Malformed vertebrae: a clinical and imaging review

Abstract

A variety of structural developmental anomalies affect the vertebral column. Malformed vertebrae can arise secondary to errors of vertebral formation, fusion and/or segmentation and developmental variation. Malformations can be simple with little or no clinical consequence, or complex with serious structural and neurologic implications. These anomalies can occasionally mimic acute trauma (bipartite atlas versus Jefferson fracture, butterfly vertebra versus burst fracture), or predispose the affected individual to myelopathy. Accurate imaging interpretation of vertebral malformations requires knowledge of ageappropriate normal, variant and abnormal vertebral morphology and the clinical implications of each entity. This knowledge will improve diagnostic confidence in acute situations and confounding clinical scenarios.This review article seeks to familiarize the reader with the embryology, normal and variant anatomy of the vertebral column and the imaging appearance and clinical impact of the spectrum of vertebral malformations arising as a consequence of disordered embryological development.Teaching points • Some vertebral malformations predispose the affected individual to trauma or myelopathy. • On imaging, malformed vertebrae can be indistinguishable from acute trauma. • Abnormalities in spinal cord development may be associated and must be searched for. • Accurate interpretation requires knowledge of normal, variant and abnormal vertebral morphology.Electronic supplementary materialThe online version of this article (10.1007/s13244-018-0598-1) contains supplementary material, which is available to authorized users.

Anatomical Variations That Can Lead to Spine Surgery at The Wrong Level: Part II Thoracic Spine

“…It is a congenital variant that develops when one of two chondrification centers fails to form [12]. It is most commonly found in the midthoracic spine, particularly at the T8 level [13]. There are four distinct types: Incarcerated, nonincarcerated, segmented, and unsegmented ( Figure 3) [13].…”

“…It is most commonly found in the midthoracic spine, particularly at the T8 level [13]. There are four distinct types: Incarcerated, nonincarcerated, segmented, and unsegmented ( Figure 3) [13]. Incarcerated hemivertebrae are those in which the vertebral bodies above and below the abnormal segment accommodate the hemivertebrae, while nonincarcerated refers to the failure of accommodation, which results usually in spinal curvature.…”

“…Incarcerated hemivertebrae are those in which the vertebral bodies above and below the abnormal segment accommodate the hemivertebrae, while nonincarcerated refers to the failure of accommodation, which results usually in spinal curvature. Segmented, or free, hemivertebrae have a normal disk above and below the defective body and are more likely to lead to progressive curvature, while unsegmented hemivertebrae are fused with the vertebral body above and below [13]. Hemivertebrae can lead to angulation of the thoracic spine, resulting in kyphosis, lordosis, or scoliosis.…”

Anatomical Variations That Can Lead to Spine Surgery at the Wrong Level: Part III Lumbosacral Spine

“…It is believed to be due to the failure of chondrification centers to develop during fetal life (Figure 4) [23]. Four types of hemivertebra are described: incarcerated, nonincarcerated, segmented, and unsegmented [24]. Incarcerated hemivertebrae are typically imprisoned within lateral margins of two adjacent vertebrae above and below.…”

“…Conversely, in nonincarcerated type, the contiguous normal vertebrae are completely separated from each other, housing the wedged hemivertebra in between. Segmented hemivertebra is classically situated between two intervertebral discs, and is associated with more deterioration and subsequent spinal curvature than unsegmented hemivertebra, which has fibrous tissue above and beneath it (i.e., fused with adjacent vertebra) [24]. A study of lumbar spine radiographs found that approximately 0.27% of asymptomatic individuals had hemivertebra [23].…”