Diastematomyelia: prenatal ultrasonic appearances

Split Spinal Cord Malformation Fed by Bilateral, Enlarged Radiculopial Arteries

Anatomical variations of the spinal cord are seen in many manifestations; one rare variant that does not stem from a neural tube defect is known as a split cord malformation (SCM). In this variation, a deviation from normal development causes the spinal cord to divide into two hemicords, typically in the lumbar region. In the case described here, a SCM was observed with large, bilateral, radiculopial arteries. To our knowledge, such large vessels in conjunction with a SCM has not previously been documented in the literature. Such variants could be problematic during surgical approaches to the lumbar spine. Herein, we report the case and discuss the development of the findings with relevant clinical applications.

The Value of Prenatal Ultrasonographic Diagnosis of Diastematomyelia

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.

Prenatal diagnosis and clinicopathologic examination of a case with diastematomyelia

Diastematomyelia is a rare form of spinal dysraphism. Here the spinal cord was split into two with a bony or cartilaginous spur, resulting in formation of two hemicords. The prenatal diagnosis of diastematomyelia is possible with ultrasonography. The unique finding is the appearance of echogenic focus within the spinal canal. This condition may not have any clinical sign during prenatal and early years of life but as the child grows, serious neurologic manifestations may occur, commonly termed the "tethered cord syndrome". Here, we report a case of diastematomyelia in which a careful antenatal imaging was performed and postnatal pathologic examination confirmed the diagnosis.

Prenatal diagnosis of diastematomyelia: a case report and review of the literature

Diastematomyelia is a rare congenital disorder in which the spinal cord is divided longitudinally for part of its length. It can be accurately identified in the prenatal period by detailed sonographic examination of the spine. We report a case of diastematomyelia localized to spinal levels T6-T9 diagnosed prenatally at 31 weeks' gestation and review the existing literature on the diagnosis and management of this condition during pregnancy.

Prenatal diagnosis of diastematomyelia: presentation of eight cases and review of the literature

OBJECTIVES

Diastematomyelia is a rare form of spinal dysraphism. We present eight cases of diastematomyelia diagnosed prenatally in our institution as well as a review of the literature in order to determine the prognosis of isolated cases of this very unusual condition.

METHODS

Records of fetuses with diastematomyelia diagnosed in our institution between January 2000 and June 2005 were collected. All liveborn fetuses were examined by a pediatric neurologist. Pre- and postnatal data were analyzed. A search was then conducted using PubMed to review previously reported cases in the literature.

RESULTS

Eight cases of diastematomyelia were diagnosed during the study interval. The mean (range) gestational age at diagnosis was 21 (13-25) weeks. The main sonographic findings were widening of the spinal canal in the coronal view and an additional echogenic focus in the posterior part of the spinal column in the axial view. The diagnosis of associated open spina bifida was made in one fetus with elevated levels of amniotic fluid alpha-fetoprotein (AF-AFP) and acetylcholinesterase (AF-AChE) and the pregnancy was terminated. The other seven cases of diastematomyelia had normal levels of AF-AFP and AF-AChE and were considered isolated. One pregnancy miscarried spontaneously 1 week following amniocentesis and the remaining six were delivered at term. Review of the literature revealed 14 reports involving 26 cases of prenatally diagnosed diastematomyelia. Twelve cases had normal biochemistry and/or no additional abnormalities and all had a favorable outcome.

CONCLUSIONS

When diastematomyelia is not associated with other spinal anomalies, the prognosis is favorable. Prenatal diagnosis is generally made in the second trimester but sonographic signs may be recognized as early as the first trimester. Intrauterine diagnosis of diastematomyelia should facilitate appropriate management of affected cases.

Prenatal Diagnosis of Diastematomyelia in a 15-Week-Old Fetus

OBJECTIVE

A case of prenatal diagnosis of diastematomyelia is presented.

METHODS

A case of fetal diastematomyelia, diagnosed by prenatal sonography, demonstrated the typical sonographic features of this condition. In this case it was detected at 15 weeks of gestation, and presented with a midline echogenic focus in the posterior region of the thoracolumbar spine.

