Lumbar spine variationsand anomalies

Lumbar spine variations and anomaliesThe purpose of this presentation is to allow students to review the essentials of Normal Radiographic Anatomy. The information within is designed to be a supplement to the lecture and lab material. In no way should completely replace those tools. The material presented in the following pages augments the material within the traditional class and lab setting. This presentation should not be used exclusively in the pursuit of testable knowledge for the class.

Created by: Jean-Nicolas Poirier, DC, DACBR

Lumbar spine variations and anomalies This presentation was created using information from the excellent references mentioned above

A. 14 months old girl. The spinal canal appears disproportionately wide in relation to the vertebral bodies. The laminae are thin and the interlaminar spaces are wide. D. 10 year old boy. The spinal canal remains wide. The neural arches fused between 5 and 6 years of age. The superior vertebral endplates have a serrated appearance. E. 13 year old boy. The secondary ring apophyses have begun to ossify and are visible (arrows).

A. 30 months old girl. The vertebral body contours are rounded and the vertebral canal appears disproportionately wide. C. 11 year old girl. The secondary ring apophyses are seen adjacent to the normally notched anterior vertebral body margins. These ossification centers typically appear at puberty and fuse to the vertebral body between 17 and 25 years of age. E. 15 year old boy. Prominent notch-like defects of the vertebral bodies of T12, L1 and L2, normal in the juvenile spine, representing the space occupied by the unossified secondary ossification centers. Ossified centers are seen at T10 and T11. G. 22 year old man. The secondary ossification centers have fused. The vertebral bodies are more rectangular and the vertebral endplates have less exaggerated curvilinear appearance.

Nuclear impressions (notochordal impression). 26. Year old man demonstrates prominent, broad-based, curvilinear depressions of the vertebral endplates. These are usually more prominent at the inferior endplates and represent a normal variation of vertebral contour and should not be confused with fractures, Schmorls nodes or pathologic destruction.

Cupids bow contour. Normal paramedian curvilinear impressions of the inferior endplates of the L4 and L5 vertebral bodies.

Developmental synostosis (block vertebrae). Failure of segmentation of two contiguous vertebral segments. The rudimentary intervertebral disc is calcified. The central portion of the vertebrae is hypoplastic (wasp-waist appearance). The degenerative intervertebral disc space narrowing and osteophyte formation, seen at adjacent levels, are frequent complications of block vertebrae.

Lumbar ribs. Small hypoplastic tranverse processes of L1 articulate with rudimentary anomalous ribs. This anomaly is of no clinical significance.

Spina bifida occulta. A. 26 year old man with nonunion of anomalous L5 laminae, seen as a radiolucent defect (white arrow), results in incomplete development of the spinous process. Another small midline defect is seen at S1. B. In another patient, midline radiolucent defects represent incomplete formation of the spinous processes of L4 and L5 and the first sacral tubercle.

Clasp-knife (knife-clasp) deformity. Manual laborer with back pain exacerbated by extension. Inferior sloping and elongation of the L5 spinous process in conjuction with spina bifida occulta of S1. The CT scan demonstrates the L5 spinous process penetrating the S1 SBO and contacting the thecal sac, a finding consistent with the patient symptoms.

Lateral hemivertebra. Incomplete, triangular vertebral body and corresponding pedicle is incorporated within the L4-L5 intervertebral disc space. Compensatory remodeling of the adjacent vertebral bodies and asymmetric degenerative disc disease also are seen at this level. Hemivertebrae frequently result in congenital scoliosis.

Facet tropism. Asymmetry of the lumbosacral apophyseal joint orientation. The left apophyseal joint is oriented in the sagittal plane and the right apophyseal joint is oriented prominently in the coronal place. CT or MRI are usually necessary to determine the precise facet joint orientation but such an examination is usually not warranted for this purpose. There is stapulation of the right transverse process of L5 articulating with the sacral ala.

Ununited secondary ossification center of the right inferior articular process. This anomaly is seen most frequently at L3 and L4, has been referred to as Oppenheimers ossicle and should be differentiated from a fracture.

Agenesis of the lumbosacral articular process. Observe the absence of the right inferior articular process of L5. In this rare, stable and often asymptomatic anomaly, a nonossified cartilaginous or fibrous analogue is present.

