diastematomyelia

School ager
with skin stigmata along the spine. AP radiograph of the spine (left) suggests a linear piece of bone in the center of the spinal canal at the L2-L3 level. Axial CT without contrast of the spine at the L2-L3 level (right) shows the spinal cord and thecal sac are bisected by a boney bridge in the center of the spinal canal. There is also evidence of vertical fusion of the spinal lamina.The diagnosis was diastematomyelia.
pediatricimaging.org • CC-by-nc-sa 4.0
Infant with a
faun’s tail on the midline of their back. AP image from a vintage lumbar myelogram exam after injection of contrast in the spinal canal shows an ovoid filling defect in the center of the spinal canal from L1 to L2.The diagnosis was diastematomyelia.
pediatricimaging.org • CC-by-nc-sa 4.0
Antenatal and
postnatal imaging of a double diastematomyelia without other malformation. Axial view at level T10-L2 of the dorso-lumbar junction demonstrating two hemicords separated by hyperechogenic spur with acoustic shadowing.
www.eurorad.org • CC by-nc-sa-4.0
Antenatal and
postnatal imaging of a double diastematomyelia without other malformation. Axial ultrasound in the supine position and axial T2-weighted TSE MR demonstrating two hemicords in separate dural sacs with an incomplete bony spur emerging between the hemicords from the posterior wall of the vertebra.
www.eurorad.org • CC by-nc-sa-4.0
Magnetresonanztomographie
(T2 axial und sagittal) einer Diastematomyelie. Der Befund war bei der 80-jährigen Frau bisher nicht bekannt. Leider können keine Angaben zu eventuellen Einschränkungen der Patientin gemacht werden. Aber offenbar kann man damit alt werden.
Wikipedia • CC BY-SA 3.0
Syringohydromyelie
und Diastematomyelie unmittelbar daran angrenzend. Kein Nachweis eines sagittalen, duralen Strangs, der das Myelon teilt. Bildgebend war nicht zwischen einer Syringomyelie (Flüssigkeit um den Zentralkanal) und einer Hydromyelie (Erweiterung des Zentralkanals) zu unterscheiden, weshalb der Begriff Syringohydromyelie zusammenfassend gewählt wird.
Wikipedia • CC BY-SA 4.0
School ager
with fauns tail on the back. Axial CT without contrast of the lumbar spine shows a piece of bone bisecting the spinal canal.The diagnosis was diastematomyelia.
pediatricimaging.org • CC-by-nc-sa 4.0
Preschooler
with a faun’s tail in the midline of the back at the thoraco-lumbar junction. AP radiograph of the thoracolumbar spine shows a bone spur in the midline of the spinal canal at the T12-L1 level.The diagnosis was diastematomyelia.
pediatricimaging.org • CC-by-nc-sa 4.0
School ager
with a faun’s tail in the middle of the lower back. Vintage AP tomogram obtained through the posterior elements of the lumbar spine (left) shows a linear piece of bone in the midline between the L3 and L4 vertebral bodies. Axial CT without contrast of the spine (right) through the L3/L4 disc space shows a piece of bone in the center of the spinal canalThe diagnosis was diastematomyelia.
pediatricimaging.org • CC-by-nc-sa 4.0
Posterior-only
surgical correction with heavy halo-femoral traction for the treatment of rigid congenital scoliosis associated with split cord malformation. A patient with RCS accompanied by SCM. a-b Preoperative radiographs show that coronal Cobb angle was 62°.c-d Preoperative bending radiograph of the convex side shows that Cobb angle was 45.6° and flexibility was 26.45%.e Preoperative CT indicates mixed defects including failure of segmentation and formation. f-g Preoperative MRI indicates SCM type 2. h After heavy halo-femoral traction, the coronal Cobb angle was reduced to 38.2°.i-j After posterior-only surgical correction, postoperative radiographs show that coronal Cobb angle was 21.4°, and correction rate was 65.48%. k-l postoperative radiographs at 36 months after surgery show that coronal Cobb angle was 22.4°, and no signs of neurological impairment were found at the final follow-up stage
bmcmusculoskeletdisord.biomedcentral.com • CC-by-4.0
School ager
with fauns tail on the back. AP vintage conventional myelogram at the level of the thoracolumbar junction shows an oval filling defect in the center of the thecal sac.The diagnosis was diastematomyelia.
pediatricimaging.org • CC-by-nc-sa 4.0
Radiopaedia • CC-by-nc-sa 3.0 • de

Diastematomyelia, also known as a split cord malformation, refers to a type of spinal dysraphism (spina bifida occulta) when there is a longitudinal split in the spinal cord.

Terminology

Although traditionally it has been distinguished from diplomyelia (in which the cord is duplicated rather than split) the term split cord malformation is advocated to encompass both conditions . For the purposes of this article, the terms diastematomyelia and split cord malformation are used interchangeably.

Epidemiology

Split cord malformations are a congenital abnormality and account for ~5% of all congenital spinal defects .

Clinical presentation

The majority of patients with diastematomyelia are symptomatic, presenting with signs and symptoms of tethered cord, although patients with mild type II (see below) may be minimally affected or entirely asymptomatic . Presenting symptoms include:

  • leg weakness
  • low back pain
  • scoliosis
  • incontinence

Patients with diastematomyelia also frequently have other associated anomalies including:

Pathology

Classification

Split cord malformations are divided into two types according to the presence of a dividing septum and single vs dual dural sac:

  • type I: duplicated dural sac, with common midline spur (osseous or fibrous) and usually symptomatic
  • type II: single dural sac containing both hemicords; impairment less marked
Type I

Type I is the classic diastematomyelia, characterized by :

Type II

Type II is milder than type I, and lack many of the features of latter:

  • single dural sac and no spur/septum
  • cord divided, sometimes incompletely so
  • hydromyelia may be present
  • spina bifida may be present, but other vertebral anomalies are far less common
  • patients a less symptomatic or may even be asymptomatic

Radiographic features

Split cord malformations are more common in the lower cord but can sometimes occur at multiple levels.

  • 50% occur between L1 and L3
  • 25% occur between T7 and T12

An associated bony, cartilaginous or fibrous spur projecting through the dura mater forwards from the neural arch is visible in 33% of cases .

Vertebral anomalies (spina bifida, butterfly or hemivertebrae) are common. Laminar fusion associated with a neural arch defect is a good predictor of diastematomyelia and occurs the level of the defect, or at an adjacent level.

Antenatal ultrasound

The presence of an extra echogenic focus in the midline between the fetal spinal posterior elements has been described as a reliable sign .

Plain radiograph
CT

CT is able to better image many of the features seen on plain films and in addition may demonstrate the bony septum.

MRI

MRI is the modality of choice for assessing children with split cord malformations. As well as being able to elegantly demonstrate the cord and presence of hydromyelia (if present), it can also assess for the presence of the numerous associated anomalies (see above).

Differential diagnosis

Usually, there is little in the way of a differential diagnosis when the cord has been adequately imaged and features are typical (especially now that diplomyelia is considered part of the same spectrum by many authors ).

Siehe auch:
und weiter:
Assoziationen und Differentialdiagnosen zu Diastematomyelie:
Hämangiom
der Wirbelsäule
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Schmetterlingswirbel
 
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neuroenterische
Zyste
pediatricimaging.org • CC-by-nc-sa 4.0
Meningozele
 
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Cauda equina
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Sinus
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