Diastematomyelia

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Diastematomyelia
Diastematomelia in MRI of lumbar spine.
SpecialtyMedical genetics Edit this on Wikidata

Diastematomyelia (occasionally diastomyelia) is a

fibrous septum in the central portion of the spinal canal which then produces a complete or incomplete sagittal division of the spinal cord into two hemicords. When the split does not reunite distally to the spur, the condition is referred to as diplomyelia, which is true duplication of the spinal cord.[1][additional citation(s) needed
]

Signs and symptoms

The signs and symptoms of diastematomyelia may appear at any time of life, although the

Cutaneous lesions (or stigmata), such as a hairy patch, dimple, Hemangioma, subcutaneous mass, Lipoma or Teratoma over the affected area of the spine is found in more than half of cases. Neurological symptoms are nonspecific, indistinguishable from other causes of cord tethering. The symptoms are caused by tissue attachments that limit the movement of the spinal cord within the spinal column. These attachments cause an abnormal stretching of the spinal cord.[citation needed
]

The course of the disorder is progressive. In children, symptoms may include the "

deformities; weakness in the legs; low back pain; scoliosis; and incontinence
. In adulthood, the signs and symptoms often include progressive sensory and motor problems and loss of bowel and bladder control. This delayed presentation of symptoms is related to the degree of strain placed on the spinal cord over time. Tethered spinal cord syndrome appears to be the result of improper growth of the neural tube during fetal development, and is closely linked to spina bifida.

Tethering may also develop after spinal cord injury and scar tissue can block the flow of fluids around the spinal cord. Fluid pressure may cause

cysts to form in the spinal cord, a condition called syringomyelia. This can lead to additional loss of movement, feeling or the onset of pain or autonomic
symptoms.

Cervical diastematomyelia can become symptomatic as a result of acute trauma, and can cause major neurological deficits, like hemiparesis, to result from otherwise mild trauma.[2]

The following definitions may help to understand some of the related entities:[citation needed]

Pathophysiology

Diastematomyelia is a "

Arnold–Chiari malformations have been described in medical literature, but they are exceptionally rare.[citation needed
]

Diastematomyelia usually occurs between 9th

ventral horn (giving rise to a ventral nerve root.) One study showed the bony spur typically situated at the most inferior aspect of the dural cleft. They advised that if the imaging appears to show otherwise, a second spur (present in about 5% of patients with diastematomyelia) is likely to be present.The conus medullaris is situated below the L2 level in more than 75% of these diastematomyelia patients. Thickening of the filum terminale
is seen in over half of the cases. While the level of the cleft is variable, it is most commonly found in the lumbar region. The two hemicords usually reunite caudally to the cleft. Occasionally, however, the cleft will extend unusually low and the cord will end with two separate coni medullarae and two fila terminale ("Diplomyelia").

Diagnosis

Adult presentation in diastematomyelia is unusual. With modern imaging techniques, various types of spinal

CT
scan is the most effective diagnostic tool in demonstrating the detailed bone, intradural and extradural pathological anatomy of the affected and adjacent spinal canal levels and of the bony spur.

myelodysplasia, dysraphia
of the spinal cord.

Treatment

Surgery
Surgical intervention is warranted in patients who present with new onset neurological signs and symptoms or have a history of progressive neurological manifestations that can be related to this abnormality. The surgical procedure required for the effective treatment of diastematomyelia includes decompression (surgery) of neural elements and removal of bony spur. This may be accomplished with or without resection and repair of the duplicated dural sacs. Resection and repair of the duplicated dural sacs is preferred since the dural abnormality may partly contribute to the "tethering" process responsible for the symptoms of this condition.

Post-myelographic CT scanning provides individualized detailed maps that enable surgical treatment of cervical diastematomyelia, first performed in 1983.[2][3]

Observation
Asymptomatic patients do not require surgical treatment. These patients should have regular neurological examinations since it is known that the condition can deteriorate. If any progression is identified, then a resection should be performed.

References

  1. ISBN 978-0-12-385158-1
    . Retrieved 28 February 2023.
  2. ^ a b Kuchner, E.F., Anand, A.K. & Kaufman, B.M., "Cervical Diastematomyelia" Neurosurgery, 16(4): 538-542, 1985
  3. ^ Anand, A.K., Baim, R.S. & Kuchner, E.F., "Cervical Diastematomyelia" Computerized Radiology. 9(1):45-49, 1985

External links

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