sonography [35]. ...
... In myelocystocele, the interface of the terminal syrinx and meningocele is often complex. Either or both may herniate into the subcutaneous tissues, either may be the larger defect, or they may wrap around each other [31,33,34,36]. While sonography alone may identify the presence of the terminal syrinx, meningocele, subcutaneous cystic structure(s), and vertebral defects, it may be insufficient for a complete description. ...
A broad spectrum of spinal pathologies can affect the pediatric population. Ultrasound (US) is the primary modality for pediatric spine assessment due to its widespread availability, non-requirement of sedation, and absence of ionizing radiation. Supplementing this, MRI offers an in-depth exploration of these conditions, aiding in preoperative strategizing. In this review, we examine the clinical indications, methodologies, and protocols for US and MRI scans of the pediatric spine. Additionally, we illustrate normal pediatric spinal anatomy, highlighting several examples of normal variants that are often misinterpreted. Through a series of case-based illustrations, we offer a comprehensive overview of various pathological conditions such as tethered cord, spinal dysraphism, spinal lipoma, diastematomyelia, and dermal sinus tract, among others. Furthermore, we explore the correlation between US and MRI findings for these lesions, employing real-world cases to enhance our understanding of this topic.
... Anomalies associated with tethered cord include occult spinal dysraphism, myelocystocele, lipomyelomeningocele, fetal back mass, intradural lipoma, vertebral body anomalies, and others. 5 However, it is difficult to detect subtle lesions. If the presence of a low-lying CM could be detected, this might raise suspicion for these associated abnormalities. ...
Objective
This study explored the use of 2‐dimensional (2D) ultrasound scans for the quantitative assessment of the fetal conus medullaris (CM) position and its correlation with gestational age (GA).
Methods
This was a prospective study. We identified the first sacral vertebra (S1) by intersection of 2 lines in 2D scans, then counted upward from S1 to determine the CM level and recorded the number of ossified sacral vertebral bodies. A quantitative assessment of the CM position was performed by measuring the distance between the CM and the midpoint of the S1 (CM–S1). The correlation between the CM‐S1 distance and GA was evaluated.
Results
We determined the CM level by identifying S1 first in 521 fetuses (GA, 20–38 weeks). The CM position in 70% of cases was at the L2 and L2–3 level, and at the L2 level or above after 37 weeks. The number of ossified sacral veterbral bodies was not consistent. CM–S1 measurements were easy to perform. A significant positive correlation between CM–S1 distance and GA was observed (R² = .89, P < .05). The best‐fit formula was: CM–S1 distance = 1.57 × GA – 16.43. The normal reference range was established and the fifth percentile was calculated for each GA.
Conclusions
S1 was easily identified, and the CM position relative to S1 was useful. There was a substantial correlation between CM–S1 and GA. Below the fifth percentile it was suggested that tethered cord may exist.
... The diagnosis of TCS can be confirmed by ultrasonography if the medullary cone is below the L3-L4 level after 18 weeks' gestation. 23 In addition, prenatal MRI is slightly superior to ultrasonography in examination of the spinal cord during mid-and late pregnancy, because the latter might be affected by factors such as oligohydramnios, maternal obesity, and fetal position. Moreover, ultrasonography might also be influenced by the acoustic shadow of the vertebral bodies. ...
Objectives:
To evaluate the value of prenatal ultrasonographic diagnosis of diastematomyelia, and to provide a basis for the diagnosis and differential diagnosis of fetal diastematomyelia.
Methods:
Four fetuses with suspected diastematomyelia based on prenatal ultrasonography are presented. Detailed prenatal ultrasonography was performed to examine spinal cord abnormalities. The region of interest-based spine sagittal plane was defined and 3D volumetric scans were performed, as needed. Images were stored and compared with MRI or ultrasonographic images after abortion.
Results:
In the four cases of diastematomyelia diagnosed by prenatal ultrasonography, two were confirmed by MRI after birth, and the other two were confirmed by autopsy and pathologic examination after abortion. Varying degrees of spine or spinal cord deformities were noted. Two pregnancies were terminated, and two newborns underwent surgery.
