Halbwirbel

Mehrere
angeborene Blockwirbel im Übergang von der Brust- zur Lendenwirbelsäule und Halbwirbel bei hemimetamerer Segmentverschiebung an der oberen Brustwirbelsäule.
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Verschmelzungsanomalie
mit Halbwirbel und Blockwirbel LWK 2 und 3.
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Halbwirbel
HWK 5 im Röntgenbild.
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Hemimetamere
Segmentverschiebung HWK 6 / 7 oder Halbwirbel. Leider keine Aufnahme weiter kaudal vorhanden, so dass nicht gesagt werden kann, ob ein gegenläufiger Halbwirbel links weiter kaudal existiert oder es "nur" ein singulärer Halbwirbel ist.
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School ager
with congenital anomaly of the urinary tract. AP image from a selective angiogram injection of the left renal artery shows fusion of the medial aspect of the left kidney, which has crossed the midline, to the medial aspect of the right kidney, causing the right kidney to be displaced laterally. A right hemivertebra is also present just above the T10 vertebral body.The diagnosis was cross fused renal ectopia in a patient with a hemivertebra.
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School ager
with a posterior mediastinal mass. CXR AP shows a round soft tissue density in the superior and medial aspect of the right hemithorax which was found on cross sectional imaging to be in the posterior mediastinum, along with multiple hemivertebra segmentation anomalies of the lower cervical and upper thoracic spine causing a curvature of the upper thoracic spine convex to the right.The diagnosis was congenital scoliosis secondary to hemivertebra in a patient with a neurenteric cyst.
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Hemivertebra is a type of vertebral anomaly and results from a lack of formation of one half of a vertebral body. It is a common cause of congenital scoliosis.

Epidemiology

The estimated incidence is at ~0.3 per 1000 live births .

Pathology

It falls under the spectrum of segmentation anomalies and can involve one or multiple levels.

A hemivertebra acts as a wedge within the vertebral column, resulting in curvature away from the side on which it is present.

Associations

Recognized associations are many and include:

Classification

A hemivertebra can be classified according to many types which include:

Attachment
  • fully segmental (free)
    • not attached to either vertebra above or below
    • most concerning
  • semi segmental: half segment is fused with vertebra above or below with no intervening intervertebral disc
  • non-segmental
    • not separated from (i.e. connected to) either level above or below
    • causes less of a concern
  • incarcerated
    • joined by pedicles to levels above and below
    • causes less of a concern
Orientation 

Radiographic features

Antenatal ultrasound

A hemivertebra may be seen as an asymmetrical vertebral body on sagittal or coronal scanning, while on axial scanning, a focal defect may be seen on either side of the vertebral column .

Plain radiograph / CT

Usually directly outlines the bony anomaly and is often seen as a wedge-shaped vertebral body.

Treatment and prognosis

The prognosis can be variable dependent on the type of segmentation anomaly, from being progressive to a non-progressive deformity. The strongest negative impact is when a hemivertebra occurs at the lumbosacral level .

Differential diagnosis

Consider

Siehe auch:
und weiter:
Assoziationen und Differentialdiagnosen zu Halbwirbel:
Blockwirbel
 
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hemimetamere
Segmentverschiebung
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Kongenitale
Skoliose
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