Pilot Study of the Dynamic Effects of Simulated Axial Loading MagneticResonance Imaging in Lumbar Disc Herniation

摘要

Study Design: A pilot study of lumbar disc herniation patients examined with magnetic resonance imaging inboth psoas-relaxed position and axial compression in extension of the lumbar spine is described. Objective: To discuss theclinical value of axially loaded magnetic resonance imaging in patients with lumbar disc herniation and to evaluate theeffect on the dural cross-sectional area. Summary of Background Data: Magnetic resonance imaging tests are performedin a supine relaxed position. It is well documented that a narrowing of the spinal canal is provoked by axial loading,especially when it is combined with spinal extension. Physiological or pathological changes due to loading effects mightthus remain undetected by conventional imaging tests. This unloading effect could lead surgeons to a diagnosis that doesnot take into account these dynamic aspects. The present pilot study seeks to evaluate the effect of axial loadingcompression on the dural cross-sectional area in patients with lumbar disc herniation. The purpose of this study is to helpsurgeons in making treatment decisions or surgery indications. Methods: 15 patients underwent magnetic resonanceimaging examinations in both psoas-relaxed position and axial compression in extension using a compression device(DynaWell?). An axial load corresponding to 50% of the body weight was applied. Changes in the dural cross-sectionalarea were registered. Results: A significant decrease in dural cross-sectional area was found in only 2 patients (13.3%). In13 patients, no significant changes in dural cross-sectional area were found. Concerning the overall results, no significantdifferences were observed between both MRI. Conclusions: Using magnetic resonance imaging, no statistical significantdecrease in dural cross-sectional area after axial loading was found. These findings do not support the recommendation ofmagnetic resonance imaging with axial compression in patients with sciatica secondary to lumbar disc herniation.