Conclusions:
Prenatal ultrasonography contributes to the diagnosis of diastematomyelia and provides a basis for prenatal counseling and prognosis.
... 2,4 During this period, a conus medullaris positioned at or below L4 or displaced dorsally is highly suggestive of closed spinal dysraphism. Sohaey et al 5 showed examples of tethered cord in a variety of fetuses with spine anomalies. The prognosis of prenatally diagnosed TSC is still unclear, as only a few cases have been reported. ...
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.
... 27 Detection of a terminal ventricle by prenatal ultrasound in the third trimester has been described as a cystic mass at the distal portion of a widened spinal canal. 29 However, it may be difficult to detect such lesions at earlier gestations, particularly if they are small. There have been no case reports of prenatal sonographic detection of a spinal dermal sinus. ...
Objective: To develop a classification system for congenital spine anomalies detected by prenatal ultrasound.
Methods: Data were collected from fetuses with spine abnormalities diagnosed in our institution over a five‐year period between June 2005 and June 2010. The ultrasound images were analysed to determine which features were associated with different congenital spine anomalies. Findings of the prenatal ultrasound images were correlated with other prenatal imaging, post mortem findings, post mortem imaging, neonatal imaging, karyotype, and other genetic workup. Data from published case reports of prenatal diagnosis of rare congenital spine anomalies were analysed to provide a comprehensive work.
Results: During the study period, eighteen cases of spine abnormalities were diagnosed in 7819 women. The mean gestational age at diagnosis was 18.8w ± 2.2 SD. While most cases represented open NTD, a spectrum of vertebral abnormalities were diagnosed prenatally. These included hemivertebrae, block vertebrae, cleft or butterfly vertebrae, sacral agenesis, and a lipomeningocele. The most sensitive features for diagnosis of a spine abnormality included flaring of the vertebral arch ossification centres, abnormal spine curvature, and short spine length. While reported findings at the time of diagnosis were often conservative, retrospective analysis revealed good correlation with radiographic imaging. 3D imaging was found to be a valuable tool in many settings.
Conclusions: Analysis of the study findings showed prenatal ultrasound allowed detection of disruption to the normal appearances of the fetal spine. Using the three features of flaring of the vertebral arch ossification centres, abnormal spine curvature, and short spine length, an algorithm was devised to aid with the diagnosis of spine anomalies for those who perform and report prenatal ultrasound.
Objective:
We assessed the frequency and type of associated congenital anomalies encountered with fetal tethered spinal cord (TSC) determined prenatally.
Method:
A retrospective review was conducted based on the associated fetal abnormalities following diagnosis of low-lying fetal conus medullaris during the prenatal ultrasound.
Results:
Of the 26 fetuses with low-lying conus medullaris, four were solitary TSC and 22 had TSC combined with associated congenital malformations, including four cases with spina bifida occulta, four cases with spina bifida aperta, one case with severe hydrocephalus, and 13 cases with multisystem congenital malformations. Among all the 13 cases with combined multisystem congenital malformations, four cases had vertebral defects, anal anomalies, cardiac defects, trachea-esophageal fistula, renal anomalies, and limb anomalies (VACTERL) syndrome, two cases had combined kidney development abnormalities, one case had cloacal exstrophy (OEIS syndrome), and six cases had chromosomal abnormalities (one case of chromosome 7q deletion, two cases of trisomy 13 syndrome, one case of trisomy 18 syndrome, one case of trisomy 9 syndrome, and one case of chromosome 4p deletion).
Conclusions:
Low-lying conus medullaris found during prenatal ultrasound examination were often associated with neural tube malformations or multi-systemic complex developmental malformations. The frequency of chromosomal abnormalities was 23.1%.
