2. Superior articular process (right)
3. Pars interarticularis / isthmus (right)
4. Lamina (right)
5. Inferior articular process (right)
6. Transverse process (right)
7. Spinous process
8. Intervertebral disc
9. Interlaminar space
10. Transverse process (left)
11. Inferior articular process (left)
12. Superior articular process (left)
13. Lamina (left)
14. Vertebral body
viewing the lumbar spine in a anterior oblique view the result is an image
which resembles a "Scotty Dog". A fracture of
the par interarticularis (isthmus)
results on the X-Ray as a dark "collar" on the neck of the dog (#3
Research Abstracts: from Med-line the National Library of Health
TITLE: The radiological investigation of lumbar spondylolysis.
AUTHORS: Harvey CJ; Richenberg JL; Saifuddin A; Wolman RL
AUTHOR AFFILIATION: Department of Radiology, The Royal National Orthopaedic Hospital Trust, Stanmore, Middlesex, UK.
SOURCE: Clin Radiol 1998 Oct;53(10):723-8
CITATION IDS: PMID: 9817088 UI: 99031978
ABSTRACT: Lumbar spondylolysis represents a stress fracture of the pars interarticularis and occurs most commonly at the L5 level. Pars defects can be imaged with plain radiography, bone scintigraphy, computed tomography (CT) and magnetic resonance imaging (MRI). Plain radiographic projections of particular value include the coned lateral view of the lumbosacral junction, which displays the majority of defects, and the anteroposterior view with 30 degrees cranial angulation. The value of oblique radiography is unproven. Planar bone scintigraphy (PBS) is more sensitive than radiography and single photon emission computed tomography (SPECT) more sensitive and specific than PBS. Both these techniques, however, are less specific than radiography and CT. CT, when performed with a reverse gantry angle and thin sections, is the investigation of choice for identifying radiographically occult lyses. Conventional lumbar spine MRI techniques are valuable for demonstrating normality of the pars, but may be associated with a high false positive rate for the diagnosis of pars defects.
TITLE:Traumatic L5-S1 spondylolisthesis.
AUTHORS: Hodges SD; Shuster J; Asher MA; McClarty SJ
AFFILIATION:Chattanooga Orthopaedic Group, Foundation for Research, Tenn, USA.
SOURCE:South Med J 1999 Mar;92(3):316-20
CITATION IDS: PMID: 10094275 UI: 99192088
ABSTRACT: We report a case of traumatic spondylolisthesis in a 31-year-old man struck by a steel I-beam. Although most reported traumatic spondylolisthesis cases are from low-energy trauma, this was a high- energy trauma case. The initial examination revealed no signs of cauda equina syndrome, and the patient's spinal injury was primarily capsuloligamentous. We present this rare case, with a review of pertinent literature and treatment mechanisms for traumatic spondylolisthesis.
TITLE: Facet joint remodeling in degenerative spondylolisthesis: an
investigation of joint orientation and tropism.
AUTHORS: Berlemann U; Jeszenszky DJ; Buhler DW; Harms J AUTHOR
AFFILIATION: Department of Orthopaedic Surgery, Inselspital, University of Bern, Switzerland.
SOURCE: Eur Spine J 1998;7(5):376-80 CITATION IDS: PMID: 9840470 UI: 99054205
ABSTRACT: This study analyzed transverse facet joint angulations at the three lower lumbar levels in 132 patients assigned to one of four groups. Group A comprised 23 patients with degenerative spondylolisthesis (DS) at the level L4-5, group B comprised 40 patients above the age of 50 years, group C comprised 38 patients aged between 35 and 50 years, and group D comprised 31 patients under the age of 35 years. Groups B, C, and D had no evidence of DS. Measurements were taken from hard copies of axial MR or CT images. The transverse plane of facet joints was more sagittally oriented in group A than in any other group. This difference was highly significant at the L4-5 level. The incidence of more sagittally oriented L4-5 facet joints was also significantly higher only in group A. The incidence of facet joint tropism, however, was not different in group A. These results support the view that the pronounced sagittal alignment of facet joints in patients with DS represents a secondary remodeling rather than a pre-existing morphology. Facet joint asymmetry does not seem to play a major role in the development of DS.
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