Spondylolisthesis and posterior instability.

We present the case of a patient with a spondylolisthesis of L5 on S1 due to spondylolysis at the level L5/S1. The vertebral slip was fixed and no anterior instability was found. Using functional magnetic resonance imaging (MRI) in an upright MRI scanner, posterior instability at the level of the spondylolytic defect of L5 was demonstrated. A structure, probably the hypertrophic ligament flava, arising from the spondylolytic defect was displaced toward the L5 nerve root, and a bilateral contact of the displaced structure with the L5 nerve root was shown in extension of the spine. To our knowledge, this is the first case described of posterior instability in patients with spondylolisthesis. The clinical implications of posterior instability are unknown; however, it is thought that this disorder is common and that it can only be diagnosed using upright MRI.

Spondylolysis and isthmic spondylolisthesis: impact of vertebral hypoplasia on the use of the Meyerding classification.

BACKGROUND: Spondylolysis and isthmic spondylolisthesis are common multifactorial disorders. The extent of slipping of the spondylolytic vertebra is considered a major predicator for prognosis and further follow-up. Vertebral hypoplasia is a common finding associated with spondylolysis. The purpose of this study is to evaluate the incidence of hypoplastic vertebral bodies in patients with spondylolysis and in the general population and to analyse the impact of the findings on the measurement and grading of spondylolisthesis. METHODS: 140 patients with 141 levels of spondylolysis identified by MRI were included in this study. The slippage of the spondylolytic vertebral body and the size in the midline sagittal image were measured and correlated. In addition, a randomised control group was evaluated to test the hypothesis that shortened, hypoplastic vertebral bodies can also be found in the general population. RESULTS: Shortened, hypoplastic vertebrae were found in 50 patients with spondylolysis and none was found in the control group. These shortened vertebrae mimicked spondylolisthesis and in 19 patients the slippage equalled the shortening, thus mimicking spondylolisthesis, although only spondylolysis was present. CONCLUSION: Sagittal shortening of the spondylolytic vertebra is common and may mimic spondylolisthesis. In order to define and measure spondylolisthesis the shortening of the spondylolytic vertebra has to be taken into account.

Position dependent changes of the cerebral venous drainage--implications for the imaging of the cervical spine.

PURPOSE: This study demonstrates the physiological changes of the cerebral venous outflow routes in healthy humans in the recumbent and the sitting position employing positional MRI. METHODS: In five volunteers, the internal jugular veins and the cervical vertebral plexus were analyzed in the supine and sitting position using an open MR system. Axial T2-weighted scans and axial T1-weighted flow sensitive gradient echo sequences were acquired. The findings were compared to previously published anatomic descriptions from cadaver preparations. RESULTS: In the supine position, the internal jugular vein is the main route for the cerebral venous outflow. The mean area was 100 mm (2) (±29 mm (2)) for both sides together. In the sitting position, the jugular vein collapses (mean area: 11 mm (2)±2 mm (2)) and the vertebral venous plexus becomes more prominent. CONCLUSION: The position dependent changes in cerebral venous outflow can be imaged using positional MRI. The vertebral venous plexuses may mimic pathologies and physicians reading positional MRI images of the cervical spine should be aware of the physiological changes occurring in the erect position.

Spondylolysis and spondylolisthesis: prevalence of different forms of instability and clinical implications.

STUDY DESIGN: Imaging study with an evaluation of incidences and clinical correlation. OBJECTIVE: To evaluate the incidence of 3 different types of instabilities in patients with spondylolysis or isthmic spondylolisthesis. Clinical findings are correlated with imaging findings, and the imaging findings are analyzed with regard to their clinical implications. SUMMARY OF BACKGROUND DATA: Spondylolysis and isthmic spondylolisthesis are common disorders. An unstable slip is the most well-known form of instability, but other forms also exist. However, the incidence of these instabilities and their clinical implications are yet unclear. METHODS: A total of 140 patients with 141 levels of spondylolysis identified by MRI (magnetic resonance imaging) were included in this study. Using positional MRI, the instability of the slip, an increased angular movement, and movement in the spondylolytic cleft were assessed. On the basis of clinical findings, the patients were classified as presenting with either radicular or nonradicular symptoms. The incidence of the instabilities was recorded and correlated with the incidence of radicular symptoms. RESULTS: Fifteen patients had an unstable slip (anterior instability); 35, an increased angular movement (angular instability); and 34 patients, a movement in the spondylolytic cleft (posterior instability). All forms of instability could be found together. No instability at all was found in 76 patients. Radicular symptoms were found significantly more often in patients with one or more of the described instabilities compared with patients without instability. CONCLUSION: All 3 described forms of instability are common in spondylolysis or isthmic spondylolisthesis and associated with radicular pain. This finding stresses the value of positional MRI in the evaluation of patients with spondylolysis and isthmic spondylolisthesis, especially if radicular symptoms are present.

[Pathomechanisms of spinal canal stenosis - upright MRI image gallery]. / Pathomechanismen der spinalen Enge - Upright-MRT-Bildergalerie.

AIM: Lumbar spinal canal stenosis is a common disease of the elderly patient, with a high prevalence and clinical importance. MRI is the established method of choice for the imaging of spinal canal stenosis. However, there is often a discrepancy between the clinical symptoms and the spinal canal stenosis as shown using MRI in a supine position. In such cases preoperative functional imaging is often warranted. METHODS: In an image gallery three cases of a functional spinal canal stenosis of the lumbar spine are shown. In all three patients a dynamic, positional MRI (upright MRI) was performed. RESULTS: The pathomechanisms of the spinal canal stenosis could be shown in all three cases. CONCLUSION: Using upright MRI a functional spinal canal stenosis can be shown. The pathomechanisms of the spinal canal stenosis are discussed. The possibilities and limitations of this new imaging modality are presented and analysed.

[The importance of 201-thallium myocardial scintigraphy in the hypertensive patient]. / Bedeutung der 201Thallium-Myokardszintigraphie beim Hypertoniker.

Thallium-201 exercise myocardial scintigraphy was performed in 57 patients (37 males, 20 females; mean age 55.4 [43-78] years) with angina and systemic hypertension after exclusion by coronary angiography of any coronary macroangiopathy. The exercise ECG of 32 patients could not be used in the diagnosis of ischaemia because of the presence of left ventricular hypertrophy with abnormal repolarization or left bundle branch block. Abnormal haemodynamics were demonstrated at cardiac catheterization in 23 patients (Swan-Ganz). Only 10 of the studied hypertensives with normal coronary angiograms had a myocardial scintigram within normal limits, while 12 had extensive ischaemic zones in the left ventricle. All patients with left bundle branch block had evidence of exercise-dependent apical "ischaemia". Thallium-201 myocardial scintigraphy should not be used as a screening method in hypertensives with angina, because the high proportion of "false-positive" findings, in the sense of a macroangiopathy, will nevertheless require early invasive diagnosis.