The estimated incidence is at ~0.3 per 1000 live births 2.
It falls under the spectrum of segmentational 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.
Recognised associations are many and include:
- Aicardi syndrome
- cleidocranial dysostosis
- gastroschisis 3
- Gorlin syndrome
- fetal pyelectasis 3
- Jarcho-Levin syndrome
- OEIS complex
- VACTERL association
- mucopolysaccharidosis 9
This list supposed to be lot longer than this. If you know more, do add in with a relevant journal reference.
A hemivertebra can be classified according to many types which include:
- 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 segemental
- not separated from (i.e. connected to) either level above or below
- causes less of a concern
- joined by pedicles to levels above and below
- causes less of a concern
- dorsal hemivertebra: classically results in a kyphosis
- lateral hemivertebra: classically results in a scoliosis
- ventral hemivertebra (extremely rare): results in a lordosis
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 5.
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 dependant on the type of segmentation anomaly, from being a progressive to a non progressive deformity. The strongest negative impact is when a hemivertebra occurs at the lumbo-sacral level 7.
- cervical spine
- thoracic spine
- lumbar spine
- vertebral body
- neural arch
- transitional vertebrae
- ossification centres
- intervertebral disc
- anterior longitudinal ligament
- posterior longitudinal ligament
- posterior ligamentous complex
- cervical spine ligaments
- iliolumbar ligament
- musculature of the vertebral column
- spinal cord
- vascular supply
- 1. Varras M, Akrivis C. Prenatal diagnosis of fetal hemivertebra at 20 weeks' gestation with literature review. Int J Gen Med. 2010;3 : 197-201. Int J Gen Med (link) - Free text at pubmed - Pubmed citation
- 2. Goldstein I, Makhoul IR, Weissman A et-al. Hemivertebra: prenatal diagnosis, incidence and characteristics. Fetal. Diagn. Ther. 20 (2): 121-6. doi:10.1159/000082435 - Pubmed citation
- 3. Weisz B, Achiron R, Schindler A et-al. Prenatal sonographic diagnosis of hemivertebra. J Ultrasound Med. 2004;23 (6): 853-7. J Ultrasound Med (full text) - Pubmed citation
- 4. Chen M, Chan B, Lam TP et-al. Sonographic features of hemivertebra at 13 weeks' gestation. J. Obstet. Gynaecol. Res. 2007;33 (1): 74-7. doi:10.1111/j.1447-0756.2007.00483.x - Pubmed citation
- 5. Ryu JK, Cho JY, Choi JS. Prenatal sonographic diagnosis of focal musculoskeletal anomalies. Korean J Radiol. 4 (4): 243-51. Korean J Radiol (link) - Free text at pubmed - Pubmed citation
- 6. Vaccaro AR, Albert TJ. MasterCases, spine surgery. Thieme Medical Pub. (2001) ISBN:0865779244. Read it at Google Books - Find it at Amazon
- 7. Heary RF, Albert TJ. Spinal deformities, the essentials. Thieme. (2007) ISBN:1588903419. Read it at Google Books - Find it at Amazon
- 8. Dewald RL. Spinal deformities, the comprehensive text. Thieme Medical Pub. (2003) ISBN:1588900894. Read it at Google Books - Find it at Amazon
- 9. Lachman RS, Burton BK, Clarke LA et-al. Mucopolysaccharidosis IVA (Morquio A syndrome) and VI (Maroteaux-Lamy syndrome): under-recognized and challenging to diagnose. Skeletal Radiol. 2014;43 (3): 359-69. doi:10.1007/s00256-013-1797-y - Free text at pubmed - Pubmed citation