Herniated Lumbar Disks: Real-time MR Imaging Evaluation during Continuous Traction.

Abstract

To assess the morphologic changes in herniated lumbar intervertebral disks and surrounding structures during lumbar traction by using real-time magnetic resonance (MR) imaging. This prospective study was approved by the institutional review board, and written informed consent was obtained from all participants. Forty-eight consecutive patients with lumbar disk herniation (13 men and 35 women) were treated with continuous lumbar traction by using a nonmagnetic traction device. Real-time MR imaging of the lumbar spine was performed before the initiation of traction and at 10-minute intervals during 30 minutes of 30 kg of continuous traction. Sagittal and axial MR images were analyzed to determine qualitative changes during lumbar traction. Quantitative changes caused by traction on the lumbar spine were determined by measurement of lumbar vertebral column elongation and the disk reduction ratio. Continuous traction on herniated lumbar disks and surrounding structures resulted in change in disk shape, disk reduction with opening in the intervertebral disk, reduction of herniated disk volume, separation of the disk and adjoining nerve root, and widening of the facet joint. Both the mean lumbar vertebral column length (elongation of 1.45% after 30 minutes, P < .001) and the mean disk reduction ratio (8.57%, 15.24%, and 17.94% after 10, 20, and 30 minutes of traction, respectively) increased with time of traction. The results of this study demonstrated that the real-time effects of continuous traction on herniated lumbar intervertebral disks and their surrounding structures can be visualized by using MR imaging.