RESULTS

The pregnancy was terminated by induction of labor. The fetus was female and there was a 1-cm long endurated hyperemic lesion at the back of the fetus. We confirmed the diagnosis of diastematomyelia after termination of pregnancy by plain chest and abdominal X-ray and also MRI scanning.

CONCLUSION

Isolated diastematomyelia is a rare form of spinal dysraphism characterized by a sagittal cleft in the spinal cord, conus medullaris and/or filum terminale with splaying of the posterior vertebral elements. Prenatal diagnosis of this anomaly is possible in the early mid-trimester by sonography, thus allowing for early surgical intervention and a favorable prognosis.

Prenatal diagnosis of diastematomyelia

INTRODUCTION

Diastematomyelia, also termed split cord malformation, is a form of occult spinal dysraphism characterized by a cleft in the spinal cord. Prenatal diagnosis of this anomaly is possible by ultrasonography (US), and fetal MRI can be used to diagnose the type of diastematomyelia precisely. Diastematomyelia can be isolated or associated with other dysraphisms, segmental anomalies of the vertebral bodies, or visceral malformations (horseshoe or ectopic kidney, utero-ovarian malformation, and anorectal malformation). We present three cases of fetal diastematomyelia investigated using a multimodal prenatal work-up (US, MRI, 3D-CT).

CASES

The first case, detected at 20 weeks' gestation, had a lumbar meningocele. At 30 weeks' gestation, direct US visualization revealed the division of the spinal cord into two hemicords. This patient illustrates an isolated type II diastematomyelia with a favorable prognosis. The second case, detected at 22 weeks' gestation, presented with disorganization of bony process of the vertebral column with a midline echogenic bony spur, asymmetrical hemicords, and a foot malposition. Fetal MRI at 26 weeks' gestation and CT/3D reconstructed at 32 weeks' gestation confirmed a type I diastematomyelia with orthopedic malposition. The third case, detected at 22 weeks' gestation, presented with widening of the lumbar canal and scoliosis. Prenatal work-up (US, MRI) disclosed other visceral malformations (pelvic kidney), which led to the assumption of a complex polymalformative syndrome. The pregnancy was terminated. Fetopathologic examination disclosed even more visceral malformations (anal atresia and unicorn uterus).

Split spinal cord malformations: report of 22 cases and review of the literature

OBJECT

The aims of this study were to describe the embryological changes that drive the formation of a split spinal cord malformation, analyse the forms of presentation, evaluate the diagnostic procedures and discuss the indications for the different forms of therapy for each case.

METHODS

Clinical and radiological features of 22 cases of split spinal cord malformations (SSCM) are reported. Three groups of patients are considered: group a, patients with signs of tethered cord or scoliosis; group b, patients with midline cutaneous stigmata and group c, patients with a meningocele or meningomyelocele.

CONCLUSION

While CT scan is particularly useful for the evaluation of vertebral bodies and posterior arch abnormalities and spur characteristics in SSCM, MRI gives complementary information on the anatomy of spinal cord, dural sac, conus and filum terminale and permits the exclusion of associated lesions such as hydro-syringomyelia, dermal sinus or dermoid and epidermoid cysts. Surgery should be considered indicated in all cases of SSCM, even the asymptomatic ones, except in very badly handicapped meningomyelocele patients with nonprogressive disability and type II SSCM.

Sonographic diagnosis of diastematomyelia in utero: a case report and literature review

Fetal diastematomyelia is a rare form of spinal dysraphism that is characterized by a complete or incomplete division of the spinal cord by an osseous or fibrocartilaginous septum. A case of diastematomyelia, which was detected on the routine third trimester detailed ultrasound scan, is presented. The diagnosis was based on the detection of an echogenic focus in the posterior aspect of the spine in association with widening of the interpedicular vertebral space. The case illustrates that diastematomyelia can occur in the absence of overt spina bifida and that prenatal detection will allow timely postnatal investigation and treatment. Prenatal literature is further reviewed to assess the clinical significance of this finding.

