Scheuermann's disease: the lumbar variant.

Abstract

Kyphosis dorsalis juvenilis was described by Holger Werfel Scheuermann in 1921 when he noted the development of painful fixed kyphosis in 105 children. Radiographs showed compression of the anterior vertebral borders, with a wedge deformity and irregular epiphyseal centers. Scheuermann thought it similar to the femoral head abnormality described by Calve and Perthes and named it osteochondritis deformans juvenilis dorsi. 1 This entity has gone by many names, but it is most frequently called Scheuermann's disease. Scheuermann's disease is the second most common cause of back pain in children after spondylolysis with spondylolisthesis. 2 It usually presents in adolescence with the insidious onset of thoracic kyphosis and back pain that is worse in the afternoons and relieved with rest. Symptoms are typically attributed to poor posture, and medical evaluation is often delayed. This abnormality has a prevalence in the general population of 4– 8%, involving girls and boys equally. 2 Physical exam is remarkable for a fixed kyphotic deformity, most often in the thoracic region. Adam's test can be used to help differentiate from postural irregularities. When examined from the side, flexible postural abnormalities of the spine will generally smooth out when the patient is asked to bend forward. In Scheuermann's, the kyphosis will remain unchanged. Hyperlordosis of the cervical and lumbar spine is often found, along with forward head position. Up to a third of these individuals will have mild scoliosis. 2 Sorenson established radiographic criteria for the diagnosis in 1964. 3 He described >5 degrees of anterior wedging in at least three adjacent vertebral bodies along with one associated sign in the lumbar region. The associated findings can include Schmorl's nodes, irregularity and flattening of vertebral endplates, narrowing of intervertebral disc spaces, and anteroposterior elongation of apical vertebral bodies. 3 Schmorl's nodes occur when material for the nucleus pulposus extrudes through the endplate and into the vertebral body. These tend to occur centrally in classic Scheuermann's and anteriorly in the atypical lumbar form of the disorder. Radiographically, Schmorl's nodes appear as incongruous depressions of the endplate. 4 In Scheuermann's disease, multilevel endplate extrusions of disk material may be caused by delayed closure of endplate ossification centers. With the lumbar variant, only one or two vertebrae are involved, and they usually lie between T10 and L4. 3 In the T1-weighted magnetic resonance image presented in Figure 1, the thoracolumbar spine of a 27-yr-old man with a 13-yr history of nonradiating mid and low back pain is pictured. Multiple Schmorl's nodes appear as irregularities at the endplates, primarily in the upper lumbar region. There is also disk herniation at L1-2, with compression of the thecal sac, a known complication. The sharp angulation described in classic thoracic Scheuermann's is not seen here.Figure 1:: Magnetic resonance image of the thoracolumbar spine. Schmorl's nodes (each marked by a white asterisk) are seen as multiple areas where disk material extrudes through the endplate in the lumbar region. Disk herniation at L1-2 (marked by black arrow) with compression of the thecal sac is also prominent.For most patients, Scheuermann's disease runs a fairly benign course, with resolution of symptoms at skeletal maturity. However, as described above, these individuals are more likely to have disk herniations in adulthood that may be neurologically devastating. At the apex of the kyphosis, adults often have pain along with varying degrees of degenerative spondylolysis and spondylolisthesis. The lumbar variant is more likely to be progressive in adulthood and more often symptomatic. 2