Résumé
La myéloméningocèle (MMC) est une malformation congénitale grave, responsable de déficits moteur et sensitif des membres inférieurs, d’une incontinence et d’une déficience cognitive. Son dépistage, parfois dès le premier trimestre est l’un des objectifs majeurs de la médecine fœtale moderne, encouragé par l’avènement d’une chirurgie prénatale permettant une amélioration significative de la fonction motrice, de la déambulation et du taux de dérivation ventriculo-péritonéale chez les enfants opérés in-utero. Du dépistage à l’évaluation pronostique pré et post-opératoire, l’échographie prénatale est désormais un outil indispensable dans la prise en charge anténatale de cette pathologie. Elle permet à l’aide des modes triplan et volumique de préciser le niveau rachidien de la MMC qui reste le principal marqueur pronostic en anténatal pour la fonction motrice et la déambulation, l’incontinence et la nécessité d’une dérivation ventriculo-péritonéale. Un examen échographique minutieux et systématique permet également d’évaluer la sévérité et l’évolution de la ventriculomégalie, de rechercher des anomalies cérébrales, médullaires ou rachidiennes associées ou d’éliminer des critères d’exclusion à la chirurgie in-utero comme la cyphose sévère ou des anomalies corticales graves. De nouveaux outils importés de l’évaluation post natale, comme l’évaluation échographique « métamérique » de la mobilité des membres inférieurs semblent prometteurs tant lors de l’examen initial qu’en post-opératoire. L’échographie, associée à l’IRM fœtale et la biologie moléculaire, rend dorénavant possible une évaluation pronostique très personnalisée de ces fœtus porteurs de MMC et permet d’informer au mieux le couple sur les bénéfices attendus et les limites d’une chirurgie fœtale.
Aim:
The aim of this study is to investigate if three-dimensional (3D) ultrasonography is a reliable diagnosis method for prenatal tethered cord syndrome (TCS) by measuring fetal conus distance (CD) in comparison to two-dimensional (2D) ultrasonography and magnetic resonance imaging (MRI).
Methods:
This retrospective study included 468 normal fetuses as control group and 14 TCS fetuses as tethered group. CD were measured by 2D, 3D ultrasonography and MRI, and the reliability and repeatability of CD measurement was compared between two experienced ultrasound specialists or among the multiple measurements for each specialist.
Results:
The results showed that 3D ultrasonography was superior to 2D ultrasonography in the repeatability of measuring CD. The CD were positively correlated to gestational ages in control group (P < 0.05). The CD of TCS group (-1.342 ± 0.124) was significantly shorter than that of normal control group (0.013 ± 0.965) (P < 0.01). There were no significant differences in the effectiveness of locating conus medullaris and measuring CD between 3D ultrasonography and MRI.Conclusion Measurement of fetal CD with 3D ultrasonography can serve as a reliable and cost-effective prenatal diagnosis method for TCS.
Neural Tube Defects (NTD) constitute a heterogeneous group of congenital malformations which includes: anencephaly, cephalocele and spina bifida. The 2D and 3D ultrasound techniques along with the magnetic resonance imaging have been used to identify and characterize the majority of clinical relevant lesions. Meningomyelocele - the most frequent NTD - has been increasingly managed through fetal surgery, with promising results. This article pretends to review updated information about prenatal diagnosis and management of NTDs.
The objective of this review is to describe antenatal and postnatal imaging criteria, which allow diagnosis and aid workup, prognostication and treatment of developmental anomalies of the caudal cell mass. The lower spinal cord (conus medullaris), filum terminale and inferior lumbar and sacral nerve roots develop from the caudal cell mass, a remnant of the embryologic primitive streak composed of undifferentiated pluripotential cells. Anomalous caudal cell mass development can manifest as tight filum terminale, caudal dysgenesis, terminal myelocystocele, anterior sacral meningocele or sacrococcygeal teratoma. Lower spinal cord development occurs simultaneously and in topological proximity to the developing lower gastrointestinal and genitourinary tracts, leading to coexistent malformations.
We review the embryology of the caudal cell mass, describe the role of antenatal and postnatal imaging for diagnosing, staging, prognosticating and guiding intranatal or postnatal intervention for developmental anomalies of this region and briefly discuss clinical manifestations and treatment goals and strategies. An overview of antenatal imaging diagnosis of associated multisystem abnormalities will be provided where applicable.