Prenatal ultrasound evaluation of fetal diastematomyelia: two cases of type I split cord malformation

Isolated diastematomyelia is a rare form of spinal dysraphism characterized by a sagittal cleft in the spinal cord, conus medullaris and/or filum terminale with splaying of the posterior vertebral elements. This condition is the result of the presence of an osseous or fibrocartilaginous septum producing a complete or incomplete sagittal division of the spinal cord into two hemicords. It may be isolated or associated with other segmental anomalies of the vertebral bodies. Prenatal diagnosis of this anomaly is possible in the early midtrimester by sonography, thus allowing for early surgical intervention and a favorable prognosis. Two cases of fetal diastematomyelia diagnosed by prenatal sonography are presented, each demonstrating the typical sonographic features diagnostic of this condition. The first case, detected at 28 weeks' gestation, presented with disorganization of the bony processes of the vertebral column with a midline echogenic focus. The second fetus, diagnosed at 17 weeks' gestation, had a similar appearance with widening of the posterior elements and the presence of a midline echogenic bony spur. Postnatally, both infants underwent magnetic resonance imaging for a definitive diagnosis. Surgical repair of the defect was performed in the neonatal period in both cases.

Diastematomyelia in two sisters

Diastematomyelia is a rare spinal cord anomaly that usually occurs in a non-syndromal, sporadic manner; however, few familial cases have been reported. We report on diastematomyelia in 2 sisters with variable expressivity. The spinal column is divided by osseous or fibrous tissue. This may be responsible for the variable expressivity. Most cases previously reported were females. This suggests X-linked dominant inheritance with lethality in hemizygous males or female sex limitation of a multifactorial trait.

Split spinal cord malformations in children

OBJECT

The authors reviewed and analyzed information on 74 patients with split spinal cord malformations (SSCMs) treated between January 1, 1980 and December 31, 1996 at their institution with the aim of defining and classifying the malformations according to the method of Pang, et al.

METHODS

Computerized tomography myelography was superior to other radiological tools in defining the type of SSCM. There were 46 girls (62%) and 28 boys (38%) ranging in age from less than 1 day to 12 years (mean 33.08 months). The mean age (43.2 months) of the patients who exhibited neurological deficits and orthopedic deformities was significantly older than those (8.2 months) without deficits (p = 0.003). Fifty-two patients had a single Type I and 18 patients a single Type II SSCM; four patients had composite SSCMs. Sixty-two patients had at least one associated spinal lesion that could lead to spinal cord tethering. After surgery, the majority of the patients remained stable and clinical improvement was observed in 18 patients.

CONCLUSIONS

The classification of SSCMs proposed by Pang, et al., will eliminate the current chaos in terminology. In all SSCMs, either a rigid or a fibrous septum was found to transfix the spinal cord. There was at least one unrelated lesion that caused tethering of the spinal cord in 85% of the patients. The risk of neurological deficits resulting from SSCMs increases with the age of the patient; therefore, all patients should be surgically treated when diagnosed, especially before the development of orthopedic and neurological manifestations.

Prenatal diagnosis of diastematomyelia

Fetal diastematomyelia, a malformation due to a longitudinal split of the cord, was diagnosed during the third trimester. Diagnosis was based on the visualization of a sagittal bony spur in the thoracolumbar spinal canal, associated with enlargement of the canal, hemivertebrae and spina bifida without a meningocele.

Sonographic Evaluation of the Spine in Infants and Neonates

Ultrasound is a rapid, noninvasive, cost-effective method of evaluating the spine in infants younger than six months of age. This report reviews sonographic scan procedure and normal sonographic spinal anatomy, and illustrates the sonographic appearance of occult spinal anomalies, such as meningocele, meningomyelocele, tethered cord, diastematomyelia, and sacrococcygeal teratoma.

Prenatal diagnosis of fetal diastematomyelia in a pregnancy exposed to acyclovir

A rare form of spinal dysraphism, diastematomyelia, was diagnosed in a pregnancy exposed to acyclovir at the time of implantation. The prenatal diagnosis was based on the ultrasound examination of the fetus. Pathologic evaluation of the postabortion fetus confirmed the diagnosis. The use of acyclovir in pregnancy and associated anomalies are reviewed.

Occult diastematomyelia in adults--report of two cases

Two cases of diastematomyelia discovered in adults with minimal symptoms are described. In one case the presence of an associated thoracic neurenteric cyst supports the theory that a diastematomyelic spur represents a persistent neurenteric canal. The imaging findings are described and the incidence of diastematomyelia in adults is briefly discussed on the basis of cases previously reported in the literature.