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Neuroradiology Case of the Week

Case 432

August 2009

Derek Lasher, Ashwani Sharma, MD, and P-L Westesson MD, PhD, DDS

Clinical Presentation: Patient is a 47-year-old male who is status post-trauma.

Imaging Findings: CT scans revealed scoliosis in the cervical spine with concavity to the left side. C3, C4, and C5 vertebrae are fused. C4 is hemivertebra, with the left side absent.

Diagnosis: Cervical hemivertebra

Discussion: A hemivertebra is a vertebra which is underdeveloped, appearing wedge shaped. This results from a lack of ossification of half of the vertebral body. The majority of cases involve lateral deformity, though there are cases reported that involve hemivertebra in which deformity occurs in the dorsal/ventral plane [1].
     Hemivertebrae are classified into 3 categories, depending on their structure: semisegmented, fully segmented (non-incarcerated), and incarcerated vertebrae. Fully segmented, non-incarcerated hemivertebrae are the most common, and tend to cause the most problems, while segmented incarcerated hemivertebrae are the most rare, and cause the fewest major issues [2]. Fully segmented hemivertebrae are usually triangular in shape with the disc spaces above and below appearing to be relatively normal. The hemivertebra is wedged between two relatively normal vertebrae which often become slightly wedge-shaped during growth but the disc spaces are preserved. The lateral margin of the hemivertebra is equal or nearly equal in height to the adjacent vertebrae. Semi-segmented hemivertebrae are similar in shape to the fully segmented type but the body of the hemivertebra is synostosed with one of its neighboring vertebra, with no intervening disc space. The other disc space either above or below the hemivertebra is relatively normal. An incarcerated hemivertebra is usually more ovoid in shape and smaller than a fully segmented one. It is tucked into the spine and set in a niche scalloped out of the adjacent vertebrae. The vertebrae above and below are shaped in such a way that they tended to compensate for the hemivertebra and as a result the general alignment of the spine remains straight with minimal scoliosis. The disc spaces above and below the incarcerated hemivertebra are often narrow and sometimes poorly formed.
     Hemivertebrae have the potential to induce varying degrees of scoliosis, depending on the type of hemivertebra, the location of the hemivertebra, the number of hemivertebra and their interaction, and the age of the patient [2]. As the spine ages, it is not uncommon for some discs to harden and calcify. These sites are often called disc-osteophyte complexes, which have the potential to lead to other issues, such as myelopathy [3].
     Treatment for hemivertebra ranges from no treatment, to prophylactic treatments, to involved surgical treatments, such as spinal fusion and complete excision [2,4]. Disc-osteophyte complex treatment consists of rest, antiinflammatories, cervical traction, and physical therapy. Non-surgical treatment is all that is needed in the majority of patients, some cases, however, require surgical treatment for relief [3].

References:

1. Kumar R, Guinto FC Jr, Madewell JE, Swischuk LE, David R. The vertebral body: radiographic configurations in various congenital and acquired disorders. Radiographics. 1988 May;8(3):455-85. PMID: 3380991 [PubMed]
2. McMaster MJ, David CV. Hemivertebra as a cause of scoliosis. A study of 104 patients. J Bone Joint Surg Br. 1986 Aug;68(4):588-95. PMID: 3733836 [PubMed]
3. Patel A. The Spine and Aging. Kennedy-White Orthopaedic Center, Sarasota, Fl. 2004. http://www.kwoc.net/spinehandouts.htm. [PDF file]
4. Erol B, Kusumi K, Lou J, Dormans JP. Etiology of Congenital Scoliosis. University of Pennsylvania Orthopaedic Journal. 2002 Spring; 15: 37-42. [http://www.uphs.upenn.edu/ortho/oj/2002/html/oj15sp02p37.html]