Lumbosacral transitional segments. C. Large left spatulated transverse process of L5 articulating with the left sacral ala and ilium. The right transverse process is normal. E. Elongated L4 transverse processes and large, spatulated transverse processes of L5 articulating bilaterally with the ilium and sacral alae. B. Both transverse processes are enlarged and spatulated and fused the sacral alae. This appearance is termed sacralization.

Diastematomyelia. CT scan. A sagittally oriented vertical osseous bar divides the L3 thecal sac in this 22 year old woman. Conventional radiographs may demonstrate the vertically oriented osseous bar with widened interpedicular distance. The septum can also be of cartilaginous or fibrous nature and therefore not seen on plain films. MRI and CT are best to evaluate the neurological changes associated with this anomaly.

Dysplastic (type I) and degenerative (type III) spondylolisthesis of L4 on L5. There is a wedge-shaped appearance of the anterosuperior margin of the L5 vertebral body with short pedicles at this level. The dysplastic appearance of L5, combined with degenerative changes at the facet joints of L4-L5, has led to an anterior translation of L4 on L5.

Spondylolysis at L5. A. 10 years old girl with back pain following gymnastic exercises. A radiolucent pars interarticularis defect (spondylolysis) is seen with minimal spondylolisthesis. B,C. Pars interarticularis defects in another patient are visualized at L4 on the frontal and oblique projections. D. CT san demonstrating an example of unilateral spondylolysis.

A. Grade 1 spondylolytic spondylolisthesis of L5 on S1. B. Inverted Napoleon hat sign or bowline of Brailsford sign characteristic of grades 3 to 5 spondylolisthesis of L5 on S1 where the last lumbar segment is slipped forward and angulated downwards leading to transverse visualization of L5 on the frontal view.

Degenrative spondylolisthesis of L3 on L4 and L4 on L5. 74 year old woman with chronic low back pain reveals severe apophyseal joint osteoarthrosis and anterior displacement of both L3 and L4.

Pathological spondylolysis. 26 year old male with osteopetrosis (sclerotic bone dysplasia) demonstrates multiple pars interarticularis fractures presumably secondary to the brittle nature of his bones. Note the charasteristic sandwich vertebra appearance of the vertebral bodies in osteopetrosis.

Wilkinson syndrome. A. Right unilateral hypertrophic and sclerotic pedicle. A subtle pars interarticularis defect is noted on the left (arrow). B. The oblique projection better displays the pars fracture. C. CT scan demonstrates the right hypertrophic and sclerotic pedile and left pars interarticularis fracture. Wilkinson syndrome refers to an hypertrophic and sclerotic pedicle secondary to long lasting biomechanical stresses in a patient with contralateral pars interarticularis defect.

Instability evaluation in spondylolisthesis. A. Radiograph obtained with a compressive device shows 7 mm of anterior translation of L5 on S1. B. Film obtained with traction reveals a reduction of the anterolisthesis to 2mm. In addition, the disc space is widened and intradiscal gas (vacuum phenomenon) is evident. Sagittal translation on functional radiographs in excess of 4 mm indicates instability and implies a higher probability of progression (slippage) of the spondylolisthesis.

Intradiscal vacuum phenomenon. E. Small radiolucent lines are seen at the anterior aspect of the intervertebral discs adjacent to the vertebral endplates. These radiolucencies are thought to represent annular tears associated with spondylosis deformans. F. The vacuum phenomenon is seen predominantly in the nucleus pulposus and is characteristic of intervertebral osteochondrosis. The presence of gas in fibrocartilaginous joints is usually a sign of degeneration. On the opposite side, the presence of gas in a synovial joint is usually a normal finding and should be differentiated from an iatrogenic or traumatic perforation or gas producing septic arthritis.

Schmorls (cartilaginous) node. Schmorls nodes are evident in two adjacent vertebral bodies in this patient with Scheuermanns disease. Observe the focal radiolucent depressions with adjacent sclerotic margins, representing intrabody disc herniations. Schmorls nodes are a common radiographic feature secondary to either a congenital weakening of the cartilaginous endplates or trauma- induced focal endplate fracture. These acquired post-traumatic endplates fractures are acutely painful. The old Schmorls nodes are usually asymptomatic.

Limbus vertebra. Triangular sclerotic bone fragment is seen adjacent to the anterosuperior margin of the vertebral body (arrow). A radiolucent cleft separating the fragment from the vertebral body is noted. The limbus bone represents the residual calcified apophyseal ring that was separated from the vertebral body during adolescence. Multiple Schmorls nodes are also observed (open arrows).